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Topological insulators are new class of materials which are characterized by a bulk band gap like ordinary band insulators but have protected conducting states on their edges or surfaces. These states emerge due to the combination of spin-orbit coupling and time reversal symmetry. Also, these states are insensitive to scattering by non-magnetic impurities. A two-dimensional topological insulator has one dimensional edge states in which the spin-momentum locking of the electrons give rise to quantum spin Hall effect. A threedimensional topological insulator supports novel spin-polarized 2D Dirac fermions on its surface. These topological insulator materials have been theoretically predicted and experimentally observed in a variety of 2D and 3D systems, including HgTe quantum wells, BiSb alloys, and Bi2Te3, Bi2Se3 crystals. Moreover, proximity induced superconductivity in these systems can lead to a state that supports zero energy Majorana fermions, and the phase is known as topological superconductors. In this article, the basic idea of topological insulators and topological superconductors are presented along with their experimental development. 相似文献
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Putative Role of Cardio Metabolic Risk Among Poorly Controlled Asthmatics in South Indian Population
Murugaiyan Sathish Babu K. P. Sreesoorya Surendra K. Menon Subiman Saha A. R. Srinivasan S. Arul Vijaya Vani R. Reeta V. Kuzhandai Velu 《Indian journal of clinical biochemistry : IJCB》2017,32(2):225-229
Mortality and morbidity attributed to asthma remains to be the biggest nightmare worldwide. Hence, the study was aimed to compare the cardio metabolic risk factors as assessed by Body mass index (BMI), waist hip ratio (WHR), serum triacylglycerol and uric acid in well controlled and poorly controlled asthmatics and to correlate these parameters with the severity of asthma. A case control study was conducted on 90 subjects who were segregated into well controlled asthmatics (n = 30) and poorly controlled asthmatics (n = 30) who were diagnosed based on Global initiative for Asthma management guidelines and healthy volunteers (n = 30). Centrifuged fasting venous blood samples were used for biochemical analysis, pulmonary function test, BMI, and waist hip ratio (WHR) were measured. The statistical analysis was done using SPSS version 17. There was a significant increase in BMI, WHR, lipid profile, serum uric acid and decrease in forced expiratory volume (FEV1), forced vital capacity (FVC), and FEV1/FVC in poorly controlled asthmatics. There was a significant association between FEV1 and serum uric acid, BMI and Triacylgycerol in poorly controlled asthmatics. Poorly controlled asthmatics have greater risk of developing cardiometabolic problems. Serum uric acid can be used as one of the severity markers in asthma to assess cardio metabolic risk. 相似文献
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Asma Ahmed Banishree Saha Anand Patwardhan Shwetha Shivprasad Dipankar Nandi 《Resonance》2009,14(5):455-471
How do we remain healthy, for the most parts, in the midst of an environment teeming with opportunistic and infectious microbes, potential carcinogens and allergens? The fact is that our immune system, by and large, does a fine job in protecting us. It is therefore important to understand the organization of the immune network, which is broadly categorized into two groups: innate and adaptive. Cells involved in innate immunity are the first to come into contact with invading microbes, similar to the border security force, and respond rapidly but in a non-specific manner. On the other hand, the cells involved in adaptive immunity are slower to respond but act in a very specific manner. Though the primary response is slow, the secondary response is much faster and demonstrates memory. This article will focus on some important features and key players involved in the adaptive immune response. The first part deals with the humoral immune response mediated mainly by immunoglobulins produced by the B cells. The second part deals with T cells, the Major Histocompatibility Complex (MHC)-encoded molecules, and Recombination Activating Genes (RAG) responsible for generating diverse B-cell receptors (BCR) and T-cell receptors (TCR). With the advent of newer and smarter infectious agents, it is important to understand the working of the immune network as more research in this area may facilitate the development of better protective strategies. 相似文献
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A chaotic dynamical system is characterized by a positive averaged exponential separation of two neighboring trajectories over a chaotic attractor. Knowledge of the Largest Lyapunov Exponent λ1 of a dynamical system over a bounded attractor is necessary and sufficient for determining whether it is chaotic (λ1＞0) or not (λ1≤0). We intended in this work to elaborate the connection between Local Lyapunov Exponents and the Largest Lyapunov Exponent where an altemative method to calculate λ1has emerged. Finally, we investigated some characteristics of the fixed points and periodic orbits embedded within a chaotic attractor which led to the conclusion of the existence of chaotic attractors that may not embed in any fixed point or periodic orbit within it. 相似文献
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Sarama Saha Chandan Sarkar Subhash Chandra Biswas R. Karim 《Indian journal of clinical biochemistry : IJCB》2008,23(3):262-266
Abnormal lipid profile is often found in women with Polycystic Ovary Syndrome. To assess the impact of abnormal lipid profile
on atherosclerosis in young Polycystic Ovary Syndrome women, carotid intima-media thickness as judged by B-mode ultrasonography
were done in 30 young (18–35 yrs) Polycystic Ovary Syndrome women and in similarly age-matched 30 apparently healthy controls.
