Histamine H3 receptors contribute to drinking elicited by eating in rats

A role for endogenous histamine and its H3 receptor subtype for mediating drinking elicited by eating was examined in adult male Sprague-Dawley rats. The i.p. injection of the H3 agonist R-alpha-methylhistamine (Ramh, 2.5 mg/kg) shortened the latency to initiate drinking and increased 1-h water intake in nondeprived rats freely eating pellets and drinking water. The ICV injection (through a surgically implanted chronic cannula) of 10 micrograms Ramh increased water intake; this Ramh-induced drinking was abolished by previous ICV injection of the H3 antagonist thioperamide (Th, 60 micrograms). For rats drinking and eating after 24-h food deprivation, s.c. Th inhibited drinking behavior: for example, 10 mg/kg Th s.c. delayed the latency to initiate drinking and inhibited 1-h water intake without inhibition of food intake. In contrast, 60 micrograms Th ICV failed to inhibit food-related drinking in rats eating after food deprivation. For nondeprived rats eating a small cracker, 10 mg/kg Th s.c. delayed the latency to initiate drinking and abolished water intake without effect of eating, and 60 micrograms Th ICV had similar effects upon drinking elicited by ingestion of cracker. The IG infusion (through a surgically implanted gastric catheter) of 2 ml 600 or 900 mOsm/kg NaCl, a treatment that is subthreshold for increase in systemic plasma osmolality at the initiation of drinking, elicited drinking that was abolished by 10 mg/kg Th s.c. and attenuated by 60 micrograms Th ICV. The IG infusion of 2 ml 1800 mOsm/kg NaCl, a treatment that is above threshold for increase in systemic plasma osmolality, elicited drinking that was attenuated by 10 mg/kg s.c. or 60 micrograms Th ICV. These results demonstrate that peripheral and central H3 receptors for histamine have a role in drinking elicited by eating and the postprandial gastrointestinal osmotic consequences of eating. These findings extend the evidence demonstrating a histaminergic contribution to food-related drinking in rats.     

Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory

We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25–3.5 GeV. The prototype consisted of an array of 6 × 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm × 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/π separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.     

Mixing in processing of thermoplastics by extrusion

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993.     

Reduction of loading effect by tungsten etchback in a magneticallyenhanced reactive ion etcher

The plug loading effect occurring during the etchback of tungsten was investigated in a magnetically enhanced reactive ion etcher using SF ₆/Ar mixtures. It was found that while the plug loading effect is independent of varying SF₆/Ar flow rate ratio and magnetic field intensity, it is reduced under the condition of high selectivity of tungsten relative to TiN which was achieved at high chamber pressure and low RF power. It is proposed that when TiN is used as a glue layer, the W etch rate enhancement in the plug is mainly controlled by a local loading effect. Under the optimized etchback conditions the plug loss was successfully controlled without the tungsten residue left on severe topology     

Postembryonic neurogenesis in the central nervous system of the tobacco hornworm, Manduca sexta. III. Spatial and temporal patterns of proliferation

Postembryonic neurogenesis leads to a dramatic increase in the number of functional neurons within the segmental ganglia of the moth, Manduca sexta. These adult-specific neurons are generated during larval life by segment-specific arrays of individually identifiable stem cells, or neuroblasts (Nbs). By the end of the feeding larval stage, each Nb has generated a discrete nest of progeny, which ranges in size from less than 10 to more than 70 progeny. The sizes of these identifiable nests of progeny vary in a segment-specific manner, with the thoracic nests containing a greater number of progeny compared with their homologues in the simpler abdominal ganglia. In order to describe those factors that influence the size of the post-embryonic neuronal lineages, we examined the spatial and temporal pattern of postembryonic neurogenesis in the segmental ganglia of Manduca. The rates at which the identifiable nests accumulated progeny were estimated by counting the number of progeny within the nests, using sectioned material isolated from animals at stages ranging from embryonic hatching until the end of the feeding larval stage. All of the postembryonic Nbs began to generate progeny at around the time of the molt to the third larval instar. Each nest added progeny at a rate that was a characteristic of its identity and segment of origin. Although all of the nests within the thorax continued to accumulate progeny throughout the feeding larval stage, several of the abdominal nests showed little or no growth following the molt to the fifth larval instar. The thymidine analog 5-bromo 2-deoxyuridine (5-BrdU) was used to estimate the mitotic rates of the identifiable Nbs. The number of labeled progeny within a nest 24 h after application of 5-BrdU ranged from a low of 1 to 2 to a high of 11 to 13 labeled cells. In some instances there was a good correlation between the estimated mitotic rate of an identified Nb and the rate of growth of its associated nest of progeny. However, several of the identifiable nests accumulated progeny at a slower rate than predicted based on the estimated mitotic rate of the Nb. Cell death appears to be responsible for slowing the growth of the nests during the feeding larval stage. We estimate that 10% to 70% of the neurons generated during the feeding larval stage degenerate within 24 h of their birth. The level of cell death observed within a nest was dependent on both its identity and its segment of origin.     

