Browsing by Issue Date, starting with "2006"

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Ocular manifestations and human immunodeficiency virus retinopathy in patients with acquired immunodeficiency syndrome in North India
(2006) V. Satya Suresh Attili; Vijay P. Singh; A.V. Bhaskar Reddy; Datla V. Varma; Madhukar Rai; Kumar A. Gulati; Shyam Sundar
Aim: To evaluate the spectrum of eye diseases in patients with human immunodeficiency virus, with special reference to human immunodeficiency virus retinopathy and its risk factors. Methods: All patient with human immunodeficiency virus attending the Infectious Disease Clinic at Sir Sunderlal Hospital, Institute of Medical Sciences, Banaras Hindu University, India, between January 2001 and December 2003 were enrolled. All patients underwent a thorough eye examination. Patients with acquired immunodeficiency syndrome retinopathy were analysed separately for predisposing factors. The risk factors analysed were positive C-reactive protein, low CD4 levels, associated central nervous system infections, and other eye diseases. Statistical analysis was done using Medcalc version 7.5. Results: Of 460 analysable patients, 88 patients (19%) had some eye manifestations, and 54 patients had human immunodeficiency virus retinopathy. Univariate analysis disclosed that immunosuppression (CD4 levels, <20/μL), positive C-reactive protein, associated eye lesions, and any central nervous system pathology were significant risk factors for the development of human immunodeficiency virus/acquired immunodeficiency syndrome retinopathy. Conclusions: Human immunodeficiency virus could be a risk factor for retinopathy as a significant number of patients did not have any other findings or risk factors for the development of retinopathy. However, it would be premature to draw definitive conclusions about the risk factors, as the number of patients analysed was small. © 2006 Scientific Communications International Limited.
Developmental methylation of the regulatory region of HoxB5 gene in mouse correlates with its tissue-specific expression
(2006) Manisha Sachan; Rajiva Raman
We have studied the dynamics of de novo CpG methylation in the regulatory region of one of the homeobox gene HoxB5 during mouse development by sodium bisulfite sequencing. Methylation pattern was examined at embryonic day 18.5 and adult in kidney and spleen while in the liver the same exercise has been done in 11.5 dpc, 18.5 dpc, 5 dpp and in adult. In the liver at 11.5 dpc, all the 47 contiguous sites (including a CpG island from 2035 to 2330 bp) at 5' regulatory region of HoxB5 were unmethylated. Random methylation commences from 18.5 dpc and continues in 5 dpp and in the adult. In the kidney at 18.5 dpc, 26 CpGs were examined (excluding the CpG island region) and all of them were unmethylated but the fetal spleen had at least a few sites considerably methylated. In the adult there was a low level methylation in the kidney, on the other hand, in the spleen, all the CpGs were methylated except a few sites and certain sites were totally methylated. Thus in the adult, the level of methylation was much higher than in the fetal stage. On the other hand semi-quantitative RT-PCR revealed that the extent of expression of HoxB5 was higher in embryonic stages than in the adult. Thus HoxB5 is a good paradigm to support that the developmental methylation of HoxB5 and its expression pattern show an inverse correlation. © 2006 Elsevier B.V. All rights reserved.
Meteorological factors affecting the diversity of airborne algae in an urban atmosphere
(2006) Naveen K. Sharma; Ashwani K. Rai; Surendra Singh
Aeroalgal sampling of Varanasi City, India, was done using a Tilak Rotorod sampler and exposing agarised Bold basal medium Petri plates during March 2003 to February 2005. Amongst the 34 airborne algal genera recorded, cyanobacteria dominated the aero-algal flora, followed by green algae and diatoms. The generic diversity of airborne algae as well as the constituting groups exhibited seasonal variation. The most favored period for the appearance of cyanobacteria in the air was summer, while winter favored green algae. Presence of diatoms was almost uniform throughout the year. The presence of algal particles in the air depended upon the abundance and dynamics of algal source and their release and dispersal in the atmosphere. Best model selection with Akaike information criteria indicated temperature, relative humidity, rainfall, wind velocity as the most important climatic factors determining algal diversity. These factors exert their effect both directly by influencing entrainment and dispersal of algae from the source, and indirectly by regulating the dynamics of the possible algal source (soil, water, plant body, wall and roof of the building) by supporting or inhibiting the algal growth. In a closed environment and at low altitude sampling site characteristic is also an important factor. Open area near to the countryside had maximal aero-algal diversity. © Ecography.
