Nurse understaffing associated with adverse outcomes for surgical admissions.

BACKGROUND: Nurses play a crucial role in maintaining the safety of surgical patients. Few nurse staffing studies have looked specifically at surgical patients to examine the impact of exposure to low staffing on patient outcomes. METHODS: A longitudinal patient analysis was conducted in four organizations in England using routine data from 213 910 admissions to all surgical specialties. Patients' staffing exposures were modelled as counts of understaffed registered nurse and nurse assistant days in the first 5 inpatient days. Understaffing was identified when staffing per patient-day was below the mean for the ward. Cox models were used to examine mortality within 30 days of admission and readmission within 30 days of discharge. Generalized linear models were used to investigate duration of hospital stay and occurrence of hospital-acquired conditions. RESULTS: Increased exposure to registered nurse understaffing was associated with longer hospital stay and increased risk of deep vein thrombosis, pneumonia, and pressure ulcers. This was also true for nurse assistant understaffing, but the effect sizes tended to be smaller. In the Cox models, there were similarly increased hazards of death for registered nurse understaffing (HR 1.09, 95% c.i. 1.07 to 1.12) and nurse assistant understaffing (HR 1.10, 1.08 to 1.13), whereas the effect size of registered nurse understaffing for readmission (HR 1.02, 1.02 to 1.03) was greater than that seen with nurse assistants (HR 1.01, 1.01 to 1.02). CONCLUSION: Understaffing by both registered nurses and nursing assistants is associated with increased risks of a range of adverse events, and generally larger effects are seen with registered nurse understaffing.

The association between midwifery staffing and reported harmful incidents: a cross-sectional analysis of routinely collected data.

BACKGROUND: Independent inquiries have identified that appropriate staffing in maternity units is key to enabling quality care and minimising harm, but optimal staffing levels can be difficult to achieve when there is a shortage of midwives. The services provided and how they are staffed (total staffing, skill-mix and deployment) have been changing, and the effects of workforce changes on care quality and outcomes have not been assessed. This study aims to explore the association between daily midwifery staffing levels and the rate of reported harmful incidents affecting mothers and babies. METHODS: We conducted a cross-sectional analysis of daily reports of clinical incidents in maternity inpatient areas matched with inpatient staffing levels for three maternity services in England, using data from April 2015 to February 2020. Incidents resulting in harm to mothers or babies was the primary outcome measure. Staffing levels were calculated from daily staffing rosters, quantified in Hours Per Patient Day (HPPD) for midwives and maternity assistants. Understaffing was defined as staffing below the mean for the service. A negative binomial hierarchical model was used to assess the relationship between exposure to low staffing and reported incidents involving harm. RESULTS: The sample covered 106,904 maternal admissions over 46 months. The rate of harmful incidents in each of the three services ranged from 2.1 to 3.0 per 100 admissions across the study period. Understaffing by registered midwives was associated with an 11% increase in harmful incidents (adjusted IRR 1.110, 95% CI 1.002,1.229). Understaffing by maternity assistants was not associated with an increase in harmful incidents (adjusted IRR 0.919, 95% 0.813,1.039). Analysis of specific types of incidents showed no statistically significant associations, but most of the point estimates were in the direction of increased incidents when services were understaffed. CONCLUSION: When there is understaffing by registered midwives, more harmful incidents are reported but understaffing by maternity assistants is not associated with higher risk of harms. Adequate registered midwife staffing levels are crucial for maintaining safety. Changes in the profile of maternity service workforces need to be carefully scrutinised to prevent mothers and babies being put at risk of avoidable harm.

Systematic in situ hydration neutron reflectometry study on Nafion thin films.

Reported herein is a neutron reflectometry (NR) study on hydrated Nafion thin films (∼30 nm) on a silicon substrate with native oxide. The Nafion morphology is investigated systematically across the whole relative humidity range using both H2O and D2O vapours to enable a comparative study. By utilising this systematic approach two key results have been obtained. The first is that by leveraging the strong positive scattering signal from the D2O vapour, a complete and systematic water adsorption isotherm (Type II) for a Nafion thin film is produced. Utilising the slight negative scattering signal of the H2O enabled the quantification of the hydration dependent evolution of the formation of Nafion/water lamellae near the substrate surface. The number of lamellae layers increases continuously with hydration, and does not form abruptly. We also report the effects of swelling on the thin films across the relative humidity ranges. The work reported should prove useful in quantifying other hydration dependent properties of Nafion thin films such as conductivity and understanding Nafion/semiconductor based devices, as well as showcasing a NR methodology for other hydrophilic polymers.

