Showing papers by "Cochin University of Science and Technology published in 2005"

The Importance of Toll-Like Receptor 2 Polymorphisms in Severe Infections

Abstract: Toll-like receptor 2 (TLR2) is a member of the TLR family, which plays a central role in the innate immune response to a wide variety of microorganisms. Animal studies have shown that TLR2-knockout mice are more susceptible to septicemia due to Staphylococcus aureus and Listeria monocytogenes, meningitis due to Streptococcus pneumoniae, and infection with Mycobacterium tuberculosis, suggesting that functional TLR2 polymorphisms may impair host response to a certain spectrum of microbial pathogens. In humans, 2 polymorphisms in the exon part of TLR2, which attenuate receptor signaling, enhance the risk of acute severe infections, tuberculosis, and leprosy. Because gram-positive bacteria have became the first cause of severe infections, including septic shock, knowledge of the role that alteration or lack of TLR2 function plays in the pathogenesis of infectious diseases could contribute to the design of new therapeutic strategies, including prevention, pharmacological intervention, and vaccine development.

(1-x)MgAl2O4-xTiO2 dielectrics for microwave and millimeter wave applications

Abstract: The MgAl2O4 ceramics were prepared by the conventional solid-state ceramic route and the dielectric properties studied in the microwave frequency region (3–13 GHz). The phase purity and crystal structure were identified using the X-ray diffraction technique. The MgAl2O4 spinel ceramics show interesting microwave dielectric properties (er=8.75, Quxf=68900 GHz (loss tangent = 0.00017 at 12.3 GHz), τf=-75 ppm/°C). The MgAl2O4 has high negative τf, which precludes its immediate use in practical applications. Hence the microwave dielectric properties of MgAl2O4 spinels were tailored by adding different mole fractions of TiO2. The er and Q factor of the mixed phases were increased with the molar addition of TiO2 into the spinel to form mixtures based on (1-x)MgAl2O4-xTiO2 (x=0.0-1.0). For x=0.25 in (1-x)MgAl2O4-xTiO2, the microwave quality factor reaches a maximum value of Quxf=105400 GHz (loss tangent = 0.00007 at 7.5 GHz) where er and τf are 11.035 and -12 ppm/°C, respectively. The microwave dielectric properties of the newly developed 0.75MgAl2O4-0.25TiO2 dielectric is superior to several commercially available low loss dielectric substrates.

Spectroscopic characterization of laser-induced tin plasma

Abstract: Optical emission spectroscopic studies have been carried out on a tin plasma generated using 1064-nm, 8-ns pulses from a Nd:yttrium aluminum garnet laser. Temperature and density were estimated from the analysis of spectral data. The temperature measurements have been performed by Boltzmann diagram method using singly ionized Sn lines, while density measurements were made using the Stark broadening method. An initial temperature of 3.2 eV and density of 7.7×1017cm−3 were measured. Temporal and spatial behaviors of electron temperature and density in the laser-generated tin plasma have been analyzed. Time evolutions of density and temperature are found to decay adiabatically at early times. The spatial variation of density shows approximately 1∕z dependence. The time-integrated temperature exhibits an appreciable rise at distances greater than 7 mm. This may be caused by the deviation from local thermodynamic equilibrium at larger distances from the target surface.

On the properties of indium doped ZnO thin films

Abstract: Thin films of undoped and In-doped zinc oxide, prepared using chemical spray pyrolysis, were investigated using x-ray diffraction, optical transmission and absorption spectra, SEM, resistivity measurements, x-ray photoelectron spectroscopy and photoluminescence studies. A doping level of 1 at% indium was found to give lowest resistive films and enhanced optical transmission. But increasing the doping percentage resulted in lower optical transmission. XPS investigations revealed the presence of elemental chlorine in the In-doped film. Undoped ZnO thin films gave a strong blue-green emission. Doping with indium apparently resulted in a competitive phenomenon that overshadows the blue-green emission and gave rise to three emissions at 408, 590 and 688 nm.

Effect of Nonstoichiometry on the Structure and Microwave Dielectric Properties of Ba(Mg0.33Ta0.67)O3

Abstract: The effect of a slight A- and B-site cation nonstoichiometry on the structure, densification, and microwave dielectric properties of Ba(Mg1/ 3Ta2/3)O3 (BMT) was investigated. Magnesium and barium nonstoichiometric compositions based on Ba(Mg0.33-xTa0.67)O3 [x = −0.015, −0.010, −0.005, 0.0, 0.005, 0.010, 0.015, 0.020, 0.025, and 0.030] and Ba1-x(Mg0.33Ta0.67)O3 [x = −0.015, −0.010, −0.005, 0.0, 0.0025, 0.005, 0.0075, 0.010, 0.015, 0.020, 0.025, and 0.030] were prepared using the conventional solid-state ceramic route. The lattice distortion and cation ordering were determined using X-ray diffraction technique. The phase composition and surface morphology were studied by EDX and scanning electron microscopy techniques, respectively. The sintered samples were characterized in the microwave frequency range using the resonance technique. It is found that a slight barium or magnesium deficiency can improve density, microwave dielectric properties, and cation ordering, while the addition of excess ions deteriora...