Letter to the editor regarding Kho, et al. [1]
(2006) Prakash; Latha V. Prabhu; Gajendra Singh
[No abstract available]
The role of water use patterns and sewage pollution in incidence of water-borne/enteric diseases along the Ganges River in Varanasi, India
(2006) Steve Hamner; Anshuman Tripathi; Rajesh Kumar Mishra; Nik Bouskill; Susan C. Broadaway; Barry H. Pyle; Timothy E. Ford
In Varanasi, India, an estimated 200 million liters daily or more of untreated human sewage is discharged into the Ganges River. River water monitoring over the past 12 years has demonstrated faecal coliform counts up to 108 MPN (most probable number) per 100 ml and biological oxygen demand levels averaging over 40 mg/l in the most polluted part of the river in Varanasi. A questionnaire-based survey was used to estimate water-borne and enteric disease incidence and study river use among resident users of the Ganges River in Varanasi. The overall rate of water-borne/enteric disease incidence, including acute gastrointestinal disease, cholera, dysentery, hepatitis-A, and typhoid, was estimated to be about 66% during the one-year period prior to the survey. Logistic regression analysis revealed significant associations between water-borne/enteric disease occurrence and the use of the river for bathing, laundry, washing eating utensils, and brushing teeth. Thirty-three cases of cholera were identified among families exposed to washing clothing or bathing in the Ganges while no cholera cases occurred in unexposed families. Other exposure factors such as lack of sewerage and toilets at residence, children defecating outdoors, poor sanitation, low income and low education levels also showed significant associations with enteric disease outcome. This study provides an estimate of water-borne/enteric disease incidence and identifies possible risk factors for residents who live by and use the Ganges River in Varanasi. © 2006 Taylor & Francis.
Force field calculations for 2-amino-5-chloro- and 2-amino-5-bromo-benzotrifluorides
(2006) R.A. Yadav; R.K. Yadav; N.P. Singh
Force field calculations have been carried out for 2-amino-5-chloro- and 2-amino-5-bromo-benzotrifluorides using the earlier (Ref. [47] of this article) reported IR and Raman spectra. As the frequencies of the corresponding modes for the C-Br and the C-Cl groups do not differ widely the two molecules are assumed to be isotopomers for the purpose of the force field calculations. The calculated and the observed frequencies match nicely for both the molecules. Consistent assignments have been proposed for the ring modes and the internal modes of the CF3 and the NH2 groups based on the potential energy distributions (PEDs), the IR and the Raman intensities and the depolarisation ratios of the Raman lines. © 2005.
Highly controlled synthesis of poly(N-vinylpyrrolidone) and its block copolymers by organostibine-mediated living radical polymerization
(2006) Biswajit Ray; Masashi Kotani; Shigeru Yamago
Poly(N-vinylpyrrolidone)s (PNVPs) with well-defined macromolecular structure were prepared by organostibine-mediated living radical polymerization. PNVPs with expected number-average molecular weight (Mn = 3000-84 000) and low polydispersity indexes (PDIs = 1.1-1.3) were formed by heating a solution of organostibine mediator and NVP in the presence of AIBN at 60°C. The polymer structure was analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass and 2H NMR spectroscopies after reduction of the organostibanyl polymer end by tributyltin deuteride. The analyses reveal that, while the addition of AIBN considerably enhances the rate of the polymerization, the effect of azobis(isobutyronitrile) (AIBN)-derived radical to the ω-end structure is negligible. The analyses also reveal the existence of "dead" dormant species due to head-to-head addition followed by the organostibanyl group transfer. However, since the probability of the head-to-head addition is small (0.02-0.10%) compared to the normal head-to-tail addition, its effect on the controllability was negligible under the current conditions. Diblock copolymers poly(styrene [St]-block-NVP), poly(methyl methacrylate [MMA]-block-NVP), and poly(NVP-block-MMA) were successfully prepared by successive addition of corresponding monomers to the organostibine macromediators. © 2006 American Chemical Society.
A shift from significance test to hypothesis test through power analysis in medical research
(2006) G. Singh
Medical research literature until recently, exhibited substantial dominance of the Fisher's significance test approach of statistical inference concentrating more on probability of type I error over Neyman-Pearson's hypothesis test considering both probability of type I and II error. Fisher's approach dichotomises results into significant or not significant results with a P value. The Neyman-Pearson's approach talks of acceptance or rejection of null hypothesis. Based on the same theory these two approaches deal with same objective and conclude in their own way. The advancement in computing techniques and availability of statistical software have resulted in increasing application of power calculations in medical research and thereby reporting the result of significance tests in the light of power of the test also. Significance test approach, when it incorporates power analysis contains the essence of hypothesis test approach. It may be safely argued that rising application of power analysis in medical research may have initiated a shift from Fisher's significance test to Neyman-Pearson's hypothesis test procedure.
