Corrosion inhibition of Al–B4C metal matrix composites in a NaCl solution by benzotriazole

Benzotriazole (BTAH) was used for the first time to inhibit the corrosion of Al–B₄C composites in a NaCl solution. Its corrosion inhibition effect was systematically investigated as a function of BTAH concentrations, volume fractions of B₄C particles and immersion time by using potentiodynamic polarization, electrochemical impedance and infrared reflection adsorption spectroscopy techniques. It was found that BTAH is a good corrosion inhibitor for the Al–B₄C MMCs in a 3.5 g L⁻¹ NaCl solution, and its inhibition efficiency increased with increasing BTAH concentration. For the same BTAH concentration and immersion time, higher B₄C volume fraction leads to higher corrosion inhibition efficiency. The inhibition efficiency of benzotriazole was also influenced by the immersion time: the inhibition efficiency increases with the immersion time in the first 18 h. However, prolonging the immersion time leads to a decrease in the inhibition efficiency. As the BTAH was an inhibitor with a cathodic character and it inhibited corrosion by physically adsorbing on B₄C particles at the composite surface, it obeyed the Freundlich adsorption isotherm.     

Chemical nature of superhydrophobic aluminum alloy surfaces produced via a one-step process using fluoroalkyl-silane in a base medium

Various surface characterization techniques were used to study the modified surface chemistry of superhydrophobic aluminum alloy surfaces prepared by immersing the substrates in an aqueous solution containing sodium hydroxide and fluoroalkyl-silane (FAS-17) molecules. The creation of a rough micronanostructure on the treated surfaces was revealed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) and infrared reflection absorption spectroscopy (IRRAS) confirmed the presence of low surface energy functional groups of fluorinated carbon on the superhydrophobic surfaces. IRRAS also revealed the presence of a large number of OH groups on the hydrophilic surfaces. A possible bonding mechanism of the FAS-17 molecules with the aluminum alloy surfaces has been suggested based on the IRRAS and XPS studies. The resulting surfaces demonstrated water contact angles as high as ~166° and contact angle hystereses as low as ~4.5°. A correlation between the contact angle, rms roughnesses, and the chemical nature of the surface has been elucidated.     

Cytochrome c oxidase in rat adrenal and liver: effects of anti-androgen treatment and studies in testicular feminized rats

The role of androgen receptors in androgen-induced changes in rat adrenocortical and liver cytochrome c oxidase (COX) has been investigated. The anti-androgen flutamide, blunted the increase in COX activity and COX subunits II/III and IV, that is seen with androgen treatment. Testicular feminized (Tfm) rats had levels of COX activity and COX subunits II/II and IV in adrenal cortex and liver that were intermediate between the high levels found in normal male rats and the lower levels of normal female rats. These data suggest that androgen effects on adrenal and liver COX are mediated through interactions with androgen receptors known to be present in these issues. However, the observed changes in COX activity and COX subunits were not accompanied by altered levels of mRNAs encoding for COX II or COX IV.     

Secondary structures and starvation-induced frameshifting

The Changes in Sexual Functioning Questionnaire (CSFQ), a structured interview/questionnaire designed to measure illness- and medication-related effects on sexual functioning, is presented with initial evidence of its clinical usefulness in differentiating between those who have sexual dysfunction and those who have no dysfunction. Individuals from clinical and nonclinical samples completed the CSFQ. The sample groups were compared on mean scores on the CSFQ and its subscales. Comparative findings indicate that psychiatric patients diagnosed with a mood disorder have significantly lower sexual functioning when compared with nonpsychiatric outpatients, medical students, and psychiatry residents combined. The CSFQ is a useful measure for assessing medication- or illness-related effects on sexual functioning in a systematic way.     

Chemometric labeling of cereal tissues in multichannel fluorescence microscopy images using discriminant analysis

This paper presents a novel, semiautomatic method for microscopic identification of multicomponent samples, which allows the identification, location, and percentage quantity of each component to be determined. The method involves applying discriminant analysis to a sequence of multichannel fluorescence microscopy images via a supervised learning approach; by selecting groups of pixels that are representative for each component type in a "known" sample, a computer is "taught" how to recognize the behavior (i.e., fluorescence emission) of the various components when illuminated under different spectral conditions. The identity, quantity, and location of these components in "unknown" samples (i.e., samples with the same component types but in different ratios or distributions) can then be investigated. The technique therefore enables semiautomatic quantitative fluorescence microscopy and has potential as a quality control tool. This work demonstrates the application of the technique to artificial and natural samples and critically discusses its quality, potential, and limitations.     

Exploring relationships of spring green-up to moisture and temperature across Wyoming,U.S.A

Vegetation green-up signals the timing of available nutritious plants and shrubs providing high-quality forage for ungulates. In this study, we characterized spatial and temporal patterns of spring phenology and explored how they were related to preceding temperature and moisture conditions. We tested correlations between late winter weather and indicators of the onset and the length of the spring growing period with 250-m resolution time-series satellite data (2001 – 2013) for Wyoming, USA. In western Wyoming mountains, drier and warmer conditions during late winter were associated with earlier spring green-up onset of growth in forests, shrubs, and grasses. In the northeast mountains, onset of spring correlated positively with preceding warmer temperatures, but not with precipitation. In most basin and plains shrublands and grasslands, spring onset was not correlated with temperature, although earlier onset of spring was correlated with drier conditions in 25% of shrub/scrub areas. Results about the length of spring were less definitive, with warmer temperatures related to longer green-up time for 12–30% of the land cover in western mountains but to shorter green-up time periods for 10–20% of the grasses and shrubs in basins and plains. Complex phenological patterns are likely to affect ungulate foraging behaviour on a local scale.     

Rover-Based Autonomous Science by Probabilistic Identification and Evaluation

Autonomous science augments the capabilities of planetary rovers by shifting the identification and selection of science targets from remote operators to the rover itself. This shift frees the rover from wasteful idle time and allows for more selective data collection. This paper presents an approach to autonomous science that is comprised of three components: a Bayesian network that uses image data to identify features; an evaluation algorithm that selects the best features; and, a path-planning algorithm that guides the rover to the most scientifically valuable features. Within this framework, the effectiveness of pairing a larger prime rover with a smaller scout rover to improve autonomous science is investigated. Laboratory-based experiments were used to validate the effectiveness of the Bayesian network for feature identification and the scoring algorithm that has been developed for feature evaluation. Simulations were used to compare the traditional use of a solo prime rover to that of also employing a scout. The results presented here indicate that the inclusion of a scout rover can allow the prime rover to avoid pitfalls or routes with low scientific value.     

On Ultrastructural and Nutritional Aspects of Some Tropical Tuber Starches

Type A starches (Manihot utilissima, Dioscorea dumetorum and Colocasia antiquorum) and type B starches (Canna edulis, Dioscorea alata and Dioscorea cayenensis) are investigated. Results show that the degradation of the pure tuber starch as compared with that of feeds made from a particular starch is more or less the same. However, type A starches are more rapidly degraded by bacterial α-amylase. The susceptibility to attack is compared to the nutritional efficiency of the feeds using axenic and holoxenic chickens. Comparison of the degree of degradation of the starch granules in the crop as well as in the feces (by in vitro and in vivo studies) is made by scanning electron microscopy. Type A starches show always a higher susceptibility to α-amylase attack. The feed efficiency tested on chicken and digestibility of tuber starches in the sheep rumen and in the chicken crop increase as their ease of degradation by bacterial α-amylase (in vitro) increases.