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Researchers use graphene for converting waste to energy sources

Researchers use graphene for converting waste to energy sources

We have been concerned about the news of eruption of methane from the floor of the Arctic Ocean, however, the quantities released so far are relatively smaller than what comes out from our waste and landfills. A part of this is captured and burned for clean electricity, however, now graphene might be able to do more than that. 

Methane which is produced by anaerobic bacteria breaks down organic material in a lack of oxygen. The most suitable environment for this is the wastewater treatment plants in cities which produce more than 25 million tonnes every year. 

Methane is a stronger greenhouse gas than carbon dioxide so capturing and burning it helps from not reaching the atmosphere. We can displace fossil fuels if we are able to fully use the energy generated. Normally the biogas that is collected from waste facilities is impure so it cannot be used on a wide scale. 

Dr. Rakesh Joshi, University of New South Wales demonstrated that graphene membranes are more effective in separating methane than the systems currently in use, thus making use of waste methane viable where it is not currently present. Joshi was initially trying to use graphene for helping Sydney Water to improve the water purification process, to remove organic matter from the wastewater to make it fit for drinking. Graphene can remove 99 percent of the impurities which are not detected by other water purifying techniques. 

Graphene also helped in the filtering of biogas and it was used for powering the operations of Sydney Water. Graphene membranes are also cheaper than the other options. On burning, methane produces carbon dioxide but it is produced from wastewater by breaking down plants that draw the same amount of carbon from the atmosphere. This makes it a greenhouse neutral energy source that can balance the renewable electricity grids in low sun and wind conditions. 

The demonstration has been mainly effective in the scale of the laboratory till now. Dr. Heri Bustamante, Sydney Water said that using graphene will help in the increased capture of methane thus expanding its uses. Methane can ultimately be produced for fuelling buses in the near future.

Researchers are hopeful to ramp up the scale of its use. A near goal in the future is to capture the gases that are produced by natural wetlands and separate methane.

Google contributes large sums to climate change denying organisations

Google contributes large sums to climate change denying organizations

As per the online documents released by The Guardian, internet giant Google has made large donations to some of the most influential and powerful groups which are connected to the denial of climate change. A transparency document from Google reveals that the tech giant has contributed to several organizations, think tanks, lobby groups that deny climate change and campaign against laws to stop climate change. However, the exact figure donated to these organizations was not revealed. 

Competitive Enterprise Institute(CEI) is one of the organizations to receive donations from Google. It is a libertarian think tank that questions the alarmism surrounding global warming. It has played a role in many campaigns which doubt the consensus of the scientific community around global warming, downplaying climate change. Besides this, they have also been instrumental in convincing the American President Donald Trump to cancel the Paris agreement. 

Google has also contributed to the Cato Institute, a think tank opposing legislation related to climate change and American Conservative Union, a conservative think tank having several climate change deniers on the board. 

Google has always promoted itself as an environment-friendly company that takes climate change and global warming very seriously. Since 2007, the company has been carbon-neutral and supports several initiatives related to climate change. It has also recently made the largest corporate purchaser of renewable energy in history. 

Along with some other organizations, Google has also pledged to support the Paris Agreement abiding by the goals of the climate pact, irrespective of the decision taken by President Trump to cancel the support of the United States from the agreement. 

Responding to the accusations, a spokesperson from Google said that they are not the only major company that contributes to the organisations although disagreeing with them on their policies related to climate change. It has also made clear that collaboration or sponsoring a third-party organization does not mean in any way that it supports their entire agenda, events nor does it advocate the views of its leadership or members. Google sponsors several organizations across the entire spectrum which advocates for better policies related to technology. 

Sheldon Whitehouse, a Democratic Senator criticized Google’s action as he mentioned that corporate America should not support any trade organization or lobby group that interferes with climate. 

CEI has not answered any questions related to Google as it respects the privacy of donors. A spokesperson of the organization said that the core value of the organization is to make energy accessible to the most vulnerable sections of the society. 

