SCIENCE AND TECHNOLOGY

                                  SCIENCE AND TECHNOLOGY
GRAPHENE OXIDISED:

 Graphene, popularly known as the wonder material,But there's a drawback of this material too.
It has a zero band gap which makes it impossible for pure Graphene to turn OFF when used as a switch. Hence, it is important that the material is doped with some impurities. This is where the researchers have really worked. They have oxidised Graphene to make it impure, but they have done it without damaging the lattice structure of the material.
Scientists could resort to only one process called Hummer’s method for making changes in Graphene’s structural characteristics. This process was developed in 1940s. But, because of the usage of harsh acids, it tends to make the Graphene structure unusable. But this latest technique overcomes such issues. Mark C Hersam, professor of materials science and engineering at the McCormick School explains the process. Hersam said that they had exposed hot Tungsten filament to Oxygen at about 1500 degree celsius in an ultra-high vacuum chamber. Molecular oxygen is transformed into atomic oxygen when both the elements come in contact. The researchers have introduced nascent Oxygen into Graphene which oxidises it to make it homogeneous. The researchers discovered that the electronic properties of Graphene are a result of the amount of Oxygen introduced.

It is worth mentioning here that like Silicon and plastic, Graphene has a chance to function efficiently in the modern day electronics industry.

GRAPHENE NANO RIBBONS.

A new synthetic strategy toward novel linear two-dimensional graphene nanoribbons up to 12 nm has been established. The nanoribbons are characterized by MS, UV/vis, and scanning tunneling microscopy (STM). Various microscopic studies of these novel structures showed a high tendency to self-assemble.

Graphene nanoribbons (also called nano-graphene ribbons), often abbreviated GNRs.Their electronic states largely depend on the edge structures Zigzag edges provide the edge localized state with non-bonding molecular orbitals near the Fermi energy.Graphene nanoribbons with controlled edge orientation have been fabricated by Scanning Tunneling Microscope (STM) lithography. Opening of energy gaps up to 0.5 eV in a 2.5 nm wide armchair ribbon was reported. Zigzag nanoribbons are also semiconducting and present spin polarized edges. Their gap opens thanks to an unusual antiferromagnetic coupling between the magnetic moments at opposite edge carbon atoms. This gap size is inversely proportional to the ribbon width and its behavior can be traced back to the spatial distribution properties of edge-state wave functions, and the mostly local character of the exchange interaction that originates the spin polarization.

Their 2D structure, high electrical and thermal conductivity, and low noise also make GNRs a possible alternative to copper for integrated circuit interconnects. 

a) Genetic Recombinant technique:PRDM9
During mammalian meiosis, double-strand breaks are deliberately made throughout the genome and then repaired, leading to the exchange of genetic material between copies of chromosomes. How the locations of breaks are specified was largely unknown until a fortuitous confluence of statistical genetics and molecular biology uncovered the role of PRDM9, a DNA binding protein. Many properties of this protein remain mysterious, however, including how it binds to DNA, how it contributes to male infertility—both in humans, and in hybrid mice—and why, in spite of its fundamental function in meiosis, its binding domain varies extensively among humans and across mammals. We present a brief summary of what has recently been learned about PRDM9 in different fields, focusing on the puzzles yet to be resolved.

b) GUT BACTERIA may override genetic protections against diabetes:
Obesity and type 2 diabetes have risen tremendously over the last 20 years, and the causes of these epidemics are complex. In both diseases, insulin resistance manifests early due to a combination of genetic and environmental factors, with gut bacteria and the immune system playing key roles. For example, weight gain and insulin resistance are linked to a group of gut bacteria called Firmicutes, which provide a source of extra calories by breaking down polysaccharides that are otherwise indigestible in mammals.

Insulin sensitivity is also affected by immune system proteins called Toll-like receptors (TLRs) that recognize microbial compounds. When raised in germ-free environments, mice that lack TLR2 are protected against obesity-induced insulin resistance. Intriguingly, the immune system helps regulate gut bacteria, and previous work suggests that TLRs may affect insulin sensitivity by altering the composition of enteric microbes.
present compelling evidence that gut bacteria can nullify the genetic protection against insulin resistance in TLR2-deficient mice.

