The parable of those who take to them other than God for guardians (to entrust their affairs to) is like a spider: it has made for itself a house, and surely the frailest of houses is the spider’s house. If only they knew this! (Qur’an, 29:41)

A prehistoric Greek fairytale says a young girl named Arachne was a superb spinner and knitted the most gorgeous cloth. She dared the goddess Athena to a competition. When Athena saw Arachne’s stunning work, she ripped the cloth and hit the young girl. Disgraced, Arachne committed suicide by hanging herself. Athena regretted and transformed Arachne into a spider, so that she could whirl repeatedly and endlessly. Arachnida is the scientific name for spiders. It comes from the young girl in the famous Greek fairytale.

Although usually feared and disliked by people, spiders in fact make life easy for us by feeding on mosquitoes, flies, and locusts, thus saving our crops and eliminate the need for man-made insecticides which pose environmental problems. Besides, spiders are much less dangerous than people think they are; most spiders are keen to avoid interaction with people and will bite only when wounded or scared. Even poisonous spiders are rarely as dangerous as popular myths would have us believe: though black widows are poisonous, and their bites painful, they rarely kill people. If handled properly and quickly the adverse consequences of a black widow’s bite typically diminish in a few hours, and, after a couple of days’ rest or cessation of activities, the victim will fully recuperate [1].

There are countless features of spiders. But their silk is exceptionally unique and this article covers its various aspects.

Spider silk

Biomaterials, having developed over millions of years, frequently surpass man-made substances in their properties. Spider silk is an exceptionally stringy biomaterial which is made almost completely of substantial proteins. Silk fibers have stretchy powers similar to steel and some silks are practically as elastic as rubber on a weight-to-weight basis. In uniting these two properties, silks disclose a hardiness that is two to three times that of artificial fibers like Nylon or Kevlar. In addition, spider silk is also antimicrobial, hypoallergenic, and completely biodegradable [2].

The power of spider silk, so fragile in manifestation, is astonishingly great. A filament can be outstretched as much as one half its normal length before breaking, and has a tensile strength exceeded only by fused quartz fibers. Fine fibers are sturdier than others, the power to some degree depending on the velocity with which they are pulled out of the spider’s body. The higher the speed, the superior the strength.

Most of the silken fibers are not single fibers but are made up of two or more strings. A thread may be as fine as a millionth of an inch in width but, frequently, it is ten or twenty times as dense, and the assemblage of these threads unsurprisingly creates larger threads of a diversity of thicknesses. Furthermore, some threads are gluey whereas others are not.

Scientific research demonstrates that a single thread of spider silk, thick as a pencil, could stop a 747 Jumbo Jet in flight, and that on an equivalent footing, the spider’s silk is stronger than steel, per unit weight. It has been shown that the dragline silk of the golden orb spider is one of the planet’s hardest threads.

Spiders employ silk for webs, but also for trap lines, draglines, ballooning lines, for egg pouches and nursery nets, for compartments in which to sleep through winter or to copulate, and for entrapping and wrapping their victims. Silk for all these objectives is not accomplished with one kind of gland; there are at least seven distinct kinds. A few distinctive spiders have as many as six kinds and probably have more than six hundred independent glands; others have fewer than this [1].

Mechanism behind the formation of spider silk

A batch of scientists headed by researchers from the RIKEN Center for Sustainable Resource Science (CSRS) have scrutinized spider silk and discovered that a formerly undiscovered organizational constituent is critical to how the proteins form into the beta-sheet conformation that gives the silk its extraordinary power [3]. If humans can cultivate equivalents to spider silk, they could be applied in industrial and medical applications. It is well-known that the beta-sheets in spider silk are significant to its strength, but how the sheets are created is scantily comprehended, making it difficult to produce synthetic variations. It is hard to comprehend the process: the silk is originally produced as soluble proteins, which very swiftly crystalize into a solid form.

To explain this, the CSRS scientists obtained silk proteins using genetically altered bacteria that can generate silk from a golden orb-web spider (Nephila clavipes) and then executed multifaceted examinations of the soluble proteins. They discovered that the reiterating area is comprised of two designs – unsystematic spirals and a design called polyproline type II helix. Their investigations confirmed that the polyproline type II helix is critical for the creation of the stiff construction, which can then be rapidly converted into beta-sheets, letting the silk be swiftly intertwined. Fascinatingly, it was discovered that pH – which is supposed to be significant for the molecular exchanges of the N- and C- terminus areas – does not play a significant role of the foldup of the recurring areas, and that it is rather the elimination of water and mechanistic forces through the silk gland.

According to Keiji Numata, who is a project leader of JST ImPACT and led the research group, “Spider silk is a wonderful material, as it is extremely tough but does not contain harmful substances and is readily biodegradable, so it does not exert any harmful load on the environment” [4]. Numata hopes that this discovery may lead to the production of artificial silk that will prove useful for society.

Analysis of silk

The silk itself is a material identified as a “scleroprotein.” When created in the glands it is a fluid; only when dragged outside the body does it solidify into thread. Once it was believed that contact with air produced the toughening, but it currently looks that the drawing-out activity alone is accountable for the change.

To carry out the exertion done by the glands, a spider is armed with spinnerets, usually six in number. These are as accommodating as fingers; they can be prolonged, compacted, and overall be applied like human hands. In the “spinning field,” where the spinnerets are congregated, single threads are joined into numerous compound threads, and some of the dehydrated threads may be covered with a gluey substance. Thus, a completed thread may be thin or thick, dry or sticky. It may also have the look of a bead-trimmed necklace. For the last kind, the spider spins rather unhurriedly and, drawing out the gluey thread, lets it go with a jolt. The liquid thus is organized in beads spread out lengthwise across the completed line.

The strand known as the dragline may be understood as a spider’s “life line” because it performs as a lifeguard in all kinds of situations. The dragline goes along with the spider, no matter where or how far it journeys, winding out from spinnerets at the back of the body. It forms a portion of the building of webs, it grips its tiny builder firmly in problematic places, and it helps in absconding from adversaries. When a spider is inactive in a web, the dragline enables a rapid descent and escape. It allows energetic chasing spiders to jump from buildings, cliffs, or any tall position with absolute security. [1]  

Benefits of spider silk to us

The silk of the silkworm could be very profitable and marketable. There are, however, challenges. One is the changing thickness of a spider’s strand; the other is that it doesn’t well endure the interweaving process. Housing and feeding large numbers of silkworms is not difficult. But housing and feeding large numbers of spiders? There are enormous difficulties.

Native inhabitants of New Guinea have used spider silk in a variety of conditions. They make fishing nets, traps, and such objects as bags, headdresses that will keep away rain, and caps. These are not formed from single threads but from tangled, warped threads. The aboriginals of North Queensland, Australia, look to spiders for their angling supplies.

Spider silk has been valuable to the manufacturers of such complex instruments as astronomical telescopes, guns, and engineers’ levels. The threads, being exceedingly fine but nonetheless robust, are outstanding for sighting marks. Throughout the Second World War, there was a significant demand for spider thread for surveying and laboratory instruments. Black widow spiders were utilized for the manufacture of this silk.

One drawback to the use of spider silk in industry is that it might slump in a moist environment. To overcome this problem, strands of platinum or etching on glass plates take its place in such instruments as periscopes and bombsights. [1]

Spider’s silk also might have healing properties. Due to its antibacterial properties and because the silk is abundant in vitamin K, it may be efficient at clotting blood. Because of the problems in obtaining and handling extensive amounts of spider silk, the largest known piece of cloth made of spider silk is an 11 by 4-foot (3.4 by 1.2 m) fabric made in Madagascar in 2009. Eighty-two persons labored for a period of four years to gather over one million golden orb spiders and extract silk from them. [5]  

Applications of spider silk

As mentioned, human beings have been using spider silk for thousands of years.

The manufacture of contemporary synthetic super-fibers such as Kevlar (bulletproof material) includes petrochemicals, which adds to pollution. Kevlar is also strained from concentrated sulphuric acid. In comparison, the manufacture of spider silk is totally ecologically sustainable. It is created by spiders at ambient temperature and pressure and is strained from water. Furthermore, silk is totally biodegradable. If the manufacture of spider silk ever becomes industrially practical, it could be a substitute for Kevlar and be used to create a varied extent of articles such as: bulletproof vests, wear-resistant lightweight clothing, ropes, nets, seat belts, parachutes, rust-free boards on motor vehicles or boats, biodegradable bottles, bandages, surgical thread, artificial tendons or ligaments, and backings for weak blood vessels. [6]

Synthetic spider silk [5]

Duplicating the multifaceted settings needed to make threads that are similar to spider silk has been difficult to both research and manufacture. Through genetic engineering, Escherichia coli bacteria, yeasts, plants, silkworms, and animals have been utilized to produce spider silk proteins. Yet, these synthetic threads have diverse, simpler features than those of a spider. Manmade spider silks have lesser and unsophisticated proteins than natural dragline silk, and have subsequently half the diameter, strength, and flexibility.