Performance evaluation of the Golay code pulse compression technique

The Center for NDE, Iowa State University, has developed a laboratory prototype Golay code pulse compression system and tested it on a variety of materials. The performance of the system was evaluated in terms of signal-to-noise ratio enhancement (SNRE), resolution, and computation speed. The system's error sources also were discussed. The Golay code pulse compression was simulated on a computer and demonstrated the effective noise suppression. In addition, an equivalent pulse of the Golay code (delta-like pulse) was derived theoretically using a simple ultrasonic inspection model, which demonstrated its equivalence on the output correlated signal. Overall, the pulse compression technique extended the detection range for a given peak power and considerably reduced the system'swhite noise, hence providing enhanced signal-to-noise ratios (SNRs). An average of 30 dB improvement in SNR was obtained from highly energy-absorbent materials such as rubber, plastics, corks (insulation materials), and thick composites using the Golay codes of up to 512 bits. However, the technique did not effectively reduce coherent scattering noises from the coarse grain boundaries in cast stainless steels, Inconel weld metal, and material lay-ups in thin composites. Furthermore, it was found that, depending upon the system's hardware capabilities, the overall performance could be degraded considerably.     

d-Tubocurarine accentuates the burn-induced upregulation of nicotinic acetylcholine receptors at the muscle membrane

BACKGROUND: Increases in acetylcholine receptors (AChRs) at the muscle membrane, induced by burn injury, have been associated with a hyperkalemic response to succinylcholine and resistance to d-tubocurarine-like drugs. Muscle relaxants often are administered to burn-injured patients in the intensive care unit to facilitate mechanical ventilation. This study in rats tested whether continuous administration of d-tubocurarine in subparalytic doses exaggerates the upregulation of AChRs induced by burn trauma. Subparalytic doses were used to avoid the confounding effects of immobilization. METHODS: Three days after an approximate 50% body surface area burn or sham injury, the animals received an infusion of 3.03 +/- 0.05 micrograms/h of d-tubocurarine or equal volume of saline directly to the left gastrocnemius muscle via catheter connected to a subcutaneously implanted osmotic pump. After 7 days of d-tubocurarine or saline infusion, the AChRs were quantitated using 125I-alpha-bungarotoxin. The AChRs on the d-tubocurarine or saline-infused left gastrocnemius were compared to the contralateral gastrocnemius in the same group. The right or left gastrocnemius AChRs were compared to the ipsilateral muscles between groups. These intra- and intergroup comparisons allowed the delineation of the effects of catheter irritation, burns, or d-tubocurarine on AChRs. RESULTS: Daily examination of the withdrawal response to toe-pinch revealed no evidence of paralysis. Weight loss in the burn-injury animals receiving d-tubocurarine or saline was similar, confirming that the infusion of d-tubocurarine did not impair the mobility of the animals to move and feed. The plasma d-tubocurarine concentration after 7 days of infusion was 26.0 +/- 12 ng/ml (mean +/- SE). Regardless of burn or sham injury or of d-tubocurarine or saline infusion, the concentration of AChRs on the left was consistently greater than in the contralateral right gastrocnemius muscles within the same group, indicating that manipulation of the area alone can result in upregulation of AChRs. The AChRs in the right gastrocnemius of burn-injured animals were greater than those in the same muscle of sham-injured animals, regardless of saline (7.24 +/- 0.9 vs. 5.7 +/- 0.5 fmoles/mg protein, P = 0.06) or d-tubocurarine (7.3 +/- 0.4 vs. 5.7 +/- 0.5, P < 0.05) infusion to the burn-injury groups. AChRs in the left gastrocnemius of burn-injury animals receiving d-tubocurarine were significantly greater than those in burn- or sham-injury animals receiving saline (13.9 +/- 1.1 vs. 9.8 +/- 1.2 and 7.1 +/- 0.5 fmoles/mg protein, respectively, P < 0.05). CONCLUSIONS: Burn-induced upregulation of AChRs is accentuated by infusion of subparalytic doses of d-tubocurarine. Concomitant administration of d-tubocurarine to burn-injured patients may result in further exaggeration of the aberrant responses to neuromuscular relaxants.     

Phase-insensitive all-optical transistors based on second-ordernonlinearities

We demonstrate and compare two phase-insensitive all-optical transistors (AOT's) based on frequency-degenerate quadratic three-wave interactions. In particular, we demonstrate gain using KTP in a type II geometry. Both AOT's exploit the phase insensitivity inherent to three-wave parametric processes when only two fields are input, providing amplification of a small signal at the operating frequency via the interaction with a second-harmonic wave. The first scheme is based on successive up- and down-conversion (i.e., cascading) while the second relies on parametric down-conversion. We obtain gains of 5 and 160 in the two configurations, respectively, with a significant background and output coherent to the pump in the first case, no background and coherence between output and signal in the second     

Mode analysis of DFB SE lasers

This paper presents theoretical results on mode characteristics of surface-emitting (SE) lasers utilizing an active second-order grating section. Based on a coupled-mode approach, longitudinal modes and the associated space-harmonic transverse modes are calculated via a numerical technique. From these, the lasing-mode spectrum, near- and far-field patterns of the radiation mode, and the surface-emission power efficiency are obtained. Effects of the substrate reflector and the grating parameters are also investigated. Finally, comparisons are made with conventional, edge-emitting DFB lasers. The results indicate that with a suitable choice of structural parameter values, DFB SE lasers can be made to possess both the spectral discrimination of the conventional DFB lasers and the advantages of SE lasers at the same time and also that the second lowest longitudinal mode may be preferred over the fundamental longitudinal mode for many applications due to its symmetric field distribution