Controlling Phase Transitions in Two-Dimensional Perovskites through Organic Cation Alloying.

We demonstrate control over the phase transition temperature of Ruddlesden-Popper two-dimensional (2D) perovskites by alloying alkyl organic cations of varying lengths. By blending hexylammonium with pentylammonium or heptylammonium cations in different ratios, we continuously tune the phase transition temperature of 2D perovskites from approximately 40 to -80 °C in both crystalline powders and thin films. Correlating temperature-dependent grazing incidence wide-angle X-ray scattering and photoluminescence spectroscopy, we also demonstrate that the phase transition in the organic layer couples to the inorganic lattice, impacting PL intensity and wavelength. We take advantage of changes in PL intensity to image the dynamics of this phase transition and show asymmetric phase growth at the microscale. Our findings provide the necessary design principles to precisely control phase transitions in 2D perovskites for applications such as solid-solid phase change materials and barocaloric cooling.

Dynamic outcome prediction in a socio-demographically diverse population-based cohort of extremely preterm neonates.

OBJECTIVE: Accurate outcome prediction is crucial for counseling parents and providing individualized treatment to extremely premature infants. We sought to improve upon existing prediction model by using a diverse population-based cohort of extremely premature live births (⩽28 weeks' gestation) for survival and survival without severe neonatal morbidity at different times throughout the first week of life and to evaluate potential differences by race/ethnicity and maternal education. STUDY DESIGN: Retrospective cohort study of all California live births from 2007 through 2011 with linked birth, death and hospital discharge records. RESULTS: A total of 6009 infants were included. In the validation data set at time of delivery, the area under the receiver-operating characteristic curve for the model containing all predictors was 0.863 for survival and 0.789 for survival without severe morbidity. The marginal probability of survival without severe neonatal morbidity of an Asian infant born to a mother with <12 years of education compared with the reference (Caucasian infant, mother with ⩾12 years of education) was -0.23 (95% confidence interval (CI) -0.31 to -0.15) for all infants at time of birth and -0.28 (95% CI -0.39 to -0.18) for infants with attempted resuscitation. Notably, no other differences by racial/ethnic category and maternal education emerged. CONCLUSIONS: Probabilities of survival and survival without major morbidity change rapidly throughout the first week of life. Extremely premature infants born to Asian mothers with less than a high school education appear to have a lower probability to survive without significant morbidity compared with their Caucasian peers.

Population-based risks of mortality and preterm morbidity by gestational age and birth weight.

OBJECTIVE: The objective of this study is to examine the effect of small or large for gestational age (SGA/LGA) status on mortality and morbidity by gestational age. STUDY DESIGN: Logistic binomial regression was used to calculate relative risks (RRs) and 95% confidence intervals for infant mortality and preterm morbidities for SGA or LGA compared with appropriately grown (AGA) deliveries stratified by gestational age group. RESULTS: Compared with AGA infants of similar gestational age, SGA infants were at increased risk for infant mortality. Mortality risk was decreased for LGA infants born between 25 and 27 weeks (RR: 0.6) but increased for LGA infants born between 28 and 31 weeks (RR: 1.9). Risk of preterm morbidity was increased for SGA infants born between 28 and 38 weeks, but decreased for LGA infants born before 37 weeks. CONCLUSION: This study demonstrates the importance of considering birth weight for gestational age when evaluating morbidity and mortality risks.

Twin-reversed arterial perfusion sequence associated with decreased fetal cerebral vascular impedance.