One tactic is to remove the spider silk gene and utilize additional life forms to generate the spider silk. Canadian biotechnology company Nexia effectively produced spider silk protein in transgenic goats that passed the gene for it; the milk made by the goats comprised noteworthy amounts of the protein: 1-2 grams of silk proteins per liter of milk. To make spider silk, Nexia utilized damp whirling and pressed the silk protein across minor extrusion cavities in order to mimic the performance of the spinneret, but this process was not adequate to duplicate the sturdier characteristics of innate spider silk.

In March 2010, investigators from the Korea Advanced Institute of Science and Technology was able to produce spider silk by means of the bacteria E. coli, altered with definite genes of the spider Nephila clavipes. This tactic removes the necessity of milking spiders.

It should be noted that the manufacture of spider silk is not easy and there are intrinsic difficulties. First of all, spiders cannot be cultivated like silkworms since they are flesh-eaters and will merely eat each other if in proximity to each other. The silk produced is very slight, so 400 spiders would be required to make only one square yard of cloth. The other problem is, silk also toughens when subjected to air, which makes working with it problematic.

A different tactic is to study how spiders whirl silk and then replicate this process to make artificial spider silk. The silk itself would also have to be synthetically produced. Chemical production of spider silk is not feasible at present due to the absence of information about the makeup of silk. Randolph V. Lewis, Professor of Molecular Biology at the University of Wyoming in Laramie, has introduced silk genes into Escherichia coli bacteria so that the recurring sections of spidroin 1 and spidroin 2 efficaciously come to form. Others theorize about the likely gene introduction into fungi and soya plants. It may also be possible to modify the silk genes for precise intentions.

Why a spider’s house is the frailest of houses

Spider silk is stronger than steel, but the Qur’an (29:41) states that the flimsiest of houses is the spider’s house. The per unit weight of the dragline silk of the golden orb spider is one of the world’s hardest fibers. Webs are combinations of many kinds of spider silk, all able to be produced by the same spider. The web radials are strong, but the somewhat feebler circumferential (quasi-circular concentric) fibers are flexible and gluey to absorb the energy of a flying insect and hold it in place. The strongest of all is the fiber, which the spider uses for transport, the dragline silk. In summary, the spider fabricates both sturdy as well as feeble fibers and the web it weaves to catch flying insects is weaker; this may be the reason why it is referred to in the Qur’an as the “frailest” of houses.

Conclusions

Scientists are foreseeing many potential uses for biosilk. Textile usages are noticeable one. The flexibility and potency of prevailing merchandises such as spandex and nylon have to be improved. Since it is lightweight, hardy and flexible, biosilk may also have uses in satellites and aircraft. More prominently, the new group of progressive things that spider silk investigation may cause has the prospective to alter our lives in innumerable manners that we can barely imagine. More than 72 years have passed since the inventions of Wallace and Carothers that gave the world nylon that led us into the age of polymers. Artificial spider silk may help produce super-performing clothes of the future. Earthquake resistant suspension bridges hung from cables of synthetic spider silk fibers may someday be a reality. [1]

References

1. Syed, I. B. : Spider Silks http://www.irfi.org/articles/articles_1_50/spider_silks.htm
2. Romer, L and Scheibel, T.: The elaborate Structure of spider silk, PRION, Oct-Dec. 2(4) 154-161, 2008. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658765/
3. RIKEN Center for Sustainable Resource Science (CSRS). Scientists discover key mechanism behind the formation of spider silk. Materials Science. May 29, 2018, https://phys.org/news/2018-05-scientists-key-mechanism-formation-spider.html

4. Nur Alia Oktaviani, Akimasa Matsugami, Ali D. Malay, Fumiaki Hayashi, David L. Kaplan, Keiji Numata, “Conformation and dynamics of soluble repetitive domain elucidates the initial β-sheet formation of spider silk”, Nature Communications, 10.1038/s41467-018-04570-5 https://en.wikipedia.org/wiki/Riken
5. Service, Robert F. (18 October 2017). “Spinning spider silk into startup gold”. Science Magazine, American Association for the Advancement of Science. Retrieved 26 November 2017. https://en.wikipedia.org/wiki/Spider_silk
6. Vivienne Li, University of Bristol, Spider Silk and Venom. Molecule of the Month – July 2002. http://www.chm.bris.ac.uk/motm/spider/page4.htm

Jakus AE et al. Hyperelastic “bone”: A highly versatile, growth factor-free, osteoregenerative, scalable, and surgically friendly biomaterial. Science Translational Medicine. September 2016.

Bone implantation surgery is both challenging for doctors and a painful process for patients, especially children. It usually requires either harvesting existing bone tissue from elsewhere in the body, or using metallic implants. While these approaches may work for adults, they are not a permanent solution when used for growing children. In a recent study, scientists reported a 3D printable ink that forms a synthetic bone implant and induces bone generation and growth. This biomaterial is composed of a mix of 90% hydroxyapatite, a calcium mineral found in human bone, and 10% biodegradable polymer, which is commonly used in medical applications, including sutures. The key feature of this new hyper-elastic biomaterial is its ability to create porous structures where blood vessels and other cells can infiltrate to create a scaffold. Animal studies showed that when stem cells are placed on these scaffolds, they turn into bone cells and initiate the regeneration process. Additional factors can also be easily integrated into the biomaterial, such as antibiotics to prevent post-surgery infections or growth factors to further enhance the regeneration process. The advantage of 3D printing technology will enable doctors to create personalized bone structures with custom shapes and properties for each patient.  In the near future, hospitals with biomaterial and 3D printing facilities may revolutionize the field of craniofacial and orthopedic surgery.

Gene behind “sixth sense” discovered

Chesler AT et al. The Role of PIEZO2 in Human Mechanosensation. The New England Journal of Medicine. September 2016

Close your eyes and bring your finger to your nose. It’s an easy task for almost all of us, isn’t it? Awareness of the position of one’s body in space is called proprioception, also commonly known as the “sixth sense.” A recent study describes the cases of two patients who lack proprioception. These patients could not walk, keep their balance, or even touch their noses when blindfolded. Genetic analyses revealed that both patients had mutations on a gene called PIEZO2, suggesting that this gene is responsible for the sense of touch and proprioception in humans. Further investigation of the PIEZO2 gene showed that it controls mechanosensation by generating nerve signals in response to any force touching the skin, thus allowing us to sense the touch. The patients seem to compensate for a lack of proprioception by relying primarily on vision. While these patients have non-functional PIEZ02 genes, there is an intriguing possibility that there could be other variations of this gene in the human population, which may generate a spectrum of symptoms from superior athletic performance to clumsiness, depending on the P

Before anasthesia, even routine surgeries were painful and dangerous. Its advent has allowed for amazing advances in public health and patient safety.

Humanity has faced various kinds of health problems throughout history, and will be facing them until the end of time. Even someone who has not yet suffered from an illness, will almost certainly suffer from one in the future. Let’s take a moment to reflect on all the people who are currently undergoing treatment at hospitals in the hopes of curing an illness.

From time to time we visit close friends and relatives who have undergone such operations. We wish them health and talk with them a little. We ask them how the operation felt, how many stitches they have. They usually say, “They injected me with something and I don’t remember the rest.” Then they may show us their gall bladder, wrapped in gauze, or their kidney stone, which was removed. Have you ever pondered how it is possible not to feel any pain during these kinds of operations, or how it is possible not to remember anything?

Surgical practices have advanced so much in present times. Heart, liver, and kidney transplants are now commonplace, as are finger and arm reattachments. Anesthesia, which makes all of these operations possible and painless, is a great blessing. Even the small and simple surgeries performed just 150 years ago were very difficult for surgeons – not to mention very painful for patients.

In his famous book on physiology and treatment, The Canon of Medicine the renowned 10th and 11th century scholar, Avicenna (Ibn-i Sina) (980-1037), defines anesthesia as, “a numbing and a cooling remedy.” He gives pathophysiological commentary on the influences of anesthetics and analgesics, and summarized painkilling methods as following:

1. A mixture prepared from linseed and dill should be applied to the area of pain.
2. Decreasing the sensitivity of the area of pain by increasing the moisture of the area, or providing narcotics for sleep.
3. Providing cooling and analgesic and anesthetic medicine.

Biruni, another Islamic scholar from the 11th century, documented his work with analgesic and anesthetic medicine. One of his writings recommends boiling the root tubers of henbane, Mandragora, horned poppy (Glaucium flavum), and Iris, together with the attar of roses and vinegar.

In his pharmacological works of the 12th and 13th centuries, Samarqandi recorded the analgesic, sedative (calming), anesthetic, and hypnotic effects of opium, mandragora, henbane, lettuce, beaver testicles, aloe vera, and coriander.