Reference: The Guardian

Mouse brain tissue kept alive for several weeks in laboratory

Mouse brain tissue kept alive for several weeks in laboratory

Researchers from Japan have kept small portions of mouse brain tissue alive and viable for a period of 25 days, isolating in a culture. This has highly increased the timeline in which the isolated brain tissue can keep the functions intact extending days to weeks. This can affect the research in therapeutic drugs in a positive way. The findings have been published in the Analytical Sciences journal.

The key to success was a new technique that combines a special kind of membrane with an improved microfluidic device. Microfluidic devices use small channels for delivery of fluid into tissues and are better than the normal culture dishes specially for ex vivo tissue experiments. They can also be customized highly and mimic certain kinds of cell behaviors. They also require small volume samples thus making it easy to study the cell interactions. 

However, only a few days is not sufficient to understand how body systems react to various things. The main problem is to keep a balance. Tissues dry quickly so the system has to be kept moist along with nutrients in a wet culture medium. Too much moisture prevents cells to exchange gases which the tissue needs thus drowning it finally. This problem had to be tackled by the researchers. 

This device has a semi-permeable microfluidic channel that is surrounded by an artificial membrane and solid walls. These are made from polydimethylsiloxane, a polymer mainly used in microfluidic devices. The tissue does not sit in the bath consisting of the culture medium but instead, the fluid circulates through the channel, passing by the membrane to keep the tissues most while still maintaining the exchange of gases between cells. 

Nobutoshi Ota, a biochemist at RIKEN Center for Biosystems Dynamics Research said that the medium flow was difficult to be controlled as the microchannel between the porous membrane and PDMS walls were not normal. The team got success after repeated trials and modifications to the membrane while adjusting the flow rates of the inlet and outlet.

A small part of the brain named suprachiasmatic nucleus(SCN)  was used which is responsible for keeping the circadian and biological rhythms intact in mammals. Neuronal cells in SCN exchange information by keeping the motion of peptides and molecules between cells intact. This is ideal for studying cell interactions. 

The mice from where the SCNs were harvested had been edited genetically such that the circadian rhythm in the brain was connected to the production of a fluorescent protein indicating if everything was working properly. 

The fluorescence was active for 25 days compared to that of a normal culture dish where after 10 hours the activity control reduced by 6 percent. The experiment lasted for only 25 days since it was the cutoff time for this experiment. It could have lasted well beyond 100 days. 

Researchers believe that this can also be used for remaining organ tissues with the possibility for human organs that are grown in the laboratory. This will improve the research in organogenesis by culturing and observation which is needed for the growth of organs and tissue. 

Journal Reference: Analytical Sciences

The strange behaviour of the oobleck can now be predicted by researchers

The strange behavior of the Oobleck can now be predicted by researchers

Oobleck is a strange material that is also referred to as a non-Newtonian fluid. This weird substance behaves sometimes as a liquid and a solid the other times. It is made of water and corn-starch entertaining children for many hours. If it is punched it appears to be solid but if picked up it flows away. 

Scientists at MIT have studied the magic substance and published a 3D mathematical model that can predict when the oobleck can change from solid to a liquid and vice versa. The findings are published in the PNAS journal. 

The scientists explain that the fine particle suspensions demonstrate drastic changes in viscosity on shear which produces interesting behavior. This is captivating to both children and rheologists. In the model, researchers have introduced a 3D continuum model with the help of mixture theory coupling the particle and fluid phases. 

The term oobleck is derived from a green substance in the book Bartholomew and the Oobleck authored by Dr. Seuss. This has fascinated researchers for a long period of time as its behavior depends on the way it is interacted with. 

The size of the particles plays an important role in this ability of the non-Newtonian fluids. The particles of corn starch are a fraction of the size of a sand grain, so due to their small size, they can be influenced by the temperature and electric charges around them. On moving slowly through the oobleck, the grains repel each other however on hitting it fast, the particles touch giving the feel of a solid. According to Ken Kamrin, mechanical engineer, MIT although this can be created very easily the rules governing it are complex.

