Gold nanoparticles supported on functionalized silica as catalysts for alkyne hydroamination: A chemico-physical insight

Highly stable gold nanoparticles anchored on propynylcarbamate-functionalized silica (Au/SiO2@Yne) have been efficiently utilized for the heterogeneous hydroamination of phenylacetylene with aniline under different reaction conditions. In order to ascertain the eventual influence of surface silanol groups on the system activity and selectivity tailored modifications of Au/SiO2@Yne catalysts were pursued according to two different strategies, involving respectively functionalization with trimethylethoxysilane (Au/SiO2@Yne-TMS) or post-treatment with triethylamine (Au/SiO2@Yne-NEt3). The prepared materials were analysed by several complementary techniques such as Solid State NMR (SS NMR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD). A comparison of the resulting catalytic activities with that of the pristine Au/SiO2@Yne revealed a significant improvement for Au/SiO2@Yne-NEt3 in terms of both conversion and selectivity. Recycling and stability studies showed a catalytic activity decrease after the first run, due to the formation of polyphenylacetylene (PPhA) oligomers shielding the active sites. PPhA removal by sonication in acetone fully restored the catalytic activity and empowered the system with a good operational stability, a very crucial issue in view of eventual practical applications

Donor cell acute myeloid leukemia after hematopoietic stem cell transplantation for chronic granulomatous disease: a case report and literature review

The patient reported here underwent hematopoietic stem cell transplantation (HSCT) due to chronic granulomatous disease (CGD) caused by biallelic mutations of the NCF1 gene. Two years later, he developed AML, which was unexpected and was recognized via sex-mismatched chromosomes as deriving from the donor cells; the patient was male, and the donor was his sister. Donor cell leukemia (DCL) is very rare, and it had never been reported in patients with CGD after HSCT. In the subsequent ten years, the AML relapsed three times and the patient underwent chemotherapy and three further HSCTs; donors were the same sister from the first HSCT, an unrelated donor, and his mother. The patient died during the third relapse. The DCL was characterized since onset by an acquired translocation between chromosomes 9 and 11, with a molecular rearrangement between the MLL and MLLT3 genes-a quite frequent cause of AML. In all of the relapses, the malignant clone had XX sex chromosomes and this rearrangement, thus indicating that it was always the original clone derived from the transplanted sister's cells. It exhibited the ability to remain quiescent in the BM during repeated chemotherapy courses, remission periods and HSCT. The leukemic clone then acquired different additional anomalies during the ten years of follow-up, with cytogenetic results characterized both by anomalies frequent in AML and by different, non-recurrent changes. This type of cytogenetic course is uncommon in AML

Efficiency in isotetronic acid synthesis via a diamine-acid couple catalyzed ethyl pyruvate homoaldol reaction

L-Proline failed to act as an organocatalyst in the homoaldol reaction of ethyl pyruvate, however, it reacted with the ester to give an azomethine ylide that in turn underwent 1,3-dipolar cycloaddition with a second molecule of pyruvate. Direct catalytic homoaldol reaction of ethyl pyruvate was performed using an (S)-(+)-1-(2-pyrrodinylmethyl)-pyrrolidine/trifluoroacetic acid combination as organocatalyst. The use of polymer supported reagents allowed for the lactonization of the aldol and isolation of the isotetronic acid derivative in hydroxy-free for

Determination of Relative Configuration in Organic Compounds by NMR Spectroscopy and Computational Methods.