Detecting Deteriorating Patients in the Hospital: Development and Validation of a Novel Scoring System.

Rationale: Late recognition of patient deterioration in hospital is associated with worse outcomes, including higher mortality. Despite the widespread introduction of early warning score (EWS) systems and electronic health records, deterioration still goes unrecognized. Objectives: To develop and externally validate a Hospital- wide Alerting via Electronic Noticeboard (HAVEN) system to identify hospitalized patients at risk of reversible deterioration. Methods: This was a retrospective cohort study of patients 16 years of age or above admitted to four UK hospitals. The primary outcome was cardiac arrest or unplanned admission to the ICU. We used patient data (vital signs, laboratory tests, comorbidities, and frailty) from one hospital to train a machine-learning model (gradient boosting trees). We internally and externally validated the model and compared its performance with existing scoring systems (including the National EWS, laboratory-based acute physiology score, and electronic cardiac arrest risk triage score). Measurements and Main Results: We developed the HAVEN model using 230,415 patient admissions to a single hospital. We validated HAVEN on 266,295 admissions to four hospitals. HAVEN showed substantially higher discrimination (c-statistic, 0.901 [95% confidence interval, 0.898-0.903]) for the primary outcome within 24 hours of each measurement than other published scoring systems (which range from 0.700 [0.696-0.704] to 0.863 [0.860-0.865]). With a precision of 10%, HAVEN was able to identify 42% of cardiac arrests or unplanned ICU admissions with a lead time of up to 48 hours in advance, compared with 22% by the next best system. Conclusions: The HAVEN machine-learning algorithm for early identification of in-hospital deterioration significantly outperforms other published scores such as the National EWS.

The association between ward staffing levels, mortality and hospital readmission in older hospitalised adults, according to presence of cognitive impairment: a retrospective cohort study.

BACKGROUND: Lower nurse staffing levels are associated with increased hospital mortality. Older patients with cognitive impairments (CI) have higher mortality rates than similar patients without CI and may be additionally vulnerable to low staffing. OBJECTIVES: To explore associations between registered nurse (RN) and nursing assistant (NA) staffing levels, mortality and readmission in older patients admitted to general medical/surgical wards. RESEARCH DESIGN: Retrospective cohort. PARTICIPANTS: All unscheduled admissions to an English hospital of people aged ≥75 with cognitive screening over 14 months. MEASURES: The exposure was defined as deviation in staffing hours from the ward daily mean, averaged across the patient stay. Outcomes were mortality in hospital/within 30 days of discharge and 30-day re-admission. Analyses were stratified by CI. RESULTS: 12,544 admissions were included. Patients with CI (33.2%) were exposed to similar levels of staffing as those without. An additional 0.5 RN hours per day was associated with 10% reduction in the odds of death overall (odds ratio 0.90 [95% CI 0.84-0.97]): 15% in patients with CI (OR 0.85 [0.74-0.98]) and 7% in patients without (OR 0.93 [0.85-1.02]). An additional 0.5 NA hours per day was associated with a 15% increase in mortality in patients with no impairment. Readmissions decreased by 6% for an additional 0.5 RN hours in patients with CI. CONCLUSIONS: Although exposure to low staffing was similar, the impact on mortality and readmission for patients with CI was greater. Increased mortality with higher NA staffing in patients without CI needs exploration.

Charge Carrier Transport and Generation via Trap-Mediated Optical Release in Organic Semiconductor Devices.

The impact of intermixed donor-acceptor domains in organic bulk heterojunction (BHJ) solar cells, using low-donor-content devices as model systems, is clarified. At low donor contents, the devices are found to exhibit anomalously high open-circuit voltages independent of the donor-acceptor energetics. These observations can be consistently explained by a theoretical model based on optical release of trapped holes, assuming the donors behave as trap sites in the gap of the acceptor. Our findings provide guidelines for reducing the large open-circuit voltage losses in organic solar cells and avoiding morphology-induced losses in state-of-the-art BHJ solar cells and photodetectors.