Evolutionary genetics of Drosophila ananassae. I. Effect of selection on body size and inversion frequencies
(2006) J.P. Yadav; B.N. Singh
Adaptive importance of inversion polymorphism has been discussed in Drosophila species at several levels but no study has been carried out demonstrating the individual and combined effects of polymorphic inversions on the fitness of flies through bi-directional selection. Therefore, artificial bi-directional selection for thorax length in Drosophila ananassae was carried out for 10 generations. Both, Tukey test for selection difference and regression coefficients of offspring on mid-parent are highly significant. The realized heritability (h2) in males of both high and low selection lines is more or less similar but is more pronounced in low line females, which suggests the asymmetrical response. This asymmetry in selection is discussed in the light of evidence provided by the study of chromosome inversion frequencies in different selection lines at different generations of selection. Interestingly, chromosome inversion frequency changes towards homozygosity for different gene arrangements in different selection lines. Tests of correlations at G 6 and G10 among different gene arrangements as well as with mean thorax length suggest that 2L-ST gene arrangement is negatively correlated, while 3L-ST gene arrangement is positively correlated with thorax length. Furthermore, the present study shows the significant effects of 3L-ST and 2L + 3L (positive correlation) on thorax length, while 3R-ST and 2L + 3R show significant effect (negative correlation) on thorax length, which was not evident in the previous study. Present results also suggest how polymorphic inversions and their combinations affect the body size differently in different selection lines. These results suggest that thorax length in D. ananassae is under polygenic control and inversion polymorphism plays crucial role in maintaining body size by modifying genotypic frequency under various selection pressures. © 2006 The Authors.
Effect of aqueous extract of neem (Azadirachta indica) leaves on offensive and diffensive gastric mucosal factors in rats
(2006) M. Dorababu; M.C. Joshi; G. Bhawani; M. Mohan Kumar; Aditi Chaturvedi; R.K. Goel
Standardized aqueous extract of Neem (Azadirachta indica) leaves (AIE) has been reported to show both ulcer protective and ulcer healing effects in normal as well as in diabetic rats. To study the mechanism of its ulcer protective/healing actions, effects of AIE (500 mg/kg) was studied on various parameters of offensive acid-pepsin secretion in 4 hr pylorus ligation, pentagastrin (PENTA, 5 μg/kg/hr)- stimulated acid secretion and gastric mucosal proton pump activity and defensive mucin secretion including life span of gastric mucosal cells in rats. AIE was found to inhibit acid-pepsin secretion in 4 hr pylorus ligated rats. Continuous infusion of PENTA significantly increased the acid secretion after 30 to 180 min or in the total 3 hr acid secretion in rat stomach perfusate while, AIE pretreatment significantly decreased them. AIE inhibited the rat gastric mucosal proton pump activity and the effect was comparable with that of omeprazole (OMZ). Further, AIE did not show any effect on mucin secretion though it enhanced life span of mucosal cells as evidenced by a decrease in cell shedding in the gastric juice. Thus, our present data suggest that the ulcer protective activity of AIE may be due to its anti-secretary and proton pump inhibitory activity rather than on defensive mucin secretion. Further, acute as well as sub acute toxicity studies have indicated no mortality with 2.5 g/kg dose of AIE in mice and no significant alterations in body or tissues weight, food and water intake, haematological profile and various liver and kidney function tests in rats when treated for 28 days with 1 g/kg dose of AIE.
Herbaceous species composition of an age series of naturally revegetated coal mine spoils on Singrauli Coalfields, India
(2006) Arvind Singh
The herbaceous species composition of 2-, 5- and 10-year-old age series of coal mine spoils was studied at Singrauli coalfields, India. The number of species increased with increasing age of the spoil. Two- and five-year old spoils were dominated by species belonging to the families Poaceae and Fabaceae, while the 10-year-old spoil was dominated by species belonging to the families Poaceae and Asteraceae. © Indian Institute of Science.
