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In this work, a sonication induced modified wet chemical approach is adopted to synthesize highly luminescent and water soluble cadmium telluride (CdTe) quantum dots (QDs). The morphology, size, crystal structural, and optical properties of CdTe QDs are investigated for different refluxing time (1–4 h). The refluxing time-dependent optical constants viz. band gap energy and Urbach energy of the QDs are estimated from UV–Visible absorption spectra. The optical band gap energy decreased from ~ 2.12 to 1.92 eV and the Urbach energy increased from ~ 361 to 487 meV, with the increase in refluxing time. CdTe QDs are found to be uniform in size. The average size of the QDs estimated from the High Resolution Transmission Electron Microscope image analysis is about 5.8 and 8.2 nm for refluxing times 1 and 4 h, respectively. The growth mechanism of the QDs as a function of refluxing time has also been discussed. The fluorescence spectra of the QDs, revealed emission peaks having wavelength from ~ 534 to 585 nm, under the excitation wavelength of 320 nm. The fluorescence emission peaks showed a bathochromic shift with increasing refluxing time. CdTe QDs also exhibit excitation-dependent fluorescence behaviour. Two crystalline phases of the CdTe QDs, namely hexagonal and cubic are confirmed from the High Resolution Transmission Electron Microscope images and Selected Area Electron Diffraction patterns analysis. The phase transformation from hexagonal to cubic is successfully achieved by tuning the refluxing time from 1 to 4 h.

In this work, a modified sonication induced wet chemical approach is adopted to synthesize highly luminescent and water soluble Cadmium Telluride (CdTe) quantum dots (QDs). Cadmium Chloride and Sodium Tellurite are used as the source of Cadmium and Tellurium. To limit the size of the QDs, Mercaptosuccinic acid is used as a capping agent. The refluxing time dependence on morphology, size, crystal structural, and optical properties of CdTe QDs are investigated. The refluxing time-dependent optical constants viz. band gap energy and Urbach energy of the QDs are estimated from UV-Vis absorption spectra. The fluorescence spectra of the QDs are also investigated by recording the spectra under the excitation wavelength at 320 nm. CdTe QDs are found to uniform in size. The average size of the QDs estimated from the HRTEM image analysis is about 5.8 nm and 8.2 nm for refluxing times 1 and 4 hours, respectively. The growth mechanism of the QDs as a function of refluxing time has also been discussed. Two phases of the CdTe QDs, namely hexagonal and cubic are confirmed from the HRTEM images and SAED patterns analysis. The phase transformation from hexagonal to cubic is successfully achieved by tuning the refluxing time from 1 to 4 hours.

The present study aimed at predicting the potential habitat of Western Hoolock Gibbon (Hoolock hoolock) in the upper Brahmaputra River Valley, Assam, India, and identifying priority conservation areas for the species, taking canopy cover into account. We used the maximum entropy algorithm for the prediction of the potential habitat of the gibbon using its current distribution with 19 environmental parameters as primary predictors. Spatio-temporal analyses of the habitat were carried out using satellite-based remote sensing and GIS techniques for two decades (1998–2018) along with Terra Modis Vegetation Continuous Field product to examine land use land cover (LULC), habitat fragmentation, Normalized Difference Vegetation Index (NDVI) and tree cover percentage of the study area. To identify the conservation priority area, we applied a cost-effective decision-making analysis using systematic conservation prioritization in R programming. The model predicted an area of 6025 km2 under high potential habitat, a major part of which was found to overlap with dense forest (80%), followed by moderately open forest (74%) and open forest (66%). The LULC change matrix showed a reduction of forest area in the predicted high potential habitat during the study period, while agricultural class showed an increasing trend. The fragmentation analysis indicated that the number of patches and patch density increased from 2008 to 2018 in the ‘very dense’ and ‘dense’ canopy regions of the gibbon habitat. Based on the conservation priority analysis, a 640 km2 area has been proposed to conserve a minimum of 10% of gibbon habitat. The current analysis revealed that in the upper Brahmaputra Valley most areas under dense forest and dense canopy have remained intact over the last two decades, at least within the high potential habitat zone of gibbons independent of the degree of area change in forest, agriculture and plantation.

