Bond Strength of Direct and Indirect Bonded Brackets After Thermocycling

Thermocycling simulates the temperature dynamics in the oral environment. With direct bonding, thermocycling reduces the bond strength of orthodontic adhesives to tooth structure. The purpose of this study was to evaluate the shear bond strengths (SBS) of one direct and two indirect bonding methods/adhesives after thermocycling. Sixty human premolars were divided into three groups. Teeth in group 1 were bonded directly with Transbond XT. Teeth in group 2 were indirect bonded with Transbond XT/Sondhi Rapid Set, which is chemically cured. Teeth in group 3 were indirect bonded with Enlight LV/Orthosolo and light cured. Each sample was thermocycled between 5°C and 55°C for 500 cycles. Mean SBS in groups 1, 2, and 3 were not statistically significantly different (13.6 ± 2.9, 12.3 ± 3.0, and 11.6 ± 3.2 MPa, respectively; P \u3e .05). However, when these values were compared with the results of a previous study using the same protocol, but without thermocycling, the SBS was reduced significantly (P = .001). Weibull analysis further showed that group 3 had the lowest bonding survival rate at the minimum clinically acceptable bond-strength range. The Adhesive Remnant Index was also determined, and group 2 had a significantly (P \u3c .05) higher percentage of bond failures at the resin/enamel interface

A Comparison of Bond Strength Between Direct- and Indirect-bonding Methods

The purpose of this study was to evaluate and compare the shear bond strength and the sites of bond failure for brackets bonded to teeth, using two indirect-bonding material protocols and a direct-bonding technique. Sixty extracted human premolars were collected and randomly divided into three groups. The direct-bonded group (group 1) used a light-cured adhesive and primer (Transbond XT). One indirect-bonded group (group 2) consisted of a chemical-cured primer (Sondhi Rapid Set) and light-cured adhesive (Transbond XT), whereas the other group (group 3) used a light-cured primer (Orthosolo) and adhesive (Enlight LV). Forty hours after bonding, the samples were debonded. Mean shear bond strengths were 16.27, 13.83, and 14.76 MPa for groups 1, 2, and 3, respectively. A one-way analysis of variance showed no significant difference in mean bond strength between groups (P = .21). Furthermore, a Weibull analysis showed all three groups tested provided over a 90% survival rate at normal masticatory and orthodontic force levels. For each tooth, an Adhesive Remnant Index (ARI) score was determined. Group 2 was found to have a significantly lower ARI score (P \u3c .05) compared with groups 1 and 3. In addition, Pearson correlation coefficients indicated no strong correlation between bond strength and ARI score within or across all groups

Bayesian Spatial Binary Regression for Label Fusion in Structural Neuroimaging

Many analyses of neuroimaging data involve studying one or more regions of interest (ROIs) in a brain image. In order to do so, each ROI must first be identified. Since every brain is unique, the location, size, and shape of each ROI varies across subjects. Thus, each ROI in a brain image must either be manually identified or (semi-) automatically delineated, a task referred to as segmentation. Automatic segmentation often involves mapping a previously manually segmented image to a new brain image and propagating the labels to obtain an estimate of where each ROI is located in the new image. A more recent approach to this problem is to propagate labels from multiple manually segmented atlases and combine the results using a process known as label fusion. To date, most label fusion algorithms either employ voting procedures or impose prior structure and subsequently find the maximum a posteriori estimator (i.e., the posterior mode) through optimization. We propose using a fully Bayesian spatial regression model for label fusion that facilitates direct incorporation of covariate information while making accessible the entire posterior distribution. We discuss the implementation of our model via Markov chain Monte Carlo and illustrate the procedure through both simulation and application to segmentation of the hippocampus, an anatomical structure known to be associated with Alzheimer's disease.Comment: 24 pages, 10 figure

Temperature-dependent regulation of d-cis-[3H]diltiazem binding to Ca2+ channels by 1,4-dihydropyridine channel agonists and antagonists

