Shuttle navigation status

Shuttle navigation which is the determination of Orbiter position, velocity, and attitude and associated effort, together with guidance, flight control, consumables, and systems management, is required for classical navigation. Position and velocity propagation requires the measurement or modeling of the gravitational, aerodynamic, and rocket engine forces acting on the vehicle. Position and velocity determination is performed or observations of the distance to external features, the rate of change, and the direction toward the feature. Onboard state propagation is more often the mode of state knowledge maintenance, since the ability to determine position and velocity using such observations is limited. An overview of Shuttle nevigation is presented

Fabrication of hemispherical opposed self- acting gas bearings for the third-generation gyroscope

Fabrication of hemispherical opposed self-acting gas bearings for gyroscope

Sputter etching of hemispherical bearings

Technique was developed for fabricating three dimensional pumping grooves on gas bearings by sputter etching. Method eliminates problems such as groove nonuniformity, profile, and finish, which are associated with normal grooving methods

Vibrotactile sensitivity in active touch: effect of pressing force

An experiment was conducted to study the effects of force produced by active touch on vibrotactile perceptual thresholds. The task consisted in pressing the fingertip against a flat rigid surface that provided either sinusoidal or broadband vibration. Three force levels were considered, ranging from light touch to hard press. Finger contact areas were measured during the experiment, showing positive correlation with the respective applied forces. Significant effects on thresholds were found for vibration type and force level. Moreover, possibly due to the concurrent effect of large (unconstrained) finger contact areas, active pressing forces, and long duration stimuli, the measured perceptual thresholds are considerably lower than what previously reported in the literature

Chirurgische Therapiestrategien beim Ösophagus- und Magenkarzinom

Zusammenfassung: Diese Übersichtsarbeit hat zum Ziel, die aktuellen chirurgischen Strategien bei der Behandlung des Ösophagus- und Magenkarzinoms zusammenzufassen. Neben den etablierten Standardverfahren wird auf die limitierten Resektionen bei Frühkarzinomen und den Stellenwert der Chirurgie im multimodalen Behandlungskonzept bei lokal fortgeschrittenen T3/4-Tumoren eingegangen. Das Plattenepithelkarzinom und das Adenokarzinom (Barrett-Karzinom) der Speiseröhre werden aufgrund der unterschiedlichen Pathogenese und Tumorbiologie sowie differenzierter unterschiedlicher Vorgehensweisen separat dargestellt. Aufgrund der überwiegend distalen Lokalisation der Barrett-Karzinome ist eine Abgrenzung zu den echten Kardiakarzinomen und Tumoren, die im Magen ihren Ursprung nehmen und die distale Speiseröhre infiltrieren, erforderlich. Basierend auf der Klassifikation nach Siewert wird das Barrett-Karzinom deshalb zusammen mit den so genannten Adenokarzinomen des ösophagogastralen Übergangs (AEG) behandelt. Für die Weiterentwicklung der chirurgischen Therapiestrategien beim Magenkarzinom haben sich die asiatischen, insbesondere japanischen und südkoreanischen Kollegen große Verdienste erworben. Moderne, dort entwickelte, aber noch nicht in der westlichen Welt etablierte Strategien werden neben den Standardverfahren gebührend berücksichtigt. Für alle diese Tumoren gilt, dass die chirurgische Therapie ein elementarer Bestandteil im Rahmen eines kurativen Behandlungskonzepts ist. Sie ist aber differenzierter und Teil eines komplexen interdisziplinären Algorithmus; deshalb ist eine weitere Spezialisierung zum Wohle der Patienten ratsa

Schlüsselfaktoren der Mitgliederbindung im Wirtschaftsverband

Wirtschaftsverbände können ihre Mitgliederbasis am besten dadurch stabilisieren, indem sie sich auf ihre Kernaufgabe konzentrieren, für die sie ursprünglich gegründet wurden, und darüber hinaus eine lebendige Austauschplattform bereitstellen. Das zeigen Untersuchungen bei zwei Schweizer Verbänden, dem Ausbildungsverband flexo suisse und dem Berufsverband Baukader Schweiz. Die beiden Studien bestätigen zudem die Vermutung, dass zusätzlichen Leistungsangeboten vom Mitgliederstandpunkt aus eine deutlich geringere Rolle zukommt, obwohl aktuelle Bestrebungen häufig auf eine Erweiterung des Dienstleistungsspektrums über eine Ausweitung von Individualleistungen gerichtet sind

