Performance evaluation of TiAlCrYN nanocomposite coatings deposited using four-cathode reactive unbalanced pulsed direct current magnetron sputtering system

Approximately 1.5-2.5 μm thick nanocomposite coatings of TiAlCrYN were deposited using a four-cathode reactive unbalanced pulsed direct current magnetron sputtering system from the sputtering of Ti, Al, Cr, and Y targets in Ar + N₂ plasma. The TiAlCrYN nanocomposite coatings were deposited on various substrates such as high speed steel (HSS) drill bits, mild steel and silicon. TiAlCrYN coatings with almost similar mechanical properties but with different Ti, Al, Cr and Y contents were prepared to study their thermal stability and machining performance. The structural and mechanical properties of the coatings were characterized using X-ray diffraction and nanoindentation technique, respectively. The elemental composition, bonding structure, surface morphology and cross-sectional data were studied using energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy and field-emission scanning electron microscopy, respectively. Nanoscratch tests were performed to determine the adhesive strength of the coatings. The corrosion behavior of TiAlCrYN nanocomposite coatings on mild steel substrate was studied using potentiodynamic polarization in a 3.5% NaCl solution. Micro-Raman spectroscopy was used to characterize the structural changes as a result of heating of the nanocomposite coatings in air (600-1000 °C). TiAlCrYN coatings prepared at 17 at.% Ti, 13 at.% Al, 21 at.% Cr and 1 at.% Y exhibited thermal stability as high as 900 °C in air (denoted as Sample 3). For the performance evaluation, the TiAlCrYN coated HSS drill bits were tested under accelerated machining conditions. With a drill speed of 800 rpm and a feed rate of 0.08 mm/rev the TiAlCrYN coated HSS drill bits (Sample 3) averaged 657 holes, while drilling a 12 mm thick 304 stainless steel plate under dry conditions, before failure. Whereas, the uncoated drill bits failed after drilling 50 holes under the same machining conditions. Results indicated that for the HSS drill bits coated with TiAlCrYN, the tool life increased by a factor of more than 12.     

Induction of labor with use of a Foley catheter and extraamniotic corticosteroids

OBJECTIVE: Our purpose was to examine the hypothesis that corticosteroids, when administered extraamniotically, can enhance the labor process and reduce the induction-to-delivery interval. STUDY DESIGN: A double-blind, randomized study was conducted on 98 women with a gestational age of 36 to 42 weeks, an unfavorable cervix, and medical indications for delivery, who were assigned to receive either 20 mg of dexamethasone in saline solution (study group, n = 50) or saline solution only (control group, n = 48) administered extraamniotically through an intracervical inflated Foley balloon catheter. The net effect of steroids was assessed with use of multivariant logistic regression analysis. RESULTS: The mean time intervals between induction of labor to the active phase and between induction of labor to delivery were significantly shorter in the study group compared with those of the control group (7.8 +/- 3.1 hours vs 9.9 +/- 3.9 hours, p < 0.03, 11.9 +/- 3.0 hours vs 14.5 +/- 4.8 hours, p < 0.01, respectively). Those not receiving steroids were at a 3.2 higher risk of having a longer time interval of induction to delivery (95% confidence interval 1.1 to 9.5). The general success rate in achieving vaginal delivery was, however, similar between the groups. CONCLUSIONS: Induction of labor with use of an intracervical Foley balloon catheter and extraamniotic corticosteroids reduces the time interval from induction of labor to delivery. This may indicate a possible role for corticosteroids in the parturition process.     

Caring for the older patient, Part II: Age-related anatomic and physiologic changes and pathologies

This is the second article of a four-part series on gerontology and its applications to the care of elderly patients in nuclear medicine. This article reviews anatomic and physiologic changes and pathology associated with aging. It also discusses tailoring nuclear medicine procedures according to patients' needs and conditions, as well as adopting changes within the nuclear medicine department to better serve older patients. Upon completion of this article, the reader should be able to: (a) describe normal age-related anatomic and physiologic changes that are observed in older patients; (b) identify common age-related disorders; (c) discuss considerations in tailoring nuclear medicine procedures for older patients; and (d) identify changes in the nuclear medicine facility that would better accommodate older patients.     

