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PEO/PVDF–HFP [poly(ethylene oxide)/poly(vinylidene fluoride-co-hexafluoropropylene)] solid polymer electrolyte blend incorporating varying weights of LiTFSI [lithium bis (trifluoromethane) sulfonimide] salt was prepared. The blend with 20 wt.% of salt that exhibits maximum ionic conductivity was subjected to microstructural modification by exposing to low-energy ions of oxygen at different fluences. The ionic conductivity of the system increases by one order in magnitude when subjected to oxygen ion irradiation. The dielectric loss tangent curves are used to extract ions relaxation time. The relaxation time τ of the system is reduced from 1.42 to 0.71 μs upon irradiation which indicates enhanced segmental motion due to a rise in amorphous region in polymer matrix. The ion activation energy in the system decreases to 0.041 eV from 0.063 eV. Dielectric studies suggest an increase in dipoles in the irradiated systems possibly due to polymer chain scission in the matrix. The increase in disordered phase by ion irradiation is supported by change in crystallinity from 24% for the unirradiated systems to about 14% for the irradiated systems by X-ray diffraction and differential scanning calorimetry analysis. The shift in prominent peaks observed in Fourier transform infrared spectroscopy suggests possible scission of the polymer chains. [ABSTRACT FROM AUTHOR]

Chikungunya fever is self-limiting. However, neurological and hemorrhagic complications have been seen in recent outbreaks. The clinical manifestations of this disease are similar to those of dengue virus infection, indicating the need for differential diagnosis in areas such as India, which are endemic for both viruses. The aim of the present study was to develop monoclonal antibodies (MAbs) against Chikungunya virus (CHIKV) and assess their use in MAb-based IgM capture ELISA (MAC ELISA). The ELISA detects CHIKV-specific IgM antibodies, a marker of recent infection, in a patient's serum. One IgG1 and two IgM isotype hybrids were obtained. All of the subclones derived from the IgG1 hybrid recognized the C protein of CHIKV. The anti-C MAb ClVE4/D9 was the most promising as a detector antibody in MAC ELISA (C-MAb ELISA) yielding higher positive-to-negative (P/N) ratios. When compared with the CHIKV MAC ELISA kit developed by the National Institute of Virology (NIV), Pune (NIV MAC ELISA), the sensitivity of the test was 87.01 % with 100 % specificity. The positive and negative predictive values (PPV and NPV) were 100 % and 94.47 %, respectively. In precision testing, standard deviation (SD) and coefficient of variation (% CV) values of the C-MAb ELISA were within acceptable limits. The C-MAb ELISA detected anti-CHIKV IgM in serum of patients up to five months after the onset of infection, indicating that anti-C MAbs have strong potential for use in MAC ELISA to detect recent CHIKV infection. [ABSTRACT FROM AUTHOR]

Abstract: Numerical simulation of reciprocating compressors is important for the design, development, improvement and optimization of the elements constituting the compressor circuit. In this work, an object-oriented unstructured modular numerical simulation of reciprocating compressors is presented. Pressure correction approach is applied for the resolution of tubes, chambers and compression chambers, while valve dynamics are modelled assuming a spring-mass system having single degree of freedom. The modular approach offers advantages of handling complex circuitry (e.g. parallel paths, multiple compressor chambers, etc.), coupling different simulation models for each element and adaptability to different configurations without changing the program. The code has been verified with some basic tests for assuring asymptotic behaviour to guarantee error free code and physically realistic results. Cases with different compressor configurations and working fluids (R134a, R600a and R744) have also been worked out. Numerical results are compared with experimental data and illustrative cases of multi-stage compression are also presented. [Copyright &y& Elsevier]

