Afferent influences on the development of the brain stem auditory nuclei of the chicken: otocyst ablation

The effects of embryonic deafferentation on the morphological development of the avian cochlear nuclei, n. angularis (NA) and n. magnocellularis (NM), were investigated. The right otocyst was surgically removed from chick embryos at 55 to 60 hours of incubation and the subsequent development of total volume, neuron number, and neuron cross-sectional area were studied with quantitative methods in animals sacrificed at 2-day intervals between embryonic days 9 and 19 and at 28 days posthatching. The development of NA and NM is severely affected by otocyst ablation. Between embryonic days 9 and 19, a large group of NA neurons in the medioventral portion of the nucleus on the operated side moves to an ectopic ventromedial position, while the remainder of this nucleus stays in its normal dorsolateral position. Beginning about day 13 of incubation, the normal increase in the volume of NA and the size of its neurons becomes progressively retarded and 40% of its neurons are lost. The growth of NM is also retarded after day 11 of incubation and the growth of mean neuron size is retarded after day 15. There is a 30% loss of neurons in NM which begins after embryonic day 11. The results indicate the primary cochlear fibers make a critical contribution to the growth and maintenance of their target neurons. The absence of this facilitative influence following otocyst ablation becomes apparent just at the time synapses would normally be formed between the the primary auditory afferents and the brain stem auditory neurons. The abnormal movement of neurons in nucleus angularis to an ectopic position after otocyst ablation suggests that primary auditory afferents may serve to stabilize the position of their target cells within the developing brain.     

Dynorphin agonist therapy of Parkinson's disease

Striatal dynorphin system function may be altered in Parkinson's disease. To evaluate whether treatment with a selective dynorphin agonist improves motor symptoms, four parkinsonian patients received single daily injections of spiradoline under controlled conditions. Doses ranging from 1 to 4 micrograms/kg had no discernible effect on motor performance when given alone or in combination with levodopa-carbidopa. Three patients developed dose-limiting adverse effects, especially behavioral alterations. These results suggest that dynorphin replacement strategies, using spiradoline-like kappa-1 agonists, may have limited value in the therapy of patients with Parkinson's disease.     

高密度组装X波段有源相控阵T/R模块

介绍了应用一种新的高密度组装技术来降低X波段有源阵列雷达的成本、重量及体积。文中介绍的组件使用了多层AIN基板、倒装单片微波集成电路芯片(MMIC)、共面波导传输线及无需焊接的用于互连的毛钮扣。论述了设计优化、组件结构与组装技术以及测试结果。关键词：     

Range of sizes of peptide products generated during degradation of different proteins by archaeal proteasomes

The 20 S proteasome processively degrades cell proteins to peptides. Information on the sizes and nature of these products is essential for understanding the proteasome's degradative mechanism, the subsequent steps in protein turnover, and major histocompatibility complex class I antigen presentation. Using proteasomes from Thermoplasma acidophilum and four unfolded polypeptides as substrates (insulin-like growth factor, lactalbumin, casein, and alkaline phosphatase, whose lengths range from 71 to 471 residues), we demonstrate that the number of cuts made in a polypeptide and the time needed to degrade it increase with length. The average size of peptides generated from these four polypeptides was 8 +/- 1 residues, but ranged from 6 to 10 residues, depending on the protein, as determined by two new independent methods. However, the individual peptide products ranged in length from approximately 3 to 30 residues, as demonstrated by mass spectrometry and size-exclusion chromatography. The sizes of individual peptides fit a log-normal distribution. No length was predominant, and more than half were shorter than 10 residues. Peptide abundance decreased with increasing length, and less than 10% exceeded 20 residues. These findings indicate that: 1) the proteasome does not generate peptides according to the "molecular ruler" hypothesis, and 2) other peptidases must function after the proteasome to complete the turnover of cell proteins to amino acids.     

Up-regulation of CCR1 and CCR3 and induction of chemotaxis to CC chemokines by IFN-gamma in human neutrophils

Human neutrophils (polymorphonuclear leukocytes; PMN) respond to some CXC chemokines but do not migrate to CC chemokines. Recent work has shown that chemokine receptors can be modulated by inflammatory cytokines. In this study, the effect of IFN-gamma, a prototypic Th1 cytokine, on chemokine receptor expression in PMN was investigated. IFN-gamma caused a rapid (approximately 1 h) and concentration-dependent increase of CCR1 and CCR3 mRNA. The expression of CCR2, CCR5, and CXCR1-4 was not augmented. IFN-gamma-treated PMN, but not control cells, expressed specific binding sites for labeled monocyte-chemotactic protein (MCP)-3 and migrated to macrophage-inflammatory protein (MIP)-1alpha, RANTES, MCP-3, MIP-5/HCC2, and eotaxin. 7B11, a mAb for CCR3, inhibited the chemotactic response of IFN-gamma-treated PMN to eotaxin, and aminoxypentane-RANTES blocked PMN migration to RANTES. These results suggest that the selectivity of certain chemokines for their target cells may be altered by cytokines produced within an inflammatory context. Since PMN may play a role in orienting immunity toward Th1 responses, it is possible to speculate that IFN-gamma not only promotes Th1 differentiation directly, but also reorients the functional significance of Th2 effector cytokines by broadening the spectrum of their action to include PMN.     

Consumers and evaluation of interactive health communication applications. The Science Panel on Interactive Communication and Health

During the early phase following stroke, patients with aphasia and their families are totally involved in the rehabilitation programme, but later, in the chronic phase, after discharge, the family generally has no support and many problems may arise or become more acute and provoke disturbances in this system. The patients with aphasia and their spouses may feel the situation differently according to their own characteristics, including gender. The present study includes 55 spouses of patients with chronic aphasia and 37 controls (spouses of subjects without physical or cognitive impairments) who filled out a questionnaire concerning their respective spouses (European Brain Injury Questionnaire--EBIQ) and some aspects about themselves. It was concluded, from the opinions expressed by the spouses of patients with chronic aphasia that they have problems in several domains not only related to communication or physical impairments. The opinions of husbands and wives of patients with aphasia, but not of the controls, were different, with more references to behaviour changes in women with aphasia. Spouses' responses also show important changes in their own lives. These results stress the importance of adequate attention to the long-term psychosocial problems of patients and relatives.     

The dMARS Architecture: A Specification of the Distributed Multi-Agent Reasoning System

The Procedural Reasoning System (PRS) is the best established agent architecture currently available. It has been deployed in many major industrial applications, ranging from fault diagnosis on the space shuttle to air traffic management and business process control. The theory of PRS-like systems has also been widely studied: within the intelligent agents research community, the belief-desire-intention (BDI) model of practical reasoning that underpins PRS is arguably the dominant force in the theoretical foundations of rational agency. Despite the interest in PRS and BDI agents, no complete attempt has yet been made to precisely specify the behaviour of real PRS systems. This has led to the development of a range of systems that claim to conform to the PRS model, but which differ from it in many important respects. Our aim in this paper is to rectify this omission. We provide an abstract formal model of an idealised dMARS system (the most recent implementation of the PRS architecture), which precisely defines the key data structures present within the architecture and the operations that manipulate these structures. We focus in particular on dMARS plans, since these are the key tool for programming dMARS agents. The specification we present will enable other implementations of PRS to be easily developed, and will serve as a benchmark against which future architectural enhancements can be evaluated.     

Rational verification: game-theoretic verification of multi-agent systems

Applied Intelligence - We provide a survey of the state of the art of rational verification: the problem of checking whether a given temporal logic formula ? is satisfied in some or all...