In this paper, we introduced certain formulas for p-adic valuations of Stirling numbers of the second kind S(n, k) denoted by vp(S(n, k)) for an odd prime p and positive integers k such that n ≥ k. We have obtained the formulas, vp(S(n, n − a)) for a = 1, 2, 3 and vp(S(cpn, cpk )) for 1 ≤ c ≤ p − 1 and primality test of positive integer n. We have presented the results of vp(S(p2, kp)) for 2 ≤ k ≤ p − 1, 2 < p < 100 and a table of vp(S(p, k)). We have posed the following conjectures from our analysis: 1. Let p ≠ 7 be an odd prime and k be an even integer such that 0 < k < p − 1. Then vp(S(p2, kp))-vp(S(p2, p(k+1)) = 3 2. If k be an integer such that 1 < k < p − 1, then the p-adic valuations satisfy vp(S(p2, kp)) = 5 or 6, if k is even; 2 or 3, if k is odd for any prime p > 7. 3. For any primes p and positive integer k such that 2 ≤ k ≤ p − 1, then vp(S( p, k )) ≤ 2.

Zinc Sulphide thin films have been fabricated on glass substrate via chemical bath deposition technique using zinc acetate, thiourea as the precursor of zinc and sulfur and ammonia for varying pH. The X-Ray diffraction patterns indicate the nanocrytalline nature of the films with broadening of diffraction peaks. Effective Mass Approximation, Scherrer Method and Williamson-Hall plots have been employed for determining crystallite size. The calculated crystallite sizes correlate well with the estimated crystallite sizes from High Resolution Transmission Electron Microscopy images. The HRTEM images show clear lattice fringes of nanocrystallites overlapping each other with random orientations. The elastic properties such as lattice strain, stress and energy density of ZnS thin films have been calculated from the modified form of Williamson-Hall analysis namely Uniform Deformation Model, Uniform Stress Deformation Model, and Uniform Deformation Energy Density Model. The Scanning Electron Microscope images indicate the granular texture of synthesized ZnS thin film at pH 9.6 and coagulation of granules into larger one with increase of pH. The results reveal the obvious effect of ammonia concentration on the optical properties, crystallite size, elastic properties and morphology of the surface of the films.

An improved, easier, and cost-effective pentacene double-layer technique with better performance is proposed in this paper to enhance the air stability of the pentacene-based organic thin-film transistors (OTFTs). This paper will definitely help to solve the instability issue of pentacene-based OTFTs so that they can be used in long durable low-cost flexible organic display.

A new technique called a pentacene double layer is proposed in this paper to enhance the air stability of the pentacene-based OTFTs. A practically insulating amorphous layer of pentacene (P-II) deposited at very low substrate temperature is used as protective layer above the pentacene active layer (P-I) so that an encapsulation layer of SiO2 can be deposited without damaging the active layer. This technique reduced the probability of interaction of O2 and H2O with the active pentacene layer to zero during fabrication of the devices (multiple breakdown process), and hence can be fabricated without using nitrogen ambient chamber as a result the devices become highly cost effective.

In this article, we study Bell numbers and Uppuluri Carpenter numbers. We obtain various expressions and relations between them. These include polynomial recurrences and expressions as determinants of certain matrices of binomial coefficients.

In this study, we report the development of a new route for the synthesis of polymer–PbS nanocomposite thin film by a novel solar irradiation-induced reaction which is completely free from any complexing agents and toxic chemicals. The as synthesised polymer–PbS thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–Vis absorption spectroscopy. The optical studies showed a direct allowed band gap of PbS lying in the range 1.78–2.2 eV. The XRD pattern shows the cubic structure of PbS with a lattice parameter of 5.927 A. The SEM micrograph of the as-synthesised PbS thin films shows clusters in a relatively loose compact structure in the poly(vinyl alcohol) matrix and separated by voids, which are clearly observed in the surface. However, after annealing, most of the voids disappear in the PbS surface and it is likely that the clusters coalesce giving rise to an homogeneous and compact film. The PbS thin film after annealing is almost pinhole free and as such suit...

CdS/PVA nanocomposite thin films have been deposited on glass substrates by in situ thermolysis of precursors dispersed in polyvinyl alcohol (PVA). The synthetic technique reported in this study is free from complexing agent and hence no need to control the pH of the solution as in the case of conventional CBD. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV–vis spectroscopy, and photoluminescence (PL) spectra. The XRD and SAED results indicated the formation of CdS nanoparticles with hexagonal phase in the PVA matrix. The photoluminescence and UV–vis spectroscopy revealed that CdS/PVA films showed quantum confinement effect. From the shift in optical band gap, particle sizes were calculated using effective mass approximation (EMA) method and it was found to be in agreement with the results obtained from TEM observations. The SEM results indicated that as grown films were homogeneous with no visible pinholes and cracks. The film prepared at100 °C was found to be suitable for application as a window layer in solar cell.

