Showing papers by "University of Calcutta published in 2012"
TL;DR: An Empirical Mode Decomposition (EMD) based ECG signal enhancement and QRS detection algorithm is proposed and a single fold processing of each signal is required unlike other conventional techniques.
229 citations
TL;DR: The antimicrobial activity of as synthesized silver nanoparticles is tested against the bacteria, Bacilli subtilis, Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa.
224 citations
TL;DR: Yoga is reported to reduce stress and anxiety, improves autonomic functions by triggering neurohormonal mechanisms by the suppression of sympathetic activity, and even, now-a-days, several reports suggested yoga is beneficial for physical health of cancer patients.
Abstract: Thousands of years ago yoga originated in India, and in present day and age, an alarming awareness was observed in health and natural remedies among people by yoga and pranayama which has been proven an effective method for improving health in addition to prevention and management of diseases. With increasing scientific research in yoga, its therapeutic aspects are also being explored. Yoga is reported to reduce stress and anxiety, improves autonomic functions by triggering neurohormonal mechanisms by the suppression of sympathetic activity, and even, now‑a‑days, several reports suggested yoga is beneficial for physical health of cancer patients. Such global recognition of yoga also testifies to India’s growing cultural influence.
210 citations
TL;DR: Modifications to protect insulin from the harsh acidic environment of the gastro-intestinal tract and the presence of proteolytic enzymes in the stomach and intestine limit the effective absorption of external insulin within the GI tract are described.
193 citations
TL;DR: A good correlation between the in vitro and in vivo experiments indicated that the biological applications employing Ag-np should be given special attention besides adapting the antimicrobial potential.
Abstract: The biocidal effect of silver nanoparticles (Ag-np) has resulted in their incorporation into consumer products. While the population exposed to Ag-np continues to increase with ever new applications, Ag-np remains a controversial research area with regard to their toxicity in biological systems. Here a genotoxic and cytotoxic approach was employed to elucidate the activity of Ag-np in vitro and in vivo. Characterization of Ag-np using scanning electron microscopy revealed a size range of 90-180nm. Cytotoxic potential of Ag-np was evaluated in human lymphocytes via cell viability assay (Trypan blue dye exclusion method, MTT and WST assay). The uptake and incorporation of Ag-np into the lymphocytes was confirmed by flow cytometry. Additionally apoptosis (AnnexinV-FITC-PI staining) and DNA strand breaks (comet assay) in human lymphocytes revealed that Ag-np at concentration 25μg/ml can cause genotoxicity. In vivo experiments on plants (Allium cepa and Nicotiana tabacum) and animal (Swiss albino male mice) showed impairment of nuclear DNA. Induction of oxidative stress was also studied. The DNA damage and chromosomal aberrations raise the concern about the safety associated with applications of the Ag-np. A single ip administration of Ag-np gave a significant (P≤0.05) increase in the frequency of aberrant cells and Tail DNA percent at concentrations 10mg/kg body weight and above. Results of comet assay in A. cepa and N. tabacum demonstrated that the genotoxic effect of Ag-np was more pronounced in root than shoot/leaf of the plants. The present study indicated a good correlation between the in vitro and in vivo experiments. Therefore the biological applications employing Ag-np should be given special attention besides adapting the antimicrobial potential.
192 citations
TL;DR: A multiresolution approach along with an adaptive thresholding is used for the detection of R-peaks and the T wave is detected in the QT segment of digitized electrocardiograph recordings.
146 citations
TL;DR: Production of gold nanoparticles by algae is more ecofriendly than purely chemical synthesis, however, the choice of algae is important: Chara zeylanica and Pithophora oedogoniana were found to be unable to produce nanoparticles.
Abstract: The cyanobacteria Phormidium valderianum, P. tenue and Microcoleus chthonoplastes and the green algae Rhizoclonium fontinale, Ulva intestinalis, Chara zeylanica and Pithophora oedogoniana were exposed to hydrogen tetrachloroaurate solution and were screened for their suitability for producing nano‐gold. All three cyanobacteria genera and two of the green algae (Rhizoclonium fontinale and Ulva intestinalis) produced gold nanoparticles intracellularly, confirmed by purple colouration of the thallus within 72 h of treatment at 20°C. Extracted nanoparticle solutions were examined by UV‐vis spectroscopy, transmission electron microscopy (TEM) and X‐ray diffractometry (XRD). XRD confirmed the reduction of Au (III) to Au (0). UV‐vis spectroscopy and TEM studies indicated the production of nanoparticles having different shapes and sizes. Phormidium valderianum synthesized mostly spherical nanoparticles, along with hexagonal and triangular nanoparticles, at basic and neutral pHs (pH 9 and pH 7, respectively). Medi...