Secretory apparatus assessed by analysis of pancreatic secretory stress protein expression in a rat model of chronic pancreatitis

Secretory stress proteins (SSP) are a family of proteins including isoforms of pancreatitis-associated protein (PAP) and pancreatic stone protein (PSP/reg). In vitro exposure to trypsin results in the formation of insoluble fibrillar structures. SSP are constitutively secreted into pancreatic juice at low levels. The WBN/Kob rat is a model for chronic pancreatitis, displaying focal inflammation, destruction of the parenchyma and changes in the architecture of the acinar cell; the synthesis and secretion of SSP are also increased. We have investigated the secretory apparatus by SSP immunohistochemistry at the light- and electron-microscopical (EM) levels. Immunocytochemistry of PSP/reg in Wistar control rats reveals low levels, with individual acinar cells exhibiting high immunoreactivity in zymogen granules. PAP is not detectable. In the WBN/Kob rat, PSP/reg and PAP immunoreactivity is markedly increased. Double immunofluorescence for PSP/reg and PAPI or II demonstrates that these proteins colocalize to the same cell. Acinar cells change their secretory architecture by fusion of zymogen granules and elongation of the fused organelles. The immunogold technique has demonstrated an increase of SSP in zymogen granules in WBN/Kob rats. PSP/reg-positive zymogen granules fuse to form elongated structures with fibrillar contents. An extensive PSP/reg-positive fibrillar network is established in the cytosol. Extracellular fibrils have been observed in several ductules. Thus, SSP-derived fibrils form concomitantly with acinar damage in the WBN/Kob rat. Based on the known tryptic cleavage site of SSP, the in vivo generation of fibrils is presumably the result of premature trypsin activatio

Utility of Routine Versus Selective Upper Gastrointestinal Series to Detect Anastomotic Leaks After Laparoscopic Gastric Bypass

Background: In up to 4% of laparoscopic Roux-en-Y gastric bypass (LRYGB) procedures, anastomotic leaks occur. Early detection of gastrointestinal leakage is important for successful treatment. Consequently, many centers advocate routine postoperative upper gastrointestinal (UGI) series. The aim of this study was to determine the utility of this practice after LRYGB. Methods: Eight hundred four consecutive patients undergoing LRYGB from June 2000 to April 2010 were analyzed prospectively. The first 382 patients received routine UGI series between the third and fifth postoperative days (group A). Thereafter, the test was only performed when clinical findings (tachycardia, fever, and drainage content) were suspicious for a leak of the gastrointestinal anastomosis (group B; n = 422). Results: Overall, nine of 804 (1.1%) patients suffered from leaks at the gastroenterostomy. In group A, four of 382 (1%) patients had a leak, but only two were detected by the routine UGI series. This corresponds to a sensitivity of 50%. In group B, the sensitivity was higher with 80%. Specificities were comparable with 97% and 91%, respectively. Routine UGI series cost only 1.6% of the overall costs of a non-complicated gastric bypass procedure. With this leak rate and sensitivity, US $86,800 would have to be spent on 200 routine UGI series to find one leak which is not justified. Conclusions: This study shows that routine UGI series have a low sensitivity for the detection of anastomotic leaks after LRYGB. In most cases, the diagnosis is initiated by clinical findings. Therefore, routine upper gastrointestinal series are of limited value for the diagnosis of a lea

A tool for predicting the dynamic response of biotrickling filters for VOC removal

This article presents the development of a MATLAB® computer program to simulate the performance of biotrickling filters. Since these filters behave differently during spraying and nonspraying cycles, the presented simulation tool is built on top of a mathematical description of each situation. The resulting variable-structure model is then used as the basis for simulation experiments. The model presented herein represents the first attempt to take into account the variable spraying pattern usually found in industrial installations. Overall, the software is flexible and easy to use, allowing the user to specify the emission concentration pattern, the gas concentration pattern, as well as the spraying cycle periods for up to two different emission patterns per day. The model is able to predict experimental data from a biotrickling filter treating isopropanol under intermittent conditions of loading and spraying. Simulation examples are then provided to study the effect of variable inlet concentrations and gas flow rates