During the end of the 17th century, in Italy, anasthesia was performed by preventing the patients from breathing until they lost consciousness, and then immediately performing surgery on the patient who had fainted. This was called the asphyxia technique. The surgeries performed were relatively easy, such as the cutting of an arm or leg. The surgeon who was fast was considered the best, because patients could wake up during the surgery – that is, if they survived the procedure.

Another interesting anesthetic technique was making the patient lose consciousness by hitting them on the head. The hitting had to be done, “Hard enough to break the shell of an almond but gentle enough not to destroy its seed.” However, a bitter truth is that many patients were killed during this process.

Many have suffered the consequences of the absence of anesthesia in the past. Dr. Warren, a professor at Boston’s Massachusetts General Hospital in 1846, had placed his operating room on the very top floor of the hospital in order to avoid disturbing others with the screams of the suffering patients. One day, while examining one of patient’s tongues with pliers and a scalpel, he pulled the tongue of the patient without warning, and cut off his tongue with the scalpel. Afterwards, without hesitation, he cauterized his patient’s tongue with a hot iron. Dr. Warren observed the screaming, moaning, and suffering of the patients with no sign of emotion. He did not seem disturbed, and this was the exact attitude he needed in order to perform his duty. However, years later when enough advancement was done in the area of anesthesia, he couldn’t hold back his tears during the first operation that was performed with anesthesia.

Surgeries performed without anesthesia were hard on surgeon and patient alike. During his studies, the English gynecologist, Doctor James Young Simpson, fainted while cutting off a breast and considered quitting being a surgeon. Prof. Dr. Robert Liston was a famous surgeon at London University College. Dr. Liston had a reputation for being rude, arrogant, and strong. But he had no choice: he was forced to cut off a leg in 28 seconds, as anesthesia was not yet developed.

As can be seen from these examples, the absence of anesthesia, and the incredible suffering of the patients, pushed surgeons to be incredibly fast and emotionally insensitive. This period of time defined surgeons as strict, insensitive, and despotic. This went on until 1846, when William Thomas Morton performed the first surgery with anesthesia.

Since then, anesthesia has made surgeries much easier for all involved. Today, the definition of general anesthesia is total or partial loss of sensation in a human or animal body before surgical intervention.

Usually, anesthesia is performed by injecting medicine into the blood, or by making a patient breath an anesthetic gas. First, the patient loses consciousness, and then, with the help of muscle relaxants, the patient is put in a state of paralysis. Artificial respiration is performed until the end of the operation with the help of breathing machines called ventilators. For this purpose, an endotracheal tube is inserted in the windpipe of the patient and they are hooked to an anesthesia machine. This feeds oxygen, air, and the anesthetic gas to the patient. The anesthesia doctor controls the patient’s breathing, blood pressure, and heart rhythm, as well as other various, vital parameters, and the fluids that will be fed to the patient throughout the surgery. By doing this, the continuity of the anesthesia is made possible. When the surgery is over, the anesthetic drugs are no longer fed to the patient. When the muscle relaxants lose their effect and breathing returns to normal, the endotracheal tube is taken out and the patient is taken to another room to wake up. This is where the patient opens their eyes; it’s almost like a re-birth.

The chemicals in cannabis, opium, and coca were the essence of the first drugs used for general anesthesia; they are still being used, partially, in modern times. These chemicals, and some synthetic chemicals like them, are used for anesthesia and can be used after surgery in order to soothe pain. Most of our contemporary drugs are mostly synthetic, and they require many years of difficult education to be properly handled. It takes four years of additional education, after medical school, for a surgeon to become proficient with anesthetics.

Medical research done in the last two centuries about the dosage and quantity of these chemicals has advanced the practice of anesthesia incredibly. All this research provides a very good answer to why drugs have been created. While surgeons use the chemicals extracted from cannabis, opium, and coca, and from the synthetic chemicals like them, as a service to humanity, it is really hard to understand why some ill intentioned people use them for the detriment of human health.

Even though Kant has very original insights that opened new gateways in the history of philosophy, his so-called “critical philosophy” is not devoid of defects. This article aims to present Kant’s account of causation and critically evaluate it.

Kant’s famous remark about his awe for “the starry heavens above me, and the moral law within me,” which is written in his gravestone, shows his orientation in philosophy. While he was interested in explaining the features of the universe and the nature of our theoretical knowledge, he did not ignore the practical aspect of our life that concerns with how to act in the right way. That is to say, ethics and natural science were main disciplines Kant tried to understand. However, this paper examines his analysis of theoretical knowledge and the natural science by focusing on his account of causality.

An introduction to Kant’s “critical philosophy”

Before Kant, there were two important traditions in modern philosophy: rationalism and empiricism. On the one hand, the rationalists assumed that we could obtain knowledge of the world by trusting in the power of our minds. Kant considered them to be dogmatic in the sense that they dogmatically assumed this idea without examining the nature and limits of our minds so as to see whether we can really achieve this goal or not. On the other hand, the empiricists usually distrusted the power of the mind in its attempt to know the world, and in its most extreme case, in Hume, it led to skepticism. In response to these two approaches, Kant suggested to examine critically the nature and limits of the mind and see to what degree we can have knowledge at all. This is called “critical philosophy.”

For Kant, our minds are not passive receivers of representations like mirrors. A normal flat mirror reflects the image from an object as if it is the same except in a two-dimensional way. It was a common attitude among philosophers before Kant to treat the mind like a mirror. The mirror does not change the form of the object. Likewise, the mind does not affect or change the form of the objects, it just receives them. However, Kant changed the whole picture. He treated minds as active filters. Whatever is reflected on it is shaped in a certain way. On this view, the mind is like a concave or convex mirror, or colormatic glasses but it is not like a flat mirror.

According to Kant, the mind has three faculties with different functions. These faculties are sensibility, understanding and reason. Through sensibility we get the raw material of experience. This material is structured and shaped by space and time which are not outside the mind but are the pure forms of the faculty of sensibility. What we get through this faculty is called “intuition.”

The faculty of understanding provides us with concepts, especially with “the pure concepts,” or categories, of which there are twelve in total, and are used in organizing the intuition. In brief, what is reflected on the mind as coming from the world is structured by the a priori forms of intuiton (space and time) to which the twelve categories of mind are applied.

Kant’s postulation of the mind as an active factor in obtaining knowledge is considered to be “the copernican revolution” in philosophy. Kant has a formula which depicts his system very well: “Thoughts without content are empty, intuitons without concepts are blind.” In order to have understanding, we should both have intuition and concepts. These two conditions should be fulfilled for a genuine and reliable understanding. First, concepts without intuiton do not give us understanding; we can just think about them and never be sure whether they are something about real or not. According to Kant, concepts such as soul, God, and free will are ideas to which no intuition corresponds. Second, if there were no ordering role of the mind, all the information we got from the world would be chaotic. For instance, we would not be able to identify a certain individual as a human being, an animal of a different sort or even as an object, because we lacked an ability to order and classify the information. Therefore, according to Kant, the world appears to us differently from as it is in itself due to the ordering character of the mind.

Kant calls the world as it appears to us “phenomena” and the world in itself “noumena.” The latter is beyond the limits of the legitimate realm of theoretical knowledge. We cannot understand it, and we cannot theoretically know anything about it: we can only think about it. Ideas such as those of God and free will are directed toward the nounemal realm. They belong to the faculty of reason and have a regulative role in ordering and unifying our experience. However, they are empty according to Kant. That is to say, there is no corresponding intuition to them in our experience. Thus, we cannot decide whether they really exist or not by theoretical knowledge. This conclusion of Kant’s critical philosophy may suggest an agnostic position towards God, (actually it led many people to become agnostics) according to which human beings can neither affirm nor deny the existence of God. However, Kant thought that he found a reason for believing in God in another domain, namely in practical reason and knowledge. Nevertheless, Kant’s attempt to show the illegitemacy of theoretical knowledge regarding neumena undermines itself. This can be seen especially in his analysis of causality.

Synthetic a priori truths

Kant takes mathematical science and natural science for granted. He accepts them as successful sciences and tries to understand the conditions under which they are possible. His conclusion is that these sciences can be grounded only on “synthetic a priori judgments.” There are two important conceptual distinctions here: the analytic-synthetic and the a priori-a posteriori. The former is a semantic distinction, the latter is epistemological. A statement is analytic if its predicate-concept is included in the subject-concept, otherwise it is synthetic. The proposition that all black cats are black or that bachelors are unmarried is analytic. A black cat is black, the predicate is embedded in the subject here. And bachelors are by definition unmarried because a bachelor is a single male. However, the color of my cat is not included in its definition. A priori judgments are known independently of experience whereas a posteriori ones are known by appealing to experience as a justification. We know that everything is identical to itself without any experience. But we need some experiential evidence to affirm the statement that the Morning Star is identical with the Evening Star. It was a scientific discovery that those stars were actually the same, namely Venus.

