Halide perovskites: Current issues and new strategies to push material and device stability

Abstract This short review aims at summarizing the current challenges related to poor Perovskite Solar Cells (PSCs) stability which nowadays puts severe constrains on near future device commercialization. As a game changer in the field of photovoltaics (PVs), PSCs are highly efficient and cheap to fabricate. However, they suffer from poor long-term stability upon exposure to heat, moisture, oxygen and light, and combinations thereof. Poor device stability originates from intrinsic instability issues of the perovskite active layer itself, as well as extrinsic factors due to partial degradation of the layers composing the device stack. Here we briefly review the chemical and physical processes responsible for intrinsic material instability, and we highlight possible solutions to overcome it; we then consider the whole device, discussing properties and interactions of the stacked layers. Finally, particular emphasis is placed on the need of shared standards for stability tests, which should include detailed report on experimental conditions over a statistically significant number of samples, allowing for a direct comparison of results across different groups and fostering a rapid advance of our understanding of degradation mechanisms and of the solutions to overcome them

RUOLO CENTRALE DELLA BETA-CELLULA NEL PROMUOVERE LA REGRESSIONE DEL DIABETE DOPO TRAPIANTO DI FEGATO IN PAZIENTI CON CIRROSI EPATICA

BACKGROUND & AIMS: Diabetes occurring as a direct consequence of loss of liver function is usually characterized by non-diabetic fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c) levels and should regress after orthotopic liver transplantation (OLT). This observational, longitudinal study investigated the relationship between the time-courses of changes in all 3 direct determinants of glucose regulation, i.e., \u3b2-cell function, insulin clearance and insulin sensitivity, and diabetes regression after OLT. METHODS: Eighty cirrhotic patients with non-diabetic FPG and HbA1c levels underwent an extended oral glucose tolerance test (OGTT) before and 3, 6, 12 and 24\u202fmonths after OLT. The OGTT data were analysed with a mathematical model to estimate derivative control (DC) and proportional control (PC) of \u3b2-cell function and insulin clearance (which determine insulin bioavailability), and with the Oral Glucose Insulin Sensitivity (OGIS)-2\u202fh index to estimate insulin sensitivity. RESULTS: At baseline, 36 patients were diabetic (45%) and 44 were non-diabetic (55%). Over the 2-year follow-up, 23 diabetic patients (63.9%) regressed to non-diabetic glucose regulation, whereas 13 did not (36.1%); moreover, 4 non-diabetic individuals progressed to diabetes (9.1%), whereas 40 did not (90.9%). Both DC and PC increased in regressors (from month 3 and 24, respectively) and decreased in progressors, whereas they remained stable in non-regressors and only PC decreased in non-progressors. Insulin clearance increased in all groups, apart from progressors. Likewise, OGIS-2\u202fh improved at month 3 in all groups, but thereafter it continued to improve only in regressors, whereas it returned to baseline values in the other groups. CONCLUSIONS: Increased insulin bioavailability driven by improved \u3b2-cell function plays a central role in favouring diabetes regression after OLT, in the presence of a sustained improvement of insulin sensitivity

Initial validation of an agile coupled atmosphere-ocean general circulation model

Mathematical models based on physics, chemistry and biology principles are one of the main tools to understand climate interactions, variability and sensitivity to forcings. Model performance must be validated checking that results are consistent with actual/observed climate. This work describes the initial validation of a new intermediate complexity, coupled climate model based on a set of existing atmosphere, ocean and sea-ice models. The model, developed and made available by the International Centre for Theoretical Physics (ICTP), is based on the widely used SPEEDY atmospheric model. Limited literature is available for its version, coupled to the NEMO ocean model referred to as SPEEDY-NEMO. The focus of this study is on the adaptation and validation of this model. A long-term spin-up run with constant present-day forcing has been performed to achieve a steady-state climate. The simulated climate has then been compared with observations and reanalyses of the recent past. The initial validation has shown that simulations spanning a thousand years can be easily run. The model does not require many h/w resources and therefore significant size samples can be generated if needed. Our results prove that long timescale, stable simulations are feasible. The model reproduces the main features of Earth’s mean climate and variability, despite the use of a fairly limited resolution grid, simple parameterizations and a limited range of physical processes. Ocean model outputs have not been assessed. However, a clear El Niño signal in the simulated Sea Surface Temperatures (SSTs) data and arctic sea ice extent show that the ocean model behaviour is close to observations. According to the results, the model is a promising tool for climate studies. However, to understand its full potential the validation should be improved and extended with an analysis of ocean variables and targeted simulations with modified conditions to evaluate model behaviour under different condition

