<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
	>

<channel>
	<title>fiber &#8211; Fountain Magazine</title>
	<atom:link href="https://fountainmagazine.com/tag/fiber/feed/" rel="self" type="application/rss+xml" />
	<link>https://fountainmagazine.com</link>
	<description></description>
	<lastBuildDate>Tue, 01 Jul 2014 00:00:00 +0000</lastBuildDate>
	<language>en-US</language>
	<sy:updatePeriod>
	hourly	</sy:updatePeriod>
	<sy:updateFrequency>
	1	</sy:updateFrequency>
	<generator>https://wordpress.org/?v=7.1</generator>
	<item>
		<title>Major Task for a Tiny Fiber</title>
		<link>https://fountainmagazine.com/all-issues/2014/issue-100-july-august-2014/major-task-for-a-tiny-fiber-july-2014/</link>
		
		<dc:creator><![CDATA[Louima Cunningham]]></dc:creator>
		<pubDate>Tue, 01 Jul 2014 00:00:00 +0000</pubDate>
				<category><![CDATA[Issue 100 (July - August 2014)]]></category>
		<category><![CDATA[aorta]]></category>
		<category><![CDATA[blood]]></category>
		<category><![CDATA[body]]></category>
		<category><![CDATA[chromosome]]></category>
		<category><![CDATA[connective]]></category>
		<category><![CDATA[disease]]></category>
		<category><![CDATA[elastic]]></category>
		<category><![CDATA[Elastin]]></category>
		<category><![CDATA[Emilin]]></category>
		<category><![CDATA[eye]]></category>
		<category><![CDATA[FBN]]></category>
		<category><![CDATA[fiber]]></category>
		<category><![CDATA[fibers]]></category>
		<category><![CDATA[fibrillin]]></category>
		<category><![CDATA[Fibulin]]></category>
		<category><![CDATA[genes]]></category>
		<category><![CDATA[heart]]></category>
		<category><![CDATA[Nesprin]]></category>
		<category><![CDATA[number]]></category>
		<category><![CDATA[occur]]></category>
		<category><![CDATA[organs]]></category>
		<category><![CDATA[protein]]></category>
		<category><![CDATA[relax]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[skin]]></category>
		<category><![CDATA[thousand]]></category>
		<category><![CDATA[tissue]]></category>
		<guid isPermaLink="false">http://107.21.79.195/all-issues/2014/issue-100-july-august-2014/major-task-for-a-tiny-fiber-july-2014/</guid>

