Gallium nitride nanoparticles for solar-blind detectors

We investigate the properties of GaN semiconducting nanoparticles as a potential candidate for photodetection in the solar- blind region. The photocurrent spectral response is studied spanning the range 1·6-5·5 eV. A significant fraction of the response is in the range 4-5·5 eV. The results are compared to other optical properties and the origins of the features observed in the spectra are speculated upon

Arrested States formed on Quenching Spin Chains with Competing Interactions and Conserved Dynamics

We study the effects of rapidly cooling to T = 0 a spin chain with conserved dynamics and competing interactions. Depending on the degree of competition, the system is found to get arrested in different kinds of metastable states. The most interesting of these has an inhomogeneous mixture of interspersed active and quiescent regions. In this state, the steady-state autocorrelation function decays as a stretched exponential $\sim \exp(-{(t/\tau_{o})}^{{1}\over{3}})$, and there is a two-step relaxation to equilibrium when the temperature is raised slightly.Comment: 4 pages, Latex, 3 postscript figures. Phys. Rev. E to appear (1999

Effect of Heat Treatment on Band Gap of V2O5

The most stable oxide of the vanadium oxide family is V2O5. A lot of research effort is focused on it because it has a multitude of functional applications. Here we report on how the heat treatment (600°C, 5 h, air) affects the microstructure and hence, the band gap of V2O5. The V2O5 powders, initially obtained by simple thermal dissociation (500 °C, 3 h, air) of ammonium metavanadate, followed by heat treatment of pellets; were studied. The structural and optical studies performed using X-ray diffraction (XRD), FESEM and UV-Vis techniques, provide uniquely interesting results which indicate the possibility of band gap tuning by controlling the microstructure

Concurrent infections by all four dengue virus serotypes during an outbreak of dengue in 2006 in Delhi, India

<p>Abstract</p> <p>Background</p> <p>Co-circulation of multiple dengue virus serotypes has been reported from many parts of the world including India, however concurrent infection with more than one serotype of dengue viruses in the same individual is rarely documented. An outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) occurred in and around Delhi in 2006. This is the first report from India with high percentage of concurrent infections with different dengue virus serotypes circulating during one outbreak.</p> <p>Results</p> <p>Acute phase sera from patients were tested for the presence of dengue virus RNA by RT-PCR assay. Of the 69 samples tested for dengue virus RNA, 48 (69.5%) were found to be positive. All the four dengue virus serotypes were found to be co-circulating in this outbreak with DENV-3 being the predominant serotype. In addition in 9 of 48 (19%) dengue virus positive samples, concurrent infection with more than one dengue virus serotype were identified.</p> <p>Conclusion</p> <p>This is the first report in which concurrent infections with different dengue virus serotypes is being reported during an outbreak from India. Delhi is now truly hyperendemic for dengue.</p

Chikungunya Infection in India: Results of a Prospective Hospital Based Multi-Centric Study

Chikungunya (CHIKV) has recently seen a re-emergence in India with high morbidity. However, the epidemiology and disease burden remain largely undetermined. A prospective multi-centric study was conducted to evaluate clinical, epidemiological and virological features of chikugunya infection in patients with acute febrile illness from various geographical regions of India.A total of 540 patients with fever of up to 7days duration were enrolled at Karnataka Institute of Medical Sciences (KIMS), Karnataka (South); Sawai Man Singh Medical College (SMS) Rajasthan (West), and All India Institute of Medical Sciences (AIIMS) New Delhi (North) from June 2008 to May 2009. Serum specimens were screened for chikungunya infection concurrently through RT-PCR and serology (IgM). Phylogenetic analysis was performed using Bioedit and Mega2 programs. Chikungunya infection was detected in 25.37% patients by RT-PCR and/or IgM-ELISA. Highest cases were detected in south (49.36%) followed by west (16.28%) and north (0.56%) India. A difference in proportion of positives by RT-PCR/ELISA with regard to duration of fever was observed (p<0.05). Rashes, joint pain/swelling, abdominal pain and vomiting was frequently observed among chikungunya confirmed cases (p<0.05). Adults were affected more than children. Anti-CHIK antibodies (IgM) were detected for more than 60days of fever onset. Phylogenetic analysis based on E1 gene from KIMS patients (n = 15) revealed ∼99% homology clustering with Central/East African genotype. An amino acid change from lysine to glutamine at position 132 of E1 gene was frequently observed among strains infecting children.The study documented re-emergence of chikungunya in high frequencies and severe morbidity in south and west India but rare in north. The study emphasizes the need for continuous surveillance for disease burden using multiple diagnostic tests and also warrants the need for an appropriate molecular diagnostic for early detection of chikungunya virus

Respiratory viral infections detected by multiplex PCR among pediatric patients with lower respiratory tract infections seen at an urban hospital in Delhi from 2005 to 2007