This research can be mostly considered as a recreational work, scientists think that this modeling can be used to test oobleck for several materials such as bulletproof vests. Although it is an important question if it can stop a bullet. 

Researchers had been working on a model for wet sand but had to change it to obtain the desired oobleck variables. They ran experiments to check if the model was perfect, such as squeezing it between plates and shooting a projectile to a tank having the substance. An X shaped wheel ran through the material at different speeds to help understand the behavior. The model was able to predict the change of oobleck from liquid to solid substance and vice versa as the wheel rolled back. 

Journal Reference: PNAS

 

Diamond discovered in Siberia contains another diamond inside it

Diamond discovered in Siberia contains another diamond inside it

Diamonds have been mined for a very long time. However, a diamond found in Russia might be the first of its kind. It itself is hollow with another diamond moving inside it. The diamond discovered in a mine in Siberia is named the Matryoshka Diamond after the matryoshka dolls. 

It is common to find diamonds with some type of flaw or inclusion. Most diamonds have some defect or a mineral trapped inside. Some rare materials have been obtained underneath the Earth’s surface as it had been trapped in diamonds. But according to the Russian diamond mining group ALROSA, it is very new to find a diamond within a diamond. 

The Matryoshka Diamond weighs only 0.62 carats or 0.124 grams. Its dimensions are 4.8*4.9*2.8 millimeters. The inner diamond only weighs 0.02 carats with its dimensions being only 1.9*2.1*0.6 millimeters. During the sorting process, something unusual was noticed about it and then it was sent to the Research and Development Geological Enterprise of ALROSA for further assessment. Here the diamond was subjected to several processes namely Raman and infrared spectroscopies, X-ray microtomography. 

Oleg Kovalchuk from ALROSA said that the most intriguing aspect was to understand the formation of the air space between the formation of inner and outer diamonds. Scientists have some thoughts on the processes involved in the mantle of the Earth leading to this creation. 

 According to their hypotheses, due to rapid growth, a layer of polycrystalline diamond material was formed inside the diamond was ultimately dissolved due to the mantle processes. This dissolved layer allowed a diamond to move inside another freely similar to a matryoshka nesting doll. 

The age of the diamond is estimated to be around 800 million years but this is yet to be verified. As per a Bloomberg report, it is to be sent to the Gemological Institute for America for more in-depth analysis. It is difficult to estimate the worth of it since it is so rare. 

Kovalchuk said that no such diamond has ever been obtained in the entire history of the global mining of diamonds. This is a very unique creation by the natural forces as a vacuum is not really favored by nature. Normally in such a situation, the minerals would be replaced by other substances avoiding the formation of a cavity. 

 

Creators of the lithium ion battery awarded 2019 Nobel Prize in Chemistry

Creators of the lithium-ion battery awarded the 2019 Nobel Prize in Chemistry

The 2019 Nobel Prize in Chemistry has been awarded to John B. Goodenough, M. Stanley Whittingham, Akira Yoshino by the Royal Swedish Academy for developing lithium-ion batteries. 

The Nobel committee has stressed the importance of this technology which has given us the freedom to use and enjoy portable devices such as laptops, mobile phones to even electric cars and spacecraft. The lithium-ion batteries can be easily recharged by plugging them into the mains power supply. 

To perfect such technology, there were many challenges. Lithium can release electrons easily, thus making it suitable to store and conduct electricity. However, since it is quite reactive, it has to be adjusted for making it functional inside a battery. 

A battery comprises the cathode(positive side) and anode(negative side). Dr. Whittingham was working on energy technologies that are free from fossil fuel in the 1970s, which is when he discovered a method to make cathode for a lithium battery made from titanium disulfide. It was good however the anode was made from metallic lithium making it quite explosive to work with. Dr. Goodenough improved on this in 1980, using cobalt oxide to prepare the cathode. This increased battery voltage. 

