Excitons in CsPbBr3 Halide Perovskite.

Excitons in Bridgman grown halide perovskite CsPbBr3 single crystals were examined using photoluminescence (PL) spectroscopy to determine the nature of the electronic states. The photoluminescence intensity was strongly temperature-dependent and depended upon the specific exciton band. At low temperatures intrinsic disorder and its related shallow below bandgap tail states determine the emission properties. Photoluminescence at low temperature revealed the presence of several strong bands at the band edge that is attributed to free or trapped/bound excitons. This PL emission results from strong electron-phonon coupling with an average phonon energy Eph of 6.5 and 27.4 meV for the emissions, comparable to that observed in other perovskites. The Huang-Rhys parameter S was calculated to be 3.81 and 1.51, indicating strong electron-phonon coupling. The interactions between electrons and phonons produce small polarons that tend to bind charge carriers and result in trapped/bound excitons. The transient photoluminescence response of each specific band was studied, and the results indicated a multiphonon recombination process. Average PL lifetimes of ∼17 ns for free excitons and ∼38 ns for trapped/bound excitons were determined. The observed edge states could be associated with native defects such as vacancies and interstitials, as well as twinning due to the cubic-to-tetragonal phase transition in CsPbBr3. Elimination of the trapping sites for binding excitons could lead to improved charge transport mobilities, carrier lifetimes, and detector properties in this system.

Prevalence of liver injury and correlation with clinical outcomes in patients with COVID-19: systematic review with meta-analysis.

OBJECTIVE: Liver involvement of SARS-CoV-2 infection has been reported in several papers, but without homogeneous findings. We aimed to systematically review the prevalence of liver involvement in patients with SARS-CoV-2 infection at their hospital admission, and its correlation with disease severity and clinical outcomes in patients with or without pre-existing chronic liver disease. MATERIALS AND METHODS: We systematically searched PubMed, Embase, Web of Science, Medline, PMC, clinical trial registries, and other Coronavirus family publications for studies reporting data on SARS-CoV-2 infection or COVID-19 and liver function tests (LFTs) alterations, as well as clinical course of patients with chronic liver disease or cirrhosis. Case reports, preprints, editorials, reviews were excluded. We also revised literature to describe the background of liver involvement during SARS-CoV-2 infection. RESULTS: 36 studies, including 20724 patients with SARS-CoV-2 infection, were included. The pooled prevalence of LFTs abnormalities at admission was 46.9% (AST 26.5%, ALT 22.8%, GGT 22.5%, ALP 5.7%, tBIL 8.0%). ALT, AST, tBIL were independent predictors of disease severity (ALT OR 1.54, 95% CI 1.17-2.03; AST OR 3.17, 95% CI 2.10-4.77; tBIL OR 2.32, 95% CI 1.18-4.58) and in-hospital mortality (ALT OR 1.48, 95% CI 1.12-1.96; AST OR 4.39, 95% CI 2.68-7.18; tBIL OR 7.75, 95% CI 2.28-26.40). Heterogeneity among studies was high. The few available data also reported that COVID-19 was associated with increased risk of liver decompensation and mortality in patients with liver cirrhosis. CONCLUSIONS: LFTs alterations were reported in up to 47% of unselected patients with COVID-19 and were associated with severe disease or in-hospital mortality. In cirrhotic patients, COVID-19 was associated with high risk of liver decompensation or mortality.

Increased Faecalibacterium abundance is associated with clinical improvement in patients receiving rifaximin treatment.

Compositional and functional alterations of the gut microbiota are involved in the pathogenesis of several gastrointestinal diseases. Rifaximin is often used to induce disease remission due to its eubiotic effects on the gut microbiota. To investigate the correlation between changes in the gut microbiota composition and symptoms improvement in patients who present a clinical response to rifaximin treatment. Patients with ulcerative colitis (UC), Crohn's disease (CD), irritable bowel syndrome (IBS) and diverticular disease (DD) undergoing rifaximin treatment for clinical indication were enrolled in the study. Rifaximin was administered at the dose of 1,200 mg/day for 10 days. Faecal samples were collected at baseline and at the end of treatment; clinical improvement was assessed by Mayo score for UC, CD Activity Index (CDAI) for CD, IBS severity scoring system (IBS-SSS) for IBS and global symptomatic score (GSS) for DD. Twenty-five patients were included in the analysis and a clinical improvement was recorded for 10/25 (40%) of them. Microbial alpha diversity showed a slight increase in clinical responders (P=0.271), while it decreased in patients who did not improved (P=0.05). A significant post-treatment increase in Faecalibacterium abundance was observed in patients with a positive response (log2FC 1.959, P=0.042). Roseburia abundance decreased in both groups, whereas Ruminococcus decreased only in patients who clinically improved. Clinical improvement consequent to rifaximin treatment is associated with an increase in Faecalibacterium abundance. Achieving a positive shift in the gut microbiota composition seems a key event to obtain a clinical benefit from treatment.

