The controlled TUR: a new method for the measurement of intraoperative blood-loss during TUR (author's transl)

The measurement of intraoperative blood-loss during TUR is concerned as a compulsory procedure for this kind of operation. After testing so far known methods for measuring blood-volume in blood-water-mixtures and demonstrating greater disadvantages of these methods, we developed a new photometer, which allows an immediate and exact estimation of the blood-loss. We compared this new method with other also exact but more complicated methods, had laboratory tests and tests in the daily operative routine and excluded possible mistakes.     

FE simulations of granular material with a given frequency distribution of voids as initial condition

A hypoplastic law is used for the FE simulations of two model tests with sand. In both model tests localization is observed. It is shown that void ratio scattering at initial state of the numerical simulations is of primary importance in order to model localization. A simple exponential frequency distribution, which is dependent of the sand density yields realistic results.     

Converting blood coagulation factor IXa into factor Xa: dramatic increase in amidolytic activity identifies important active site determinants

The coagulation factors IXa (fIXa) and Xa (fXa) share extensive structural and functional homology; both cleave natural substrates effectively only with a cofactor at a phospholipid surface. However, the amidolytic activity of fIXa is 10(4)-fold lower than that of fXa. To identify determinants of this poor reactivity, we expressed variants of truncated fIXa (rf9a) and fXa (rf10a) in Escherichia coli. The crystal structures of fIXa and fXa revealed four characteristic active site components which were subsequently exchanged between rf9a and rf10a. Exchanging Glu219 by Gly or exchanging the 148 loop did not increase activity of rf9a, whereas corresponding mutations abolished reactivity of rf10a. Exchanging Ile213 by Val only moderately increased reactivity of rf9a. Exchanging the 99 loop, however, dramatically increased reactivity. Furthermore, combining all four mutations essentially introduced fXa properties into rf9a: the amidolytic activity was increased 130-fold with fXa substrate selectivity. The results suggest a 2-fold origin of fIXa's poor reactivity. A narrowed S3/S4 subsite disfavours interaction with substrate P3/P4 residues, while a distorted S1 subsite disfavours effective cleavage of the scissile bond. Both defects could be repaired by introducing fXa residues. Such engineered coagulation enzymes will be useful in diagnostics and in the development of therapeutics.     

Nanoindentation behavior of nanolayered metal-ceramic composites

Small-length scale multilayered structures are attractive materials due to their extremely high strength and flexibility, relative to conventional laminated composites. In this study, nanolayered laminated composites of Al and SiC were synthesized by DC/RF magnetron sputtering. The microstructure of the multilayered structures was characterized, and the mechanical properties measured by nanoindentation testing. The influence of layer thickness on Young’s modulus and hardness of individual and multilayers was quantified. An analytical model was used to subtract the contribution of the Si substrate, to extract the true modulus of the films. This paper was presented at the International Symposium on Manufacturing, Properties, and Applications of Nanocrystalline Materials sponsored by the ASM International Nanotechnology Task Force and TMS Powder Materials Committee on October 18–20, 2004 in Columbus, OH.     

Functional characteristics and radiation tolerance of AToM, thefront-end chip of BaBar silicon vertex tracker

The readout chip designed to process the microstrip signals in the BaBar Silicon Vertex Tracker (SVT), after being realized twice in a radsoft technology has been transferred into the final radhard process. So far the circuit has gone through four different radhard submissions, one aiming at providing a preliminary insight into the characteristics of the radhard chip, the other ones constituting pre-production and production runs. Chips from these submissions have undergone a thorough set of tests addressing functional aspects, noise parameters and effects of radiation on signal and noise behavior. The present paper discusses the results of these tests and describes the final version of the circuit which has been proven to successfully meet the experiment requirements     

Validating the accuracy of activity and rumination monitor data from dairy cows housed in a pasture-based automatic milking system

