Deviation from Snell's Law for Beams Transmitted Near the Critical Angle: Application to Microcavity Lasers

We show that when a narrow beam is incident upon a dielectric interface near the critical angle for total internal reflection it will be transmitted into the far-field with an angular deflection from the direction predicted by Snell's Law, due to a phenomenon we call "Fresnel Filtering". This effect can be quite large for the parameter range relevant to dielectric microcavity lasers.Comment: 4 pages, 3 figures (eps), RevTeX 3.1, to be published in Optics Letter

Severe hypertension and flushing in a patient with a non-metastatic carcinoid tumour

A case of multiple endocrine adenopathy type I associated with a solitary carcinoid tumour is described. During anaesthesia the characteristic syndrome consisting of hypertension, tachycardia and flushing occurred. The possible mechanisms for this are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72985/1/j.1365-2044.1982.tb00995.x.pd

National clinical audit for hospitalised exacerbations of COPD

Introduction: Exacerbations of COPD requiring hospital admission are burdensome to patients and health services. Audit enables benchmarking performance between units and against national standards, and supports quality improvement. We summarise 23 years of UK audit for hospitalised COPD exacerbations to better understand which features of audit design have had most impact. / Method: Pilot audits were performed in 1997 and 2001, with national cross-sectional audits in 2003, 2008 and 2014. Continuous audit commenced in 2017. Overall, 96% of eligible units took part in cross-sectional audit, 86% in the most recent round of continuous audit. We synthesised data from eight rounds of national COPD audit. / Results: Clinical outcomes were observed to change at the same time as changes in delivery of care: length of stay halved from 8 to 4 days between 1997 and 2014, alongside wider availability of integrated care. Process indicators did not generally improve with sequential cross-sectional audit. Under continuous audit with quality improvement support, process indicators linked to financial incentives (early specialist review (55–66%) and provision of a discharge bundle (53–74%)) improved more rapidly than those not linked (availability of spirometry (40–46%) and timely noninvasive ventilation (21–24%)). / Conclusion: Careful piloting and engagement can result in successful roll-out of cross-sectional national audit in a high-burden disease. Audit outcome measures and process indicators may be affected by changes in care pathways. Sequential cross-sectional national audit alone was not generally accompanied by improvements in care. However, improvements in process indicators were seen when continuous audit was combined with quality improvement support and, in particular, financial incentives

National clinical audit for hospitalised exacerbations of COPD

Introduction: Exacerbations of COPD requiring hospital admission are burdensome to patients and health services. Audit enables benchmarking performance between units and against national standards, and supports quality improvement. We summarise 23 years of UK audit for hospitalised COPD exacerbations to better understand which features of audit design have had most impact. Method: Pilot audits were performed in 1997 and 2001, with national cross-sectional audits in 2003, 2008 and 2014. Continuous audit commenced in 2017. Overall, 96% of eligible units took part in cross-sectional audit, 86% in the most recent round of continuous audit. We synthesised data from eight rounds of national COPD audit. Results: Clinical outcomes were observed to change at the same time as changes in delivery of care: length of stay halved from 8 to 4 days between 1997 and 2014, alongside wider availability of integrated care. Process indicators did not generally improve with sequential cross-sectional audit. Under continuous audit with quality improvement support, process indicators linked to financial incentives (early specialist review (55-66%) and provision of a discharge bundle (53-74%)) improved more rapidly than those not linked (availability of spirometry (40-46%) and timely noninvasive ventilation (21-24%)). Conclusion: Careful piloting and engagement can result in successful roll-out of cross-sectional national audit in a high-burden disease. Audit outcome measures and process indicators may be affected by changes in care pathways. Sequential cross-sectional national audit alone was not generally accompanied by improvements in care. However, improvements in process indicators were seen when continuous audit was combined with quality improvement support and, in particular, financial incentives

Effect of time and day of admission on hospital care quality for patients with chronic obstructive pulmonary disease exacerbation in England and Wales: single cohort study

OBJECTIVE: To evaluate if observed increased weekend mortality was associated with poorer quality of care for patients admitted to hospital with chronic obstructive pulmonary disease (COPD) exacerbation. DESIGN: Prospective case ascertainment cohort study. SETTING: 199 acute hospitals in England and Wales, UK. PARTICIPANTS: Consecutive COPD admissions, excluding subsequent readmissions, from 1 February to 30 April 2014 of whom 13 414 cases were entered into the study. MAIN OUTCOMES: Process of care mapped to the National Institute for Health and Care Excellence clinical quality standards, access to specialist respiratory teams and facilities, mortality and length of stay, related to time and day of the week of admission. RESULTS: Mortality was higher for weekend admissions (unadjusted OR 1.20, 95% CI 1.00 to 1.43), and for case-mix adjusted weekend mortality when calculated for admissions Friday morning through to Monday night (adjusted OR 1.19, 95% CI 1.00 to 1.43). Median time to death was 6 days. Some clinical processes were poorer on Mondays and during normal working hours but not weekends or out of hours. Specialist respiratory care was less available and less prompt for Friday and Saturday admissions. Admission to a specialist ward or high dependency unit was less likely on a Saturday or Sunday. CONCLUSIONS: Increased mortality observed in weekend admissions is not easily explained by deficiencies in early clinical guideline care. Further study of out-of-hospital factors, specialty care and deaths later in the admission are required if effective interventions are to be made to reduce variation by day of the week of admission

