Selective spin transport through a quantum heterostructure: Transfer matrix method

In the present work we propose that a one-dimensional quantum heterostructure composed of magnetic and non-magnetic atomic sites can be utilized as a spin filter for a wide range of applied bias voltage. A simple tight-binding framework is given to describe the conducting junction where the heterostructure is coupled to two semi-infinite one-dimensional non-magnetic electrodes. Based on transfer matrix method all the calculations are performed numerically which describe two-terminal spin dependent transmission probability along with junction current through the wire. Our detailed analysis may provide fundamental aspects of selective spin transport phenomena in one-dimensional heterostructures at nano-scale level.Comment: 12 pages, 15 figures (Accepted for Publication in: International Journal of Modern Physics B

Genetic stability developed for β-carotene synthesis in BR29 rice line using dihaploid homozygosity

Obtaining transgenic crop lines with stable levels of carotenoids is highly desirable. We addressed this issue by employing the anther culture technique to develop dihaploid lines containing genes involved in β-carotene metabolism. First, we used Agrobacterium- mediated transformation to develop primary transgenic plants containing the β-carotene biosynthetic genes, phytoene synthase (psy) and phytoene desaturase (crtl), which were engineered for expression and accumulation in the endosperm. Transgenic plants were recovered by selecting for the expression of the phosphomannose isomerase (pmi) gene. Dihaploid plants in addition to haploid and tetraploid plant were generated from anther cultures of these primary transgenic plants. In addition to anatomical features of stomata, pollen of different ploidy-plants, molecular analyses confirmed the stable integration of the genes in the anther culture-derived dihaploid plants, and the yellow color of the polished seeds indicated the accumulation of carotenoids in the endosperm. High performance liquid chromatography (HPLC) analysis of the carotenoid extract further confirmed the levels of β–carotene accumulation in the endosperms of the transgenic dihaploid rice seeds

NUTRITIONAL PROFILE, MINERAL CONTENT AND IN VITRO ANTIOXIDANT POTENCY OF CAPSICUM ANNUM L. CULTIVATED IN 24 PARGANAS [SOUTH], WEST BENGAL, INDIA

Objective: Capsicum annum L. is a well-known spice and has long been used in Chinese traditional medicine for the treatment of various ailments. So, the present study was aimed to analyse its nutritional profile and free radical scavenging activity.Methods: The green Capsicum annum L. cultivated in 24 Parganas [South], West Bengal, were studied for the quantitative analysis of proximate composition, mineral and vitamin content. Aqueous and hydroethanolic extracts were screened on a comparative basis for the presence of in vitro antioxidant potential including the total phenol and flavonoid content, along with ferric reducing power, and 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl and superoxide radical scavenging activity.Results: The sample was found to contain 89.89% total carbohydrate, 13.48% soluble carbohydrate, 7.95% crude protein, 4.80% fat, 12.9% fibre, 95.42% moisture and 5.12% ash. Besides, the vegetable was also found to be abundant in vitamins and minerals like, sodium (24.4), iron (4.834), zinc (1.632), magnesium (92.612), manganese (0.88), calcium (19.562), copper (1.11), cobalt (0.02), chromium (0.016), boron (0.316), lycopene (2.4) and β-carotene (14.85) expressed in mg/100 g; and potassium (2.236), vitamin C (1.77), vitamin E (6.08), all expressed in g/100 g dry weight of the sample. The free radical scavenging activity, total phenol and flavonoid content of the aqueous extract were significantly higher than the hydroethanolic extract (p<0.05).Conclusion: It can thus be concluded that capsicum is a nutritionally rich spice and a potential source for antioxidant. The aqueous extract is more potent than the hydro-ethanolic extract in scavenging free radical.Â

Prevalence of hypertension and its associated risk factors among Kolkata-based policemen: a sociophysiological study

