Impact of Alkyl Chain Length on the Formation of Regular- and Reverse-Graded Quasi-2D Perovskite Thin Films

Crystallization of low-dimensional perovskites is a complex process that leads to multidimensional films comprising two-dimensional (2D), quasi-2D, and three-dimensional (3D) phases. Most quasi-2D perovskite films possess a regular gradient with 2D phases located at the bottom of the film and 3D phases at the top. Recently, multiple studies have reported reverse-graded perovskite films, where the location of the 2D and 3D structures is inverted. The underlying reasons for such a peculiar phase distribution are unclear. While crystallization of regular-graded quasi-2D perovskites has been described as starting with 3D phases from the liquid-air interface, the film formation of reverse-graded films has not been investigated yet. Here, we examine the impact of the alkyl chain length on the formation of regular- and reverse-graded perovskites using n-alkylammonium ions. We find that long alkyl chains reverse the phase distribution gradient. By combining photoluminescence spectroscopy with in situ optical absorption measurements, we demonstrate that crystallization starts at the liquid-N2 interface, though as 3D phases for short-chain n-alkylammonium ions and as quasi-2D phases for long chains. We link this behavior to enhanced van der Waals interactions between long-chain n-alkylammonium ions in polar solvents and their tendency to accumulate at the liquid-N2 interface, creating a concentration gradient along the film thickness.</p

Clinical characteristics and cardiovascular implications of the dead patients for COVID-19:

Coronavirus Disease 2019 (COVID-19) caused by 2019 novel coronavirus (named SARS-CoV-2), has become a global pandemic. Aged population with cardiovascular diseases is usually more susceptible to SARS-CoV-2 infection with an increased risk of severe complications and elevated case-fatality rate. Despite of several researches about COVID-19, cardiovascular implications related to this infection still remain largely unclear. The aim of this study is to evaluate the clinical characteristics of dead patients with COVID-19. We enrolled all patients with more than 50 years of age with laboratory confirmed COVID-19, admitted to infectious clinical diseases PO SS Annunziata of Chieti (Italy) from March 2020 to April 2020 who died during hospitalization. Demographics, underlying comorbidities, clinical symptoms and signs, laboratory results, computed tomography of the chest, treatment measures, and outcome data were collected. We enrolled eight patients, the age was 82 ± 9.7 years, four female and four male. All patients had comorbidity, such as hypertension (7 [87.5%]), diabetes (1 [12.5%]), and heart disease (6 [75%]). Common symptoms included fever [8 (100%)], dry cough (1[12.56%]), and dyspnea (3 [37.5%]). All patients [8 (100%)] showed local and/or bilateral patchy shadowing on chest computed tomography that is the typical radiological finding in COVID-19. Lymphopenia was observed in seven patients (87.5%). All patients showed elevated troponin and prolongation of the QTc interval ( p < 0.05). In this study we demonstrated that in SARS-CoV-2 infection, the deaths occurred in the non-ICU population with more than 50 years are related to cardiac causes. In our cases elongation of QTc and alteration in troponin are present in all patients who died and could represent a data to better stratify the population at risk. More detailed research on cardiovascular involvement in COVID-19 patients with sudden deaths showed a predictive role of troponin and QTc elongation

number of mediastinal lymph nodes as a prognostic factor in pn2 non small cell lung cancer a single centre experience and review of the literature

Lung cancer is one of the most common cause of cancer-related death for men and women in the world. The prevalent histology is non-small cell lung carcinoma (NSCLC), including squamous cell carcinoma, adenocarcinoma and large cell carcinoma (Moretti et al., 2009), with a 5year survival rate of 67% (stage IA) to <5% (stage IV) (End, 2006). Currently the most important predictor of survival in lung cancer is the stage (TNM) (Kligerman and Abbot, 2010; Goldstraw, 2009). Despite the new staging system (Kligerman and Abbot, 2010), stage III NSCLC remains a very heterogeneous disease , with a 5-year survival rate ranging from 35% to 5%. There are two major treatment targets for of patients with stage III : locoregional control and control of micrometastases, preventing distant metastatic disease (Penland et al., 2004; Bradley et al., 2005). The standard of care is represented by multimodality treatment, comprehending surgery for resectable disease, perioperative chemotherapy and radiation therapy (RT) for patients with pathological (p) N2 disease (Okamoto, 2008). In current TNM classification system, N category is defined exclusively by anatomic nodal location, though number of lymph nodes confirmed to be a fundamental prognostic factor as in other type of tumours. In our study, we assessed, in patients with stage III N2 category NSCLC disease, the prognostic value of the number of lymph nodes after multimodality treatment

An ecological study on the relationship between supply of beds in long-term care institutions in Italy and potential care needs for the elderly