All-Inorganic Cesium-Based Hybrid Perovskites for Efficient and Stable Solar Cells and Modules

AbstractIn the last ten years, organic–inorganic hybrid perovskites have been skyrocketing the field of innovative photovoltaics (PVs) and now represent one of the most promising solution for next‐generation PVs. Within the family of halide perovskites, increasing attention has been focused on the so‐called all‐inorganic group, where the organic cation is replaced by cesium, as in the case of CsPbI3. This subclass of halide perovskites features desirable optoelectronic properties such as easily tunable bandgap, strong defect tolerance, and improved thermal stability compared to the hybrid systems. When integrated in PV cells, they exhibit high power conversion efficiency (PCE) with record values of 19.03%. However, all‐inorganic perovskite solar cells (PCSs) face several challenges such as i) instability of the CsPbI3 photoactive phase in ambient conditions, ii) inhomogeneous film morphology, and iii) high surface defect density. This work focuses on the mentioned challenges with a special attention on discussing the Cs–Pb–X system (X = I, Br). Then, the most recent and effective approaches for increasing both the PCE and the stability of devices are reviewed, which include material doping, interface engineering, and device optimization. Finally, the first efforts toward the upscaling of Cs‐based PSCs, and predicted methods for enabling large‐scale production, are discussed

Impaired glucose metabolism in subjects with the Williams-Beuren syndrome. A five-year follow-up cohort study

Objective. The Williams-Beuren syndrome (WS) is associated with impaired glucose metabolism (IGM) early in adulthood. However, the pathophysiology of IGM remains poorly defined, due to the lack longitudinal studies investigating the contribution of β-cell dysfunction and impaired insulin sensitivity. This study aimed at assessing incidence of IGM and the underlying mechanisms in WS adults. Methods. This observational, longitudinal (5-year), cohort study enrolled thirty-one consecutive WS subjects attending a tertiary referral center. An oral glucose tolerance test (OGTT) was performed yearly and used to classify patients as normal or IGM, including impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and diabetes mellitus (DM), and to calculate surrogate measures of insulin secretion and/or sensitivity. Results. IGM patients were 18 (58.1%, three DM) at baseline and 19 (61.3%, five DM) at end-of-follow-up. However, 13 individuals changed category of glucose homeostasis in both directions during follow-up (8 progressors, 5 regressors) and 18 did not (8 non-progressors, 10 non-regressors). New cases of IGM and DM were 11.1 and 2.53 per 100 persons-year, respectively, and were treated non-pharmacologically. In the whole cohort and, to a higher extent, in progressors, indices of early-phase insulin secretion and insulin sensitivity decreased significantly from baseline to end-of-follow-up, with concurrent reduction of the oral disposition index and insulin secretion-sensitivity index-2 (ISSI-2), compensating insulin secretion for the level of insulin resistance. No baseline measure independently predicted progression, which correlated with change from baseline in ISSI-2. Compared with patients with normal glucose homeostasis, IGT subjects had impaired insulin sensitivity, whereas insulin secretion was reduced only in those with IFG+IGT or DM. Conclusions. IGM incidence is high in young adults with WS, suggesting the need of early screening and timed intervention. As in classical type 2 diabetes, impaired insulin sensitivity and β-cell dysfunction contribute, in this sequence, to progression to IGM and DM

Jesús RUBIO JIMÉNEZ, "La herencia de Antonio Machado (1939-1970)", Zaragoza, Prensas universitarias, 2018, 350 pp.

