Both of these ladies were ecologically conscientious, even though they never received an education about the environment. Despite this, I would have thought that by now, decades later, there would be more of a focus on environmental education (EE) in schools. And though a search on Google Scholar shows a lot of research about EE, it doesn’t show a ton of applications of EE in contemporary schools.

EE perspectives are present in many ideologies, such as ecopedagogy, egocentrism, anthropocentrism, autopoiesis intrinsic value theory, ecofeminism, green socialism, eco-Marxism, etcetera (Lummis, 2002). And yet I am interested in EE programs, and there are shockingly few of them.

Value education is based on cognitive and affective development. The main aim of education, according to value education, is to create a “good citizen” for a “good society” (Lickona, 1999; Rest, 1974). The most important side of these education programs is to develop self-awareness, helping people to become aware of the larger world (Kollmuss and Agyeman, 2002, p.257; Rest, 1974, p.461).

Awareness is directly related to ego development, and to thinking critically. Experimental programs are needed, and a person’s cognitive structure needs to interact with the environment to develop their ego. The main subject here is being “interactionist”  (Rest, 1974). I would like to define this term, environmentally, as “to have an interaction with the natural environment and to have individual outputs.” I understand that in terms of EE, value education should trigger environmental awareness.

There are experimental studies ongoing in the hopes of achieving environmental awareness. Unfortunately, none of these studies mention value education. This is a shame, as the typical properties of value education (Rest, 1974) and EE overlap: to develop responsibility and awareness, cooperative learning, to think critically, and to develop behavioural changes in the long-term.

Value education should be an important part of EE because educational philosophy plays a critical role in shaping teaching programs. Teachers and administrators should first think about the philosophical roots of their aims. Rest (1974) says that value education is based on the thoughts of Plato, Hegel, Dewey, and Piaget; in other words, “progressivist” approaches. Pierre Walter (2009) also mentions the progressivist origins of EE.

We should not forget that we first encounter value education in our families. Value education and EE may also be evaluated in terms of education children learn from watching adults/parents. A lot of research highlights the importance of parental education (Kasapoglu and Turan, 2008; Gokdere, 2005).

Unfortunately, current research shows there is a gap between theory and practice in EE (Bolstad and Baker, 2004; Elliott, 1999; Hart and Nolan, 1999; Mansaray, Ajiboye and Audu, 1998). This gap may close with the use of value education, but there is significant overlap between the two disciplines. Using one to develop the other is a method that has not yet been tried, but could lead to future improvements in both disciplines.

References
Gokdere, M. (2005). “A Study On Environmental Knowledge Level Of Primary Students In Turkey”. Asia-Pacific Forum on Science Learning and Teaching, Volume 6, Issue 2.
Hart, P. & Nolan, K. (1999). “A Critical Analysis Of Research In Environmental Education”. Studies in Science Education, Volume 34’ Issue 1, p. 1-69.
Kasapoglu, A., & Turan, F. (2008). “Attitude Behaviour Relationship In Environmental Education: A Case Study From Turkey”. International Journal of Environmental Studies, Volume 65, Issue 2, p. 219-231.
Kollmuss, A., & Agyeman, J. (2002). “Mind The Gap: Why Do People Act Environmentally And What Are The Barriers To Pro-Environmental Behaviour?”. Environmental Education Research, Volume 8, Issue 3, p. 239-260.
Lickona, T. (1999). “Character education: The cultivation of virtue”. In Charles M. Reigeluth (Ed.), “Instructional design theories and models (Volume II)”. Lawrence Erlbaum Associates, New Jersey.
Lummis, G. (2002). “Globalisation: Building A Partnership Ethic For A Ecopedagogy In Western Australia”.  Australian Journal of Teacher Education, Volume 27, Issue 1, Article 2, 1-1.
Rest, J. (1974). “Developmental Psychology As A Guide To Value Education: A Review Of "Kohlbergian" Programs”. Review of Educational Research, Volume 44, Issue 2 (Spring, 1974), p. 241-259.

“Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.” Cree Indian Proverb

The table I have under my laptop while writing this article, the materials used for my laptop, the cover case for my phone, the pen I have by my phone, the package for the mail I have received, the dividers I have in my notebook, the hair dryer I have for drying my samples before performing FT-IR on my samples, the FT-IR machine itself … They are all made up of plastics. I could go on and on, giving examples of what I observe in my immediate environment made of plastics. It would not be exaggerated to say that after the Stone Age, Bronze Age, and Iron Age, we are now living in the “Plastic Age” given the fact that the production of plastics has increased from 1.5 million tons per year in the 1950’s to 260 million tons per year in 2007.1 The majority of plastics we use in our daily life are petroleum-based plastics. What that means is, the starting materials of these plastics are chemicals derived from crude oil. There are some major concerns related with these petroleum based plastics – the Earth may run out of oil one day, or the questionable durability of how these plastics biologically degrade. Further environmental concerns exist, such as the toxic additives these plastics contain, including plasticizers like adipates and phthalate. Burning these plastics can release billions of tons of toxic pollutants every year; moreover, most plastic production reactions are done in toxic solvents, so the disposal of these solvents becomes a problem.2 Reflecting on it, it’s an incredible mercy that we have been able to get away with all the waste we have produced up to this point. But the question is: how much longer can we get away with such wasteful behavior?