The anode in previous batteries was made from lithium metals making it not so safe to work with as it was highly reactive. Dr. Yoshino focused on this problem as he created an anode from petroleum coke where the carbon layers allowed the lithium ions to be present between them. Ions moved across batteries as electrons moved in the circuits thereby powering the devices. This whole process is reversible hence this can be repeated many times. So the battery can be charged as many times as possible before it started deteriorating. The first lithium-ion battery that was commercially viable was created by Yoshino in 1985.  

Dr. Goodenough is now the oldest person to win a Nobel Prize at 97 years of age as he surpassed Dr. Arthur Ashkin who won the Nobel Prize for Physics last year. Yoshino mentioned during the announcement of the award that the prime motivation for continuing the research was simply their curiosity. 

Only five women have been awarded the Nobel Prize in Chemistry out of 203 Chemistry Nobel Laureates since 1901. 89 of these recipients were awarded for carrying out work in the United States while only 60 were actually born. 

Check out the Nobel Prize winners from the field of Medicine and their discovery.

For the first time, meat has been grown in space

For the first time, meat has been grown in space

Technology has changed almost every aspect of our lives and now it is also influencing the way astronauts eat food. The first astronauts took their meals from tubes similar to the kinds of toothpaste, however, now the astronauts can have fruits and ice cream with a seasoning of liquid pepper and salt on their meals. Although there are restrictions to food, for example, any food leaving crumbs are considered dangerous as these particles can clog the electrical systems or air filters of the spacecraft. 

The foods also need to last for longer time periods if the resupply missions go wrong somehow. As a result, tech companies are trying new techniques to grow food in the spacecraft itself. Aleph Farms, an Israeli food-startup oversaw meat growth in space for the first time by using a 3D printer. It is not a fully new experiment as the company has cooked lab-grown steaks from December 2018 suggesting meat growth in different kinds of environment. 

Aleph Farms extracts cells from a cow by using biopsy which is then kept in a broth of nutrients. It simulates the environment inside the body of a cow and then they are grown into steak pieces. The taste is not exactly the same but it resembles the flavor and texture of regular beef. 

CEO and co-founder, Didier Toubia said that they are the only company to grow fully-textured meat which has all the muscle fibers and blood vessels needed for the tissues. For growing meat in space, the company had to tweak their process a bit. The cow cells along with nutrient broth were placed in closed vials. They were loaded to the Soyuz MS-15 spacecraft in Kazakhstan. It took off for the Russian end of the International Space Station on September 25, orbiting 400 kilometers from the surface of the earth. 

On arrival at the station, the vials were inserted into a magnetic printer from 3D Bioprinting Solutions, a Russian company. Cells were replicated by the printer for producing muscle tissues. They returned to Earth without any consumption by the astronauts. It was a conceptual experiment and the company hopes to provide sources of protein in missions to deep space, moon, and Mars in the future.

In 2015, romaine lettuce was grown by astronauts in the International Space Station. NASA is creating a “space garden” for making lettuce, carrots and other fruits on Gateway, a space station proposed to orbit Moon.  

Meat printing suggests the companies can pursue this in the harsh environments where there is a scarcity of land or water. It takes almost 5200 gallons of water to produce a kilogram of steak. Cultured meat, on the other hand, uses 10 times less land and water than normal livestock agriculture. It also quicker to cook. Aleph Farms calls its meat, “minute steak” as it only takes a few minutes to cook. 

We have to find ways to produce food while conserving the natural resources as the resources for the food industry lead to 37 percent of greenhouse gas emissions worldwide. Aleph Farms said that their experiment was a response to such issues and the Americans, Russians, Israelis, and Arabs need to unite for addressing the climate and food security concerns. 

Curiosity obtains traces of salt in the last lakes of Gale Crater

Curiosity obtains traces of salt in the last lakes of Gale Crater

The lakes on Earth turn salty on drying out and the same incident happened when the Curiosity Mars climbed to identify the younger rocks. It found some of the salts which were left behind gathering insights on life could have prospered, rather than the mere survival on Mars. Gale crater was selected in part as it provides the possibility to investigate sedimentary rocks of different ages layered on top of each other. Curiosity has found periodic clay-bearing deposits containing 30-50 percent calcium sulfate by weight as reported in a Nature Geoscience paper.