Avifaunal survey of an Eastern Himalayan biodiversity hotspot area - Jeypore Reserve Forest was carried out from July 2007 to July 2009. Altogether 270 species of avian fauna belonging to 56 families were identified during the survey, of which 58 species were frugivorous, 34 omnivorous, 15 carnivorous, 22 picivorous, five grainivorous and 136 were insectivorous in nature. Of all the bird species recorded, 14 were globally threatened species, five were endemic to this region, 153 were resident common species, 87 resident rare species, 16 migratory common species and 14 were migratory rare species. The endemic species recorded in the study area were Anorrhinus tickelli, Sphenocichla humei, Pellorneum palustre, Yuhina bakeri and Heterophasia pulchella. The globally threatened species include two Critically Endangered, Gyps indicus and Gyps bengalensis, one Endangered, Cairina scutulata, four Vulnerable, Leptoptilos javanicus, Francolinus gularis, Columba punicea, Turdoides longitostris, and seven Near Threatened, Anhinga melanogaster, Arborophila atrogularis, Anorrhinus tickelli, Buceros bicornis, Sphenocichla humei, Pellorneum palustre and Ichthyophaga ichthyaetus.

Tin oxide (SnO2) thin films have been grown on glass substrates using atmospheric pressure chemical vapour deposition (APCVD) method. During the deposition, the substrate temperature was kept at 400°C–500°C. The structural properties, surface morphology and chemical composition of the deposited film were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and Rutherford back scattering (RBS) spectrum. XRD pattern showed that the preferred orientation was (110) having tetragonal structure. The optical properties of the films were studied by measuring the transmittance, absorbance and reflectance spectra between λ = 254 nm to 1400 nm and the optical constants were calculated. Typical SnO2 film transmits ∼ 94% of visible light. The electrical properties of the films were studied using four-probe method and Hall-voltage measurement experiment. The films showed room temperature conductivity in the range 1.08 × 102 to 1.69 × 102 Ω−1cm−1.

We have investigated the pentacene based Organic Thin Film Transistors (OTFTs) with High-k Dielectric Nd2O3. Use of high dielectric constant (high-k) gate insulator Nd2O3 reduces the threshold voltage and sub threshold swing of the OTFTs. The calculated threshold voltage -2.2V and sub-threshold swing 1V/decade, current ON-OFF ratio is 1.7 × 10(4) and mobility is 0.13cm²/V.s. Pentacene film is deposited on Nd2O3 surface using two step deposition method. Deposited pentacene film is found poly crystalline in nature.

Specimen based records of two vespertilionid bats namely Pipistrellus ceylonicus and Tylonycteris fulvida are provided for the first time from the state of Assam in northeastern India. Based on review of existing literature and examinations of museum specimens, we also furnish a checklist of the bat fauna of Assam with distribution, which includes 32 species in 17 genera.

Tetracene thin film transistors with rare earth oxide (Nd 2 O 3 ) as gate dielectric is reported in this work. Rare earth oxide with high dielectric constant and low leakage current improve the performance of the organic thin film transistors (OTFTs). The fabricated tetracene OTFTs have shown good output characteristics with mobility 0.93x10 -4 cm 2 /V.s, ON-OFF ratio 3.3x10 2 , sub-threshold swing 0.06 V/decade and hole concentration 8.74x10 17 cm -3 . Keywords: Organic thin film transistors; Tetracene; Rare earth oxide; Trap density. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i2.4094 J. Sci. Res. 2 (2), 214-220 (2010)