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Topical distribution of initial paresis of the limbs to predict clinically relevant spasticity after ischemic stroke: a retrospective cohort study

BACKGROUND: The degree of initial paresis relates to spasticity development in stroke patients. However, the importance of proximal and distal paresis in predicting spasticity after stroke is unclear. AIM: To investigate the role of topical distribution of initial limb paresis to predict clinically relevant spasticity in adults with stroke. DESIGN: Retrospective cohort study. METHODS: Seventy-two first-ever ischemic stroke patients were examined. At the acute phase of illness, demographics and the European Stroke Scale motor items (maintenance of outstretched arm position, arm raising, wrist extension, grip strength, maintenance of outstretched leg position, leg flexion, foot dorsiflexion) were evaluated. At six months after the stroke onset, spasticity was assessed at the upper and lower limb with the modified Ashworth Scale. Clinically relevant spasticity was defined as modified Ashworth Scale ≥3 (0-5). RESULTS: The degree of initial paresis of the proximal muscles of the upper limb and the distal muscles of the lower limb showed the strongest association and the best profile of sensitivity-specificity in predicting clinically relevant spasticity at the upper and lower limb, respectively. Younger age showed higher risk for developing clinically relevant spasticity in the upper limb. CONCLUSIONS: Our findings support the hypothesis that the initial degree of proximal paresis of the upper limb and distal paresis of the lower limb as well as age may be considered early predictors of clinically relevant spasticity in adults with ischemic stroke. CLINICAL REHABILITATION IMPACT: Our findings further improve the role of initial paresis as predictor of spasticity after stroke

An integrated approach using high time-resolved tools to study the origin of aerosols

Long-range transport of natural and/or anthropogenic particles can contribute significantly to PM10 and PM2.5 concentrations and some European cities often fail to comply with PM daily limit values due to the additional impact of particles from remote sources. For this reason, reliable methodologies to identify long-range transport (LRT) events would be useful to better understand air pollution phenomena and support proper decision-making.This study explores the potential of an integrated and high time-resolved monitoring approach for the identification and characterization of local, regional and long-range transport events of high PM. In particular, the goal of this work was also the identification of time-limited event. For this purpose, a high time-resolved monitoring campaign was carried out at an urban background site in Bari (southern Italy) for about 20days (1st-20th October 2011). The integration of collected data as the hourly measurements of inorganic ions in PM2.5 and their gas precursors and of the natural radioactivity, in addition to the analyses of aerosol maps and hourly back trajectories (BT), provided useful information for the identification and chemical characterization of local sources and trans-boundary intrusions. Non-sea salt (nss) sulfate levels were found to increase when air masses came from northeastern Europe and higher dispersive conditions of the atmosphere were detected. Instead, higher nitrate and lower nss-sulfate concentrations were registered in correspondence with air mass stagnation and attributed to local traffic source. In some cases, combinations of local and trans-boundary sources were observed. Finally, statistical investigations such as the principal component analysis (PCA) applied on hourly ion concentrations and the cluster analyses, the Potential Source Contribution Function (PSCF) and the Concentration Weighted Trajectory (CWT) models computed on hourly back-trajectories enabled to complete a cognitive framework and confirm the influence of aerosol transported from heavily polluted areas on the receptor site

Elucidating heteroatom influence on homonuclear 4J(H,H) coupling constants by DFT/NMR approach

We report the structural dependency of long range scalar J-coupling constant across four bonds as function of the dihedral angles Φ1 and Φ3. The calculated homonuclear coupling constants 4J(H,H), obtained at a density functional theory level, were measured between C(1)─X(2) and X(2)─C(3) bonds in three-term models, where C, N, O, and S were systematically used as the second atom of the alkyl structures (1-4). The 4J(H,H) calculated values, tabulated for variation of 30° for both Φ1 and Φ3, have disclosed an unexpected detectable coupling constant (4J(H,H) ≥ 1 Hz) across heteroatoms, useful to provide valuable structural information. A 2-methyl-1,3-dithiane sulfide (5) was used as a case study to prove the applicability and reliability of the calculated values to real issues. The 4J(H,H) values obtained at density functional theory for the system 4 have reproduced with good accuracy an unexpected experimental 4J(H2ax-H4ax) = 1.01 Hz of sulfide molecule (5), suggesting these calculated coupling constant values as a new powerful tool for the organic synthesis and stereochemical analysis