OBJECTIVES: Twin-reversed arterial perfusion (TRAP) sequence affects 1% of monochorionic twin pregnancies and is caused by abnormal vascular connections between a pump twin and an acardiac mass. The effects of abnormal vascular connections on cerebral vasculature in the pump twin are unknown. We hypothesize that abnormal cerebral vascular impedance, as assessed by the pulsatility index (PI), is present in pump twins and that fetal intervention alters cerebral impedance. METHODS: Fetal echocardiograms performed between 2010 and 2013 in pregnancies diagnosed with TRAP (n = 19), recorded at presentation, and uncomplicated monochorionic twin pregnancies (controls, n = 18; 36 fetuses) were analyzed. In all subjects, the middle cerebral artery (MCA)-PI, combined cardiac output (CCO) and cardiothoracic ratio were calculated, and the values for cases and controls were compared. RESULTS: The mean gestational age at the time of echocardiography was 20 weeks in both groups. MCA-PI was lower in TRAP cases than in controls (1.55 (95% CI, 1.47-1.64) vs 1.74 (95% CI, 1.65-1.82), respectively; P = 0.004). CCO in TRAP cases was mildly elevated for gestational age (199.7 (95% CI, 138.4-261.1) mL/min) compared with that of controls (131.4 (95% CI, 102.2-160.7) mL/min). In six TRAP cases with a second echocardiogram available, the mean MCA-PI increased after intervention, from 1.5 (95% CI, 1.3-1.7) to 1.8 (95% CI, 1.4-2.2). CONCLUSIONS: TRAP pump twins have lower cerebral vascular impedance than do controls, suggestive of a brain-sparing effect. MCA-PI appeared to increase in a small group of pump twins after intervention. These findings suggest a fetal cerebral autoregulatory response to a high cardiac output state that begins to change after fetal intervention. The long-term implications for neurodevelopmental outcome warrant further study.

Antenatal antibiotic exposure in preterm infants with necrotizing enterocolitis.

OBJECTIVE: To determine whether an association exists between antenatal antibiotic exposure and incidence of necrotizing enterocolitis (NEC) in low birth weight infants. STUDY DESIGN: A retrospective case-control study was performed on all infants with a diagnosis of NEC born at our institition between 1988 and 2006. Medical histories of all infants with a diagnosis of NEC ≥Bell's stage IIA and matched controls without NEC were reviewed. Maternal and neonatal characteristics were compared using the Mantel-Haenszel chi-square procedure, and logistic regression models were constructed to account for confounding. RESULT: Clinical data for 97 matched pairs were analyzed. The adjusted odds ratio (OR) for antenatal exposure to ampicillin was significantly greater for infants who developed NEC (OR 2.3, 95% confidence interval 1.1, 4.8, P=0.003) than for control infants. CONCLUSION: Infants who developed NEC were more likely to have a history of in utero exposure to ampicillin in the immediate antepartum period than infants who did not develop NEC.

Iyengar Yoga versus Enhanced Usual Care on Blood Pressure in Patients with Prehypertension to Stage I Hypertension: a Randomized Controlled Trial.

The prevalence of prehypertension and Stage 1 hypertension continues to increase despite being amenable to non-pharmacologic interventions. Iyengar yoga (IY) has been purported to reduce blood pressure (BP) though evidence from randomized trials is lacking. We conducted a randomized controlled trial to assess the effects of 12 weeks of IY versus enhanced usual care (EUC) (based on individual dietary adjustment) on 24-h ambulatory BP in yoga-naïve adults with untreated prehypertension or Stage 1 hypertension. In total, 26 and 31 subjects in the IY and EUC arms, respectively, completed the study. There were no differences in BP between the groups at 6 and 12 weeks. In the EUC group, 24-h systolic BP (SBP), diastolic BP (DBP) and mean arterial pressure (MAP) significantly decreased by 5, 3 and 3 mmHg, respectively, from baseline at 6 weeks (P < .05), but were no longer significant at 12 weeks. In the IY group, 24 h SBP was reduced by 6 mmHg at 12 weeks compared to baseline (P = .05). 24 h DBP (P < .01) and MAP (P < .05) decreased significantly each by 5 mmHg. No differences were observed in catecholamine or cortisol metabolism to explain the decrease in BP in the IY group at 12 weeks. Twelve weeks of IY produces clinically meaningful improvements in 24 h SBP and DBP. Larger studies are needed to establish the long term efficacy, acceptability, utility and potential mechanisms of IY to control BP.

Effect of selective fetoscopic laser photocoagulation therapy for twin-twin transfusion syndrome on pulmonary valve pathology in recipient twins.