One of Paulo Coelho’s passages from his book The Winner Stands Alone exactly describes my attitude and desire to “go green.” My heart pounds as I read the sentences that so touched me:

It seems now that-despite wars, famine in Africa, terrorism, the violation of human rights, and the arrogant attitude of certain developed countries-our main preoccupation is saving poor planet Earth from the many threats created by human society. “Ecology. Save the planet. How ridiculous.”

Hamid knows, however, that there’s no point in fighting the collective unconscious. The colors, the accessories, the fabrics, the so-called charity events attended by the Superclass, the books being published, the music being played on the radio, the documentaries made by ex-politicians, the new films, the material used to make shoes, the new bio-fuels, the petitions handed in to members of parliament and congressmen, the bonds being sold by the largest of the world banks, everything appears to focus on one thing: saving the planet. Fortunes are made overnight; large multinationals are given space in the press because of some completely irrelevant action they are taking; unscrupulous NGOs place advertisements on the major TV channels and receive hundreds of millions of dollars in donations because everyone seems obsessed with the fate of the Earth. Whenever he reads articles in newspapers or magazines written by politicians using global warming or the destruction of the environment as a platform for their electoral campaigns, he thinks:

“How can we be so arrogant? The planet is, was, and always will be stronger than us. We can’t destroy it; if we overstep the mark, the planet will simply erase us from its surface and carry on existing. Why don’t they start talking about not letting the planet destroy us? Because ‘saving the planet’ gives a sense of power, action, and nobility. Whereas ‘not letting the planet destroy us’ might lead to feelings of despair and impotence, and to a realization of just how very limited our capabilities are.” 3

On that note I would like to share some amazing facts I found while searching articles written on bacterial biopolymers, but first of all I would like to introduce some definitions on the concepts I will be writing about.

Plastics have many definitions, but usually, in a daily conversation, plastics mean “anything that can be molded or shaped.” Scientifically, a plastic is a sub category of a polymer. Poly- meaning “more than one” and -mer meaning “member of a particular group.”[4] Basically, a polymer is a naturally occurring or synthetic compound made of many relatively simple repeating units that are linked together in the same fashion, forming a carbon rich backbone in most cases. For example, PVC is a well known synthetic polymer, in which the monomer (the repeating unit) as seen in Figure 1 is repeated several times. A well known natural polymer is cellulose, in which the monomer as seen in Figure 2 is repeated several times.

Here it is important to note the difference between a polymer and a plastic. All plastics are polymers, as in the example of PVC, whereas not all polymers are plastics, as in the example of cellulose. The combination of the chemicals, and the type of bonds these chemicals are linked to each other by, determines the properties and applications of the polymers. The molecular weight of the polymer depends on how many times the monomer repeats itself. The molecular weight of polymers can be controlled during production with chemical techniques. One significant difference between natural vs. synthetic polymers is the molecular weight distribution. When the polymer is synthesized in the lab, the polymer product is a combination of different molecular weight chains. In other words, when a polymerization reaction takes place, lots of polymer chains are produced and one chain is never the same length or weight as another. Instead, there is a molecular weight distribution as seen in Figure 3, where most of the polymer chains in the solution have a molecular weight close to the value of Mw. So in the solution, we will have polymer chains that have molecular weights close to each other, and some extreme short or long polymer chains. It is impossible to synthesize a polymeric solution where all the polymer chains are of identical length and weight; therefore, we speak about the average molecular weight when the case is synthetic polymers. However, when we look at any polymer produced in nature, we see that the polymer chain length and molecular weight are the same every time the polymer is produced. So instead of a molecular weight distribution, natural polymers have a molecular weight value. This is important because the narrower the molecular weight distribution is, the better.

When talking about bio plastics, it is important to make the differentiation between bio-derived plastics and bio-based plastics. As Dr. R. Narayan explained in his talk at Johnson County Community College[5] , bio-derived plastics means that the plastic is isolated from a living organism, meaning that the living organism performs the polymerization reaction and then you extract the polymer from the organism.

On the other hand, bio-based plastics mean that the starting material of the plastic is derived from a living organism instead of a petroleum-based material, but it is polymerized into a plastic by humans. Therefore, not all bio-based plastics are biodegradable; however, the fact that the starting material is from a plant that can be replaced in a couple of years rather than a petroleum-based product which can only be replaced after a couple million years, drives motivation for their usage. There is the ethical concern that bio-based plastics are usually made from food sources, such as corn, however Dr. R. Narayan, who is one of the leaders in the field, argues that if the situation is handled appropriately, this should not be a problem. He argues that one up-side of the situation would be to increase values of crops and the prevention of mass migration to big cities. It’s your call to decide which side you favor more.

What is more interesting to me is the polymers being created in nature. A chemistry doctorate, Dr. Lon J. Mathias, writes that “We humans make nylons in tons per day in huge chemical plants where simple molecules are joined together in large quantities to give products that we need or want. Nature is much more careful and concise in how she does things. For a living organism to make an enzyme, another enzyme or active species must be involved. The synthesis always involves a template, or recording, of how the individual amino acids are to be joined together to give the final polymer. The enzyme adds a single amino acid, one at a time, as indicated by the mRNA. This is a slow and tedious process and takes a long time. Sometimes the enzyme gets frustrated, waiting for the right amino acid to come along, and slaps a wrong one on instead. To compensate for this, the enzyme is made to back up occasionally to check its work. If it has made a mistake, it has a process for clipping out the wrong amino acid and inserting the right one. We humans never do this. If we make a mistake, we simply grind it up and throw it away.”6