Implementing a system for the real-time risk assessment of patients considered for intensive care.

BACKGROUND: Delay in identifying deterioration in hospitalised patients is associated with delayed admission to an intensive care unit (ICU) and poor outcomes. For the HAVEN project (HICF ref.: HICF-R9-524), we have developed a mathematical model that identifies deterioration in hospitalised patients in real time and facilitates the intervention of an ICU outreach team. This paper describes the system that has been designed to implement the model. We have used innovative technologies such as Portable Format for Analytics (PFA) and Open Services Gateway initiative (OSGi) to define the predictive statistical model and implement the system respectively for greater configurability, reliability, and availability. RESULTS: The HAVEN system has been deployed as part of a research project in the Oxford University Hospitals NHS Foundation Trust. The system has so far processed > 164,000 vital signs observations and > 68,000 laboratory results for > 12,500 patients and the algorithm generated score is being evaluated to review patients who are under consideration for transfer to ICU. No clinical decisions are being made based on output from the system. The HAVEN score has been computed using a PFA model for all these patients. The intent is that this score will be displayed on a graphical user interface for clinician review and response. CONCLUSIONS: The system uses a configurable PFA model to compute the HAVEN score which makes the system easily upgradable in terms of enhancing systems' predictive capability. Further system enhancements are planned to handle new data sources and additional management screens.

Melanin Biopolymers: Tailoring Chemical Complexity for Materials Design.

Melanins, a group of dark insoluble pigments found widespread in nature, have become the focus of growing interest in materials science for various biomedical and technological applications, including opto-bioelectronics, nanomedicine and mussel-inspired surface coating. Recent progress in the understanding of melanin optical, paramagnetic redox, and conductivity properties, including photoconductivity, would point to a revision of the traditional concept of structural disorder in terms of more sophisticated and interrelated levels of chemical complexity which however have never been defined and codified. Herein, we bring to focus the various levels of structural disorder that emerged from spectral and chemical signatures over the past decade. A revised approach to structure-property relationships in terms of intermolecular interactions is also provided that may pave the way towards the rational design of next-generation melanin-based functional materials.

Are long nursing shifts on hospital wards associated with sickness absence? A longitudinal retrospective observational study.

OBJECTIVE: To investigate whether working 12 hr shifts is associated with increased sickness absence among registered nurses and health care assistants. BACKGROUND: Previous studies reported negative impacts on nurses' 12 hr shifts; however, these studies used cross-sectional techniques and subjective nurse-reported data. METHODS: A retrospective longitudinal study using routinely collected data across 32 general inpatient wards at an acute hospital in England. We used generalized linear mixed models to explore the association between shift patterns and the subsequent occurrence of short (<7 days) or long-term (≥7 days) sickness absence. RESULTS: We analysed 601,282 shifts and 8,090 distinct episodes of sickness absence. When more than 75% of shifts worked in the past 7 days were 12 hr in length, the odds of both a short-term (adjusted odds ratio = 1.28; 95% confidence index: 1.18-1.39) and long-term sickness episode (adjusted odds ratio = 1.22; 95% confidence index: 1.08-1.37) were increased compared with working none. CONCLUSION: Working long shifts on hospital wards is associated with a higher risk of sickness absence for registered nurses and health care assistants. IMPLICATIONS FOR NURSING MANAGEMENT: The higher sickness absence rates associated with long shifts could result in additional costs or loss of productivity for hospitals. The routine implementation of long shifts should be avoided.

National Early Warning Score Accurately Discriminates the Risk of Serious Adverse Events in Patients With Liver Disease.

