Copper deterioration in a water distribution system of a county hospital in Germany caused by microbially influenced corrosion – II. Simulation of the corrosion process in two test rigs installed in this hospital

A copper corrosion process of unknown origin in a county hospital in Germany has been observed in the cold and warm water supplies shortly after operating the hospital. It seemed that the cause of these damages could be attributed to microbially induced corrosion. The evaluation of damages indicated that the constructive design of the installations and the operating conditions are parameters influencing the pitting corrosion to a large extent. In the past other damages have occurred in this water distribution area already [1]. Two test rigs have been installed in the county hospital to simulate the corrosion process and to get a profounder understanding of the corrosion mechanism. The results obtained from these test rigs are compared to the findings in the hospital a few years ago concerning corrosion of copper as well as analytical, biological and operational parameters.     

Intergroup relations and South African social psychology: Historical ties.

Seven research themes in South African social psychology are identified and sketched historically: the use of psychological tests to make comparisons between groups; attitudes; authoritarianism; the "marginal personality"; the contact hypothesis; a state-sponsored investigation into intergroup relations; and social identity theory. It is argued that the development of these themes has to be examined in conjunction with changes in the political discourse in South Africa about "race." (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isolation and characterization of proteolipids from rat liver (LSP) and kidney (KSP)

In this study, the biochemical characteristics of proteolipids of rat liver and kidney homogenates were compared. In all preparations, the proteo-lipids were eluted at the void volume of the Biogel A-15 m column after gel chromatography, and a molecular weight over 15×10⁶ was estimated. Electron microscopy of the concentrated void volume fractions showed globular particles with diameters of 30–100 nm for liver (LSP) and 30–60 nm for kidney (KSP) preparations that might be formed from plasma membrane fragments. After ultracentrifugation in a CsCl gradient, rat LSP and KSP floated in a small density range from 1.16–1.17 g/ml. There was no significant difference between the relative percentages of phospholipids, triglycerides and cholesterol of both proteo-lipids. However, the relative mean amount of total protein in rat KSP (60.4% vs 50.4%) was significantly higher and the content of free fatty acids (4.3% vs 12.6%) significantly lower compared to rat LSP. SDS-PAGE revealed at least 12 protein subunits ranging from 15,000–130,000 in both preparations, but one protein of about M_r 49,000 might represent a liver specific component. The isolated proteo-lipids from rat liver and kidney homogenates showed similar biochemical characteristics as those from human sources, which could explain the known cross-reactivity of antibodies against these preparations. The putative function of these proteo-lipids is not known, although there is some evidence from human studies that they carry receptor proteins.     

PET and CBF studies of chronic hydrocephalus: a contribution to surgical indication and prognosis

The management of acute myoglobinuric renal failure, the major complication of rhabdomyolysis, continues to be a treatment dilemma for the clinician as limited therapeutic options are available. Previously, we have demonstrated that continuous arteriovenous hemofiltration (CAVH) is an effective technique for removing myoglobin in an animal model. In the present study, swine were administered four grams of equine myoglobin intravenously and underwent the continuous veno-venous hemofiltration (CVVH) procedure for six hours each. Animals were studied in each of the following groups: CVVH at a pump rate 100 ml/minute, CVVH at a pump rate 200 ml/minute and CVVH at a pump rate 100 ml/minute plus dialysis at a dialysate flow rate of one Liter/h. Once the filtering process was initiated there was a rapid and sustained production of ultrafiltrate in all groups. The amount of myoglobin excreted in the ultrafiltrate over the six-hour filtering period was 688, 948 and 570 mg which corresponded to 17, 24 and 14 percent of the administered dose, respectively, for the three treatments. In comparison to previous CAVH experiments, CVVH removed more circulating myoglobin and the addition of the dialysis component did not appear to improve removal. Based on these findings, it appears that the CVVH hemofiltration system is a viable option for the removal of systemic myoglobin.     

The active sites of the eukaryotic 20 S proteasome and their involvement in subunit precursor processing

The 26 S proteasome is the central protease involved in ubiquitin-mediated protein degradation and fulfills vital regulatory functions in eukaryotes. The proteolytic core of the complex is the 20 S proteasome, a cylindrical particle with two outer rings each made of 7 different alpha-type subunits and two inner rings made of 7 different beta-type subunits. In the archaebacterial 20 S proteasome ancestor proteolytically active sites reside in the 14 uniform beta-subunits. Their N-terminal threonine residues, released by precursor processing, perform the nucleophilic attack for peptide bond hydrolysis. By directed mutational analysis of 20 S proteasomal beta-type proteins of Saccharomyces cerevisiae, we identified three active site-carrying subunits responsible for different peptidolytic activities as follows: Pre3 for post-glutamyl hydrolyzing, Pup1 for trypsin-like, and Pre2 for chymotrypsin-like activity. Double mutants harboring only trypsin-like or chymotrypsin-like activity were viable. Mutation of two potentially active site threonine residues in the Pre4 subunit excluded its catalytic involvement in any of the three peptidase activities. The generation of different, incompletely processed forms of the Pre4 precursor in active site mutants suggested that maturation of non-active proteasomal beta-type subunits is exerted by active subunits and occurs in the fully assembled particle. This trans-acting proteolytic activity might also account for processing intermediates of the active site mutated Pre2 subunit, which was unable to undergo autocatalytic maturation.     

Entrepreneurs' experience, expertise, and the performance oftechnology-based firms

This study investigates the relationship between the experience of founders and the performance of their firms. Previous research has reported mixed evidence of a relationship between entrepreneurs' experience and their firms' performance. It is argued that this mixed evidence is due to the mediating influence of experientially acquired expertise. The study focuses on the extent to which expertise mediates between experience and firm performance, and on the relationship between distinct types of experience and distinct forms of expertise. The analyses are based on data collected from a sample of 43 owner-founded and operated biotechnology and telecommunication firms     

Elastooptical properties of SiON layers in an integrated opticalinterferometer used as a pressure sensor

This work presents the design and realization of an integrated optical pressure sensor, which is based on the photoelastic birefringence of thin SiO₂ and SiON layers. The advantage of this well known and controlled silicon technology is that optical and electronic circuits as well as micromechanics can be integrated on the same substrate. The sensor is made of a monomode striploaded Mach-Zehnder interferometer, which is placed on a silicon membrane as the pressure sensitive region. The detector is integrated into the silicon substrate, because a wavelength below 1 μm(He-Ne laser source: 632.8 nm) is used. Experimental and theoretical results of the sensor response are presented that demonstrate that efficient sensors can be designed and fabricated and that the TM-polarization gives the higher sensitivity     

Data communications using ATM: architectures, protocols, andresource management

The introduction of ATM is being propelled by the need for fast data communications in public and private networks. What is needed is a clear picture of protocol architectures and traffic characteristics of the various applications to be supported both now and in the future. The authors discuss ATM network architectures with special focus on the support of connectionless LAN interconnection and show which benefits can be obtained from the introduction of a connectionless server in an ATM network. They outline issues related to the use of existing protocols when ATM networks are introduced and show which protocol complexities have to be handled by gateways and servers, again using the example of connectionless LAN interconnection. Having presented network and protocol architectures the issue of data communication in ATM, resource allocation, is treated