					<description><![CDATA[My name is fibrillin, also known as FBN. I am a protein whose synthesis starts while you are still in your mother&#8217;s womb. I was discovered in 1986. I provide services to you in my mature form, once I go through a series of long and complicated processes. During my services, I work together with [&#8230;]]]></description>
										<content:encoded><![CDATA[<p>My name is fibrillin, also known as FBN. I am a protein whose synthesis starts while you are still in your mother&#8217;s womb. I was discovered in 1986. I provide services to you in my mature form, once I go through a series of long and complicated processes. During my services, I work together with many sister molecules, such as nesprin, fibulin, emilin and elastin.</p>
<h3>Where am I?</h3>
<p>There are 46 chromosomes in your body, carrying 20-25 thousand genes. Chromosomes and the genes they contain shape the genetic memory of a human being. Genes can contain hundreds of features, and these are revealed over time. For instance, you do not have any teeth when you are a newborn, but the time when you will get your teeth is encoded into your genetic memory. Once genes receive the action command, teeth start to emerge.</p>
<p>There are hundreds of genes located on chromosomes, all the way from the chromosome number 1 and 2, to chromosome number 46. For example, there are around three thousand genes found on chromosome number 1. The Y chromosome, in charge of male development, only contains 125 genes. A distinct address (locus) for each gene on the chromosomes is recorded. If you ask about the address of the fibrillin gene that synthesizes me, it is 15q 21.1, i.e., 15th Avenue, Long arm street, 21st pl, Number 1.</p>
<p>In other words my residing address is the 1st subband of the 1st band of the 2nd region located at the long arm of chromosome number 15. We are three siblings, known as fibrillin1, fibrillin2 and fibrillin3.</p>
<p>We stretch and relax like an arch. We can expand and tighten like an inflated balloon and then return to our previous state. If by an error, we happen to fail to restore ourselves after inflation, the tissue&#8217;s architecture gets deformed and expanded fibers cannot regain their original shape anymore. When observed in veins, this situation is called an aneurysm. The frequency of this disease is approximately one in ten thousand, which is also called ballooning. That said, my flexing is necessary. Veins flex so that the blood pumping through them doesn&#8217;t cause any turbulence, as it would otherwise be during a vacuum occurring inside metal water pipes. Flexible sportsmen who do acrobatic moves do not compare with me. I can bend, curve, flex, relax and constrict, inflate, deflate and transform like elastic, from one shape to another, for your health and overall convenience &#8211; all because of the wondrous features granted to my nature.</p>
<h3>What kind of a fiber am I?</h3>
<p>I provide structural support for the fabrication of elastic fibers in the connective tissue as a protein synthesized according to the code of the fibrillin gene. In case of my failure or absence, weaknesses occur, especially in the connective tissues of organs that are rich in elastic fibers, such as the aorta, lungs, and eye balls. The iris (the colored part of the eye), pupil, and eye lens display changes in accordance with levels of light or distance of objects observed. These changes are controlled perfectly according to my work, and humans often don&#8217;t even notice this. We also help the eye lens constrict and relax. It can be understood that we are such a great blessing granted for your service. Of course, if we tried to count all the blessings we&#8217;ve been given, and never even consider, it would be impossible!</p>
<p>My weight is 350 kilo daltons. A Dalton is an atomic mass unit approximately equal to one hydrogen atoms&#8217; mass, which is 1.66&#215;10-24. I consist of 2.871 amino acids. I am formed by the sequential arrangement of 20 amino acids that exist in your body as the smallest unit of proteins. We bind each other to become 10-12 nanometers wide microfibers as the result of a process called polymerization that brings loops of a protein chain together. These microfibers are brought together with the elastin protein that provides elasticity in our body. The system that we form with elastic fibrils constantly serves the body&#8217;s blood vessels, primarily the vessels located in your eyes, heart, and many of your tissues, such as your skin and nerves.</p>
<p>What do I do? We fulfill commands that are requested from us in many tissues and organs, without any flaws. Scientists call us the wonderful building blocks of the body&#8217;s architecture. We can extend twice as much of our length. We are always on task: while you are breathing, when your heart is pumping blood and your stomach is digesting food, or the moment you are gazing at nature with your eyes. We are given the duty to prevent many organs from tearing, including the heart, lungs, stomach, and blood vessels. One of the places I work most frequently is the aorta, the body&#8217;s major artery. Your heart beats approximately a hundred thousand times a day. A high level of pressure develops in the arteries during the pumping process. You would suffer greatly without the help of our elastic fibers. Blood vessels would rupture, ending your life. This high pressure is tolerated only through the expansion of the vessel&#8217;s diameter without any decrease in length of the artery. This diameter regulation is designed so wondrously that blood flow remains the same; no shaking or waves are observed. This diameter control happens via the fibrillin protein located inside the vessel.</p>
<p>I also play a role in the vitality and tension of your skin. Skin is essentially a dense fibrous connective tissue composed of a protein called collagen. I am also one of the main elements of this connective tissue. As you age, this layer starts to dry and has lesser fibrous proteins; therefore, as fibers decrease, so does my tension, and I start to wrinkle. Elderly people do not like getting wrinkly, but this is your fate. Whatever you do, I will also age and die.</p>
<p>I cannot go without pressing this important issue: Staying under the sun for a long time degrades me. If done properly, sun light is useful for skin. But solar radiation damages the live tissues and organs. This radiation is an effective factor both in degradation of protein structures, and the formation of varicose veins and skin damage. It is reported in various sources that exposure to sun rays leads to alterations in the genetic material of skin. Ultraviolet rays speed up the degradation of skin. In medical language, this is called oxidation via free radicals. Please do not burn us and yourself while sunbathing. Even if you do not care for yourselves, you should still be considerate of us. If you say that sunbathing both helps, with vitamin D synthesis and reducing the risk of osteoporosis, I would like to remind you that for the vitamin D synthesis of skin, it is sufficient to expose your hands, feet and face to the sun.</p>
<h3>How is life without me?</h3>
<p>Though we were wisely designed, sometimes, you are tested by certain diseases in which we are not present. Absence, as they say, makes the heart grow fonder!</p>
<p>Life without me is unbearable. I could give a couple of examples, should you like. If I was not created, your skin would not be flexible. You wouldn&#8217;t be able to control your eye lenses. Your aorta would not be flexible and your heart, which beats thousands of times a day, would be torn under the high pressure in a short amount of time. Major problems would occur with the development of your stomach, lungs, and other organs.</p>
<p>I also have a significant job keeping TGF-Beta (which helps cells grow) function under control. To give you an idea of how important this is, imagine your communication system turned upside down. Now imagine how complicated are the communication systems connecting billions of people around the world, how a mess it would be when they are out of service. These are nothing when compared to the human body. There are 100 trillion cells in the human body, communicating with each other instantaneously. A cellular community that is fifteen thousand times more crowded than the earth&#8217;s population communicates via small molecules, like us. Cellular proliferation and tissue differentiation would fail if cells failed to communicate. The full spoon of food in your hand would not end in your mouth but maybe in your ear or your eyes.</p>
<p>If a mutation happens with the Fibrillin-1 gene, Marfan syndrome can occur. This disease, which was defined in the 1800s, is named after its discoverer. The frequency of this disease is one in five thousand. One of the major lethal consequences of Marfan syndrome is an aorta tear. This is in addition to many problems with the eyes, skeleton, and cardio-vascular systems. Many of the patients die in their 30s or 40s because of the flaws in the cardio-vascular system. Of course, death may occur at any age because of an aorta rupture. 14% of the patients with Marfan syndrome display chronic obstructive pulmonary disease (COPD), which is associated with breathing problems, because the integrity of lung tissue is compromised. Another disease I help prevent is called Ektopia lentis, in which the eye lens is displaced from its original position. Normally, I help eye functioning. When my fibers relax or constrict, depending on light, I help the eye to relax, enabling both near and far sightedness. With Ektopia lentis, anomalies on the front vestibule of the eye, a high degree of myopia, and retina damage occur.</p>
<p>If overproduced, I can cause another problem with the eye, called exfoliation syndrome. This is when fibrous connective tissue, like me, accumulates in the eye &#8211; it&#8217;s commonly called glaucoma, or ocular hypertension. In some people, as they age, a fibrous material like hair dandruff collects on the eye lens. This material, dislocated by movements of the iris, blocks the drainage channels that discharge the intraocular fluid. Eye pressure increases as the result of failed drainage. As you see, I am not a problem when I am synthesized normally, but can be trouble if over produced! My final request from you!</p>
<p>You have seen our amazing works and complicated functions. Therefore, please remember me and my friends. Please do not ignore our efforts and activities. Be grateful for the blessings provided through us, even if you can&#8217;t see them. And take care of us, please &#8211; don&#8217;t get carried away with too much tanning!</p>
]]></content:encoded>
					
