Simple Approximations for Token Rings

Recently, a conservation law for the waiting times at a token ring has been derived. This conservation law is used here to develop simple approximations to the waiting times at individual queues on a token ring. Although exact algorithms are available, they may require significant computation time. In contrast, the approximation developed here is easily calculated on a pocket calculator, and is more accurate than earlier approximations.     

Traffic engineering of the radio interface for cellular mobilenetworks

The paper reviews traffic-related issues in the operation of the radio interface in cellular mobile networks operating with FDMA, TDMA, or CDMA technology. The emphasis is on issues which affect the traffic performance of the network, rather than on transmission technology, or transmission quality measures such as bit error rate. The author reviews the important traffic performance measures for cellular systems and the issues of channel assignment, handoff, access control, traffic modeling, and traffic management. Traffic modeling for all types of networks is considered in some depth, both by drawing analogies with fixed-wire networks, and by considering cellular-specific modeling. From the modeling results, he concludes that reuse-based networks such as FDMA and TDMA possess quite different traffic characteristics from CDMA networks     

Evidence for nodular epileptogenicity and gender differences in periventricular nodular heterotopia

The new synthetic oleanane triterpenoid 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) is a potent, multifunctional molecule. It induces monocytic differentiation of human myeloid leukemia cells and adipogenic differentiation of mouse 3T3-L1 fibroblasts and enhances the neuronal differentiation of rat PC12 pheochromocytoma cells caused by nerve growth factor. CDDO inhibits proliferation of many human tumor cell lines, including those derived from estrogen receptor-positive and -negative breast carcinomas, myeloid leukemias, and several carcinomas bearing a Smad4 mutation. Furthermore, it suppresses the abilities of various inflammatory cytokines, such as IFN-gamma, interleukin-1, and tumor necrosis factor-alpha, to induce de novo formation of the enzymes inducible nitric oxide synthase (iNos) and inducible cyclooxygenase (COX-2) in mouse peritoneal macrophages, rat brain microglia, and human colon fibroblasts. CDDO will also protect rat brain hippocampal neurons from cell death induced by beta-amyloid. The above activities have been found at concentrations ranging from 10(-6) to 10(-9) M in cell culture, and these results suggest that CDDO needs further study in vivo, for either chemoprevention or chemotherapy of malignancy as well as for neuroprotection.     

The pharmacokinetics, antigenicity, and fusion-inhibition activity of RSHZ19, a humanized monoclonal antibody to respiratory syncytial virus, in healthy volunteers

Single ascending doses of RSHZ19 (also known as SB 209763), a humanized monoclonal antibody (MAb) directed to the fusion protein of respiratory syncytial virus, were administered to healthy men to evaluate the safety, pharmacokinetics, antigenicity, and fusion inhibition (FI) activity of RSHZ19. Doses of RSHZ19 (0.025-10.0 mg/kg) or placebo were infused over 30 min, and subjects were followed for 10 weeks. Plasma concentrations of RSHZ19 and RSHZ19-specific antibodies were determined by ELISAs. FI titers were used to evaluate the ability of plasma to inhibit virus-induced fusion of VERO cells previously infected with RS Long strain virus. Twenty-six subjects, mean age 24, completed the study. RSHZ19 was safe and well tolerated, and no subject developed antibodies to RSHZ19 during follow-up. RSHZ19 had low plasma clearance and a half-life of approximately 23 days, similar to native IgG. Increases in FI titers relative to pretreatment levels were seen 24 h after MAb administration in all 4 subjects given 10 mg/kg and in 2 of 4 given 5 mg/kg.     

Role of monoamines in the control of hormones of sexual receptivity in the female rat.

Investigated the involvement of indole- and catecholamines in the hormonal regulation of sexual receptivity in ovariectomized Sprague-Dawley rats. Drugs that reduce 5-hydroxytryptamine, dopamine, and adrenaline or increase noradrenaline neurotransmission tended to facilitate the occurrence of estrous behavior in estrogen-treated Ss, and drugs having opposite effects tended to inhibit receptivity induced by estrogen and progesterone. Estrogen decreased noradrenaline turnover in cortex and brain stem; progesterone enhanced this effect in brain stem but prevented it in cortex. Both hormones tended to block noradrenaline uptake in hypothalamus in vitro. In a schedule used to induce receptivity, estrogen accelerated serotonin turnover, an effect prevented by progesterone. Results suggest that a number of monoamines may be involved in the control by hormones of estrous behavior and that hormones affect both amine turnover and uptake mechanisms. (85 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A note on the pseudoconservation laws for cyclic service systemswith limited service disciplines

A cyclic service system with the limited service discipline, where up to a fixed number k of messages can be served at each visit to each queueing station is presented. This limit may be utilized in exhaustive or gated mode. A pseudoconservation law is derived for the exhaustive form of limited service, and a derivation is provided for the gated form of limited service     

Effects of immobilization restraint on Syrian golden hamsters

A 2 x 2 x 4 factorial design was used to study variation of protein and fat contents in beef broths as affected by cut type (flank, shank), salt treatments (addition of salt to the medium, no salt), and initial temperatures of simmering (25, 70, 75, and 100 degrees C). Flank portions yielded slightly more protein (0.29 g/100 mL) and had three-fold less fat (0.39 g/mL) than those of shank (0.25 and 1.12 g/mL, respectively) (P < 0.05). No linear relationship of temperature and amount of extractable components was observed, but it was clear that the greatest protein extraction was accomplished when meat was immersed in cooking water at boiling point (P < 0.05). In general, salting of water reduced fat content of beef broths. However, a significant Salting x Cut type interaction showed this effect was only present in shanks (P < 0.05). Conversely, the reducing effect (P < 0.05) of salting on amount of protein extracted from flank was not observed in shanks. Based on these data, we conclude that larger amounts of protein and less fat could be transferred from meat pieces to the medium by immersing beef in salted water at the boiling point.     

Steam jet ejector system for vehicle air conditioning

This paper describes the design of a steam jet ejector. The ejector forms the major component in an ejector cycle, which could be installed in vehicles to provide air-conditioning. The cycle could be driven by waste heat provided by the exhaust from the engine and/or cooling water supply.

The design of the ejector was derived from 1-D analysis, as well as from guidelines published in the ESDU series. The ejector was then manufactured and tested in a laboratory controlled test rig that simulated conditions present in a small motor vehicle.

The ejector analysis was then compared with the practical test data under design conditions as well as off design conditions. Comparisons were made using the mass flow ratio of the ejector. The coefficient of performance (COP_R) of the system is also presented for all operating conditions tested.