145 citations
TL;DR: The synthesized nanoparticles were used for the photocatalytic reduction of hexavalent chromium in aqueous medium under solar radiation and it was observed that the initial reduction rates varied with the difference in morphology of ZnO crystallites.
134 citations
TL;DR: In this paper, a cylindrical dielectric resonator antenna (CDRA) has been examined with a view for using it as another radiating mode with broadside radiation patterns.
Abstract: A resonant mode (HEM12δ), other than those ( HEM11δ and TM01δ) conventionally excited and used in a cylindrical dielectric resonator antenna (CDRA) has been examined with a view for using it as another radiating mode with broadside radiation patterns. Excitation of the mode, being the most challenging aspect, has been discussed and resolved by employing an innovative technique. The proposed concept has been successfully verified and experimentally demonstrated for the first time. More than 8-dBi peak gain with excellent broadside radiation has been obtained from a prototype shaped from a commercially available low-loss dielectric material with relative permittivity 10.
132 citations
TL;DR: An arsenic adsorbent comprising alumina nanoparticles dispersed in polymer matrix was developed and its removal potential studied, found to be pH dependent, and maximum removal was obtained at pH 7.2, which would make it an ideal material for removal of arsenic from drinking water.
130 citations
TL;DR: Kinetic data analysis following Michaelis-Menten treatment reveals that the catecholase activity of the complexes is influenced by the flexibility of the ligand and also by the geometry around the metal ion.
Abstract: Three double phenoxido-bridged dinuclear nickel(II) complexes, namely [Ni2(L1)2(NCS)2] (1), [Ni2(L2)2(NCS)2] (2), and [Ni2(L3)2(NCS)2] (3) have been synthesized using the reduced tridentate Schiff-base ligands 2-[1-(3-methylamino-propylamino)-ethyl]-phenol (HL1), 2-[1-(2-dimethylamino-ethylamino)-ethyl]-phenol (HL2), and 2-[1-(3-dimethylamino-propylamino)-ethyl]-phenol (HL3), respectively. The coordination compounds have been characterized by X-ray structural analyses, magnetic-susceptibility measurements, and various spectroscopic methods. In all complexes, the nickel(II) ions are penta-coordinated in a square-pyramidal environment, which is severely distorted in the case of 1 (Addison parameter τ = 0.47) and 3 (τ = 0.29), while it is almost perfect for 2 (τ = 0.03). This arrangement leads to relatively strong antiferromagnetic interactions between the Ni(II) (S = 1) metal centers as mediated by double phenoxido bridges (with J values of −23.32 (1), −35.45 (2), and −34.02 (3) cm3 K mol–1, in the conventi...
TL;DR: In this paper, two rice cultivars, BR29 and IR68899B, were used to compare the yield losses due to dehydration and salt loading stresses, and showed that enhanced tolerance to dehydration was observed in the plants transformed with DREB1A isolated from Arabidopsis while DrekB1B was found to be more effective for salt tolerance.
Abstract: 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.
TL;DR: A diphenoxido-bridged dinuclear copper(II) complex, [Cu(2)L(2)(ClO(4))(2)] (1), has been synthesized using a tridentate reduced Schiff base ligand, 2-[[2-(diethylamino)ethylamino]methyl]phenol (HL).
Abstract: A diphenoxido-bridged dinuclear copper(II) complex, [Cu2L2(ClO4)2] (1), has been synthesized using a tridentate reduced Schiff base ligand, 2-[[2-(diethylamino)ethylamino]methyl]phenol (HL). The addition of triethylamine to the methanolic solution of this complex produced a novel triple bridged (double phenoxido and single hydroxido) dinuclear copper(II) complex, [Cu2L2(OH)]ClO4 (2). Both complexes 1 and 2 were characterized by X-ray structural analyses, variable-temperature magnetic susceptibility measurements, and spectroscopic methods. In 1, the two phenoxido bridges are equatorial–equatorial and the species shows strong antiferromagnetic coupling with J = −615.6(6.1) cm–1. The inclusion of the equatorial–equatorial hydroxido bridge in 2 changes the Cu···Cu distance from 3.018 A (avg.) to 2.798 A (avg.), the positions of the phenoxido bridges to axial–equatorial, and the magnetic coupling to ferromagnetic with J = 50.1(1.4) cm–1. Using 3,5-di-tert-butylcatechol as the substrate, the catecholase activit...
TL;DR: The proposed algorithms were extensively applied on all the 322 mammogram images in MIAS database resulting in complete pectoral muscle suppression in most of the images.