Tropical forests have undergone repeated fragmentation and expansion during Pleistocene glacial and interglacial periods, respectively. The effects of this repeated forest fragmentation in driving vicariance in tropical taxa have been well studied. However, relatively little is known about how often this process results in allopatric speciation, since it may be inhibited by recurrent gene flow during repeated secondary contact, or to what extent Pleistocene-dated speciation results from ecological specialization in the face of gene flow. Here, divergence times and gene flow between three closely-related mosquito species of the Anopheles dirus species complex endemic to the forests of Southeast Asia, are inferred using coalescent based Bayesian analysis. An Isolation with Migration model is applied to sequences of two mitochondrial and three nuclear genes, and 11 microsatellites. The divergence of An. scanloni has occurred despite unidirectional nuclear gene flow from this species into An. dirus. The inferred asymmetric gene flow may result from the unique evolutionary adaptation of An. scanloni to limestone karst habitat, and therefore the fitness advantage of this species over An. dirus in regions of sympatry. Mitochondrial introgression has led to the complete replacement of An. dirus haplotypes with those of An. baimaii through a recent (approximately 62 kya) selective sweep. Speciation of An. baimaii and An. dirus is inferred to have involved allopatric divergence throughout much of the Pleistocene. Secondary contact and bidirectional gene flow has occurred only within the last 100 000 years, by which time the process of allopatric speciation seems to have been largely completed.

BACKGROUND AND PURPOSE: Coinfection of neurocysticercosis (NCC) and Japanese encephalitis (JE) has been advocated as more than a chance occurrence resulting in poor outcome. We undertook this study to determine whether the association of the 2 infections is more than a chance occurrence, to define the imaging characteristics of coinfections, and to explore the synergistic effect of NCC in JE. MATERIALS AND METHODS: Sixty-two patients with JE were studied by MR imaging and CT. CT was done in 53 and MR imaging in 53 patients. The diagnosis of JE was established by CSF JE virus immunoglobulin M capture (MAC) enzyme-linked immunosorbent assay (ELISA). NCC was diagnosed from imaging. A control group of 385 patients was evaluated by imaging for prevalence of NCC in the general population. RESULTS: A significantly high association of NCC with JE (19.3%) was observed in comparison with prevalence of NCC in control subjects (1.04%; P = .0003). JE lesions in coinfection were significantly asymmetric with lateralization to the side of the brain having the maximum NCC or a cyst with edema. The JE lesions in coinfections were more florid, with a significantly higher proportion of abnormal CT scans and more abnormal MR imaging. Coinfections were significantly more common in children. Significantly lower CSF MAC-ELISA units in patients with coinfection reflected low CSF IgM levels, suggesting altered immune status. CONCLUSION: In our series, there was a strong association between JE and NCC, and, thus, this coinfection was more than a chance occurrence.

A giant pedunculate tumour of oesophagus is reported in this study for its rareness. A mate patient aged 48 years was admitted at Jorhat Christian Medical Centre with the complaint of swelling of the neck and dysphagia for a period of 4 months. Clinically the neck swelling looks like swelling of left lobe of thyroid with intrathoracic extension, ENT examination was normal The barium Swallow X-ray of oesophagus showed surprisingly huge dilatation of upper half of the oesophagus. The oesophagoscopy snowed a large mobile infra oesophageal tumour extending from the upper end of the oesophagus upto the mid thoracic region. The neck is explored by collar incission and the cervical oesophagus is opened by longitudinal incission. The tumour is pulled out from the oesophagus and is removed completely by cutting the peduncle which was attached to the tight wall of the oesophagus just below the cricopharynx. The peduncle was about I em in diameter., The length of the tumour was about 3–4 cm at the thoracic part. Post Operative recovery was uneventful. The histopathology report skewed it to be a ease of FIBROLIPOMA.

