In Kerala, south-western India, five patients developed systemic envenoming after bites by hump-nosed pit vipers (
Hypnale hypnale), proved by identification of the snakes responsible. Two of the ...dead snakes had been misidentified as saw-scaled vipers (
Echis carinatus), while three had remained unidentified. Symptoms of local envenoming were pain, swelling, haemorrhagic blistering, bruising and regional lymphadenopathy. Systemic symptoms included headache, nausea, vomiting and abdominal and chest pain. There was evidence of haemostatic dysfunction (coagulopathy, fibrinolysis, thrombocytopenia or spontaneous systemic haemorrhage) in all cases and of microangiopathic haemolysis in two. Two patients were haemodialysed for acute renal failure, one of whom developed pulmonary oedema requiring mechanical ventilation. In India,
H. hypnale has not previously been regarded as a cause of frequent or potentially dangerous envenoming. Its medical importance has been overlooked throughout its geographical range, probably because of confusion with other small species. No specific antivenom exists, yet most patients are treated with non-specific antivenoms, risking reactions without hope of benefit. An effective antivenom is urgently needed in south India and in Sri Lanka, where this species is also a common cause of bites.
Commercially available α-Al2O3:C powder was studied for deep energy level defects by a newly suggested method using thermally assisted optically stimulated luminescence (TA-OSL) phenomenon. The ...method involves simultaneous application of continuous wave optically stimulated luminescence (CW-OSL) as well as thermal stimulation up to 400 °C, using a linear heating rate of 4 K/s. By using this method, two well-defined peaks at 121 °C and 232 °C were observed. These TA-OSL peaks have been correlated to two different types of deeper defects which can be bleached at 650 °C and 900 °C respectively on thermal treatment. These deeper defects, having larger thermal trap depth and relatively lower photoionization cross-section at room temperature for stimulation with blue LED (470 nm), are stable up to 500 °C, so they can store absorbed dose information even if the sample is inadvertently exposed to light or temperature. As only a fraction of signal is bleached during TA-OSL readout, multiple readouts could be performed on an exposed sample using this technique. The dose vs TA-OSL response from deep traps of α-Al2O3:C was found to be linear up to 10 kGy, thus extending its application for high dose dosimetry. The value of thermally assisted energy (EA) associated with these traps in α-Al2O3:C has been determined to be 0.268 eV and 0.485 eV respectively and the corresponding values of photoionization cross-section at room temperature (25 °C), for optical stimulation with blue light (470 nm), are 5.82 × 10−20 and 3.70 × 10−22 cm2, respectively. The process of thermally assisted OSL has been formulated analytically as well as theoretically for describing the temperature dependence of optical cross-section and evaluation of thermally assisted energy associated with deep traps.
► A novel method of measuring the signal from deeper traps in Al2O3:C for its use in high dose dosimetry. ► Mathematical formulation of TA-OSL phenomenon. ► Extended dose linearity of Al2O3:C phosphor up to 10 kGy using TA-OSL of deeper traps, with choice of multiple readouts. ► Discusses about the nature of deep traps in Al2O3:C. ► Determination of thermally assisted energy associated with the deeper traps and corresponding photoionization cross-section.
Al-doped Co-Cd ferrites Co
0.4
Cd
0.6
Al
x
Fe
2–
x
O
4
(
x
= 0.1, 0.2, 0.3, 0.4) were prepared by solution-combustion synthesis (SCS) and characterized by XRD, SEM, EDAX, and FTIR. A simple cubic ...spinel structure of synthesized ferrites with
a
= 8.496–8.545 Å was confirmed by XRD. The uniform size distribution of ferrite grains was observed in SEM micrographs. The elemental analysis confirmed the presence of all metal ions from the ferrite formula. FTIR spectra showed two absorption bands, υ
1
(568–580 cm
–1
) and υ
2
(413–451cm
–1
), attributed to Me–O vibration modes at tetrahedral and octahedral sites, respectively. Our results may turn interesting to those engaged in combustion synthesis of ferrites.
In this paper, a volume integral equation (VIE)-based modeling method suitable for a patch or slot antenna on a thin finite dielectric substrate is developed and tested. Two new key features of the ...method are the use of proper dielectric basis functions and proper VIE conditioning, close to the metal surface, where the surface boundary condition of the zero tangential E -component must be extended into adjacent tetrahedra. The extended boundary condition is the exact result for the piecewise-constant dielectric basis functions. The latter operation allows one to achieve a good accuracy with one layer of tetrahedra for a thin dielectric substrate and thereby greatly reduces computational cost. The use of low-order basis functions also implies the use of low-order integration schemes and faster filling of the impedance matrix. For some common patch/slot antennas, the VIE-based modeling approach is found to give an error of about 1% or less in the resonant frequency for one-layer tetrahedral meshes with a relatively small number of unknowns. This error is obtained by comparison with fine finite-element method (FEM) simulations, or with measurements, or with the analytical mode matching approach. Hence it is competitive with both the method of moments surface integral equation approach and with the FEM approach for the printed antennas on thin dielectric substrates.
