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The burden of dengue virus infections increased globally during recent years. Though India is considered as dengue hyper-endemic country, limited data are available on disease epidemiology. The present study includes molecular characterization of dengue virus strains occurred in Hyderabad, India, during the year 2014. A total of 120 febrile cases were recruited for this study, which includes only children and 41 were serologically confirmed for dengue positive infections using non-structural (NS1) and/or IgG/IgM ELISA tests. RT-PCR, nucleotide sequencing and evolutionary analyses were carried out to identify the circulating serotypes/genotypes. The data indicated a high percent of severe dengue (63%) in primary infections. Simultaneous circulation of all four serotypes and co-infections were observed for the first time in Hyderabad, India. In total, 15 patients were co-infected with more than one dengue serotype and 12 (80%) of them had severe dengue. One of the striking findings of the present study is the identification of serotype Den-1 as the first report from this region and this strain showed close relatedness to the Thailand 1980 strains but not to any of the strains reported from India until now. Phylogenetically, all four strains of the present study showed close relatedness to the strains, which are reported to be high virulent.
Castor is an industrially important oilseed crop. Vascular wilt caused by the soil borne fungus Fusarium oxysporum f. sp. ricini is a serious disease of castor. Use of resistant cultivars is the only viable option for management of wilt disease problem in castor production. Excellent sources of resistance to wilt have been found in castor germplasm. In this study, a set of four castor inbred lines (48–1, CI-1, AP42 and AP48) was characterized for inheritance of resistance to wilt by studying segregating populations generated by crossing these inbred lines with eight different susceptible genotypes. An artificial screening method (sick pot) with a new scoring system (days to wilt) was used for evaluation of plant progenies for reaction to the pathogen infection. The reaction of F1s indicated that the nature of resistance in 48–1, CI-1 and AP48 is recessive whereas it was dominant in AP42. Inheritance results from eight F2 populations showed that resistance to wilt is conferred by a single locus in one population and at least two loci, which interact in complementary way, in other seven populations. Different modes of inheritance were also observed when the same resistant source was crossed with different susceptible parents, indicating the possible role of genetic backgrounds in determining resistance. Overall, the results suggested that Mendelian resistance to wilt is predominant in the castor genotypes, which can be exploited for breeding cultivars. Particularly, AP42 with dominant nature of resistance will be of great interest to hybrid breeding.
The influence of temperature-dependent fluid properties on flow and heat transfer of an electrically conducting fluid over a stretching sheet with variable thickness in the presence of a transverse magnetic field is analyzed. Using similarity transformations, the governing coupled non-linear partial differential equations (momentum and energy equations) are transformed into a system of coupled non-linear ordinary differential equations and are solved numerically by Keller-box method. For increasing values of the wall thickness parameter, the analysis reveals quite interesting flow and heat transfer patterns. The effects of the temperature dependent viscosity, the wall velocity power index, the thermal conductivity, the wall temperature parameter and the Prandtl number on the flow and temperature fields are presented. The obtained numerical results are compared with the available results in the literature for some special cases and are found to be in excellent agreement. The skin friction and the wall temperature gradient are presented for different values of the physical parameters and the salient features are analyzed.
Herpes virus infections can cause cognitive impairment during and after acute encephalitis. Although chronic, latent/persistent infection is considered to be relatively benign, some studies have documented cognitive impairment in exposed persons that is untraceable to encephalitis. These studies were conducted among schizophrenia (SZ) patients or older community dwellers, among whom it is difficult to control for the effects of co-morbid illness and medications. To determine whether the associations can be generalized to other groups, we examined a large sample of younger control individuals, SZ patients and their non-psychotic relatives (n=1852).
Using multivariate models, cognitive performance was evaluated in relation to exposures to herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2) and cytomegalovirus (CMV), controlling for familial and diagnostic status and sociodemographic variables, including occupation and educational status. Composite cognitive measures were derived from nine cognitive domains using principal components of heritability (PCH). Exposure was indexed by antibodies to viral antigens.