Background: In India, very sparse data are available on the prevalence of noncommunicable diseases such as hypertension among the police force, as a specific occupational group. Objectives: To determine the prevalence of hypertension and its associated risk factors among the policemen of a metropolitan city, Kolkata, West Bengal, India. Materials and Methods: A total of 916 men (policemen = 507, civilian = 409) were randomly selected from different regions of central Kolkata, and the age ranged from 20 to 60 years. Blood pressure, anthropometric parameters, lifestyle pattern, and family history of hypertension were recorded. All statistical computations were performed with SPSS, version 20.0. Results: The prevalence of hypertension [systolic blood pressure (SBP) X 140 mm Hg, diastolic blood pressure X 90 mm Hg, or use of antihypertensive drugs] was observed among 32.5% of policemen, which was significantly higher when compared with the civilians (P o 0.01). Behavioral habits and obesity indices were also higher among the policemen (P o 0.05). Regression analysis identified age, body mass index (BMI), SBP, history of parental hypertension, and consumption of smokeless tobacco as the risk factors of hypertension. As obtained from receiver-operating characteristics analysis, the suggested cutoff values for BMI were 23.64 (kg/m2), for age 47.53 year, and for SBP 135 mm Hg. Conclusion: The findings revealed that notable numbers of Kolkata-based policemen are hypertensive than civilians and lifestyle modification along with healthcare strategies must be planned for this special population

PROTECTIVE ROLE OF CRUDE EXTRACT OF AMORPHOPHALLUS CAMPANULATUS AGAINST ETHANOL-INDUCED OXIDATIVE RENAL DAMAGE

  Objective: The current study investigates the nephroprotective effect of Amorphophallus campanulatus against chronic alcohol-induced oxidative stress and tissue damage.Methods: The rats were simultaneously supplemented with ethanolic extract of A. campanulatus along with ethanol (40% w/v)2 g/kg body weight/day for 30 days to evaluate the nephroprotective effect against alcohol toxicity. Renal antioxidant enzymes, serum urea, creatinine, and pro-inflammatory cytokines were assayed biochemically. Histomorphological and histochemical alterations were detected by Hematoxylin and Eosin, periodic acid Schiff, and Feulgen and Picrosirius stain, respectively. The degree of apoptotic cell death was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay technique.Results: Serum urea, creatinine, pro-inflammatory cytokines, tissue TBARS, and activity of glutathione metabolizing enzymes were significantly (p<0.01) elevated, whereas cytosolic and mitochondrial superoxide dismutase, catalase, and levels of reduced glutathione were significantly (p<0.001) decreased in the EtOH group compared to control. However, ethanolic extract of A. campanulatus (ACE) supplementation to the EtOH rats reversed these effects to normal levels. Furthermore, degenerative changes in renal cells with alcohol treatment were minimized to nearness in architecture by ACE supplementation. Glycogen and deoxyribonucleic acid depletion, excess fibrosis due to collagen deposition, and increased apoptotic cell number were also restricted by ACE supplementation, with the higher dose being more promising.Conclusion: Thus ethanol-induced nephrotoxicity was attenuated by ACE treatment by the antioxidative and antiapoptotic property of the extract. Such effects of the extract may be due to the probable presence of different bioactive components in the tuber. Hence, it can be used as a regular nutrient or therapeutic agent to protect the renal cells

Overexpression of Arabidopsis and rice stress genes’ inducible transcription factor confers drought and salinity tolerance to rice

Rice yield is greatly affected by environmental stresses such as drought and salinity. In response to the challenge of producing rice plants tolerant to these stresses, we introduced cDNA encoding the transcription factors DREB1A and DREB1B under the control of the stress inducible rd29 promoter. Two different indica rice cultivars were used, BR29, an improved commercially cultivated variety from Bangladesh and IR68899B, an IRRI bred maintainer line for hybrid rice. Agrobacterium mediated transformation of BR29 was done independently with DREB1A isolated from rice and Arabidopsis and DREB1B isolated from rice, whereas biolistic transformation was done with rice- DREB1B in the case of IR68899B. Initial genetic integration was confirmed by PCR and Southern blot analysis. Salinity tolerance was assayed in very young seedlings. Drought stress tests were found to be more reliable when they were carried out at the pre-flowering booting stage. RNA gel blot analysis as well as quantitative PCR analysis was performed to estimate the transcription level under stressed and unstressed conditions. Agronomic performance studies were done with stressed and unstressed plants to compare the yield losses due to dehydration and salt loading stresses. Noticeably enhanced tolerance to dehydration was observed in the plants transformed with DREB1A isolated from Arabidopsis while DREB1B was found to be more effective for salt tolerance

