Conduct Research on Gas Chromatographic Systems to Analyze Certain Chemical Constituents of the Surface of the Moon Progress Report, 1 Jul. - 31 Dec. 1965

Fast scan high resolution mass spectrometer system for use with gas chromatography instrumentatio

The Composition of Strike Activity in the Construction Industry

This study shows that strikes in construction have, by most measures, increased during the years since 1949, a period during which strike activity tended to decline in American industry as a whole. The authors demonstrate that this increase has resulted not from an increase in the number of wage disputes but from a growing number of jurisdictional strikes and the increasing severity of economic and union-organizing strikes. They also show that the number of strikes in construction does not vary significantly with the unemployment rate in that industry nor with the presence of wage controls, but both of those factors have a significant impact on the composition of strike activity in construction

Vitamin D in the Prevention and Treatment of Oral Cancer: A Scoping Review

Introduction: Oral cancer is a serious health problem with an increasing incidence worldwide. Researchers have studied the potential anti-cancerous action of vitamin D and its association with several cancers including oral cancer. The purpose of this scoping review is to synthesize the existing literature on the role of vitamin D on oral cancer. Methods: A scoping review of the literature was conducted using the framework developed by Arkey and O’Malley and the PRISMA-ScR guidelines. Nine databases were searched for peer-reviewed human studies published in English that either investigated the association of vitamin D with, or its impact on either the prevention or treatment of oral cancer. The authors then extracted data using a predefined form to summarize information about article type, study design, participant characteristics, interventions, and outcomes. Results: Fifteen articles met the review criteria. Among the 15 studies, 11 were case–control, 3 were cohort studies, and 1 was a clinical trial. In four studies, the evidence supported a preventive action of vitamin D against oral cancer and a reduction in the negative side effects associated with chemo- and radiotherapy. Several studies that focused on genetic polymorphisms and the expression of the 1,25 dihydroxyvitamin D3 receptor (VDR) suggested significant associations with vitamin D and increased oral cancer risk and worse survival rates. In contrast, two studies did not reveal a strong association between vitamin D and oral cancer. Conclusions: The current evidence suggests an association between vitamin D deficiency and an increased risk of oral cancer. VDR gene polymorphisms might also be a part of future preventive and therapeutic strategies against oral cancer. Carefully designed studies are required to explore and define what role, if any, vitamin D might play in the prevention and treatment of oral cancer

Association between Fluoride Exposure and Blood pressure

Objectives: This study investigated whether fluoride was associated with an increased prevalence of high blood pressure (BP) among adolescents in the United States. Methods: The study sample consisted of 2015–2016 National Health and Nutrition Examination Survey participants aged 13–17 years. Independent-samples t-tests, Chi-square tests, and regression models were used to analyze the data. Results: A total of 814 participants met the study criteria. The findings showed that the proportion of patients with high levels of water or plasma fluoride in the high BP group was higher than that in the normal BP group. However, after adjusting for sociodemographic covariates, neither water nor plasma fluoride levels were significantly associated with a high BP. Conclusions: This study did not find an association between either water or plasma fluoride levels and high BP. Further study is needed to exclude a dose dependent effect at higher levels of fluoride

Specific in vivo deletion of B-cell subpopulations expressing human immunoglobulins by the B-cell superantigen protein L

Some pathogens have evolved to produce proteins, called B-cell superantigens, that can interact with human immunoglobulin variable regions, independently of the combining site, and activate B lymphocytes that express the target immunoglobulins. However, the in vivo consequences of these interactions on human B-cell numbers and function are largely unknown. Using transgenic mice expressing fully human immunoglobulins, we studied the consequences of in vivo exposure of protein L of Peptostreptococcus magnus with human immunoglobulins. In the mature pool of B cells, protein L exposure resulted in a specific reduction of splenic marginal-zone B cells and peritoneal B-1 cells. Splenic B cells exhibited a skewed light-chain repertoire consistent with the capacity of protein L to bind specific kappa gene products. Remarkably, these two B-cell subsets are implicated in innate B-cell immunity, allowing rapid clearance of pathogens. Thus, the present study reveals a novel mechanism that may be used by some infectious agents to subvert a first line of the host's immune defense

Variation in antibiotic treatment for diabetic patients with serious foot infections: A retrospective observational study