AbstractThe binding of the Ca2+-channel blocker d-cis-[3H]diltiazem to guinea pig skeletal muscle microsomes is temperature-dependent. At 2°C the KD is 39 nM and Bmax is 11 pmol/mg protein. The binding is fully reversible (K−1 = 0.02 min−1). The binding sites discriminate between the diastereoisomers 1- and d-cis-diltiazem, recognize verapamil, gallopamil and tiapamil, and are sensitive to La3+-inhibition. At 30°C the KD is 37 nM and the Bmax is 2.9 pmol/mg protein. D-cis-diltiazem-labelling is regulated by the 1,4-dihydropyridine Ca2+-channel blockers and a novel Ca2+-channel activator in a temperature-dependent manner. At 30°C an enhancement of d-cis-diltiazem binding by the channel blockers is observed. This is attributed to a Bmax increase. EC50-values for enhancement and the maximal enhancement differ for the individual 1,4-dihydropyridines. At 2°C 1,4-dihydropyridines inhibit d-cis-[3H]diltiazem binding. This is attributed to a Bmax decrease. We have directly labelled one of the drug receptor sites within the Ca2+-channel which can allosterically interact with the 1,4-dihydropyridine binding sites

Small-amplitude normal modes of a vortex in a trapped Bose-Einstein condensate

We consider a cylindrically symmetric trap containing a small Bose-Einstein condensate with a singly quantized vortex on the axis of symmetry. A time-dependent variational Lagrangian analysis yields the small-amplitude dynamics of the vortex and the condensate, directly determining the equations of motion of the coupled normal modes. As found previously from the Bogoliubov equations, there are two rigid dipole modes and one anomalous mode with a negative frequency when seen in the laboratory frame.Comment: 4 pages, no figures, Revte

Social and Economic Stress Related to the HIV/AIDS Epidemic in Botswana

The paper describes the consequences of HIV/AIDS in Botswana; the country with the highest HIV prevalence rate in Africa. In addition to frequently experienced trauma due to sickness and death, many households experience rising health expenditures and a sharp deterioration of incomes. High levels of morbidity and mortality among workers result in depressed returns on investment, reduced productivity and increased expenditure on training and replacement of workers. As the health care system finds it increasingly difficult to cope, home-based care provides an inadequate solution since the home infrastructure of many households is inadequate for proper care of seriously ill patients. The stigma associated with AIDS often isolates fragile households and provides an environment in which abuse of infected individuals and of orphans whose parents have died of AIDS is not uncommon. The quality of education also suffers, resulting in an ill prepared skilled manpower, with adverse consequences for social, economic, and political development as well as for good future governance of the country

HIV/AIDS Care, Coping Strategies and Work Environmental Stress Among Nurses in Botswana

Since 2006 there has been universal acceptance in both developing and industrialized societies that HIV treatment and related services, including more effective programs, be available to all citizens. However, as a result of the worldwide recession and shifting health priorities, progress toward these goals has stalled. While the epidemic continues to grow (approximately 34 million globally, with 2.7 million new cases in 2010), fewer resources are dedicated to treatment and prevention than previously, and clinical staffs, especially nurses are challenged by more patient care responsibilities. This paper focuses on the relationships of HIV/AIDS care, coping strategies and work environmental stress for nurses working in an African country (Botswana) with a significant epidemic. Data for this study was obtained through questionnaires completed by a sample of 201 nurses working in different types of health facilities in rural and urban areas of Botswana. Results show that 65% of the nurses frequently provided care to clients with HIV/AIDS. Only 35% of the nurses provided care to clients with HIV/AIDS infrequently. Those caregivers who often worked with patients infected with HIV reported significantly (p\u3c.05) more role demand , job control and shift work stress and said that their coping strategies were more likely to include taking food supplements. Implications for professional burn out among HIV/AIDS caregivers in developing societies are discussed together with strategies for more effective allocations of health care personnel

HIV/AIDS Care, Coping Strategies and Work Environmental Stress Among Nurses in Botswana

Since 2006 there has been universal acceptance in both developing and industrialized societies that HIV treatment and related services, including more effective programs, be available to all citizens. However, as a result of the worldwide recession and shifting health priorities, progress toward these goals has stalled. While the epidemic continues to grow (approximately 34 million globally, with 2.7 million new cases in 2010), fewer resources are dedicated to treatment and prevention than previously, and clinical staffs, especially nurses are challenged by more patient care responsibilities. This paper focuses on the relationships of HIV/AIDS care, coping strategies and work environmental stress for nurses working in an African country (Botswana) with a significant epidemic. Data for this study was obtained through questionnaires completed by a sample of 201 nurses working in different types of health facilities in rural and urban areas of Botswana. Results show that 65% of the nurses frequently provided care to clients with HIV/AIDS. Only 35% of the nurses provided care to clients with HIV/AIDS infrequently. Those caregivers who often worked with patients infected with HIV reported significantly (