An asynchronous architecture for modeling intersegmental neural communication

This paper presents an asynchronous VLSI architecture for modeling the oscillatory patterns seen in segmented biological systems. The architecture emulates the intersegmental synaptic connectivity observed in these biological systems. The communications network uses address-event representation (AER), a common neuromorphic protocol for data transmission. The asynchronous circuits are synthesized using communicating hardware processes (CHP) procedures. The architecture is scalable, supports multichip communication, and operates independent of the type of silicon neuron (spiking or burst envelopes). A 16-segment prototype system was developed, tested, and implemented; data from this system are presented.     

La synthèse d’antennes à deux réflecteurs conformés à alimentation décalée

A potentially economic method for upgrading the gain of the large earth reflector antenna Cassegrain system to a gain comparable to that obtainable with a dualshaped reflector antenna system is presented herein. It involves a redesign of only the subreflector portion of a Cassegrain antenna or the introduction of a subreflector feed system for a paraboloid. A pair of offset subreflectors are synthesized which will give a controllable high gain amplitude distribution in the aperture of the large paraboloid. The synthesis method that is used is based on an approximate formulation for an offset dual shaped high gain antenna where the geometrical optics energy was scattered from a subreflector and then from a second large reflector which reflected a uniform phase distribution. In the present offset dual shaped subreflector (DSS) antenna, the second reflection is from a smaller subreflector and it scatters a spherical wave that feeds a hyperboloid or feeds a large paraboloid directly. Excellent results are shown for the approximate synthesis of the DSS.     

Fungal purulent constrictive pericarditis in a heart transplant patient

Purulent pericarditis caused by Candida species is rare and is associated with very high mortality. Immunosuppressed transplant patients are particularly susceptible to fungal infections. We report a case of Candida purulent constrictive pericarditis in an immunocompromised heart transplant patient who was treated successfully with antifungal agents, surgical drainage, and pericardiectomy.     

Cold pressurisation in pressurised heavy water reactors during accidents

The paper addresses the issue of cold pressurisation during a Non-Loss of Coolant Accident (non-LOCA) and steam line break events. Cold pressurisation is usually avoided during reactor start up from cold and shut down to cold but it has to be avoided even during accidents so that consequential failures do not occur. A non-LOCA event, such as isolation of containment on a spurious signal and two main steam line breaks have been analysed. It is observed that the transient behaviour of the system is similar in these events. This paper discusses the issue of cold pressurisation in these events.     

Transferrin is necessary and sufficient for the neural effect on growth in amphibian limb regeneration blastemas

The striking and apparent specific elevation of the activity of chitotriosidase found in plasma from patients with Gaucher disease (GD) Type 1 (Mc Kusick 230800) is considered a new diagnostic hallmark of GD and should prove useful in assessing clinical manifestations and monitoring enzyme supplementation therapy. Further data have suggested that the increased levels of chitotriosidade activity in plasma from patients with unexplained diseases may be indicative of a lysosomal storage disorder. We present here an experience of the plasmatic chitotriosidase in an Argentinean population consisting of three groups: a) 25 healthy controls; b) subjects related with GD: 3 patients Type 1, 3 obligated heterocygotes and 1 patient with an atypical variant of GD; c) 42 patients with a precise nosologycal definition of inherited error of metabolism (IEM) and 5 patients presumably affected by a lysosomal pathology but without enzymatic confirmation. Methylumbellypheryl-tri-N-acetyl chitotrioside hydrolase activity was markedly increased: the mean activity being > 600 times and > 100 times the mean value in plasma of our healthy control (mean 17 nmol/min/ml, range 6-60.4 nmol/min/ml) in the plasma of the patients of Gaucher Type 1 disease and an atypical variant of GD, respectively. In the two more affected patients the elevated levels of chitotriosidase activity ran parallel to the severity of the disease and also as a response to the supplementation enzymatic therapy with a decrease of 50% of its activity at 10 months of therapy at a dose of 30 u/kg/month. Moreover, no increase of chitotriosidase activity was found in the 3 obligated heterozygotes of Gaucher Type 1 and Type 2 disease or in any other of the IEM. Chitotriosidase activity was absent in plasma of 2 control subjects and in 4 patients with exact diagnosis of an IEM. The physiological role of the human chitinase still has to be established and warrants further investigation and the natural consequence of the high frequency of a genetic deficiency in man. Meanwhile, reports on the purification and characterization of human chitotriosidase with chitinolytic activity toward chitin-containing pathogens and on the cloning of cDNA encoding chitinase will be crucial to obtain a better insight into this new chapter of medical genetics.     