Jesús RUBIO JIMÉNEZ, La herencia de Antonio Machado (1939-1970), Zaragoza, Prensas universitarias, 2018, 350 pp.Jesús RUBIO JIMÉNEZ, La herencia de Antonio Machado (1939-1970), Zaragoza, Prensas universitarias, 2018, 350 pp

Jesús RUBIO JIMÉNEZ, "La herencia de Antonio Machado (1939-1970)", Zaragoza, Prensas universitarias, 2018, 350 pp.

Jesús RUBIO JIMÉNEZ, La herencia de Antonio Machado (1939-1970), Zaragoza, Prensas universitarias, 2018, 350 pp.Jesús RUBIO JIMÉNEZ, La herencia de Antonio Machado (1939-1970), Zaragoza, Prensas universitarias, 2018, 350 pp

Risk Aversion and Fiscal Consolidation Programs

In this paper we provide evidence that there are statistical and economically meaningful differences in terms of attitudes towards risk at the aggregate level across countries, as captured by country-specific estimations of the coefficient of relative risk aversion. This has important implications for fiscal policy as it leads to large differences in the output response to the same fiscal policy shock. When calibrating the risk aversion at the country level, using country-specific estimates of the coefficient of relative risk aversion, we find multipliers to the same fiscal consolidation shock to differ as much as between 0.35 and 0.55

Femtosecond to nanosecond excited states dynamics of novel Corroles

We report a comprehensive photphysical investigation of some corrole molecules employing fs/nanosecond (ns) transient-absorption and time-resolved photoluminescence spectroscopy with support from the time-dependent density-functional theory calculations to understand their intramolecular charge transfer and polaron-absorption character

Cognitive Behavioural Therapy with Exposure and Response Prevention in the treatment of Obsessive-Compulsive Disorder: A systematic review and meta-analysis of randomised controlled trials

© 2021 Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Background: Cognitive behavioural therapy (CBT), incorporating exposure and response prevention (ERP) is widely recognised as the psychological treatment of choice for obsessive-compulsive disorder (OCD). Uncertainty remains however about the magnitude of the effect of CBT with ERP and the impact of moderating factors in patients with OCD. Method: This systematic review and meta-analysis assessed randomised-controlled trials of CBT with ERP in patients of all ages with OCD. The study was preregistered in PROSPERO (CRD42019122311). The primary outcome was end-of-trial OCD symptom scores. The moderating effects of patient-related and study-related factors including type of control intervention and risk of bias were examined. Additional exploratory analyses assessed the effects of treatment fidelity and impact of researcher allegiance. Results: Thirty-six studies were included, involving 2020 patients (537 children/adolescents and 1483 adults) with 1005 assigned to CBT with ERP and 1015 to control conditions. When compared against all control conditions, a large pooled effect size (ES) emerged in favour of CBT with ERP (g = 0.74: 95% CI = 0.51 to 0.97 k = 36), which appeared to diminish with increasing age. While CBT with ERP was more effective than psychological placebo (g = 1.13 95% CI 0.71 to 1.55, k = 10), it was no more effective than other active forms of psychological therapy (g = −0.05: 95% CI -0.27 to 0.16, k = 8). Similarly, whereas CBT with ERP was significantly superior when compared to all forms of pharmacological treatment (g = 0.36: 95% CI 0.7 to 0.64, k = 7), the effect became marginal when compared with adequate dosages of pharmacotherapy for OCD (g = 0.32: 95% CI -0.00 to 0.64, k = 6).A minority of studies (k = 8) were deemed to be at low risk of bias. Moreover, three quarters of studies (k = 28) demonstrated suspected researcher allegiance and these studies reported a large ES (g = 0.95: 95% CI 0.69 to 1.2), while those without suspected researcher allegiance (k = 8) indicated that CBT with ERP was not efficacious (g = 0.02: 95% CI -0.29 to 0.33). Conclusions: A large effect size was found for CBT with ERP in reducing the symptoms of OCD, but depends upon the choice of comparator control. This meta-analysis also highlights concerns about the methodological rigor and reporting of published studies of CBT with ERP in OCD. In particular, efficacy was strongly linked to researcher allegiance and this requires further future investigation.Peer reviewe