A Vector Error Correction Model Approach to Investigate the Causal Relationship among Energy Consumption, Real GDP, and Industry Value Added of Bangladesh

The paper focuses on investigating the casual relationship among Energy Consumption, Real GDP, and Industry Value Added of Bangladesh using the World Bank Development Indicators data set. The Granger causality approach has been applied to identify the short-run causality direction for all possible pairs of dynamic variables of the study. Results from the approach indicate the unidirectional short run causal relationship from Real GDP to Energy Consumption, while another unidirectional short-run causality has been found from Industry Value Added to Real GDP. The concept of cointegration and Vector Error Correction Model (VECM) are employed to find the long-run relationships among the variables. Our results show the existence of long run relationship between each pair of variables. Furthermore, the Variance Decomposition (VDC) techniques and Impulse Response Function (IRF) was also used to measure the extent/degree of dynamic properties of the variables. Bangladesh has an emerging economy with limited energy resources. Here, the evidence from our study would help policymakers in setting the appropriate energy consumption policies that will enhance and sustain economic growth for the welfare/development of this country

Magnetic Quantum Wire as a Spin Filter: An Exact Study

We propose that a magnetic quantum wire composed of magnetic and non-magnetic atomic sites can be used as a spin filter for a wide range of applied bias voltage. We adopt a simple tight-binding Hamiltonian to describe the model where the quantum wire is attached to two semi-infinite one-dimensional non-magnetic electrodes. Based on single particle Green's function formalism all the calculations are performed numerically which describe two-terminal conductance and current through the wire. Our exact results may be helpful in fabricating mesoscopic or nano-scale spin filter.Comment: 6 pages, 5 figure

The VLA-4 integrin is constitutively active in circulating chronic lymphocytic leukemia cells via BCR autonomous signaling: a novel anchor-independent mechanism exploiting soluble blood-borne ligands

in chronic lymphocytic leukemia (CLL), survival of neoplastic cells depends on microenvironmental signals at lymphoid sites where the crosstalk between the integrin VLA-4 (CD49d/CD29), expressed in ~40% of CLL, and the B-cell receptor (BCR) occurs. Here, BCR engagement inside-out activates VLA-4, thus enhancing VLA-4-mediated adhesion of CLL cells, which in turn obtain pro-survival signals from the surrounding microenvironment. We report that the BCR is also able to effectively inside-out activate the VLA-4 integrin in circulating CD49d-expressing CLL cells through an autonomous antigen-independent BCR signaling. As a consequence, circulating CLL cells exhibiting activated VLA-4 express markers of BCR pathway activation (phospho-BTK and phospho-PLC-γ2) along with higher levels of phospho-ERK and phospho-AKT indicating parallel activation of downstream pathways. Moreover, circulating CLL cells expressing activated VLA-4 bind soluble blood-borne VCAM-1 leading to increased VLA-4-dependent actin polymerization/re-organization and ERK phosphorylation. Finally, evidence is provided that ibrutinib treatment, by affecting autonomous BCR signaling, impairs the constitutive VLA-4 activation eventually decreasing soluble VCAM-1 binding and reducing downstream ERK phosphorylation by circulating CLL cells. This study describes a novel anchor-independent mechanism occurring in circulating CLL cells involving the BCR and the VLA-4 integrin, which help to unravel the peculiar biological and clinical features of CD49d+ CLL