Behavioral observations are important in detecting illness, injury, and reproductive status as well as performance of normal behaviors. However, conducting live observations in extensive systems, such as pasture-based dairies, can be difficult and time consuming. Activity monitors, such as those created for use with automatic milking systems (AMS), have been developed to automatically and remotely collect individual behavioral data. Each cow wears a collar transponder for identification by the AMS, which can collect data on individual activity and rumination. The first aim of this study was to examine whether cow activity levels as reported by the AMS activity monitor (ACT) are accurate compared with live observations and previously validated pedometers [IceQube (IQ), IceRobotics, Edinburgh, UK]. The second aim of the study was to determine if the AMS rumination monitors (RUM) provide an accurate account of time spent ruminating compared with live observations. Fifteen lactating Holstein cows with pasture access were fitted with ACT, RUM, and IQ. Continuous focal observations (0600–2000 h) generated data on lying and active behaviors (standing and walking), as well as rumination. Activity recorded by live observation and IQ included walking and standing, whereas IQ steps measured cow movement (i.e., acceleration). Active behaviors were analyzed separately and in combination to ascertain exactly what behavioral components contributed to calculation of ACT “activity.” Pearson correlations (r_p) were computed between variables related to ACT, RUM, IQ, and live observations of behavior. A linear model was used to assess significance differences in the correlation coefficients of the 4 most relevant groups of variables. Significant but moderate correlations were found between ACT and observations of walking (r_p = 0.61), standing (r_p = 0.46), lying (r_p = −0.57), and activity (r_p = 0.52), and between ACT and IQ steps (r_p = 0.75) and activity (r_p = 0.58) as well as between RUM and observations of rumination (r_p = 0.65). These data indicate that ACT and RUM do reflect cow walking and rumination, respectively, but not with a high degree of accuracy, and lying cannot be distinguished from standing.     

A multicultural assessment of adolescent connectedness: Testing measurement invariance across gender and ethnicity.

Counselors, psychologists, and evaluators of intervention programs for youth increasingly view the promotion of connectedness as an important intervention outcome. When evaluating these programs, researchers frequently test whether the treatment effects differ across gender and ethnic or racial groups. Doing so necessitates the availability of culturally and gender-invariant measures. We used the Hemingway: Measure of Adolescent Connectedness to estimate the factor structure invariance and equality of means across gender and 3 racial/ethnic groups with a large sample of middle school adolescents. From a practical perspective, the 10-scale model suggested factor structure invariance across gender and racial or ethnic (i.e., African American, Caucasian, and Latina/o) groups of adolescents. However, tests for partial invariance revealed some group difference on the factor loadings and intercepts between gender and ethnic/racial groups. When testing for mean equivalence, girls reported higher connectedness to friends, siblings, school, peers, teachers, and reading but lower connectedness to their neighborhoods. Caucasians reported higher connectedness to their neighborhoods and friends but lower connectedness to siblings than African Americans and Latinos. African Americans reported the highest connectedness to self (present and future) but lowest connectedness to teachers. Latinos reported the lowest connectedness to reading, self-in-the-present, and self-in-the-future. Overall, this study reveals racial/ethnic and gender mean differences on several connectedness subscales and suggests the Hemingway subscales are, from a practical perspective, invariant across gender and ethnicity and therefore appropriate for most assessment and evaluation purposes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dosimetric calculations for uranium miners for epidemiological studies

Epidemiological studies on uranium miners are being carried out to quantify the risk of cancer based on organ dose calculations. Mathematical models have been applied to calculate the annual absorbed doses to regions of the lung, red bone marrow, liver, kidney and stomach for each individual miner arising from exposure to radon gas, radon progeny and long-lived radionuclides (LLR) present in the uranium ore dust and to external gamma radiation. The methodology and dosimetric models used to calculate these organ doses are described and the resulting doses for unit exposure to each source (radon gas, radon progeny and LLR) are presented. The results of dosimetric calculations for a typical German miner are also given. For this miner, the absorbed dose to the central regions of the lung is dominated by the dose arising from exposure to radon progeny, whereas the absorbed dose to the red bone marrow is dominated by the external gamma dose. The uncertainties in the absorbed dose to regions of the lung arising from unit exposure to radon progeny are also discussed. These dose estimates are being used in epidemiological studies of cancer in uranium miners.