Effects of varying oxygen partial pressure on molten silicon-ceramic substrate interactions

The silicon sessile drop contact angle was measured on hot pressed silicon nitride, silicon nitride coated on hot pressed silicon nitride, silicon carbon coated on graphite, and on Sialon to determine the degree to which silicon wets these substances. The post-sessile drop experiment samples were sectioned and photomicrographs were taken of the silicon-substrate interface to observe the degree of surface dissolution and degradation. Of these materials, silicon did not form a true sessile drop on the SiC on graphite due to infiltration of the silicon through the SiC coating, nor on the Sialon due to the formation of a more-or-less rigid coating on the liquid silicon. The most wetting was obtained on the coated Si3N4 with a value of 42 deg. The oxygen concentrations in a silicon ribbon furnace and in a sessile drop furnace were measured using the protable thoria-yttria solid solution electrolyte oxygen sensor. Oxygen partial pressures of 10 to the minus 7 power atm and 10 to the minus 8 power atm were obtained at the two facilities. These measurements are believed to represent nonequilibrium conditions

Study program to develop and evaluate die and container materials for the growth of silicon ribbons

The development and evaluation of proprietary coatings of pure silicon carbide, silicon nitride, and aluminum nitride on less pure hot pressed substrates of the respective ceramic materials, is described. Silicon sessile drop experiments were performed on coated test specimens under controlled oxygen partial pressure. Prior to testing, X-ray diffraction and SEM characterization was performed. The reaction interfaces were characterized after testing with optical and scanning electron microscopy and Auger electron spectroscopy. Increasing the oxygen partial pressure was found to increase the molten silicon contact angle, apparently because adsorbed oxygen lowers the solid-vapor interfacial free energy. It was also found that adsorbed oxygen increased the degree of attack of molten silicon upon the chemical vapor deposited coatings. Cost projections show that reasonably priced, coated, molten silicon resistant refractory material shapes are obtainable

Cognitive abilities that predict success in a computer-based training program.

PURPOSE: The purposes of this study were (a) to identify cognitive abilities and other factors related to successful completion of training for computer-based tasks that simulated real jobs and (b) to create a brief assessment battery useful in assessing older adults for these kinds of jobs. DESIGN AND METHODS: Participants from three age groups (young, middle-aged, and older) completed a battery of cognitive measures. They then trained on one of three computer-based tasks that simulated actual jobs and were asked to perform the tasks for 3 days. We recorded whether they completed training and whether and how well they did the tasks. In a series of logistic regressions, we evaluated the ability of a subset of cognitive measures drawn from a larger battery to predict participants\u27 ability to successfully complete training and go on to task performance. RESULTS: Results confirmed theory-based expectations that measures of domain knowledge, crystallized intelligence, memory, and psychomotor speed would predict success in computer-based activities. A brief battery was able to predict older adults\u27 successful completion of training for one task but was less useful for another. IMPLICATIONS: A brief battery of cognitive measures may be useful in evaluating individuals for job selection. Different measures are related to job-related criteria depending on task and group evaluated, although it was not possible to identify a reduced battery for one task. The specific cognitive abilities related to participants\u27 success have implications for task and interface design for the elderly population

Increased risk of asthma at age 10 years for children sensitized to multiple allergens

BACKGROUND: Childhood sensitization patterns have been previously found to be related to variable risk of early life allergic disease in several birth cohorts. OBJECTIVE: To determine whether these risks persist into later childhood. METHODS: In the birth cohort of the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study, previous latent class analysis based on sensitization to 10 allergens found the following 4 early life sensitization patterns at age 2 years: highly sensitized, milk/egg dominated, peanut and inhalant(s), and low to no sensitization. At an age 10 study-specific visit, children were evaluated by an allergist for current asthma and atopic dermatitis through a physical examination and interviews with the child and parent or guardian. Total and specific immunoglobulin E (IgE), spirometry, and methacholine challenge were also completed. RESULTS: Compared with children sensitized to none or 1 allergen, children sensitized to 4 or more food and inhalant allergens at age 2 had the highest risk of current asthma (relative risk [RR], 4.42; 95% confidence interval [CI], 2.58-7.59; P \u3c .001) and bronchial hyperresponsiveness (RR, 1.77; 95% CI, 1.29-2.42; P \u3c .001). In addition, they had the highest levels of total IgE (geometric mean, 800 IU/mL; 95% CI, 416-1536) among the 4 groups. Risk of current atopic dermatitis did not depend on pattern of sensitization but remained increased for children with any sensitization (RR, 2.23; 95% CI, 1.40-3.55; P \u3c .001). No differences in spirometry (forced expiratory volume in 1 second, forced expiratory flow between 25% and 75%, and forced expiratory volume in 1 second/forced vital capacity) were identified. CONCLUSION: The previously reported importance of a specific pattern of sensitization in early life (sensitization to ≥4 inhalant and food allergens) continues to be associated with an increased risk of asthma, bronchial hyperresponsiveness, and high total IgE at age 10 years

Tumor necrosis factor-alpha levels in HIV-1 seropositive injecting drug users.

