Structural stability of coplanar 1T-2H superlattice MoS2 under high energy electron beam.

Coplanar heterojunctions composed of van der Waals layered materials with different structural polymorphs have drawn immense interest recently due to low contact resistance and high carrier injection rate owing to low Schottky barrier height. Present research has largely focused on efficient exfoliation of these layered materials and their restacking to achieve better performances. We present here a microwave assisted easy, fast and efficient route to induce high concentration of metallic 1T phase in the original 2H matrix of exfoliated MoS2 layers and thus facilitating the formation of a 1T-2H coplanar superlattice phase. High resolution transmission electron microscopy (HRTEM) investigations reveal formation of highly crystalline 1T-2H hybridized structure with sharp interface and disclose the evidence of surface ripplocations within the same exfoliated layer of MoS2. In this work, the structural stability of 1T-2H superlattice phase during HRTEM measurements under an electron beam of energy 300 keV is reported. This structural stability could be either associated to the change in electronic configuration due to induction of the restacked hybridized phase with 1T- and 2H-regions or to the formation of the surface ripplocations. Surface ripplocations can act as an additional source of scattering centers to the electron beam and also it is possible that a pulse train of propagating ripplocations can sweep out the defects via interaction from specific areas of MoS2 sheets.

Human consumption of rumen flukes of cattle in India.

The practice of eating rumen flukes of cattle by a section of people living in Meghalaya, a north eastern State of India, is reported in this communication. Economically backward, some rural people belonging to Khasi, Jaintia, Garo, and Karbi tribes of Christian and Nepali communities who eat beef are accustomed to consuming cooked flukes during breakfast, meals, and also along with rice beer or alcohol. Inspection of the rumens of cattle during slaughter indicated a prevalence of flukes belonging to Cotylophoron, Paramphistomum, Calicophoron, Gastrothylax, and Fischoederius genera in 74% cases, and their collection from rumen ranged approximately from 50 g to 600 g. Biochemical analysis of flukes found 12.60% total protein, 0.78% fat, and 0.87% ash on fresh weight basis. High prevalence of flukes, easy visualization in rumen, their bulk collection, presence of nutritive value, absence of any ill effect, and lack of imminent danger of transmissibility are believed to be the rationales influencing their consumption by people. It is suggested that dietary benefits obtained from flukes might contribute to the energy transfer and inclusion in the food web.

In vitro and in vivo antiplasmodial activity of the root extracts of Brucea mollis Wall. ex Kurz.

Malaria control is compromised worldwide by continuously evolving drug-resistant strains of the parasite demanding exploration of natural resources for developing newer antimalarials. The northeastern region of India is endemic for malaria characterized by high prevalence of drug-resistant Plasmodium falciparum strains. Many plants are used by the indigenous communities living in the northeast India in their traditional system of medicine for the treatment of malarial fever. Folklore claim of antimalarial property of one such plant Brucea mollis was evaluated in vitro and in vivo for antiplasmodial activity. Crude extracts from dried B. mollis root powder were prepared through soxhlet extraction using petroleum ether, methanol, and water sequentially. Methanol extract was further partitioned between chloroform and water. These extracts were tested in vitro against laboratory-adapted chloroquine-sensitive and chloroquine-resistant strains of P. falciparum. In in vitro evaluation, extracts were found more active on the chloroquine-sensitive strain. Methanolic-chloroform (IC(50) 5.1 µg ml(-1)) and methanolic-aqueous (IC(50) 13.9 µg ml(-1)) extracts recorded significant in vitro antiplasmodial activity which was also supported by their promising in vivo activity (ED(50) 72 and 30 mg kg(-1) bw day(-1), respectively) against chloroquine-resistant Plasmodium yoelli N-67 strain in Swiss albino mice. Methanolic-aqueous extract-treated mice survived on average for 14 days that was comparable to the reference drug chloroquine. This is the first report of antiplasmodial activity of B. mollis validating the traditional use of this plant as antimalarial in the northeast India and calls for further detailed investigations.

Low reflectance of carbon nanotube and nanoscroll-based thin film coatings: a case study.