TL;DR: Compared with IL-6 neutralization, more pronounced down-regulation of collagen synthesis and regression ofhypertrophy was observed with STAT3 inhibition, suggesting that STAT3 is the major downstream signaling molecule and a potential therapeutic target for cardiac hypertrophy.
TL;DR: A green and highly efficient protocol has been developed for the synthesis of 4H-pyran scaffolds installing a one-pot three-component coupling reaction of an aldehyde, malononitrile, and a 1,3-diketo compound using nano structured ZnO as the catalyst in aqueous alcoholic medium.
TL;DR: The structural, optical and magnetic properties of the Zn1−xMnxO (0, <,x,<,0.05) thin films synthesized by solgel technique have been analyzed in the light of modification of the electronic structure and disorder developed in the samples due to Mn doping as mentioned in this paper.
TL;DR: In this article, the analog performance of a double-gate n-type tunnel field effect transistor (n-TFET) with a relatively small body thickness (10 nm) was investigated.
Abstract: In this paper, the analog performance is reported for the first time for a double-gate (DG) n-type tunnel field-effect transistor (n-TFET) with a relatively small body thickness (10 nm), which shows good drain current saturation. The device parameters for analog applications, such as transconductance gm, transconductance-to-drive current ratio gm/ID, drain resistance RO, intrinsic gain, and unity-gain cutoff frequency fT, are studied for DG n-TFET, with the help of a device simulator, and compared with that for a similar DG n-MOSFET. Although gm is lower, gm/ID is found to be higher in TFET, except for small values of the gate overdrive voltage, indicating that a TFET can produce higher gain at the same power level than a MOSFET. An extremely high RO and, hence, a high intrinsic gain are also observed for a TFET as compared with that for a MOSFET. A complementary TFET amplifier is found to have more than one order of magnitude higher voltage gain than its MOS counterpart. It is also demonstrated that the drain resistance and, hence, the device gain significantly degrade for increasing body thickness of a TFET.
TL;DR: Results from exact calculation of a discrete version and numerical simulations of the continuous version of the model indicate the existence of a universal continuous phase transition at p=pc below which a consensus is reached.
Abstract: We propose a model of continuous opinion dynamics, where mutual interactions can be both positive and negative. Different types of distributions for the interactions, all characterized by a single parameter p denoting the fraction of negative interactions, are considered. Results from exact calculation of a discrete version and numerical simulations of the continuous version of the model indicate the existence of a universal continuous phase transition at p = p c below which a consensus is reached. Although the order–disorder transition is analogous to a ferromagnetic–paramagnetic phase transition with comparable critical exponents, the model is characterized by some distinctive features relevant to a social system.
TL;DR: It may be proposed that the radical pathway is probably responsible for conversion of 3, 5-DTBC to 3,5-DTBQ promoted by complexes of redox-innocent Zn(II) ion.
Abstract: Four dinuclear and three mononuclear ZnII complexes of phenol-based compartmental ligands (HL1–HL7) have been synthesized with the aim to investigate the viability of a radical pathway in catecholase activity. The complexes have been characterized by routine physicochemical studies as well as X-ray single-crystal structure analysis: [Zn2(H2L1)(OH)(H2O)(NO3)](NO3)3 (1), [Zn2L2Cl3] (2), [Zn2L3Cl3] (3), [Zn2(L4)2(CH3COO)2] (4), [Zn(HL5)Cl2] (5), [Zn(HL6)Cl2] (6), and [Zn(HL7)Cl2] (7) [L1–L3 and L5–L7 = 2,6-bis(R-iminomethyl)-4-methylphenolato, where R= N-ethylpiperazine for L1, R = 2-(N-ethyl)pyridine for L2, R = N-ethylpyrrolidine for L3, R = N-methylbenzene for L5, R = 2-(N-methyl)thiophene for L6, R = 2-(N-ethyl)thiophene for L7, and L4 = 2-formyl-4-methyl-6-N-methylbenzene-iminomethyl-phenolato]. Catecholase-like activity of the complexes has been investigated in methanol medium by UV–vis spectrophotometric study using 3,5-di-tert-butylcatechol as model substrate. All complexes are highly active in catal...
TL;DR: A proposed mechanistic principal might serve as a set of design rule for the synthesis of nanostructures with desired architecture and can be amenable for the large scale commercial production and technical applications.