Dr. Mathias goes on, comparing the manufacturing conditions between nature’s form of polymerization and humanity’s. He says polypeptides in nature are synthesized in water, whereas we synthesize our polypeptides in toxic organic solvents. “This leads us to a problem: what do we do with the organic solvents when we’re through? Sometimes we burn them, but more commonly we try to recycle these materials, which not only are getting more expensive to buy in the first place (compared to cheap water, which is everywhere, or almost everywhere) but are also a responsibility for their recycling, purification, and final disposal. An example of how nature uses water in this way, and one which we still haven’t figured out, is the production of spider silk. Spiders spin their webs from solutions of polypeptides in water. These solutions are squeezed through the spider’s tiny spinneret and elongated quickly to form the spider webs which we’ve all seen and sometimes become tangled in. What’s really weird is that, once these spider webs form, they are no longer soluble in water. If we could just figure out how spiders first make spider silk in water and then spin their webs from it, we could make nylon the same way. This might save us a lot of waste disposal problems, and money.”6

Another spectacular creation in nature is polymers produced in bacteria which can be used as plastics once isolated from the bacteria. A wide range of biopolymers that are synthesized in bacteria serve diverse biological functions and have material properties suitable for numerous industrial and medical applications.7 Different carbon sources are efficiently converted into a diverse range of polymers with varying chemical and material properties.7 To be a little more specific, four major classes of polymers are produced by bacteria: polysaccharides, polyesters, polyamides and inorganic polyanhydrides (such as polyphosphates).7 These polymers serve various biological functions, for example, as reserve material or as part of a protective structure, and can provide a substantial advantage for bacteria under certain environmental conditions.7 Some of these biopolymers can be isolated from bacteria and can be used as plastic. Biopolymers are, by definition, biodegradable, and so their application as commodity products becomes increasingly attractive in view of the desire to avoid the use of recalcitrant oil based polymers that will accumulate in the environment.7 Biodegradable means that when exposed to the microbial flora present in a given environment (for example, in soil or water), biopolymers are fully degraded and mineralized to CO2 and H2O.5 The reason biopolymers are 100% degradable is, as they are produced in bacteria as storage material, they have sites where bacterial enzymes could attack to break them down when they search for nutrients. Whereas other polymers – even bio based polymers – will not have these enzymatic sites, so they are not always biodegradable.

One popular class of polymers produced by bacteria which can be used as plastics is called polyhydroxyalkanoates (PHA’s). PHA’s are a class of polymers produced in nature by the bacterial fermentation of sugar or lipids. They are produced by bacteria to store carbon and energy when there is a nutrient lacking from the environment. Many kinds of bacteria are able to produce PHA’s, such as soil inhabiting bacteria, and many bacteria in activated sludge, high seas, or extreme environments. 8 As we store fats in our bodies, the bacterium store PHA’s. In an environment that contains all of the necessary nutrients, bacteria grow and reproduce – in other words they produce biomass. However, when subjected to specific nutrient depletion (nutrients such as nitrogen or phosphorus) and excess amount of carbon resources, the bacterium starts storing PHA granules (Picture 3). The moment the missing nutrient is introduced back into the environment, the bacterium starts degrading the PHA granules and continues to produce biomass. Therefore, by manipulating the nutrient resources in the environment and providing optimum conditions, bacterium can be pushed to produce PHA’s.[9]

There are metabolic pathways involving various enzymes for the conversion of carbon sources to polymers. Scientists have been trying to genetically engineer bacteria for the increased production of these polymers. In some cases it is possible to over-express the key enzymes in the pathways to achieve increased production of PHA. However, this kind of research takes a lot of time and effort because altering biological activity is a very complicated process and in most cases, cells give unpredictable responses to alterations. By feeding the bacterium with different carbon sources at different conditions, it is also possible to alter the composition of the polymers. Moreover, different strains of bacterium produce different types of polymers; therefore, the range of biopolymer research is very wide. With over 150 different PHA monomers (the repeating unit of polymers) being reported, PHA with flexible thermal and mechanical properties have been developed. 7 Such diversity has allowed the development of various applications.

During his speech at the “2nd International PLASTiCE Conference Trends in Bioplastics” in Slovenia, 9 Dr. Martin Koller explained that there are two types of PHA’s that a microorganism produces. The first type are short length PHA’s (3-5 carbons in the backbone) and the second type are medium chain length PA’s (6-12 carbons in the backbone). While the medium chain length PHA’s can be used for biodiesel production, the short chain length PHA’s can be used as thermoplastics (plastics that can melt with heat, and can therefore be processed with the help of heat). These thermoplastics can be isolated from the organisms they are produced in by solvent extraction, mechanical disruption, or by using hypotonic media (having the lower osmotic pressure of two fluids) for cells that have high intracellular osmotic pressure.9 In the last case, the cells will explode due to the pressure difference and release the PHA’s; deionized water can be used as the hypotonic media. However, only specific strains can be treated with this method. At the moment, the most common technique used for extraction is solvent extraction. These solvents – such as chloroform or dichloromethane – are generally toxic, therefore creating a contradiction with the point of producing biopolymers.