		
		
			</item>
		<item>
		<title>Your sleep shapes your hair</title>
		<link>https://fountainmagazine.com/all-issues/2011/issue-79-january-february-2011/your-sleep-shapes-your-hair/</link>
		
		<dc:creator><![CDATA[The Fountain]]></dc:creator>
		<pubDate>Sat, 01 Jan 2011 00:00:00 +0000</pubDate>
				<category><![CDATA[Issue 79 (January - February 2011)]]></category>
		<category><![CDATA[Bacterial guests]]></category>
		<category><![CDATA[body]]></category>
		<category><![CDATA[children]]></category>
		<category><![CDATA[circadian]]></category>
		<category><![CDATA[diet]]></category>
		<category><![CDATA[expression]]></category>
		<category><![CDATA[fiber]]></category>
		<category><![CDATA[food]]></category>
		<category><![CDATA[genes]]></category>
		<category><![CDATA[gut]]></category>
		<category><![CDATA[hair]]></category>
		<category><![CDATA[Malagasy spiders]]></category>
		<category><![CDATA[rhythm]]></category>
		<category><![CDATA[rich]]></category>
		<category><![CDATA[Science Square]]></category>
		<category><![CDATA[sleep]]></category>
		<category><![CDATA[spiders]]></category>
		<category><![CDATA[study]]></category>
		<guid isPermaLink="false">http://107.21.79.195/all-issues/2011/issue-79-january-february-2011/your-sleep-shapes-your-hair/</guid>

