Quantification of friction force reduction induced by obstetric gels

The objective of this study was to quantify the reduction of friction forces by obstetric gels aimed to facilitate human childbirth. Lubricants, two obstetric gels with different viscosities and distilled water, were applied to a porcine model under mechanical conditions comparable to human childbirth. In tests with higher movement speeds of the skin relative to the birth canal, both obstetric gels significantly reduced dynamic friction forces by 30-40% in comparison to distilled water. At the lowest movement speed, only the more viscous gel reduced dynamic friction force significantly. In tests modifying the dwell time before a movement was initiated, static friction forces of trials with highly viscous gel were generally lower than those with distilled water. The performed biomechanical tests support the recommendation of using obstetric gels during human childbirth. Using the presented test apparatus may reduce the amount of clinical testing required to optimize gel formulatio

Das Lagerstättengebiet Geyer

Die Monographie des Lagerstättengebietes Geyer bildet in räumlicher und inhaltlicher Hinsicht eine Fortsetzung und Ergänzung der 1994 veröffentlichten Monographie des Zinnerzlagerstättengebietes Ehrenfriedersdorf. Im Lagerstättengebiet Geyer lassen sich mehrere Lagerstättentypen unterscheiden. Verbreitet sind stratiforme Typen. Hierzu gehören Sulfiderzlager vom Typ Kiesgrube, die Bildungen der prävariszischen Geosynklinaletappe darstellen, und Skarnlager, die genetisch zum variszischen Mineralisationszyklus zählen. Unter den zinnführenden Strukturen erlangt der stockwerkartige metasomatische Strukturtyp im Endokontakbereich die größte Bedeutung. Gangförmige zinnerzführende Ausfüllungsstrukturen im Exokontakt sind in geringerer Intensität als im benachbarten Ehrenfriedersdorfer Revier verbreitet. Hydrothermale Gangstrukturen erlangen keine Lagerstättenbedeutung. Die in den Gängen auftretenden Mineralisationen lassen sich sowohl dem variszischen als auch dem postvariszisch-saxonischen Mineralisationszyklus zuordnen. Die Beschreibung der Lagerstätten und Vorkommen umfaßt die Kiesgrube Geyer (Sulfiderzlager), den Schurf 14/67 (Skarntyp), das Lagerstättengebiet Geyer SW (Skarntyp), die Zinnlagerstätte Geyer (Greisentyp), den Schurf 1/61 (Skarntyp und Gangtyp), das Revier Spitzberg mit dem Spitzberger Erbstolln sowie den Schürfen 2/68 und 2/69 (Skarntyp und Gangtyp), das Revier Geyer NO (Gangtyp) und Zinnseifen. Angaben zum Altbergbau und zu den Aufschlußverhältnissen stehen am Beginn jeder Lagerstättenbeschreibung. Es folgt eine lithostratigraphische Zuordnung der aufgeschlossenen metamorphen Schichtenfolge, eine kurze petrographische Charakterisierung der auftretenden magmatischen Gesteine und eine Beschreibung der tektonischen Elemente. Die eigentliche Lagerstättencharakteristik umfaßt Ausbildung, räumliche Position und Form der Erzkörper sowie Paragenese und Verteilungsgesetzmäßigkeiten. Die in den Aufschlüssen der ehem. SDAG Wismut angetroffene Uranvererzung, ihre tektonische und lithologische Kontrolle, wird mit beschrieben. Unter den bergbautechnischen Angaben nehmen die Ergebnisse von Aufbereitungsversuchen den größten Raum ein. Hydro- und ingenieurgeologische Fakten sowie Abbaumethoden finden nur stichwortartig Erwähnung. Unter bergwirtschaftlichen Angaben werden Bemusterungsmethoden, Bemusterungsergebnisse und, soweit möglich, Vorratszahlen mitgeteilt. Altlasten sind geogen und anthropogen bedingt. Von besonderer Bedeutung sind anthropogen bedingte Arsen-Anomalien im Boden (Hüttenwerke, Pochwerke). Verwahrung, Sanierung und Rekultivierung ehemals bergbaulich genutzter Flächen lassen sich im Lagerstättengebiet Geyer relativ problemlos lösen

