Attributes of High-Performance Electron Transport Layers for Perovskite Solar Cells on Flexible PET versus on Glass.

Electron transport layers (ETLs) play a fundamental role in perovskite solar cells (PSCs) through charge extraction. Here, we developed flexible PSCs on 12 different kinds of ETLs based on SnO2. We show that ETLs need to be specifically developed for plastic substrates in order to attain 15% efficient flexible cells. Recipes developed for glass substrates do not typically transfer directly. Among all the ETLs, ZnO/SnO2 double layers delivered the highest average power conversion efficiency of 14.6% (best cell 14.8%), 39% higher than that of flexible cells of the same batch based on SnO2-only ETLs. However, the cells with a single ETL made of SnO2 nanoparticles were found to be more stable as well as more efficient and reproducible than SnO2 formed from a liquid precursor (SnO2-LP). We aimed at increasing the understanding of what makes a good ETL on polyethylene terephthalate (PET) substrates. More so than ensuring electron transport (as seen from on-current and series resistance analysis), delivering high shunt resistances (R SH) and lower recombination currents (I off) is key to obtain high efficiency. In fact, R SH of PSCs fabricated on glass was twice as large, and I off was 76% lower in relative terms, on average, than those on PET, indicating considerably better blocking behavior of ETLs on glass, which to a large extent explains the differences in average PCE (+29% in relative terms for glass vs PET) between these two types of devices. Importantly, we also found a clear trend for all ETLs and for different substrates between the wetting behavior of each surface and the final performance of the device, with efficiencies increasing with lower contact angles (ranging between ∼50 and 80°). Better wetting, with average contact angles being lower by 25% on glass versus PET, was conducive to delivering higher-quality layers and interfaces. This cognizance can help further optimize flexible devices and close the efficiency gap that still exists with their glass counterparts.

Cardiac Rehabilitation in Advanced aGE after PCI for acute coronary syndromes: predictors of exercise capacity improvement in the CR-AGE ACS study.

BACKGROUND: The positive effect of cardiac rehabilitation (CR) on outcomes after acute coronary syndromes (ACS) is established. Nevertheless, enrollment rates into CR programs remain low, although ACS carry a high risk of functional decline particularly in the elderly. AIM: We aimed to determine if a multidisciplinary CR improves exercise capacity in an older population discharged after ACS systematically treated with PCI. METHODS: CR-AGE ACS is a prospective, single-center, cohort study. All patients aged 75+ years consecutively referred to Cardiac Rehabilitation outpatient Unit at Careggi University Hospital, were screened for eligibility. Moderate/severe cognitive impairment, disability in 2+ basic activities of daily living, musculoskeletal diseases, contraindication to Cardiopulmonary Exercise Test, and diseases with an expected survival < 6 months, were exclusion criteria. Participants attended a CR program, based on 5-day-per-week aerobic training sessions for 4 weeks. RESULTS: We enrolled 253 post-ACS patients with a mean age 80.6 ± 4.4 years. After CR, 136 (56.2%) 77 (31.3%) patients obtained, respectively, at least a moderate (∆+5%) or an optimal (∆+15%) increase in VO2peak. Baseline VO2peak (- 1 ml/kg/min: OR 1.18; 95% CI 1.09-1.28), the number of training sessions (+1 session: OR 1.07; 95% CI 1.01-1.15), and mild-to-moderate baseline disability (yes vs. no: OR 0.22; 95% CI 0.01-0.57) were the predictors of VO2peak changes. CONCLUSIONS: A CR program started early after discharge from ACS produces a significant increase in exercise capacity in very old patients with mild-to-moderate post-acute physical impairment. Baseline VO2peak, the number of training sessions, and the level of baseline disability are the independent predictors of improvement.

Lower extremity performance predicts length of hospital stay in older candidates to elective cardiac surgery.

INTRODUCTION: Prolonged hospital stay must be considered as risk factor for poor outcomes after cardiac surgery; different variables have been advocated as predictors of in-hospital stay. Nevertheless, most patients requiring prolonged hospital stay are frail older subjects; thus, we hypothesized a significant influence of pre-operative physical performance, as a frailty measure, on in-hospital stay after elective cardiac surgery. METHODS: In a prospective, single-center, cohort study we enrolled patients aged 75+ years referred to our Division of Cardiac Surgery at Careggi University Hospital, for their first elective cardiac surgery. All participants were preoperatively evaluated by a team composed by a cardiac surgeon, a cardiologist, an anaesthesist, and a geriatrician to assess global cardiac surgery risk; lower extremity performance was measured with the Short Physical Performance Battery-SPPB. RESULTS: A total of 518 patients were included in the study. Mean age was 79.5 ±â€¯3.3 years; 256 (49.4%) were women. Isolated coronary by pass graft was performed in 37 patients (7.1%), isolated valve surgery in 115 (22.0%), and combined cardiac surgery procedures in 366 (70,9%). In a multivariable model, SPPB score was strongly associated with hospital length of stay both as continuous, categorized and dichotomous variable (p < 0.001; p = 0.002; p = 0.002 respectively) in all study population, and in subgroup of patients candidate to cardiac surgery considered by the Society of Thoracic Surgeons calculator score (p = 0.023; p = 0.056; p = 0.013 respectively). CONCLUSIONS: Our findings support the use of pre-operative SPPB evaluation before elective cardiac surgery based on the independent ability to predict length of hospital stay.