Food and feeding patterns of great Indian one-horned Rhinoceros (Rhinoceros unicornis) has been studied in Rajiv Gandhi Orang National Park. Altogether 75 species of grasses, 27 species of herbs-shrubs, 27 species of trees, and 9 species of aquatic plants species were identified as a food-plant species of Indian Rhino in the study area. Of the total 75 species of grasses, 48 species had a relative dominance of Saccharum spontaneumwas ranked as the highest relative dominance food-plant among grasses (relative dominance value, 8.45%), while theCyperus pilosusranked the lowest (relative dominance value, 0.08%). Among 27 herbs-shrubs species, three had a relative dominance of Diplazium esculentumwas ranked the highest relative dominance food plants among herbs-shrubs food plants (relative dominance value, 13.83%), while the Solanum viarum was ranked the lowest (relative dominance value, 0.66%). All tree species had a relative dominance of >1.0. TheDalbergia sissooranked the highest among all trees (relative dominance value, 7.94%), while theAnthocephalus cadambaranked the lowest (value, 1.19%). Grasses constituted 86.66% of the total annual diet of Rhino, while the aquatic and woodland species constituted only 13.34% of the total annual diet. Altogether 71 plants species were identified as the Rhino food plants at Rajiv Gandhi Orang National Park. Of which, grasses constituted the highest (42 species), followed by woodland species (trees, herbs-shrubs), (20 species) and aquatic plants (9 species). The grass speciesHemarthria compressacontributed a highest of 11.63%, while the aquatic plantPolygonum hydropiperwas the least of 0.01% in total annual diet. Out of total 42 food-plant species, 20 grass species had no selectivity. TheHemarthria compressawas the top ranking grass species that has been selected as food by the Indian Rhino. Altogether, 36 food-plants (24 grasses, 9 woodland species, and 3 aquatic species) were identified as the staple food that constituted 83.64% of the total annual diet. Study showed that ten top ranking food plants constituted 56.44% and 20 top ranking food plants constituted 72.19% of the total annual diet. Thus, the grass species alone have enough to provide food for Indian Rhino in Rajiv Gandhi Orang National Park. Soil licking and crop depredation by the Indian Rhino were common in the fringe villages in study area.

Anopheles dirus and Anopheles baimaii are closely related species which feed on primates, particularly humans, and transmit malaria in the tropical forests of mainland Southeast Asia. Here, we report an in-depth phylogeographic picture based on 269 individuals from 21 populations from mainland Southeast Asia. Analysis of 1537 bp of mtDNA sequence revealed that the population history of A. baimaii is far more complex than previously thought. An old expansion (pre-300 kyr BP) was inferred in northern India/Bangladesh with a wave of south-eastwards expansion arriving at the Thai border (ca 135-173 kyr BP) followed by leptokurtic dispersal very recently (ca 16 kyr BP) into peninsular Thailand. The long and complex population history of these anthropophilic species suggests their expansions are not in response to the relatively recent (ca 40 kyr BP) human expansions in mainland Southeast Asia but, rather, fit well with our understanding of Pleistocene climatic change there.

The Enterococcus flora of duck intestines consisted of E faecalis and E faecium in ducklings less than eight weeks old and E faecalis, E faecium and E gallinarum in ducks more than eight weeks old. The enterococci were resistant to several antibiotics; chloramphenicol and gentamycin sulphate were the only antibiotics of those tested which were moderately effective. All the Enterococcus species isolates were resistant to the macrolide and lincosamide antibiotics.

Background Malaria is a major cause of morbidity and mortality in Northeast India. As there is limited information available on the potential influence of socio-economic variables on malaria risk, the present study was conducted to assess the influence of demographic factors, the socio-economic status, and knowledge, awareness and education on malaria occurrence. Methods Demographics, malaria knowledge and socio-economic variables were collected in four randomly selected health sub-centres of the Orang primary health centre in the Udalguri district, Assam and the association of malaria occurrence with different variables were analysed. The trend of malaria occurrence for different income groups, proximity to health centres and number of mosquito bites per day was also determined using the chi-square test. Relative risk (RR) for gender, house type, knowledge and use of bed nets was determined using Katz approximation. Results Out of the 71 household heads interviewed, 70.4% (50/71) were males. About half (54.9%, 39/71) of the participants had a history of malaria in the last two years, of which 64.1% (25/39) were males, while 35.9% (14/39) were females (χ2 = 5.13; p = 0.02; RR = 1.79). Of the total population surveyed, 49.3% lived in bamboo houses and 35.2% lived at a distance of >3 km from the nearest health centre. The number of participants who had a history of malaria decreased with an increasing monthly income (p < 0.0001). Malaria occurrence was higher among the households living in bamboo houses (69.2%), as compared to Kucha houses (20.5%) and Pucca houses (10.3%). No significant association was observed between education level and malaria occurrence (p = 0.93). The participants who did not use bed nets regularly reported a high occurrence of malaria infection as compared to those who used bed nets everyday (p < 0.0001). Conclusions Lower income, house type, distance to health sub-centre, knowledge and awareness about malaria, number of mosquito bites per day and use of bed nets were positively associated with malaria occurrence. Increasing the number of health sub-centres close to rural areas, improving the economic status and increasing awareness about malaria prevention measures will thus help to reduce malaria-associated morbidities.