Mobile velocity-controlled respirometer: description and performance capabilities

An apparatus modeled after the Scram respirometer designed by Corcoran is described in terms of design, specifications and performance capabilities. The results with the use of this apparatus in a study of 14 able-bodied adults of five controlled walking speeds are compared to those of a similar study previously reported by Corcoran and Brengelmann. Oxygen consumption (ml O2/kg body wt/min) increases proportionately to the square of the velocity of walking. Results of the two investigations are parallel, although the present report demonstrates a greater male-female difference at all speeds. Uses and limitations of the apparatus are considered.     

Taxonomic importance of fermentation balances of Enterobacteriaceae (author''s transl)

Fermentation balances have been studied on 66 strains from 9 taxa of Enterobacteriaceae. In addition, 6 strains of Aeromonas have been investigated. Among these fermentation balances, 7 types could be distinguished. It was shown, that the taxa of Enterobacteriaceae differed with respect to the balance types involved. This is true especially for VP-positive taxa. For example, Hafnia, the Klebsiella-Enterobacter-Serratia group, Enterobacter cloacae and Erwinia are to some extend characterized by different balance types. The groups of Enterobacteriaceae with plain acid fermentation are apperently more homogenous with respect to fermentation balances. Balances are, however, not suited for classification, because no balance type turned out to be absolutely group specific. The fermentation balances of our strains of Aeromonas are closely related to the acid-type balances of Enterobacteriaceae. A numerical classification of the data showed, that this method is most potent in sorting multivariate data. A basic agreement of both techniques, the subjective and the numerical subdivision, was found. The first one, however, tends to overemphasize differences among the types. A comparison between the quantitative data of fermentation balances and the corresponding diagnostic tests (MR, VP, Gas) gives information on the reliabiity of the latter.     

NDT of shape adaptive structures

Health monitoring of smart structures is important for maintaining their performance. Damage may be caused by electrical or mechanical overload, or by ageing. We indicate methods that allow the detection and characterisation of defects in a non-destructive way: impedance spectroscopy, dynamic thermography and interferometry. Examples are shown for a model sample and an industrial structure.     

Lamb waves for non-contact fatigue state evaluation of composites under various mechanical loading conditions

Methodologies for non-destructive evaluation of mechanically induced fatigue in fibre reinforced polymers are discussed. Specimens made of non-crimp glass fabric are fatigued using three different load ratios (tension–tension, tension–compression, and compression–compression). The investigation involves two loading directions (0° and 90°) of the quasi–orthotropic composite. Based on mode conversion of air-coupled ultrasound to Lamb waves, variation in a₀-mode velocity is measured in a non-contact and single-sided access configuration. The velocity measurements are performed within and outside the servo-hydraulic test rig used for inducing fatigue damage. Formation of cracks monitored in the transparent composite results in degradation of stiffness observed by the test rig. Decrease in a₀-mode velocity caused by fatigue is shown to correlate closely with stiffness degradation for all loading ratios and directions. The correlation is studied by calculating a₀-mode velocities from single-ply properties whose stiffness degradation was determined using the observed crack densities and a finite element based model.     

Microstructured ZnO coatings combined with antireflective layers for light management in photovoltaic devices

We describe microstructured ZnO coatings that improve photovoltaic (PV) device performance through their antireflective properties and their tendency to scatter incoming light at large angles. In many PV devices, reflection from the transparent conductive top contact significantly degrades performance. Traditional quarter‐wave antireflective (AR) coatings reduce surface reflection but perform optimally for only a narrow spectral range and incident illumination angle. Furthermore, in some types of devices, absorption far from the junction increases the rate of recombination, and light management strategies are required to remedy this. The randomly patterned, microstructured ZnO coatings described in this paper, formed via a simple wet etch process, serve as both an AR layer with superior performance to that of a thin film AR coating alone as well as a large angle forward scatterer. We model formation of the coatings and evaluate their AR properties. When combined with a traditional quarter‐wave MgF₂ coating, these microstructured ZnO coatings increase short circuit currents of example Cu(In,Ga)Se₂ (CIGS) devices by over 20% in comparison to those of uncoated devices at normal incidence. A similar improvement is observed for illumination angles of up to 60°. While demonstrated here for CIGS, these structures may prove useful for other PV technologies as well. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Progress in Photovoltaics: Research and Applications Published by John Wiley & Sons Ltd.     