Fenneropenaeus indicus is protected from white spot disease by oral administration of inactivated white spot syndrome virus

Abstract: Fenneropenaeus indicus could be protected from white spot disease (WSD) caused by white spot syndrome virus (WSSV) using a formalin-inactivated viral preparation (IVP) derived from WSSV-infected shrimp tissue. The lowest test quantity of lyophilized IVP coated onto feed at 0.025 g(-1) (dry weight) and administered at a rate of 0.035 g feed g(-1) body weight d(-1) for 7 consecutive days was sufficient to provide protection from WSD for a short period (10 d after cessation of IVP administration). Shrimp that survived challenges on the 5th and 10th days after cessation of IVP administration survived repeated challenges although they were sometimes positive for the presence of WSSV by a polymerase chain reaction (PCR) assay specific for WSSV. These results suggest that F. indicus can be protected from WSD by simple oral administration of IVP.

Effect of fluorine doping on structural, electrical and optical properties of ZnO thin films

Abstract: We studied effect of fluorine doping on ZnO thin films prepared using chemical spray pyrolysis technique. Structural, electrical and optical characterization techniques were used for the study. Both doped and undoped films showed preferential orientation along (0 0 2) plane. Optical absorption studies indicated a decrease of energy band gap and optical transmission increased with increase in fluorine doping. PL spectrum of undoped sample has a single broad peak at 517 nm while three additional peaks appeared for fluorine-doped film. Electrical resistivity and photosensitivity decreased considerably on doping. Temperature dependent conductivity studies revealed that prominent shallow donor levels are Zn in interstitial and regular lattice positions.

Prognostic value of relative adrenal insufficiency after out-of-hospital cardiac arrest.

Abstract: Objective To assess the prevalence of relative adrenal insufficiency in patients successfully resuscitated after cardiac arrest, and its prognostic role in post-resuscitation disease.

Underlying Disorders and Their Impact on the Host Response to Infection

Abstract: Underlying disorders, especially those that chronically impair immune host response (e.g., cancers and hematologic malignancies) but also those that acutely impair this response (e.g., major surgery and multiple trauma), increase the incidence of infection and alter the outcome of patients with sepsis. As a part of innate immunity, inflammatory and coagulation responses are lower in patients with underlying disorders than in patients without such disorders, whereas the need for vasopressors and mechanical ventilation is more frequent. Although these patients are older, age-related defects do not appear to be responsible for this lower response, because innate immunity is usually up-regulated in the elderly. Innate immunity seems to be negligibly affected by the direct consequences of underlying disorders, but underlying disorder-related chronic organ insufficiency certainly participates in the observed organ dysfunction, overestimating the infectious insult by itself. Although innate immunity seems not to be actually blunted in patients with underlying disorders, the underlying disorder itself contributes to the severity of the physiological response to sepsis, thereby resulting in a worse outcome.

Defect analysis of sprayed β-In2S3 thin films using photoluminescence studies

Abstract: In this paper we report for the first time the results of photoluminescence (PL) studies on thin films of a β-In2S3 compound semiconductor, grown using a chemical spray pyrolysis (CSP) technique. PL emission in the wavelength range 550–900 nm was recorded using a 488 nm line from a Ar+ laser as the excitation source. There were two PL bands, centred at 568 nm (band A) and 663 nm (band B). A shift in the PL peak energy and full width at half maximum of the former band due to a variation in temperature strongly suggested that the emission followed the Cartesian coordinate (CC) model of luminescence, while the latter was found to have arisen from transitions between a donor–acceptor pair. Band A was most dominant in the sulfur-deficient sample and hence associated with a sulfur vacancy, while band B was dominant in the indium-rich sample and hence linked with indium interstitials. The proposed energy level scheme allowed us to interpret the recombination processes in β-In2S3 thin films.