We have prepared, characterized and investigated a new PEG-2000 based solid polymer electrolyte (PEG)xNH4I. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265{330 K. Selected compositions of the electrolyte were exposed to a beam of 8 MeV electrons to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples were also quenched at liquid nitrogen temperature and conductivity measurements were made. The ionic conductivity at room temperature exhibits a characteristic double peak for the composition x = 20 and 70. Both electron beam irradiation and quenching at low temperature have resulted in an increase in conductivity by 1-2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and proton NMR measurements also support this conclusion. [ABSTRACT FROM AUTHOR]

We have prepared, characterized and investigated a new PEG-2000 based solid polymer electrolyte (PEG)x: NH4NO3. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265-330 K. Selected compositions of the electrolyte are exposed to a beam of 8 MeV electrons and 60Co γ-rays to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, x = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2-3. Exposure to γ-rays enhances the conductivity by one order of magnitude. Quenching at low temperature has resulted in an increase in conductivity by 1-2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and NMR measurements also support this conclusion. [ABSTRACT FROM AUTHOR]

Abstract: (CH3)4NPF6 is studied by NMR measurements to understand the internal motions and cross relaxation mechanism between the heterogeneous nuclei. The spin lattice relaxation times (T 1) are measured for 1H and 19F nuclei, at three (11.4, 16.1 and 21.34MHz) Larmor frequencies in the temperature range 350–50K and 1H NMR second moment measurements at 7MHz in the temperature range 300–100K employing home made pulsed and wide-line NMR spectrometers. 1H NMR results are attributed to the simultaneous reorientations of both methyl and tetramethylammonium groups and motional parameters are evaluated. 19F NMR results are attributed to cross relaxation between proton and fluorine and motional parameters for the PF6 group reorientation are evaluated. [Copyright &y& Elsevier]

This paper describes the effect of 24 MeV proton irradiation on the electrical characteristics of a pnp bipolar junction transistor 2N 2905A. I-V , C-V and DLTS mea- surements are carried out to characterize the transistor before and after irradiation. The properties of deep level defects observed in the bulk of the transistor are investigated by analysing the DLTS data. Two minority carrier levels, EC - 0.27 eV and EC - 0.58 eV and one majority carrier level, EV + 0:18 eV are observed in the base collector junction of the transistor. The irradiated transistor is subjected to isochronal annealing. The influence of isochronal annealing on I-V , C-V and DLTS characteristics are monitored. Most of the deep level defects seem to anneal out above 400°C. It appears that the deep level defects generated in the bulk of the transistor lead to transistor gain degradation. A comparison of proton- and electron-induced gain degradation is made to assess the vulnerability of pnp transistor as against npn transistors. [ABSTRACT FROM AUTHOR]

Dielectric and conductivity behaviors of nano ZnO doped polyvinyl alcohol (PVA) composites for various concentrations of dopant were investigated using impedance spectroscopy for a wide range of temperatures (303 K-423 K) and frequencies (5 Hz-30MHZ). The dielectric properties of host polymer matrix have been improved by the addition of nano ZnO and are found to be highly temperature dependent. Anomalous dielectric behavior was observed in the frequency range of 2.5 MHz-5 MHz. Increase in dielectric permittivity and dielectric loss was observed with respect to temperature. The Cole-Cole plot could be modeled by low resistance regions in a high resistance matrix and the lowest resistance was observed for the 10 mol. % films. The imaginary part of the electric modulus showed asymmetric peaks with the relaxation following Debye nature below and non-Debye nature above the peaks. The ac conductivity is found to obey Jonscher's power law, whereas the variation of dc conductivity with temperature was found to follow Arrhenius behavior. Two different activation energy values were obtained from Arrhenius plot indicating that two conduction mechanisms are involved in the composite films. Fitting the ac conductivity data to Jonscher's law indicates that large polaron assisted tunneling is the most likely conduction mechanism in the composites. Maximum conductivity is observed at 423K for all the samples and it is optimum for 10mol. % ZnO doped PVA composite film. Significant increase in dc and ac conductivities in these composite films makes them a potential candidate for application in electronic devices. [ABSTRACT FROM AUTHOR]

