4,822 research outputs found

    Impact of alloy disorder on the band structure of compressively strained GaBiAs

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    The incorporation of bismuth (Bi) in GaAs results in a large reduction of the band gap energy (Eg_g) accompanied with a large increase in the spin-orbit splitting energy (SO\bigtriangleup_{SO}), leading to the condition that SO>Eg\bigtriangleup_{SO} > E_g which is anticipated to reduce so-called CHSH Auger recombination losses whereby the energy and momentum of a recombining electron-hole pair is given to a second hole which is excited into the spin-orbit band. We theoretically investigate the electronic structure of experimentally grown GaBix_xAs1x_{1-x} samples on (100) GaAs substrates by directly comparing our data with room temperature photo-modulated reflectance (PR) measurements. Our atomistic theoretical calculations, in agreement with the PR measurements, confirm that Eg_g is equal to SO\bigtriangleup_{SO} for x\textit{x} \approx 9%. We then theoretically probe the inhomogeneous broadening of the interband transition energies as a function of the alloy disorder. The broadening associated with spin-split-off transitions arises from conventional alloy effects, while the behaviour of the heavy-hole transitions can be well described using a valence band-anticrossing model. We show that for the samples containing 8.5% and 10.4% Bi the difficulty in identifying a clear light-hole-related transition energy from the measured PR data is due to the significant broadening of the host matrix light-hole states as a result of the presence of a large number of Bi resonant states in the same energy range and disorder in the alloy. We further provide quantitative estimates of the impact of supercell size and the assumed random distribution of Bi atoms on the interband transition energies in GaBix_{x}As1x_{1-x}. Our calculations support a type-I band alignment at the GaBix_xAs1x_{1-x}/GaAs interface, consistent with recent experimental findings

    Production of L-asparaginase from Natural Substrates by Escherichia coli ATCC 10536 and Comparison of Physiology Parameters

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    High demand of L-asparaginase urges the researchers to maximize the production of this enzyme with affordable cost in short period of time. Microbial fermentation is an alternative source for production of L-asparaginase enzyme due to its low cost, easy culturing techniques as well as efficient purification. Addition of substrate is in favour to maximize the production of L-asparaginase where this substrate can be in the form of natural substance or waste products. Excessive amount of waste may cause environmental pollution. Thus, by utilizating waste as substrate is beneficial because the amount of waste can be reduced greaty. This study has shown that both cooked chicken bone and Moringa oleifera seeds as food waste and natural substance respectively can be used to enhance the production of this enzyme which involves fermentatio

    AXL modulates extracellular matrix protein expression and is essential for invasion and metastasis in endometrial cancer

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    The receptor tyrosine kinase AXL promotes migration, invasion, and metastasis. Here, we evaluated the role of AXL in endometrial cancer. High immunohistochemical expression of AXL was found in 76% (63/83) of advanced-stage, and 77% (82/107) of high-grade specimens and correlated with worse survival in uterine serous cancer patients. In vitro, genetic silencing of AXL inhibited migration and invasion but had no effect on proliferation of ARK1 endometrial cancer cells. AXL-deficient cells showed significantly decreased expression of phospho-AKT as well as uPA, MMP-1, MMP-2, MMP-3, and MMP-9. In a xenograft model of human uterine serous carcinoma with AXL-deficient ARK1 cells, there was significantly less tumor burden than xenografts with control ARK1 cells. Together, these findings underscore the therapeutic potentials of AXL as a candidate target for treatment of metastatic endometrial cancer

    Treatment of Drinking Water in Economical Cost Perspective

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    It is observed that most economical way in treating the drinking water for humans with coagulation treatment cost is Rs.1.25 per litre calculated in case of open surface water but only Rs.0.15 cost for ground and water storage tanks samples, after treatment it is sure water is safe for drinking purpose. But boiling treatment of drinking water is not economical as compare to coagulation treatment because it covers the Rs. 2.5 to Rs. 1.0 it depends on nature of water quality to treat. This cost was applicable and useful for human\u27s drinking water treatment and save the medical treatment cost from suffering the painful water borne diseases such as cholera and diarrhoea. Aluminium sulphate is coagulated which economical but with low price available and we must use it for canal water treatment because 5 to 10 percent toxins are present. In case of ground water and storage water tanks, treatment we no need coagulant we just need boiling of drinking water then it is sure that toxins and other organic material vaporized and drinking water free of low toxicity and safe to health

    Dual Spikes; New Spiky String Solutions

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    We find a new class of spiky solutions for closed strings in flat, AdS3AdS5AdS_3\subset AdS_5 and R×S2(S5)R\times S^2(\subset S^5) backgrounds. In the flat case the new solutions turn out to be T-dual configurations of spiky strings found by Kruczenski hep-th/0410226. In the case of solutions living in AdSAdS, we make a semi classical analysis by taking the large angular momentum limit. The anomalous dimension for these dual spikes is similar to that for rotating and pulsating circular strings in AdS with angular momentum playing the role of the level number. This replaces the well known logarithmic dependence for spinning strings. For the dual spikes living on sphere we find that no large angular momentum limit exists.Comment: Added reference

    On Supergravity Solutions of Branes in Melvin Universes

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    We study supergravity solutions of type II branes wrapping a Melvin universe. These solutions provide the gravity description of non-commutative field theories with non-constant non-commutative parameter. Typically these theories are non-supersymmetric, though they exhibit some feature of their corresponding supersymmetric theories. An interesting feature of these non-commutative theories is that there is a critical length in the theory in which for distances larger than this length the effects of non-commutativity become important and for smaller distances these effects are negligible. Therefore we would expect to see this kind of non-commutativity in large distances which might be relevant in cosmology. We also study M5-brane wrapping on 11-dimensional Melvin universe and its descendant theories upon compactifying on a circle.Comment: 25 pages, latex file; v2: typos corrected, Refs. adde

    Managing the Quality of Chromium Sulphate during the Recycling From Tanning Waste Water

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    Quality management is a big issue during recovery and recycling process because if desired quality is not received during chromium recovery or recycling process, we may be faced another problem of recycled materials. This also seen that most important that the production processes is useless without taking specific required quality of chromium., in real way about 60%-70% of chromium salt is used as chemical interaction with the hides but 30%-40% of chemical chromium salt is wasted as the solid and liquid form. Therefore, the quality during the recovery process of the chromium sulphate from chromium wastewater that is most important step for controlling environmental pollution with some economical benefits. Recycling of chromium sulphate is possible by using chemical precipitation method for water treatment, two precipitating agents' magnesium oxide and calcium hydroxide plus alum are used for this purpose. Final findings showed that the optimum pH for efficient recovery with required quality was 8 and the Recycling of chromium sulphate was about 99(%) at pH 8 with good sludge with high settling rate. on the Base of these findings an economical production plant can be designed which are useful for quality improvement
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