Effect of heat treatment and precipitation state on toughness of heavy section Mn-Mo-Ni-steel for nuclear power plants components

With regard to the mechanical properties of heavy forgings, made from steel grade 508 ASTM Class 3 (20 MnMoNi 5 5) the influence of the cooling intensity during hardening was investigated and the possibilities and limits of accelerating the cooling rate were studied. The importance of the transformation heat is discussed. It can be concluded from this, that it is impossible to avoid the formation of upper bainite as a typical microstructure of heavy forgings from this steel type.To obtain high impact energy the annealing condition must be conform with this type of microstructure. The reason for impact decrease by over-annealing is related to Mo₂C precipitation in the bainitic ferrite.Finally, experiences with intercritical heat treatment of this steel type are described and the special behaviour of the microstructure obtained is demonstrated.     

GLC determination of doxepin plasma levels

A procedure is described for extracting doxepin, a tricyclic antidepressant, from plasma and subsequently measuring its concentration by GLC. The developed technique permits the resolution and quantitative determination of the cis- and trans-isomers of doxepin as well as its desmethyl metabolite. The method allows precise, reliable measurement of the drug and one of its metabolities in concentrations as low as 10 ng/ml of plasma.     

正构烷烃的氧化以制取合成脂肪酸的研究

试验了国产的各种硬蜡及软蜡,确定了它们的氧化可能性。提出了可供工业上应用的加速氧化反应的二个方法:改善加入催化剂的方法及在泡沫状态下进行氧化。 对於简化分离氧化蜡亦提出了新方案。 文中还叙述了在氧化初期催化剂的作用,对工艺过程的控制有一定的帮助。     

Regional blood redistribution following blood loss in unanesthetized rats

The authors describe relative changes in the blood filling of 46 vascular areas of the body in rats after a moderate and severe blood loss. Moderate blood loss caused redistribution of the blood from the skin of the chest and from the skin of the posterior limbs, the majority of the abdominal and pelvis minor organs, muscular and bone tissues of the abdomen, pelvis minor and extremities into the brain, heart, lungs, kidneys, stomach and into the muscles of the head and neck. In severe blood loss the changes were analogous, but the blood content in the kidneys and the stomach decreased, and there was also a relative elevation of the blood in the muscles and bones of the chest. The intensity of the redistributive reaction in severe blood loss was less than in moderate blood loss.     

Laser bonded microjoints between titanium and polyimide for applications in medical implants

Bioencapsulation of medical implant devices, and neural implant devices in particular, requires development of reliable hermetic joints between packaging materials that are often dissimilar. Titanium-polyimide is one of the biocompatible material systems, which are of interest to our research groups at Wayne State University and Fraunhofer USA. We have found processing conditions for successful joining of titanium with polyimide using near-infrared diode lasers or fiber lasers along transmission bonding lines with widths ranging from 200 to 300 m. Laser powers of 2.2 and 3.8 W were used to create these joints. Laser-joined samples were tested in a microtester under tensile loading to determine joint strengths. In addition, finite element analysis (FEA) was conducted to understand the stress distribution within the bond area under tensile loading. The FEA model provides a full-field stress distribution in and around the joint that cause eventual failure. Results from the investigation provide an initial approach to characterize laser-fabricated microjoints between dissimilar materials that can be potentially used in optimization of bio-encapsulation design.     

Tailoring texture of amorphous aluminosilicates by using organic additives

Amorphous aluminosilicates and silicas are prepared according to an acid or an alkaline sol-gel synthesis procedure, starting respectively from tetraethylorthosilicate and Al(NO₃)₃ or aqueous silicate and aluminate solutions. The textural behavior of aluminosilicates (%Al between 10 and 60) and silicas upon the addition of formamide, dimethylformamide and ethylene glycol is derived from N₂-adsorption data. Comparison with acid synthesized silicas shows that for both the acid and alkaline aluminosilicates mainly an enlargement of the pore volume takes place. The relative small variations in pore size observed (except for ethylene glycol in the acid synthesis) can not account for the pore volume increase. Dimethylformamide even tends to decrease the pore size. This indicates that addition of organics effectively prevents the collapse of smaller pores. As a function of the Al-content, this feature is most pronounced for gels characterised by the highest degree of condensation (25% Al in acid medium, around 30% Al in alkaline medium). The organic additives do not have a positive effect on the crackfree drying of aluminosilicates gel bodies, except for ethylene glycol. The influence of organic additives on surface charge is established by cation exchange capacity measurements.     

The functional activity of the portal vein as a reflection of the metabolic changes in experimental chronic kidney failure

Current therapeutic efforts to treat chronic and progressive neurodegenerative disease include, for the first time, attempts to regenerate affected nervous tissue using neurotrophic factors. The rationale for using trophic factors includes the understanding that they support neuronal survival and regrowth processes. The potential benefits of trophic factor therapy will be no more realized in the near future than in the treatment of amyotrophic lateral sclerosis (ALS). ALS is pathologically characterized by the selective degeneration of specific populations of cranial and spinal motoneurons. Evidence for the existence of factors that support motoneurons has come from studies demonstrating that motoneurons receive trophic influences from various tissues, both central and peripheral, within their local environment. Although the identity of these putative tissue-derived factors has remained enigmatic, recent studies have demonstrated that several previously characterized trophic factors exhibit trophic influences on motoneurons. Among these are several members of the neurotrophin family, most notably brain-derived neurotrophic factor. These neurotrophins meet most of the criteria to be considered motoneuron trophic factors: they are locally available to motoneurons in vivo; motoneurons express specific receptors for these factors; and exogenous application of these factors mimicks the effects of the uncharacterized endogenous agents. The clinical use of these factors for the treatment of ALS, therefore, appears to be scientifically justified.