For Kant, all analytic judgments are a priori. He also claims that there are synthetic a priori statements. This is a bit unusual because we normally know synthetic statements by experience. How can we know a statement a priori if its predicate is not included in the subject? Kant explains the possibility of such judgements by appealing to the mind’s role in shaping experience. According to him, by applying the categories to intuition, we put what is in our minds into our experiences. So, “we can cognize of things a priori only what we ourselves have put into them.” In other words, the categories shape the experience and we know that aspect of experience a priori since it belongs to us. The conceptual distinctions presented so far enable us to understand Kant’s account of causality better.

Causality

From a historical point of view, Kant’s account of causality was a response to Hume’s scepticism about causation. Let us first see what Hume said about this issue. Hume points out that we only observe correlated events in nature, and that there are some regular correlations and some irregular ones. For instance, we always observe that lightning precedes thunder. On the basis such regular correlations, we infer that the events in question are also causally related. That is to say, lightning causes thunder. However, according to Hume, we never observe causation between events. What is observed is just that two events are correlated in a regular manner. Causation is what our mind is inclined to infer when faced with such regularities. Causal links are produced by the human mind as subjective mental operations. So, there is no objective causality between events: it is our subjective interpretation of the regularity between them.

If we consider the fact that electrical charges are regarded as the common causal factor behind lightning and thunder by contemporary scientists, we can appreciate what Hume said. We do not observe causal links. Perhaps, sometime in the future, scientists will propose another physical factor as the cause for thunder, lightning and maybe for electical charges. Since we do not observe causal links, we can never be sure about what causes what. Hume extends this skepticism so far that nothing really causes anything else. There is no objective causation; there are just correlations in our experience. In other words, he also denies the objectivity of the universal causal principle, namely that every effect or event must have a cause.

As a response, Kant distinguishes two different levels in analysing causation. On the one hand, he tries to prove the objectivity of the universal principle of causality. Kant is aware of the difficulty of proving it on the basis of experience. Such a universal principle cannot be based on experience. Kant considers this univeral principle as a synthetic a priori truth. It is valid for anything we experience because all our experience is shaped by the category of causality. He formulates this principle in the following way: everything that happens presupposes that which it follows in accordance with a rule.

According to Kant, the phenomena consisting in irreversible sequences indicate the causal order. As an example of irreversible sequence, he mentions the sequence when we look at a ship moving down the river. In this case, what we apprehend is an objective process. And its order cannot be arranged otherwise than in this very succession. So, when we watch the ship’s departure, the order in which our visual states occur is not up to us. As a conclusion, Kant argues that in irrevesible cases, the apprehension of one perception which occurs necessarily succeeds that of the other which preceded according to a rule called “the law of the connection of cause and effect.”

On the other hand, Kant’s analysis of irreversible sequences does not suggest anything about particular causal relations. A particular sequence of irreversible representations does not enable us to identify the cause of the event in question: it only indicates that the event in question must have a cause (in the sense that some other event precedes it), even if we do not know what this cause is. Kant expresses this point by saying that “Everything in nature, as well in the inanimate as in the animated world, happens or is done according to rules, though we do not always know them….”

While there are some ambigious passages indicating as if Kant has identified some necessary causal links between particular events (such as that the sunshine caused the warmth of a stone), those passages should be interpreted under the light of this general statement here. The reason simply is that Kant aims to exemplify his view of causation in such contexts rather than identifying some particular causal links.

A fundamental problem with Kant’s analysis of causality

As we have seen, Kant treats the universal principle of causality as a synthetic a priori truth. In doing so, he limits causal ascriptions to the phenomenal realm because it is the phenomenal realm not the noumenal realm, which is shaped by our minds. So, according to Kant causal talk about noumena, things in themselves, is not legitimate and does not give us theoretical knowledge.

However, the question that should be answered in this regard is if the human mind interacts with noumena. If so, how does it interact? In some passages, Kant seems to consider noumena to be an empty and limiting concept. We cannot know anything about this realm (even whether or not noumenal objects such as free will, soul and God exist), therefore it is just a heuristic device indicating what is beyond our theoretical knowledge. Thus, we cannot say anything about the relationship between the mind and noumena, because noumena are beyond our understanding. Otherwise, anything we say can only be an illegitimate speculation.

Nevertheless, such passages do not represent Kant’s whole philosophical outlook. As a fundamental aspect of his critical philosophy, Kant assumes that our experience is shaped by us but not totally created by us. There is an external element to experience that is independent of us. He must accept that there are noumenal objects even though we do not know what they are. They are not just conceptual tools formulated to define the phenomenal realm. In fact, there are several passages in which Kant explicitly ascribes causal efficiency to the noumenal realm.

For instance, when Kant distances himself from the idealist philosophers who claim that everything we perceive is mind-dependent and there is no objective reality outside the mind, he claims that “there are bodies without us, that is, things which, though quite unknown to us as to what they are in themselves” and that we know them “by their representations which their influence on our sensibility procures us.”

As another example, this time regarding the free will of human beings, Kant thinks that human beings are free with respect to the noumenal realm but under causal determination with respect to phenomenal realm. When he tries to account for moral responsibility, he presents the free will as having its own causal power to be able to appropriate particular human actions. The following is an explicit remark: “The will is a kind of causality of living beings so far as they are rational.”

As it is clearly seen, Kant is forced to accept that the realm of things in themselves (noumena) causes the realm of appearances (phenomena) and this is exactly what undermines the very foundation of his critical project as limiting theoretical knowledge to phenomena.

Conclusion

Kant certainly has an insight in making a distinction between phenomena and noumena; however, his way of distinguishing these two realms undermines his own critical philosophy. There is a similar distinction made by Muslim theologians between dhahir (phenomena) and batin (noumena). In their case, categories of causality and existence for instance are legitimately applicable to noumenal realm, but they argue that we do not know how they are applicable. According to them, for instance, we know that God exists but we do not know how He exists. His existence is quite different from our existence. As Descartes says: “A finite mind cannot grasp [adequately] God, who is infinite. But that does not prevent [the finite thinker] having a perception of God, just as one can touch a mountain without being able to put one’s arms around it.” As a conclusion, Kant’s distinction between phenomena and noumena should be improved so that it enables us to ascribe existence and causality to the noumenal realm even in a minimal sense.

Original Article: Gibson, D.G. et al., Science Express (2010).

A team of genome researchers at the J. Craig Venter Institute in the U.S recently announced that after almost 15 years of work and with a budget of $40 million, they had finally built the first bacterial strain with a completely synthetic genome. In the study, researchers chopped the genome of Mycoplasma mycodies into 1,000 pieces in the computer, chemically synthesized these fragments and assembled them into an artificial chromosome in yeast cells. The reconstructed artificial genome was subsequently transferred to a closely related bacterium Mycoplasma capricolum, whose genome was removed. Remarkably, the strain with the artificial genome was able to guide the protein machinery of the host cells, produce the necessary enzymes and macromolecules for a bacterium to survive and most importantly to grow and divide. Team leader Prof. J. Craig Venter, best known for his pioneering efforts in human genome mapping project, commented on their findings as “we created a ‘synthetic cell’ and it is the first self-replicating species we’ve had on the planet whose parent is computer.” Many media sources also publicized the study as the first successful creation of the artificial life. As much as the scientific community agreed that the synthesis, transfer and retention of a functional synthetic genome is a breakthrough, most of the scientists have found Prof. Venter’s comments and the media’s reflection on the study to be somewhat of an overstatement. It would be quite unfair to call the new bacteria an example of “artificial life.” The synthesized genome was a copy of another living bacterium with slight modifications. The genome is a blueprint, whereas the proteins perform the actual cellular functions. This new approach shows that we can copy the book of cellular blueprints reliably but it brings no new parts to our inventory. Moreover, the synthetic genome had to be assembled in live yeast cells, processed with biochemical extracts from mycoplasma cells and finally transplanted into another (closely related) live cell. In other words, “natural life” was absolute prerequisite for the so-called “artificial life.” The generation of a fully functioning organism directed by machine-synthesized genome certainly represents a major step in our ability to manipulate large chunks of genetic material. It is clear that this study will positively influence many scientists, especially synthetic biologists, to try writing novel “synthetic” software to recruit the variety of organisms’ cellular hardware for solving various global problems like energy shortage or environmental pollution. However, the philosophical questions that probe the essence of life, like: “Can we reduce life to material? Is the human being ever going to be able to build a live cell from only a few chemicals?” will likely remain as major controversial issues for many years in the age of molecular biology.

2- Sharing the powers of Spiderman

Original Article: Vogel, M.J. & Steen, P.H., PNAS (published online before print on February 4, 2010).

