Regulation of natriuretic peptide (urodilatin) release in a human kidney cell line

1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic beta-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with L-glutamate. This enzyme required pyridoxal 5'-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25 degreesC and had Kms of 9.1 mM for L-glutamate and 4.5 mM for DL-ASA. DABA acetyltransferase catalyzed acetylation of DABA to gamma-N-acetyl-alpha,gamma-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20 degreesC in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15 degreesC in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0. 77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30 degreesC.     

The use and effectiveness of analogical instruction in diverse secondary content classrooms.

The purpose of these studies was to explore the use of analogies while teaching important concepts in secondary content classrooms containing students of diverse abilities. Various research methodologies were used to determine the effects of an analogically based routine on student learning and the effects of training on teacher use of the routine. Measures included students' knowledge of concepts, the numbers and types of analogies teachers used, teacher use of elements of the instructional routine, and teacher and student satisfaction. Teacher use of the routine led to increased student retention and expression of information. In addition, teachers easily learned the routine and used considerably more analogies to instruct concepts after they became familiar with the routine. Teachers indicated that they were satisfied with the routine; students were less satisfied with the routine than were the teachers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

提高用于高温环境和电负载的薄膜电阻的性能

可提高焊点在高工作温度下可靠性的无铅合金非常适用于汽车电子或特殊应用。薄膜电阻的端接和结构采用了一些最新的增强技术,使设计者能够使用这些大批量市场的器件,加上最新的焊锡配方,用更低的成本组装出在恶劣环境下工作的设备。     

Use of computed radiography in the study of an historic painting

The authors demonstrate the use of radiography in the investigation of an historic painting and describe the potential benefits of computed radiography compared with conventional screen-film radiography. The subject for the comparison was a 16 x 19-foot oil-on-canvas painting, Scipio Africanus Freeing Massiva, by Giovanni Battista Tiepolo. Radiographs of the painting were obtained by using a portable, industrial radiographic unit and both conventional screen-film and photostimulable phosphor plate cassettes. For this investigation, computed radiography had a number of advantages over screen-film radiography, largely due to its wider dynamic range and its capabilities for enhancing the digital images with image processing tools such as magnification, edge enhancement, colorization, and airbrushing. The ability to electronically combine images from the large painting into a single composite image file was extremely valuable, as this technique was much less cumbersome and resulted in much higher quality composite images than could be achieved with conventional radiography. An additional advantage of computed radiography includes the capability to easily archive and transmit these images in a digital format for subsequent review.     

Integrated Circuits for Broad-Band Communications Systems

Integrated circuits for broad-band communication systems which enable broad-band communication between subscribers require LSI's with a performance concerning speed, complexity, and power dissipation which cannot be fully met by present semiconductor technologies. The requirements for coders and decoders, line transmission circuits, and broad-band switching network elements depend upon the system concept chosen. For one chosen system concept, these requirements are derived. By using a representative model for the development of the demand, characteristic curves for the demand of subscriber-line circuits and for central unit elements are resulting. From these curves the optimum semiconductor technologies, complexities, and design strategies are derived. It can be assumed that the results are rather independent of variations of system concept and introduction models.     

Bersten eines Hochdruckbehälters während einer Wasserdruckprobe. Gedanken zur Auslegung von Hochdruckapparaten insbesondere hinsichtlich der Sprödbruchsicherheit

Rupture of a High Pressure Vessel During Water Proof Test A high pressure vessel (inside diameter 300 mm) made from a French high strength steel with a yield strength of about 1100 N/mm² and a tensile strength of about 1300 N/mm² catastrophically ruptured during a water proof test at a pressure of 2900 bar. According to the technical rules the postulated test pressure was 3250 bar. At both ends the vessel was closed with screw caps. It ruptured in the upper part vertically to the axis in the first pitch of screw thread. The reason for this damage was found out by metallurgical and fracture mechanical investigations: By few load cycles caused by operation of the vessel, some 50–100 μmUm deep cracks were found. These small cracks became unstable during the last water proof test and are responsible for spontaneous spreading of the fracture. Numerous additional investigations showed the applied steel is proper for fabrication of high pressure vessels if being in the favourable condition. Te correct temperature for tempering does influence the properties of the steel significantly. With a constant safety factor regarding to yield strength and bursting pressure, the occurance of a brittle fracture increases with higher yield strength steels: The fracture toughness will become lower and therefore the critical crack length will become smaller. Possibly the critical crack depth becomes so small that the cracks cannot be found by nondestructive testing. Consequently it is more favourable to reduce the numerical safety against yield strength in order to obtain higher safety against the occurance of brittle fractures.     

Zur Abweichungsanalyse im operativen, modellgestützten Controlling

Systems of economic ratios are very important in the field of operative controlling. Functional equations of economic quantities may be analyzed by comparing actual current values of these variables with planned values or values of a previous period using methods of deviation analysis. In this paper different methods of deviation analysis are compared. They are based on conditions, which should be satisfied by methods used to determine the effects on a depending quantity caused by the change of its components. In some aspects these conditions are different from conditions for methods of deviation analysis used in cost accounting. Based on an approximation of the temporal change of economic quantities a new method of deviation analysis is developed. This concept satisfies all conditions formulated at the beginning of the paper.     

The use and effectiveness of a comparison routine in diverse secondary content classrooms.

The purpose of this investigation was to explore teachers' use and effectiveness of a comparison routine to help students understand comparisons of important content information in secondary content classes containing students of diverse ability. Various research methodologies, including single-subject and large-group experimental designs, were used. Measures included students' knowledge of information involving comparisons, the numbers and types of comparisons teachers used, teachers' use of the instructional routine, and teachers' and students' satisfaction with the instruction. Use of the routine led to significantly better retention and expression of information by students in the experimental condition compared with students participating in a traditional lecture-discussion format. Teachers easily learned the routine, delivered more complete instruction, and used the routine to teach regularly scheduled curricula. Teachers indicated that they were satisfied with the routine; in general, students were neither satisfied nor dissatisfied with the routine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A role for CD4 in peripheral T cell differentiation

A rapid method for the simultaneous determination of cholesterol and its oxidation products as well as alpha-to-copherol and tocopherolquinone in brain subcellular fractions is described. The samples are saponified and extracted with hexane. It is not necessary to remove cholesterol in the sample before analyzing for oxysterols. The hexane extract can be used for the assay of cholesterol compounds by capillary gas chromatography and tocopherol compounds by liquid chromatography using a procedure reported previously. Oxidation of synaptosomes by a mixture of Fe2+ plus ascorbate resulted in the production of 7-keto-, 7 alpha-hydroxy-, 7 beta-hydroxy-, and 5 alpha, 6 alpha-epoxycholesterols. The identities of these products were confirmed with gas chromatography/mass spectrometry. Cholesterol oxidase treatment did not result in the formation of any of the above compounds. Thus the types and amounts of the products of oxidation of cholesterol were dependent upon the oxidizing agent. Extraction of the oxysterols under milder conditions without saponification using sodium dodecyl sulfate cannot be used since such treatment results in low recovery of oxysterols. Oxidation of synaptosomes by low concentrations of ferrous iron and ascorbate resulted in (i) low levels of oxidation of cholesterol which could be followed by estimating the production of oxysterols and (ii) oxidation of a substantial percentage of alpha-tocopherol. The proposed procedure will be useful in monitoring the oxidation of small quantities of membrane cholesterol in vitro.