Metformin versus dietary treatment in nonalcoholic hepatic steatosis: a randomized study.

OBJECTIVE: We aimed at evaluating whether the addition of low-dose metformin to dietary treatment could be an effective approach in nondiabetic patients with nonalcoholic fatty liver disease (NAFLD). METHODS: We carried out a 6-month prospective study in a series of overweight or obese patients with ultrasonographic diagnosis of hepatic steatosis. In total, 50 patients were enrolled and randomized into two groups: the first group (n=25) was given metformin (1 g per day) plus dietary treatment and the second group (n=25) was given dietary treatment alone. RESULTS: At the end of the study, the proportion of patients with echographic evidence of fatty liver was reduced in both the metformin (P<0.0001) and the diet group (P=0.029). Moreover, patient body mass index and waist circumference significantly decreased in both groups (P<0.001). Fasting glucose, insulin resistance (evaluated as homeostasis model assessment of insulin resistance (HOMA-IR)) and serum adiponectin decreased in both groups, although these changes reached statistical significance only in the metformin group. In this group, HOMA-IR decreased from 3.3+/-1.6 to 2.4+/-1.2 (P=0.003), whereas it decreased from 3.2+/-1.6 to 2.8+/-1.1 (not significant, NS) in the diet group. Similarly, the proportion of patients with impaired fasting glucose declined from 35 to 5% (P=0.04) in the metformin and from 32 to 12% (NS) in the diet group. At baseline, approximately 40% of patients in both groups met the diagnostic criteria of metabolic syndrome. This proportion decreased to 20% in the metformin group (P=0.008) and to 32% in the diet group (NS). CONCLUSIONS: In our 6-month prospective study, both low-dose metformin and dietary treatment alone ameliorated liver steatosis and metabolic derangements in patients with NAFLD. However, metformin was more effective than dietary treatment alone in normalizing several metabolic parameters in these patients.

Hepatitis C virus cirrhosis: prolonged sustained virological response in a patient after low-dose antiviral treatment.

Hepatitis C virus (HCV) infection is the most frequent cause of chronic liver disease in the western world. The ''gold standard'' treatment of chronic HCV infection currently involves the administration of pegylated interferon alpha (PEG-IFN) and ribavirin. The success of this therapy is demonstrated by sustained virological responses (SVR). Randomized trials and practice guidelines have reported that compensated HCV cirrhosis is an indication for treatment with PEG-IFN and ribavirin, not only to obtain SVR but also to increase survival and to reduce the development of cirrhotic sequelae. In particular, the literature has reported that antiviral treatment was associated with histological improvement of fibrosis in cirrhotic patients with SVR. Recently, the same authors have evaluated the efficacy and safety of different doses of antiviral treatment in patients with chronic HCV infection. The use of interferon has been limited due to associated side effects, particularly in cirrhotic patients. Consequently, therapeutic decisions should be made on an individual basis. The Authors report a case of a patient with compensated HCV liver cirrhosis, with associated severe thrombocytopenia and oesophageal varices, in which the administration of antiviral therapy at a dose lower than the therapeutic ''gold standard'' has achieved SVR and consequently improved clinical status.

Platelet aggregation index assay in the progress of physiological delivery. Preliminary account.

I.A.P. during pregnancy and parturition has been checked. The results appear to be in the normal range in all the cases; accordingly it looks reasonable to assume no relationship to be take place among IAP and individual steps that occur in the progress of parturition and post-parturition.

Creatine phosphokinase assay in the progress of delivery.

Serum CPKase activity in 30 women during pregnancy was detected. The maximum increase of activity appeared during the expulsive step of parturition. The CPKase activity after parturition, in the range between the eighth and the twentyfourth hours, drops at the normal level.

[Evaluation of platelet aggregation index (IAP) in athletes practicing rowing after administration of anti-inflammatory agents]. / Valutazione dell'indice di aggregazione piastrinica (I.A.P.) in atleti praticanti canottaggio dopo somministrazione di antin-fiammatorio.

The AA. measured the Platelets Aggregation Index (I.A.P.) in two groups of oarsmen: the first treated with an anti-inflammatory drug and the second (control) without any drug. They found a statistically significant difference of the I.A.P. in the two groups.

[Enzymatic changes in the lymph in the thoracic duct and right lymphatic duct during extracorporeal circulation in the dog (author's transl)]. / Modifications enzymatiques de la lymphe du canal thoracique et du canal lymphatique droit au cours de la circulation extracorporelle chez le chien.

The authors analysed the various enzymes in the lymph of the thoracic duct and the right lymphatic duct in a series of 15 dogs submitted to extracorporeal circulation, the experimentors noted a series of diffuse cellular lesions which involved transiently the main organs. This lesion seems only to occur at first; independent of the duration of the by-pass, probably due to hypoxia following the rapid and massive introduction of priming. Our conclusion from this research is that lymph analysis is more revealing for knowledge of enzyme behaviour than blood analysis. A differential study of lymph in the right lymphatic duct and in the thoracic duct is surprisingly much less important.