Abstract The structural and magnetic properties of Al substituted yttrium-iron garnet (Y 3 Al x Fe 5-x O 12 , x = 0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6 and 1.8) ceramic powders synthesized using solution combustion method were investigated. Post combustion, the samples were calcination at 1045 °C for 6 h and subsequently at 1200 °C for 6 h to obtain phase-pure garnets. X-ray diffraction (XRD) results confirm the formation of garnets with Ia 3 ¯ d structure. The occupancy of Y3+ ions in the dodecahedral site and the distribution of Al3+ and Fe3+ ions in the tetrahedral and octahedral sites in the bcc structure of the garnet were confirmed by Rietveld refinement of XRD patterns, Mössbauer spectroscopy and 57Fe internal field NMR spectroscopy. For low Al content, Al3+ ions have preference to occupy tetrahedral (T d) sites than the octahedral (O h) sites. At higher Al content the distribution of Al tends towards a ratio of 3:2 at the tetrahedral:octahedral site. Increase in Al doping results in the decrease in the lattice parameter due to smaller size of Al3+ as compared to Fe3+ ion. All the studied samples show coral-network-like surface morphology. The saturation magnetization (M S) values decrease from ∼26.94 emu/g to ∼ 0.17 emu/g with increase in Al content from 0.0 to 1.8. Further addition of Al makes the sample paramagnetic at RT. Substitution of non-magnetic Al3+ reduces the saturation magnetization rapidly due to the decrease in the superexchange interaction in the crystal. Highlights • Yttrium-aluminium-iron garnet powders were synthesized via solution combustion method. • Al-doping reduces lattice parameter and magnetism due to the smaller ionic radii of Al3+. • For small Al-concentration, Al prefers to occupy tetrahedral site than octahedral site of YIG. • Preference of Al3+ to go tetrahedral site is due to the smaller ionic radius of Al3+. • Internal field NMR intensity decreases rapidly followed by a slow decrease as Al content increases. [ABSTRACT FROM AUTHOR]

We report the internal field nuclear magnetic resonance (IFNMR) and Mössbauer spectroscopy study of Li-Zn ferrites at RT. The results were supported by the IFNMR data measured at 77 K. As Zn concentration increases the IFNMR echo amplitude decreases and below certain Zn concentration no signal was detected. At RT the echo amplitude vanishes at a lower Zn concentration, whereas at 77 K, the echo amplitude does not vanish completely (except for pure Zn-ferrite). However, in Mössbauer spectroscopy at RT, we have observed magnetically ordered state of all the Li-Zn ferrite samples. This discrepancy could be related to the difference between the time scale of detection of the spins by Mössbauer spectroscopy (10 −7 –10 −10  s) and NMR spectroscopy (10 −6  s). Hence, sensitivity of zero-field NMR depends on the magnetic hyperfine field, temperature and abundance of the magnetic cations at the lattice of the spinel ferrites. We have demonstrated that the ‘two-equal-pulses’ sequence leads to higher echo signal than the spin echo pulse sequence due to the presence of distribution of internal magnetic fields throughout the material. We obtained a limiting value for the fraction of spins needed to produce an echo signal at a particular temperature and at a particular site of the Li-Zn ferrite spinels that can be sensitively detected by pulsed IFNMR technique. [ABSTRACT FROM AUTHOR]

Papillary poroid hidradenoma is a very rare entity which belongs to poroid neoplasms, which represents 10% of sudoriferous tumours. It can be easily misdiagnosed as a malignant neoplasm. A 34-years-old male presented with an asymptomatic mass over the right chest wall, below the nipple, of 18 months duration. Clinical examination revealed tense cystic swelling which revealed hypoechoic and solid components on imaging. Clinically, a malignancy was suspected and a surgical excision was done. Histology and immunoreactivity to pan cytokeratin, epithelial membrane antigen and carcino- embryonic antigen confirmed the diagnosis. We are reporting this case because of the rarity of its presentation [ABSTRACT FROM AUTHOR]

