321 research outputs found

    A Catalytic One-Pot Synthesis of Indolyl Cyclobutanones

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    A general strategy for the synthesis of indolyl cyclobutanones via a tandem Bronsted acid catalyzed 2-hydroxycyclobutanone activation-indole nucleophilic addition has been exploited. The procedure leads to a wide range of 2- and 3-functionalized indole derivatives in good to high yields with broad substrate scope

    Tandem Baeyer–Villiger/Wittig/oxa-Michael addition: One-step to 5-substituted γ-lactones

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    The results reported in this study provide a practical protocol for the construction, in one single step of synthetically important γ-lactones in good yields starting from α-hydroxy cyclobutanone, H2O2 and several stabilized phosphonium ylides. Our synthetic strategy relies on a tandem Baeyer–Villiger oxidation/Wittig reaction/oxa-Michael addition

    Internal characterization of embankment dams using ground penetrating radar (GPR) and thermographic analysis: A case study of the Medau Zirimilis Dam (Sardinia, Italy)

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    The stability of embankment dams without an impermeable core depends on the characteristics of the face slab that prevents internal erosion, piping and eventual collapse of the structure. Under a Mediterranean climate, the impermeable asphaltic face slab is subjected to high solar radiation and consequent temperature changes, which can generate the creation of cracks and joints. The Medau Zirimilis Dam, located in the Casteddu River (Sardinia), is an embankment dam that has undergone seepage and continuous repairs in its asphalt face slab. These reparations have been conducted because of the occurrence of cracks and relative movement of different segments of the slab. To evaluate if seepage endangers the integrity of the dam, GPR was used, with different antennas (100, 250 and 500 MHz), along its crest and upstream and downstream faces, and the data were integrated with infrared thermographic images. Although geophysical data do not show structural changes affecting the main dam structure, deformation structures at shallow levels and in particular in the upstream face and along the crest of the dam have been identified. Such deformation affects the road atop the crest, the face slab and underlying levels, resulting in landslides that include material from several meters below the surface. The analysis permitted the identification of the origin of surficial cracks and their effects on the face slab. These sectors, independent of current movement, define the most unstable areas against water level changes that can affect the dam integrity. GPR analysis at the embankments usually has the handicap of high clay content that precludes electromagnetic wave penetration; however, in this case, the obtained resolution and extent of penetration using the different antennas was sufficient, due to the absence of an inner waterproof unit, and permitted the evaluation of the inner structure of the dam and the application of GPR for construction quality surveillance, internal structural characterization and dam monitoring

    Solvent-Free Synthesis of Quaternary Oxazolidine-2-thione β3-Amino Ester Analogs

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    A solvent-free organocatalyzed intermolecular cyclization reaction starting from β-substituted γ-hydroxy-α,β-unsaturated esters and aryl isothiocyanates proceeds via an aza-Michael addition to provide previously unknown quaternary oxazolidine-2-thione β3 amino ester analogs. A panel of diversely-substituted esters was investigated, including β,γ-disubstituted examples which provided the target molecules with very high cis diastereoselectivity

    Synthesis of cyclobutane-fused oxazolidine-2-thione derivatives

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    An expedient, solvent-free, mild base catalyzed intermolecular cyclization reaction has been developed to enable the one-pot synthesis of fourteen examples of cyclobutane-fused oxazolidine-2-thiones in good to high yields. Bicyclic structures of this type have not previously been described in the literature; they have a cis ring junction with both rings deviating slightly from planarity

    Risk Factors of Cystoid Macular Edema After Pars Plana Vitrectomy for Pseudophakic Retinal Detachment

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    Introduction: This study aimed to investigate the prevalence of cystoid macular edema after pars plana vitrectomy for the treatment of pseudophakic rhegmatogenous retinal detachment and identify possible related risk factors. Methods: A retrospective monocentric study was conducted within a cohort of pseudophakic patients undergoing vitrectomy for rhegmatogenous retinal detachment between January 2019 and December 2022. Demographic data, initial and intraoperative characteristics of rhegmatogenous retinal detachment, and postoperative data were analyzed. Cystoid macular edema was defined on optical coherence tomography exclusively. Results: A total of 164 eyes of 164 patients were included for analysis. The mean age of the patients at surgery was 65.7 ± 12.0 years. The mean best-corrected visual acuity was 2.1 ± 1.0 logMAR preoperatively and 1.0 ± 0.7 logMAR postoperatively. The mean follow-up was 13.4 ± 7.7 months. The prevalence of cystoid macular edema was 17.1% [9.8–26.4]. In multivariate analysis, severe proliferative vitreoretinopathy (relative risk 3.6 [1.3–9.7]) and laser retinopexy (relative risk 8.4 [1.1–64.7]) were independently and significantly associated with cystoid macular edema. Conclusion: The prevalence of cystoid macular edema in pseudophakic rhegmatogenous retinal detachment after pars plana vitrectomy was 17.1%. Severe proliferative vitreoretinopathy stage and the use of endolaser retinopexy were independent risk factors for development of cystoid macular edema

    Age- and sex-related variations in platelet count in Italy: a proposal of reference ranges based on 40987 subjects' data

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    BACKGROUND AND OBJECTIVES: Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. METHODS: We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. RESULTS: Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an extended reference interval that takes into account the differences in platelet count observed in different geographic areas. CONCLUSIONS: The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy

    Insights into the reactivity of 2-hydroxycyclobutanones with thiols corroborated by quantum chemical DFT investigations, NMR and Raman analysis

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    A general strategy for the synthesis of 2-substituted cyclobutanone sulfides via a tandem Br nsted acid-catalyzed nucleophile addition/ring contraction/C3-C4 ring expansion reaction sequence has been exploited. The procedure led to a wide panel of four-membered cyclic ketones in good to excellent yields and with broad substrate scope. Mechanistic aspects and kinetic parameters were investigated by quantum chemical DFT calculations, allowing us to rationalize the different reactivity of 2-aryl- and 2-alkyl-substituted 2-hydroxycyclobutanones towards thiol nucleophiles in reactions mediated by sulfonic acids. NMR and in situ Raman techniques were employed to better understand the reaction kinetics and parameters that affect the desired outcome

    Insulin pump failures in Italian children with Type 1 diabetes: retrospective 1-year cohort study

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    AimsInsulin pump failure and/or malfunction requiring replacement have not been thoroughly investigated. This study evaluated pump replacement in children and adolescents with Type 1 diabetes using insulin pump therapy.MethodsData were collected for all participants younger than 19 years, starting insulin pump therapy before 31 December 2013. For each child, age, disease duration, date of insulin pump therapy initiation, insulin pump model, failure/malfunction/replacement yes/no and reason were considered for the year 2013.ResultsData were returned by 40 of 43 paediatric centres belonging to the Diabetes Study Group of the Italian Society of Paediatric Endocrinology and Diabetology. In total, 1574 of 11 311 (13.9%) children and adolescents with Type 1 diabetes were using an insulin pump: 29.2% Animas VIBE, 9.4% Medtronic MiniMed 715/515, 34.3% Medtronic MiniMed VEO, 24.3% Accu-Check Spirit Combo and 2.8% other models. In 2013, 0.165 insulin pump replacements per patient-year (11.8% due to pump failure/malfunction and 4.7% due to accidental damage) were recorded. Animas VIBE (22.1%) and Medtronic MiniMed VEO (17.7%) were the most replaced.ConclusionsIn a large cohort of Italian children and adolescents with Type 1 diabetes, insulin pump failure/malfunction and consequent replacement are aligned with rates previously reported and higher in more sophisticated pump models
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