The Acridine Orange test: a clinically relevant screening method for sperm quality during infertility investigation?

To determine the clinical usefulness of Acridine Orange (AO) staining of spermatozoa as a screening test for the evaluation of semen quality during basic infertility investigation, semen smears from 103 randomly chosen males of subfertile couples were examined. The median duration of infertility was 4.5 years (range 1-15) and the median age was 33 years (range 21-43). The outcome of AO staining ranged from 5 to 81%, with a median of 24%, green fluorescent spermatozoa. Results were not significantly related to the parameters of semen analysis (sperm count, motility, standard morphology, viability, pH and volume, as well as fructose concentration and number of found cells) or to local sperm antibody testing and semen cultures. Fluorescence after AO staining was also not related to sperm functional capacity (evaluated using sperm-mucus interaction tests in vitro and in vivo), or the medical history of the patient. No significant differences in the AO test outcome were seen in patients with explained and unexplained infertility, or with regard to subsequent fertility [with a median value of 21% (range 5-46) green fluorescence in the fertile group, compared with a median value of 28% (range 9-81) green fluorescence in the other men]. The results of this prospective study indicate that under the usual conditions of conception, the AO test is not clinically useful as a screening procedure to determine semen quality during basic infertility investigation.     

Device performance of transistors with high-/spl kappa/ dielectrics using cross-wafer-scaled interface-layer thickness

A technique has been developed to fabricate transistors using a continuously scaled 0-2.5-nm SiO/sub 2/ interface layer between a silicon substrate and high-/spl kappa/ dielectric, on a single wafer. The transistor results are promising with good mobility values and drive current. The slant-etching process has no detrimental effect on the electrical characteristics of the Si/SiO/sub 2/ interface. This technique provides a powerful tool in examining the effect of the process variations on device performance.     

Robust segmentation of tubular structures in 3-D medical images by parametric object detection and tracking

We present a novel approach to the coarse segmentation of tubular structures in three-dimensional (3-D) image data. Our algorithm, which requires only few initial values and minimal user interaction, can be used to initialize complex deformable models and is based on an extension of the randomized hough transform (RHT), a robust method for low-dimensional parametric object detection. Tubular structures are modeled as generalized cylinders. By means of a discrete Kalman filter, they are tracked through 3-D space. Our extensions to the RHT are a feature adaptive selection of the sample size, expectation-dependent weighting of the input data, and a novel 3-D parameterization for straight elliptical cylinders. Experimental results obtained for 3-D synthetic as well as for 3-D medical images demonstrate the robustness of our approach w.r.t. image noise. We present the successful segmentation of tubular anatomical structures such as the aortic arc and the spinal cord.     

On the Precision in Estimating the Location of Edges and Corners

Recently, in Rohr [13], we analyzed the systematiclocalization errors introduced by local operators for detectinggrey-value corners. These errors are inherently due to thedifferential structure of the operators and, in general, areenlarged by discretization and noise effects. Here, we take thestatistical point of view to analyze the localization errorscaused by noisy data. We consider a continuous image model thatrepresents the blur as well as noise introduced by an imagingsystem. In general, the systematic intensity variations arenonlinear functions of the location parameters. For this modelwe derive analytic results stating lower bounds for the locationuncertainty of image features. The lower bounds are evaluatedfor explicit edge and corner models. We show that the precisionof localization in general depends on the noise level, on thesize of the observation window, on the width of the intensitytransitions, as well as on other parameters describing thesystematic intensity variations. We also point out that theuncertainty lower bounds in localizing these image features canin principle be attained by fitting parametric models directlyto the image intensities. To give an impression of theachievable accuracy numerical examples are presented.     

Generation and Quantification of Ultrafine Particles through Terpene/Ozone Reaction in a Chamber Setting

Terpene/ozone reactions produce gas- and condensed-phase products and thus contribute to both indoor and outdoor aerosol. These reactions may be important in indoor settings, where terpenes are generated from indoor sources and ambient ozone can reach significant levels. Moreover, airway irritation has been observed in mice exposed to terpene oxidation products (OPs). The aim of this study was to characterize a system for generating and quantifying ultrafine particles formed through terpene/ozone reactions in preparation for inhalation toxicology experiments. Two common monoterpenes, f -pinene and d -limonene, and a hemiterpene, isoprene, were investigated. Ozone and gas-phase terpene were introduced continuously into a reaction flow tube, from which reaction products entered a plexiglass chamber. Particle number, mass, and size distribution (～15-750 nm) were monitored in the chamber for various reactant concentrations and air exchange rates (AERs). In all experiments, ozone was the limiting reagent and the reaction rate was much more rapid than the AER. Particles formed rapidly and in high concentrations in the pinene and limonene systems. Particle formation was slower in the isoprene system and fewer particles were formed; moreover, particle diameters were smaller. In all 3 systems, progressive growth of particles was observed due to condensation and coagulation processes. The isoprene system displayed instability with respect to aerosol characteristics and did not reach steady-state conditions. In the pinene system, ozone concentration was a strong predictor of steady-state particle number and mass concentration and particle diameter. The particle number was greater at higher AERs, but particles were smaller. This study is the first to incorporate measurement of ultrafine particles formed from terpene/ozone reactions into a controlled exposure chamber setting. Following system characterization, we will conduct mouse exposures to further investigate the respiratory effects of gas- and particle-phase terpene OPs.     

Hot-wire ignition of ethanol–oxygen hydrothermal flames

The forced ignition experiments conducted in a novel high pressure hydrothermal spallation drilling pilot plant with a Ni/Cr-60/15 coiled wire are presented here. A water–ethanol mixture is used as fuel and gaseous oxygen as oxidation agent. The ignition characteristics of the combustible mixture are analyzed at 260 bar and for temperatures crossing its pseudo-critical point. The influence of the bulk temperature, the fuel composition and the flow conditions on the forced ignition is shown.     

Corrosion behaviour of boiler steels,coatings and welds in flue gas environments

In recent years there has been a steadily increasing focus on energy efficiency as a means to reduce the negative impact of human activity on climate, and in particular the effect that industrial emissions have on changes in the climate, specifically global warming. As far as power generation is concerned, emissions can be limited by maximizing energy efficiency while ensuring high levels of plant reliability. This paper reports on materials development work involving coated heat exchange alloys and the effect of welding of the coated alloys, simulating fabrication, on subsequent corrosion performance under laboratory conditions. Samples of the common boiler steels P91 (9% Cr) and HCM12A (12% Cr) were treated by chemical vapour deposition (CVD) in a pack cementation process to produce Al‐rich coatings up to 100 µm thick. The samples were machined to give bevelled edges for welding. Welding was carried out using commonly available alloy 625 filler metal. It was found that sound weldments could readily be produced provided that care was taken to limit the heat input during the welding process. Excessive heat input could lead to cracking, but more importantly to dilution of Al in the coating adjacent to the weldment and in segregation of elements (Mo and Nb) in the weldment itself. Both dilution and segregation effects led to decreased corrosion resistance.