<p>Abstract</p> <p>Background</p> <p>Diabetic foot infections are common, serious, and diverse. There is uncertainty about optimal antibiotic treatment, and probably substantial variation in practice. Our aim was to document whether this is the case: A finding that would raise questions about the comparative cost-effectiveness of different regimens and also open the possibility of examining costs and outcomes to determine which should be preferred.</p> <p>Methods</p> <p>We used the Veterans Health Administration (VA) Diabetes Epidemiology Cohorts (DEpiC) database to conduct a retrospective observational study of hospitalized patients with diabetic foot infections. DEpiC contains computerized VA and Medicare patient-level data for VA patients with diabetes since 1998, including demographics, ICD-9-CM diagnostic codes, antibiotics prescribed, and VA facility. We identified all patients with ICD-9-CM codes for cellulitis/abscess of the foot and then sub-grouped them according to whether they had cellulitis/abscess plus codes for gangrene, osteomyelitis, skin ulcer, or none of these. For each facility, we determined: 1) The proportion of patients treated with an antibiotic and the initial route of administration; 2) The first antibiotic regimen prescribed for each patient, defined as treatment with the same antibiotic, or combination of antibiotics, for at least 5 continuous days; and 3) The antibacterial spectrum of the first regimen.</p> <p>Results</p> <p>We identified 3,792 patients with cellulitis/abscess of the foot either alone (16.4%), or with ulcer (32.6%), osteomyelitis (19.0%) or gangrene (32.0%). Antibiotics were prescribed for 98.9%. At least 5 continuous days of treatment with an unchanged regimen of one or more antibiotics was prescribed for 59.3%. The means and (ranges) across facilities of the three most common regimens were: 16.4%, (22.8%); 15.7%, (36.1%); and 10.8%, (50.5%). The range of variation across facilities proved substantially greater than that across the different categories of foot infection. We found similar variation in the spectrum of the antibiotic regimen.</p> <p>Conclusions</p> <p>The large variations in regimen appear to reflect differences in facility practice styles rather than case mix. It is unlikely that all regimens are equally cost-effective. Our methods make possible evaluation of many regimens across many facilities, and can be applied in further studies to determine which antibiotic regimens should be preferred.</p

A National Study Exploring the Association Between Fluoride Levels and Dental Fluorosis

Importance: While the effects of fluoride on health have been widely researched, fewer high-quality studies examine the association of fluoride levels in water and dental fluorosis. Objective: To investigate the association between fluoride exposure from drinking water and dental fluorosis. Design, setting, and participants: This cross-sectional study used the 2013-2014 and 2015-2016 National Health and Nutrition Examination Survey (NHANES) data (January 1, 2013, through December 31, 2016). NHANES uses a complex sampling technique to develop nationally representative sample estimates of the US population that consists of interviews and physical assessments. Children and adolescents aged 6 to 15 years were included because NHANES contains their data for all 3 forms of fluoride measures: plasma fluoride levels, water levels of fluoride, and dietary fluoride supplementation. Data were analyzed from January 1 to April 30, 2023. Exposures: Water and plasma fluoride levels were measured by laboratory personnel. Dietary fluoride supplement data were self-reported. Main outcomes and measures: The Dean's Fluorosis Index was used to evaluate fluorosis status for each tooth. The dental fluorosis severity value was based on the second most affected tooth. Independent variables included plasma and water fluoride concentrations and dietary fluoride supplementation. An independent samples t test was used to compare fluoride exposures between groups, and Pearson correlation assessed the association between plasma and water fluoride levels. To assess whether fluoride exposures were associated with dental fluorosis, logistic regression analyses were conducted. Results: There were 1543 participants in the 2013-2014 NHANES cycle (weighted proportion male, 51.9%; mean [SD] age, 11.0 [2.7] years) and 1452 in the 2015-2016 cycle (weighted proportion male, 52.6%; mean [SD] age, 11.1 [2.8] years). A weighted 87.3% exhibited some degree of fluorosis in the 2013-2014 cycle and 68.2% in the 2015-2016 cycle. Higher fluoride levels in water and plasma were significantly associated with higher odds of dental fluorosis (adjusted odds ratios, 2.378 [95% CI, 2.372-2.383] in the 2013-2014 cycle and 1.568 [95% CI, 1.564-1.571] in the 2015-2016 cycle). Conclusions and relevance: The findings of this cross-sectional study suggest that exposure to higher concentrations of fluoride in water and having higher plasma levels of fluoride were associated with a greater risk of dental fluorosis. Further research can help policy makers develop policies that balance substantial caries prevention with the risk of dental fluorosis.</p

Practice-Focused, Constructivist Grounded Theory Methodology In Higher Education Leadership Research

A growing body of education research considers practices, however there is less focus on a methodology that enables practical analysis of practices. Use of practice theory is growing, particularly in work and organisational studies, but practice focused studies more frequently address theoretical than methodological agenda. This chapter proposes a practice-focused, constructivist grounded theory methodology as one approach which can address this gap. After first considering the ways in which, separately and in combination, practice-theory and constructivist grounded theory can support higher education leadership and management research, the chapter considers implementation of this methodology by drawing on a study into the practice of authority in higher education leadership. It concludes by considering some implications for the ways in which practices can be understood and the affordances and limitations of this methodology.Peer reviewe