The adhesive powers of Spiderman, jumping from one building to another and walking on the walls, attracted most of our interests. The recent invention of scientists from Cornell University brings this power from science fiction cartoons/movies to the real life. Inspired from a little creature, leaf beetle, which can stick to leaves by generating a force exceeding 100 times its body weight, these researchers designed a device which can stick to surfaces by using the adhesive powers of water. The device consists of a plate not thicker than a credit card with hundreds of tiny holes on it. The water is pumped through these holes, which builds liquid bridges between surfaces and thus generates a strong adhesive force. Simply pushing back the water un-sticks the device in a controllable and switchable manner. There are no solid moving parts nor any kinds of glue used in the system, and this makes device even more promising. The capabilities of the device are not at the level of the leaf beetle yet, but the inventors believe that it can be improved by building on the same principles. The system can potentially be used in many practical applications, such as robotics, and it can also be implemented into shoes and gloves allowing them to stick to surfaces. Accordingly, it is no longer improbable to imagine sharing the sticky-powers of Spiderman and walking on the walls very soon.

3- Igniting a Supernova

Original Article: Gilfanov, M. & Bogdan, A., Nature 463, 924 (2010).

upernova: the Rosetta stone that may help us put together the missing pieces of the cosmic jigsaw puzzle; one of the most energetic and most luminous explosions in the universe, putting out energies equivalent to what our sun could produce in 10 billion years. Yet the mechanism that produces these explosions still eludes us. Once our sun consumes its remaining fuel in another 5 billion years, it will shrink into a “white dwarf.” These compact stars are believed to produce subsequent explosions leading to supernovas if they reach beyond a critical limit of mass. One way to gain mass is to steal material from a companion star through an “accretion” process. Accretion was thought to be the most common means that might help push the mass of a white dwarf beyond the critical mass limit, until a recent study revealed that two clashing (in-spiraling) white dwarfs might be the missing fuse that ignites supernovas. German astronomers measured the X-ray flux of four nearby elliptical galaxies and the core of the Andromeda Galaxy to see whether the amount of X-rays from these galaxies are consistent with predictions based upon the accretion mechanism. Contrary to expectations, the observed X-rays were 2–3% of the amount that would have been produced if accreting white dwarfs were the primary trigger of supernova explosions. Hence, perhaps merging white dwarfs are more commonplace in the cosmos after all.

4- Strategy of bats finding their way

Original Article: Yovel Y et al., Science 327, 701 (2010).

Bats, dolphins, shrews and swiftlets use sound waves for navigation and hunting. They emit short sonar pulses and listen to the echoes reflecting back from solid objects. Microsecond differences in the arrival times of echoes are coded by detector neurons and used as a main cue for positioning objects in an environment. This phenomenon is known as biosonar. A recent study published in Science reveals one unknown part of this perfect sound processing strategy. The study shows that bats do not center the sonar beam on the target. Instead, they aim to match the maximum slope of the beam to the target in order to increase the signal-to- noise ratio. Around the sharp edge, small variations of the target position can be detected as a clear signal change in reflected sound intensity. Furthermore, the researchers showed that if the environment is very noisy, bats could bias this critical point to increase amplitude of the echoes. This powerful technique has already been employed by humans in engineering and used in various technological tools such as atomic force microcopy. Whether this strategy is used in general by other echolocating animals remains to be answered.

We inherit our hereditary characteristics from our parents. The basic unit responsible for inheritance in our body is the gene. More technically, a gene is a hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism. Genes are like words on the long string of DNA. The description of the fundamental process of synthesizing proteins from the information on genes is called the “Central Dogma.” According to this dogma, DNA is used to synthesize RNA, and in turn, RNA is used to synthesize proteins. Hence, this dogma dictates the link between genes and proteins. Proteins are actually a translated and three-dimensional version of the linear information stored in genes.

The Structure of DNA

DNA (Deoxyribonucleic acid) is our repository of genetic information. Although there are organisms such as RNA viruses that possess RNA (ribonucleic acid) as their genetic material, virtually all other living organisms inherit their genes through DNA. Hence, DNA is vital for the existence and perpetuation of life on Earth.

In a simple comparison, DNA can be likened to a sequence of letters where each letter is a single nucleotide, and the alphabet has only four letters: A, T, C and G. Although this alphabet is extremely small compared to those used in human communication today, we are still capable of capturing the vast size of human DNA with this analogy: Our DNA is composed of a sequence of nearly 3 billion (3,000,000,000) of these letters. What this means is that, if you were to type out your genetic code, you would have a 5,000-volume encyclopedia, with each volume containing 400 pages, and each page having 1,500 letters! But then, how do we even fit this formidable size of information in every single cell of our body? The answer lies in the astonishing folding, packaging and wrapping steps DNA goes through upon synthesis. Positioning nucleotides side by side, each DNA molecule would take up about 6 feet (~2 meters) of space. However, after all the packaging steps, DNA becomes compact enough to fit in not only a cell, but also in the microscopic nucleus of each cell.

Genes and the Human Genome Project

Unfortunate for our alphabet analogy above, the 3 billion nucleotides in DNA do not contain any spaces to let us know where each word begins and ends. The Human Genome Project accomplished the task of unraveling what these 3 billion letters are (each one is one of A,T,C and G) and this was a major achievement of humanity. However, it was not until then that we realized the real challenge DNA posed us: Where were the genes in DNA? In other words, how would we understand the words and sentences in this 3-billion string of letters? Apart from efforts to discover the DNA sequences of other organisms, it is not unfair to say that the interest and workforce once focused on the Human Genome Project has now almost completely shifted to this latter “real” challenge of discovering the genes in DNA.

How we wish life could be that easy! Just as completing the human DNA sequence made us realize that we did not know where the genes are, discovering some genes allowed us to understand that we would still be missing a major part of the picture even if we knew exactly where each gene was. Do we not frequently encounter instances in everyday life where one word means different things depending on context? So, is there any good reason to think that genes on our chromosomes will be any less complex? Unfortunately not. Quite to the contrary, the sense is growing that genes are actually far more complex and intricate than we originally thought. For one thing, a single gene may not cause an immediate effect, but may interact with a network of other genes to produce the final effect. Diseases that are caused by individual genes are actually very few, a famous example being cystic fibrosis. But diseases that are affected by the interaction of many genes are far more numerous and prevalent, for example, breast cancer, Alzheimer’s disease, Type 1 diabetes mellitus, multiple sclerosis and obesity.

This latter group of diseases is appropriately called “complex diseases.” Efforts are under way to decipher the intricate genetic and protein networks responsible for such diseases; however, there are so many (known and also unknown) variables that biologists have already called for help. Research problems such as complex diseases that require the interaction of biologists, mathematicians, computer scientists and statisticians alike have led to the advent of the currently very popular field of “Systems Biology.” Viewing the cell as a large factory, this field aims to understand all molecular networks and interactions that make up the very sophisticated machinery in living systems. After deciphering how cells operate flawlessly as a complex system, humans will be better able to discover causes of diseases, and will also be in a much better position to manipulate cells to cure diseases.

The idea of manipulating cells and cell components such as genes and proteins has actually led to “Synthetic Biology,” which is, in essence, the engineering approach to Systems Biology. Synthetic biologists try to engineer gene and protein networks in the cellular machinery to program cells for synthesizing custom-tailored molecules. This can be in the form of redesigning or producing mass amounts of existing molecules, or synthesizing nonexistent molecules that have medical or other potential uses. The overall significance of the field can be well understood by the following quote from one of the pioneers of the field, UC Berkeley professor Jay Keasling: “(Synthetic biology is) doing for biology what electrical engineering did for physics and what chemical engineering has done for chemistry.”

One example of synthetic biology comes from Jay Keasling’s lab. In collaboration with the Gates Foundation and OneWorld Health, the first nonprofit pharmaceutical in the US, Dr. Keasling’s lab is engineering a new metabolic pathway in E.coli to produce the precursor to artemisinin, currently the most effective treatment for malaria. The prospects include a drastic drop in cost, from dollars to dimes. Moreover, success in redesigning a metabolic pathway in bacteria holds great promise for reproducibility for other similar pathways important for the pharmaceutical, cosmetics and food industries.

Genomics vs. proteomics

Molecular biologists, today, are inundated with neologies ending with the suffix “-ome” and “-omics.” The consequence is that the expression “–omics” craze has found its place in the everyday language of these scientists. Basically, the suffix “-om-” refers to a totality of some sort. All the genes considered as a whole in an organism’s cell are called the “genome, and similarly all the proteins this genome can synthesize are referred to as the “proteome.” “Genomics” and “proteomics” refer to the study of the relevant “-ome,” as opposed to studying genes and proteins one by one.