PCH1, the most heritable component of cognitive performance, declines with exposure to CMV or HSV-1 regardless of case/relative/control group status (p = 1.09 × 10−5 and 0.01 respectively), with stronger association with exposure to multiple herpes viruses (β = −0.25, p = 7.28 × 10−10). There were no significant interactions between exposure and group status.
Latent/persistent herpes virus infections can be associated with cognitive impairments regardless of other health status.
The preparation of hydrogenated amorphous silicon by the radio-frequency (RF) glow discharge technique is shown to be strongly dependent on the plasma excitation frequency. We have investigated the influence of this parameter on the deposition rate, on the hydrogen content and on the opto-electronic properties of the amorphous silicon films, over the range 25 to 150 MHz. A large variation of the deposition rate is observed, while most of the material properties remain practically unchanged. The results should be of considerable interest for mass production of low-cost amorphous silicon thin film devices.
Recent findings concerning the surface chemistry of Cu(I)) and Cu(II) betadiketonate precursors on metal and TiN surfaces are reviewed. Interactions of Cu(I) hexafluoroacetylacetonate (L) (Cu(I)(hfac)(L); L=Lewis base) with the surface result in an adsorbed Cu(I)hfac intermediate. Cu(II)(hfac)2 adsorbtion yields the Cu(I)hfac intermediate plus adsorbed hfac. Subsequent exposure to atomic hydrogen volatilizes the adsorbed hfac and results in the reduction of Cu(I) via disproportionation: 2Cu(I)(hfac) ⇒ Cu(0) + Cu(II)(hfac)2 (desorbed). These results demonstrate that disproportionation can occur on contaminant free surfaces under UHV conditions, and that the mechanisms for Cu(I) and Cu(II)/H2 film growth are similar. Implications for selectivity and low temperature deposition are explored. Potential shortcomings of TiN as an adhesion/diffusion barrier are also discussed.
We have investigated the influence of substrate temperature on the optoelectronic and structural properties of heavily doped μc-Si:H, prepared with the Very High Frequency Glow Discharge process. At substrate temperatures as low as 160°C we obtain, for films with 0.5μm thickness, maximum conductivities of 100 S/cm and 20 S/cm for <n> and <p> material, respectively. Starting from these values the deposition parameters were optimised for ultrathin layers having thicknesses in the range of 100 to 500Å. We observe that boron doping plays a critical role in the crystallisation of ultrathin films. The thinnest layers investigated so far show conductivities of 0.2 S/cm at d=100Å for <n>, and 0.2 S/cm at d=250Å for <p> material. These properties make μc-Si:H films attractive candidates to form tunnel junctions in tandem solar cells.
In doped and undoped microcrystalline silicon prepared with Very High Frequency Glow Discharge, hydrogen is found to be mainly located at the grain boundaries from where it desorbs easily at low annealing temperatures. In undoped material hydrogen evolution peaks are between 400°C and 500°C. Upon doping, a new major peak appears at 300°C and a strong reduction of the typical Si-H infrared absorption bands are found for doped samples when annealed up to 300°C. This is accompanied by an increase of the conductivity due to either de-passivation of dopants in the crystallites or a favourable reconstruction at the grain boundaries. Hydrogen profiles show a hydrogen depletion at the film/air interface that is more profound in doped material, thus correlating with the appearance of the low temperature evolution peak. The high free carrier density in the crystallites of the doped material gives rise to strong optical absorption. Although correlating nicely with conductivity, the free carrier absorption cannot be evaluated simply in terms of die Drude theory. In view of the high conductivities and the dominance of Si-H surface bonds we argue that our material does not contain a large amount of amorphous tissue.
