Analysis of diamond-like carbon and Ti/MoS2 coatings on Ti–6Al–4V substrates for applicability to turbine engine applications

Ti–6Al–4V substrates have been coated by diamond-like carbon (DLC) films, with no surface pretreatment, and have been coated by Ti/MoS₂ films, with a simple surface pre-cleaning. The DLC films were deposited by planar coil r.f. inductively-coupled plasma-enhanced chemical vapor deposition (r.f. ICPECVD); the Ti/MoS₂ films were deposited by magnetron sputtering. Both the DLC and Ti/MoS₂ films were characterized by pull tests, hardness tests, scanning electron microscopy (SEM), and wear tests (pin-on-disk and block-on-ring) to compare their adhesion, hardness, surface topology, and wear properties to plasma-sprayed Cu–Ni–In coating currently used for turbine engine applications. The DLC films were easily characterized by their optical properties because they were highly transparent. We used variable-angle spectroscopic ellipsometry (VASE) to characterize thickness and to unequivocally extract real and complex index of refraction, providing a rapid assessment of film quality. Thicker coatings yielded the largest hardness values. The DLC coatings did not require abrasive pretreatment or the formation of bond-layers to ensure good adhesion to the substrate. Simple surface pre-cleaning was also adequate to form well-adhered Ti/MoS₂ on Ti–6Al–4V. The results show that the DLC and Ti/MoS₂ coatings are both much better fretting- and wear-resistant coatings than plasma-sprayed Cu–Ni–In. Both show excellent adhesion to the substrates, less surface roughness, harder surfaces, and more wear resistance than the Cu–Ni–In films.     

Reinterpreting the empathy–altruism relationship: When one into one equals oneness.

Important features of the self-concept can be located outside of the individual and inside close or related others. The authors use this insight to reinterpret data previously said to support the empathy–altruism model of helping, which asserts that empathic concern for another results in selflessness and true altruism. That is, they argue that the conditions that lead to empathic concern also lead to a greater sense of self–other overlap, raising the possibility that helping under these conditions is not selfless but is also directed toward the self. In 3 studies, the impact of empathic concern on willingness to help was eliminated when oneness—a measure of perceived self-other overlap—was considered. Path analyses revealed further that empathic concern increased helping only through its relation to perceived oneness, thereby throwing the empathy–altruism model into question. The authors suggest that empathic concern affects helping primarily as an emotional signal of oneness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Partnering Roles of the IS Executive

IS partnering-the formation of linkages with managers both internal and external to the IS department-is critical to effective leadership in today's strategically focused organizations. This article discusses the leadership and partnering roles essential to IS managers as well as to an ideal IS management team.     

Effect of ethinyl estradiol-dienogest combination on serum androgen concentrations

Antiandrogens or progestins with an antiandrogenic component usually have only a weak antigonadotropic activity. It is thus possible that the antiandrogenic effect on the cellular level is cancelled or at least reduced by an increased ovarian androgen production. The aim of the four submitted clinical studies of the progestin and antiandrogen dienogest alone (0.5-2 mg/day) or of a combined regimen of ethinylestradiol (0.03 mg) plus dienogest (2 mg) (EE/DNG) was to examine the influence on the serum androgen and SHBG concentrations as well as on the serum FSH, LH, progesterone and 17 beta-estradiol concentrations in young women. Like the progesterone derivatives, dienogest has a relatively low antigonadotropic activity. Inhibition of ovulation is mainly produced by peripheral mechanisms such as the reduction of preovulatory 17 beta-estradiol secretion. Dienogest alone has no significant effects on the serum SHBG and androgen concentrations. Unlike this, the combination of EE plus DNG markedly increases SHBG concentrations (to 2.1-3.7 fold the basal levels). The decrease in serum androgens with total testosterone (by 17 and 40%), free testosterone (by 48 and 54%) and dehydroepiandrosterone sulfate (by 51%) corresponds to the values shown in the literature for other oral contraceptives with modern progestins. EE/DNG does not affect the serum concentrations of 5 alpha-dihydrotestosterone (DHT), although the marker of the peripheral transformation from T to DHT, androstanediol glucuronide, is distinctly reduced (by 38%). In a double-blind comparison no differences are found between EE/DNG and a regimen combining 0.02 mg of ethinylestradiol and 0.150 mg of desogestrel. Solely the SHBG concentrations, with EE/DNG, as expected, are significantly higher. In a sequential regimen, dienogest, chlormadinone acetate and desogestrel (progestins without binding to SHBG) enhance the inhibitory effect of ethinylestradiol sulfonate on free testosterone, whereas norethindrone acetate and levonorgestrel (progestins with a strong binding to SHBG) reduce this effect of the estrogen significantly. These results exclude the possibility that the very distinct antiandrogenic effect of dienogest on a cellular level is neutralised or reduced by an increased systemic supply of androgen.     

Human telomerase inhibition by regioisomeric disubstituted amidoanthracene-9,10-diones

Telomerase is an attractive target for the design of new anticancer drugs. We have previously described a series of 1,4- and 2, 6-difunctionalized amidoanthracene-9,10-diones that inhibit human telomerase via stabilization of telomeric G-quadruplex structures. The present study details the preparation of three further, distinct series of regioisomeric difunctionalized amidoanthracene-9,10-diones substituted at the 1,5-, 1,8-, and 2,7-positions, respectively. Their in vitro cytotoxicity and Taq DNA polymerase and human telomerase inhibition properties are reported and compared with those of their 1,4- and 2,6-isomers. Potent telomerase inhibition (telIC50 values 1.3-17.3 microM) is exhibited within each isomeric series. In addition, biophysical and molecular modeling studies have been conducted to examine binding to the target G-quadruplex structure formed by the folding of telomeric DNA. These studies indicate that the isomeric diamidoanthracene-9,10-diones bind to the human telomeric G-quadruplex structure with a stoichiometry of 1:1. Plausible G-quadruplex-ligand complexes have been identified for each isomeric family, with three distinct modes of intercalative binding being proposed. The exact mode of intercalative binding is dictated by the positional placement of substituent side chains. Furthermore, in contrast to previous studies directed toward triplex DNA, it is evident that stringent control over positional attachment of substituents is not a necessity for effective telomerase inhibition.     

Mild head injury in children and adolescents: A review of studies (1970–1995).

In this article, the authors provide a comprehensive review of the research of mild head injury in children and adolescents from 1970 to 1995. Because of marked variability in methodologies across studies, a preliminary box-score tally was computed, without regard to studies' scientific or methodological merit. These results revealed 13 adverse, 18 null, and 9 indeterminate findings related to neuropsychological, academic, or psychosocial outcome. When studies were classified based on methodological merit, the stronger studies were generally associated with null outcomes across domains. However, a few of the less stronger neuropsychological studies (5 of 40) reported subthreshold and transitory alterations during the early postinjury period. At the present time, cautious acceptance of the null hypothesis is recommended until more definitive studies are conducted that address the problems raised in this review. (PsycINFO Database Record (c) 2010 APA, all rights reserved)