3,457 research outputs found
Restorative Dentistry: Dental composite depth of cure with halogen and blue light emitting diode technology
Objectives To test the hypothesis that a blue light emitting diode (LED) light curing unit (LCU) can produce an equal dental composite depth of cure to a halogen LCU adjusted to give an irradiance of 300 mWcm–2 and to characterise the LCU's light outputs. Materials and methods Depth of cure for three popular composites was determined using a penetrometer. The Student's t test was used to analyse the depth of cure results. A power meter and a spectrometer measured the light output. Results The spectral distribution of the LCUs differed strongly. The irradiance for the LED and halogen LCUs were 290 mWcm–2 and 455 mWcm–2, when calculated from the scientific power meter measurements. The LED LCU cured all three dental composites to a significantly greater (P < 0.05) depth than the halogen LCU. Conclusions An LED LCU with an irradiance 64% of a halogen LCU achieved a significantly greater depth of cure. The LCU's spectral distribution of emitted light should be considered in addition to irradiance as a performance indicator. LED LCUs may have a potential for use in dental practice because their performance does not significantly reduce with time as do conventional halogen LCUs
Relationship of Eccentric Strength and Forward Perturbation Restabilization After Foot Contact
Background: Forward falls are the most common fall direction and pose safety concerns for adults. To prevent forward falls, compensatory steps, and change-in-support reactions (e.g., foot contact) are critical for restabilizing center of mass after unpredictable, balance disturbances. Multi-joint, lower limb eccentric and isometric strength may provide additional insight on foot contact responses after a forward, temporally unpredictable perturbation. Multi-joint, eccentric muscular contractions have been found to result in significant neuromuscular adaptations (e.g., hypertrophy and muscular strength) and have higher retention capabilities than concentric contractions. Due to the importance of muscular strength in balance recovery, eccentric muscular strength could provide a new insight into improving future fall prevention programs. The primary aim of our investigation was to determine the relationship between restabilization after foot contact, age, and self-reported physical activity in response to a forward, temporally unpredictable perturbation and multi-joint muscular strength in the lower limbs. We hypothesized that adults who were faster at restabilizing after foot contact (e.g., time to restabilize), would produce greater multi-joint eccentric and/or isometric peak force. Our secondary aim was to assess the mean difference between preferred and non-preferred limb time to restabilize. We hypothesized that adults would restabilize faster on their preferred limb compared to non-preferred limb.
Research Question: Are adults with a greater capacity to restabilize after foot contact (time to restabilize) able to produce greater multi-joint eccentric and/or isometric peak force?
Our central hypothesis was that adults who have a greater capacity to restabilize after foot contact, or time to restabilize, would produce greater multi-joint eccentric and/or isometric peak force. Do adults restabilize faster on their preferred limb compared to their non-preferred? Our secondary hypothesis was that adults would restabilize faster on their preferred limb compared to non-preferred limb.
Methods: Our sample consisted of 30 adults (31.2 ± 12.1 years, range: 18-58). Participants performed two blocks of 12 trials of forward, temporally unpredictable perturbation trials on both their preferred and non-preferred stepping limbs followed by assessments of multi-joint eccentric and isometric strength. Multivariate, linear regressions were used to evaluate the relationships and trends among variables. A paired-samples t-test was conducted to assess the mean differences between preferred and non-preferred limb time to restabilize.
Results: Individual multiple linear regression analyses indicated that neither multi-joint eccentric (r = 0.385, p = 0.308) nor isometric (r = 0.317, p = 0.519) strength had a significant impact on restabilization time in response to a forward perturbation in our sample of adults. A paired-sample t-test indicated no mean difference between preferred limb and non-preferred limb time to restabilize (t (28) = 0.980, p = 0.335).
Significance: Eccentric and isometric multi-joint lower body strength was not a performance predictor for restabilization time to a forward perturbation. Additionally, restabilization time did not differ between limbs. Future work will investigate the impact of lower limb multi-joint eccentric rate of force development as well as surface electromyography to assess whether these measures provide additional insight on forward step restabilization
Brca2 and Trp53 deficiency cooperate in the progression of mouse prostate tumourigenesis.
