155 research outputs found

    Small and large scale segmental motion in polymers: Estimating cooperativity length by ordinary relaxation experiments

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    We derive a suitable expression for estimating the size of the cooperatively rearranging regions (CRRs) in supercooled polymer melts by fitting data worked out by ordinary relaxation experiments carried out in isothermal conditions. As an example, the average CRR size in poly(n-butyl methacrylate) in proximity to the glass transition temperature is derived from a stress relaxation experiment performed by means of an atomic force microscopy setup. Good agreement is found with results in the literature derived from measurements of temperature fluctuations (the so-called Donth method). The temperature dependence of the CRR size is explored for poly(butadiene); in this case the segmental relaxation function is derived through a novel method for the analysis of the efficiency with which free induction decay echoes are refocused in 1H NMR experiments. It is found that the CRR size increases upon cooling. The results derived from the analysis of the NMR data are found to be in satisfactory agreement with those worked out from broadband dielectric spectroscopy data in the literatur

    Case Report: An Unusual Case of Biventricular Thrombosis in a COVID-19 Patient With Ischemic Dilated Cardiomyopathy Assessment of Mass Mobility and Embolic Risk by Tissue Doppler Imaging

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein binds to angiotensin-converting enzyme 2 (ACE2) receptor on vascular cells. As a consequence, patients with COVID-19 have an increased incidence of thromboembolic complications of the SARS-CoV-2 infection and subsequent endothelial cell damage with consequence of development of systemic vasculitis and diffuse intravascular coagulation. The present case describes a COVID-19 female patient with ischemic dilated cardiomyopathy, who presented with congestive heart failure and echocardiographic evidence of biventricular apical thrombi. The peak antegrade longitudinal velocity (Va) of each thrombotic mass was measured by pulsed wave tissue Doppler imaging (PW-TDI). Both left ventricular and right ventricular apical thrombi were found with a TDI-derived mass peak Va < 10 cm/s. There was no clinical evidence of neither systemic nor pulmonary embolization, probably due to the hypomobility of both left and right ventricular masses

    UHV Deposition and Characterization of a Mononuclear Iron(III) \u3b2-diketonate Complex on Au(111)

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    The adsorption of the sterically hindered \u3b2-diketonate complex Fe(dpm)3, where Hdpm = dipivaloylmethane, on Au(111) was investigated by ultraviolet photoelectron spectroscopy (UPS) and scanning tunnelling microscopy (STM). The high volatility of the molecule limited the growth of the film to a few monolayers. While UPS evidenced the presence of the \u3b2-diketonate ligands on the surface, the integrity of the molecule on the surface could not be assessed. The low temperature STM images were more informative and at submonolayer coverage they showed the presence of regular domains characterized by a flat morphology and height of 480.3 nm. Along with these domains, tetra-lobed features adsorbed on the kinks of the herringbone were also observed. DFT-simulated images of the pristine molecule and its possible decomposition products allowed to assess the partial fragmentation of Fe(dpm)3 upon adsorption on the Au(111) surface. Structural features with intact molecules were only observed for the saturation coverage. An ex situ prepared thick film of the complex was also investigated by X-ray magnetic circular dichroism (XMCD) and features typical of high-spin iron(III) in octahedral environment were observed

    Separation from mechanical ventilation and survival after spinal cord injury: a systematic review and meta-analysis