<p>Abstract</p> <p>Background</p> <p>Acute lower respiratory tract infections (ALRI) are the major cause of morbidity and mortality in young children worldwide. Information on viral etiology in ALRI from India is limited. The aim of the present study was to develop a simple, sensitive, specific and cost effective multiplex PCR (mPCR) assay without post PCR hybridization or nested PCR steps for the detection of respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses (PIV1–3) and human metapneumovirus (hMPV). Nasopharyngeal aspirates (NPAs) were collected from children with ALRI ≤ 5 years of age. The sensitivity and specificity of mPCR was compared to virus isolation by centrifugation enhanced culture (CEC) followed by indirect immunofluorescence (IIF).</p> <p>Results</p> <p>From April 2005–March 2007, 301 NPAs were collected from children attending the outpatient department or admitted to the ward of All India Institute of Medical Sciences hospital at New Delhi, India. Multiplex PCR detected respiratory viruses in 106 (35.2%) of 301 samples with 130 viruses of which RSV was detected in 61, PIV3 in 22, PIV2 in 17, hMPV in 11, PIV1 in 10 and influenza A in 9 children. CEC-IIF detected 79 viruses only. The sensitivity of mPCR was 0.1TCID₅₀for RSV and influenza A and 1TCID₅₀for hMPV, PIV1, PIV2, PIV3 and Influenza B. Mixed infections were detected in 18.8% of the children with viral infections, none detected by CEC-IIF. Bronchiolitis was significantly associated with both total viral infections and RSV infection (p < 0.05). History of ARI in family predisposed children to acquire viral infection (p > 0.05).</p> <p>Conclusion</p> <p>Multiplex PCR offers a rapid, sensitive and reasonably priced diagnostic method for common respiratory viruses.</p

Direct Substrate Delivery into Mitochondrial-Fission Deficient Pancreatic Islets Rescues Insulin Secretion

In pancreatic beta cells, mitochondrial bioenergetics control glucose-stimulated insulin secretion (GSIS). Mitochondrial dynamics are generally associated with quality control, maintaining the functionality of bioenergetics. By acute pharmacological inhibition of mitochondrial fission protein Drp1, we here demonstrate that mitochondrial fission is necessary for GSIS in mouse and human islets. We confirm that genetic silencing of Drp1 increases mitochondrial proton leak in MIN6 cells. However, our comprehensive analysis of pancreatic islet bioenergetics reveals that Drp1 does not control insulin secretion via its effect on proton leak but instead via modulation of glucose-fuelled respiration. Notably, pyruvate fully rescues the impaired insulin secretion of fission-deficient beta cells, demonstrating that defective mitochondrial dynamics solely impact substrate supply upstream of oxidative phosphorylation. The present findings provide novel insights in how mitochondrial dysfunction may cause pancreatic beta cell failure. In addition, the results will stimulate new thinking in the intersecting fields of mitochondrial dynamics and bioenergetics, as treatment of defective dynamics in mitochondrial diseases appears to be possible by improving metabolism upstream of mitochondria

Co-infections with Chikungunya Virus and Dengue Virus in Delhi, India

Aedes aegypti mosquitoes are common vectors for dengue virus and chikungunya virus. In areas where both viruses cocirculate, they can be transmitted together. During a dengue outbreak in Delhi in 2006, 17 of 69 serum samples were positive for chikungunya virus by reverse transcription–PCR; 6 samples were positive for both viruses

aDolescents gEnder surVey, rEsponsible coupLes evaluatiOn, and capacity building Project in India (DEVELOP): a study protocol [version 1; peer review: 2 approved with reservations]

Gender-based violence against women is a serious concern in India. This affects the health and wellbeing of victims and their dependents. Published evidence has documented a variety of reasons for such violence in Indian societies, paving a pathway to design, implement, and evaluate intervention models to address this issue. DEVELOP is a research study designed by UK and Indian research teams to plan future projects to address gender-based discrimination and violence against women and girls in India. This study protocol provides detailed information on the objectives, research methods, data collection, storage, analysis, and dissemination plans of the DEVELOP. The first component is a survey of adolescent boys and girls from rural areas of Maharashtra state of India to understand their gender equality related knowledge and beliefs. The insight gathered will be used to design interventions targeted at adolescent populations through future research and development programmes. Secondly, an evaluation of the ‘Responsible Couples’ project will be conducted to assess its success and challenges, and to design suitable programme activities and models. The ‘Responsible Couples’ project is implemented in 40 villages of Maharashtra state to improve relationships in married couples, prevent violence against women, intervene during violence, and to provide support services for women and their family members. Research findings will be disseminated though public engagement events in India, international conferences, and peer reviewed publications. This will impact on the policy and work models of Indian partners to plan future project investments. Research findings will be also useful for local government authorities and non-government agencies striving to advance gender equality