Understanding the limits of plasmonic enhancement in organic photovoltaics

Plasmonic enhancement in organic photovoltaics has been extensively studied in the past decade. However, the reported improvements in power conversion efficiency (PCE) are highly inconsistent due to a poor understanding of the limitations of how plasmonics affect charge generation and transport in solar cells. In this work, we address these long-standing uncharted questions as to when plasmonic enhancements are useful and when they are not. We do this with a model system consisting of poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)]:[6,6]-phenyl C61 butyric acid methyl ester PCDTBT polymer active layer with silver nanostructures embedded in the poly(3,4-ethylenedioxythiophene):polystyrene PEDOT:PSS sulfonate hole-transport layer. We demonstrate that: (a) plasmonic enhancements are most pronounced when the charge carrier mobilities of the donor and acceptor materials are unbalanced; (b) the introduction of plasmonic nanostructures in devices with balanced charge transport usually results in a decrease in efficiency; (c) plasmonic enhancement is highly shape-dependent; (d) for devices with asymmetric mobilities, as long as the species with low mobility is extracted at the contact where light is incident, device efficiency will be boosted; and (e) increase in light absorption in the active layer has minimal impact on PCE; the efficiency is primarily driven by exciton generation and charge collection efficiency. The findings of our work provide a generalized framework to guide researchers as to when plasmonic effects could be helpful to a device and when they could degrade performance

Recognition, Investigation, and Control of Communicable-Disease Outbreaks in Child Day-Care Settings

As increasing numbers of young children attend day-care centers in the US, the elevated risk of acquiring infectious diseases in this setting has emerged as an important public health issue.1 Outbreaks of infectious diseases occur frequently within the daycare setting,2 and enteric and respiratory pathogens may be readily transmitted to household members and others in the community.1,2 The economic burden of these outbreaks is considerable; for example, parents of children in day care miss an average of I to 4 weeks of work each year to care for their sick children.1 Investigations of communicable-disease outbreaks in day-care centers have provided a wealth of information useful in developing and implementing infection-control policies and guidelines. While documented experiences with outbreaks in day-care settings have been relatively recent, they have rapidly expanded our understanding of reservoirs of infectious agents, routes of transmission, clinical characteristics of illness, risk factors for infection, the effectiveness of interventions, and recognition of pathogens previously not reportable or thought to be unimportant. Outbreak investigations in day-care centers reported in the literature have focused primarily on the etiologic agents listed in the Table. The purpose of this paper is to provide a brief overview of methodologic issues pertinent to such investigations

Recognition, Investigation, and Control of Communicable-Disease Outbreaks in Child Day-Care Settings

As increasing numbers of young children attend day-care centers in the US, the elevated risk of acquiring infectious diseases in this setting has emerged as an important public health issue.1 Outbreaks of infectious diseases occur frequently within the daycare setting,2 and enteric and respiratory pathogens may be readily transmitted to household members and others in the community.1,2 The economic burden of these outbreaks is considerable; for example, parents of children in day care miss an average of I to 4 weeks of work each year to care for their sick children.1 Investigations of communicable-disease outbreaks in day-care centers have provided a wealth of information useful in developing and implementing infection-control policies and guidelines. While documented experiences with outbreaks in day-care settings have been relatively recent, they have rapidly expanded our understanding of reservoirs of infectious agents, routes of transmission, clinical characteristics of illness, risk factors for infection, the effectiveness of interventions, and recognition of pathogens previously not reportable or thought to be unimportant. Outbreak investigations in day-care centers reported in the literature have focused primarily on the etiologic agents listed in the Table. The purpose of this paper is to provide a brief overview of methodologic issues pertinent to such investigations

Orthopedic management of the extremities in patients with Morquio A syndrome.

BackgroundMusculoskeletal involvement in Morquio A syndrome (mucopolysaccharidosis IVA; MPS IVA) contributes significantly to morbidity and mortality. While the spinal manifestations of the disorder have received considerable attention in the literature, there have been few reported studies to date to guide the management of the orthopedic problems associated with the lower and upper extremities.PurposeThe objective was to develop recommendations for the management of the extremities in patients with Morquio A syndrome.MethodsA group of specialists in orthopedics, pediatrics and genetics with experience in the management of Morquio A patients convened to review and discuss current clinical practices and to develop preliminary recommendations. Evidence from the literature was retrieved. Recommendations were further refined until consensus was reached.Results and conclusionsThis present article provides a detailed review and discussion of the lower and upper extremity deformities in Morquio A syndrome and presents recommendations for the assessment and treatment of these complications. Key issues, including the importance of early diagnosis and the implications of medical therapy, are also addressed. The recommendations herein represent an attempt to develop a uniform and practical approach to managing patients with Morquio A syndrome and improving their outcomes