Abstract: The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials (AuNPs) using microorganisms is gaining importance in the field of nanotechnology. In the present study, AuNPs have been synthesized by bio-reduction of chloroauric acid (HAuCl4) using the fungal culture filtrate (FCF) of Alternaria alternata. The synthesis of the AuNPs was monitored by UV–visible spectroscopy. The particles thereby obtained were characterized by UV, dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Energy-dispersive X-ray study revealed the presence of gold in the nanoparticles. Fourier transform infrared spectroscopy confirmed the presence of a protein shell outside the nanoparticles which in turn also support their stabilization. Treatment of the fungal culture filtrate with aqueous Au+ ions produced AuNPs with an average particle size of 12 ± 5 nm. This proposed mechanistic principal might serve as a set of design rule for the synthesis of nanostructures with desired architecture and can be amenable for the large scale commercial production and technical applications.
TL;DR: The study suggested that smoking is associated with altered semen quality, endocrine hormonal status, and number of CAG repeats in the AR gene.
Abstract: This study was conducted as part of an epidemiological survey of 126 nonsmokers and 178 smokers, showing primary infertility residing around Kolkata region of Eastern India. Their lifestyle history including smoking habits along with semen and blood were collected. The study examined the association of cigarette smoking with the risk of infertility, by determining the semen quality, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone levels, and androgen receptor (AR)-CAG repeat length in a group of smokers compared with a control group (non smokers). Based on conventional WHO criteria, lower sperm motility (P < 0.001) and increased sperm morphological defects (P < 0.0001) were associated with smoking habits. Binary logistic regression analysis for the effect of smoking status on sperm DNA integrity demonstrated significant positive correlation (p = 0.006). Serum FSH and LH levels were higher for smokers compared with non-smokers while the testosterone level decreased significantly ...
TL;DR: The biosorbents can be utilized as low-cost sorbents for the removal of Pb(II) ions from wastewater and indicated that the adsorption processes were endothermic.
Abstract: Purpose
The purpose of the research is to investigate the applicability of the low-cost natural biosorbents for the removal of Pb(II) ions from aqueous solution and effluent from battery industry.
TL;DR: This porous compound shows remarkable selectivity for adsorption of CO( 2) over N(2) that may be correlated with the effect of window flexibility of the pore to the corresponding adsorbate molecules.
Abstract: A multifunctional porous metal organic framework based on mixed-valence hexa-nuclear [Mn(III)(2)Mn(II)(4)O(2)(pyz)(2)(C(6)H(5)CH(2)COO)(10)] (pyz = pyrazine) units has been synthesized. The complex has been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis, and variable-temperature magnetic measurements. The structural analysis reveals that the bidentate pyz molecules connect each [Mn(6)] unit to its four [Mn(6)] neighbors through the peripheral Mn(II) centers, giving rise to a three-dimensional (3D) distorted diamond-like porous framework. Variable-temperature (2-300 K) magnetic susceptibility measurements show the presence of dominant antiferromagnetic interactions within the discrete [Mn(6)] cluster that have been fitted with a model containing three exchange constants developed for the complex (J(1) = -8.6 cm(-1), J(2) = -3.9 cm(-1), and J(3) = -100.0 cm(-1)). Using 3,5-di-tert-butyl catechol (3,5-DTBC) as the substrate, catecholase activity of the complex has been studied; the turn over number is determined to be of 2547 h(-1) in acetonitrile. This porous compound shows remarkable selectivity for adsorption of CO(2) over N(2) that may be correlated with the effect of window flexibility of the pore to the corresponding adsorbate molecules.
TL;DR: In this paper, the authors analyzed the land transformation of few islands in Indian Sunderbans using maps and satellite images in increasing order of temporal frequency between 1924 and 2008, which revealed that both the erosion and accretion processes go hand in hand.
Abstract: Climate change induced sea level rise (SLR) added with anthropogenically altered environment leads to rapid land dynamics in terms of erosion and accretion; and alteration in species diversity and productivity, more pronouncedly in sensitive ecosystems such as river deltas. Here, we tried to analyze the historical records to understand the SLR with respect to hydrological conditions, sedimentation and morphological processes. We analyzed the land transformation of few islands in Indian Sunderbans using maps and satellite images in increasing order of temporal frequency between 1924 and 2008, which revealed that both the erosion and accretion processes go hand in hand. Increase of downstream salinity due obstruction in upstream has led to decrease in transparency of water causing decrease in phytoplankton and fish, density and diversity in the central sector of Indian Sunderbans. Analysis of the above ground biomass of three dominant mangrove species (Sonneratia apetala, Avicennia alba and Excoecaria agallocha) revealed better growth in the western sector compared to the central sector. The study reveals the cumulative effect of climate change and anthropogenic disturbance on the diversity and productivity in World’s largest ecosystem; and advocates mangrove plantation and effective management of freshwater resources for conservation of the most vulnerable and sensitive ecosystem.