Compared to controls, young Polycystic Ovary Syndrome women had significantly elevated serum total cholesterol, triglyceride
and LDL-C levels and carotid intima-media thickness. HDL-C level did not differ significantly between two groups of women.
In Polycystic Ovary Syndrome women carotid intima-media thickness was positively correlated with serum total cholesterol,
triglyceride and LDL-C and negatively correlated with serum HDL-C. Our study suggests that even young Polycystic Ovary Syndrome
women are prone to atherosclerosis from early age. 相似文献
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HS Batra Ashwini Kumar TK Saha Pratibha Misra Vivek Ambade 《Indian journal of clinical biochemistry : IJCB》2015,30(2):230-233
To establish utility of single enzymatic marker for the diagnosis of acute pancreatitis. This is a cohort study. Tertiary care centre proven cases of acute pancreatitis (n = 50) admitted in surgery ward between December 2011 and May 2013 were included in the study. Serum amylase and lipase were performed along with many analytes. All relevant data including serum lab values and imaging were collected. All 50 patients included in the study had raised serum lipase, 42 patients had both amylase and lipase raised, 8 patients had amylase normal but lipase raised. In smaller hospitals where limited lab and radiological facilities are available, estimation of serum lipase will be a better choice over serum amylase in diagnosis of acute pancreatitis. 相似文献
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Rituparna Maji Sukla Nath Surajit Lahiri Mita Saha Das Ajit Ranjan Bhattacharyya Harendra Nath Das 《Indian journal of clinical biochemistry : IJCB》2014,29(2):167-173
Reference intervals (RIs) of serum thyroid stimulating hormone (TSH) and free thyroxine (fT4) were determined in 402 healthy pregnant women by enzyme-linked immunosorbent assay (ELISA) technique after partitioning them into three trimesters. The reference population was chosen from a study population of 610 pregnant females by applying strict inclusion and exclusion criteria. The assays were done using proper quality control measures. RIs were calculated from the central 95 % of the distribution of TSH and fT4 values located between the lower reference limit of 2.5 percentile and upper reference limit of 97.5 percentile value 0.90 confidence intervals for the upper and lower reference limits were also determined. The reference intervals for TSH were 0.25–3.35 μIU/ml for the first trimester; 0.78–4.96 μIU/ml for the second trimester and 0.89–4.6 μIU/ml for the third trimester. Similarly, the reference intervals for fT4 for first, second and third trimesters were 0.64–2.0, 0.53–2.12 and 0.64–1.98 ng/dl respectively. The values thus obtained varied from those provided by the kit literature. In comparison to our derived reference intervals, the reference data from kit manufacturer under-diagnosed both subclinical hypo- and hyper-thyroidism within our pregnant reference population. 相似文献
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R. Kapoor D. B. Gundpatil B. L. Somani T. K. Saha S. Bandyopadhyay P. Misra 《Indian journal of clinical biochemistry : IJCB》2014,29(2):213-220
Cancer cells generally exhibit increased glycolysis for ATP generation (the Warburg effect). Compounds that inhibit glycolysis have potential applications in cancer treatment. dl-glyceraldehyde (DLG) and 2-Deoxyglucose (2-DG) have been proven effective in the inhibition of glucose metabolism. Ehrlich ascites carcinoma (EAC) cells were injected intraperitoneally (i.p) in 10–12 weeks old Swiss albino mice, weighing between 20 and 30 g. The anticancer activity of DLG and 2-DG were determined by tumor volume, tumor weight, viable and nonviable tumor cell count, average survival time, percentage increase in life span and tumor inhibition ratio. The blood samples were obtained for biochemical analysis after 9 days of treatment to study the effect on liver, kidney and haematological parameters. Histopathological examination of liver and kidney was also performed. One-way ANOVA test and Dunnett’s test were used for comparisons of parameters in study groups. Both DLG and 2-DG individually decreased the tumor weight, tumor volume, viable tumor cell count and significantly increased the life span of treated mice, however the combination was found to be better. The biochemical parameters of liver and kidney functions and haematological parameters were restored close to control group as compared with the EAC bearing mice. Histopathological examination of liver and kidney in EAC control group showed large areas of necrosis, congestion and mononuclear cell infiltration but such changes were not observed in liver and kidney sections observed after i.p injection of DLG and 2-DG for 9 days. Improvement was much better in the group where combination of these two drugs were used. 相似文献