OBJECTIVE: To investigate the impact of selective fetoscopic laser photocoagulation (SFLP) on pre-existing pulmonary valve pathology in the recipient twin in twin-twin transfusion syndrome (TTTS). METHODS: We evaluated preoperative echocardiograms of all pregnancies with TTTS treated with SFLP at our institution from 2001 to 2009 (n = 76). Sixteen (21%) recipients had an abnormal pulmonary valve (stenosis/dysplasia, insufficiency or functional atresia) before SFLP. Postoperative echocardiograms and medical records from these 16 recipients were reviewed. Changes in pulmonary valve structure and function, and overall cardiac function, were noted after SFLP. RESULTS: The mean gestational age at SFLP was 21 (range, 18.7-24.3) weeks. Seven of sixteen (44%) recipients with abnormal pulmonary valve prior to SFLP survived. Six of the 16 (37.5%) recipient twins had documented absence of persistent pulmonary valve abnormalities at birth or at autopsy. Two (12.5%) of the 16 recipients (2.6% of the original cohort) had persistent pulmonary valve abnormalities at birth, requiring intervention. Systolic and diastolic function improved or normalized after SFLP in all patients undergoing longitudinal follow-up. There was a tendency for a better cardiovascular profile score (best = 10 points) at initial evaluation in pregnancies with survivors compared with those with no survivors (mean (SD): 5.6 (2.2) vs. 6.75 (1.28)), but this was not statistically significant. Severity of cardiac involvement did not predict persistence of valve pathology or survival. CONCLUSIONS: SFLP can improve flow through the pulmonary valve of the recipient twin in TTTS, probably as a consequence of improvements in right ventricular systolic and diastolic function. However, pulmonary valve pathology may persist and require postnatal intervention.

Public health triangulation: approach and application to synthesizing data to understand national and local HIV epidemics.

BACKGROUND: Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and meta-analysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. METHODS: The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. RESULTS: Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. CONCLUSIONS: Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.

Mortality rate of bullous pemphigoid in a US medical center.

All patients at the Medical College of Wisconsin Affiliated Hospitals with a new diagnosis of bullous pemphigoid (BP) between May 1, 1997 and September 1, 2002 were included in this study. The age at onset, date of death or date of last follow-up visit, mode of treatment, co-morbidities, and initial and follow-up hospitalizations were noted. Thirty-eight new patients were identified and complete follow-up data were obtained on 37 of the patients. Patients were followed a minimum of 1 y or until the time of death. The mean duration of follow-up was 20 mo. Kaplan-Meier analysis of our population indicated a 1-y survival probability of 88.96% (standard error 5.21%), with a 95% confidence interval (75.6%, 94.2%). This survival rate was considerably higher than that recently reported in several studies from Europe (29%-41% first year mortality). Although the age at onset and co-morbidities of our patients were similar to those in the European studies, the rate of hospitalization of our patients was much lower than that of patients from Europe (1.5 d per patient vs 11-25 d per patient). This study suggests that differences in practice patterns may be an important factor in the reduced mortality rate in US BP patients compared with Europe.

Population-level HIV declines and behavioral risk avoidance in Uganda.

Uganda provides the clearest example that human immunodeficiency virus (HIV) is preventable if populations are mobilized to avoid risk. Despite limited resources, Uganda has shown a 70% decline in HIV prevalence since the early 1990s, linked to a 60% reduction in casual sex. The response in Uganda appears to be distinctively associated with communication about acquired immunodeficiency syndrome (AIDS) through social networks. Despite substantial condom use and promotion of biomedical approaches, other African countries have shown neither similar behavioral responses nor HIV prevalence declines of the same scale. The Ugandan success is equivalent to a vaccine of 80% effectiveness. Its replication will require changes in global HIV/AIDS intervention policies and their evaluation.

AIDS communications through social networks: catalyst for behaviour changes in Uganda.