Even though there exist so many –omics words in the literature these days, genomics and proteomics remain the most popular and useful ones. Proteomics can be thought of as the natural successor to genomics because it is fundamentally the next level of complexity after genomics. While scientists explore gene networks and their interactions in genomics, proteomics involves the study of all the proteins and their interactions in the cellular machinery of an organism. Unfortunately, the next level of complexity does not mean “linearly more complex” in this case; studying networks of three-dimensional molecules is an immensely more daunting task than studying those of one-dimensional DNA sequences. However, luckily for us, scientists are up to this challenge. Yet again, we observe a shift in focus in the scientific community from genomics to proteomics.

The main motivation for this shift can be roughly understood with an analogy from marketing or another one from military warfare. In the former, if you want a better marketing strategy for your product, you should target end-users first and foremost. Understanding behavioral patterns and preferences of end-users is much more important than understanding likes of your vendors, because eventually it is the end-user who will determine the demand for your product. In the latter analogy, we think of an army of soldiers who receive orders from a general commander; however, these orders can later be modified or completely annulled by orders from other commanders still in the hierarchical order. If you think about how reliable and informative knowing the orders that each soldier has received from the general commander is going to be, you will understand how useful it will be to have information on genes without supplementary information on proteins. Gene products, either RNAs or proteins, may undergo some steps called “post-translational modification” that are not completely understood, and worse yet may not be completely deterministic (implying random factors).

So, with the help of the analogies mentioned above, we can reason that the shift in focus of the scientific community from genomics to proteomics is mainly due to the fact that biological functions are carried out, not by DNA or genes, but by proteins and (although much less frequently than by proteins) by RNA molecules. For medical and other practical purposes, it is more important to acquire information on the proteome rather than the genome. This, of course, is not to suggest underestimating the importance of the genome. The genome preserves its significance as the origin and source of genetic information. It is just not as beneficial to think about the genome without looking at the final product, that is the proteome.

Conclusion

The completion of the rough draft of the Human Genome Project in 2000 marked the end of the Genetic Era and paved the way to the Genomic Era. The breakthroughs that have taken place since this cornerstone event have been breathtaking, awe-inspiring and maybe even hard to catch up with. The Genomic Era had given birth to different fields in a span of few years, and the biological scientific community has had to shift its focus from genomics to proteomics even without having sorted out the puzzles of the genome. The advent of the “-omics craze” was probably a by-product of this shift because suddenly each sub-field of molecular biology had to adapt a holistic approach in its explorations. Investigating a single entity, whether it be a gene or a protein or another molecule, quickly became stigmatized as “obsolete.”

This transition to a holistic approach has resulted in the interaction of biologists with scientists from quantitative fields such as mathematics, statistics and computer science. These interactions gave rise to truly interdisciplinary research fields such as systems biology, synthetic biology and computational biology. More and more scientists today believe that competence in the future will rely on incorporating expertise from these different fields. With each new discovery, realizing the level of complexity and the intricacy in the design of our body leaves us in true awe. Moreover, these discoveries only make it easier for us to grasp how little we know about the miraculous design of biological systems. On the other hand, this awareness makes us even more motivated to delve into scientific efforts because understanding the science behind creation takes us directly to the understanding of our Creator.

Jason Newfoundland is a PhD candidate in Bioinformatics at University of Michigan.

Notes

1. http://www.answers.com/topic/gene?cat=technology
2. This amazing process is demonstrated in this link: http://www.dnai.org/text/mediashowcase/index2.html?id=556
3. Synthetic Biology: Change on the Horizon, Karsten Temme, http://no.oneslistening.com/277
4. A glossary for –omics words exists at http://www.genomicglossaries.com/content/omes.asp

Vitamin basics

Vitamins and minerals are key nutrients that are essential in the regular functioning of the human body. They are needed in small amounts and are usually acquired from vegetables and fruits (Dobson 12). When acquired properly, vitamins can competently play the role assigned to them and they can observe their duties, such as to keep the immune system running, contribute to the structural integrity of the body, and strengthen the sensory systems. Their deficiency in the body leads to problems in these systems, which may result in lethal risks for health. For example, “lack of vitamin D damages immunity to cause cancers, diabetes and infections” (Mirkin).

Vitamins can be classified as water soluble and fat soluble. Generally, the vitamins that are soluble in water are absorbed by the body in the quantities that are needed. The excess is excreted in urine. Thus, it appears that abundant use of pills containing such vitamins produces nothing but expensive urine. As for the vitamins that are soluble in fat, their excess is stored in fat tissues and is retrieved in case of need (“Vitamins and Minerals”). This is an undesired effect, because it tires the body, which is otherwise a perfectly adjusted system.

Motivation for vitamin supplements

In the last century, a lot of research has been done to establish the amounts of vitamins and minerals needed for regular functioning of the body. With this knowledge, there is a growing concern among the public about their nutrition in recent years. People often think that the foods they are consuming do not contain necessary or sufficient amounts of vitamins and minerals.

It is not difficult to see that this concern has been formed by the artificial agendas of certain specialists. These specialists use methods that evoke feelings of anxiety, fear, desire, and the wish for perfection. The visual media and the press have certainly been the main and most effective means of propagating this agenda. Based on consultation with the specialists, vitamin-producing companies make promises to the consumers through advertisements that highlight how good vitamins are for children, adolescents and the elderly. They promise, for example, that if certain vitamins are used, people will feel better, improve their memory or remove aging effects. They claim that some of the vitamins they are selling have a healing or preventive power against diseases about which people are most concerned or fearful. Cancer, cardiovascular problems and obesity are among the most commonly emphasized such diseases. In the same way, abusing people’s desire for a long life, they claim that some vitamins increase life expectancy. For children, their inherent desire to be like adults is abused and they are promised that if they use certain vitamins they will be strong. These claims are reinforced with video clips in order to make them appear more realistic, and they are further supported by frequent repetition in the visual media.

Food supplements designed to meet the needs of the body are also put in “costumes” to allure the consumers. Product packaging uses big bullet points to present information about their extra vitamin content. In parallel to this, in the stores where these vitamins are sold, life-size pictures of famous or well-built people are displayed.

The Vitamin Market

As a result of all these efforts, many people think that a healthy life is not possible without vitamin pills. According to a survey by the USDA (United States Department of Agriculture) two decades ago, around fifty percent of the population from 19–50 takes a multivitamin pill every day. That survey showed a significant increase compared to another one performed five years earlier (Driskell). According to this trend, the vitamin supplement consumption is likely to have achieved much higher levels in our time.

Thus, an enormous market has formed for vitamin and mineral pills. It is estimated that this market amounts to an annual sales value between three and five billion dollars (Anderson, Wilken). With a drive to get a share of the sales, all supermarket chains have opened sections for vitamin pills and sell various kinds of vitamin supplements. Not only is the vitamin industry doing all these promotions for its own benefit, but media companies are also thriving on such advertisements. Unfortunately, this is sometimes a major reason for the media not to go after certain issues.

What is wrong?

Research shows that people get the correct quantity of vitamins and minerals if they consume a variety of natural foods and drinks. In countries with a high per capita income, some foods and drinks are even enriched with extra vitamins to ensure that vitamins are taken in sufficient amounts. As a result, for a person who is on a normal diet, a multivitamin pill is very likely to be excessive. With regard to these pills, nobody knows what amount is good for which person under what conditions. It is strange that the quantity of fruits and vegetables corresponding to the same amount of vitamin contained in a multivitamin pill is not revealed. Perhaps if this were calculated, the insanity of vitamin supplements would become evident. Do we really need to eat as many vegetables as a cow or a horse?

At the top of the direct vitamin intake options are vitamin pills. The majority of vitamin pills are marketed as a multivitamin-combinations of different vitamins and minerals. Supplying various combinations of vitamins in a single pill seems like a good idea at first. However, when we look at the production of vitamin pills, we see that the production process has not been standardized. Each company makes its own vitamin combinations and markets them. On top of their content, the daily consumption of synthetic vitamin pills is also variable based on the demands of the individual consumer. Although some companies include a recommendation on the packaging, in the end they say that their product can be consumed to the extent it is needed. For many vitamin pills, information about their solubility in water or fat is not present either. However, such pieces of information are of vital importance for their healthy consumption.

In recent times, with their wider use, these synthetic pills have been held responsible for health problems, contradicting expectations of health improvement, but so far they have not gained a bad reputation related to side-effect or harm. The prevailing view is that the more vitamins one takes, the better one’s health. This view might be true for natural vitamins; however, it is not so for synthetic vitamins. Generally, side-effects are associated with high dosages and undiluted intake, neither of which occurs in their natural counterparts.

Multivitamin pills are usually combined with minerals. Thus, while taking vitamin supplements, minerals are also taken, regardless of the need for them. However, similar to vitamins, minerals also are bad for human health when taken in excess. They interact with and counteract each other, and hence they disturb the body’s equilibrium.