Multi-scale tracer and full-chemistry simulations with the STEM atmospheric chemistry model are used to analyze the effects of transported background ozone (O3) from the eastern Pacific on California ...air quality during the ARCTAS-CARB experiment conducted in June, 2008. Previous work has focused on the importance of long-range transport of O3 to North America air quality in springtime. However during this summer experiment the long-range transport of O3 is also shown to be important. Simulated and observed O3 transport patterns from the coast to inland northern California are shown to vary based on meteorological conditions and the O3 profiles over the oceans, which are strongly episodically affected by Asian inflows. Analysis of the correlations of O3 at various altitudes above the coastal site at Trinidad Head and at a downwind surface site in northern California, show that under long-range transport events, high O3 air-masses (O3>60 ppb) at altitudes between about 2 and 4 km can be transported inland and can significantly influence surface O3 20–30 h later. These results show the importance of characterizing the vertical structure of the lateral boundary conditions (LBC) needed in air quality simulations. The importance of the LBC on O3 prediction during this period is further studied through a series of sensitivity studies using different forms of LBC. It is shown that the use of the LBC downscaled from RAQMS global model that assimilated MLS and OMI data improves the model performance. We also show that the predictions can be further improved through the use of LBC based on NASA DC-8 airborne observations during the ARCTAS-CARB experiment. These results indicate the need to develop observational strategies to provide information on the three-dimensional nature of pollutant distributions, in order to improve our capability to predict pollution levels and to better quantify the influence of these Asian inflows on the US west coast air quality.
Measurements of the local susceptibility and 3d spin relaxation rate for single Fe impurities embedded in a nanocrystalline Nb host indicates the emergence of a local moment on Fe at and below a ...critical size of 11 nm. Our ab initio electronic structure calculations show that the moment formation occurs due to Stoner enhancement arising from a size dependent lattice expansion and a consequent shift in the Fermi level. We also show that a size-induced positive host spin polarization of the Nb-4d band electrons strongly influences the fluctuation rate of the Fe moment.
There has been rapid progress in exploring microorganisms for green synthesis of nanoparticles since microbes show extraordinary diversity in terms of species richness and niche localization. ...Microorganisms are easy to culture using relatively inexpensive and simple nutrients under varied conditions of temperature, pressure, pH, etc. In this work, Deinococcus radiodurans that possesses the ability to withstand extremely high radiation and desiccation stress has been employed for the synthesis of silver nanoparticles (AgNPs). D. radiodurans was able to accumulate AgNPs in medium under various conditions, and process optimization was carried out with respect to time, temperature, pH, and concentration of silver salt. AgNPs were characterized using UV/vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The microbially synthesized AgNPs exhibited good antimicrobial activity against both Gram-negative and Gram-positive organisms and anti-biofouling activity. Their ability to inhibit growth and proliferation of cancer cell line was also examined, and it could be seen that AgNPs synthesized using D. radiodurans exhibited excellent anticancer activity.
The lithium (Li) and potassium (K) salts of 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4,6-trinitroanilino benzoic acid (TABA) were prepared and characterized during this work. The synthesis was carried ...out by addition of a solution of lithium/potassium hydroxide to the aqueous solution of NTO and TABA, respectively. The products were characterized by elemental analysis, metal content determination and Fourier Transform Infrared (FTIR) Spectrum. Differential scanning calorimetry (DSC) profile indicated that Li and K salts of NTO and TABA undergo exothermic decomposition in the temperature range of 257–360
°C suggesting their energetic nature. The thermo gravimetric (TG) weight loss pattern revealed loss of water for Li/K salts of NTO and TABA in the temperature range of 115–155
°C. Sensitivity results revealed that the compounds are insensitive to impact and friction (impact sensitivity—height of 50% explosion
>
170
cm and friction insensitivity up to 36
kg) stimuli despite even the parent molecule of NTO salts (NTO) being HEM in the hazard category of 1.1. The FTIR spectra of the gaseous products evolved during TGA of NTO and TABA salts indicated the release of NO
2. The formation of products such as LiNCO and KNCO was also observed in case of NTO salts, whereas that of CO
2 and NH containing products was indicated in case of TABA salts during this study. In order to assess the performance as energetic ballistic modifiers (EBMs), NTO and TABA salts were incorporated in the ammonium perchlorate-hydroxyl terminated polybutadiene (AP-HTPB) composite propellants. The potassium salts enhanced the burning rate of the propellant. The best catalytic effect was obtained with K-TABA salt, which increased the burning rate to the extent of ∼81% as well as brought down the
n-value to 0.15 (pressure 2–9
MPa).
PDF
