Observation of a uniform temperature dependence in the electrical resistance across the structural phase transition in thin film vanadium oxide (VO2VO_{2})

An electrical study of thin $VO_{2}$ films in the vicinity of the structural phase transition at $68^{0}C$ shows (a) that the electrical resistance $R$ follows $log (R)$ $\propto$ $-T$ over the $T$-range, $20 < T < 80 ^{0}C$ covering both sides of the structural transition, and (b) a history dependent hysteresis loop in $R$ upon thermal cycling. These features are attributed here to transport through a granular network.Comment: 3 pages, 3 color figure

Demonstration of a 1/4 cycle phase shift in the radiation-induced oscillatory-magnetoresistance in GaAs/AlGaAs devices

We examine the phase and the period of the radiation-induced oscillatory-magnetoresistance in GaAs/AlGaAs devices utilizing in-situ magnetic field calibration by Electron Spin Resonance of DiPhenyl-Picryl-Hydrazal. The results confirm a $f$-independent 1/4 cycle phase shift with respect to the $hf = j\hbar\omega_{c}$ condition for $j \geq 1$, and they also suggest a small ($\approx$ 2%) reduction in the effective mass ratio, $m^{*}/m$, with respect to the standard value for GaAs/AlGaAs devices.Comment: 4 pages, 4 color figure

Injection ranitidine induced death

Ranitidine is a histamine-2-receptor antagonist. It was a commonly used drug. It holds excellent safety record. Anaphylactic reactions to ranitidine is uncommonly encountered. Death due to ranitidine is extremely a rare event and very few cases are reported world-wide. Clinical history, Lab investigations and histological data of a 43-Years old woman with negative history of allergic events, who died suddenly after the intra-venous administration of 50mg of intravenous ranitidine which was prescribed as a routine pre medication prior hysterectomy is presented below. Though the incidence of anaphylactic reactions is less with ranitidine, precautions to be taken prior administration of the drug and when such an event is encountered it should be promptly managed

Radiopharmaceuticals Pattern of Development and Utilisation in India

The availability of research reactors at an early stage of our Atomic Energy Programme led to developmental efforts in the field of radiopharmaceuticals. Starting with temporary laboratories for this work, a sophisticated and dedicated Radiopharmaceutical Laboratory is now installed at Vashi in New Bombay. The use of several /sup 125/I-labelled compounds like Rose-Bengal, hippuran, etc. for imaging has been replaced over the years by /sup 99m/Tc compounds; the final formulations are prepared at the hospital using generators and cold kits supplied by the Board of Radioisotope Technology. Parallel with the development of short lived generators in radiopharmaceuticals came advances in imaging and instrumentation techniques, the scanners being replaced by sophisticated gamma cameras, with capabilities for tomography and computerisation. About 40 centres in India have the modern instrumentation and equipment needed for carrying out nuclear medicine procedures. Further growth of nuclear medicine centres in the country has, however, been limited by the need to import such advanced high cost instrumentation not currently available from indigenous sources. Regarding in-vitro radiopharmaceuticals, some RIA and IRMA kits and procedures have been developed. These include assay of T/sub 3/, T/sub 4/ and TSH in the thyroid group of hormones. Kits for several other important procedures are still being imported by some large medical centres. There are over a hundred and fifty medical laboratories carrying out RIA procedures

Phase study of oscillatory resistances in microwave-irradiated- and dark- GaAs/AlGaAs devices: Indications of a new class of integral quantum Hall effect

We report the experimental results from a dark study and a photo-excited study of the high mobility GaAs/AlGaAs system at large filling factors, $\nu$. At large-$\nu$, the dark study indicates several distinct phase relations ("Type-1", "Type-2", and "Type-3") between the oscillatory diagonal- and Hall- resistances, as the canonical Integral Quantum Hall Effect (IQHE) is manifested in the "Type-1" case of approximately orthogonal diagonal- and Hall resistance- oscillations. Surprisingly, the investigation indicates quantum Hall plateaus also in the "Type-3" case characterized by approximately "anti-phase" Hall- and diagonal- resistance oscillations, suggesting a new class of IQHE. Transport studies under microwave photo-excitation exhibit radiation-induced magneto-resistance oscillations in both the diagonal, $R_{xx}$, and off-diagonal, $R_{xy}$, resistances. Further, when the radiation-induced magneto-resistance oscillations extend into the quantum Hall regime, there occurs a radiation-induced non-monotonic variation in the amplitude of Shubnikov-de Haas (SdH) oscillations in $R_{xx}$ \textit{vs}. B, and a non-monotonic variation in the width of the quantum Hall plateaus in $R_{xy}$. The latter effect leads into the vanishing of IQHE at the minima of the radiation-induced $R_{xx}$ oscillations with increased photo-excitation. We reason that the mechanism which is responsible for producing the non-monotonic variation in the amplitude of SdH oscillations in $R_{xx}$ under photo-excitation is also responsible for eliminating, under photo-excitation, the novel "Type-3" IQHE in the high mobility specimen.Comment: 11 pages, 12 color figure