Simple and effective deposition method for solar cell perovskite films using a sheet of paper.

Most laboratories employ spin coating with application of antisolvent to achieve high efficiency in perovskite solar cells. However, this method wastes a lot of material and is not industrially usable. Conversely, large area coating techniques such as blade and slot-die require high precision engineering both for deposition of ink and for gas or for electromagnetic drying procedures that replace, out of necessity, anti-solvent engineering. Here we present a simple and effective method to deposit uniform high-quality perovskite films with a piece of paper as an applicator at low temperatures. We fabricated solar cells on flexible PET substrates manually with 11% power conversion efficiency. Deposition after soaking the sheet of paper in a green antisolvent improved the efficiency by 82% compared to when using dry paper as applicator. This new technique enables manual film deposition without any expensive equipment and has the potential to be fully automated for future optimization and exploitation.

Telehealth Management and Risk Stratification of Older Patients With Chronic Heart Failure During COVID-19 Pandemic: Prognostic Evaluation of the TeleHFCovid19-Score.

OBJECTIVES: To evaluate 6-month risk stratification capacity of the newly developed TeleHFCovid19-Score for remote management of older patients with heart failure (HF) during the coronavirus disease 2019 pandemic. DESIGN: Monocentric observational prospective study. SETTING AND PARTICIPANTS: Older HF outpatients remotely managed during the first pandemic wave. METHODS: The TeleHFCovid19-Score (0-29) was obtained by an ad hoc developed multiparametric standardized questionnaire administered during telephone visits to older HF patients (and/or caregivers) followed at our HF clinic. Questions were weighed on the basis of clinical judgment and review of current HF literature. According to the score, patients were divided in progressively increasing risk groups: green (0-3), yellow (4-8), and red (≥9). RESULTS: A total of 146 patients composed our study population: at baseline, 112, 21, and 13 were classified as green, yellow, and red, respectively. Mean age was 81±9 years, and women were 40%. Compared to patients of red and yellow groups, those in the green group had a lower use of high-dose loop diuretics (P < .001) or thiazide-like diuretics (P = .027) and had reported less frequently dyspnea at rest or for basic activities, new or worsening extremity edema, or weight increase (all P < .001). At 6 months, compared with red (62.2%) and yellow patients (33.3%), green patients (8.9%) presented a significantly lower rate of the composite outcome of cardiovascular death and/or HF hospitalization (P < .001). Moreover, receiver operating characteristic curve analysis showed a high sensibility and specificity of our score at 6 months (area under the curve = 0.789, 95% CI 0.682-0.896, P < .001) with a score <4.5 (very close to green group cutoff) that identified lower-risk subjects. CONCLUSIONS AND IMPLICATIONS: The TeleHFCovid19-Score was able to correctly identify patients with midterm favorable outcome. Therefore, our questionnaire might be used to identify low-risk chronic HF patients who could be temporarily managed remotely, allowing to devote more efforts to the care of higher-risk patients who need closer and on-site clinical evaluations.

Laser-Scribing Optimization for Sprayed SnO2-Based Perovskite Solar Modules on Flexible Plastic Substrates.

Flexible perovskite solar cells (FPSCs) are prime candidates for applications requiring a highly efficient, low-cost, lightweight, thin, and even foldable power source. Despite record efficiencies of lab-scale flexible devices (19.5% on a 0.1 cm2 area), scalability represents a critical factor toward commercialization of FPSCs. Large-area automized deposition techniques and efficient laser scribing procedures are required to enable a high-throughput production of flexible perovskite modules (FPSMs), with the latter being much more challenging compared to glass substrates. In this work, we introduce the combined concept of laser scribing optimization and automatized spray-coating of SnO2 layers. Based on a systematic variation of the incident laser power and a comprehensive morphological and electrical analysis of laser-based cell interconnections, optimal scribing parameters are identified. Furthermore, spray-coating is used to deposit uniform compact SnO2 films on large-area (>120 cm2) plastic substrates. FPSCs with spray-coated SnO2 show comparable performance as spin-coated cells, delivering up to 15.3% efficiency on small areas under 1 sun illumination. When upscaling to large areas, FPSMs deliver 12% power conversion efficiency (PCE) and negligible hysteresis on 16.8 cm2 and 11.7% PCE on a 21.8 cm2 active area. Our perovskite devices preserved 78% efficiency when the active area increased from 0.1 to 16.8 cm2, demonstrating that our combined approach is an effective strategy for large-area manufacturing of perovskite devices on flexible substrates.

Protocol for Telehealth Evaluation and Follow-up of Patients With Chronic Heart Failure During the COVID-19 Pandemic.