					<description><![CDATA[1- Your sleep shapes your hair Original Article: Akashi M. et al., PNAS 107, 15643 (2010). Feeling sleepy during the day after a long flight? Internal body clock genes are to blame. Circadian (Latin: “around” “the day”) rhythm genes take part in a time dependent cycling of an organism to carry out daily physiological processes. [&#8230;]]]></description>
										<content:encoded><![CDATA[<h3><b>1- Your sleep shapes your hair</b></h3>
<p><em>Original Article: Akashi M. et al., PNAS 107, 15643 (2010).</em></p>
<p>Feeling sleepy during the day after a long flight? Internal body clock genes are to blame. Circadian (Latin: “around” “the day”) rhythm genes take part in a time dependent cycling of an organism to carry out daily physiological processes. These signals include very basic needs such as feeling sleepy at nighttime and waking up during the day and repeats about every 24 hours. Malfunctioning circadian rhythm genes are implicated in several sleep disorders. According to a recent study done by Makoto Akashi and his colleagues at Yamaguchi University in Japan, hair follicle cells were found to closely follow the gene expression pattern of the internal circadian rhythm of the human body. Gene expression patterns can be extracted from hair follicles from pulled hair. Studying the circadian rhythm genes and expression profiles has been quite an inconvenience for researchers up until now. This study provides a new alternative method for tapping into this machinery. Don’t be surprised if you are asked for a couple of hairs pulled from your scalp if you go to a doctor complaining about your sleep disorder in the future. This method could have implications in the field of diagnostic medicine as a less invasive method for diagnosing problems since it allows us to conveniently gain access to the gene expression profiles of a person. We are not at a stage where we can control our sleep cycle at our convenience, but this is a step towards facilitating our understanding of this mechanism.</p>
<h3><b>2- Western diet disturbs our bacterial guests</b></h3>
<p><em>Original Article: De Filippo C. et al., PNAS 107, 14691 (2010).</em></p>
<p>Did you know that there are 100 trillions of microbes living happily ever after in your gut? This is about 10 times as many cells as make up the whole human body. But, no need to panic, because the sole purpose of their presence is to serve us by aiding in our daily digestion, metabolism and improving our immune system overall. A recent study shows that our friendly inhabitants are drastically affected by the human diet. A research group at Meyer Children Hospital in Italy analyzed and compared the fecal microbiota of children from Europe to that of children from rural African village of Burkino Faso (BF). When they examined the diets of each group closely, they saw that the BF diet is rich in cereals, vegetables and legumes, whereas the European diet is usually rich in animal protein, sugar, starch, and fat. Thus, children from Africa typically have a high-fiber diet and the children from Europe have a low-fiber diet. Next, researchers characterized the gut microbiotas of each group from fecal samples. The results revealed that gut microbiota was drastically different between these groups. Interestingly, BF children had several types of bacteria that seem to produce substantial amounts of short chain fatty acids (SCFAs) as a result of fiber-rich diet. The high levels of SCFAs are known to result in high energy levels and an increased anti-inflammatory capacity. The fact that African populations have almost no non-infectious colonic diseases may be attributed to the enriched diversity of gut microbiota due to the high-fiber diet of African children. This study once again emphasizes the importance of a fiber rich diet and it becomes clear that the adoption of such a diet and refraining from fast food culture would be beneficial to all of us.</p>
<h3><b>3- Eat more, enjoy less </b></h3>
<p><em>Original Article: Stice E. et al., The Journal of Neuroscience 30, 13105 (2010).</em></p>
<p>Why do obese people tend to overeat? A new study suggests a vicious cycle stemming from an obese individual’s desire to compensate for reduced pleasure from food. Degree of pleasure derived from eating correlates with the amount of released dopamine, which is associated with food intake. The researchers studied 26 overweight and obese volunteers, who were subjected to fMRI brain scans to identify brain regions that became active as they sipped both sugary milkshakes and a flavorless liquid. Every participant was tested twice over a six month period. Participants who gained weight showed significantly less activation in response to the milkshake intake upon a six-month follow-up relative to their baseline scan and relative to participants who did not gain weight. According to these results intake of palatable food results in down regulation of D2 receptors, reduced D2 sensitivity, and decreased reward sensitivity, implying that overeating may contribute to reduced striatal responsivity. These results will likely be important in developing programs to prevent and treat obesity, and also help us understand why obesity typically shows a chronic course and is resistant to treatment. Here is another reason to eat less: to get more pleasure from the food we eat.</p>
<h3><b>4- Tough Malagasy spiders </b></h3>
<p><em>Original Article: Agnarsson I. et al., PLoS one 5, e11234 (2010).</em></p>
<p>There are 40,000 kinds of spiders. They have little bodies, but the webs that they knit with their long thin legs using the silk from their tiny bodies are examples of great talent. Among the 200,000 types of silk which spiders produce, each have different combinations of properties, such as stickiness, durability or thickness, etc. A recently discovered spider found in Madagascar has an even more amazing talent. This kind of spider with its 3–5 cm long body size can make a web that can cross a river 2.5 meters wide with the ends of the nets attached to trees on either bank of a riverside. These nets have been found to be the strongest biological material ever known. After careful measurement, it was discovered that these webs are 10 times stronger (350 MJ/m3) than Kevlar, which is the material used in bulletproof vest, and some threads become even more durable (520 MJ/m3), which means that this spider beats even the most talented scientists and engineers with its skinny small legs and tiny little brain by developing material which is more than ten times tougher. It is believed that these spiders need to have strong nets in order to bare the extreme weather conditions above the river and catch the bugs flying over the river. There are still investigations that have yet to be done in order to find out further properties of such webs. “Verily in these things there are signs for those who consider.”</p>
]]></content:encoded>
					
		
		
			</item>
		<item>
		<title>A Tale of Design and Love</title>
		<link>https://fountainmagazine.com/all-issues/2007/issue-59-july-september-2007/a-tale-of-design-and-love/</link>
		
		<dc:creator><![CDATA[Louima Cunningham]]></dc:creator>
		<pubDate>Sun, 01 Jul 2007 00:00:00 +0000</pubDate>
				<category><![CDATA[Issue 59 (July - September 2007)]]></category>
		<category><![CDATA[bar]]></category>
		<category><![CDATA[cage]]></category>
		<category><![CDATA[fiber]]></category>
		<category><![CDATA[fibers]]></category>
		<category><![CDATA[figure]]></category>
		<category><![CDATA[flower]]></category>
		<category><![CDATA[grid]]></category>
		<category><![CDATA[host]]></category>
		<category><![CDATA[index]]></category>
		<category><![CDATA[light]]></category>
		<category><![CDATA[optical]]></category>
		<category><![CDATA[refractive]]></category>
		<category><![CDATA[scale]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[sea]]></category>
		<category><![CDATA[shrimp]]></category>
		<category><![CDATA[silica]]></category>
		<category><![CDATA[spicules]]></category>
		<category><![CDATA[sponge]]></category>
		<category><![CDATA[structure]]></category>
		<category><![CDATA[venus]]></category>
		<guid isPermaLink="false">http://107.21.79.195/all-issues/2007/issue-59-july-september-2007/a-tale-of-design-and-love/</guid>