Although not mainstream, some of these bacterial plastics are produced in the industrial world.8 The simplest and widest application for bacterial plastics is for packaging purposes. They can also be used in therapeutic applications, as they are generally biocompatible. Drugs can be incorporated into them, therefore as they biodegrade, they release the drug in a controlled time frame.9 For example, Dr. Martin Koller and his group have just finalized a project called “BRIC – BioResorbable Implants for Children,” funded by the Austrian Research Promotion Agency (FFG).10 Their purpose was to isolate a biocompatible polymer produced from bacterium which could be degraded and removed from the body within a certain time. The point of this project is based on the fact that in contrast to the traditional implants that need to be removed from the body after a certain amount of time, such as plates, screws or pins, the newly developed implants could be degraded and removed from the body naturally, preventing the need for a second surgery. This is a great advantage, especially for children, who would suffer greatly from additional surgeries.

Bacterial bioplastics have many other applications; however the biggest obstacle for their usage is the cost of production. During his speech, Dr. Keller stated the production of bacterial bioplastics is around five times more costly than petroleum based plastics. Most of the cost is related with the bioreactors needed to grow the bacterium and the solvents used to extract the polymers. The scientists are hoping to develop new techniques to reduce the cost of the polymers.

It is breathtaking that these creatures we cannot even see with the naked eye have been synthesizing polymers as well as we do, if not even better, and for a lot longer than us. The polymers they synthesize are completely biodegradable, have a constant molecular weight, and do not require toxic chemicals for their production, unlike the synthetic polymers we produce in the lab. They don’t harm nature as we do. And THAT is powerful.

References

1- Simon, Tristan (2007). “Experience Curves in the World Polymer Industry” Utrecht University, Netherlands.

2- Lei Pei, Markus Schmidt and Wei Wei (2011). “Conversion of Biomass into Bioplastics and Their Potential Environmental Impacts, Biotechnology of Biopolymers.” InTech.

3- Coelho Paulo(2008), “The Winner Stands Alone.” pg: 139.

4- http://dictionary.reference.com/

5- Narayan, Ramani (2013)”Bioplastics and Reducing Carbon Footprint.” JCCC Video. Johnson County Community College, USA.

6- Mathias, Lon J. (2005).”Natural Polymers.” Polymer Science Learning Center. The University of Southern Mississippi, USA.

7- Rehm, Bernd H.A.(2010). “Bacterial polymers: biosynthesis, modifications and applications” Nature Reviews Microbiology. Massey University, New Zealand.

8- Chen, Guo-Qiang (2010). “Plastics Completely Synthesized by Bacteria: Polyhydroxyalkanoates”. Plastics from Bacteria: Natural Functions and Applications, Microbiology Monographs, Springer. Tsinghua University, China.

9- Koller, Martin (2012). “Polyhydroxyalkanoates: Biodegradable polymeric materials from renewable resources” Plastice Project Video. 2nd International PLASTiCE Conference Trends in Bioplastics, Slovenia.

10- No name (2013).”Plastics from Renewable Raw Materials:Body automatically breaks down implants” Graz University of Technology, Austria.

11- Nishiyama, Yoshiharu; Langan, Paul; Chanzy, Henri (2002). “Crystal Structure and Hydrogen-Bonding System in Cellulose Iβ from Synchrotron X-ray and Neutron Fiber Diffraction”. J. Am. Chem.The University of Tokyo, Japan.

12- Ritter, Stephen(2005). “Green Success.” Science and Technology. pg: 40-43.

13- Waters Co. (2013). “GPC-Gel Permeation Chromatography”. Web.

This beach is one of the starkest reminders of the extent of human impact on oceans.

Kamilo Beach is not the only junk beach in the world. Similar trashed beaches exist in the Azores in the Atlantic Ocean and Baja California. The litter on these shores and in the seas is so excessive that it is even visible to the people on land. Out towards the open seas, huge garbage patches fill the middle of the ocean, like wide loops of rotating currents, also known as gyres (www.marinedebris.noaa.gov).

Gyres

Gyres are major surface currents that circle the oceans. They are driven by persistent winds and the Coriolis Effect which is caused by the Earth’s rotation. The human impact on oceans is displayed by the gyres. They gather trash released into seas from countries around the oceans and through rivers they carry the floating objects and trash spewed from fallen shipping containers.

This was dramatically demonstrated when a cargo of sports shoes were lost in the sea in 1990. The shoes floated and drifted with the currents. Eventually thousands of them washed up on shores from Alaska to California. The manufacturer provided the serial numbers of the lost shoes. Beachcombers responded to calls by researchers regarding the time and location that they found the beached shoes. When all the data points were combined, the gyre’s circulation period over 3 years was obtained. Tracking a spill of bathtub toys provided similar results.

Outsourcing of manufacturing overseas and worldwide supply chains are made possibly by networks of container shipping lines. For reasons of economies of scale, the containers are stacked precariously high on the decks. At rough seas in the open ocean, some of these containers are washed overboard. There are about 10 million 40-foot cargo containers in use in the world. Every year a few thousand of them are washed off the decks of ships in heavy seas. The lost cargo rarely becomes news; it often stays confidential among the ship owner, the importer, the exporter and the insurer. Many of the lost containers sink to the bottom of the ocean. However some of them float and release their contents. This is the source of the flotillas of running shoes, or the toys that get carried away by the currents and winds.

The great garbage patch in North Pacific Ocean covers an area double the size of Texas. Like a conveyor belt, North Pacific Subtropical Gyre rotates clockwise, carrying with it the natural or man-made floating objects. The life span of a gyre is about three years. The floating objects may end washed up at beaches or they may be drifted to the center of the gyre where the currents are weakest. This is where the garbage patch forms—from millions of tons of plastic and other debris covering millions of square miles (www.dels.nas.edu).