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    Abstract Background Prolonged need for mechanical ventilation greatly impacts life expectancy of patients after spinal cord injury (SCI). Weaning outcomes have never been systematically assessed. In this systematic review and meta-analysis, we aimed to investigate the probability of weaning success, duration of mechanical ventilation, mortality, and their predictors in mechanically ventilated patients with SCI. Methods We searched six databases from inception until August 2021 for randomized-controlled trials and observational studies enrolling adult patients (≥ 16 years) with SCI from any cause requiring mechanical ventilation. Titles and abstracts were screened independently by two reviewers. Full texts of the identified articles were then assessed for eligibility. Data were extracted independently and in duplicate by pairs of authors, using a standardized data collection form. Synthetic results are reported as meta-analytic means and proportions, based on random effects models. Results Thirty-nine studies (14,637 patients, mean age 43) were selected. Cervical lesions were predominant (12,717 patients had cervical lesions only, 1843 in association with other levels’ lesions). Twenty-five studies were conducted in intensive care units (ICUs), 14 in rehabilitative settings. In ICU, the mean time from injury to hospitalization was 8 h [95% CI 7–9], mean duration of mechanical ventilation 27 days [20–34], probability of weaning success 63% [45–78] and mortality 8% [5–11]. Patients hospitalized in rehabilitation centres had a greater number of high-level lesions (C3 or above), were at 40 days [29–51] from injury and were ventilated for a mean of 97 days [65–128]; 82% [70–90] of them were successfully weaned, while mortality was 1% [0–19]. Conclusions Although our study highlights the lack of uniform definition of weaning success, of clear factors associated with weaning outcomes, and of high-level evidence to guide optimal weaning in patients with SCI, it shows that around two-thirds of mechanically ventilated patients can be weaned in ICU after SCI. A substantial gain in weaning success can be obtained during rehabilitation, with additional duration of stay but minimal increase in mortality. The study is registered with PROSPERO (CRD42020156788)

    The role of life cycle thinking-based methodologies in the development of waste management plans

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    The aim of this article is to examine how Life Cycle Thinking (LCT) contributes to the development of Waste Management Plans (WMPs). The case of Italy has been deeply investigated. The article first analyses whether and how the LCT methodologies were applied to the 21 regional WMPs; then, it draws indications for using LCT in the preparation of a WMP. Moreover, it outlines why the Life Cycle Assessment (LCA) methodology could be used as a powerful tool for regional planning in the waste field, analysing the indications for preparing a WMP that already exist at the European level and in the Italian National WM Programme. Results reveal that only four of the 21 regional WMPs include comprehensive and site-specific LCA studies. Building on these case study results, insights into the opportunities and benefits associated with incorporating LCT methodologies into WMP development and implementation are provided. This study underscores the critical importance of LCT and LCA in promoting sustainable waste management practices, ensuring compliance with European directives, and offering a foundation for more informed regional planning strategies

    APPLICAZIONI DELLA METODOLOGIA LCA NEL CAMPO DELLA GESTIONE E DEL TRATTAMENTO DEI RIFIUTI

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    L\u2019articolo nasce da un\u2019iniziativa del gruppo di lavoro \u201cGestione e trattamento dei rifiuti\u201d dell\u2019Associazione Rete Italiana LCA (Life Cycle Assessment). L\u2019obiettivo principale del gruppo di lavoro \ue8 quello di ampliare le conoscenze relative alla specificit\ue0 della metodologia LCA applicata ai processi di gestione e di trattamento dei rifiuti. L\u2019articolo riporta otto casi studio condotti da alcuni dei partecipanti al gruppo di lavoro, con il duplice obiettivo di mostrare il vasto campo di applicazione della metodologia LCA pur mantenendosi all\u2019interno del settore rifiuti e le specificit\ue0 dell\u2019applicazione di tale metodologia ai processi di gestione e trattamento dei rifiuti. Gli otto casi studio sono stati raggruppati per macro-finalit\ue0 dell\u2019applicazione, ossia: LCA applicata per valutare i benefici ottenibili dal recupero di varie tipologie di rifiuti, LCA a supporto della pianificazione regionale e/o nazionale e LCA a supporto dell\u2019economia circolare

    Stiffer Spleen Predicts Higher Bone Marrow Fibrosis and Higher JAK2 Allele Burden in Patients With Myeloproliferative Neoplasms

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    A total of 63 myeloproliferative neoplasms [MPN; 9 polycythemia vera (PV), 32 essential thrombocythemia (ET), and 22 myelofibrosis (MF)] underwent spleen stiffness (SS) measurement by vibration-controlled transient elastography equipped with a novel spleen-dedicated module. Higher SS values significantly correlated with grade 2-3 bone marrow (BM) fibrosis (p=0.035), with hemoglobin level <10 g/dl (p=0.014) and with white blood cells 6510,000/ml (p=0.008). Median SS was significantly higher in MF patients compared to ET and PV (p=0.015). SS also correlated with higher JAK2 variant allele frequency (p=0.02). This study identifies SS as a potential noninvasive tool that reflects BM fibrosis and the mutational burden in MPN

    Paediatric Wolfram syndrome Type 1: should gonadal dysfunction be part of the diagnostic criteria?