					<description><![CDATA[The value of the iron (or any other material) from which a work of art is made differs from the value of the art expressed in it. Sometimes they may have the same value, or the art’s worth may be far more than its material, or vice versa. An antique may fetch a million dollars, [&#8230;]]]></description>
										<content:encoded><![CDATA[<p><em>The value of the iron (or any other material) from which a work of art is made differs from the value of the art expressed in it. Sometimes they may have the same value, or the art’s worth may be far more than its material, or vice versa. An antique may fetch a million dollars, while its material is not even worth a few cents. If taken to the antiques market, it may be sold for its true value because of its art and the brilliant artist’s name. If taken to a blacksmith, it would be sold only for the value of its iron. (Nursi, The Words, Twenty-third Word, First Point)</em></p>
<p>Each creation is a work of art. All animals and plants, as well as every human being, are unique and priceless. And those who appreciate their value are like antique dealers as in the passage above. I recently had the chance to listen to such an “antique dealer,” Joanna Aizenberg of Bell Laboratories/Lucent Technologies, and witnessing the appreciation of the valuables she presented to us helped me better understand Said Nursi. Both the valuable object she was talking about and her appreciation of it were equally inspiring for me, and this is the reason why I have decided to share this story with you. Without any further ado, here is the story of a sponge species called the Venus’ Flower Basket and its “eternally” incarcerated residents: a pair of shrimp. Now, you must find what is hiding behind all this; after all, it is the eyes that look but the heart that perceives.</p>
<p>Venus’ Flower Baskets (Figure 1a) are vase-like sponges that grow upright on the sea floor of the Pacific Ocean, mostly around Japan. They have a very sophisticated mesh structure which caused medieval Europeans to assume they were glasswork made in China. In Japan they are called Kairou-Douketsu (together for eternity) and given as wedding gifts, since they generally house a pair of mated shrimp which are trapped in their cavity. As you have probably already understood, our story is about the engineering secrets of these sponges and their relationship with their guests.</p>
<h3>The design</h3>
<p>The skeleton of the Venus’ Flower Basket is made of silica, which is a very brittle material (remember the glass windows that you broke with your football when you were a kid; they were made with silica). How can these amazing creatures withstand the pressure and the currents present at the sea floor or the disturbance caused by two shrimp? The secret lies in the hierarchical construction of their cylindrical cage-like structure. As can be seen in Figure 1b, their skeleton is made up of beams that run perpendicular and parallel to the axis of the sponge, which forms a rectangular grid. This grid is further supported by beams that run diagonally in both directions. Finally, this whole structure is reinforced by ridges that spiral around. But these are just the macroscopic hierarchical levels of the construction. Now let’s start from the very first level of this hierarchy and try to understand how each level adds to the stability of the sponge.</p>
<p>The basic building block of the Venus’ Flower Baskets is a fiber composed of silica nano-spheres (Figures 1i and 2a) that grows around an organic filament (the black dots at the center of the circles in Figure 1f). Though this fiber is not very stress tolerant, due to the size of the spheres from which it is made, in the next level of hierarchy it is toughened by alternating organic and silica sheets that form a concentric lamellar (fine, alternating layers of different materials) fiber structure. The thickness of each layer in the fiber decreases from 1.5 (: 1/1000 mm) at the center to 0.2 towards the periphery (Figures 1f, 1g and 2b). Hence any crack that is initiated at the periphery is halted at the organic interlayers and while the thinner outer layers lessen the depth of crack propagation, the thicker inner layers enhance mechanical rigidity (in addition to their mechanical stability, these silica fibers are endowed with optical properties which are superior to man-made fibers, which will be discussed later on in the article).</p>
<p>Figure 1. Structural analysis of the mineralized skeletal system of Euplectella sp. (a) Photograph of the entire skeleton, showing cylindrical glass cage. Scale bar, 1 cm. (b) Fragment of the cage structure showing the square-grid lattice of vertical and horizontal struts with diagonal elements arranged in a chessboard manner. Orthogonal ridges on the cylinder surface are indicated by arrows. Scale bar, 5 mm. (c) Scanning electron micrograph (SEM) showing that each strut (enclosed by a bracket) is composed of bundled multiple spicules (the arrow indicates the long axis of the skeletal lattice). Scale bar, 100 mm. (d) SEM of a fractured and partially HF-etched (25) single beam revealing its ceramic fiber-composite structure. Scale bar, 20 mm. (e) SEM of the HF-etched (25) junction area showing that the lattice is cemented with laminated silica layers. Scale bar, 25 mm. (f) Contrast-enhanced SEM image of a cross section through one of the spicular struts, revealing that they are composed of a wide range of different-sized spicules surrounded by a laminated silica matrix. Scale bar, 10 mm. (g) SEM of a cross section through a typical spicule in a strut, showing its characteristic laminated architecture. Scale bar, 5 mm. (h) SEM of a fractured spicule, revealing an organic interlayer. Scale bar, 1 mm. (i) Bleaching of biosilica surface revealing its consolidated nanoparticulate nature (25). Scale bar, 500 nm. Figure and captions from ref. 2.</p>
<p>Fibers of different diameters reinforced this way are then bundled loosely in a silica matrix (Figure 1d and 1f). The different diameter of the fibers in the bundle and the weak lateral bonding between them are essential for increasing the strength of the bundle against crack propagation. At the next level of hierarchy, these bundles are used as building blocks of the cylindrical cage of the sponge, being arranged horizontally and vertically into a square grid. This grid in turn is reinforced by diagonal bundles that run in both directions along every second square lattice. The minimum number of pin-jointed struts (i.e. ones that are free to rotate at the joints) per node needed in order to form a rigid two-dimensional grid has been shown to be six; this is the number present in the skeleton of the Venus’ Flower Basket. In fact, if the diagonal bundles were to run along every square lattice, the number of struts per node would be 8, which would be redundant for the stability in the skeleton.</p>
<p>At the early stages of the growth of the Venus’ Flower Basket the struts are not connected at the nodes. However as the sponge gets older the struts are joined by a silica cement which itself also has a lamellar structure (Figure 1e). Hence, while the younger sponges are flexible, the older ones are stiff; this also has important implications for the symbiotic relation that the sponge has with its guests, the shrimp. (This issue will be discussed in detail when the lifecycle of the shrimp is examined.) While the resulting grid is stable in two dimensions, in three dimensions it may still suffer from exterior effects, such as ovalization. This problem however is solved at the next level of hierarchy by the helical ridges that surround the grid (Figure 1b). The absence of the ridges at the base of the skeleton of the sponge where the cage diameter is small, and their increased density further up the cage where the diameter is much greater is proposed as evidence supporting this argument. Finally, this whole cage structure must be anchored to the sea floor in a way that will withstand the bending stresses caused by the currents. This is managed through the use of the fibers that have been discussed earlier; they are used as connectors between the base of the sponge that is anchored to the sea floor and the vertical struts of the skeleton, resulting in a flexible connection that enables the cage to swing freely in the currents (Figure 1a).</p>
<p>As a conclusion, it can be said that “The resultant structure might be regarded as a textbook sample in mechanical engineering, because the seven hierarchical levels in the sponge skeleton represent major fundamental construction strategies, such as laminated structures, fiber-reinforced composites, bundled beams, and diagonally reinforced square-grid cells to name a few.”</p>
<p>Now let’s concentrate more on the fibers (or spicules) that anchor the cage to the sea floor. These anchorage spicules (a term used for describing the skeletal structures of sponges which comes from the Latin word speculum, meaning the head of a spear or arrow)* are 5-15 cm in length and 40-70 um in diameter. In the above discussion we have briefly discussed the cross-sectional structure of these fibers that gives them their flexible, but resistant nature. Here we will focus on the optical properties of these spicules. But before doing so, let’s briefly explain how optical fibers work.</p>