Plastics

Plastic nurdles are a significant part of the pollution. These tiny beads are used as raw material in manufacturing. They are carried in container loads across the oceans and are occasionally spilled in large amounts and dispersed at sea.

Compared to organic matter that rots, decays, and gets recycled back into biomass by organisms, plastic is durable. A single plastic water bottle can last for hundreds of years. Suspended in sea water, these plastic particles absorb toxic chemicals. When marine animals consume the floating plastic, disproportionately high levels of these toxic materials are accumulated in their bodies. Some of these animals end up as food on our dinner table. Yes, that plastic tossed into the sea returns back as poisonous seasoning in our diet!

Plastics are contaminating the food chain at different levels. The animals at sea mistake trash for food. The microscopic particles get absorbed by animals filtering sea water for food. Easily mistaken for jellyfish in water, plastic bags suffocate sea animals that ingest them for food. Larger items threaten sea birds and mammals. Seabirds die when their guts get clogged with swallowed plastic items, and other animals starve because their stomachs are full of debris (www.commerce.senate.gov/pdf/marinedebris).

Fishing

A serious source of marine debris is the fishing industry. Numerous fishing nets and floats get lost and are abandoned at sea. These nets, which may extend a distance of many miles, strangle turtles and other sea mammals. Fishing industries should be inspected to keep track of their gear. There are organizations like the Monterey Bay Aquarium (www.montereybayaquarium.org) that distribute information about environmentally friendly fishing. In a free market economy where people vote with their money, consumers should inquire about the sources of seafood and support fishermen that do not leave their nets behind.

Enforcement in open seas requires international cooperation. Vessels should be inspected at their ports of call. Volunteers spotting container ships may record differences in cargo and alert authorities for missing containers. Marine laws, fees, taxes, and insurance premiums can be updated to deter unsafe loading of container ships. In the long run, vessel designs, navigational routes, shipping schedules and weather monitoring should be improved for minimization of cargo loss. An international cooperation is essential to oversee these efforts. The balance sheet of shipping business should include the cost of loss-free transport of containers.

Human negligence

The seas appear to be vast, but we seem to have come to the limits of it by the sheer amounts of garbage dumped into the rivers and by the contamination by marine transportation. These are inescapable reminders that we have reached the limits of this resource. The sea often regurgitates whatever is dumped inside it. This is like a slap on the beach, where the ocean hits back at us with our own trash, not to praise us or show approval, but to bring before our eyes the chaos we have created.

The universe is granted with an internal maintenance system, recycling its own waste products, hence reflecting the absolute purity of the Divine in His creation. The responsibility of humans as “vicegerents” of the earth include using the Earth’s resources without dumping or wasting but safeguarding the environmental balance and acknowledging that every creation has its purpose in being and should be treated accordingly.

The trashed beaches and mid-ocean garbage patches are signs of the deadly and long lasting effects introduced by humans into the seas. This is totally avoidable. We should employ a zero waste approach to our consumption habits. Cost of reusing, recycling and safe disposal of products should be reflected in the price of goods. Laws and regulations should be updated and enforced to minimize the dispersion of long lasting contaminants into the environment. The shipping and fishing industries should be accountable for lost cargo and gear. The seabirds should not starve, and the turtles should not drown due to our negligence.

References

• Auman, H.J., Ludwig, J.P., Giesy, J.P., Colborn, T., (1997) “Plastic ingestion by Laysan Albatross chicks on Sand Island, Midway Atoll, in 1994 and 1995.” in Albatross Biology and Conservation, (ed by G. Robinson and R. Gales). Surrey Beatty & Sons:Chipping Norton. Pp. 239-44
• Spear, L.B., Ainley, D.G. & Ribic, C.A. (1995). “Incidence of plastic in seabirds from the tropical Pacific, 1984–91: relation with distribution of species, sex, age, season, year and body weight.” Marine Environmental Research 40: 123–146
• http://www.washingtontimes.com/news/2003/feb/26/20030226-085636-3495r/
• Ebbesmeyer, Curtis; Eric Scigliano. 2009. Flotsametrics and the Floating World: How One Man’s Obsession with Runaway Sneakers and Rubber Ducks Revolutionized Ocean Science. London: Collins.

Microbes, in particular bacteria, are associated with many diseases, being the deadliest pathogens along with viruses. But, this doesn’t mean that all bacteria are harmful. Indeed, most bacterial colonies that reside in our gut have mutualistic relationship with humans. Our intestines carry approximately ten times more bacteria than the total number of cells in human body. This vast number of bacteria residing in our intestines are not only harmless, but they are also beneficial for us in many ways, by digesting food to supply energy for the body, by outcompeting the disease-causing bacteria in the intestines, and by producing vitamins and hormones. This study brings a new dimension to our understanding of the interactions between the host immune system with the gut microflora. The main components of immune system are the T cells that can recognize the pathogens. Each T cell recognizes one particular pathogen and distinguishes self-cells from the pathogens. In the thymus, T cells that recognize self-molecules are either eliminated or transformed into a special category of T-cells called regulatory T cells (Tregs), whose job is to maintain tolerance towards self-antigens. Lathrop and colleagues demonstrated for the first time that naïve T cells are developed into Tregs in the gut upon encounter of commensal gut bacteria. What is striking is that these Tregs responded to the bacterial antigens, unlike the thymus originated Tregs that were generated by self-antigen recognition. These data suggest that gut bacteria train host’s immune system to be silent against themselves and act only against invading pathogens. Mechanisms involved in distinguishing harmful vs. beneficial bacteria by the immune system may provide new ways of tackling with bacterial diseases.