Epidemiological studies have shown that one of the strongest risk factors for prostate cancer is a family history of the disease, suggesting that inherited factors play a major role in prostate cancer susceptibility. Germline mutations in BRCA2 predispose to breast and ovarian cancer with its predominant tumour suppressor function thought to be the repair of DNA double-strand breaks. BRCA2 has also been implicated in prostate cancer etiology, but it is unclear the impact that mutations in this gene have on prostate tumourigenesis. Here we have undertaken a genetic analysis in the mouse to determine the role of Brca2 in the adult prostate. We show that deletion of Brca2 specifically in prostate epithelia results in focal hyperplasia and low-grade prostate intraepithelial neoplasia (PIN) in animals over 12 months of age. Simultaneous deletion of Brca2 and the tumour suppressor Trp53 in prostate epithelia gave rise to focal hyperplasia and atypical cells at 6 months, leading to high-grade PIN in animals from 12 months. Epithelial cells in these lesions show an increase in DNA damage and have higher levels of proliferation, but also elevated apoptosis. Castration of Brca2;Trp53 mutant animals led to regression of PIN lesions, but atypical cells persisted that continued to proliferate and express nuclear androgen receptor. This study provides evidence that Brca2 can act as a tumour suppressor in the prostate, and the model we describe should prove useful in the development of new therapeutic approaches
Integration of FM and asset management expertise in digital 3D building models
Purpose: The research establishes a Conceptual Process Model (CPM) as shown in Figure 1 which shows how Facility Management (FM) and Asset Management (AM) know-how, 3D laser scanning and Building Information Modelling (BIM) can be combined with virtual design and simulation techniques to help managers make better decisions about feasibility report options and to add value and optimize existing buildings performance and quality.
Design methodology and approach: Mixed methods were used including a review of BIMÂ literature and industry best practice. Seven semi-structured interviews were held with stakeholders from different stages in the BIM process. The initial CPM was subsequently refined during the research project based on feedback from the interviews. The 3D laser scanning element of the CPM was tested using two ZHAW university buildings and the findings triangulated with a feedback mechanism to further improve the model.
Originality and findings: The findings helped to develop a model which can be used by key stakeholders as a guide when considering the integration of FM and AM know-how, with 3D scanning in the creation of a BIM model for existing buildings, which constitute approximately 98% of the building stock. The focus is on combining existing know-how with the BIM process and simulation techniques to identify, simulate and evaluate the best building improvement options for feasibility reports prior to a decision to proceed. The CPM meets the need to develop a workflow with a focus on digitalisation of the existing built environment and creation of appropriate BIM model(s). The models can then be used for simulation purposes looking at cost benefit optimisation, energy efficiency, life cycle costing (LCC) etc. as well as creating virtual walk through models that can be viewed by end users, Facility Managers (FMs) and Asset Managers (AMs) to improve workplace environments and FM and AM operation
The evaluation of Education Maintenance Allowance Pilots: three years' evidence: a quantitative evaluation
This is the third report of the longitudinal quantitative evaluation of Education Maintenance Allowance (EMA) pilots and the first since the government announced that EMA is to be rolled out nationally from 2004. The evaluation was commissioned in 1999, by the Department for Education and Skills (DfES) from a consortium of research organisations, led by the Centre for Research in Social Policy (CRSP) and including the National Centre for Social Research, the Institute for Fiscal Studies (IFS) and the National Institute for Careers Education and Counselling (NICEC).
The statistical evaluation design is a longitudinal cohort study involving large random sample surveys of young people (and their parents) in 10 EMA pilot areas and eleven control areas. Two cohorts of young people were selected from Child Benefit records. The first cohort of young people left compulsory schooling in the summer of 1999 and they, and their parents, were interviewed between October 1999 and April 2000 (Year 12 interview). A second interview was carried out with these young people between October 2000 and April 2001 (Year 13 interview). The second cohort left compulsory education the following summer of 2000 and young people, and their parents, were first interviewed between October 2000 and April 2001.