TNF-alpha is a highly pleiotropic cytokine and plays an important role in regulating HIV-1 replication. It may compromise the integrity of the blood-brain-barrier and, thus, may contribute to the neurotoxicity of HIV-1-infection. Both intravenous drug abuse (IDU) and HIV infection can increase TNF-alpha activity, but little information is available on the effects of a combination of these factors on TNF-alpha. We investigated plasma TNF-alpha levels and mRNA in the peripheral monocytes of 166 men and women in three groups: HIV-1-positive IDUs, HIV-1-negative IDUs, and HIV-negative non-IDU control participants. HIV-1-positive IDUs had higher TNF-alpha levels than HIV-1-negative IDUs who, in turn, had higher levels than controls. TNF-alpha mRNA expression in peripheral monocytes was significantly increased in both HIV-1-positive and negative IDUs compared to controls. These findings show that the effects of HIV infection and intravenous drug use may be additive in increasing TNF-alpha levels. Given the multiple effects of TNF-alpha in HIV infection, additional investigation of its role is needed

Infant Feeding Practices and Subsequent Dietary Patterns of School-Aged Children in a US Birth Cohort

BACKGROUND: Infant feeding practices are thought to shape food acceptance and preferences. However, few studies have evaluated whether these affect child diet later in life. OBJECTIVE: The study objective was to examine the association between infant feeding practices and dietary patterns (DPs) in school-aged children. DESIGN: A secondary analysis of data from a diverse prospective birth cohort with 10 years of follow-up (WHEALS [Wayne County Health Environment Allergy and Asthma Longitudinal Study]) was conducted. PARTICIPANTS/SETTING: Children from the WHEALS (Detroit, MI, born 2003 through 2007) who completed a food screener at age 10 years were included (471 of 1,258 original participants). MAIN OUTCOME MEASURES: The main outcome was DPs at age 10 years, identified using the Block Kids Food Screener. STATISTICAL ANALYSIS PERFORMED: Latent class analysis was applied for DP identification. Breastfeeding and age at solid food introduction were associated with DPs using a 3-step approach for latent class modeling based on multinomial logistic regression models. RESULTS: The following childhood DPs were identified: processed/energy-dense food (35%), variety plus high intake (41%), and healthy (24%). After weighting for loss to follow-up and covariate adjustment, compared with formula-fed children at 1 month, breastfed children had 0.41 times lower odds of the processed/energy-dense food DP vs the healthy DP (95% CI 0.14 to 1.25) and 0.53 times lower odds of the variety plus high intake DP (95% CI 0.17 to 1.61), neither of which were statistically significant. Results were similar, but more imprecise, for breastfeeding at 6 months. In addition, the association between age at solid food introduction and DP was nonsignificant, with each 1-month increase in age at solid food introduction associated with 0.81 times lower odds of the processed/energy-dense food DP relative to the healthy DP (95% CI 0.64 to 1.02). CONCLUSIONS: A significant association between early life feeding practices and dietary patterns at school age was not detected. Large studies with follow-up beyond early childhood that can also adjust for the multitude of potential confounders associated with breastfeeding are needed

Evidence for geomagnetic excursions recorded in Brunhes and Matuyama Chron lavas from the trans‐Mexican volcanic belt

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99072/1/arar_methodology.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99072/2/jgrb50214.pd

Hodgkin's lymphoma presenting with markedly elevated IgE: a case report

<p>Abstract</p> <p>Background</p> <p>Markedly elevated IgE as a manifestation of a lymphoproliferative disorder has been only rarely reported.</p> <p>Case Presentation</p> <p>We present the case of a 22 year old female referred to the adult Allergy & Clinical Immunology clinic for an extremely elevated IgE level, eventually diagnosed with Hodgkin's lymphoma. She had no history of atopy, recurrent infections, eczema or periodontal disease; stool was negative for ova & parasites. Chest X-ray revealed large bilateral anterior mediastinal masses that demonstrated prominent uptake on gallium scan. Mediastinal lymph node biopsy was consistent with Hodgkin's lymphoma, nodular sclerosing subtype, grade I/II.</p> <p>Conclusion</p> <p>Although uncommon, markedly elevated IgE may be a manifestation of a malignant process, most notably both Hodgkin's and Non-Hodgkin's lymphomas. This diagnosis should be considered in evaluating an otherwise unexplained elevation of IgE.</p

Pulmonary function testing in HTLV-I and HTLV-II infected humans: a cohort study

BACKGROUND: HTLV-I infection has been linked to lung pathology and HTLV-II has been associated with an increased incidence of pneumonia and acute bronchitis. However it is unknown whether HTLV-I or -II infection alters pulmonary function. METHODS: We performed pulmonary function testing on HTLV-I, HTLV-II and HTLV seronegative subjects from the HTLV outcomes study (HOST), including vital capacity (VC), forced expiratory volume in one second (FEV(1)), and diffusing lung capacity for carbon monoxide (DLCO) corrected for hemoglobin and lung volume. Multivariable analysis adjusted for differences in age, gender, race/ethnicity, height and smoking history. RESULTS: Mean (standard deviation) pulmonary function values among the 257 subjects were as follows: FVC = 3.74 (0.89) L, FEV(1 )= 2.93 (0.67) L, DLCO(corr )= 23.82 (5.89) ml/min/mmHg, alveolar ventilation (VA) = 5.25 (1.20) L and DLCO(corr)/VA = 4.54 (0.87) ml/min/mmHg/L. There were no differences in FVC, FEV1 and DLCO(corr)/VA by HTLV status. For DLCO(corr), HTLV-I and HTLV-II subjects had slightly lower values than seronegatives, but neither difference was statistically significant after adjustment for confounding. CONCLUSIONS: There was no difference in measured pulmonary function and diffusing capacity in generally healthy HTLV-I and HTLV-II subjects compared to seronegatives. These results suggest that previously described HTLV-associated abnormalities in bronchoalveolar cells and fluid may not affect pulmonary function