Fast Positive Feedback Between the Adrenocortical Stress Response and a Brain Mechanism Involved in Aggressive Behavior.

Aggressive behavior induces an adrenocortical stress response, and sudden stressors often precipitate violent behavior. Experiments in rats revealed a fast, mutual, positive feedback between the adrenocortical stress response and a brain mechanism controlling aggression. Stimulation of the aggressive area in the hypothalamus rapidly activated the adrenocortical response, even in the absence of an opponent and fighting. Hypothalamic aggression, in turn, was rapidly facilitated by a corticosterone injection in rats in which the natural adrenocortical stress response was prevented by adrenalectomy. The rapidity of both effects points to a fast, mutual, positive feedback of the controlling mechanisms within the time frame of a single conflict. Such a mutual facilitation may contribute to the precipitation and escalation of violent behavior under stressful conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Difficult to Let Housing Association Stock in England: Property,Management and Context

Problems related to unpopular housing are not new in Britain's social rented sector. In the past, however, these have generally been associated with housing provided directly by the state through local authorities. For many, the term 'difficult to let' has become synonymous with large, ageing, poor quality estates managed under a centralised framework and subject to a long period of low investment and indifferent management. There has also been a long-standing assumption that social housing allocations systems tend to channel the most vulnerable tenants into the least desirable housing. In fact, the problem of difficult to let property is now as pervasive in the not-for-profit sector managed by housing associations as it is within council housing. In many cases the developments affected are small in scale and, in a significant proportion of cases, recently constructed. In explaining why property becomes difficult to let, the local and regional context is clearly important. The balance between social, economic and housing demand circumstances and property and estate characteristics varies between regions. There is relatively little evidence that difficult to let housing association properties are occupied by disproportionate numbers of the most severely disadvantaged tenants and this suggests that something has happened to modify the segregating effects of allocations systems observed in earlier studies. Nevertheless, this apparent change must be seen within the context of the general trend towards a residual role for social housing in its entirety. The social class and income range of new social sector tenants now is much diminished by comparison with earlier decades with few distinctions between the occupiers of difficult to let and other housing.     

ZXJ10机IN业务功能扩展及实现

本文从智能网的基本概念入手,论述了利用 ZXJ10程控交换系统为发展智能网业务提供支持功能的技术策略以及分阶段实现的过程,并对各个阶段能够实现的业务作了简要介绍。     

Biological trace element research: a multidisciplinary science

The last decade may be regarded as a crucial turning point in new developments in many areas of biological trace element research. It is slowly being recognized as a multidisciplinary science which requires a combination of biological insight and analytical awareness in planning the studies. It is also acknowledged that the complexities involved in dealing with the requirements of trace element research studies in the life sciences demand comprehensive planning of the investigations and use of a variety of techniques, thus bringing together a variety of talents. It cannot be emphasized enough that accurate analytical measurements on biologically and analytically "valid" samples hold the key for success in future biological trace element research studies. These aspects are illustrated.     

Measurement of Adhesive Bond Properties Including Damage by Dynamic Mechanical Thermal Analysis of a Beam Specimen

A method to obtain mechanical properties using a bonded (double) cantilever beam (or three point bend) specimen loaded in a manner to produce pure shear in the adhesive layer is reviewed. A revised mathematical solution which allows for easier interpretation of optimum beam dimensions to the one originally developed by Moussiaux, Cardon and Brinson for the static case is presented. An extension of this solution for a fixed/fixed viscoelastic beam under steady state oscillations developed by Li, Dickie and Morman is also discussed. Previous results using a vibrating beam to determine the complex viscoelastic properties of a bonded beam are reviewed. These results demonstrate conclusively that dynamic mechanical thermal analysis (DMTA) measurements discriminate differences in surface treatments and various environmental conditions. New measurements are presented that indicate the DMTA procedure can be used to quantify damage simulated by imbedded flaws in beams. The procedure is also shown to assess the effects of both humidity and corrosive environments on lap specimens. It is suggested that this technique may ultimately provide a method to quantify the amount of hidden damage in an adhesive joint subjected to fatigue, moisture or corrosive environments.     

氧化作用控制“四硫富瓦烯-葸”二元体系的荧光开关行为

利用Wittig反应将高荧光量子产率的蒽基团通过双键连接在四硫富瓦烯单元上，合成了二元共轭体系化合物TTFan．在氧化作用的控制下，四硫富瓦烯单元的给电子能力降低，TTFan的荧光发射强度增大至原来的十几倍，实现了荧光的“off-on”过程．     

Synergic influence of a surfactant and ultrasonication on the preparation of soluble,conducting polydiphenylamine/silica‐nanoparticle composites

Conducting polydiphenylamine was used to encapsulate silica nanoparticles through the oxidative polymerization of diphenylamine in the presence of ultrasonic irradiation. The polymerization was performed in the presence of sodium lauryl sulfate as a surfactant. Experiments performed in the absence of ultrasound clearly demonstrated that the application of ultrasonication played multiple roles in the preparation of a composite of polydiphenylamine with silica nanoparticles. Ultrasonication dispersed the silica nanoparticles, converted sodium lauryl sulfate to lauryl alcohol, and augmented the dispersion of the silica‐nanoparticle/polydiphenylamine composite in an organic medium. Silica‐nanoparticle/polydiphenylamine composites were also prepared in the absence of ultrasound and/or sodium lauryl sulfate. The silica‐nanoparticle/polydiphenylamine composites were characterized with Fourier trans form infrared spectroscopy, ultraviolet–visible/near‐infrared spectroscopy, and thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3912–3918, 2006     

Role of adhesive–substrate compatibility in adhesion

For substrates such as polyesters having limited capacity for hydrogen bonding or other specific interactions, thermodynamic compatibility of the substrate and adhesive is shown to be a key factor in promoting bondability to the substrate. Such compatibility occurs, as shown by Abere, when the cohesive energy densities (CED) or solubility parameters (δ = √CED) of substrate and adhesive are matched. Investigations with polyester film-adhesive-film model systems with the use of a variety of nonpolar (hydrocarbon) and polar (chlorinated compounds, ethers, esters) adhesives illustrate how compatibility promotes bondability to poly(ethylene terephthalate). The poor adhesion of polyester fibers to resorcinol–formaldehyde–latex (RFL) adhesives is attributed to the incompatibility of resorcinol (δ = 16.0) with the polyester (δ = 10.3). Adhesion to RFL was improved by substituting the more compatible n-hexyl resorcinol (δ = 12.5) for resorcinol in RFL adhesives. Currently, the best adhesive systems for polyester tire yarns are those (e.g., isocyanate–epoxy) involving formation of urethane polymers having matching δ values with poly(ethylene terephthalate).     

Melting points of synthetic wax esters

Saturated, monoenoic and dienoic wax esters, C₂₆−C₄₀, have been synthesized from even-numbered fatty alcohols and acids. In homologous series of saturated esters, the increments of melting points follow a regular trend except for those esters which have an acid moiety two carbon atoms shorter than the alcohol moiety. These wax esters have melting points higher than interpolation would predict. Monoenoic wax esters with the double bond in the alcohol chain have melting points about 10 C higher than their isomers with the double bond in the acid chain.