The report uses both propensity score matching (PSM) and descriptive techniques, each of which brings their own particular strengths to the analysis
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Resonance Raman and optical dephasing study of HITCI
Line shape analysis based on resonance Raman spectra of HITCI is used to determine the details of the vibrational part of the line broadening function. Forced Light Scattering with 20 fs pulses from a Ti: sapphire laser measured optical dephasing probing with an Ar+ laser. The observed response is well described by the line broadening function derived from the fluorescence line shape
Flight test evaluation of an RAF high altitude partial pressure protective assembly
A partial pressure suit was evaluated during tests in an F-104 and F-15 as a protective garment for emergency descents. The garment is an pressure jerkin and modified anti-g suit combined with an oronasal mask. The garment can be donned and doffed at the aircraft to minimize thermal buildup. The oronasal mask was favored by the pilots due to its immobility on the face during high g-loading. The garment was chosen to provide optimum dexterity for the pilot, which is not available in a full pressure suit, while protecting the pilot at altitudes up to 18,288 meters, during a cabin decompression, and subsequent aircraft descent. During cabin decompressions in the F-104 and F-15, cabin pressure altitude was measured at various aircraft angles of attack, Mach numbers, and altitudes to determine the effect of the aerodynamic slipstream on the cabin altitude
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Reducing weight and increasing physical activity in people at high risk of cardiovascular disease: a randomised controlled trial comparing the effectiveness of enhanced motivational interviewing intervention with usual care.
OBJECTIVE: The epidemic of obesity is contributing to the increasing prevalence of people at high risk of cardiovascular disease (CVD), negating the medical advances in reducing CVD mortality. We compared the clinical and cost-effectiveness of an intensive lifestyle intervention consisting of enhanced motivational interviewing in reducing weight and increasing physical activity for patients at high risk of CVD. METHODS: A three-arm, single-blind, parallel-group randomised controlled trial was conducted in consenting primary care centres in south London. We recruited patients aged 40-74 years with a QRisk2 score ≥20.0%, which indicates the probability of having a CVD event in the next 10 years. The intervention was enhanced motivational interviewing which included additional behaviour change techniques and was delivered by health trainers in 10 sessions over 1 year, in either group (n=697) or individual (n=523) format. The third arm received usual care (UC; n=522). The primary outcomes were physical activity (mean steps/day) and weight (kg). Secondary outcomes were changes in low-density lipoprotein cholesterol and CVD risk score. We estimated the relative cost-effectiveness of each intervention. RESULTS: At 24 months, the group and individual interventions were not more effective than UC in increasing physical activity (mean difference=70.05 steps, 95% CI -288.00 to 147.90 and mean difference=7.24 steps, 95% CI -224.01 to 238.50, respectively), reducing weight (mean difference=-0.03 kg, 95% CI -0.49 to 0.44 and mean difference=-0.42 kg, 95% CI -0.93 to 0.09, respectively) or improving any secondary outcomes. The group and individual interventions were not cost-effective at conventional thresholds. CONCLUSIONS: Enhancing motivational interviewing with additional behaviour change techniques was not effective in reducing weight or increasing physical activity in those at high CVD risk
Mental defeat is associated with suicide intent in patients with chronic pain
Objective:
Mental defeat has been implicated in precipitating suicide with effects not explained by depression. It has also been found to be elevated in people who are most distressed and disabled by chronic pain. This study examined the role of mental defeat in predicting suicide intent among chronic pain patients and compared the predictive value of mental defeat with other established pain and psychological constructs.
Methods:
Sixty-two chronic pain patients attended a semi-structured interview to assess pain characteristics and suicidality (present and worst-ever) and completed self-report measures of anxiety, depression, hopelessness, self-efficacy, pain catastrophising and mental defeat.