Research on carbon material-based thin films with low light reflectance has received significant attention for the development of high absorber coatings for stray light control applications. Herein, we report a method for the successful fabrication of stable thin films comprised of carbon nanotubes (CNTs) and nanoscrolls (CNS) on an aluminium (Al) substrate, which exhibited low reflectance of the order of 2-3% in the visible and near-infrared (NIR) spectral bands. Changes in the structural and chemical composition of pristine single-walled carbon nanotube (SWCNT) samples were analyzed after each processing step. Spectroscopy, microscopy and microstructural studies demonstrated emergence of CNS and multi-walled carbon nanotubes (MWCNTs) due to the sequential chemical processing of the sample. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) studies revealed the formation of CNS via curling and folding of graphene sheets. Microstructural investigations including SEM and atomic force microscopy (AFM) confirmed the presence of microcavities and pores on the surface of the film. These cavities and pores significantly contribute to the observed low reflectance value of CNTs, CNS compound films by trapping the incident light. Fundamental space environmental simulation tests (SEST) were performed on the coated films, that showed promising results with reflectance values almost unaltered in the visible and NIR spectral bands, demonstrating the durability of these films as potential candidates to be used in extreme space environmental conditions. This study describes the preparation, characterization, and testing of blended CNT and CNS coatings for low-light scattering applications.

Evaluation of PermaNet 2.0 mosquito bednets against mosquitoes, including Anopheles minimus s.l., in India.

Wash resistance and field bioefficacy of PermaNet 2.0 nets, long lasting insecticidal nets, against mosquitoes were evaluated in Assam, northeastern India. After repeated hand washings at 12-day intervals a decline in the mosquito killing ability of PermaNet nets was noted (trend chi2 38.9, p < 0.0001), yet these nets retained good insecticidal efficacy for up to 15 wash cycles, producing a 72.5% mean mortality of An. minimus 24 hours after a 3-minute exposure in World Health Organization cones after 15 washings. Significantly fewer (p < 0.001) mosquitoes were captured in self-baited landing collections in houses equipped with PermaNet nets than in houses using untreated nets in the case of culicines (p < 0.001) but not with anophelines, including An. minimus. The use of PermaNet nets resulted in noticeably fewer bites from Culex pseudovishnui (68.5%) and Cx. quinquefasciatus (70%). Blood-feeding inhibition of mosquitoes in deliberately torn PermaNet nets was seen, indicating a protective effect for those sleeping under these nets. No serious adverse effects of the PermaNet nets were reported by users.

Gastrointestinal nematode larvae in the grazing land of cattle in Guwahati, Assam.

AIM: To know the prevalence of gastrointestinal nematode larvae (L3) in the grazing land of cattle in Guwahati, Kamrup district, Assam. MATERIALS AND METHODS: Pastures were collected and examined for the presence of nematode larvae (L3) from six localities of Guwahati at monthly interval from August 2012 to July 2013. The counted larvae were then expressed as per kg dry matter of herbage (L3/kg DM). RESULTS: Examination of pastures revealed presence of nematode larvae (L3) in pastures throughout the year which varied from 4.5 L3/kg DM in January to a maximum of 106.33 L3/kg DM in August. The L3 of Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp., Cooperia spp., and Mecistocirrus spp. were recovered from pastures. The average pasture larval burden (PLB) was 34.75±3.48 L3/kg DM. Season-wise PLB revealed the presence of 23.89±3.01, 67.54±5.41, 26.67±1.92, and 7.28±0.89 L3/kg DM during pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. Monsoon season has significant (p<0.05) effect on PLB. However, analysis of variance of different locations with respect to season revealed that there was no significant difference but season-wise it was highly significant (p<0.01). Pearson correlation of environmental variables (temperature, relative humidity, and rainfall) with PLB revealed correlation was statistically significant with rainfall (p<0.05). CONCLUSION: This study reveals the presence of five nematode larvae (L3) in the pastures of Guwahati, Assam throughout the year, statistically significant during monsoon season.

Microbial profile of the vitreous aspirates in culture proven exogenous endophthalmitis: A 10-year retrospective study.

