METHODS FOR BRAZING CERAMIC AND METAL-CERAMIC JOINTS

Owing to improved manufacturing processes technical ceramics on the basis of oxide as well as nonoxide ceramics have gained an increasing technical potential. Among other joining techniques brazing has proved to be the most flexible joining process that can easily be adapted to various ceramic-metal-combinations. In order to induce a wetting reaction there are two different approaches. The more complicated process encircles a pre-metallization process and a subsequent brazing process. The less sophisticated process is the 'active brazing process' where special brazing alloys are employed that are able to wet ceramic base materials. Although both joining processes are very flexible there are restrictions regarding the filler metals to be used, the premetallization process and the actual (active-) brazing process.     

Camcorders

The author explains from an engineering standpoint, how some of the camcorder components work. He discusses the solid-state image sensor, the photodetector, scanning, the shutter frame rate, optics, the recording mechanism, the viewfinder, special effects, and automatic features. Motion detection, discrimination, and compensation are also covered. Recommendations as to which features are most useful are made     

Power engineering industry interaction at Clemson University

The authors present a successful model of industry/university cooperation in establishing a strong power system curriculum in both the graduate and undergraduate level. Numerous long-term and short-term research projects have been developed to satisfy the university mission and to tackle challenging problems facing the power industry. A unique structure for the Clemson University Electric Power Research Association (CUEPRA) has been established to promote electric power system research and to meet the need for a working communication link between the power industry and the academic community. The power industries involvements in the power program at Clemson University and the strategic improvements that have been accomplished in research and education are outlined     

Linkage between inflammation and coagulation: an update on the molecular basis of the crosstalk

Inflammation and coagulation cannot be considered as two separate processes, since there are several connecting points making them part of unique, defensive host response. The endothelium can be considered as the first link between inflammation and coagulation, since damaged endothelium during inflammation represents a surface where proteins involved in both coagulation and the development of inflammation are expressed. During inflammation, cytokines modulate the coagulation system by downregulating the expression of thrombomodulin and the activation of protein C pattern but, at the same time, they induce the expression of tissue factor, modifying, in this way, the balance between procoagulant and anticoagulant activities. At the same time, at the site of tissue injury, platelets become activated and release several mediators that modify tissue integrity. Thrombin, formed following activation of the coagulation cascade, is essential to promote haemostasis but also stimulates several cell functions, including chemotaxis and mitogenesis, which are responsible for the spreading of the lesion and the tissue repair process. Therefore, in the study of inflammation the involvement of the coagulation pathway has to be taken into account, since the interaction between coagulation and inflammation pathways is a critical issue.     

Setting the record straight.

Replies to comments by H. W. Marsh and L. A. Roche (see record 1997-43129-003) on the author's article (Educational Policy Analysis Archives, 1997) on student evaluation and academic freedom. The author expresses his dismay that Marsh and Roche misrepresented (not misinterpreted) the article without documenting their misrepresentation. A documented response to this undocumented misrepresentation is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The distribution of HBV, HCV and HGV among livers with fulminant hepatic failure of different aetiology

BACKGROUND/AIMS: The aim of the study was to assess the impact factor of HCV and HGV in fulminant hepatic failure. METHODS: The 5'-untranslated regions of HCV RNA and HGV RNA and a segment of the core antigen sequence of HBV were amplified after extracting the nucleic acids from snap-frozen tissue aliquots from explanted livers of 26 consecutive patients undergoing orthotopic liver transplantation for fulminant hepatic failure preoperatively diagnosed as either autoimmune (n=2), HAV/HBV (n=8), toxic (n=4) or aetiologically unknown (n=12). RESULTS: HCV RNA was detected in five of 26 (19.2%) livers with fulminant hepatic failure. All five HCV RNA-positive livers belonged to the group of non-toxic, non-autoimmune liver failure (n=20), three of them were found in the group of liver failure with unknown aetiology (n=12) and two in the group of HBV-associated liver failure (n=7), making an HCV incidence of 25%, 25% and 28.6%, in the different groups, respectively. HGV RNA was detected in 10 of 17 (58.8%) explants and in all four groups of fulminant hepatic failure as defined preoperatively. HBV DNA was identified in six livers of 26 patients (23.1%) with fulminant hepatic failure. Neither HCV RNA nor HBV DNA was detected in the livers of patients with toxic or autoimmune fulminant hepatic failure. CONCLUSIONS: These results indicate that HBV and HCV, but not HGV, play an aetiologic role in fulminant hepatic failure. HCV-positive cases were concentrated either in the group of otherwise unexplained fulminant hepatic failure or in the group of HBV fulminant hepatic failure. HGV-positive cases, on the other hand, were found within all four preoperatively defined groups, indicating a role as cofactor rather than as single aetiologic agent.     

Membrane-bound calmodulin in Xenopus laevis oocytes as a novel binding site for melatonin

Melatonin has been suggested as a physiological antagonist of calmodulin. In this work, we have characterized melatonin binding sites in Xenopus laevis oocyte membranes. Binding of [125I]melatonin by X. laevis oocyte membranes fulfills all criteria for binding to a receptor site. Binding was dependent on time, temperature, and membrane concentration and was stable, reversible, saturable, and specific. The binding site was also pharmacologically characterized. Stoichiometric studies showed a high-affinity binding site with a Kd of 1.18 nM. These data are in close agreement with data obtained from kinetic studies (Kd=0.12 nM). In competition studies, we observed a low-affinity binding site (Kd=63.41 microM). Moreover, the binding site was characterized as calmodulin. Thus, binding was dependent on calcium and blocked by anti-CaM antibodies in a concentration-dependent manner. Calmodulin inhibitor chlorpromazine also inhibited binding of the tracer. From these results, it is suggested that membrane-bound calmodulin acts as a melatonin binding site in Xenopus laevis oocytes, where it might couple cellular activities to rhythmic circulating levels of melatonin. This hypothesis correlates with the previous findings describing melatonin as a physiological antagonist of calmodulin.