Effect of Plasma Treatment on Metal Oxide p–n Thin Film Diodes Fabricated at Room Temperature

Funder: Cambridge Trust; Id: http://dx.doi.org/10.13039/501100003343Abstract: There is a need for a good quality thin film diode using a metal oxide p–n heterojunction as it is an essential component for the realization of flexible large‐area electronics. However, metal oxide‐based diodes normally show poor rectification characteristics whose origin is still poorly understood; this is holding back their use in various applications. A systematic study of the origins of the poor performance is performed based on bias‐stress measurements using a cuprous oxide (Cu2O)/amorphous zinc‐tin oxide (a‐ZTO) heterojunction as an example. This suggests that multiple carrier trapping and thermal release of carriers in defect states stemming from oxygen vacancies at the heterojunction interface is the primary cause of poor rectification. It is demonstrated that a plasma treatment is an effective way to optimize the population of oxygen vacancies at the heterojunction interface based on extensive material analyses, allowing a significant improvement in the diode performance with a much‐enhanced rectification ratio from ≈20 to 10 000, and a consequent facilitation of the next‐generation of ubiquitous electronics

Are agriculture and nutrition policies and practice coherent? Stakeholder evidence from Afghanistan

Despite recent improvements in the national average, stunting levels in Afghanistan exceed 70% in some Provinces. Agriculture serves as the main source of livelihood for over half of the population and has the potential to be a strong driver of a reduction in under-nutrition. This article reports research conducted through interviews with stakeholders in agriculture and nutrition in the capital, Kabul, and four provinces of Afghanistan, to gain a better understanding of the institutional and political factors surrounding policy making and the nutrition-sensitivity of agriculture. Semi-structured interviews were conducted with a total of 46 stakeholders from central government and four provinces, including staff from international organizations, NGOs and universities. We found evidence of interdisciplinary communication at the central level and within Provinces, but little evidence of vertical coordination in policy formulation and implementation between the centre and Provinces. Policy formulation and decision making were largely sectoral, top-down, and poorly contextualised. The weaknesses identified in policy formulation, focus, knowledge management, and human and financial resources inhibit the orientation of national agricultural development strategies towards nutrition-sensitivity. Integrating agriculture and nutrition policies requires explicit leadership from the centre. However, effectiveness of a food-based approach to reducing nutrition insecurity will depend on decentralising policy ownership to the regions and provinces through stronger subnational governance. Security and humanitarian considerations point to the need to manage and integrate in a deliberate way the acute humanitarian care and long-term development needs, of which malnutrition is just one element

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

Introduction: The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures. Methods: In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025. Findings: Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2–6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5–5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4–10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32–4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23–11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation. Interpretation: After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification

RF Ohmic MEMS Switches Utilizing Printed and Carbon Based Nanomaterials for Space Applications

This thesis is devoted to the development of Radio Frequency (RF) Ohmic (metal-to-metal contact-type) MEMS (micro-electro-mechanical-systems) Switches for Space Applications. Ohmic contact devices void of any dielectric layer are considered exclusively in order to avoid the possibility of dielectric charging during operation, which is a possible failure mode. Cantilevered topologies are solely considered, and all devices are tested unpackaged with a gentle flow of nitrogen gas in standard laboratory conditions. Both DC and RF devices are considered, explored and developed that are each insensitive to stress and temperature effects while utilizing relatively simplistic surface micromachined fabrication processes consisting of no more than six mask steps, developed specifically for this work. For the differing processes, a minimum of three and a maximum of six materials are used for device fabrication. The overall motivation is to realize high-reliability and high-power handling ohmic MEMS switches that are compatible with conventional packaging techniques. With these objectives, both Ni and Au are explored for use as a structural MEMS material while controlling the intrinsic stress of both. Devices consisting of dual contact points utilizing differing contact materials are also explored in order to limit hot-switching damage on the ohmic contacts. Analytically, it is shown that the implementation of a refractory metal (Pt) protection contact would extend the switching lifetime of the device. This was also experimentally verified whereby the dual contact device achieved 6 x 10^6 switching cycles under 10V/10mA switching conditions, compared to only 1 x 10^5 switching cycles for an all Au contact interface device of the same structural design under the same switching conditions. The resistance of the designed dual contact DC MEMS switch is found to be approximately 1.5 Ohms at a biasing voltage of 65 V. In addition, considerations for an efficient RF MEMS switch are implemented to produce devices capable of switching from DC up to 40 GHz while also exploring the utilization of carbon nanotubes (CNTs) as a carbon-based nanocomposite contact material. The experimental validation of an ohmic (metal-to-metal) RF Au-Ru contact interface switch with high reliability and power handling (> 10 x 10^6 cycles at 2 W at 25 degrees Celsius) is presented for DC up to 25 GHz applications, where the device isolation and insertion loss is > -20dB and -25dB and < -2dB in terms of RF isolation and insertion loss at a frequency of 10 GHz, respectively. Compared to Au-Au contact device of the same design, the Au-Au/CNT device shows higher switching lifetimes (12 x 10^6 for the Au-Au/CNT device versus 80 x 10^3 for the Au-Au device, under the same test conditions) and less stiction when releasing at elevated temperatures. Raman spectral analysis for the CNT layer post deposition, post fabrication and post lifetime cycling are analysed and compared, showing little change. Finally, further optimization of device arrangement while utilizing dual or multiple contact devices are presented through the use of switching networks in order to extend the hot-switching lifetime of RF MEMS switches while simultaneously improving the on-state device isolation.European Space Agency - ES