Security of capsular fixation: small-versus large-hole plate-hepatic lenses

PURPOSE: To assess the effect of relatively large positioning holes on the security of capsular bag fixation of plate-haptic silicone intraocular lenses (IOLs). SETTING: Center for Research on Ocular Therapeutics and Biodevices, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This study tested the hypothesis that larger holes allow ingrowth of lens material, fibrous tissue, or both through them, which helps fixate the lens more firmly in the capsular bag. Five rabbits had bilateral continuous curvilinear capsulorhexis, phacoemulsification, and implantation of a plate-haptic silicone IOL. An IOL with a small, round positioning hole (Staar AA-4203V) was implanted in the right eye in each rabbit, and a large-hole IOL (Staar AA-4203VF) was implanted in the left eye. After 2 months, all rabbits were killed. The force required to extract one haptic from the capsular bag was measured with a digital force meter. All eyes had histopathological analysis. RESULTS: It was slightly more difficult to extract a large-hole IOL from the capsular bag, although this trend was not statistically significant. However, histopathological analysis consistently showed 360 degree synechia formation through the holes, showing that the IOL could be securely fixed in position. CONCLUSIONS: Proliferation of lens epithelial cells through a large positioning hole in a plate-haptic silicone IOL may improve the long-term security of capsular bag fixation. This will help reduce the incidence of IOL decentration and dislocation.     

National cancer clinical trials: children have equal access; adolescents do not

PURPOSE: To determine whether adolescents with cancer, who in comparison to younger patients have a higher cancer incidence and lower mortality reduction, have equal access to national cancer clinical trials. METHODS: The ethnic/racial distribution of 29,859 subjects < 20 years of age entered onto National Cancer Institute-sponsored clinical trials between January 1, 1991, and June 30, 1994, was compared with the expected distribution of patients of the same age in the United States. RESULTS: The Children's Cancer Group and Pediatric Oncology Group had 29,134 (97.6%) of the total study entries among < 20-year-old subjects during the 3.5 years of surveillance. The adult cooperative groups accounted for < 3% of the clinical trials entries in the 15-19-year age range. When analyzed nationally by region, the under-representation of the older adolescent subjects was universal. From other analyses, the two pediatric cooperative groups were estimated to have registered > 94% of the children < 15 years of age who were expected to have been diagnosed to have cancer, but only 21% of the cancer patients in the 15-19-year age group. CONCLUSIONS: The national pediatric cancer cooperative groups allow the majority of American children < 15 years of age and their families equal opportunity to access clinical cancer trials, regardless of race or ethnicity. Among patients 15-19 years of age, however, > 75% are not being enrolled by any cooperative group sponsored by the National Cancer Institute. Thus, older adolescents are disadvantaged with respect to access to the national clinical trials, regardless of their race or ethnicity.     

Couvelaire uterus

Uteroplacental apoplexy is a rare but nonfatal complication of severe forms of placental abruption. It occurs when vascular damage within the placenta causes hemorrhaging that progresses to and infiltrates the wall of the uterus. It is a syndrome that can only be diagnosed by direct visualization or biopsy (or both). For this reason, its occurrence is perhaps underreported and underestimated in the literature. The subject of this report is a 24-year-old pregnant woman who had a placental abruption an in whom classic uteroplacental apoplexy was diagnosed at the time of her cesarean section.     

Large scale identification of genes involved in cell surface biosynthesis and architecture in Saccharomyces cerevisiae

The sequenced yeast genome offers a unique resource for the analysis of eukaryotic cell function and enables genome-wide screens for genes involved in cellular processes. We have identified genes involved in cell surface assembly by screening transposon-mutagenized cells for altered sensitivity to calcofluor white, followed by supplementary screens to further characterize mutant phenotypes. The mutated genes were directly retrieved from genomic DNA and then matched uniquely to a gene in the yeast genome database. Eighty-two genes with apparent perturbation of the cell surface were identified, with mutations in 65 of them displaying at least one further cell surface phenotype in addition to their modified sensitivity to calcofluor. Fifty of these genes were previously known, 17 encoded proteins whose function could be anticipated through sequence homology or previously recognized phenotypes and 15 genes had no previously known phenotype.