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[en] The incidence of varicose veins in lower limbs is increasing in the Indian subcontinent. With the advent of radiofrequency ablation (RFA), an effective minimally invasive technique is now available to treat varicose veins. RFA can be performed with either unipolar or bipolar probes. We present a simple technique for bipolar radiofrequency-induced thermotherapy of the great saphenous vein. This can be a safe and effective alternative to surgical procedures
[en] The average pulse profiles of PSR 0809 + 74 recorded simultaneously at 25, 20, and 17 MHz show positions conforming to the dispersion law, with no perceptible superdispersion delay. The dispersion measure is 5.752 + or - 0.005/cu cm pc. 9 references
[en] Scattering of mobile-phone base-stations within populated areas is a source of some misscomfortableness to many people. As there is no one agreed on safety level for the MPE for RF/MW all over the world, measurements of radiation emitted from base-stations is a necessity. In this work we screened out some mobile-phone base-stations inside and outside Khartoum city in Sudan. Measurements were done indoor and outdoor to maximum horizontal distance of about 300 m from the base of the base-stations. Results obtained were then compared to the maximum and minimum MPE values admitted in different countries in the world. The maximum MPE value (i.e- 0.57 mW/cm2) consider only the thermal effects of the RF/MW, while other values tend to reduce the exposure limits to as minimum as possible for safety considerations (considering non-thermal effects). Some of the values obtained were consistent with some reported biological effects. We recommended the removal of some base-stations from sensitive areas like schools, kindergardens, hostels, hospitals, etc. (author)
[en] Recent discoveries of dispersed, non-periodic impulsive radio signals with single-dish radio telescopes have sparked significant interest in exploring the relatively uncharted space of fast transient radio signals. Here we describe V-FASTR, an experiment to perform a blind search for fast transient radio signals using the Very Long Baseline Array (VLBA). The experiment runs entirely in a commensal mode, alongside normal VLBA observations and operations. It is made possible by the features and flexibility of the DiFX software correlator that is used to process VLBA data. Using the VLBA for this type of experiment offers significant advantages over single-dish experiments, including a larger field of view, the ability to easily distinguish local radio-frequency interference from real signals, and the possibility to localize detected events on the sky to milliarcsecond accuracy. We describe our software pipeline, which accepts short integration (∼ ms) spectrometer data from each antenna in real time during correlation and performs an incoherent dedispersion separately for each antenna, over a range of trial dispersion measures. The dedispersed data are processed by a sophisticated detector and candidate events are recorded. At the end of the correlation, small snippets of the raw data at the time of the events are stored for further analysis. We present the results of our event detection pipeline from some test observations of the pulsars B0329+54 and B0531+21 (the Crab pulsar).
[en] Acute pneumothorax is a frequent complication after percutaneous pulmonary radiofrequency (RF) ablation. In this study we present three cases showing delayed development of pneumothorax after pulmonary RF ablation in 34 patients. Our purpose is to draw attention to this delayed complication and to propose a possible approach to avoid this major complication. These three cases occurred subsequent to 44 CT-guided pulmonary RF ablation procedures (6.8%) using either internally cooled or multitined expandable RF electrodes. In two patients, the pneumothorax, being initially absent at the end of the intervention, developed without symptoms. One of these patients required chest drain placement 32 h after RF ablation, and in the second patient therapy remained conservative. In the third patient, a slight pneumothorax at the end of the intervention gradually increased and led into tension pneumothorax 5 days after ablation procedure. Underlying bronchopleural fistula along the coagulated former electrode track was diagnosed in two patients. In conclusion, delayed development of pneumothorax after pulmonary RF ablation can occur and is probably due to underlying bronchopleural fistula, potentially leading to tension pneumothorax. Patients and interventionalists should be prepared for delayed onset of this complication, and extensive track ablation following pulmonary RF ablation should be avoided.
[en] The radio source Sgr A has been mapped with the Very Large Array (VLA) at 6 and 20 cm with an angular resolution of 5'' x 8'' arc. In agreement with the earlier 'WORST' map, the non-thermal source Sgr A East shows a shell structure, while the thermal source Sgr A West shows a spiral-like morphology. The authors suggest that Sgr A East is a supernova remnant (SNR) near the galactic centre. Its surface brightness is the third largest in our galaxy after Cas A and the Crab Nebula. The diameter is 9 pc and the source fits the surface-brightness diameter relationship of Clark and Caswell (1976) if a distance of 10 kpc is assumed. (Auth.)