Effect of Plasma Treatment on Metal Oxide p–n Thin Film Diodes Fabricated at Room Temperature

Funder: Cambridge Trust; Id: http://dx.doi.org/10.13039/501100003343Abstract: There is a need for a good quality thin film diode using a metal oxide p–n heterojunction as it is an essential component for the realization of flexible large‐area electronics. However, metal oxide‐based diodes normally show poor rectification characteristics whose origin is still poorly understood; this is holding back their use in various applications. A systematic study of the origins of the poor performance is performed based on bias‐stress measurements using a cuprous oxide (Cu2O)/amorphous zinc‐tin oxide (a‐ZTO) heterojunction as an example. This suggests that multiple carrier trapping and thermal release of carriers in defect states stemming from oxygen vacancies at the heterojunction interface is the primary cause of poor rectification. It is demonstrated that a plasma treatment is an effective way to optimize the population of oxygen vacancies at the heterojunction interface based on extensive material analyses, allowing a significant improvement in the diode performance with a much‐enhanced rectification ratio from ≈20 to 10 000, and a consequent facilitation of the next‐generation of ubiquitous electronics

Seismic risk management: A system-based perspective

Seismic risk analysis is fraught with complexity, ambiguity and uncertainty which pose critical challenges in assessing, modeling and management. Emergent complexity of earthquake impacts and uncertain nature of information commonly involved in assessment process necessitate establishing a risk management system to address the risk in a reliable and realistic way. The study was launched to review and discuss appropriate risk assessment methods for different seismic applications. The characteristics of different risk assessment methods were compared focusing on systemic challenges of analysis including complexity and uncertainty. Different alternatives of modeling systems are proposed, compared and discussed according to their operational appropriateness with the focus on systemic challenges of analysis including complexity and uncertainty. Nevertheless, selection of specific risk assessment approach requires in-depth understanding of the multidimensional aspects of risk, scope and objective of problem, availability of data and type of input-output involved with decision-making process

The Income Inequality Hypothesis Revisited: Assessing the Hypothesis Using Four Methodological Approaches

The income inequality hypothesis states that income inequality has a negative effect on individual’s health, partially because it reduces social trust. This article aims to critically assess the income inequality hypothesis by comparing several analytical strategies, namely OLS regression, multilevel regression, fixed effects models and fixed effects models using pseudo panel data. To test the hypothesis, data from two studies conducted between 1981 and 2014 were combined: the World Values Survey and the European Values Study. Three frequently used measures of health were taken into account. In the OLS and multilevel models, income inequality was often associated with better health, whereas in the fixed effects and pseudo panel data, income inequality was associated with poorer health, suggesting that the unexpected results of the OLS and multilevel methods might be explained by unobserved confounders. Furthermore, in almost all of the models, social trust mediates the relationship between income inequality and health, showing the importance of this mechanism. Interestingly, the pseudo panel data offer the strongest support for the income inequality hypothesis, suggesting that better controlling for confounding factors and/or more carefully monitoring cohort effects, may result in a better understanding whether and how income inequality can be harmful for people’s health

Intraoperative transfusion practices in Europe

Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger- mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)- based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (sd)] just before transfusion was 8.1 (1.7) g dl and increased to 9.8 (1.8) g dl after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Intraoperative transfusion practices and perioperative outcome in the European elderly: A secondary analysis of the observational ETPOS study

The demographic development suggests a dramatic growth in the number of elderly patients undergoing surgery in Europe. Most red blood cell transfusions (RBCT) are administered to older people, but little is known about perioperative transfusion practices in this population. In this secondary analysis of the prospective observational multicentre European Transfusion Practice and Outcome Study (ETPOS), we specifically evaluated intraoperative transfusion practices and the related outcomes of 3149 patients aged 65 years and older. Enrolled patients underwent elective surgery in 123 European hospitals, received at least one RBCT intraoperatively and were followed up for 30 days maximum. The mean haemoglobin value at the beginning of surgery was 108 (21) g/l, 84 (15) g/l before transfusion and 101 (16) g/l at the end of surgery. A median of 2 [1–2] units of RBCT were administered. Mostly, more than one transfusion trigger was present, with physiological triggers being preeminent. We revealed a descriptive association between each intraoperatively administered RBCT and mortality and discharge respectively, within the first 10 postoperative days but not thereafter. In our unadjusted model the hazard ratio (HR) for mortality was 1.11 (95% CI: 1.08–1.15) and the HR for discharge was 0.78 (95% CI: 0.74–0.83). After adjustment for several variables, such as age, preoperative haemoglobin and blood loss, the HR for mortality was 1.10 (95% CI: 1.05–1.15) and HR for discharge was 0.82 (95% CI: 0.78–0.87). Preoperative anaemia in European elderly surgical patients is undertreated. Various triggers seem to support the decision for RBCT. A closer monitoring of elderly patients receiving intraoperative RBCT for the first 10 postoperative days might be justifiable. Further research on the causal relationship between RBCT and outcomes and on optimal transfusion strategies in the elderly population is warranted. A thorough analysis of different time periods within the first 30 postoperative days is recommended