<p>Abstract</p> <p>Background</p> <p>The ageing population in Europe is putting an ever increasing demand on the long-term care (LTC) services provided by these countries. This study analyses the relationship between the LTC institutional supply of beds and potential care needs, taking into account the social and health context, the supply of complementary and alternative services, along with informal care.</p> <p>Methods</p> <p>An observational, cross-sectional, ecological study was carried out. Statistical data were obtained from the Italian National Institute of Statistics and Ministry of Health. Indicators, regarding 5 areas (Supply of beds in long term care institutions, Potential care needs, Social and health context, Complementary and alternative services for the elderly, Informal care), were calculated at Local Health Unit (LHU) level and referred to 2004.</p> <p>Two indicators were specifically used to measure supply of beds in long term care institutions and potential care needs for the elderly. Their values were grouped in tertiles. LHU were classified according to the combination of tertiles in three groups: A. High level of supply of beds in long term care institutions associated with low level of potential care needs; B. Low level of supply of beds in long term care institutions associated with high level of potential care needs; C. Balanced level of supply of beds in long term care institutions with potential care needs. For each group the indicators of 5 areas were analysed.</p> <p>The Index Number (IN) was calculated for each of these indicators.</p> <p>Results</p> <p>Specific factors that need to be carefully considered were highlighted in each of the three defined groups. The highest level of alternative services such as long-stay hospital discharges in residence region (IN = 125), home care recipients (HCR) (IN = 123.8) were reported for Group A. This group included North regions. The highest level of inappropriate hospital discharges in (IN = 124.1) and out (IN = 155.8) the residence region, the highest value of families who received help (IN = 106.4) and the lowest level of HCR (IN = 68.7) were found in Group B. South regions belong to this group. The highest level of families paying a caregiver (IN = 115.8) was shown in Group C. Central regions are included in third group.</p> <p>Conclusion</p> <p>Supply of beds in long term care institutions substantially differs across Italian regions, showing in every scenario some imbalances between potential care needs and other studied factors. Our study suggests the need of a comprehensive rethinking of care delivery "system".</p

The X-ray Polarization Probe mission concept

The X-ray Polarization Probe (XPP) is a second generation X-ray polarimeter following up on the Imaging X-ray Polarimetry Explorer (IXPE). The XPP will offer true broadband polarimetery over the wide 0.2-60 keV bandpass in addition to imaging polarimetry from 2-8 keV. The extended energy bandpass and improvements in sensitivity will enable the simultaneous measurement of the polarization of several emission components. These measurements will give qualitatively new information about how compact objects work, and will probe fundamental physics, i.e. strong-field quantum electrodynamics and strong gravity.Comment: submitted to Astrophysics Decadal Survey as a State of the Profession white pape

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p &lt; .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p &lt; .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

Exploiting Perovskites Multidimensionality for High Performance Photodiodes

Quasi-2D perovskites (q2D PVKs) have emerged as attractive materials for optoelectronic devices, such as solar cells, LEDs, or photodiodes, because of their structural diversity and higher stability compared to the 3D counterpart. To develop high-performance perovskite photodiodes (PPDs), efforts have been put into minimizing their dark-current density (JD), as this figure of merit impacts the noise (in) and thereby the detectivity of the device. Our previous work has shown that, in absence of charge injection, a thermal charge generation mechanism occurring at the interface between the electron-blocking layer (EBL) and the perovskite is responsible for the experimental JD. This mechanism consists of a thermal excitation of an electron from the EBL HOMO to the conduction band (CB) of the perovskite and depends on the energy offset (Φ) between the abovementioned energy levels. A higher barrier directly translates into lower JD, hence to photodiodes with higher detectivity. In this regard, q2D PVKs are an excellent candidate material, as they usually consist of a 2D-3D gradient, where high-bandgap 2D or quasi-2D phases are located at the interface with the EBL (in a p-i-n device), resulting in an upshift of the CB and an increase of Φ.By means of solvent engineering and varying the organic spacers, we finely tuned this 2D-3D gradient and fabricated PPDs based on q2D PVK active layers. All 2D-3D graded perovskites exhibited a significant decrease of the average JD to about 5×10-8 mA cm-2, confirming the positive effect of introducing 2D phases at the EBL interface. Moreover, by performing temperature-dependent JD measurements, we determined the activation energy (Ea) of the thermal charge generation process and we found that indeed Ea increased from 0.87 eV to 1.16 eV, for 3D FAMA and quasi-2D perovskite BA2MA3Pb4I13, respectively. To confirm the importance of gradient direction, we fabricated devices with a 3D-2D gradient by using cyclohexylmethylammonium iodide as organic spacer and characterized the resulting films in depth. In this case, the 2D phases are located at the top of the film, whereas 3D ones are at the bottom, meaning that in such devices the EBL interface is by all means similar to when using a bulk 3D perovskite as active layer. Both JD and Ea were in fact found to be similar to the ones obtained for pure 3D perovskites, further confirming the importance of having a 2D-3D gradient to achieve low dark-current density.Despite several 2D-3D graded photodiodes have shown decreased JD, which is strictly related to their performance in dark conditions, other figures of merit related to PPDs behavior under illumination are equally important, such as EQE and response time. By measuring grazing-incidence wide-angle X-ray scattering (GIWAXS), we introduced a distinction between parallel- and perpendicular- oriented films, and we linked such crystal orientation to their light behavior. This study allowed us to select perpendicular-oriented q2D PVKs as optimal devices with low JD, high EQE (&gt; 80%), and fast response speed.Finally, as we proved that increasing Φ is crucial for obtaining low dark-current PPDs, we fabricated devices using the optimized q2D PVK films and a deep-HOMO EBL, namely PTAA:polyTPD. The combination of these materials allowed us to further increase Φ and minimize JD to 5×10−9 mA cm−2, which is the lowest JD reported in the literature to the best of our knowledge, leading to ultralow noise of 6 fA Hz−1/2 and to an outstanding real specific detectivity of 7×1012 Jones. Furthermore, such devices displayed exceptional light sensitivity, with a linear response over more than 8 orders of magnitude of light intensity.Overall, in our work we outlined several key requirements to exploit multidimensional perovskite films for high-performance perovskite photodiodes, paving the way for further developments in the field of PPDs