BACKGROUND & AIMS: The National Early Warning Score (NEWS) is used to identify deteriorating adult hospital inpatients. However, it includes physiological parameters frequently altered in patients with cirrhosis. We aimed to assess the performance of the NEWS in acute and chronic liver diseases. METHODS: We collected vital signs, recorded in real time, from completed consecutive admissions of patients 16 years or older to a large acute-care hospital in Southern England, from January 1, 2010, through October 31, 2014. Using International Classification of Diseases, 10th revision, codes, we categorized patients as having primary liver disease, secondary liver disease, or none. For patients with liver disease, 2 analysis groups were developed: the first was based on clinical group (such as acute or chronic, alcohol-induced, or associated with portal hypertension), and the second was based on a summary of liver-related, hospital-level mortality indicator diagnoses. For each, we compared the abilities of the NEWS and 34 other early warning scores to discriminate 24-hour mortality, cardiac arrest, or unanticipated admission to the intensive care unit using the area under the receiver operating characteristic (AUROC) curve and early warning score efficiency curve analyses. RESULTS: The NEWS identified patients with primary, nonprimary, and no diagnoses of liver disease with AUROC values of 0.873 (95% CI, 0.860-0.886), 0.898 (95% CI, 0.891-0.905), and 0.879 (95% CI, 0.877-0.881), respectively. High AUROC values were also obtained for all clinical subgroups; the NEWS identified patients with alcohol-related liver disease with an AUROC value of 0.927 (95% CI, 0.912-0.941). The NEWS identified patients with liver diseases with higher AUROC values than other early warning scoring systems. CONCLUSIONS: The NEWS accurately discriminates patients at risk of death, admission to the intensive care unit, or cardiac arrest within a 24-hour period for a range of liver-related diagnoses. Its widespread use provides a ready-made, easy-to-use option for identifying patients with liver disease who require early assessment and intervention, without the need to modify parameters, weightings, or escalation criteria.

A Comparison of the Quick Sequential (Sepsis-Related) Organ Failure Assessment Score and the National Early Warning Score in Non-ICU Patients With/Without Infection.

OBJECTIVES: The Sepsis-3 task force recommended the quick Sequential (Sepsis-Related) Organ Failure Assessment score for identifying patients with suspected infection who are at greater risk of poor outcomes, but many hospitals already use the National Early Warning Score to identify high-risk patients, irrespective of diagnosis. We sought to compare the performance of quick Sequential (Sepsis-Related) Organ Failure Assessment and National Early Warning Score in hospitalized, non-ICU patients with and without an infection. DESIGN: Retrospective cohort study. SETTING: Large U.K. General Hospital. PATIENTS: Adults hospitalized between January 1, 2010, and February 1, 2016. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We applied the quick Sequential (Sepsis-Related) Organ Failure Assessment score and National Early Warning Score to 5,435,344 vital signs sets (241,996 hospital admissions). Patients were categorized as having no infection, primary infection, or secondary infection using International Classification of Diseases, 10th Edition codes. National Early Warning Score was significantly better at discriminating in-hospital mortality, irrespective of infection status (no infection, National Early Warning Score 0.831 [0.825-0.838] vs quick Sequential [Sepsis-Related] Organ Failure Assessment 0.688 [0.680-0.695]; primary infection, National Early Warning Score 0.805 [0.799-0.812] vs quick Sequential [Sepsis-Related] Organ Failure Assessment 0.677 [0.670-0.685]). Similarly, National Early Warning Score performed significantly better in all patient groups (all admissions, emergency medicine admissions, and emergency surgery admissions) for all outcomes studied. Overall, quick Sequential (Sepsis-Related) Organ Failure Assessment performed no better, and often worse, in admissions with infection than without. CONCLUSIONS: The National Early Warning Score outperforms the quick Sequential (Sepsis-Related) Organ Failure Assessment score, irrespective of infection status. These findings suggest that quick Sequential (Sepsis-Related) Organ Failure Assessment should be reevaluated as the system of choice for identifying non-ICU patients with suspected infection who are at greater risk of poor outcome.

Charge Generation Pathways in Organic Solar Cells: Assessing the Contribution from the Electron Acceptor.

Photocurrent generation in organic bulk heterojunction (BHJ) solar cells is most commonly understood as a process which predominantly involves photoexcitation of the lower ionization potential species (donor) followed by electron transfer to the higher electron affinity material (acceptor) [i.e., photoinduced electron transfer (PET), which we term Channel I]. A mirror process also occurs in which photocurrent is generated through photoexcitation of the acceptor followed by hole transfer to the nonexcited donor or photoinduced hole transfer (PHT), which we term Channel II. The role of Channel II photocurrent generation has often been neglected due to overlap of the individual absorption spectra of the donor and acceptor materials that are commonly used. More recently Channel II charge generation has been explored for several reasons. First, many of the new high-efficiency polymeric donors are used as the minority component in bulk heterojunction blends, and therefore, the acceptor absorption is a significant fraction of the total; second, nonfullerene acceptors have been prepared, which through careful design, allow for spectral separation from the donor material, facilitating fundamental studies on charge generation. In this article, we review the methodologies for investigating the two charge generation channels. We also discuss the factors that affect charge generation via Channel I and II pathways, including energy levels of the materials involved, exciton diffusion, and other considerations. Finally, we take a comprehensive look at the nonfullerene acceptor literature and discuss what information about Channel I and Channel II can be obtained from the experiments conducted and what other experiments could be undertaken to provide further information about the operational efficiencies of Channels I and II.