OBJECTIVE: To investigate distinctive communications through social networks which may be associated with population behaviour changes and HIV prevalence declines in Uganda compared to other countries. METHODS: We undertook a comparative analysis of demographic and HIV behavioural data collected in Demographic and Health Surveys (DHS III) in Uganda, Kenya, Tanzania, Malawi, Zambia and Zimbabwe as well as Knowledge, Attitudes and Behaviours (KABP) surveys in Uganda in 1989 and 1995. AIDS behaviours, social communications and channels for communication about AIDS and people with AIDS were analysed by age, sex and country. Modelling was developed to investigate at what stage of the epidemic a majority of people will know someone with AIDS, given differing communication patterns through social networks. Finally AIDS reporting and Voluntary Counselling and Testing (VCT) trends were analysed to assess if the impact of social communications worked through clinical services and interventions or more directly at the population level in community contexts. RESULTS: Uganda showed unique patterns of communications through social networks including a shift from mass and institutional to personal channels for communicating about AIDS, 1989-1995. This was associated with higher levels of knowing someone with AIDS through social networks and, in turn, positive risk ratios for behaviour change including reducing casual sex and condom use. Youth had distinctively high levels of knowing someone with AIDS in Uganda, suggesting widespread community communication across age groups. Patterns of disclosure, AIDS diagnosis and reporting were influential on social communications about AIDS. Over 90%, 45% or under 20% of people know someone with AIDS at peak HIV incidence and high AIDS mortality, depending on whether communications through social networks are extensive or restricted. CONCLUSION: There are distinctive patterns for communicating through social networks about AIDS and people with AIDS in Uganda. They appear to work directly at population level rather than in response to clinical interventions and testing and may be important in the uptake of the latter services. This communication response provides an important basis for HIV prevention if it is to be scaled to the population level. Vertical prevention (and even treatment) interventions need to engage more closely with local, horizontal communication and behavioural responses to AIDS. Communication programmes have to take root at the level of social networks working though local networks of meetings, chiefs, churches and health personnel as well as the media. Mobilising basic social communications may be a necessary resource (as much as services and finance) to scale HIV prevention and treatment to the population level.

Behaviour and communication change in reducing HIV: is Uganda unique?

The clearest example of declines in HIV prevalence and changes in sexual behaviour comes from Uganda. Are there lessons to learn for other countries or is Uganda unique? In this paper, we assess the epidemiological and behavioural data on Uganda comparatively to other African countries and then analyse data from other populations where HIV has declined. In Uganda, HIV prevalence declined from 21% to 9.8% from 1991-1998, there was a reduction in non-regular sexual partners by 65% and greater levels of communication about AIDS and people with AIDS through social networks, unlike the comparison countries. There is evidence of a basic population level response initiated at community level, to avoid risk, reduce risk behaviours and care for people with AIDS. The basic elements-a continuum of communication, behaviour change and care-were integrated at community level. They were also strongly supported by distinctive Ugandan policies from the 1980s. We identify a similar, early behaviour and communication response in other situations where HIV has declined: Thailand, Zambia and the US Gay community. In Thailand, visits to sex workers decreased by 55% and non-regular partners declined from 28% to 15% (1990-1993): as important as the '100% condom use policy'. Similarly, in Zambia and Ethiopia risk behaviour has decreased and analysis of Sexually Transmitted Disease (STD) rates among Gay populations in the USA shows a decline from as early as 1985 in White Gay populations, with later declines in Hispanic and Black Gay populations. These responses preceded and exceeded HIV prevention. However, where they were built on by distinctive HIV policies, HIV prevention has been scaled and led to national level declines in HIV. It is not easy to transfer the lessons of these successes. They require real social and political capital in addition to financial capital. Nevertheless, similar characteristics are present in community responses in Africa, Asia and USA, and even in fragmented signs of HIV declines in other African cities. Only in a few situations has this behaviour and communication process been recognised, mobilised and built on by HIV prevention policy. Where this has occurred, HIV prevention success has been greater than biomedical approaches or methods introduced from outside. It represents a social vaccine for HIV from Africa, and is available now.

Outcomes of posterolateral versus BAK titanium cage interbody lumbar fusion in injured workers: a retrospective cohort study.

Lumbar fusion has been criticized for variable patient outcomes, though little is known regarding how outcomes vary across procedures. We examined outcomes of posterolateral versus BAK interbody lumbar fusion in workers' compensation cases. A medical record review and a follow-up survey were completed. The sample included 185 posterolateral and 185 lumbar interbody fusions. An outcome survey was conducted an average of 5 years after surgery. Arthrodesis rates, satisfaction, function, and health were better for the BAK interbody lumbar fusion cohort. Results suggest greater efficacy of the BAK interbody approach over posterolateral approaches to lumbar fusion in compensated patients.

Maternal leptin receptor gene variant Gln223Arg is not associated with variation in birth weight or maternal body mass index in UK and South Asian populations.