PURPOSE: To describe the microbiological profile and clinical outcome in the eyes with culture-proven exogenous endophthalmitis. METHODS: A retrospective analysis of 495 eyes diagnosed as exogenous endophthalmitis was performed over a period of 10 years. In all, aseptically collected aqueous and vitreous aspirates were cultured for bacteria and fungus using standard microbiological techniques. Gram-stain and KOH preparation of the specimens were also performed. The antibiotic susceptibility testing for bacterial isolates was performed by Kirby-Bauer disk diffusion method. The treatment was modified according to the antibiotic sensitivity profile. The final clinical ocular condition was divided into improved, stable or deteriorated. RESULTS: Of 148 culture-proven endophthalmitis eyes, 137 (92.57%) were referred from elsewhere, and 11 (7.43%) belonged to our institute. Aetiologically, 76 (51.35%) eyes were post-cataract surgery, 61 (41.22%) were post-traumatic, 5 (3.38%) eyes post-intravitreal anti-vascular endothelial growth factor injection, 5 associated with corneal diseases and 1 bleb-related endophthalmitis. In 31 (20.95%) eyes, primary intravitreal antibiotics were given outside. The cultures revealed monomicrobial growth in 92.57% (n = 137) and polymicrobial growth in 7.43% (n = 11). Among the bacteria (n = 121, 81.76%), Pseudomonas species dominated overall (n = 32, 27.11%) and post-operative (n = 26, 38.23%) endophthalmitis group. Staphylococcus epidermidis (n = 14, 28%) was prominent in post-traumatic endophthalmitis group. Ninety-two percent (n = 108 isolates) of bacteria were sensitive to vancomycin. In 78 (52.7%) eyes, the clinical ocular condition improved or remained stable while deteriorated in 51 (34.46%). CONCLUSION: A bacterial predominance was observed among causative organisms of exogenous endophthalmitis with Pseudomonas species being the most common. The appropriate surgical intervention improved or stabilised the visual acuity in nearly 50% eyes.

Report of Amblyomma testudinarium in mithuns (Bos frontalis) from eastern Mizoram (India).

Physical examination of semi-domesticated, free ranging mithuns (Bos frontalis) during an animal health check-up and treatment camp organized at Khuwangleng village in the Champhai district of Mizoram, India and adjacent to Myanmar Border revealed presence of unusually large blood engorged ticks attaching to the dewlap and inner aspects of thighs. On the basis of morphological study, the ticks were found indistinguishable from female Amblyomma testudinarium. Prevalence rate of the tick species in mithuns living in the forests was 9.09 % which was recorded as the highest of all reports made earlier from the North Eastern region of India. Medical and veterinary significance of the tick is discussed in the light of available literature.

Larvicidal activity of few select indigenous plants of North East India against disease vector mosquitoes (Diptera: Culicidae).

Mosquitoes are the vectors of several life threatening diseases like dengue, malaria, Japanese encephalitis and lymphatic filariasis, which are widely present in the north-eastern states of India. Investigations on five local plants of north-east India, selected on the basis of their use by indigenous communities as fish poison, were carried out to study their mosquito larvicidal potential against Anopheles stephensi (malaria vector), Stegomyia aegypti (dengue vector) and Culex quinquefasciatus (lymphatic filariasis vector) mosquitoes. Crude Petroleum ether extracts of the roots of three plants viz. Derris elliptica, Linostoma decandrum and Croton tiglium were found to have remarkable larvicidal activity; D. elliptica extract was the most effective and with LC50 value of 0.307 µg/ml its activity was superior to propoxur, the standard synthetic larvicide. Half-life of larvicidal activity of D. elliptica and L. decandrum extracts ranged from 2-4 days.

Capsulorhexis in intumescent cataract.

This technique of anterior capsulorhexis is for use in eyes with high intralenticular pressure and absence of red reflex as encountered in intumescent cataract. The initial steps of fashioning the anterior capsular flap and lens decompression are done under the microscope's high magnification and noncoaxial oblique illumination. Intralenticular pressure is controlled by filling the anterior chamber with a viscoelastic agent. Once the lens is decompressed, the capsulorhexis is completed with a capsule forceps and an endoilluminator is used as an oblique source of illumination. This technique allows controlled capsulorhexis in eyes with intumescent cataract.

Epidemiology of Brugia malayi infection and its co-existence with Wuchereria bancrofti in and around Sillaberia PHC, District Midnapur, West Bengal.

Of 2186 persons investigated in thirteen villages of Sillaberia PHC, 19 were found to be infected with Brugia malayi and only one person harboured microfilaria (mf) of Wuchereria bancrofti. Similarly 41 persons exhibited signs and symptoms of chronic filariasis. The mf and disease rates percent worked out to be 0.914 and 1.87 respectively. The earliest ages showing mf and disease manifestations were 3 and 11 respectively. The mean mf density ranged from 2 to 12.2 per 20 cumm of blood. The male and female ratio in terms of mf carriers and chronic cases worked out to be 1.4:1 and 1:2 respectively. The entomological collections revealed a high ten man hour density (163.20) in case of Culex quinquefasciatus and comparatively much lower in case of Mansonia (Mansonioides) annulifera (47.51) and Mansonia (Mansoni oides) uniformis (23.83) respectively. The infection and infectivity rates in case of Mansonia (Mansonioides) annulifera were 6.1 and 1.2 per cent respectively.