To investigate the relationship between gut bacteria and insulin sensitivity, the researchers raised TLR2-deficient mice under conditions that were not germ-free. In contrast to previous findings, these mice became insulin resistant within 8 weeks, and were fatter at 12 weeks. Genetic analysis of their gut bacteria revealed that the abundance of Firmicutes was three times higher than that of wild-type mice, and the researchers suggest that this explains why these TLR2-deficient mice were not protected against insulin resistance. Because the composition of enteric microbes varies with the environment and diet, mice with the same genetic background can have different gut bacteria, and presumably this was the case for the TLR2-deficient mice in previous studies.

How could gut bacteria counteract the innate insulin sensitivity of TLR2-deficient mice? Insulin resistance can be caused by bacterial cell membrane compounds called lipopolysaccharides, and several lines of evidence suggest that this is a likely mechanism for the development of insulin resistance in the TLR2-deficient mice studied. Notably, they had higher serum levels of lipopolysaccharides, and absorbed more of them after oral administration. This suggests that these mice had more permeable guts, which is supported by the finding that their intestines had less of a tight junction protein.

The link between gut microbe composition and insulin resistance was further strengthened by a number of findings. In particular, treating TLR2-deficient mice with antibiotics brought their Firmicutes down to normal levels, reduced their fat, decreased their serum lipopolysaccharides, and increased their insulin sensitivity. This suggests that changing the composition of gut microbes reversed their insulin resistance. Moreover, when gut microbes were transplanted from TLR2-deficient mice into wild-type mice with only the genus Bacillus in their guts, the latter got fatter, had higher lipopolysaccharide levels, and were less sensitive to insulin. This suggests that the Firmicutes-rich gut bacteria from these TLR2-deficient mice were enough to cause insulin resistance.

Because obesity and insulin resistance may be promoted by fatty foods in people, the researchers compared the effects of high-fat diets on TLR2-deficient and wild-type mice. The TLR2-deficient mice got much fatter and glucose tolerance tests revealed that they also developed diabetes, indicating that the high-fat diet exacerbated their insulin resistance.

By showing that changes in gut bacteria can cause insulin resistance in mice that are genetically protected against this condition, this work suggests that the composition of enteric microbes may cause obesity and diabetes in animals that are predisposed to be lean. This work also sheds light on the interplay of genetic and environmental factors that cause metabolic syndrome in people, which is characterized by obesity and insulin resistance, and increases the risks of stroke and coronary artery disease along with type 2 diabetes.
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1)      Molecular motors: A conventional electric motor has close resemblance to the molecular motors that propel flagella in a bacterium. A few well known molecular motors are KINESINS, DYNEIN, and MYOSIN.

KENISINS- are group of motor proteins. They move materials faster across nerve cell end with a velocity of 3 micro meters per second thereby causing the transmission of nerve impulses in lightening speed.

DYNEIN- cell division is aided with this protein motor.

               These natural molecular motors have immense application in bionano technology, pharmology                 and medicine. It can be a promising approach to drug system that can utilize motor transport with in human cells and mobile components for nanoscale manufacturing in adding life to nanotechnology.

2)      ACANTHAPSIS PEDESTISIS STAL: It is an important reduviid (a winged insect) predator found in Scrub jungles and agro ecosystems of India predating on insects, pests. It can be used as a Bio-control agent. It is scarce hence; mass production is carried out in labs and supplies them to farmers.

3)      MONKEY MALARIA: Researchers in Malaysia had found the occurrence of Plasmodium Knowlesi infection among the humans, which is up till now was believed to cause malaria in monkeys. The four Species of Plasmodium are- Falciparum, vivax, ovale and malariae apart from these there are 200 species of malaria.

4)      BIOSPARGING: last time bio remediation has asked in prelims. This time it is expected. Biosparging is an insitu remediation technology that uses soil micro organisms to bio degrade organic constituents in the saturated zone of water table .In this process air, water and nutrients are injected in to the saturated zone to increase biological activity of indigenous micro organisms. Biosparging can be used to reduce the concentration of petroleum constituents that are dissolved in ground water.

5)      AIR SPARGING: This is a process in which it removes constituents primarily through volatilization while biosparging promotes biodegradation airsparging promotes volatilization. Both processes are very efficient to treat the contaminated ground water.