2- Cancer meets memory

Original Article: Odajima, J. et al., Developmental Cell 21, 655 (2011).

The recent discovery in the field of neuroscience reminded us the phrase “context is everything.” A study conducted by the scientists of Dana-Farber Cancer Institute and Harvard Medical School addressed somewhat contradictive observation that why human brain has high levels of cyclin E protein, a well-known culprit in many cancers. Cyclin E protein plays an important role in cell cycle where it helps to regulate the timing and the frequency of cell division in normally growing cells. However, overexpression of cyclin E has been associated with uncontrolled cell growth in various cancer types. It is surprising that the human brain, which has a group of non-dividing cells, also express cyclin E at high levels. The study showed that when cyclin E deficient mice were analyzed, there was a serious defect in the formation of nerve connections as well as the formation of memory. “It is overexpressed in many different cancers, but it also is expressed in high levels in the human brain. We have found that cyclin E is needed for memory formation and is a very important player,” said senior author Peter Sicinski, PhD, a cancer biologist at Dana-Farber. The study showed that cyclin E achieves its functions in the brain by binding to Cdk5 enzyme whose activity is associated with Alzheimer’s disease. “There is good evidence that hyperactivity of Cdk5 contributes to Alzheimer’s disease and inhibiting this enzyme can ameliorate symptoms in animals,” said Sicinski. “Manipulating cyclin E levels might be another way to accomplish this,” he added.

3- Designing perfect plastic 

Original Article: Read, D.J. et al., Science 333, 1871 (2011).

Plastic is used everywhere in our daily lives. Up until now, production of different types of plastic was done by trial and error. Only a small fraction of these trials give rise to a usable product. After ten years of hard work, scientists have now developed a computer program that can predict properties of plastic without actually manufacturing it. The program has two parts. The first part can predict how a specific polymer will flow based on the connections between the macromolecules that make up the polymer. The second part predicts the shape of these macromolecules when they are made at a chemical level. Using this code, one can effectively construct a recipe book for plastic. This will make it possible to design plastic that can better handle a specific job. It will also be possible to make plastic out of renewable materials instead of oil based materials which will be easy to recycle.

4- The key to long life?

Original Article: Kim, E.B. et al., Nature (published online before print, 2011).

Who would want to live a long life at the cost of looking ugly? One type of rodent species, naked mole rat, seems to have said “yes” to this intricate question. While an average rodent, a house mice or a rat living on streets, can live up to 4 years, naked mole rats can live up to 30 years. Mole rats are hairless, buck-toothed and almost blind rodents that are only found in dry sections of the Horn of Africa. They live in underground colonies with a social structure similar to ant colonies. There is a queen rat that chooses to mate with only few males, and rest of the colony takes the big responsibility of maintaining and protecting the colony. Scientists have always been puzzled with the extraordinary life span of these exotic animals and they finally generated the complete gene map of these intriguing animals. A quick look of the genomic map revealed that many genes associated with vision, circadian rhythms, perception of pain and perception of bitter tastes seem to be completely turned-off. Perhaps, these specific modifications allow animals to tolerate harsh living conditions and help them to adapt a lifestyle which lacks so-called the luxuries and expectations of a normal animal. Scientists believe that comprehensive analyses of naked mole’s genetic map might shed light on fundamental cellular mechanisms that are disrupted in aging and aging-related diseases.

Many people probably would agree that the transistor was the greatest technological invention of the twentieth century. The first transistor, invented by Jack Kilby and Robert Noyce in 1958, was made from silicon. Even though integrated circuit technology has advanced to the level of putting millions of transistors on a fingernail-sized chip, transistors are still made from silicon. Now, however, both the scientific community and the high-tech industry are very excited about something new: plastic electronics. For many of us, this might sound like an oxymoron, for we know plastic only as an insulator. So how can a protective substrate or a carriage box to the actual electronic device be converted into an electronic device?

The story of plastic electronics started late 1970s with Alan Heeger, Alan Macdiarmid, and Hideki Shirakawa. These scientists demonstrated that the molecular structure of certain polymers (plastics) can be manipulated and then used as conductors. The Swiss Academy of Sciences was somewhat slow in recognizing their work, for they were awarded the Nobel prize in chemistry only in 2000. Nevertheless, the scientific community did not wait for the Nobel committee’s recognition of plastics. Since 1977, plastic has become probably the most common material in our daily lives.

Silicon versus plastic

All computer chips are made out of silicon (semiconductor) and aluminum (metal). Silicon is a great material for integrated circuits, because it is available, can be acquired in an extremely pure state (single crystal or amorphous), and has a very high mobility (the speed that electrons can travel through material). This mobility, in turn, determines the device’s switching speed. However, silicon has one important drawback: It is not easy to process.

Integrated circuit technology can deposit millions of silicon transistors on a single chip. However, the procedure for making these devices usually requires facilities worth billions of dollars, for silicon has to go through complicated photolithography procedures under clean room conditions before it can be incorporated into a device. But is it really worthwhile to spend billions of dollars on such facilities? The answer probably looks obvious, since Intel remains one of the world’s largest companies. However, we do not really need such a high quality in many of the applications for which silicon is used. So if there is something cheaper that can do the job perfectly, why not use it? Plastic is far cheaper, but not so sophisticated an alternative.

