Neurofilament-L homopolymers are less mechanically stable than native neurofilaments

Neurofilaments are cytoskeletal components of neurones that are thought to play an important structural role in the axon. Specific functions of neurofilaments are not yet well defined; however, other intermediate filaments are known to have structural and mechanical functions in different cell types. The atomic force microscope (AFM) can be used to visualize and manipulate biological structures through direct physical contact. This allows the AFM to be used to probe the mechanical properties of these structures. In this paper we present AFM images of native neurofilaments isolated from bovine spinal cord, composed of NF-L, NF-M and NF-H, and filaments polymerized in vitro from purified NF-L. Morphologically these structures, in solution and under ambient conditions, are in agreement with previous data from electron microscopy. However, repeated scanning of NF-L homopolymers (in solution) produced significant disruptions of segments of filaments, both within and at the ends of the filaments. This disruption resulted in complete loss of portions of the filaments and in breaks in the continuity of the filaments. Repeated scanning of isolated native neurofilaments under similar conditions produced no detectable structural changes. Under extremely high applied forces the native neurofilaments were bent and distorted by the action of the AFM tip, but were never broken. These data suggest that purified NF-L is not sufficient to confer complete mechanical stability to neurofilaments.     

Reduced microvascular thrombosis and improved outcome in acute murine stroke by inhibiting GP IIb/IIIa receptor-mediated platelet aggregation

Treatment options in acute stroke are limited by a dearth of safe and effective regimens for recanalization of an occluded cerebrovascular tributary, as well as by the fact that patients present only after the occlusive event is established. We hypothesized that even if the site of major arterial occlusion is recanalized after stroke, microvascular thrombosis continues to occur at distal sites, reducing postischemic flow and contributing to ongoing neuronal death. To test this hypothesis, and to show that microvascular thrombosis occurs as an ongoing, dynamic process after the onset of stroke, we tested the effects of a potent antiplatelet agent given both before and after the onset of middle cerebral arterial (MCA) occlusion in a murine model of stroke. After 45 min of MCA occlusion and 23 h of reperfusion, fibrin accumulates in the ipsilateral cerebral hemisphere, based upon immunoblotting, and localizes to microvascular lumena, based upon immunostaining. In concordance with these data, there is a nearly threefold increase in the ipsilateral accumulation of 111In-labeled platelets in mice subjected to stroke compared with mice not subjected to stroke. When a novel inhibitor of the glycoprotein IIb/IIIa receptor (SDZ GPI 562) was administered immediately before MCA occlusion, platelet accumulation was reduced 48%, and fibrin accumulation was reduced by 47% by immunoblot densitometry. GPI 562 exhibited a dose-dependent reduction of cerebral infarct volumes measured by triphenyltetrazolium chloride staining, as well as improvement in postischemic cerebral blood flow, measured by laser doppler. GPI 562 caused a dose-dependent increase in tail vein bleeding time, but intracerebral hemorrhage (ICH) was not significantly increased at therapeutic doses; however, there was an increase in ICH at the highest doses tested. When given immediately after withdrawal of the MCA occluding suture, GPI 562 was shown to reduce cerebral infarct volumes by 70%. These data support the hypothesis that in ischemic regions of brain, microvascular thrombi continue to accumulate even after recanalization of the MCA, contributing to postischemic hypoperfusion and ongoing neuronal damage.     

Effects of thermo-mechanical processing and trace amount of carbon addition on tensile properties of Cu–2.5Fe–0.1P alloys

The effects of thermo-mechanical processing, including intermediate aging treatment and/or solution heat treatment, and a trace amount of carbon (C) addition were studied on tensile behavior of Cu–2.5Fe–0.1P alloys. In this study, Cu–2.5Fe–0.1P alloy sheets without and with a carbon content of 0.05 wt.% were cast and subsequently rolled and thermo-mechanically treated following various processing routes. The introduction of intermediate aging treatment between cold rolling improved the tensile strength of Cu–2.5Fe–0.1P alloys. Solution heat treatment prior to aging was proved to be detrimental on the tensile strength, probably due to recovery and recrystallization causing the complete loss of work hardening during previous cold rolling. The present study also suggested that two-step aging is more effective in improving the strength of Cu–2.5Fe–0.1P alloys than one-step aging. The effect of C addition on improving the tensile strength of Cu–2.5Fe–0.1P alloys was real but marginal, probably due to the limited solubility of C in Cu–2.5Fe matrix. The effects of intermediate heat treatments between cold-rolling processes on tensile properties of Cu–2.5Fe–0.1P specimens with and without C addition are discussed based on optical, scanning electron microscope (SEM) and transmission electron microscope (TEM) micrographs, and SEM fractographs.     