<p>Optical fibers are silica fibers of a 5 to 80 um diameter that are coated with a cladding layer; light waves can travel in these for long distances by constantly bouncing off the cladding. The reason for this is the refractive index difference between the silica core and the cladding layer. Refractive index (n) is a measure of the ability of a medium to change the phase velocity of light and cause the light waves to bend while leaving one medium and entering another (refraction); in the case of fiber optics, leaving the core and entering the cladding. However, if the refractive index of the second medium is lower than that of the initial one, the incident light waves that have an incidence angle higher than a critical value or critical angle can be reflected back to the first medium and this is what happens in fiber optics (See red ray in figure 2). If the core diameter is small (5-10 um), light rays can propagate only through a single path in the fiber (which runs parallel to the fiber axis), hence these type of fibers are called single-mode fibers (See Figure 2a). If the core diameter is larger however, (60-80 um) several paths are accessible, and more paths will have incidence angles that are greater than the critical angle, hence they are called multi-mode (See Figure 2b).</p>
<p>Now with this information in mind, let’s have a look at the characteristics of the anchoring spicules of the Venus’ Flower Basket. First of all, as mentioned in the previous discussion, the lamellar structure of these spicules prevents crack propagation, which is the main failure mode of commercial silica fibers. This lamellar structure, however, also determines the dependence of the optical behavior of the spicules on the environment in which they are embedded. For instance if the spicules are embedded in an epoxide medium with a refractive index of 1.57, the spicule as a whole would not be able to act as an optical fiber, due to the smaller refractive index of the cladding. However, since the core region of the spicules has a slightly higher refractive index than that of the cladding, the core acts as a single mode fiber in such an environment (see Figure 2a). In sea water-the spicules’ native environment-which has a refractive index of 1.33, the whole spicule acts as a multimode fiber, since the refractive index difference between the core and the cladding is much smaller than that between the cladding and the surrounding sea water.</p>
<p>Another advantage of these spicules over man-made fibers is their formation/production parameters, which are ambient temperature and pressure; these enable the introduction of impurities into the silica. Though at first it may not sound as if impurities are a positive characteristic, these impurities are very important for increasing the refractive index of silica and act as dopants (impurity elements added to a semiconductor lattices in low concentrations in order to alter the optical/electrical properties of the semiconductor). The core section of the spicules, for instance, shows increased sodium concentration, which is the cause of the higher refractive index of this section. Such dopant introduction in the silica during the fabrication process, however, is not possible in the case of man-made fibers, due to the very high processing temperatures.</p>
<p>In addition to this, the spicules have crown-like caps at their base and thorn-like structures throughout their middle section. While the crown-like termini most probably are used to anchor the sponge to the ocean floor, it has also been shown that the waveguiding efficiency of the spicules increases when the illumination comes through the end that has the crown-like structure. Hence, it has been proposed that this structure may be acting as a light harvesting lens. The thorn-like structures, on the other hand, share the lamellar construction of the spicule body, and the light guided through the body branches out to these spines and emerges at the tip. Since sea water comes into contact with the tip at an almost perpendicular angle to the guided light, the coupling is pretty efficient. Hence the combination of crown-like ends and thorn-like structures forms optical networks that collect and distribute light. However, at the depths inhabited by the Venus’ Flower Baskets there is no accessible light source. If one accepts the fact that there is no waste in nature-whether one believes in “creation” or “evolution”-the existence of such an advanced network-like structure as a part of a sponge-the most primitive animal-is at least thought-provoking. In the case of sponges that dwell in shallower waters with similar spicules, it has been postulated that such spicules gather and provide sunlight for the sponge’s endosymbiotic algae. However, at the depths at which the Venus’ Flower Baskets live, direct sunlight is not available. However it has been suggested that if light sources, such as bioluminescent microorganisms (bioluminescence is the production and emission of light by a living organism as the result of a chemical reaction during which chemical energy is converted to light energy) or chemiluminescence (emission of light as the result of a chemical reaction) exist, their light may be efficiently distributed by the sponge and act as an attractant for juvenile shrimp that are searching for a host. But for now these suggestions are just speculation and merit further investigation.</p>
<p>Before concluding this section, we should also note that, as a natural outcome of their construction/composition, these spicules do not have as great a transparency as their industrial counterparts and light cannot be transferred over long distances with them. However, it seems this is not a problem for the Venus’ Flower Basket as, apparently, they just need fibers of 5-15 cm to survive and it is the scientists who need to figure out a way to incorporate the traits of the Venus’ Flower Basket into industrial fibers.</p>
<h3>The love</h3>
<p>As mentioned in the introduction, the Venus Flower Basket hosts a pair of mated shrimp. These belong to the family of Spongicolidae, the Spongicala japonica. These shrimp, which can be as “big” as 9 mm in length, spend most of their lives in their host sponge. Though studies about them are limited, it is believed that before permanently being entrapped in their host, the shrimp have two free- living periods. The first one is just after hatching when they are small enough to exit through the mesh of the sponge. During this period they exit and re-enter their cages and live in a group with their parents and other juveniles. Studies suggest that the females generally stay with their parents until sexual maturity, whereas the males tend to leave their original host and live a solitary life until they reach a length of about 4 mm.</p>
<p>The second free-living period comes at the time of sexual maturity, when it is believed that the male and female mate outside and then invade a host, or the female searches for a host that is already occupied by a solitary male. During this stage, the shrimp have a body length of 3.5 to 6.5 mm which is bigger than the mesh size of the host sponges. Though this seems puzzling, it is thought that the mated shrimp enter the sponge in its flexible stage-when it may be easier to penetrate through the mesh-and get trapped there “forever” as the sponge grows older and stiffer. In fact this theory is supported by the finding that several flexible sponge specimens host solitary and young mated shrimp, whereas in the stiff specimens only very few solitary and young mated shrimp have been observed.</p>
<h3>References</h3>
<p>1. “Biological glass fibers: Correlation between optical and structural properties.” J. Aizenberg, V. C. Sundar, A. D. Yablon, J. C. Weaver, and G. Chen, Proc. Nat. Ac. Sci. 101 3358 (2004).</p>
<p>2. “Skeleton of Euplectella sp.: Structural hierarchy from the nanoscale to the macroscale.” J. Aizenberg, J. C. Weaver, M. S. Thanawala, V. C. Sundar, D. E. Morse, P. Fratzl, Science, 309 275 (2005).</p>
<p>3. “Fibre-optical features of a glass sponge &#8211; Some superior technological secrets have come to light from a deep-sea organism.” V. C. Sundar, A. D. Yablon, J. L. Grazul, M. Ilan, J. Aizenberg, Nature 424 899 (2003).</p>
<p>4. “Skeletal growth of the deep-sea hexactinellid sponge Euplectella oweni, and host election by the symbiotic shrimp Spongicola japonica” (Crustacea: Decapoda: Spongicolidae). T. Saito, I. Uchida and M. Takeda J. Zool., Lond. 258 521 (2002)</p>
<p>5. “Pair formation in Spongicola japonica (Crustacea: Stenopodidea: Spongicolidae), a shrimp associated with deep-sea hexactinellid sponges.” T. Saito, I. Uchida and M. Takeda J. Mar. Biol. Ass. U.K. 81 789 (2001).</p>
<h3>Note</h3>
<p>*. Also defined as, one of the minute calcareous or siliceous bodies that support the tissue of various invertebrates (Merriam-Webster’s English dictionary)</p>
]]></content:encoded>
					