Highlights: [•] CaSiO3:Pr3+ was prepared by facile low temperature solution combustion method. [•] The crystalline phase of the product is obtained by adopting sintering method. [•] Samples prepared at 500°C and calcined at 900°C for 3h showed β-phase. [•] The Pr3+ doped CaSiO3 shows “unusual results”. [•] The electrical microstructure has been accepted to be of internal barrier layer capacitor. [ABSTRACT FROM AUTHOR]

Abstract: Nano-ceramic phosphor CaSiO3 doped with Pb and Mn was synthesized by the low temperature solution combustion method. The materials were characterized by Powder X-Ray Diffraction (XRD), Thermo–gravimetric and Differential Thermal Analysis (TG–DTA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The Electron Paramagnetic Resonance (EPR) spectrum of the investigated sample exhibits a broad resonance signal centered at g=1.994. The number of spins participating in resonance (N) and its paramagnetic susceptibility (χ) have been evaluated. Photoluminescence of doped CaSiO3 was investigated when excited by UV radiation of 256nm. The phosphor exhibits an emission peak at 353nm in the UV range due to Pb2+. Further, a broad emission peak in the visible range 550–625nm can be attributed to 4T1→6A1 transition of Mn2+ ions. The investigation reveals that doping perovskite nano-ceramics with transition metal ions leads to excellent phosphor materials for potential applications. [Copyright &y& Elsevier]

This paper describes the fabrication of MOS capacitor and DLTS study of annihilation of deeplevel defects upon thermal annealing. Ni/SiO/ n-Si MOS structures fabricated on n-type Si wafers were investigated for process-induced deep-level defects. The deep-level traps in Si substrates induced during the processing of Ni/SiO/ n-Si have been investigated using deep-level transient spectroscopy (DLTS). A characteristic deep-level defect at E = 0·49 eV which was introduced during high-temperature thermal oxidation process was detected. The trap position was found to shift to different energy levels ( E = 0·43, 0·46 and 0·34 eV) during thermal annealing process. The deep-level trap completely anneals at 350°C. Significant reduction in trap density with an increase in recombination life time and substrate doping concentration as a function of isochronal annealing were observed. [ABSTRACT FROM AUTHOR]

Ni/SiO2/Si MOS structures were fabricated on n-type Si wafers and were irradiated with 50 MeV Li3+ ions with fluences ranging from 1×1010 to 1×1012 ions/cm2. High frequency C-V characteristics are studied in situ to estimate the build-up of fixed and oxide charges. The nature of the charge build-up with ion fluence is analyzed. Defect levels in bulk Si and its properties such as activation energy, capture cross-section, trap concentration and carrier lifetimes are studied using deep-level transient spectroscopy. Electron traps with energies ranging from 0.069 to 0.523 eV are observed in Li ion-irradiated devices. The dependence of series resistance, substrate doping and accumulation capacitance on Li ion fluence are clearly explained. The study of dielectric properties (tan δ and quality factor) confirms the degradation of the oxide layer to a greater extent due to ion irradiation. [ABSTRACT FROM AUTHOR]

Nanocrystalline porous CaSiO3 ceramic powders have been synthesized by a novel low-temperature initiated self-propagating, gas-producing solution combustion method. Single phase β-CaSiO3 (Wollastonite) is formed by calcination at 900°C for 3h. The crystallization and phase formation temperatures in this method are found to be lower compared to the powder obtained via solid state reaction method. The powder is characterized by powder XRD (X-Ray Diffraction), and crystallite sizes are evaluated using Scherrer's formula as well as from TEM (Transmission Electron Microscopy). The Wollastonite powder is exposed to 60Co γ-radiation to accumulated doses of 1, 3, and 5 KGγ and low-frequency (10²-106 Hz) dielectric measurements are carried out before and after irradiation. The dielectric conductivity is estimated from the dielectric constant and loss tangent. Exposure to γ- radiation results in substantial modification in the properties of the ceramic powder due to changes in the porosity of the material. The correlation between dielectric and conductivity properties is discussed in relation to porosity effect. [ABSTRACT FROM AUTHOR]