Factors affecting image acquisition during scanning laser polarimetry

Prognosis of systemic sclerosis (scleroderma, Ssc) is largely depending on involvement of internal organs. Abnormalities of the gastrointestinal tract are found most frequently (85%), especially decreased motility of the oesophagus, which has little impact on the longterm clinical course of Ssc. Pulmonary manifestations can be demonstrated in 40-90% of patients; one must distinguish between pulmonary hypertension or fibrotic lung disease. The heart is affected in 50% of cases. Patchy or diffuse myocardial fibrosis, as well as pericarditis and pericardial effusions can induce symptoms of arrhythmia or congestive heart failure. Renal involvement is associated with increased mortality and occurs in 45% of Ssc, producing proteinuria, hypertension, scleroderma renal crisis and renal failure. In conclusion, involvement of the lungs, heart and kidneys are determining factors for the longterm course of systemic sclerosis.     

Enhancing Security and Privacy in Traffic-Monitoring Systems

Intelligent transportation systems increasingly depend on probe vehicles to monitor traffic: they can automatically report position, travel time, traffic incidents, and road surface problems to a telematics service provider. This kind of traffic-monitoring system could provide good coverage and timely information on many more roadways than is possible with a fixed infrastructure such as cameras and loop detectors. This approach also promises significant reductions in infrastructure cost because the system can exploit the sensing, computing, and communications devices already installed in many modern vehicles. This architecture separates data from identities by splitting communication from data analysis. Data suppression techniques can help prevent data mining algorithms from reconstructing private information from anonymous database samples     

生产微合金化钢的几点考虑

在20世纪60～80年代,连续浇铸是钢铁工业的一项重要的工艺变革。这项技术无论对提高炼钢生产效率还是改善产品质量都产生了深刻的影响。然而,为保持产品竞争力和成本效益,需要一个统筹的炼钢方法。从铁水生产开始或者从冶炼开始,经过精炼到连铸,再到轧钢和后续工序,钢产品的整条生产路线应该整体可控。关于连铸,有2个实例可以说明这种发展趋势:改进中间包设计和冶金技术,优化浸入式水口和高水平的结晶器液面控制。无止境的洁净钢研究已经从连铸机本身转到钢包冶金。同样,无缺陷表面质量研究不再简单地专注于连铸技术,同时也将炼钢考虑进去。随着结构钢品种的合金设计转变,从普通的中碳锰钢到裂纹敏感的现代低碳微合金化HSLA钢,连铸机的设计和技术发展并驾齐驱。     

The separation of manganese from cobalt by D2EHPA

The separation of manganese from cobalt in sulphate solution by D2EHPA diluted with kerosene is reported. Manganese can be separated by controlling the aqueous and organic pH in the neighborhood of 4.2 and 2.0, respectively. A continuous separation process is proposed. Results indicate that a high degree of separation between manganese and cobalt can be achieved.     

Hydrogen peroxide oxidation of tertiary amines

Oxides of tertiary amines, such as dimethyldodecylamine oxide, are known to be useful as detergents and foam stabilizers, and are now in commerical use. The results of an investigation leading to the selection of optimum conditions for producing these compounds are reported. A variety of hydrogen peroxide-derived systems for amine oxidation were investigated. These included hydrogen peroxide in water and in nonaqueous solvents, and peroxy acids under various reaction conditions. Reductometric, acidimetric, and gas chromatographic procedures were used for analysis of reaction mixtures. The preferred reaction uses hydrogen peroxide as oxidant and water as the reaction medium. The product of this reaction is a 30–40% solution of the amine oxide. Other factors affecting the rate and extent of conversion, such as amine purity, are discussed. Presented at the AOCS meeting in Toronto, Ontario, 1962.