		
		
			</item>
		<item>
		<title>Spiders Expand New Horizons in Fiber-Optic Technology</title>
		<link>https://fountainmagazine.com/all-issues/2005/issue-49-january-march-2005/spiders-expand-new-horizons-in-fiber-optic-technology/</link>
		
		<dc:creator><![CDATA[Louima Cunningham]]></dc:creator>
		<pubDate>Sat, 01 Jan 2005 00:00:00 +0000</pubDate>
				<category><![CDATA[Issue 49 (January - March 2005)]]></category>
		<category><![CDATA[enable]]></category>
		<category><![CDATA[environments]]></category>
		<category><![CDATA[fiber]]></category>
		<category><![CDATA[fibers]]></category>
		<category><![CDATA[human]]></category>
		<category><![CDATA[hunting]]></category>
		<category><![CDATA[light]]></category>
		<category><![CDATA[microscopes]]></category>
		<category><![CDATA[nanometers]]></category>
		<category><![CDATA[optic]]></category>
		<category><![CDATA[produce]]></category>
		<category><![CDATA[proof]]></category>
		<category><![CDATA[radius]]></category>
		<category><![CDATA[research]]></category>
		<category><![CDATA[Science]]></category>
		<category><![CDATA[spider]]></category>
		<category><![CDATA[spiders]]></category>
		<category><![CDATA[technology]]></category>
		<category><![CDATA[thread]]></category>
		<category><![CDATA[tubes]]></category>
		<guid isPermaLink="false">http://107.21.79.195/all-issues/2005/issue-49-january-march-2005/spiders-expand-new-horizons-in-fiber-optic-technology/</guid>