TL;DR: The use of arsenic-contaminated groundwater for irrigation purpose in crop fields elevates arsenic concentration in surface soil and in the plants, which can also affect the overall production of rice, and can reduce the economic growth of a country as mentioned in this paper.
Abstract: Arsenic (As) is a metalloid that poses serious environmental threats due to its behemoth toxicity and wide abundance. The use of arsenic-contaminated groundwater for irrigation purpose in crop fields elevates arsenic concentration in surface soil and in the plants. In many arsenic-affected countries, including Bangladesh and India, rice is reported to be one of the major sources of arsenic contamination. Rice is much more efficient at accumulating arsenic into the grains than other staple cereal crops. Rice is generally grown in submerged flooded condition, where arsenic bioavailability is high in soil. As arsenic species are phytotoxic, they can also affect the overall production of rice, and can reduce the economic growth of a country. Once the foodstuffs are contaminated with arsenic, this local problem can gain further significance and may become a global problem, as many food products are exported to other countries. Large-scale use of rainwater in irrigation systems, bioremediation by arsenic-resistant organisms and hyperaccumulating plants, and the aerobic cultivation of rice are some possible ways to reduce the extent of bioaccumulation in rice. Investigation on a complete food chain is urgently needed in the arsenic-contaminated zones, which should be our priority in future researches.
TL;DR: The studies indicated that the aqueous extract of Curry leaf protects the rat cardiac tissue against cadmium-induced oxidative stress possibly through its antioxidant activity.
TL;DR: In this paper, the first intracellular bioconversion of auric ion (Au3+) to gold nanorod by the cyanobacterium Nostoc ellipsosporum has been observed for the first time in laboratory condition.
Abstract: Intracellular bioconversion of auric ion (Au3+) to gold nanorod (Au0) by the cyanobacterium Nostoc ellipsosporum has been observed for the first time in laboratory condition. The nanorods were produced within the cell after exposing the healthy growing filaments to 15 mg L−1 gold (III) solution (pH 4.5) for 48 h at 20°C. The gold nanoparticles were extracted with sodium citrate solution and were subjected to UV–Visible spectroscopy. The characteristic surface-multiple plasmon bands at 560, 610, and 670 nm were observed. The nature and size of the particles were determined by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and zeta potential studies. The nanorod size ranged from 137 to 209 nm in length and 33 to 69 nm in diameter. DLS study revealed the average hydrodynamic size as 435 nm and XRD study indicated the reduction of Au3+ to Au0. Methods of extraction and preservation of gold nanorod particles have also been studied.
TL;DR: Ca priming in the media significantly reduced the Cd accumulation and considerably alleviated the adverse impact of Cd treatment by modulating the antioxidant enzyme activity, which enhanced fresh mass of plant parts as the sign of Ca-mediated normal growth in Cd-treated lentil seedlings.
Abstract: The effect of calcium (Ca) on lentil (Lens culinaris Medic.) seedlings exposed to cadmium (Cd) stress was studied by investigating plant growth and antioxidant enzyme activities. Plants were grown for 14 days in full-strength Hoagland nutrient media supplemented with Cd concentrations of 0, 10, 20, and 40 μM, and on corresponding medium supplied with 5 mM Ca(NO3)2 prior to Cd addition. Increasing Cd led to accumulation of metal and reduced the fresh weight of the shoots more strongly than that of the roots. Cd concentrations of 20 and 40 μM were selected to study its toxic effect on seedlings. Activities of superoxide dismutase, ascorbate peroxidase, catalase, dehydroascorbate reductase, and glutathione reductase decreased at much higher magnitude in the shoots than those observed in the roots under Cd exposure. Failure of antioxidant defense in scavenging of reactive oxygen species was evidenced by abnormal rise in H2O2, resulting in enhancement of lipid peroxidation and membrane electrolyte leakage as the marks of Cd-induced oxidative stress in lentil seedlings. Ca priming in the media significantly reduced the Cd accumulation and considerably alleviated the adverse impact of Cd treatment by modulating the antioxidant enzyme activity. Mitigation of Cd-induced stress by Ca application was strongly suggested by declining levels of H2O2 and consequent lowering of oxidative damage of membrane. Consequently, this enhanced fresh mass of plant parts as the sign of Ca-mediated normal growth in Cd-treated lentil seedlings.
TL;DR: The proposed method consists of three stages: sorting and thresholding of the squared double difference signal of the ECG data to locate the pproximate Q RS regions, relative magnitude comparison in the QRS regions to detect the approximate R-peaks and RR interval processing to ensure accurate detection of peaks.