Gamma (γ) tocopherol upregulates peroxisome proliferator activated receptor (PPAR) gamma (γ) expression in SW 480 human colon cancer cell lines

BACKGROUND: Tocopherols are lipid soluble antioxidants that exist as eight structurally different isoforms. The intake of γ-tocopherol is higher than α-tocopherol in the average US diet. The clinical results of the effects of vitamin E as a cancer preventive agent have been inconsistent. All published clinical trials with vitamin E have used α-tocopherol. Recent epidemiological, experimental and molecular studies suggest that γ-tocopherol may be a more potent chemopreventive form of vitamin E compared to the more-studied α-tocopherol. γ-Tocopherol exhibits differences in its ability to detoxify nitrogen dioxide, growth inhibitory effects on selected cancer cell lines, inhibition of neoplastic transformation in embryonic fibroblasts, and inhibition of cyclooxygenase-2 (COX-2) activity in macrophages and epithelial cells. Peroxisome proliferator activator receptor γ (PPARγ) is a promising molecular target for colon cancer prevention. Upregulation of PPARγ activity is anticarcinogenic through its effects on downstream genes that affect cellular proliferation and apoptosis. The thiazolidine class of drugs are powerful PPARγ ligands. Vitamin E has structural similarity to the thiazolidine, troglitazone. In this investigation, we tested the effects of both α and γ tocopherol on the expression of PPARγ mRNA and protein in SW 480 colon cancer cell lines. We also measured the intracellular concentrations of vitamin E in SW 480 colon cancer cell lines. RESULTS: We have discovered that the α and γ isoforms of vitamin E upregulate PPARγ mRNA and protein expression in the SW480 colon cancer cell lines. γ-Tocopherol is a better modulator of PPARγ expression than α-tocopherol at the concentrations tested. Intracellular concentrations increased as the vitamin E concentration added to the media was increased. Further, γ-tocopherol-treated cells have higher intracellular tocopherol concentrations than those treated with the same concentrations of α-tocopherol. CONCLUSION: Our data suggest that both α and γ tocopherol can upregulate the expression of PPARγ which is considered an important molecular target for colon cancer chemoprevention. We show that the expression of PPARγ mRNA and protein are increased and these effects are more pronounced with γ-tocopherol. γ-Tocopherol's ability to upregulate PPARγ expression and achieve higher intracellular concentrations in the colonic tissue may be relevant to colon cancer prevention. We also show that the intracellular concentrations of γ-tocopherol are several fold higher than α-tocopherol. Further work on other colon cancer cell lines are required to quantitate differences in the ability of these forms of vitamin E to induce apoptosis, suppress cell proliferation and act as PPAR ligands as well as determine their effects in conjunction with other chemopreventive agents. Upregulation of PPARγ by the tocopherols and in particular by γ-tocopherol may have relevance not only to cancer prevention but also to the management of inflammatory and cardiovascular disorders

Stress in nurses : stress-related affect and its determinants examined over the nursing day

Peer reviewedPostprin

(De)synchronization of advanced visual information and ball flight characteristics constrains emergent information–movement couplings during one-handed catching

Advance visual information of a projection action and ball flight information is important for organizing dynamic interceptive actions like catching. However, how the central nervous system (CNS) manages the relationship between advance visual information and emerging ball flight information in regulating behavior is less well understood. Here, we sought to examine the extent that advance visual information to the CNS constrains regulation of catching actions by synchronizing and desynchronizing its relationship with ball trajectory characteristics. Novel technology was used to present video footage of an actor throwing a ball at three different speeds, integrated with information from a real ball projected by a machine set to the three speeds. The technology enabled three synchronized and six desynchronized conditions between advance visual information and subsequent ball flight trajectories. Catching performance, kinematic data from the catching hand and gaze behaviors were recorded. Findings revealed that desynchronization of video images of ball projection shaped emergent catching behaviors. Footage of slower throws, paired with faster ball projection speeds, caused catching performance decrements. Timing in early phases of action was organized by the CNS to match the advance visual information presented. In later phases, like the grasp, ball flight information constraints adapted and regulated behaviors. Gaze behaviors showed increased ball projection speed resulted in participants tracking the ball for a smaller percentage of ball flight. Findings highlighted the role of the two visual systems in perception and action, implicating the importance of coupling advanced visual information and ball flight to regulate emergent movement coordination tendencies during interceptive behaviors