					<description><![CDATA[Spiders, known to be horrifying animals to many, are recognized by us for their role in the ecological balance. If spiders were to be removed from the natural food chain, and thus, from the ecological balance, an explosion in the flea and insect populations would be inevitable. These masters of hunting are inspired with various [&#8230;]]]></description>
										<content:encoded><![CDATA[<p>Spiders, known to be horrifying animals to many, are recognized by us for their role in the ecological balance. If spiders were to be removed from the natural food chain, and thus, from the ecological balance, an explosion in the flea and insect populations would be inevitable. These masters of hunting are inspired with various hunting strategies. The spider is possessed with the ability to fabricate a web spun from a multi-featured thread, which it utilizes in hunting, defense, and reproduction. Some recent research projects have uncovered some significant features of the spider web; these are being employed in ways that will be beneficial to human life. The thin, elastic, durable thread that is capable of stretching up to three times its length which forms the spider web has been the subject of many research projects. One example of how these have been turned to use for human beings is the bullet-proof vests which are designed by imitating the formation of the spider web; these are superior to metal bullet-proof vests in terms of rigidity and weight.</p>
<p>Our Creator has solved every potential problem which living things might experience by creating one optimal solution among every alternative.These perfect solutions open new horizons for men, and they also act as guides in the development of science and technology. The book titled “Engineering in Nature” details many striking examples.1</p>
<p>In recent research, it has been discovered how the thread of a spider can contribute to fiber-optic technology. A crucial challenge in photonic technology is to produce the tiny optic fiber that is used as a conductor for a light beam in nano-scaled optic circuits. Yushan Yan, of the University of California in Riverside, has taken an important step forward in this technology by covering the thread from a spider web with a glass-like material and then removing the thread after the material has hardened. By utilizing this technique, it is possible to produce threads that are 1/50000th the diameter of human hair and that have a radius of 2 nanometers (1 nanometer being one billionth of a meter).</p>
<p>Not only will this discovery be applicable in photonic technology, it will also increase the resolution in optical microscopes, or, alternatively, these threads could be turned into nanoscale test tubes in a new breed of sensors that can suck up single molecules of a particular chemical.</p>
<p>A research group at the University of California cut a thread 1 centimeter long from the web of the giant spider of Madagascar, the Nepila Madagascariensis, and pasted the two ends of the thread to a card. Then they repeatedly dipped this thread into tetraethyl orthoslicate solution. After this, the thread that had undergone this process was dried and heated to a temperature of 420 Celsius. The string decreased by one fifth of its original radius and the process resulted in the production of tiny tubes with a radius of one micrometer.</p>
<p>There are plans to make use of the web of the Stegodyphus Pasifiu-a spider which uses a thread of a radius of 10 nanometers and which is found in the Middle East and Southern Asia. This will enable scientists to use thinner fibers. After heating, a thread with a radius of 2 nanometers is attained. Until this latest finding, it was only possible to produce fibers with an interior radius of 25 nanometers.</p>
<p>Fiber optic researchers do not hide their enthusiasm for this new simple and cheap technology. It is expected that it will be used in the field of supra-molecular chemistry; that is the study of very miniature environments. In these environments the reaction-speeds increase and completely different reactions occur. For such experiments carbon nano-tubes are being used at the present time. The tubes made from fibers obtained from spider webs will enable scientists to create more sensitive environments. It is also thought that it will be possible to create microscopes with a higher resolution by using tinier fiber optic catheters.</p>
<p>Such microscopes would be used to observe events that are shorter in duration than the wavelength of light, yet at the same time, these microscopes would not cause the sample to be harmed. Electron microscopes harm the sample since the features of the technology used necessitate this. Currently, these microscopes use a scope that has been made from very thin glass tubes. These fibers are relatively thick, measuring about 100 nanometers in radius. Yet, by means of this new technology, these new microscopes can be developed and biologists will have brand new opportunities to study events that have not been visible before. Surely, it is not possible to say that the immaculate biological structure and incredibly small thread employed by the spider can be explained by simply putting its creation down to chance or by stating that it is a product of nature.</p>
<p>These perfect examples that can be observed in nature will lead to fundamental changes in our understanding of the universe; they will enable great leaps in terms of making our life more comfortable and, most importantly, they will be helpful in realizing how the Divine Power and Art can be present together and be in harmony.</p>
<h3><b>References</b> </h3>
<ul>
<li>M. Sami Polatoz, Tabiatta Muhendislik [Engineering in Nature], Kaynak, Istanbul: 2003.</li>
<li>Danny Penman, Spiders Weave a Web of Light, New Scientist,</li>
<li>22 March 2003, p. 20.</li>
</ul>
]]></content:encoded>
					
		
		
			</item>
	</channel>
</rss>