In a study by Goran Bjelakovic and Christian Gluud, which was published in the journal of National Cancer Institute, it is stated that “Our diets typically contain safe levels of vitamins, but high-level antioxidant supplements could potentially upset an important physiological balance” (Bjelakovic, Gluud 742). They claim that antioxidant vitamins (A, C, E) do not provide any benefit when consumed in pills: if they are used as such, each results in certain forms of harm according to their function in the body. Bjelakovic and Gluud proved that such vitamin pills neither prevent nor cure cancer, that they do not protect the cardiovascular system, do not increase life expectancy nor alleviate the effects of aging. On the contrary, they showed that these antioxidant vitamin pills increase the risk of the diseases mentioned above. For example, a male person who is taking one multivitamin pill per day is doubling his risk for developing prostate cancer.

Some supplements can also have drug-like effects which present risks for people with certain medical conditions. A vitamin supplement brand was found to have potentially dangerous interactions with a number of prescription drugs (“‘Miracle’ Health Claims”).

At the very least, such side-effect-related cases call for a sound understanding of how these substances interact with the body. Can the human body convert synthetic vitamins to a usable form? Can they be stored and used later in case of vitamin deficiency? Are vitamin supplements, especially synthetic pills, as effective as natural vitamin sources, such as fruits and vegetables? What are the side effects associated with synthetic vitamins? What happens to vitamins in the case of overdose? Unless there are factual answers to these questions, vitamin pills should not be considered safe to use, and people should not use vitamin and mineral pills without consulting a doctor (“Vitamins and Minerals”).

Watch out for your health!

Here is the dilemma now: on the one hand, vitamin manufacturers are struggling to show the benefits of vitamin pills so that they make more profit; on the other hand, there is other research proving the detrimental effects of vitamin pills. At this point, it is nice to see a parallel dilemma in the fast-food market. If you go to a fast-food restaurant, their “nutrition facts” sheets show how healthy their food is. They even compare their food with other companies’ food in order to highlight their quality. However, there is a general consensus about unhealthiness of fast-food as demonstrated in the movie “Supersize Me”. Be it the food industry or the dietary supplement industry, there are claims from the producers which contradict the facts observed in real life. What to believe and who to trust are not clear.

One recourse in this ambivalence is the federal regulations or official advice from government scientists. In theory, health-care standards are established by either legislators or health organizations. However, in practice, there is a lack of institutes which can undertake the control of production of synthetic vitamin pills. In the US, for example, according to the Federal Trade Commission’s report, “Dietary supplements are not required to undergo government testing or review before they are marketed” (“Miracle’ Health Claims”). So, existing US health organizations, such as the FDA (Food and Drug Administration), do not accept any responsibility.

The main reason for not checking the harm associated with vitamin pills is that their side effects emerge in the long run. Consumers do not have the means to prove their cases, and consumer associations do not have enough financial power to take legal action against the producer companies. Therefore, there is no legal or practical base to pursue allegations related to the use of vitamin supplements. Given all this, using vitamin and mineral supplements is not very different from gambling with our health.

The above discussion provides enough information to evoke questions in the mind of the reader. Protecting people from the harm caused by vitamin pills is not possible through financial or judicial means at present, but it may be possible in the future through their long term results appearing as people with severe health problems. Let us hope that the people who have control over these issues will act in consideration of everybody’s health as an invaluable trust granted to them.

Alper Bursali is a senior student at West Virginia University, Biology Department.

References

• Bjelakovic, Goran, and Christian Gluud. “Surviving Antioxidant Supplements.” Editorial. Journal of the National Cancer Institute, 16 May 2007:742-743.
• Dobson, Roger. “The A to Z of vitamins;” Independent Extra, 6 Mar. 2007. 25 June. 2007 http://web.lexis-nexis.com.www.libproxy.wvu.edu/universe/printdoc
• Driskell, Judy A. Vitamin-Mineral Supplements and Their Usage by Adults. 28 June 2007 http://www.healthgoods.com/Education/Nutrition_Information/
• Nutritional_Supplements/supplements_usage_adults.htm
• Familydoctor.org 2004. Vitamins and Minerals: What You Should Know. Sept. 2004 http://familydoctor.org/online/famdocen/
• home/otc-center/otc-medicines/863.html
• Fogle, C., J. Anderson and K. Wilken. Mar. 2002. 29 June 2007 http://www.ext.colostate.edu/PUBS/foodnut/09338.pdf.
• ‘Miracle’ Health Claims: Add a Dose of Skepticism. September 2001. Federal Trade Commission. 20 June 2007 http://www.ftc.gov/bcp/conline/pubs/health/frdheal.shtm
• Mirkin, Gabe. Lack of Vitamin D causes Cancer. 5 Mar. 2007. 27 June 2007 http://www.drmirkin.com/nutrition/1337.html
• Sardi, Bill. Government/Scientific/Pharmaceutical/News Media Grip Over Dietary Supplements. 23 Jan. 2006. 27 June 2007 http://www.policestateplanning.com/dietary_supplements.htm

Radar, a contraction of the words radio detection and ranging, is an electronic device for detecting and locating objects. It operates by transmitting a particular waveform pattern and detects the nature of the echo (return) signal.1 Radar is used to extend the capability of the man’s senses, especially that of vision. We can think of radar as being a substitute for the eye, although it can do so much more: it can see objects through such impervious conditions as darkness, haze, fog, rain, and snow, for its wavelengths are much longer than those of visible or infrared light. The human eye works as a passive device, since the object is illuminated by sunlight or other light sources. However, radar produces its own illumination via electromagnetic waves, which means that it is an active device. 

APPLICATIONS OF RADAR AND RADAR IMAGING

Radar is used in civilian applications as air-traffic-control radar to guide aircraft to a safe landing, and in commercial aircraft as radar altimeters to determine height and weather avoidance, as well as wind-shear radars to navigate in severe weather conditions.

The military uses radar for surveillance and weapons control. Examples of such radars are DEW (Distant Early Warning) and AEW (Airborne Early Warning), which detect aircraft, long-range search radars, and guided missile radars.2

Research scientists use radar as a measurement tool. Radars have been placed on satellites, space modules, and shuttles to explore meteors, planets, and other objects in the solar system.

In the case of an imaging radar, the radar travels along an airplane’s or a space shuttle’s flight path. The area underneath is illuminated by the radar, and the radar architecture builds the image as it moves on the top of its footprint (Fig.1). The radar image’s finer resolution is achieved by using a very long antenna array to focus transmitted and received energy into a sharp beam.2 The beam’s sharpness defines the resolution. Similarly, such optical systems as telescopes require large apertures (mirrors or lenses that are analogous to the radar antenna) to obtain fine imaging resolution. Synthetic Aperture Radar (SAR) is a common and very popular technique in radar imaging that achieves a very fine resolution.3 In the following sections, we introduce and explain different types of SAR imaging techniques.

SYNTHETIC APERTURE RADAR (SAR)

SAR refers to a technique that synthesizes a very long antenna by combining echoes received by the radar when it travels.4.5 Typically, SAR is used to produce a two-dimensional (2-D) image. One dimension in the image is called range (or along track), and is a measure of the “line-of-sight” distance from the radar to the target (Fig.l). Range is determined by precisely measuring the time from a pulse’s transmission to receiving the echo from target. The range resolution is determined by the transmitted pulse’s width (i.e., narrow pulses yield fine range resolution).

The other dimension is called azimuth (or cross track), and is perpendicular to range. Usually, the length of the radar antenna determines azimuth resolution. However, a good azimuth resolution requires a radar antenna that is not practically carried by an airborne platform, for imaging radars are much lower in frequency (1 to 10 GHz) than optical systems (4,000 to 8,000 GHz). The length of the required antenna could be around several hundred meters, which obviously cannot be carried by an air vehicle.

However, SAR differs from other radars in that it collects data along the flight path when it travels, instead of using a large antenna. Therefore, a very small antenna is adequate for the job. After collecting the data, it processes this aperture data as if it came from a physically long antenna. The distance the aircraft flies in synthesizing the antenna is known as the synthetic aperture. A narrow synthetic beamwidth results from the relatively long synthetic aperture, which yields finer resolution than what is possible from a smaller physical antenna.

SARs are not as simple as described above. Transmitting short pulses to provide range resolution is generally not practical. Typically, longer pulses with wide-bandwidth modulation are transmitted, which complicates range processing but decreases peak power requirements on the transmitter. For even moderate azimuth resolutions, a target’s range to each location on the synthetic aperture changes along the synthetic aperture. The energy reflected from the target must be “mathematically focused” to compensate for the range dependence across the aperture prior to image formation. Additionally, for fine-resolution systems, range and azimuth processing is coupled (dependent on each other), which greatly increases computational processing. The trick in SAR processing is to correctly match the variation in frequency due to motion (moving target or moving radar) for each point in the image.