Locations of marine animals revealed by carbon isotopes

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available

Endothelium-derived contraction in a model of rheumatoid arthritis is mediated via angiotensin II type 1 receptors

A role for endothelium-derived constricting factors (EDCF), and the angiotensin II type 1 receptor (AT1R) pathway, in the vascular impairment found in the rat Freund's complete adjuvant (FCA)-model of rheumatoid arthritis (RA) was examined. FCA arthritis was induced in rats±losartan. Vehicle-treated rats served as controls. Knee-joint swelling and red blood cell (RBC) aggregation were measured as indicators of inflammation and endothelium reactivity assessed by response to acetylcholine (ACh) on aortic rings. Results show that knee-joint swelling and RBC aggregation were elevated in the FCA+vehicle group and restored to control levels in the FCA+losartan-treated animals. ACh-induced relaxation of aortic rings taken from FCA+vehicle animals was significantly impaired compared to vehicle-controls and this vasoreactivity was restored to control levels in the FCA+losartan-treated group. Further examination of aorta from the FCA+vehicle animals revealed an EDCF that was reliant on cyclooxygenase-2 (but not cyclooxygenase-1), generation of superoxide anion generation (but not hydrogen peroxide) and activation of thromboxane-prostanoid receptor. Losartan administration in vivo or ex vivo (to aortic rings) prevented the generation of the EDCF. In summary, this is the first evidence of an EDCF in a model of RA and identifies this mechanism as potentially significant in the cardiovascular disorder associated with the disease

The Houses of Parliament and Reid's Inquiries into User Perception

This paper provides a brief overview of the role of user perception in the development of Reid ventilation system for the Palace of Westminster. User-perception was used as a performance indicator in the day-to-day management of the ventilation, but also it was also a major design factor underlying the development of the ventilation system for the Permanent Houses of Commons

Oral rehydration versus intravenous therapy for treating dehydration due to gastroenteritis in children: a meta-analysis of randomised controlled trials

BACKGROUND: Despite treatment recommendations from various organizations, oral rehydration therapy (ORT) continues to be underused, particularly by physicians in high-income countries. We conducted a systematic review of randomised controlled trials (RCTs) to compare ORT and intravenous therapy (IVT) for the treatment of dehydration secondary to acute gastroenteritis in children. METHODS: RCTs were identified through MEDLINE, EMBASE, CENTRAL, authors and references of included trials, pharmaceutical companies, and relevant organizations. Screening and inclusion were performed independently by two reviewers in order to identify randomised or quasi-randomised controlled trials comparing ORT and IVT in children with acute diarrhea and dehydration. Two reviewers independently assessed study quality using the Jadad scale and allocation concealment. Data were extracted by one reviewer and checked by a second. The primary outcome measure was failure of rehydration. We analyzed data using standard meta-analytic techniques. RESULTS: The quality of the 14 included trials ranged from 0 to 3 (Jadad score); allocation concealment was unclear in all but one study. Using a random effects model, there was no significant difference in treatment failures (risk difference [RD] 3%; 95% confidence intervals [CI]: 0, 6). The Mantel-Haenzsel fixed effects model gave a significant difference between treatment groups (RD 4%; 95% CI: 2, 5) favoring IVT. Based on the four studies that reported deaths, there were six in the IVT groups and two in ORT. There were no significant differences in total fluid intake at six and 24 hours, weight gain, duration of diarrhea, or hypo/hypernatremia. Length of stay was significantly shorter for the ORT group (weighted mean difference [WMD] -1.2 days; 95% CI: -2.4,-0.02). Phlebitis occurred significantly more often with IVT (number needed to treat [NNT] 33; 95% CI: 25,100); paralytic ileus occurred more often with ORT (NNT 33; 95% CI: 20,100). These results may not be generalizable to children with persistent vomiting. CONCLUSION: There were no clinically important differences between ORT and IVT in terms of efficacy and safety. For every 25 children (95% CI: 20, 50) treated with ORT, one would fail and require IVT. The results support existing practice guidelines recommending ORT as the first course of treatment in appropriate children with dehydration secondary to gastroenteritis