Growth and leaf nutrient status of companion species as influenced by neighbouring species in mixed plantations raised on mine spoil
(2006) Arvind Singh
Effect of neighbouring species on growth and foliar nutrient status of companion species was studied in mixed plantation raised on coal mine spoil. The three combinations used were legume:legume,legume:non-legume and non-legume:non-legume. The neighbouring species had influenced the growth and foliar N and P status of companion species in mixed plantations. Acacia catechu had shown greater growth and foliar N and P status when grown with neighbouring legume Pongamia pinnata than when grown with another neighbouring legume Albizia lebbeck. The growth and foliar N and P status of non-legumes Gmelina arborea and Terminalia bellerica were greater when these species were grown with the legume Pongamia pinnata than when grown with non-legume. The legume Pongamia pinnata had exhibited better growth and increased N and P concentration when grown with non-legumes Gmelina arborea and Terminalia bellerica than when grown with legume Acacia catechu. Tectona grandis, on other hand side, had shown reduced growth and foliar N and P concentration, when grown with neighbouring legumes Dalbergia sissoo and Leucaena leucocephala than when grown with neighbouring non-legume Dendrocalamus strictus. The growth rates (height, diameter and volume increments) were positively related to foliar N and P concentration. © International Society for Tropical Ecology.
Econophysics and Sociophysics: Trends and Perspectives
(Wiley-VCH, 2006) Bikas K. Chakrabarti; Anirban Chakraborti; Arnab Chatterjee
Using tricks to handle coupled nonlinear dynamical many-body systems, several advancements have already been made in understanding the behavior of markets/economic/social systems and their dynamics. The book intends to provide the reader with updated reviews on such major developments in both econophysics and sociophysics, by leading experts in the respective fields. This is the first book providing a panoramic view of these developments in the last decade. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.
Author's response [5]
(2006) Rakesh K. Singh
[No abstract available]
Ultraviolet radiation stress: Molecular and physiological adaptations in trees
(Springer Netherlands, 2006) S.S. Singh; Pankaj Kumar; Ashwani K. Rai
The ozone layer acts like a giant sunshade, protecting forests and other life forms on the Earth's surface from much of the Sun's harmful ultraviolet radiation. The depletion in stratospheric ozone layer due to anthropogenically released pollutants such as CFCs during the last few decades has resulted in increased UV radiation at ground level. UV radiation (100-400 nm) consists of UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-400 nm) radiations. Out of these three, UV-B radiation has a disproportionately large photobiological effect on forest tree species. Enhanced UV radiation affects the tree species by modifying both their biological and biochemical environment. Damage may occur in a number of ways including the direct destruction of genetic material DNA at molecular level, disruption of membranes and other cell structure and generation of highly reactive chemicals known as "free radicals". It also inhibits various physiological processes including photosynthesis, nutrient assimilation, chlorophyll and protein synthesis, which results into reduced growth and development of the tree as a whole. Enhanced UV radiation especially UV-B radiation leads to several biochemical changes in the plants and synthesize secondary metabolites (condensed tannins, phenolics, flavonoids etc.) in the leaves and other parts of the plant. These secondary metabolites are synthesized as an adaptive mechanism in trees against enhanced UV radiation and have UV-absorbing properties. It reduces the insect herbivory, several viral and fungal diseases of a tree. Elevated CO2 concentration ameliorates the damaging effects of UV radiation, whereas, drought in combination to enhanced UV radiation has inhibitory effect on plant growth and development. The inhibitory effects of enhanced UV radiation on the tree growth and development are more pronounced in the trees grown at the higher altitudes and at the equator as compared to the trees grown at lower altitude and at higher latitude. Trees undergo several changes to overcome the damaging effects of increased UV radiation by expressing new genes, synthesizing UV-absorbing compounds (secondary metabolites) and reactive oxygen scavenging enzymes. These processes in combination lead to morphological changes and thereby trees are able to tolerate UV radiation stress. © 2006 Springer. All Rights Reserved.
Water resources and climate change: An Indian perspective
(2006) R.K. Mall; Akhilesh Gupta; Ranjeet Singh; R.S. Singh; L.S. Rathore
In recent times, several studies around the globe show that climatic change is likely to impact significantly upon freshwater resources availability. In India, demand for water has already increased manifold over the years due to urbanization, agriculture expansion, increasing population, rapid industrialization and economic development. At present, changes in cropping pattern and land-use pattern, over-exploitation of water storage and changes in irrigation and drainage are modifying the hydrological cycle in many climate regions and river basins of India. An assessment of the availability of water resources in the context of future national requirements and expected impacts of climate change and its variability is critical for relevant national and regional long-term development strategies and sustainable development. This article examines the potential for sustainable development of surface water and groundwater resources within the constraints imposed by climate change and future research needs in India.
