A new AC voltage standard

An AC voltage standard has been developed for the 10 Hz-1 MHz frequency range with basic accuracy of 37.5 p.p.m. The standard is programmable and twice as accurate as current calibrators. Unique circuitry used to achieve fast response and high frequency, high voltage capability is described. The AC voltage standard incorporates a novel solid-state thermal converter which uses proprietary concepts to speed up AC-DC conversion while maintaining broad bandwidth and high frequency response. Design concepts which reduce maintenance cost, automate calibration, and simplify precise traceable AC voltage measurements are also provided     

DNA index by flow cytometric analysis: an additional prognostic factor in advanced ovarian carcinoma without residual disease after primary operation

Prediction of duration of a patient's stay in the ICU after cardiac surgery is difficult. In 652 consecutive adult patients undergoing elective coronary artery bypass graft (CABG) surgery, we analysed prospectively preoperative and immediate postoperative variables thought to influence duration of stay in the ICU. With univariate analysis, we found that age, preoperative left ventricular ejection fraction, bypass time, aortic cross-clamp time, blood transfusions and the number of inotropic agents administered in the immediate postoperative period (for at least 6 h) were significant correlates of duration of stay in the ICU. However, logistic regression analysis showed that the number of inotropes was the most important determinant of stay in the ICU, with an overall prediction accuracy of 94.8%. The main cause of prolonged stay in the ICU (more than 2 days) was low cardiac output syndrome. We conclude that analysis of perioperative variables enhanced our ability to accurately predict duration of stay in the ICU in cardiac surgery patients. The number of inotropic agents administered during the first 6 h after operation was the most important determinant of duration of stay in the ICU.     

REM sleep parasomnia

The parasomnias consist of a heterogenous group of sleep behaviour disorders with different etiologies and various symptomatologies. By employing polysomnography and the simultaneous video recording of behaviour during sleep, it is possible to associate behavioral disturbances during sleep with specific sleep stages. In the present case study, a patient with a REM (rapid eye movement) sleep behaviour disorder is discussed. This rare form of parasomnia is characterized by motor enactment of vivid and striking dreams. Underlying disease in the present case involved bilateral lacunar ischemic infarcts in the brain stem. Under the combined psychotropic medication of carbamazepine and amitriptyline, the behaviour disorder during REM sleep remitted markedly.     

A new optically sensed thermal element for precise AC-DC conversion

An optically sensed isothermal differential thermal converter has been reduced to practice using a commercially available optical infrared pyrometer. Eliminating the conventional bimetallic thermocouples avoids draining thermal energy from the heater, reduces the Thomson effect error, and minimizes shunt paths along the heater which bypass higher frequency signal components. The optically sensed thermal element provides the potential for greater accuracy over a wide frequency range, faster response time, and improved dynamic range over conventional wire or planar thermal elements using Seebeck, thermoresistive or semiconductor temperature sensing     

Anwendung der Fließgelenktheorie auf Baugruben

Application of plastic design to retaining walls. Design approaches that take the occurrence of plastic hinges into account are generally known as a smart way to determine the ultimate load of statically indeterminate systems. The ultimate state is reached, when the hole system or several parts of it become kinematical. Thus this kind of design approach takes advantage of the plastic reserve of the cross-section and of the static system. The application of plastic design to retaining walls leads to a few interesting questions. There are several failure mechanisms that arise from the following failure types and combinations of them: plasticizing of the sheet pile wall – plasticizing of the anchorage or support – failure of the area of soil resistance. Further on it's not clear how the plasticizing of the system shall be induced, because unlike in structural analysis the soil is not only a load in the form of the earth pressure acting on the retaining wall but also a structural element. Thus it's the often described characteristic of geotechnics that has to be taken into account. There are six approaches introduced, of which two are further examined by the finite element method. The first approach consists of the reduction of the plastic bending moment resistance of the sheet pile until plastic hinges occur. The idea of the second approach is to increase the water pressure incremental. The calculations show, that the earth pressure is redistributing with the increasing displacement of the sheet pile wall in dimensions that are generally greater than covered by the recommendations of EAB (2006) and EAU (2004). This could lead to an underestimation of the supporting force. The EAB (2006) allows the plastic design of sheet pile walls if certain conditions are considered. The EAU (2004) does not include such recommendations yet.     

Comparison of fluorescence in situ hybridization with flow cytometry and static image analysis in ploidy analysis of paraffin-embedded prostate adenocarcinoma

Nuclear DNA ploidy has been shown to have an important prognostic association for patients with adenocarcinoma of the prostate. Flow cytometry and static image analysis are ploidy methods that have been used in prostate carcinoma. Fluorescence in situ hybridization (FISH) using chromosome-specific probes can be used to evaluate the ploidy of interphase nuclei. In this study FISH was compared with flow cytometry and static image analysis in determining ploidy in paraffin-embedded tissue from 34 prostatic adenocarcinomas. Ploidy status using FISH was determined by enumerating centromeres of two chromosomes (8 and 12) by use of directly-labeled alpha-satellite DNA probes in isolated whole nuclei obtained by the Hedley technique. All three methods identified 11 of 34 cases as diploid and 17 of 34 cases as nondiploid (82% concordance). Six cases were discordant; two cases had discrepant results by each method. Ploidy classification as determined by FISH had an 88% concordance with ploidy classification by either flow cytometry or static image analysis. In conclusion, FISH was found to be a sensitive method of ploidy analysis in isolated paraffin-embedded nuclei from prostate adenocarcinomas. When the chromosomes commonly involved in aneuploidy have been identified in prostate adenocarcinoma, FISH has the potential to provide greater sensitivity for aneuploidy detection compared with currently available methods.     

Alpha-1-antitrypsin phenotypes among patients with intracranial aneurysms

A deficiency of alpha 1-antitrypsin has been implicated in the development of arterial aneurysms, including intracranial aneurysms. The authors determined the prevalence of alpha 1-antitrypsin deficiency of different phenotypes in 100 consecutive patients with intracranial aneurysms and compared the distribution of alpha 1-antitrypsin phenotypes to that in the general population (904 people). The study population consisted of 44 men and 56 women with a mean age of 52 years (range 15-81 years). The heterozygous alpha 1-antitrypsin deficiency states (PiMS and PiMZ) were more common in patients (16%) than in the general population (7%), providing an odds ratio of 2.56 (95% confidence interval (CI) 1.32-4.75; p = 0.005). In addition, one patient (1%) was homozygous for the deficient allele (PiZZ) compared to an expected number of 0.015, providing an odds ratio of 67.0 (95% CI 2.0-363.3; p = 0.015). These findings lead the authors to suggest that the heterozygous and homozygous alpha 1-antitrypsin deficiency states are genetic risk factors for the development of intracranial aneurysms.