A commercial bipolar junction transistor (2N 2219A, npn) irradiated with 84 MeV O6+-ions with fluence of the order of 1013 ions cm-2 is studied for radiation-induced gain degradation and deep-level defects or recombination centers. I-V measurements are made to study the gain degradation as a function of ion fluence. Properties such as activation energy, trap concentration and capture cross section of deep levels are studied by deep-level transient spectroscopy. Minority carrier trap energy levels with energies ranging from EC -0.17 eV to EC -0.55 eV are observed in the base-collector junction of the transistor. Majority carrier defect levels are also observed with energies ranging from EV +0.26 eV to EV +0.44 eV. The irradiated device is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 250 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for an increase in base current through Shockley-Read-Hall or multi-phonon recombination and consequent transistor gain degradation. [ABSTRACT FROM AUTHOR]

Abstract: Commercial bipolar junction transistor (2N 2219A, npn) irradiated with 150MeV Cu11+-ions with fluence of the order 1012 ionscm−2, is studied for radiation induced gain degradation and deep level defects. I–V measurements are made to study the gain degradation as a function of ion fluence. The properties such as activation energy, trap concentration and capture cross-section of deep levels are studied by deep level transient spectroscopy (DLTS). Minority carrier trap levels with energies ranging from E C −0.164eV to E C −0.695eV are observed in the base–collector junction of the transistor. Majority carrier trap levels are also observed with energies ranging from E V +0.203eV to E V +0.526eV. The irradiated transistor is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 350°C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for transistor gain degradation. [Copyright &y& Elsevier]

Abstract: 1H NMR spin–lattice relaxation time measurements have been carried out in [(CH3)4N]2SeO4 in the temperature range 389–6.6K to understand the possible phase transitions, internal motions and quantum rotational tunneling. A broad T 1 minimum observed around 280K is attributed to the simultaneous motions of CH3 and (CH3)4N groups. Magnetization recovery is found to be stretched exponential below 72K with varying stretched exponent. Low-temperature T 1 behavior is interpreted in terms of methyl groups undergoing quantum rotational tunneling. [Copyright &y& Elsevier]

Abstract: Commercial npn transistor (2N 2219A) irradiated with 50MeV Li3+-ions with fluences ranging from 3.1×1013 ionscm−2 to 12.5×1013 ionscm−2, is studied for radiation induced gain degradation and minority carrier trap levels or recombination centers. The properties such as activation energy, trap concentration and capture cross section of induced deep levels are studied by deep level transient spectroscopy (DLTS) technique. Minority carrier trap levels with energies ranging from 0.237eV to 0.591eV were observed in the base–collector junction of the transistor. In situ I–V measurements were made to study the gain degradation as a function of ion fluence. Ion induced energy levels result in increase in the base current through Shockley Read Hall (SRH) or multi-phonon recombination and subsequent transistor gain degradation. [Copyright &y& Elsevier]

Abstract: This paper describes the effect of 8MeV electron beam on the forward current gain of space borne commercial indigenous bipolar junction transistors 2N2219A (npn), 2N3019 (npn) and 2N2905A (pnp). The devices are exposed to 8MeV electron in the biased condition. The collector characteristics and Gummel plots are obtained as a function of accumulated dose. An excess base current model as well as Messenger–Spratt equation have been used to account for the observed gain degradation. The results indicate that 8MeV electrons of high dose rate induce gain degradation by increasing the base current as well as decrease in collector current. The current gain degradation appears to be predominantly due to displacement damage in the bulk of the transistor. Off-line measurements of the h FE of the irradiated transistors indicate that the displacement induced defect and recombination centers do not anneal even at 150°C. [Copyright &y& Elsevier]