Hospital outcomes of older people with cognitive impairment: An integrative review.

OBJECTIVES: To summarise existing knowledge of outcomes of older hospital patients with cognitive impairment, including the type and frequency of outcomes reported, and the additional risk experienced by this patient group. METHODS: Integrative literature review. Health care literature databases, reports, and policy documents on key websites were systematically searched. Papers describing the outcomes of older people with cognitive impairment during hospitalisation and at discharge were analysed and summarised using integrative methods. RESULTS: One hundred four articles were included. A range of outcomes were identified, including those occurring during hospitalisation and at discharge. Older people with a dementia diagnosis were at higher risk from death in hospital, nursing home admission, long lengths of stay, as well as intermediate outcomes such as delirium, falls, dehydration, reduction in nutritional status, decline in physical and cognitive function, and new infections in hospital. Fewer studies examined the relationship of all-cause cognitive impairment with outcomes. Patient and carer experiences of hospital admission were often poor. Few studies collected data relating to hospital environment, eg, ward type or staffing levels, and acuity of illness was rarely described. CONCLUSIONS: Older people with cognitive impairment have a higher risk of a variety of negative outcomes in hospital. Prevalent intermediate outcomes suggest that changes in care processes are required to ensure maintenance of fundamental care provision and greater attention to patient safety in this vulnerable group. More research is required to understand the most appropriate ways of doing this and how changes in these care processes are best implemented to improve hospital outcomes.

The association between nurse staffing and omissions in nursing care: A systematic review.

AIMS: To identify nursing care most frequently missed in acute adult inpatient wards and to determine evidence for the association of missed care with nurse staffing. BACKGROUND: Research has established associations between nurse staffing levels and adverse patient outcomes including in-hospital mortality. However, the causal nature of this relationship is uncertain and omissions of nursing care (referred as missed care, care left undone or rationed care) have been proposed as a factor which may provide a more direct indicator of nurse staffing adequacy. DESIGN: Systematic review. DATA SOURCES: We searched the Cochrane Library, CINAHL, Embase and Medline for quantitative studies of associations between staffing and missed care. We searched key journals, personal libraries and reference lists of articles. REVIEW METHODS: Two reviewers independently selected studies. Quality appraisal was based on the National Institute for Health and Care Excellence quality appraisal checklist for studies reporting correlations and associations. Data were abstracted on study design, missed care prevalence and measures of association. Synthesis was narrative. RESULTS: Eighteen studies gave subjective reports of missed care. Seventy-five per cent or more nurses reported omitting some care. Fourteen studies found low nurse staffing levels were significantly associated with higher reports of missed care. There was little evidence that adding support workers to the team reduced missed care. CONCLUSIONS: Low Registered Nurse staffing is associated with reports of missed nursing care in hospitals. Missed care is a promising indicator of nurse staffing adequacy. The extent to which the relationships observed represent actual failures, is yet to be investigated.

What impact does nursing care left undone have on patient outcomes? Review of the literature.

