Luminescent hyperbolic metasurfaces.

When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells

DLQI scores in vitiligo: reliability and validity of the Persian version

BACKGROUND: The objective of this study was to translate and to test the reliability and validity of the 10-item Dermatology Life Quality Index (DLQI) questionnaire in Iranian patients with vitiligo. METHODS: Using a standard "forward-backward" translation procedure, the English language version of the questionnaire was translated into Persian (the Iranian official language) by two bilinguals. Seventy patients with vitiligo attending the Department of Dermatology, Saadi Hospital, Shiraz, Iran, were enrolled in this study. The reliability and internal consistency of the questionnaire were assessed by Cronbach's alpha coefficient and Spearman's correlation, respectively. Validity was performed using convergent validity. RESULTS: In all, seventy people entered into the study. The mean age of respondents was 28.3 (SD = 11.09) years. Scores on the DLQI ranged from 0 to 24 (mean ± SD, 7.05 ± 5.13). Reliability analysis showed satisfactory result (Cronbach's α coefficient = 0.77). There were no statistically significant differences between daily activity (DA) and personal relationship (PR) scale mean scores in generalized versus focal-segmental involvement in sufferers (P = 0.056, P = 0.053, respectively). There were also strong differences between the mean scores of the PR (personal relationship) scale with the involvement of covered only and covered/uncovered areas (P= 0.016) that was statistically significant in the second group. CONCLUSIONS: The study findings showed that the Persian version of the DLQI questionnaire has a good structural characteristic and is a reliable and valid instrument that can be used for measuring the effects of vitiligo on quality of life

The attitudes of team members towards family presence during hospital-based CPR: A study based in the Muslim setting of four Iranian teaching hospitals

Background: Contrary to international guidelines recommending family presence during cardiopulmonary resuscitation (CPR), allowing family members to be present remains a matter of debate in many countries. The purpose of this study was to determine the opinions of healthcare providers from a Muslim setting concerning family-witnessed resuscitation (FWR). Methods: The sample population consisted of CPR responders in four teaching hospitals in Tehran. These centres have no policy regarding the presence of family members during resuscitation. We developed and circulated a questionnaire gathering opinions, and collated their comments. Results: From 200 respondents, 77 opposed FWR. We found that gender, age, experience, previous exposure to FWR or specialty (except for emergency physicians) did not predict opinion towards family presence during CPR. The most common reasons given for opposition to family presence were fear of psychological trauma to family members, possible interference with patient care/ decision-making, and a perceived increase in staff stress. Conclusion: In a largely Muslim community, and contrary to general guidelines, our survey suggested that the majority of CPR responders do not favour the presence of relatives during cardiopulmonary resuscitation. Any counter to this opinion would need to be based on educating team members about the possible benefits of relatives being present during resuscitation. Public education surrounding CPR would also be a fundamental element for implementing any formal programme encouraging family-witnessed CPR in hospitals such as ours. © 2010 Royal College of Physicians of Edinburgh

Emergency peripartum hysterectomy in a tertiary hospital in Upper Egypt: six years analysis

Background: Emergency peripartum hysterectomy (EPH) is often performed for life-threatening obstetric conditions especially when conservative treatment approach fails to stop postpartum hemorrhage. The aim of the study is to detect the incidence, indications, and complications of EPH over 6 years in Assiut Women Health Hospital in Upper Egypt.Methods: A historical cohort study conducted between January 2009 and December 2014. Detailed review of all files of cases of EPH including maternal age, parity, gestational age, type of delivery, indications for EPH and outcome of the hysterectomy.Results: The overall incidence of EPH was 1.30 per 1,000 deliveries. The main indications for hysterectomies were uterine atony 60 (48.78 %), abnormal placentation 27 (21.95 %) and rupture uterus 25 (20.32 %). There were 48 (39.02%) maternal deaths, while the perinatal mortality was 20.32% (25 cases). Using multivariate logistic regression analysis, we found that woman’s age ≥ 40 years and parity ≥ 5 were the most significant independent predictors for maternal mortality in cases of EPH (OR 5.49; 95% CI 2.16 - 13.96) and (OR 0.34; 95% CI 0.15 - 0.77) respectively.Conclusions: The incidence of EPH in Upper Egypt is high. Uterine atony is the major indication for EPH in our hospital. Late referral and delayed decisions to perform hysterectomy contributes in the high mortality rate

Perturbative Study of Bremsstrahlung and Pair-Production by Spin-1/2 Particles in the Aharonov-Bohm Potential

In the presence of an external Aharonov-Bohm potential, we investigate the two QED processes of the emission of a bremsstrahlung photon by an electron, and the production of an electron-positron pair by a single photon. Calculations are carried out using the Born approximation within the framework of covariant perturbation theory to lowest non-vanishing order in \alpha. The matrix element for each process is derived, and the corresponding differential cross-section is calculated. In the non-relativistic limit, the resulting angular and spectral distributions and some polarization properties are considered, and compared to results of previous works.Comment: 15 pages, RevTex 4, 2 figures, submitted for publicatio

Cardiac-MRI predicts clinical worsening and mortality in pulmonary arterial hypertension: a systematic review and meta-analysis

Objectives This meta-analysis evaluates assessment of pulmonary arterial hypertension (PAH), with a focus on clinical worsening and mortality. Background Cardiac magnetic resonance (CMR) has prognostic value in the assessment of patients with PAH. However, there are limited data on the prediction of clinical worsening, an important composite endpoint used in PAH therapy trials. Methods The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Web of Science databases were searched in May 2020. All CMR studies assessing clinical worsening and the prognosis of patients with PAH were included. Pooled hazard ratios of univariate regression analyses for CMR measurements, for prediction of clinical worsening and mortality, were calculated. Results Twenty-two studies with 1,938 participants were included in the meta-analysis. There were 18 clinical worsening events and 8 deaths per 100 patient-years. The pooled hazard ratios show that every 1% decrease in right ventricular (RV) ejection fraction is associated with a 4.9% increase in the risk of clinical worsening over 22 months of follow-up and a 2.2% increase in the risk of death over 54 months. For every 1 ml/m2 increase in RV end-systolic volume index or RV end-diastolic volume index, the risk of clinical worsening increases by 1.3% and 0.7%, respectively, and the risk of mortality increases by 0.9% and 1%. Every 1 ml/m2 decrease in left ventricular end-systolic volume index or left ventricular end-diastolic volume index increased the risk of death by 2.1% and 2.3%. Left ventricular parameters were not associated with clinical worsening. Conclusions This review confirms CMR as a powerful prognostic marker in PAH in a large cohort of patients. In addition to confirming previous observations that RV function and RV and left ventricular volumes predict mortality, RV function and volumes also predict clinical worsening. This study provides a strong rationale for considering CMR as a clinically relevant endpoint for trials of PAH therapies