The aerodynamic cost of flight in the short-tailed fruit bat (Carollia perspicillata): comparing theory with measurement

Aerodynamic theory has long been used to predict the power required for animal flight, but widely used models contain many simplifications. It has been difficult to ascertain how closely biological reality matches model predictions, largely because of the technical challenges of accurately measuring the power expended when an animal flies. We designed a study to measure flight speed-dependent aerodynamic power directly from the kinetic energy contained in the wake of bats flying in a wind tunnel. We compared these measurements with two theoretical predictions that have been used for several decades in diverse fields of vertebrate biology and to metabolic measurements from a previous study using the same individuals. A high-accuracy displaced laser sheet stereo particle image velocimetry experimental design measured the wake velocities in the Trefftz plane behind four bats flying over a range of speeds (3–7 m s⁻¹). We computed the aerodynamic power contained in the wake using a novel interpolation method and compared these results with the power predicted by Pennycuick''s and Rayner''s models. The measured aerodynamic power falls between the two theoretical predictions, demonstrating that the models effectively predict the appropriate range of flight power, but the models do not accurately predict minimum power or maximum range speeds. Mechanical efficiency—the ratio of aerodynamic power output to metabolic power input—varied from 5.9% to 9.8% for the same individuals, changing with flight speed.     

Sexual arousal in male pigtailed monkeys (Macaca nemestrina): Effects of serial matings by two males.

Examined male sexual arousal in 4 vasectomized male and 3 intact multiparous female pigtailed monkeys with the postejaculatory interval (PEI) used as the dependent variable. 12 paired trials were conducted in which a male and female copulated, the 1st male was removed and a 2nd male was or was not allowed to copulate with the female, and the 1st male was again permitted to copulate with the female. In male–female pairs, the PEI was shortened by 60% of normal (control) values if the male observed another male copulating with his female partner. Results demonstrate that the normal PEI is not an absolute male refractory period; males are capable of copulating sooner, and they will do so when presented with certain behavioral stimuli. A long PEI may prevent males from disrupting their own plugs prematurely, whereas a short PEI may result from a premature disruption of the plug by another male. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential induction of prehepatic and hepatic metabolism of verapamil by rifampin

Cytochrome P450 (CYP) enzymes, which metabolize numerous drugs, are expressed both in liver and in extrahepatic tissues. CYP3A4 for example is present and inducible by rifampin in epithelial cells of the gastrointestinal tract. It has been shown that such prehepatic metabolism contributes substantially to total clearance of CYP3A4 substrates (e.g., cyclosporine) before and even more pronounced during enzyme induction. We examined the effect of enzyme induction on prehepatic and hepatic metabolism of the model compound R/S-verapamil after simultaneous oral and intravenous administration using a stable isotope technology. This approach allows us to exclude intraindividual day-to-day variability and is therefore suitable to quantitatively assess prehepatic extraction of high-clearance drugs. Moreover, because verapamil is administered as a race-mate with the S-enantiomer being preferentially metabolized, we investigated the influence of induction on stereoselectivity of prehepatic and hepatic metabolism. Eight male volunteers received 120 mg of racemic verapamil bid for 24 days. Rifampin (600 mg daily) was given from day 5 to day 16. Systemic clearance and bioavailability of the verapamil enantiomers were determined by coadministering deuterated verapamil intravenously on day 4, on day 16, and on day 24. Effects of verapamil on atrioventricular conduction after oral and intravenous (iv) administration were assessed by measuring the maximum PR-interval prolongation Rifampin increased the systemic clearance of the active S-verapamil 1.3-fold (P < .001). In contrast, rifampin increased the apparent oral clearance of S-verapamil 32-fold (P < .001) and decreased its bioavailability 25-fold (P < .001), with partial recovery after rifampin withdrawal (P < .01). With rifampin, the effect of oral verapamil on atrioventricular conduction was nearly abolished (P < .01), whereas no significant changes were observed after intravenous administration. Induction caused a considerable reduction of stereoselectivity after both intravenous and oral administration (P < .001). Rifampin altered the pharmacokinetics and the pharmacological effects of verapamil to a much greater extent after oral administration compared with intravenous administration. These data clearly indicate that prehepatic metabolism of verapamil (presumably in the gut wall) is preferentially induced compared with hepatic metabolism and that stereoselectivity of verapamil metabolism is affected by induction.