Cognitive and psychiatric symptom trajectories 2–3 years after hospital admission for COVID-19: a longitudinal, prospective cohort study in the UK

Background: COVID-19 is known to be associated with increased risks of cognitive and psychiatric outcomes after the acute phase of disease. We aimed to assess whether these symptoms can emerge or persist more than 1 year after hospitalisation for COVID-19, to identify which early aspects of COVID-19 illness predict longer-term symptoms, and to establish how these symptoms relate to occupational functioning. Methods: The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study of adults (aged ≥18 years) who were hospitalised with a clinical diagnosis of COVID-19 at participating National Health Service hospitals across the UK. In the C-Fog study, a subset of PHOSP-COVID participants who consented to be recontacted for other research were invited to complete a computerised cognitive assessment and clinical scales between 2 years and 3 years after hospital admission. Participants completed eight cognitive tasks, covering eight cognitive domains, from the Cognitron battery, in addition to the 9-item Patient Health Questionnaire for depression, the Generalised Anxiety Disorder 7-item scale, the Functional Assessment of Chronic Illness Therapy Fatigue Scale, and the 20-item Cognitive Change Index (CCI-20) questionnaire to assess subjective cognitive decline. We evaluated how the absolute risks of symptoms evolved between follow-ups at 6 months, 12 months, and 2–3 years, and whether symptoms at 2–3 years were predicted by earlier aspects of COVID-19 illness. Participants completed an occupation change questionnaire to establish whether their occupation or working status had changed and, if so, why. We assessed which symptoms at 2–3 years were associated with occupation change. People with lived experience were involved in the study. Findings: 2469 PHOSP-COVID participants were invited to participate in the C-Fog study, and 475 participants (191 [40·2%] females and 284 [59·8%] males; mean age 58·26 [SD 11·13] years) who were discharged from one of 83 hospitals provided data at the 2–3-year follow-up. Participants had worse cognitive scores than would be expected on the basis of their sociodemographic characteristics across all cognitive domains tested (average score 0·71 SD below the mean [IQR 0·16–1·04]; p<0·0001). Most participants reported at least mild depression (263 [74·5%] of 353), anxiety (189 [53·5%] of 353), fatigue (220 [62·3%] of 353), or subjective cognitive decline (184 [52·1%] of 353), and more than a fifth reported severe depression (79 [22·4%] of 353), fatigue (87 [24·6%] of 353), or subjective cognitive decline (88 [24·9%] of 353). Depression, anxiety, and fatigue were worse at 2–3 years than at 6 months or 12 months, with evidence of both worsening of existing symptoms and emergence of new symptoms. Symptoms at 2–3 years were not predicted by the severity of acute COVID-19 illness, but were strongly predicted by the degree of recovery at 6 months (explaining 35·0–48·8% of the variance in anxiety, depression, fatigue, and subjective cognitive decline); by a biocognitive profile linking acutely raised D-dimer relative to C-reactive protein with subjective cognitive deficits at 6 months (explaining 7·0–17·2% of the variance in anxiety, depression, fatigue, and subjective cognitive decline); and by anxiety, depression, fatigue, and subjective cognitive deficit at 6 months. Objective cognitive deficits at 2–3 years were not predicted by any of the factors tested, except for cognitive deficits at 6 months, explaining 10·6% of their variance. 95 of 353 participants (26·9% [95% CI 22·6–31·8]) reported occupational change, with poor health being the most common reason for this change. Occupation change was strongly and specifically associated with objective cognitive deficits (odds ratio [OR] 1·51 [95% CI 1·04–2·22] for every SD decrease in overall cognitive score) and subjective cognitive decline (OR 1·54 [1·21–1·98] for every point increase in CCI-20). Interpretation: Psychiatric and cognitive symptoms appear to increase over the first 2–3 years post-hospitalisation due to both worsening of symptoms already present at 6 months and emergence of new symptoms. New symptoms occur mostly in people with other symptoms already present at 6 months. Early identification and management of symptoms might therefore be an effective strategy to prevent later onset of a complex syndrome. Occupation change is common and associated mainly with objective and subjective cognitive deficits. Interventions to promote cognitive recovery or to prevent cognitive decline are therefore needed to limit the functional and economic impacts of COVID-19. Funding: National Institute for Health and Care Research Oxford Health Biomedical Research Centre, Wolfson Foundation, MQ Mental Health Research, MRC-UK Research and Innovation, and National Institute for Health and Care Research.</p