The growth morphology and microstructure of SiC/AlN/6H-SiC, SiC/AlN/SiC/Si, and SiC/AlN/Si heterostructures grown by LPCVD were studied using transmission electron microscopy. The SiC/AIN bilayers grown on 6H-SiC substrates were single crystalline and comprised of 3C-SiC and 2H-AlN. The epitaxial relationship between 2H-AlN and 6H-SiC is AlN//SiC. The SiC/AlN/SiC trilayers and the SiC/AIN bilayer grown on (001)Si were composed of 3H-SiC and 2H-AlN. However, the 2H-AlN layer was polycrystalline even though the (001)3C-SiC was single crystalline. The preferred orientation of the AlN layers in SiC/AlN/SiC/Si and SiC/AlN/Si are  and , respectively. The AlN/3C-SiC interface is relatively sharp compared to the AIN/Si interface in which an amorphous layer close to the interface was observed. In general, the polycrystalline AlN structure has two distinct layers: (1) nucleation layer and (2) bulk layer. High resolution lattice images of the polycrystalline AlN showed amorphous areas and small misoriented crystallites in the nucleation layer. The bulk layer consists of preferentially oriented large columnar grains.
The deposition of GaAs by MBE at low temperatures results in a material of unique properties. However, up to now the control and understanding of the electrical and structural properties are unsatisfactory. To investigate the influence of growth parameters on the formation of point defects and electrical properties, the substrate temperature and the As/Ga flux ratio were systematically varied. In a well defined parameter range the lattice expansion was found to be dominated by the formation of As antisite defects. After annealing a high resistivity is obtained independent of the growth conditions. A strong influence of the growth temperature on the band conduction mechanism is observed, whereas a variation of the As/Ga flux ratio induces only slight changes of the temperature dependence of the conductivity.
Thin films of Bi2VO5.5 (BVO), a vanadium analog of the n = I member of the Aurivillius family, have been prepared by pulsed laser deposition. The BVO films grow along the  direction on LaNiO3(LNO) and YBa2Cu3O7 (YBCO) electrode buffer layers on LaA- IO3(LAO) substrates as obtained from X-ray diffraction studies. The microstructure of the films and of the interfaces within the film and between the film and the substrate were characterized using transmission electron microscopy. The in-plane epitaxial relationship of the rhombohedral LNO on perovskite LAO was  LNO //  LAO and  LNO //  LAO. High resolution lattice images showed a sharp interface between LNO and LAO. However, the LNO film is twinned with a preferred orientation along the growth direction. The BVO layer is single crystalline on both LNO/LAO and YBCO/LAO with the caxis parallel to the growth direction except for a thin layer of about 400 Å at the interface which is polycrystalline.
We report on the room temperature and the low temperature ( 77 K ) study of highly Si doped MBE grown bulk Al.2Ga.8As layers by Photoluminescence ( PL ), Hall, X-Ray and Electrochemical Voltage Profiler ( ECV ) technique. The room temperature PL spectra shows the presence of an asymmetric broad peak in the low energy side whose Full Width at Half Maxima (FWHM) and intensity increases with the doping level. The broad peak has been found to be a combination of two individual peaks, one arising out of the DX center related recombinations and the other due to some Silicon related complex acceptor sites. The low temperature PL also shows a ‘strange peak’ near the Al2Gas8As band edge luminescence peak for wafers grown at 600°C. This peak which increases in intensity at a very rapid rate with falling temperature and shift very rapidly with temperature can be attributed to some AIGaAs growth defect related recombination center, depending on the growth temperature.
Molecular materials comprised of inorganic:organic composites are of considerable interest in photonics, optoelectronics and biophotonics. We report broad band lasing and tunable filters in sol-gel processed poly (p-phenylene vinylene) PPV: Silica composites. Optical power limiting in near IR wavelength region is also reported in dye doped PPV: silica multiphasic nanocomposites. For making hybrid inorganic: organic composites the reverse micelle mediated synthesis technique has been exploited to synthesize dye encapsulated metal oxide particles, thiocresol capped CdS clusters, Cul and AgI nanoparticles. These particles were dispersed in polymeric matrix for applications in photoconductivity and photorefractive measurements.