All the rocks are 3.3-3.7 billion years old dating to the Hesperian period. Likewise, rich deposits have not been found in the older rocks of the crater. According to Dr. William Rapin of the California Institute of Technology and co-authors, the salts are present due to the percolation in the rocks by the waters of the bygone lakes which were very salty. Older rocks were much less salty although they were also exposed to the waters. Curiosity might detect more recent examples even though the younger ones were never touched by water.

Like a desert lake on Earth, the waters of the Gale crater evaporated, leaving a saltier residue, but it was an intermittent process on Mars that lasted 400 million years. The rocks have been subjected to forces of weathering over this vast time period even without water, and the calcium sulfate-enhanced portions are more resistant to erosion, producing mini versions of the formations in places such as Monument Valley, where harder rocks extend above the terrain.

Curiosity found a 10-meter (33-feet) slope containing 26-36 percent magnesium sulfate, in the 150 meters (500 feet) of calcium sulfate-enriched layers. Researchers believe that before the deposition of more soluble salts, it precipitated out first.

The paper mentions that their outcomes do not compromise the life search in the Gale crater. Terrestrial magnesium sulfate-rich and hypersaline lakes are known to sustain halotolerant biota while the preservation of biosignatures may be supported by crystallization of sulfate salts.

The occasional bursts of salty water are observed even today hence it is not unique to Gale crater in having such salts. As the planet dried, sulfate deposits have been identified by Martian orbiters across several places on Mars and it is the first instance where a rover has been operated its instruments over these samples. The periodic bursts of sulfate salts found by Curiosity showed Gale crater had many rounds of drying with several wet periods rather than one single great drought.

Journal Reference: Nature Geoscience

Researchers fabricate all-perovskite tandem solar cells with improved efficiency

Researchers fabricate all-perovskite tandem solar cells with improved efficiency

A kind of solar cell having an important perovskite structured element known as Perovskite tandem solar cells (PSCs) has been fabricated by a group of scientists from Nanjing University, China and the University of Toronto, Canada. Hairen Tan, the lead researcher told that instead of making single-junction perovskite solar cells, the primary idea was to make more efficient all-perovskite tandem solar cells. The findings are reported in Nature Energy journal.

Perovskites are a group of minerals having the same crystal structure as perovskite which is yellow, black or brown mineral comprising mostly of calcium titanate. Many researchers over the past few years have been attempting to build solar cells using this material, either wide-bandgap (~1.8 eV) or narrow-bandgap (~1.2 eV) perovskites.

Merging wide and narrow bandgap perovskites together could enhance power conversion efficiency (PCEs) than that achieved by single-junction cells without any increase in fabrication costs. Scientists need to find a method to strengthen the efficiency of individual subcells, while also integrating the wide and narrow-bandgap cells synergistically for building this type of cell.

Tan said that low efficiencies (PCE~18-20 percent) and low short-circuit current densities (Jsc~28-30 mA/cm2) have been demonstrated by the mixed Pb-Sn narrow-bandgap perovskite solar cells which fall under their capacity, and under the performance of the best Pb-based single-junction perovskite cells. One of their vital components, Sn2+, readily oxidizes into Sn4+ is responsible for the weak performance in narrow-bandgap perovskite solar cells. Tan and his team wanted to determine solutions that could overcome the high trap densities and short carrier diffusion lengths exhibited by the resultant cells.

He also added that their main purpose is to extend the diffusion of narrow-bandgap perovskite solar cells thus to achieve better-performed tandem solar cells. Also, they took a perspective to stop the oxidation of Sn2+ to Sn4+ in the precursor solution to enhance charge carrier diffusion length and whose inclusion in the mixed Pb-Sn perovskites causes Sn vacancies. A new chemical method was used by Tan’s team that is based on a comproportionation reaction and leads to significant improvements in the charge carrier diffusion lengths of mixed Pb-Sn narrow-bandgap perovskites. This could eventually increase the performance of PSCs.