BACKGROUND: Leptin is an adipocyte secreted hormone involved in regulation of body weight and metabolism in man. Placenta leptin levels correlate positively with birth weight. It is therefore possible that variation in the leptin receptor gene (LEPR) may contribute to obesity and influence birth weight. OBJECTIVE: This study investigates the influence of the leptin receptor gene variant Gln223Arg (A-->G, 668), on maternal body mass index (BMI), foetal gestational length and birth weight in a cohort of 455 healthy pregnant women of Asian Indian (India, Bangladesh, Pakistan) and UK/Irish origin. RESULTS: Maternal genotype distributions did not differ from those expected under Hardy-Weinberg equilibrium conditions in either population of origin. Maternal genotype for the Gln223Arg leptin receptor gene polymorphism showed no significant association with foetal birth weight (adjusted for gestational length) or with maternal BMI during first trimester (adjusted for age) in either population group. CONCLUSION: These results suggest that the Gln223Arg variant in the maternal leptin receptor gene does not explain the association between placental leptin levels and birth weight, and is not associated with variation in maternal BMI in early pregnancy in our sample.

Post-term induction of labor revisited.

Post-term pregnancy (longer than 42 weeks or 294 days) occurs in approximately 10% of all singleton gestations. The adverse outcomes of post-term pregnancy include a substantial increase in perinatal mortality and morbidity. ACOG currently recommends induction of labor for low-risk pregnancy during the 43rd week of gestation. However, that recommendation dates from 1989. Recent reports mandate reconsideration of the management of post-term pregnancy, including reinterpretation of the statistical risk of stillbirth in post-term pregnancies using ongoing (undelivered) rather than delivered pregnancies as the denominator, which shows a far higher risk to post-term fetuses than believed. Recent data also suggest that the risk of cesarean delivery after induction of labor at term is lower than reported, possibly because of improvements in methods for cervical ripening. Those findings provide rationale for earlier labor induction in low-risk pregnancies.

Association of the TNF-alpha-308 (G-->A) polymorphism with self-reported history of childhood asthma.

Asthma is a complex disease involving genetic and environmental aetiology. The tumour necrosis factor-alpha (TNF-alpha) and angiotensin-converting enzyme (ACE) genes have been implicated in asthma pathogenesis. This study investigated the association of a G-308A variant of TNF-alpha and an insertion/deletion (I/D) variant of ACE with a self-reported history of childhood asthma, in two population groups. At Northwick Park Hospital, London, 1,811 pregnant women attending for antenatal care were recruited. Participants with a self-reported history of childhood asthma, determined by a researcher-administered questionnaire, and controls with no personal or family history of asthma, of UK/Irish (cases n=20; controls n=416) and South Asian (cases n=6; controls n=275) origin were used in this study. Participants were genotyped for the TNF-alpha-308 and ACE I/D variants by a PCR-RFLP and PCR approach. The TNF-alpha-308 allele 2 (-308A) was significantly associated with self-reported childhood asthma in the UK/Irish (Odds ratios (OR): 2.6; 95% confidence intervals (CI): 1.1-6.2; P=0.03) but not in the South Asian population. The ACE DD genotype was not associated with childhood asthma in either population group. Gametic phase disequilibrium between the TNF-alpha-308 and ACE I/D variants was significantly different from zero in UK/Irish cases (delta=0.09; P=0.034). The TNF-alpha308 allele 2 or a linked major histocompatibility complex (MHC) variant may be a genetic risk factor for childhood asthma in the UK/Irish sample.

Anterior clinoid mucocele masquerading as retrobulbar neuritis.

Mucoceles arising from the anterior clinoid is rare. Although intrinsically benign, mucoceles in the sphenoid sinus (anterior clinoid variant) can lead to complications due to their proximity to other structures. We present a case of a young man whose visual complaints were typical for retrobulbar optic neuritis. Results of radiologic tests for diagnosis led us to the early detection of a surgically treatable condition, a sphenoid sinus mucocele (anterior clinoid variant). Early surgery was helpful in ameliorating the symptoms, leading to full recovery of visual function. The clinician should be aware of this rare entity with its presentation in a wide variety of signs and symptoms.