Babesia infection in naturally exposed pet dogs from a north-eastern state (Assam) of India: detection by microscopy and polymerase chain reaction.

The objective of the study was to detect Babesia infections in pet dogs of a north-eastern state of India. The diagnostic efficacy of Babesia infection by polymerase chain reaction (PCR) technique has been compared with microscopy examination. For this, a total of 111 blood samples of pet dogs presented at clinical complex of the College of Veterinary Science, Guwahati, Assam with clinical signs suspected for Babesia infection subjected to the study. A total of 44 (39.63 %) dogs were diagnosed as positive for Babesia infections after microscopic examination. Among these, Babesia canis infection was diagnosed in 5 dogs (4.50 %) and B. gibsoni infection in 39 (35.13 %) dogs microscopically in Giemsa stained blood smears. Molecular diagnosis using PCR detected 63 (56.75 %) dogs positive for Babesia infection. Single infection with B. canis was found in 9 (8.10 %) dogs while B. gibsoni alone was detected in 3 (2.70 %) dogs. Mixed infections by both these species were detected in 51 (45.94 %) dogs. Overall, PCR detected 54 (48.64 %) dogs as B. gibsoni and 60 (54.05 %) dogs as B. canis positive.

Baseline study of Siang River water in Pasighat, Arunachal Pradesh (India).

A systematic study was carried out over all the seasons for two consecutive years (March 2003 to May 2005) to monitor the most important physico-chemical parameters of the Siang river water, Arunachal Pradesh, India in order to establish the baseline data of the river water. Water samples were collected from nine locations covering a stretch of 45 km of the river, in and around Pasighat, the district headquarters of East Siang District, Arunachal Pradesh. Alarge number of parameters such as temperature, pH, electrical conductivity, total solids, total dissolved solids, total hardness, dissolved oxygen, chlorides, sulphates, phosphates, silicates, bicarbonates, sodium, potassium, calcium and magnesium were found to be well within the permissible limits for drinking water. Concentration of iron is very high in the study stretch, but all other metals were well below the maximum permissible limits. Levels of metals such as Cu, Co, Cr, Mn, Ni, Pb and Zn are attributed to lithogenic contribution in absence of industrial and large scale agricultural activity in the study area.

Spatial distribution and r-DNA second internal transcribed spacer characterization of Anopheles dirus (Diptera: Culicidae) complex species in north-east India.

The identity and distribution of the prevalent member species of the Anopheles dirus complex mosquitoes in the north-eastern region of India was investigated in a cross-sectional study. We altogether collected 267 individuals of An. dirus s.l. from 27 forested/forest fringed locations spread across the seven north-eastern states, identified the species using a ribosomal DNA (r-DNA) second internal transcribed spacer (ITS2) based allele specific polymerase chain reaction (ASPCR) method and sequenced the ITS2 locus in a sub set of mosquitoes. An. baimaii was identified as the main, almost exclusive (266/267), species of the Dirus complex throughout the north-east India with no intraspecific variation in the 479 base pair long ITS2 sequences in 59 of the 60 individuals sequenced. Ribosomal DNA of one individual from Assam state did not amplify in the ASPCR, possessed 786 base pair long ITS2 sequence and showed 99.7% similarity with the sequence of An. dirus species D (An. baimaii) from Yunnan province of China, later referred to as species X of the Dirus complex. These observations suggest the presence of another, possibly the new, species of the Dirus complex, sympatric with An. baimaii, in Assam warranting investigations on its distribution, biology and role in human malaria transmission in north-east India.

Probing atomic migration in nanostructured multilayers: application of X-ray standing wave fields.

X-ray standing wave fields, excited in periodic nanostructured multilayers during Bragg diffraction, have been used to probe atomic migration in multilayers. Ion beam induced migration of Fe impurity atoms from the C layers to the Pt layers in a Pt(Fe)/C(Fe) multilayer, where each layer is about 2 nm thick, has been detected. With a depth resolution better than 0.2 nm of this technique, the direction of Fe migration (here outward) and the change of Fe concentration in C (also Pt) layers have been determined. The results of such measurements are important for understanding the properties of multilayers, for example, the evolution of ferromagnetism in the present example [Dev, Microelectron. Eng. 83, 1721 (2006)10.1016/j.mee.2006.01.230].