The team obtained an extraordinary 3 μm diffusion length that allows performance-record-breaking Pb-Sn cells and all-perovskite tandem cells unlike the earlier intended method characterized by sub-micrometer diffusion lengths, that can reduce the efficiency of the cell. He also explained that a tin-reduced precursor solution was developed to obtain this by restoring the Sn4+ (an oxidization product of Sn2+) back to Sn2+ through comproportionation reaction in the precursor solution.

The major challenge for the advancement of solar cells with a perovskite element is the oxidation of tin-containing perovskites as it adversely affects their efficiency and hampers their utilities. A substitute path for fabricating tandem solar cells using tin-containing narrow-bandgap perovskite is given by the new chemical method introduced by Tan and his co-workers making cells more stable and efficient.

Tan added that the electronic quality of tin-containing perovskites is comparable to that of lead halide perovskites that have shown efficiency similar to crystalline silicon cells. This approach will eventually provide them a way to very inexpensive and highly efficient solar devices.

The performance of monolithic all-perovskite tandem cells was tested using the chemical approach after fabrication. Remarkable independently approved PCEs of 24.8 percent for small-area devices (0.049 cm2) and 22.1 percent for large-area devices (1.05 cm2) was obtained by their cells. Additionally, after functioning for over 400 hours at their highest power point under full one sun illumination, the cells retained 90 percent of their performance. The method introduced by this team of scientists could lead to the development of more efficient and cost-effective solar-powered devices in the future.

Tan said that they are now planning to further enhance the power conversion efficiency of all-perovskite tandem solar cells above 28 percent. Minimizing the photovoltage loss in the wide-bandgap perovskite solar cell will be the primary feasible method to attain this while minimizing the optical losses in the tunneling recombination junction is another possibility.

Journal Reference: Nature Energy

Researchers awarded the Nobel Prize in Medicine for their discovery of cells adapting to low oxygen

Researchers awarded the Nobel Prize in Medicine for their discovery of cells adapting to low oxygen

The Nobel Assembly has awarded the 2019 Nobel Prize in Physiology or Medicine to William Kaelin, Sir Peter Ratcliffe, and Gregg Semenza for their discoveries of the ways in which cells sense and adapt to the availability of oxygen.

The molecular switch that helps our cells to adjust to lowering oxygen levels was discovered by the three researchers. This is necessary because it offers a hypoxic reaction when the oxygen levels change i.e. the change when altitude changes, when exercising or when getting a cut.

There are various ways by which our body handles this such as forming new blood vessels, increase of blood cell production, cells adapting to certain metabolic changes. An example of the latter situation is the production of lactic acid in muscle cells during heavy exercise. The energy captured in food is released by the cells using oxygen in a reaction called aerobic respiration. Cells can also perform anaerobic respiration to avoid using oxygen but this is not sustainable as well as inefficient in the long term for humans. The three Nobel laureates and their colleagues discovered this ability to switch from one mode to the other.

It is known that the increase in the erythropoietin hormone (EPO) is produced by the kidneys in low-oxygen conditions and in anemic people. Semenza, working at Johns Hopkins University demonstrated that the increase in EPO which stimulates the production of red blood cells is stimulated by a specific gene known as hypoxia response element or HRE.

HIF-1α is one of the proteins produced by the gene found to be oxygen sensitive which disappears in the abundance of oxygen. The cells were more likely to show symptoms of hypoxia which lack the von Hippel-Lindau gene (connected to cancer). This was discovered by William Kaelin and his team from the Dana-Farber Cancer Institute.

A relation between VHL and HIF-1α was created by Ratcliffe and his group from Oxford University and the Francis Crick Institute. They figured out the molecular details of the working of these mechanisms and also that the protein cannot be destroyed without the gene. From general metabolism and exercise response to embryo development and the functioning of the immune system, HIF-1α plays very crucial roles. It also affects conditions like anemia, cancer, strokes, and heart attacks. At present, EPO is being studied as a potential method to fight against the cancer cells by preventing them access to oxygen and nutrients.