Phosphorylation of myosin regulatory light chain eliminates force-dependent changes in relaxation rates in skeletal muscle

The rate of relaxation from steady-state force in rabbit psoas fiber bundles was examined before and after phosphorylation of myosin regulatory light chain (RLC). Relaxation was initiated using diazo-2, a photolabile Ca2+ chelator that has low Ca2+ binding affinity (K(Ca) = 4.5 x 10(5) M(-1)) before photolysis and high affinity (K(Ca) = 1.3 x 10(7) M(-1)) after photolysis. Before phosphorylating RLC, the half-times for relaxation initiated from 0.27 +/- 0.02, 0.51 +/- 0.03, and 0.61 +/- 0.03 Po were 90 +/- 6, 140 +/- 6, and 182 +/- 9 ms, respectively. After phosphorylation of RLC, the half-times for relaxation from 0.36 +/- 0.03 Po, 0.59 +/- 0.03 Po, and 0.65 +/- 0.02 Po were 197 +/- 35 ms, 184 +/- 35 ms, and 179 +/- 22 ms. This slowing of relaxation rates from steady-state forces less than 0.50 Po was also observed when bundles of fibers were bathed with N-ethylmaleimide-modified myosin S-1, a strongly binding cross-bridge derivative of S1. These results suggest that phosphorylation of RLC slows relaxation, most likely by slowing the apparent rate of transition of cross-bridges from strongly bound (force-generating) to weakly bound (non-force-generating) states, and reduces or eliminates Ca2+ and cross-bridge activation-dependent changes in relaxation rates.     

A gene essential to brain growth and development maps to the distal arm of rat chromosome 12

Studies were undertaken to determine the stability of nitrobenzodiazepines and their 7-amino metabolites in water and blood. At 22 degrees C nitrazepam and clonazepam were stable in sterile fresh blood containing preservative over 28 days, whereas 25% of flunitrazepam was degraded. At 37 degrees C all three drugs were substantially lost over 9 h (29-51%). There was only a small loss observed for the 7-amino metabolites and no substantial amounts of parent drug and 7-amino metabolite were degraded in water under these conditions. In the absence of preservative substantial amounts (25-50%) of parent drugs were lost in fresh blood over 10 days at 22 degrees C. In bacterially-contaminated postmortem blood all three drugs were completely degraded over 8 h at 22 degrees C with almost all drug completely converted to the respective 7-amino metabolite. These metabolites were also partially degraded (10-20%) over 45 h at 22 degrees C. All 3 nitrobenzodiazepines were stable in blood stored for up to 24 months at -20 degrees C, or 4 degrees C over 10 months. Their respective 7-amino metabolites were, however, relatively unstable at -20 degrees C with a significant loss (29%) after 2 months. At 4 degrees C a 21% loss occurred after 1 month. Freeze/thawing was found not to affect the concentration of nitrobenzodiazepine and 7-amino metabolites. These results show that the nitrobenzodiazepines and their metabolites are unstable chemically and metabolically in blood. We advise that blood collected for the purpose of nitrobenzodiazepine determinations should be preserved with sodium fluoride, stored at -20 degrees C and assayed as soon as practicable, preferably within a week of collection.     

Antifungal agents. Part I. Amphotericin B preparations and flucytosine

Traditionally, amphotericin B has been the cornerstone of antifungal treatment. Toxicity, however, is a major dose-limiting factor of amphotericin B deoxycholate. Nevertheless, it continues to have a major role in the treatment of deep-seated mycotic infections. Recently, less nephrotic lipid formulations, including amphotericin B lipid complex, amphotericin B cholesteryl sulfate, and liposomal amphotericin B, have been introduced. The pharmacologic properties, main indications, recommended dosages, related costs, and adverse effects of these various preparations are summarized in this review. Orally administered flucytosine is useful in certain infections, particularly cryptococcal meningitis, but it should be used with caution in patients with renal insufficiency.