Effect of fluoride on the calcification of allogenic bone implants in rats

Thesis (M.Sc.D.)--Boston University School of Graduate Dentistry, 1974. Periodontics.Bibliography included.In twenty-five (25) male adult rats which had decalcified allogenic bone implants placed in mid-fibular gaps and kept on a low-fluoride casein diet (1 ppm- fluoride), the addition of 25 p.p.m. fluoride to the drinking water did not show any direct detectable relationship to the mg % calcium in the ashed implants or in ashed adjacent tibial bone, nor in the percent ash content. Neither did the fluoride enhance or inhibit the success of the implants. For all implants did calcify and only one control mid-fibular gap closed on its own. It is our conclusion that fluoride at levels used in this experiment have no effect on calcification of allogenic bone implants

Minimum Wages and Poverty

The principal justification for minimum wage legislation resides in improving the economic condition of low-wage workers. Most previous analyses of the distributional effects of minimum wages have been confined to simulation exercises employing rather restrictive assumptions that guarantee the conclusion that an increase in the minimum wage reduces poverty. In contrast, we adopt a more flexible "reduced-form" approach that links increases in both federal and state minima to contemporaneous changes in poverty rates. For the period 1983-96, we find indication of a poverty-reducing effect of minimum wages among older junior-high dropouts and among teenagers. --

User's guide to a system of finite-element supersonic panel flutter programs

The utilization and operation of a set of six computer programs for the prediction of panel flutter at supersonic speeds by finite element methods are described. The programs run individually to determine the flutter behavior of a flat panel where the finite elements which model the panel each have four degrees of freedom (DOF), a curved panel where the finite elements each have four DOF, and a curved panel where the finite elements each have six DOF. The panels are assumed to be of infinite aspect ratio and are subjected to either simply-supported or clamped boundary conditions. The aerodynamics used by these programs are based on piston theory. Application of the program is illustrated by sample cases where the number of beam finite elements equals four, the in-plane tension parameter is 0.0, the maximum camber to panel length ratio for a curved panel case is 0.05, and the Mach number is 2.0. This memorandum provides a user's guide for these programs, describes the parameters that are used, and contains sample output from each of the programs

Beyond Collective Efficacy: New Brief Measures to Assess the Outer Layers of the Social Ecology

Abstract Introduction: Community support can be a valuable interpersonal resource anywhere, yet past research has largely been focused on adults in urban neighborhoods. Because communities are no longer solely defined by a shared physicality, we offer psychometric data on three new measures to assess other communal resources: informal community support, support for community youth, and workplace integration. Methods: Participants (N=1706) from a largely rural, low-income Southern region completed a computer-assisted questionnaire as part of a larger study on character development and personal strength. Ages range from 11 to 70 years old (M=29.3 years; SD=12.3 years); 63% of participants are female. Results: Internal consistency was good for our 3 new measures, .70 to .86 and each scale comprised a single factor in exploratory factor analyses. Correlations with collective efficacy (convergent validity) were all positive and significant and range from .18 to .57. Correlations with measures of subjective well-being range from .21 to .29, and correlations with mental and physical health outcomes ranged from .14 to .23. Implications: Studying communities in addition to individuals and families can potentially shed light on the variety of ways in which community ties can foster well-being and resilience. The three new measures presented here assess important but understudied aspects of communities

Tracking ground state Ba+ ions in an expanding laser–plasma plume using time-resolved vacuum ultraviolet photoionization imaging

We report results from a study of the integrated column density and expansion dynamics of ground-state-selected Ba+ ions in a laser–plasma plume using a new experimental system—VPIF (vacuum-ultraviolet photoabsorption imaging facility). The ions are tracked by recording the attenuation of a pulsed and collimated vacuum ultraviolet beam, tuned to the 5p–6d inner-shell resonance of singly ionized barium, as the expanding plasma plume moves across it. The attenuated beam is allowed to fall on a CCD array where the spatial distribution of the absorption is recorded. Time-resolved ion velocity and integrated column density maps are readily extracted from the photoionization images

EUS-Guided Pancreatic Cyst Ablation: a Clinical and Technical Review

Purpose of Review Pancreatic cystic lesions represent a growing public health dilemma, particularly as our population ages and cross-sectional imaging becomes more sensitive. Mucinous cysts carry a clinically significant risk of developing pancreatic cancer, which carries an extremely poor prognosis. Determining which cysts will develop cancer may be challenging, and surgical resection of the pancreas carries significant morbidity. The goal of this paper is to review the rationale for cyst ablation and discuss prior and current research on cyst ablation techniques and efficacy. Indications, contraindications, and factors related to optimal patient selection are outlined. Recent Findings Endoscopic ultrasound-guided chemoablation of pancreatic cysts has been performed in neoplastic cysts, with varying levels of efficacy. Safety concerns arose due to the risk of pancreatitis in alcohol-based treatments; however, the most recent data using a non-alcohol chemoablation cocktail suggests that ablation is effective without the need for alcohol, resulting in a significantly more favorable adverse event profile. Summary Endoscopic ultrasound-guided chemoablation of neoplastic pancreatic cysts is a promising, minimally invasive approach for treatment of cysts, with recent significant advances in safety and efficacy, suggesting that it should play a role in the treatment algorithm

Determining Pesticide and Nitrate Levels in Spring Water in Northwest Arkansas

Occurrences of pesticides in our nations ground water are on the rise. As states become aware of this problem and begin monitoring programs, incidence of contamination will probably increase. Since the problem of pesticides in groundwater is relatively new, little research has centered on the fate of pesticides after they reach the groundwater environment. In Northwest Arkansas efforts to monitor groundwater for pesticides have been small. Twenty-five springs in Northwest Arkansas were sampled in the fall of 1988, and spring of 1989. Analysis for atrazine, alachlor, metolachlor, diuron, and simazine in spring water was preformed using gas liquid chromatography and high performance liquid chromatography. No detectable residues of any of the selected pesticides were found. Northwest Arkansas is a leader in poultry production. Much of the manure from poultry houses is spread on the sourounding pastures. As this litter decomposes nitrates and phosphates are released. Nitrate and phosphate concentrations were also determined on water from the spring samples. No spring exceeded the EPA\u27s limit of 45 mg/L for nitrate in drinking water. The highest concentration for phosphate in any spring was 1.05 mg/L

The factorial validity and reliability of three versions of the Aggression Questionnaire using Confirmatory Factor Analysis and Exploratory Structural Equation Modelling

The Aggression Questionnaire (AQ) measures aggression in four domains: Anger, Hostility, Physical Aggression and Verbal Aggression. Moreover, a number of shorter versions of the AQ have emerged. The present study used a large sample of adolescents to test three versions of the AQ. In each case we examined a unidimensional model, a hierarchical model, and a four-factor model. Results of Confirmatory Factor Analysis revealed limited support for a unidimensional model in any of the AQ forms, with results supporting the widely used four-factor model, and to a lesser extent, the hierarchical model. Fit indices for both short-forms of the AQ using Exploratory Structural Equation Modelling were very good. However, results also revealed only partial gender invariance for both scales

Food Insecurity Rates Rise Steeply with Recession

Children's HealthWatch finds that the prevalence of food insecurity in a five-city sample of low-income families with young children increased from 18.5 percent to 22.6 percent between 2007 and 2008. This is the largest year-to-year change seen in the dataset since 2001. The increase is an indication of the economic hardships facing low-income families with young children. This data suggests that we are likely to see significant increases in food insecurity when the U.S. Department of Agriculture issues its own statistics for 2008 in late fall