AIMS AND OBJECTIVES: Systematic review of the impact of missed nursing care on outcomes in adults, on acute hospital wards and in nursing homes. BACKGROUND: A considerable body of evidence supports the hypothesis that lower levels of registered nurses on duty increase the likelihood of patients dying on hospital wards, and the risk of many aspects of care being either delayed or left undone (missed). However, the direct consequence of missed care remains unclear. DESIGN: Systematic review. METHODS: We searched Medline (via Ovid), CINAHL (EBSCOhost) and Scopus for studies examining the association of missed nursing care and at least one patient outcome. Studies regarding registered nurses, healthcare assistants/support workers/nurses' aides were retained. Only adult settings were included. Because of the nature of the review, qualitative studies, editorials, letters and commentaries were excluded. PRISMA guidelines were followed in reporting the review. RESULTS: Fourteen studies reported associations between missed care and patient outcomes. Some studies were secondary analyses of a large parent study. Most of the studies used nurse or patient reports to capture outcomes, with some using administrative data. Four studies found significantly decreased patient satisfaction associated with missed care. Seven studies reported associations with one or more patient outcomes including medication errors, urinary tract infections, patient falls, pressure ulcers, critical incidents, quality of care and patient readmissions. Three studies investigated whether there was a link between missed care and mortality and from these results no clear associations emerged. CONCLUSIONS: The review shows the modest evidence base of studies exploring missed care and patient outcomes generated mostly from nurse and patient self-reported data. To support the assertion that nurse staffing levels and skill mix are associated with adverse outcomes as a result of missed care, more research that uses objective staffing and outcome measures is required. RELEVANCE TO CLINICAL PRACTICE: Although nurses may exercise judgements in rationing care in the face of pressure, there are nonetheless adverse consequences for patients (ranging from poor experience of care to increased risk of infection, readmissions and complications due to critical incidents from undetected physiological deterioration). Hospitals should pay attention to nurses' reports of missed care and consider routine monitoring as a quality and safety indicator.

Universal screening for alcohol misuse in acute medical admissions is feasible and identifies patients at high risk of liver disease.

BACKGROUND & AIMS: Many people who die from alcohol related liver disease (ARLD) have a history of recurrent admissions to hospital, representing potential missed opportunities for intervention. Universal screening for alcohol misuse has been advocated but it is not known if this is achievable or effective at detecting individuals at high risk of ARLD. METHODS: We systematically screened all admissions to the Acute Medical Unit (AMU) of a large acute hospital using an electronic data capture system in real time. Patients at an increasing risk of alcohol harm were referred for either brief intervention (BI) or further assessment by an Alcohol Specialist Nursing Service (ASNS). Additional data were recorded on admission diagnoses, alcohol unit consumption, previous attendances, previous admissions, length of stay and mortality. RESULTS: Between July 2011 and March 2014, there were 53,165 admissions and 48,211 (90.68%) completed screening. Of these, 1,122 (2.3%) were classified as "increasing", and 1,921 (4.0%) as "high" risk of alcohol harm. High risk patients had more hospital admissions in the three previous years (average 4.74) than the low (3.00) and increasing (2.92) risk groups (p<0.001). The high risk patients also had more frequent emergency department (ED) attendances (7.68) than the lower (2.64) and increasing (3.81) groups (p<0.001 for both). A total of 1,396 (72.6%) of the high risk group were seen by the ASNS and 1,135 (81.2%) had an Alcohol Use Disorders Identification Test (AUDIT) score over 20 with 527 (37.8%) recording the maximum value of 40. Compared to the other groups, high risk patients had a distinct profile of admissions with the most common diagnoses being mental health disorders, gastro-intestinal bleeding, poisoning and liver disease. CONCLUSIONS: Universal screening of admissions for alcohol misuse is feasible and identifies a cohort with frequent ED attendances, recurrent admissions and an elevated risk of ARLD. An additional group of patients at an increasing risk of alcohol harm can be identified in a range of common presentations. These patients can be targeted with interventions to reduce the burden of alcohol related harm. Lay summary: Many people who die from alcohol related liver disease (ARLD) have a recent history of recurrent admissions to hospital. These admissions may represent missed opportunities to intervene earlier and offer effective therapies for alcohol misuse. Unfortunately, we know that patients are often missed because medical staff may not routinely ask about alcohol consumption. In our study of over 50,000 admissions, we have demonstrated the feasibility of offering screening for alcohol misuse to all medical admissions to hospital and delivered this 24hours a day, 7days a week, with automatic referral to treatment services. We have shown that it is possible to identify those people who are at the highest risk of dependency, those who have attended the emergency department the most and those who are at an increased risk of ARLD. We hope this study will lead to improved detection and management of alcohol problems in acute hospitals.

Organohalide Perovskites for Solar Energy Conversion.