Rapid erosion of the coast of Sagar island, West Bengal - India

Abstract: The coastal zone of the Sagar island has been studied. The island has been subjected to erosion by natural processes and to a little extent by anthropogenic activities over a long period. Major landforms identified in the coastal area of the Sagar island are the mud flats/salt marshes, sandy beaches/dunes and mangroves. The foreshore sediments are characterized by silty, slightly sandy mud, slightly silty sand and silty sand. Samples 500 m inland from high waterline are silty slightly sandy mud, and by clayey slightly sandy mud. The extent of coastline changes are made by comparing the topographic maps of 1967 and satellite imageries of 1996, 1998 and 1999. Between 1967 and 1999 about 29.8 km2 of the island has been eroded and the accreted area is only 6.03 km2. Between 1996 and 1998 the area underwent erosion of 13.64 km2 while accretion was 0.48 km2. From 1998 to 1999, 3.26 km2 additional area was eroded with meager accretion. Erosion from 1997 to 1999 was estimated at 0.74 km2 /year; however, from 1996 to 1999, the erosion rate was calculated as 5.47 km2/year. The areas severely affected by erosion are the northeastern, southwestern and southeastern faces of the island. As a consequence of coastal erosion, the mud flats/salt marshes, sandy beaches/dunes and mangroves have been eroded considerably. Deposition is experienced mainly on the western and southern part of the island. The island is built primarily by silt and clay, which can more easily be eroded by the waves, tides and cyclonic activities than a sandy coast. Historic sea level rises accompanied by land subsidence lead to differing rates of erosion at several pockets, thus periodically establishing new erosion planes.

Compact planar multiband antenna for GPS, DCS, 2.4/5.8 GHz WLAN applications

Abstract: A compact single-feed multiband planar antenna configuration suitable for GPS, DCS, 2.4/5.8 GHz WLAN applications is presented. The antenna has dimensions 38/spl times/3/spl times/1.6 mm and offers good radiation and reflection characteristics in the above frequency bands. The antenna has a simple geometry and can be easily fed using a 50 /spl Omega/ coaxial probe.

Hydrography and water masses in the southeastern Arabian Sea during March-June 2003

Abstract: This paper describes the hydrographic observations in the southeastern Arabian Sea (SEAS) during two cruises carried out in March–June 2003 as part of the Arabian Sea Monsoon Experiment. The surface hydrography during March–April was dominated by the intrusion of low-salinity waters from the south; during May–June, the low-salinity waters were beginning to be replaced by the highsalinity waters from the north. There was considerable mixing at the bottom of the surface mixed layer, leading to interleaving of low-salinity and high-salinity layers. The flow paths constructed following the spatial patterns of salinity along the sections mimic those inferred from numerical models. Time-series measurements showed the presence of Persian Gulf and Red Sea Waters in the SEAS to be intermittent during both cruises: they appeared and disappeared during both the fortnight-long time series.

Broadband Cylindrical Dielectric Resonator Antenna Excited by Modified Microstrip Line

Abstract: The impedance bandwidth of a high permittivity cylindrical dielectric resonator antenna excited by a microstrip line was significantly improved by modifying the feed geometry. The 10 dB return loss bandwidth is enhanced from 12 to 26% without much affecting the gain and other radiation properties of the antenna. Good agreement has been observed between the predicted and measured results.

Observed variability of sea surface salinity and thermal inversions in the Lakshadweep Sea during contrast monsoons

Abstract: [1] The sea surface salinity (SSS) of the Lakshadweep Sea (LS) shows large seasonal variability due to horizontal advection of low (high) salinity waters from south (north) during winter (summer) monsoon. The measurements made in the LS during the Arabian Sea Monsoon Experiment (ARMEX), have shown a dramatic drop of 3.4 PSU in the SSS during the winter following an active (2003) monsoon that is double that of the drop of 1.7 PSU observed during the winter following a weak (2002) monsoon. The resultant near-surface thermal inversions also have shown large differences in the life cycle and depth of occurrence between these two winters.

Response to highly active antiretroviral therapy at 6 months and long-term disease progression in HIV-1 infection.

Abstract: Objective: To compare the long-term prognostic significance of different definitions of immunologic and virologic responses to highly active antiretroviral therapy (HAART) at 6 months. Methods: This was a prospective study conducted in 68 French hospitals. HAART was initiated in 2236 protease inhibitor-naive patients included in the French Hospital Database on HIV. Multivariate Cox proportional hazard models measuring time from 6 months after starting HAART were used to compare the strength of the association between different definitions of immunologic and virologic responses at 6 months and subsequent progression to AIDS or death. The Akaike's Information Criteria were used to identify the most appropriate model. Results: During a median follow-up of 58 months, 325 patients experienced an AIDS-defining event or died. The model that fined best was the model in which the CD4 cell count and plasma HIV-1 RNA values attained at 6 months were considered. The risk of clinical progression at 5 years ranged from 7% (95% confidence interval [Cl]: 4-10) in patients whose CD4 cell count at 6 months was ≥350 cells/μL and whose HIV-1 RNA concentration was <3 log 10 copies/mL to 63% (95% CI: 52-75) in patients whose CD4 cell count at 6 months was <100 cells/μL and whose HIV-1 RNA concentration was ≥5 log 10 . Conclusions: Plasma HIV-1 RNA concentration and CD4 cell count should be taken into account independently when evaluating early response to treatment. The persistent impact of early response on clinical progression at 5 years emphasizes the major importance of the success of first-line HAART.