This article presents the theoretical calculation of the variation of displacement damage factors as a function of energy and rad equivalent fluence in bipolar junction transistor for various particulate radiation viz ., He, Si, Cl, Ti, Ni, Br, Ag, I, and Au. The calculation is based on the experimental data on γ-ray induced gain degradation in a commercial space borne BJT (2N3019). The method involves the calculation of γ-ray dose (rad(Si)) equivalent of effective particle fluence. The linear energy transfer (LET) in silicon for different particle radiation obtained from TRIM calculation has been used for the conversion of γ-dose into fluence of various particles. The estimation predicts a smooth increase in the displacement damage factor as the mass of the ion increases. Further, the displacement damage factor reaches a maximum at the same value of energy, which corresponds to maximum LET for all heavy ions. The maximum value of damage factor marginally decreases with increasing ion fluence for an ion of given energy. The results are compared with the data available in the literature for proton, deuteron, and helium induced displacement damage. [ABSTRACT FROM AUTHOR]

This paper describes the results of the effect of 24 MeV proton and [sup60]Co γ-irradiation on the collector characteristics and forward current gain of commercial bipolar transistor (npn 2N2219A). The transistor has been exposed to these radiations in the biased condition and the collector characteristics and forward current gain have been measured as a function of proton fluence and γ-dose. The observation is that both the proton and γ-irradiation induce significant gain degradation in the transistor. The results are discussed in terms of displacement damage produced by energetic protons and γ-radiation in the bulk of the semiconductor. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy and toxicity of moricizine in treating patients with serious ventricular arrhythmias and inducible sustained ventricular tachycardia.Design: Uncontrolled clinical trial.Setting: The intensive care and telemetry units of Northwestern Memorial Hospital, St. Francis Hospital and Medical Center, and Lenox Hill Hospital.Patients: Twenty-six patients with sustained ventricular arrhythmias or hemodynamically significant nonsustained ventricular tachycardia, most of whom failed therapy with at least one class I antiarrhythmic agent.Intervention: Patients were treated with moricizine, 400 to 1000 mg/d.Measurement: Efficacy was assessed by the results of programmed ventricular stimulation done during moricizine therapy.Main Results: Seven of the 26 patients (27%) developed life-threatening ventricular proarrhythmia during moricizine loading. Three patients had incessant sustained ventricular tachycardia, two had incessant nonsustained ventricular tachycardia, one had new sustained ventricular tachycardia, and one had new cardiac arrest. One of these patients died of intractable ventricular fibrillation. No clinical or electrophysiologic variables clearly identified those at risk for proarrhythmia. Only 3 of 26 patients (12%) became noninducible on moricizine.Conclusion: Moricizine has a low rate of efficacy and carries a considerable risk for life-threatening proarrhythmia in patients with serious ventricular arrhythmias and inducible ventricular tachycardia who have failed therapy with other class I antiarrhythmic agents. [ABSTRACT FROM AUTHOR]

Flux variability is one of the defining characteristics of Seyfert galaxies, a class of active galactic nuclei (AGN). Although these variations are observed over a wide range of wavelengths, results on their flux variability characteristics in the ultraviolet (UV) band are very limited. We present here the long-term UV flux variability characteristics of a sample of fourteen Seyfert galaxies using data from the International Ultraviolet Explorer acquired between 1978 and 1995. We found that all the sources showed flux variations with no statistically significant differences in the amplitude of UV flux variation between shorter and longer wavelengths. Also, the flux variations between different near-UV (NUV, 1850-3300 Å) and far-UV (FUV, 1150-2000 Å) passbands in the rest frames of the objects are correlated with no time lag. The data show indications of (i) a mild negative correlation of UV variability with bolometric luminosity and (ii) weak positive correlation between UV variability and black hole mass. At FUV, about 50% of the sources show a strong correlation between spectral indices and flux variations with a hardening when brightening behaviour, while for the remaining sources the correlation is moderate. In NUV, the sources do show a harder spectrum when brighter, but the correlation is either weak or moderate. [ABSTRACT FROM AUTHOR]