Over the past five years there has been a renaissance in design studies of chromophores with the possibility of enhanced two-photon absorption (TPA). While two-photon absorption has been described for molecules such as laser dyes in solution for a number of years1, it has only been recently that researchers have attempted detailed structure-property relationships to elucidate how new chromophores with greatly enhanced two-photon cross-sections might be designed. Since the intrinsic cross-sections are related to the Im component of the third order optical nonlinearity, it should come as no surprise that much of the previous work in the literature which focused on structure-property relationships for molecules with enhanced NLO response might be applicable to the design of new TPA chromophores. In this presentation we will review our recent studies in this area, and our rationale for the applicability of dendritic strctures based on photonic-active repeat units for enhancment of two-photon absorption, particularly in the area of optical power limiting applications.
This paper presents a novel method to create and integrate micro-machined devices and high aspect-ratio (height-to-width ratio) microstructures in which the microstructures are built up using multiple layers of photopolymer film and/or viscous solution. Very high aspect-ratio 2-and 3-dimensional (2-D and 3-D) microstructures were constructed by stacking photo-imageable polymer films. Such films may be dry films applied by lamination or solution layers applied by bar coating, or doctor blade coating. Photolithography is used in both cases to define the microstructure. This additive process of thin-film micromachining facilitates high aspect-ratio microstructure fabrication. We have demonstrated structures of up to 12-layers comprising 2-D arrays of deep trenches (180 μm deep and 25 μm wide) and a 2-layer SU-8 micro-trench array with an aspect ratio up to 36 on glass substrates. Miniaturized structures of interconnected reservoirs as small as 50 μm × 50 μm × 15 μm (∼38 pico liter storage capacity) are also being fabricated, along with a novel 5-layer microfluidic channel array and a vacuum-infiltration process for fluid manipulation. This method has the potential to create functional large-area micro-devices at low-cost and with increased device flexibility, durability, prototyping speed, and reduced process complexity for applications in optoelectronics, integrated detectors, and bio-devices. The novel multi-layer photopolymer dry film and solution process also allows microstructures in micro-electro-mechanical systems (MEMS) to be built with ease and provides the functionality of MEMS integration with electronic devices and integrated circuits (ICs).
The temperature and power dependence of Fermi-edge singularity (FES) in high-density two-dimensional electron gas, specific to pseudomorphic AlxGa1-xAs/InyGa1-yAs/GaAs heterostructures is studied by photoluminescence (PL). In all these structures, there are two prominent transitions E11 and E21 considered to be the result of electron-hole recombination from first and second electron sub-bands with that of first heavy-hole sub-band. FES is observed approximately 5 -10 meV below the E21 transition. At 4.2 K, FES appears as a lower energy shoulder to the E21 transition. The PL intensity of all the three transitions E11, FES and E21 grows linearly with excitation power. However, we observe anomalous behavior of FES with temperature. While PL intensity of E11 and E21 decrease with increasing temperature, FES transition becomes stronger initially and then quenches-off slowly (till 40K). Though it appears as a distinct peak at about 20 K, its maximum is around 7 - 13 K.
Ni-nanowires are fabricated in a two-step electrochemical process. In the first step a porous silicon template with oriented pores perpendicular to the surface is produced. The electrochemical parameters for this etching procedure, like HF-concentration, current-density, etching-time and bath-temperature have to be chosen in a very small regime to obtain the favored structure in a good quality. This mesoporous silicon skeleton with highly oriented pores and homogeneous spatial distribution is filled in a further electrochemical step by a ferromagnetic metal, like Ni. This selforganized Ni-nanowire array is characterized by Auger-spectroscopy to evidence the loading of the pores over the full length. SEM and BSE are used to reveal the orientation of the pores and the homogeneous Ni-filling. By Fourier Transform image processing a predominant quadratic self-organized grouping of the (100) grown pores is identified. An additional investigation method is EDXS to show the element distribution in the sample. Furthermore magnetization measurements are used to generate a model for the Ni-loading in the channels. Not only wires but also granules in the size up to 200 nm are present. IR-spectroscopy investigations are used to compare the bare silicon wafer, the porous silicon (PS) sample and the PS with incorporated Ni at zero and finite magnetic fields.