Plastic is cheap because billion-dollar facilities are not required to convert it into a device. In fact, the technology needed to process plastic into an electronic device is only slightly more advanced than an ink-jet printer. Electronic circuits are printed on an insulating polymer, and then certain parts of the polymer are exposed to UV light in order to convert the insulating polymer into a conducting polymer. The result is a device in which only the parts that we want to conduct are conducting. Moreover, these conducting parts sit on a protective insulating sheet of plastic. That is pretty much all we need for many applications.

The case for plastic

Plastic has two advantages over silicon: price and flexibility. Like other inorganic elements, silicon has strong covalent bonds between its atoms. As these bonds are rigid, they cannot bend or stretch. Plastic has very loose molecular bonds that can tolerate a significant amount of bending and stretching. Flexibility combined with electronics implies applications like flexible displays that can be rolled up and taken somewhere else, reloadable electronic newspapers that can be bent like paper, disposable mobile phones, and many others.

So if plastic is that good, why is it not the electronics industry’s standard material? For one simple reason: Plastic’s loose molecular bonds, which make the material so flexible, make it more difficult for the electrons to travel through it. Thus, plastic devices are slower than silicon devices. Until several years ago, the mobility of a typical conducting plastic used to be around 0.1 cm2/volts, whereas crystalline (best) silicon could reach 1000 cm2/volts at room temperature. Recently, a new class of polymers (pentacene) has been found in which molecules tend to self-organize. As a result, the mobility has been pushed up to 3 cm2/volts. Scientist working on pentacene estimate a number close to 50 cm2/volts as the limit of achievable mobility for this special polymer.

These expectations are not just wishful thinking of some optimistic scientists. In fact, even now there are some significant outcomes of plastic technology.

Current developments

John Rogers and coworkers from Bell Labs (Lucent Technologies) have patterned 256 polymer transistors on the back-plane of a flexible optical display. Richard Friend and coworkers from University of Cambridge have produced thin film transistor circuits using a high-resolution inkjet printing. Dago de Leeuw and colleagues at Philips Research Laboratories in Eindhoven, The Netherlands, have developed a new technique called photochemical patterning. In photochemical patterning, a light sensitive-polymer is exposed to ultraviolet light through a mask shaped in the form of the desired circuit. The ultraviolet light changes the polymer from a conducting state to a non-conducting state. In this process, the polymer’s resistance can increase as much as 11 orders of magnitude (100000000000). The advantage of this technique over the patterning techniques used for silicon is that it does not need any vacuum and can be used on flexible substrates. The problems with photochemical patterning are that it is not significantly cheaper than photolithography and etching used for silicon, and it can be used only for light-sensitive polymers. Different research groups have developed various techniques that have pros and cons compared to photochemical patterning. However, many of the techniques cannot print features that are small enough for electronic circuits. The critical length is the distance between the transistor’s source and drain, typically 0.01 mm. This is the distance that the field-induced charges have to travel. As the drive current and switching speed of the device depend on this distance, having too large of a distance reduces the capabilities of the device. Another technique that pursues quite a different approach is microcontact printing. Developed by the Bell Labs group, microcontact printing with rubber-like stamps can make small enough features. Scientists have used this technique to make a flexible display in which a transistor controls each pixel. The key point in developing this technique was using gold pads, instead of a polymeric material, to deposit the transistor’s source and drain. Even though this device is not completely plastic, it is a step toward that goal. When a special kind of ink was applied to a thin film of gold, it formed some sort of self-assembled layer on the gold, which then produced well-defined patterns and sharp edges. This provided the required resolution to make small enough features necessary for an electronic device having a reasonable speed. These two techniques show two important aspects of the problem. In photochemical printing, we have a device that is completely plastic and so has the important advantage of flexibility. However, it is not as cheap as it could be and does not have the required resolution. In the second technique, the outcome is not a 100 percent plastic device, so it is not as flexible as a purely plastic circuit. However, it can be manufactured very cheaply and has a better resolution (and thus a higher switching speed).

Conclusion

Many other approaches are being employed to develop this new and exciting technology. If plastic electronics does become standard for at least some applications, it probably will be a hybrid of these different techniques. If the optimistic group of scientists working on plastic electronics prove to be right, one day we might see TV screens curling around the walls of our rooms and even reloadable electronic newspapers that can be folded and carried like regular newspapers. Who knows what new inventions will come with this new technology?

References

• Garnier, F., (et al). Science 265 (1994): 1684-86.
• Gelinck, G., T. Geuns, and D. de Leuw. Applied Physics Letters 77 (2000): 406-8.
• Levi, Barbara G. ‘New Printing Technologies Raise Hopes for Cheap Plastic Electronics.’ Physics Today (February 2001). Online at: www.physicstoday.org/pt/vol-54/iss-2/p20.html.
• Nobel Focus: Electricity through Plastic.’ Physical Review Focus (24 October 2000). Online at: http://focus.aps.org/v6/st18.html.
• Scott, Campbell. ‘Electronics Put It on Plastics.’ Physics in Action. (October 1998). Online at: www.physicsweb.org/article/world/11/30/3/1.
• Voss, David. ‘Cheap and Cheerful Circuits.’ Nature 407 (28 September 2000).