Post-Operative Radiotherapy of the Rhabdomyosarcoma R1H of the Rat

Purpose. Post-operative radiotherapy (RT) is routinely applied in the treatment of several human tumours. The aim of the present study was to investigate the value of post-operative RT in a rat model

Biophilic Cities Are Sustainable, Resilient Cities

There is a growing recognition of the need for daily contact with nature, to live happy, productive, meaningful lives. Recent attention to biophilic design among architects and designers acknowledges this power of nature. However, in an increasingly urban planet, more attention needs to be aimed at the urban scales, at planning for and moving towards what the authors call “biophilic cities”. Biophilic cities are cities that provide close and daily contact with nature, nearby nature, but also seek to foster an awareness of and caring for this nature. Biophilic cities, it is argued here, are also sustainable and resilient cities. Achieving the conditions of a biophilic city will go far in helping to foster social and landscape resilience, in the face of climate change, natural disasters and economic uncertainty and various other shocks that cities will face in the future. The paper identifies key pathways by which biophilic urbanism enhances resilience, and while some are well-established relationships, others are more tentative and suggest future research and testing

Determination of the mixing ratio of a flowing gas mixture with self-actuated microcantilevers

Microcantilevers offer a wide range of applications in sensor and measurement technology. In this work cantilever sensors are used as flow sensors. Most conventional flow sensors are often only calibrated for one type of gas and allow an analysis of gas mixtures only with increased effort. The sensor used here is a cantilever positioned vertically in the flow channel. It is possible to operate the sensor in dynamic and static mode. In the dynamic mode the cantilever is oscillating. Resonance frequency, resonance amplitude and phase are measured. In static mode, the bending of the cantilever is registered. The combination of the modes enables the different measured variables to be determined simultaneously. A flow influences the movement behaviour of the sensor, which allows the flow velocity to be deduced. In addition to determining the flow velocity, it is also possible to detect different types of gas. Each medium has certain properties (density and viscosity) which have different effects on the bending of the sensor. As a result, it is possible to measure the mixing ratio of a known binary gas mixture and their flow velocity simultaneously with a single sensor. In this paper this is investigated using the example of the air–carbon-dioxide mixture

SERUM CONCENTRATIONS OF TNF-a AND ITS SOLUBLE RECEPTORS DURING PSYCHOTHERAPY IN GERMAN SOLDIERS SUFFERING FROM COMBAT-RELATED PTSD

Background: Changes in serum concentrations of tumor necrosis factor

Compensation mechanism in tumor cell migration: mesenchymal–amoeboid transition after blocking of pericellular proteolysis

Invasive tumor dissemination in vitro and in vivo involves the proteolytic degradation of ECM barriers. This process, however, is only incompletely attenuated by protease inhibitor–based treatment, suggesting the existence of migratory compensation strategies. In three-dimensional collagen matrices, spindle-shaped proteolytically potent HT-1080 fibrosarcoma and MDA-MB-231 carcinoma cells exhibited a constitutive mesenchymal-type movement including the coclustering of β1 integrins and MT1–matrix metalloproteinase (MMP) at fiber bindings sites and the generation of tube-like proteolytic degradation tracks. Near-total inhibition of MMPs, serine proteases, cathepsins, and other proteases, however, induced a conversion toward spherical morphology at near undiminished migration rates. Sustained protease-independent migration resulted from a flexible amoeba-like shape change, i.e., propulsive squeezing through preexisting matrix gaps and formation of constriction rings in the absence of matrix degradation, concomitant loss of clustered β1 integrins and MT1-MMP from fiber binding sites, and a diffuse cortical distribution of the actin cytoskeleton. Acquisition of protease-independent amoeboid dissemination was confirmed for HT-1080 cells injected into the mouse dermis monitored by intravital multiphoton microscopy. In conclusion, the transition from proteolytic mesenchymal toward nonproteolytic amoeboid movement highlights a supramolecular plasticity mechanism in cell migration and further represents a putative escape mechanism in tumor cell dissemination after abrogation of pericellular proteolysis