Because of the Coronavirus Disease 2019 (COVID-19) pandemic, we were forced to cancel scheduled visits for nearly 150 patients followed in our heart failure (HF) outpatient clinic. Therefore, we structured a telephone follow-up, developing a standardized 23-item questionnaire from which we obtained the Covid-19-HF score. The questionnaire was built to reproduce our usual clinical evaluation investigating a patient's social and functional condition, mood, adherence to pharmacological and nonpharmacological recommendations, clinical and hemodynamic status, pharmacological treatment, and need to contact emergency services. The score was used as a clinical tool to define patients' clinical stability and timing of the following telephone contact on the basis of the assignment to progressively increasing risk score groups: green (0-3), yellow (4-8), and red (≥9). Here we present our experience applying the score in the first 30 patients who completed the 4-week follow-up, describing baseline clinical characteristics and events that occurred in the period of observation.

Cardiac rehabilitation protocols in the elderly.

Cardiac rehabilitation (CR) is a comprehensive multidisciplinary program individually tailored to the needs of patients with cardiovascular disease. Cardiovascular disease is prevalent in older adults and is the leading cause of death and major disability in adults ≥75 years of age. The mean age of patients eligible for CR is increasing, with greater complexity and specific geriatric features, such as multimorbidity, frailty, and disability. In this population, CR interventions should be aimed to prevent disability and preserve the residual functional capacity. Every patient should be assessed with a multidimensional evaluation that includes clinical, functional, emotional, cognitive and social domains. Exercise-based CR programs have shown to be effective in improving function and quality of life, by reducing disability and age-related deconditioning and contributing favorably to improved health outcomes in an aged population. Very old and frail patients seem to get an even greater potential benefit, and an early start after an acute event can prevent the post-hospital syndrome. Despite these proven benefits, CR is often underused in this population and a great effort should be done to encourage them to attend these programs. There are just a few studies about CR programs in very old and frail patients, therefore a future goal should be to fill this gap.

Investigation of hysteresis in hole transport layer free metal halide perovskites cells under dark conditions.

Recent research is a testimony to the fact that perovskite material based solar cells are most efficient since they exhibit high power conversion efficiency and low cost of fabrication. Various perovskite materials display hysteresis in their current-voltage characteristic which accounts for memory behaviour. In this paper, we demonstrate efficient non-volatile memory devices based on hybrid organic-inorganic perovskite (CH3NH3PbI3) as a resistive switching layer on a Glass/Indium Tin Oxide (ITO) substrate. Our perovskite solar cells have been developed over the fully solution processed electron transport layer (ETL) which is a combination of SnO2 and mesoporous (m)-TiO2 scaffold layers. Hysteresis behaviour was observed in the current-voltage analysis achieving high ratio of ON & OFF current under dark and ambient conditions. Proposed perovskite-based Glass/ITO/SnO2/m-TiO2/CH3NH3PbI3/Au device has a hole transport layer (HTL) free structure, which is mainly responsible for a large ratio of ON & OFF current. The presence of voids in the scaffold m-TiO2 layer are also accountable for increasing electron/hole path length which escalates the recombination rate at the surface of the ETL/perovskite interface resulting in large hysteresis in the I-V curve. This memristor device operates at a low energy due to SnO2 layer's higher electron mobility and wide energy band gap. Our experimental results also show the dependency of voltage scan range & rate of scanning on the hysteresis behaviour in dark conditions. This memristive behaviour of the proposed device depicts drift in hysteresis loop with respect to the number of cycles, which would have a significant impact in neuromorphic applications. Moreover, due to the identical fabrication process of the proposed perovskite-based memristor device and perovskite solar cells, this device could be integrated inside a photovoltaic array to work as a power-on-chip device, where generation and computation could be possible on the same substrate for memory and neuromorphic applications.

Role of Frailty on Risk Stratification in Cardiac Surgery and Procedures.

The number of older people candidates for interventional cardiology, such as PCI but especially for transcatheter aortic valve implantation (TAVI) , would increase in the future. Generically, the surgical risk, the amount of complications in the perioperative period, mortality and severe disability remain significantly higher in the elderly than in younger. For this reason it's important to determine the indication for surgical intervention, using tools able to predict not only the classics outcome (length of stay, mortality), but also those more specifically geriatrics, correlate to frailty: delirium, cognitive deterioration, risk of institutionalization and decline in functional status. The majority of the most used surgical risks scores are often specialist-oriented and many variables are not considered. The need of a multidimensional diagnostic process, focused on detect frailty, in order to program a coordinated and integrated plan for treatment and long term follow up, led to the development of a specific geriatric tool: the Comprehensive Geriatric Assessment (CGA). The CGA has the aim to improve the prognostic ability of the current risk scores to capture short long term mortality and disability, and helping to resolve a crucial issue providing solid clinical indications to help physician in the definition of on interventional approach as futile. This tool will likely optimize the selection of TAVI older candidates could have the maximal benefit from the procedure.