An example of SAR imaging is shown in Fig. 2. The colors in the image reflect the received signal intensity. The strongest signal level is red, whereas the weakest is black. The figure is a SAR image of San Francisco, California, obtained by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture (SIR-C/X-SAR) imaging radar when it flew aboard the space shuttle Endeavour on October 3, 1994. The size of the image is about 26 miles by 36 miles. The center of the area is 37.83 degrees north latitude, 122.38 degrees east longitude.

This particular SAR image is a good illustration of how SAR distinguishes urban areas from nearby relatively less populated areas. Such densely populated regions as downtown San Francisco (center) and the city of Oakland (at the right across the San Francisco Bay) show up as red images due to the alignment of streets and buildings vis A vis the incoming radar beam. The bridges in the area are easily detected by the imaging radar, including the Golden Gate Bridge (left center) at the opening of San Francisco Bay, the Bay Bridge (right center), and the San Mateo Bridge (bottom center). All dark regions on the image represent smooth water. Radar also easily detects the major faults in the area: those bounding the San Francisco-Oakland urban areas and the San Andreas Fault (at the lower left), As seen from the image, faults are shown as dark straight lines in the SAR image.

INCERSE SAR (ISAR)

While SAR images a region of the Earth from an airplane or an air shuttle, Inverse SAR (ISAR) images a flying object, such as airplane or an asteroid, from land-based radar. ISAR is very popular, and also very critical in military applications.6 It is commonly used for identification purposes. In a possible war scenario where there are too many aircraft in the sky, it is almost impossible to guess which one is friendly or hostile. In that case, ISAR imaging technique is used to identify the approaching aircraft and classify it from a collection of possible targets.

In theory, ISAR is an imaging technique that maps the locations of dominant scattering points of a target based on the multi-frequency, multi-aspect, backscattered data.7 In this data, the signal’s amplitude reflects the magnitude information of the scattering points on the target, while the backscattered signal’s phase is related to the location information of the scattering point off the target. After collecting this 2-D raw data, several signal-processing tools extract from this data the amplitude and location information of the scattering centers. Then, a 2-D image of the target is constructed by using a convenient image processing technique.

An example of ISAR imagery is shown in Fig. 3. The model of the test airplane (C-29 model) is shown at the lower portion, while a 2-D ISAR image of the airplane is constructed at the upper portion of Fig.3. The measurement is taken at the center frequency of 10 GHz, where the frequency bandwidth is 16 GHz. The data is collected from 0.10 steps to cover the entire 3600 azimuth. At the end, a 2048 by 2048 2-D grid is constructed by using the ISAR algorithm. By comparing both, it is seen that ISAR imaging provides accurate target information. By looking at this image, it is very easy to identify and classify the aircraft.

ISAR is an active operation of the radar at the target’s far field. Both receiving and transmitting antennas must be far away from the target. Recently, new ISAR imaging techniques that allow passive radar operation have been discovered. Antenna SAR (ASAR) and Antenna Coupling (ACSAR) imaging techniques use direct radiation from an antenna mounted on the near field of an airplane or a ship to image the dominant radiation points off these platforms. In these cases, the radar functions only as a receiver, for the target’s own antenna provides illumination to the target. These techniques are mainly used to determine the dominant radiation points off the target to explore ways to cancel or mitigate undesired extra radiation from the target’s platform.

The development of fast computers during the 1980s allowed researchers to apply intensive computational electromagnetic (CEM) tools that ultimately led them to develop new SAR/ISAR algorithms. One of the most appreciated and widely used tool is Interferometric Synthetic Aperture Radar (INSAR) imaging, which allows the extraction of height information that can be used to render 3-D topographic views of a SAR scene.

INTERFEROMETRIC SAR (INSAR)

Radar interferometry involves coherently combining radar measurements made by two or more radar antennas displaced by a relatively small distance.8 Depending on the relative geometry of the two antennas, the combined measurements can be turned into measurements of surface topography, topographic change, or displacement over time. Mapping precision of around 2m in three dimensions over a wide area is now possible from airborne interferometric radars.

Here is how an INSAR works: A radar system launches electromagnetic energy to scan the ground terrain to be imaged. Two radar antennas collect the backscattered wave to obtain two different snapshots of SAR image. To avoid phase ambiguity, these antennas must be close enough to each other. Since the waves travel different distances from a particular scatterer to each antenna, the resultant phases of each SAR image is different. In the next step, an image called interferogram is formed by multiplying one SAR image by the complex conjugate of the other SAR image. The phase of the interferogram represents the differences in range to the scattering centers of each pixel in the image. These differences are caused by the terrain’s topography. Then, a signal-processing algorithm converts this phase information to extract the terrain’s topographic features. Finally, a 3-D INSAR image of the region is formed by combining the SAR images with the height information.

An example of INSAR imaging is illustrated in Fig.4, which depicts the Long Valley of east central California. The images were taken by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour during its two flights in April and October 1994. The four images show the steps necessary to produce 3-D data from radar interferometry. The image covers an area of 21 by 37 miles. The radar illumination is from the top of the image. The bright areas are hilly regions of big rocks and pine forest; the darker areas are the relatively smooth, sparsely vegetated valley floors. The curving ridge running across the image’s center from top to bottom is the northeast rim of the Long Valley caldera, a remnant crater from a massive volcanic eruption roughly 750,000 years ago.

The image in the upper right is an interferogram of the same region, constructed by combining data from the April and October flights. The different phases are shown as different color levels. These variations are caused by elevation differences in the area. The same color levels indicate that those regions have same altitudes. The image in the lower left shows a topographic map derived from the interferometric data. The black bold contour lines represent levels of elevation. In this particular image, elevation levels are spaced at 250-meter intervals. The last image is a 3-D view of the northeast rim of the caldera, looking toward the northwest. As can be seen from the image, it is possible to extract such geologic structural and landform features as elevation, vegetation, and soil type with the help of INSAR processing.

Another example of INSAR imaging is shown in Fig. 5, which depicts the Washington, DC, Mall area. A similar approach is used to form this 3-D image. The region starts from the Capitol building (top) to the Lincoln Memorial and the Arlington Memorial Bridge (toward the right bottom). The Washington Monument is very easy to observe at the center of the image. The bright areas (from white to yellow) represent higher elevation places; darker colors (from green to dark blue) represent the areas of lower elevation. The Potomac river (right bottom of the image) and the reflecting pool (from the Lincoln Memorial toward the Washington Monument) are all in dark blue because of the water and the lowest elevations. We can also clearly distinguish Constitution Avenue running from bottom to top. The green regions are intermediate elevation consisting mostly of vegetation. As seen from the image, the highest elevation is the top of the Washington Monument, the Library of Congress building, and the Capitol building.

CONCLUSION

In this paper, we presented a survey study of radar basics and radar imagery. It is obvious that radar has been a very important and useful tool throughout the 20th century, both in the military and industry. With developments in the computer era and new imaging algorithms, it looks like it will be a very critical tool in the 21st century as well. It is now possible to simulate very complex models and targets in a reasonable computation time in radar frequencies thanks to new developments in computational electromagnetics methods (CEM). Examples of those are Xpatch9 (a high frequency code that can predict the scattering from large, complex bodies) and FISC10 (a fast simulator of electromagnetic bodies at high frequencies). While computers continue to grow faster and faster, new electromagnetic simulators are also getting faster and more efficient. As a result, more compact, fancier, faster, and more accurate radar-imaging techniques are being developed.

REFERENCES

1. Morris, G. V. and Harkness, L. (1996) ‘Airborne Pulsed Doppler Radar’, Artech House.
2. Mensa, D. L. (1981) ‘High Resolution Radar Imaging’, pp. 185-189, Artech House.
3. Wehner, D. R. (1994) ‘High-Resolution Radar’. Artech House.
4. Carrara, W. C., Goodman, R. S. and Majewski, R. M. (1995) ‘Spotlight Synthetic Aperture Radar: Signal Processing Algorithms’, Artech House.
5. Franceschetti, G. and Lanari,. (1999) ‘Synthetic Aperture Radar Processing’, C. R. C. Press LLC.
6. Baltes, H. P. (1980) ‘Inverse Scatteiing Problems in Optics’, Springer-Verlag.
7. Chu, T. H. and Lin, D. B. (1991) ‘Microwave diversity imaging of perfectly conducting objects in the near-field region’, IEEE Trans. Antennas Propagat., vol. 39, pp. 480-487.
8. Askne, J., et al. (1997) ‘C-band repeat-pass inter ferometric SAR observations of forest, IEEE Trans. on Geoscience and Remote Sensing, vol.35, pp. 25-35.
9. Lee, S. W. (1992) ‘Test cases for XPATCH’, Electromagn. Lab. Tech. Rept., ARTI-92-4, Univ. of Illinois.
10. Ctr. Computat. Electromagn. (1997) ‘User’s Manual for FISC (Fast Illinois Solver Code)’, Univ. Illinois, Urbana-Champaign, and DEMACO. Inc.