Implicit elitism in genetic search
(Springer Verlag, 2006) A.K. Bhatia; S.K. Basu
We introduce a notion of implicit elitism derived from the mutation operator in genetic algorithms. Probability of mutation less than 1/l (l being the chromosome size) along with probability of crossover less than one induces implicit elitism in genetic search. It implicitly transfers a few chromosomes with above-average fitness unperturbed to the population at next generation, thus maintaining the progress of genetic search. Experiments conducted on one-max and 0/1 knapsack problems testify its efficacy. Implicit elitism in combination with traditional explicit elitism enhances the search capability of genetic algorithms. © Springer-Verlag Berlin Heidelberg 2006.
Superfield approach to nilpotent symmetries for QED from a single restriction: An alternative to the horizontality condition
(2006) R.P. Malik
We derive together the exact local, covariant, continuous and off-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for the U(1) gauge field (Aμ), the (anti-)ghost fields and the Dirac fields of the Lagrangian density of a four (3 + 1)-dimensional QED by exploiting a single restriction on the six (4, 2)-dimensional supermanifold. A set of four even spacetime coordinates x μ (μ ≤ 0, 1, 2, 3) and two odd Grassmannian variables θ and parametrize this six-dimensional supermanifold. The new gauge invariant restriction on the above supermanifold owes its origin to the (super) covariant derivatives and their intimate relations with the (super) 2-form curvatures constructed with the help of 1-form (super)gauge connections and (super) exterior derivatives . The results obtained by exploiting (i) the horizontality condition, and (ii) one of its consistent extensions, are shown to be a simple consequence of this new single restriction on the above supermanifold. Thus, our present endeavour provides an alternative to (and, in some sense, generalization of) the horizontality condition of the usual superfield formalism applied to the derivation of BRST symmetries. © 2006 IOP Publishing Ltd.
A correlation integral approach to the study of 26 January 2001 Bhuj earthquake, Gujarat, India
(2006) P.N.S. Roy; Avadh Ram
The 26 January 2001 earthquake (ML = 6.9) of Bhuj, Gujarat, India was one of the major natural calamities in recent time for intraplate regions. The spatial distribution of correlation fractal dimension and generalized fractal dimension obtained with the correlation integral approach using 3 years of events (ML ≥ 4) including fifteen foreshocks, mainshock and 155 aftershocks was divided into six consecutive windows to see its temporal variation. The results have revealed that the spatial distribution of correlation fractal dimension and generalized fractal dimension vary in an approximate oscillating pattern in the range 0.90-2. Thus, it may be concluded that the possibility of presence of asperity/barrier is the controlling factor of the level of stress/seismicity or clustering pattern of aftershocks in the region. The Dq spectrum obtained for all the six time windows show a monofractal nature and not a multifractal pattern of the events, which is in a clustered manner for the region. This finding also supports the predominance of an asperity/ barrier model for such a high energy release along the active fault for intraplate regions without heterogeneity in fractal structure or cluster within cluster. © 2005 Elsevier Ltd. All rights reserved.
Single and combined effects of cadmium and zinc on carrots: Uptake and bioaccumulation
(2006) Rajesh Kumar Sharma; Madhoolika Agrawal
The present study was conducted to evaluate the effects of different concentrations of cadmium (Cd) and zinc (Zn), singly and in combination, on uptake and bioaccumulation of Cd and Zn in Daucus carota L. (carrot) grown under natural field conditions. Carrot plants were treated with two Cd concentrations (10 and 100 μg mL-1), two Zn concentrations (100 and 300 μg mL-1), and two combined concentrations of Cd and Zn (10 + 100 and 100 + 300 μg mL-1) 15 d after seed germination. Treatments were repeated at 10 d intervals up to 90 d of plant age. A control was also kept without a Cd or Zn treatment. Uptake, total accumulation rate (TAR), bioconcentration factor (BCF), primary transport index (PTI), secondary transport index (STI), and accumulation of Cd and Zn in root, stem, and leaf were quantified. The results show that uptake, TAR, and accumulation of Cd and Zn are concentration-dependent phenomena. Highest accumulation of Cd and Zn was found in the root, followed by the stem and then leaves. The results also showed that bioaccumulation of Cd in root, stem, and leaf was greater at the low metal-application rates of Cd and Zn in combination than at the higher rate. This study further showed that interactions of Zn and Cd are dependent on the concentrations of those metals in the soil. Copyright © Taylor & Francis Group, LLC.