Recently, the population of the world has grown enormously, as has consumption of goods and services, and this has meant an enormous increase in the volume of waste. Many scientific studies have been undertaken to find solutions to the ‘garbage problem’, which is, of course, also a pollution problem. Some studies showed that for plastics to be broken down completely and absorbed naturally could take as much as 400 years. Environmentally sensitive consumers therefore turned to using paper instead of plastics. But were they right to have done so? Or was it just a bit o f clever advertising by paper manufacturers?

Paper or plastic?

Paper manufacturers initiated many ‘anti-plastic’ campaigns. David Jacobson (1990) notes that they had lost about 60% of their grocery bag market to plastics by the 1980s. Paper once 20% more expensive than plastics was by then double the cost. But cost was not the only factor in consumer preferences. Technological advances made plastics thinner and lighter, requiring less storage space and reducing delivery costs. Consumers increasingly preferred lightweight plastic bags with moulded handles, and stores were happy to push the cheaper bags. Stone Container Corporation (which claims about 40% of the paper grocery market and 20% of the total grocery bag market) launched a vigorous campaign to raise consumer demand for paper grocery bags in the test markets of Jacksonville, Florida, and Hartford, Connecticut. The 13-week campaign included full-page newspaper ads, billboard advertising and 30-second prime time TV spots. According to Jacobson, the campaign improved paper bag sales by about 3%.

Plastic manufacturers fought back quickly, arguing that paper was not environmentally better than plastic: they ‘publicized findings that nothing degrades in a landfill – even biodegradable paper bags – thus negating part of paper’s environmental claim’ (Jacobson, 1990).

According to ‘The Changing Bag Market’, a market research report published by Business Communications Co. Inc., ‘low energy costs and favourable consumer response to plastic bags could increase plastic’s market share to 56.2% by the year 2000’ (quoted in ibid.).

The battle has remained remarkably positive. Both plastic and paper manufacturers acknowledge that they want to increase sales, but both express genuine concern for the environment.

Another preliminary study, done by Bank of America’s Environmental Policies and Programs Department, indicated that ‘though plastic film requires a bit more energy to manufacture, it may be the better choice because.., made with less water and chemicals’ (Bank of America, 1996. p.1).

Degradable plastics

Unlike traditional plastics, which may last 200 to 400 years, degradable plastics may deteriorate in a matter of months (GAO, 1988, p.8).

The report of the US General Accounting Office (GAO) grants that ‘degradable plastics may thus be able to reduce the life span of litter in the landscape and at sea; they also diminish the amount of plastics accumulating in landfills. Technical uncertainties about the performance of degradable plastics, however, have stirred some questions about their ability to alleviate these problems. As a result, some experts contend that recycling and incineration …. may be more effective responses to the environmental problems posed by plastics…:

In addition to their potential environmental benefits, it must be noted that degradable plastics offer new opportunities for use with agricultural products.

The private sector, local state and federal government have promoted the use of degradable plastics. In a letter dated January 19, 1988, Senator John Glenn, Chairman of the Senate Committee on Governmental Affairs, asked the GAO to conduct a study of federal government activities in the area of degradable plastics. Subsequently, the GAO contacted officials and scientists in the federal government and private sector. They found that the US Department of Agriculture, the Department of Defense, the Department of Energy, and the National Science Foundation were together supporting 12 research and development projects directly related to degradable plastics, at a total funding level of $1.7 million in fiscal year 1988 (GAO, 1988, pp.8-13).

Recycling vs incineration of plastics

Incineration of paper or plastics is controversial: ‘… some people

object to the disposal of plastics [also paper] in waste-to- energy plants because, they say, plastics burned for energy are lost forever, but recycling allows the product to be used over and over again’ (Alexander, 1993, p. 138). Recycling is a better way of protecting the environment which has been gaining wider acceptance in recent years. Package goods titans such as Procter & Gamble and Lever Brothers, have both made commitments to use a percentage of recycled plastic resins in their detergent bottles and other consumer products. ‘Contrary to public presumptions, plastics are among the easiest materials to recycle, reports Amoco, one of two hundred companies re claiming millions of used plastic containers for conversion to paintbrush bristles, traffic signs, toys, floor tiles, wastebaskets, plastic lumber, and many other useful items…’ (ibid.)

As of 1990 about 20% of soft-drink bottles were being recycled for use in making textiles and fibres, appliance handles, etc. (Saunders, 1993, pp. 178-9). Among numerous other examples of applications for recycled plastics, McDonald’s Playlands are composed of partially shredded, worn-out tyres.

On the other side, while a number of US companies have adopted plans to buy recycled paper supplies, many have resisted instituting such policies because of concerns over cost or quality. Because of the current technology, recycled paper products can cost 50% to 60% more than new ones (Eisenhart, 1990, p.20).

For the present, then, it would appear that, contrary to common misconceptions; the use of plastics is better for the environment than the use of paper.

References

• ALEXANDER, i.E-I. (1993) In Defense of Garbage, Praeger. Westport, CT.
• BERNARD, K. & LAWLER, E.D. (1990) ‘Recycling, Yes. Buying recyclables? Well’, Business Marketing, 75(11), pp.30-2.
• EISENHART, T, (1990) ‘There’s gold in that garbage!’ Business Marketing, 75(11), pp.2O-5.
• GAO [=US General Accounting Office I (1988) Degradable Plastica: Standards, research, and development, Report to the Chairman,Committee on Govemmcntal Affairs, US Senate, Washington, DC.
• JACOBSON, 0. (1990) ‘Paper marketers aim to bag their plastics cornpetitors’, Business Marketing, 75 (11), pp.32-3.