Lead-based organohalide perovskites have recently emerged as arguably the most promising of all next generation thin film solar cell technologies. Power conversion efficiencies have reached 20% in less than 5 years, and their application to other optoelectronic device platforms such as photodetectors and light emitting diodes is being increasingly reported. Organohalide perovskites can be solution processed or evaporated at low temperatures to form simple thin film photojunctions, thus delivering the potential for the holy grail of high efficiency, low embedded energy, and low cost photovoltaics. The initial device-driven "perovskite fever" has more recently given way to efforts to better understand how these materials work in solar cells, and deeper elucidation of their structure-property relationships. In this Account, we focus on this element of organohalide perovskite chemistry and physics in particular examining critical electro-optical, morphological, and architectural phenomena. We first examine basic crystal and chemical structure, and how this impacts important solar-cell related properties such as the optical gap. We then turn to deeper electronic phenomena such as carrier mobilities, trap densities, and recombination dynamics, as well as examining ionic and dielectric properties and how these two types of physics impact each other. The issue of whether organohalide perovskites are predominantly nonexcitonic at room temperature is currently a matter of some debate, and we summarize the evidence for what appears to be the emerging field consensus: an exciton binding energy of order 10 meV. Having discussed the important basic chemistry and physics we turn to more device-related considerations including processing, morphology, architecture, thin film electro-optics and interfacial energetics. These phenomena directly impact solar cell performance parameters such as open circuit voltage, short circuit current density, internal and external quantum efficiency, fill factor, and ultimately the all-important power conversion efficiency. Finally, we address the key challenges pertinent to actually delivering a new and viable solar cell technology. These include long-term cell stability, scaling to the module level, and the toxicity associated with lead. Organohalide perovskites not only offer exciting possibilities for next generation optoelectronics and photovoltaics, but are an intriguing class of material crossing the boundaries of molecular solids and banded inorganic semiconductors. This is a potential area of rich new chemistry, materials science, and physics.

The structural impact of water sorption on device-quality melanin thin films.

The melanins are a class of pigmentary bio-macromolecules ubiquitous in the biosphere. They possess an intriguing set of physico-chemical properties and have been shown to exhibit hybrid protonic-electronic electrical conductivity, a feature derived from a process termed chemical self-doping driven by the sorption of water. Although the mechanism underlying the electrical conduction has been established, how the sorbed water interacts with the melanin structure at the physical level has not. Herein we use neutron reflectometry to study changes in the structure of synthetic melanin thin films as a function of H2O and D2O vapour pressure. Water is found to be taken up evenly throughout the films, and by employing the contrast effect, the existence of labile protons through reversible deuterium exchange is demonstrated. Finally, we determine a sorption isotherm to enable quantification of the melanin-water interactions.

The relationship between cognitive impairment, mortality and discharge characteristics in a large cohort of older adults with unscheduled admissions to an acute hospital: a retrospective observational study.

Background: older people with dementia admitted to hospital for acute illness have higher mortality and longer hospital stays compared to those without dementia. Cognitive impairment (CI) is common in older people, and they may also be at increased risk of poor outcomes. Methods: retrospective observational study of unscheduled admissions aged ≥75 years. Admission characteristics, mortality rates and discharge outcomes were compared between three groups: (i) known dementia diagnosis (DD), (ii) CI but no diagnosis of dementia and (iii) no CI. Results: of 19,269 admissions (13,652 patients), 19.8% had a DD, 11.6% had CI and 68.6% had neither. Admissions with CI or DD were older and had more females than those with no CI, and were more likely to be admitted through the Emergency Department (88.4% and 90.7%, versus 82.0%) and to medical wards (89.4% and 84.4%, versus 76.8%). Acuity levels at admission were similar between the groups. Patients with CI or DD had more admissions at 'high risk' from malnutrition than patients with no CI (28.0% and 33.7% versus 17.5%), and a higher risk of dying in hospital (11.8% [10.5-13.3] and 10.8% [9.8-11.9] versus (6.6% [6.2-7.0])). Conclusions: the admission characteristics, mortality and length of stay of patients with CI resemble those of patients with diagnosed dementia. Whilst attention has been focussed on the need for additional support for people with dementia, patients with CI, which may include those with undiagnosed dementia or delirium, appear to have equally bad outcomes from hospitalisation.