Crystal symmetry breaking and vacancies in colloidal lead chalcogenide quantum dots

Size and shape tunability and low-cost solution processability make colloidal lead chalcogenide quantum dots (QDs) an emerging class of building blocks for innovative photovoltaic, thermoelectric and optoelectronic devices. Lead chalcogenide QDs are known to crystallize in the rock-salt structure, although with very different atomic order and stoichiometry in the core and surface regions; however, there exists no convincing prior identification of how extreme downsizing and surface-induced ligand effects influence structural distortion. Using forefront X-ray scattering techniques and density functional theory calculations, here we have identified that, at sizes below 8 nm, PbS and PbSe QDs undergo a lattice distortion with displacement of the Pb sublattice, driven by ligand-induced tensile strain. The resulting permanent electric dipoles may have implications on the oriented attachment of these QDs. Evidence is found for a Pb-deficient core and, in the as-synthesized QDs, for a rhombic dodecahedral shape with nonpolar 110 facets. On varying the nature of the surface ligands, differences in lattice strains are found

PREDEX - Prenatal assessment and treatment of Congenital Adrenal Hyperplasia with Dexamethasone - A longitudinal Study of outcome measures for mother and child

PREDEX \ue8 un trial aperto, controllato, non randomizzato e multicentrico. Le madri con un neonato (caso indice) gi\ue0 affetto da forma severa di deficit di 21-idrossilasi verranno informate della possibilit\ue0 di ricevere Desametazone durante la loro successiva gravidanza. L\u2019analisi genetica molecolare verr\ue0 completata prima dell\u2019inclusione, per verificare la gravit\ue0 della malattia ed essere sicuri che la diagnosi prenatale possa essere eseguita rapidamente senza ambiguit\ue0. L\u2019analisi genetica verr\ue0 eseguita nel laboratorio di genetica dell\u2019U.O di Pediatria Prof. Cicognani di Bologna. La terapia prenatale verr\ue0 proposta solo all\u2019interno di questo trial. Il trattamento con Desametazone verr\ue0 iniziato possibilmente prima della settima settimana di gestazione, alla dose di 20 g/kg di peso pre-gravidanza, suddiviso in tre dosi giornaliere. Dopo 10 settimane di gestazione complete, verr\ue0 prelevato un campione di villi coriali, sui quali verr\ue0 eseguita la determinazione del sesso e l\u2019analisi del gene CYP21. La determinazione del sesso \ue8 attuata nel giro di 2-3 giorni mediante cariotipo \u2026\u2026 L\u2019analisi delle mutazioni del gene CYP21 \ue8 corroborata da analisi di linkage, come misura cautelativa per la complessa natura del locus e per escludere una possibile contaminazione del campione con DNA materno. L\u2019analisi di CYP21 viene completata generalmente nel giro di 1 settimana (massimo 2). Nel caso di un feto di sesso maschile o di una femmina non affetta, il desametazone verr\ue0 interrotto con dosi scalari nel giro di circa una settimana. Questi feti, pertanto, saranno stati esposti alla terapia prenatale per circa 5-6 settimane. I feti di sesso femminile affetti, saranno trattati fino al termine di gravidanza

Candida bloodstream infections in intensive care units: analysis of the extended prevalence of infection in intensive care unit study

To provide a global, up-to-date picture of the prevalence, treatment, and outcomes of Candida bloodstream infections in intensive care unit patients and compare Candida with bacterial bloodstream infection. DESIGN: A retrospective analysis of the Extended Prevalence of Infection in the ICU Study (EPIC II). Demographic, physiological, infection-related and therapeutic data were collected. Patients were grouped as having Candida, Gram-positive, Gram-negative, and combined Candida/bacterial bloodstream infection. Outcome data were assessed at intensive care unit and hospital discharge. SETTING: EPIC II included 1265 intensive care units in 76 countries. PATIENTS: Patients in participating intensive care units on study day. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of the 14,414 patients in EPIC II, 99 patients had Candida bloodstream infections for a prevalence of 6.9 per 1000 patients. Sixty-one patients had candidemia alone and 38 patients had combined bloodstream infections. Candida albicans (n = 70) was the predominant species. Primary therapy included monotherapy with fluconazole (n = 39), caspofungin (n = 16), and a polyene-based product (n = 12). Combination therapy was infrequently used (n = 10). Compared with patients with Gram-positive (n = 420) and Gram-negative (n = 264) bloodstream infections, patients with candidemia were more likely to have solid tumors (p < .05) and appeared to have been in an intensive care unit longer (14 days [range, 5-25 days], 8 days [range, 3-20 days], and 10 days [range, 2-23 days], respectively), but this difference was not statistically significant. Severity of illness and organ dysfunction scores were similar between groups. Patients with Candida bloodstream infections, compared with patients with Gram-positive and Gram-negative bloodstream infections, had the greatest crude intensive care unit mortality rates (42.6%, 25.3%, and 29.1%, respectively) and longer intensive care unit lengths of stay (median [interquartile range]) (33 days [18-44], 20 days [9-43], and 21 days [8-46], respectively); however, these differences were not statistically significant. CONCLUSION: Candidemia remains a significant problem in intensive care units patients. In the EPIC II population, Candida albicans was the most common organism and fluconazole remained the predominant antifungal agent used. Candida bloodstream infections are associated with high intensive care unit and hospital mortality rates and resource use

Outcomes from elective colorectal cancer surgery during the SARS‐CoV‐2 pandemic

Aim This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic. Method This was an international cohort study of patients undergoing elective resection of colon or rectal cancer without preoperative suspicion of SARS-CoV-2. Centres entered data from their first recorded case of COVID-19 until 19 April 2020. The primary outcome was 30-day mortality. Secondary outcomes included anastomotic leak, postoperative SARS-CoV-2 and a comparison with prepandemic European Society of Coloproctology cohort data. Results From 2073 patients in 40 countries, 1.3% (27/2073) had a defunctioning stoma and 3.0% (63/2073) had an end stoma instead of an anastomosis only. Thirty-day mortality was 1.8% (38/2073), the incidence of postoperative SARS-CoV-2 was 3.8% (78/2073) and the anastomotic leak rate was 4.9% (86/1738). Mortality was lowest in patients without a leak or SARS-CoV-2 (14/1601, 0.9%) and highest in patients with both a leak and SARS-CoV-2 (5/13, 38.5%). Mortality was independently associated with anastomotic leak (adjusted odds ratio 6.01, 95% confidence interval 2.58–14.06), postoperative SARS-CoV-2 (16.90, 7.86–36.38), male sex (2.46, 1.01–5.93), age >70 years (2.87, 1.32–6.20) and advanced cancer stage (3.43, 1.16–10.21). Compared with prepandemic data, there were fewer anastomotic leaks (4.9% versus 7.7%) and an overall shorter length of stay (6 versus 7 days) but higher mortality (1.7% versus 1.1%). Conclusion Surgeons need to further mitigate against both SARS-CoV-2 and anastomotic leak when offering surgery during current and future COVID-19 waves based on patient, operative and organizational risks