Results:
A total of 22.6% of people reported a history of suicide attempt (1 attempt=12.9%;≥2 attempts=9.7%). The wish to die was reportedly moderate to strong for 63.3% of those who attempted suicide. No significant correlations were found for hopelessness and self-efficacy with suicide intent in this sample. Hierarchical regression analyses suggested that pain intensity was a significant predictor of worst-ever suicidal intent (R=0.11), and mental defeat significantly improved the prediction even when the effect of pain intensity was accounted for (RΔ=0.12). Anxiety, depression and pain catastrophising were significant correlates of suicide intent, but they did not add to the prediction of worst-ever suicide intent after the effect of pain intensity was controlled for.
Discussion:
Mental defeat may be a key indicator for heightened suicide risk. Therapeutic interventions targeting mental defeat offer a novel avenue for reducing suicide risk in chronic pain patients
Enhanced motivational interviewing for reducing weight and increasing physical activity in adults with high cardiovascular risk: the MOVE IT three-arm RCT.
BACKGROUND: Motivational interviewing (MI) enhanced with behaviour change techniques (BCTs) and deployed by health trainers targeting multiple risk factors for cardiovascular disease (CVD) may be more effective than interventions targeting a single risk factor. OBJECTIVES: The clinical effectiveness and cost-effectiveness of an enhanced lifestyle motivational interviewing intervention for patients at high risk of CVD in group settings versus individual settings and usual care (UC) in reducing weight and increasing physical activity (PA) were tested. DESIGN: This was a three-arm, single-blind, parallel randomised controlled trial. SETTING: A total of 135 general practices across all 12 South London Clinical Commissioning Groups were recruited. PARTICIPANTS: A total of 1742 participants aged 40-74 years with a ≥ 20.0% risk of a CVD event in the following 10 years were randomised. INTERVENTIONS: The intervention was designed to integrate MI and cognitive-behavioural therapy (CBT), delivered by trained healthy lifestyle facilitators in 10 sessions over 1 year, in group or individual format. The control group received UC. RANDOMISATION: Simple randomisation was used with computer-generated randomisation blocks. In each block, 10 participants were randomised to the group, individual or UC arm in a 4 : 3 : 3 ratio. Researchers were blind to the allocation. MAIN OUTCOME MEASURES: The primary outcomes are change in weight (kg) from baseline and change in PA (average number of steps per day over 1 week) from baseline at the 24-month follow-up, with an interim follow-up at 12 months. An economic evaluation estimates the relative cost-effectiveness of each intervention. Secondary outcomes include changes in low-density lipoprotein cholesterol and CVD risk score. RESULTS: The mean age of participants was 69.75 years (standard deviation 4.11 years), 85.5% were male and 89.4% were white. At the 24-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA [mean 70.05 steps, 95% confidence interval (CI) -288 to 147.9 steps, and mean 7.24 steps, 95% CI -224.01 to 238.5 steps, respectively] or in reducing weight (mean -0.03 kg, 95% CI -0.49 to 0.44 kg, and mean -0.42 kg, 95% CI -0.93 to 0.09 kg, respectively). At the 12-month follow-up, the group and individual intervention arms were not more effective than UC in increasing PA (mean 131.1 steps, 95% CI -85.28 to 347.48 steps, and mean 210.22 steps, 95% CI -19.46 to 439.91 steps, respectively), but there were reductions in weight for the group and individual intervention arms compared with UC (mean -0.52 kg, 95% CI -0.90 to -0.13 kg, and mean -0.55 kg, 95% CI -0.95 to -0.14 kg, respectively). The group intervention arm was not more effective than the individual intervention arm in improving outcomes at either follow-up point. The group and individual interventions were not cost-effective. CONCLUSIONS: Enhanced MI, in group or individual formats, targeted at members of the general population with high CVD risk is not effective in reducing weight or increasing PA compared with UC. Future work should focus on ensuring objective evidence of high competency in BCTs, identifying those with modifiable factors for CVD risk and improving engagement of patients and primary care. TRIAL REGISTRATION: Current Controlled Trials ISRCTN84864870. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 69. See the NIHR Journals Library website for further project information. This research was part-funded by the NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London
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