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    AimsWolfram Syndrome Spectrum Disorder (WFS1-SD), in its “classic” form, is a rare autosomal recessive disease with poor prognosis and wide phenotypic spectrum. Insulin dependent diabetes mellitus (DM), optic atrophy (OA) diabetes insipidus (DI) and sensorineural deafness (D) are the main features of WFS1-SD. Gonadal dysfunction (GD) has been described mainly in adults with variable prevalence and referred to as a minor clinical feature. This is the first case series investigating gonadal function in a small cohort of paediatric patients affected by WFS1-SD.MethodsGonadal function was investigated in eight patients (3 male and 5 female) between 3 and 16 years of age. Seven patients have been diagnosed with classic WFS1-SD and one with non-classic WFS1-SD. Gonadotropin and sex hormone levels were monitored, as well as markers of gonadal reserve (inhibin-B and anti-Mullerian hormone). Pubertal progression was assessed according to Tanner staging.ResultsPrimary hypogonadism was diagnosed in 50% of patients (n=4), more specifically 67% (n=2) of males and 40% of females (n=2). Pubertal delay was observed in one female patient. These data confirm that gonadal dysfunction may be a frequent and underdiagnosed clinical feature in WFS1-SD.ConclusionsGD may represent a frequent and earlier than previously described feature in WFS1-SD with repercussions on morbidity and quality of life. Consequently, we suggest that GD should be included amongst clinical diagnostic criteria for WFS1-SD, as has already been proposed for urinary dysfunction. Considering the heterogeneous and elusive presentation of WFS1-SD, this clinical feature may assist in an earlier diagnosis and timely follow-up and care of treatable associated diseases (i.e. insulin and sex hormone replacement) in these young patients

    Non-Occlusive Mesenteric Ischemia in Children With Diabetic Ketoacidosis: Case Report and Review of Literature

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    IntroductionDespite the use of technology, recurrent diabetic ketoacidosis (DKA) prevention remains an unmet need in children and adolescents with T1D and may be accompanied by life-threatening acute complications. We present a rare case of non-occlusive mesenteric ischemia (NOMI) with overt manifestation after DKA resolution and a discussion of recent literature addressing DKA-associated NOMI epidemiology and pathogenesis in children and adolescents.Case PresentationA 13-year-old female with previously diagnosed T1D, was admitted at our emergency department with hypovolemic shock, DKA, hyperosmolar state and acute kidney injury (AKI). Mildly progressive abdominal pain persisted after DKA correction and after repeated ultrasound evaluations ultimately suspect for intestinal perforation, an intraoperative diagnosis of NOMI was made.ConclusionThe diagnosis of DKA-associated NOMI must be suspected in pediatric patients with DKA, persistent abdominal pain, and severe dehydration even after DKA resolution

    COVID-19-associated Guillain-Barré syndrome in the early pandemic experience in Lombardia (Italy)

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    Objective To estimate the incidence and describe clinical characteristics and outcome of GBS in COVID-19 patients (COVID19-GBS) in one of the most hit regions during the frst pandemic wave, Lombardia. Methods Adult patients admitted to 20 Neurological Units between 1/3–30/4/2020 with COVID19-GBS were included as part of a multi-center study organized by the Italian society of Hospital Neuroscience (SNO). Results Thirty-eight COVID19-GBS patients had a mean age of 60.7 years and male frequency of 86.8%. CSF albuminocytological dissociation was detected in 71.4%, and PCR for SARS-CoV-2 was negative in 19 tested patients. Based on neurophysiology, 81.8% of patients had a diagnosis of AIDP, 12.1% of AMSAN, and 6.1% of AMAN. The course was favorable in 76.3% of patients, stable in 10.5%, while 13.2% worsened, of which 3 died. The estimated occurrence rate in Lombardia ranges from 0.5 to 0.05 GBS cases per 1000 COVID-19 infections depending on whether you consider positive cases or estimated seropositive cases. When we compared GBS cases with the pre-pandemic period, we found a reduction of cases from 165 to 135 cases in the 2-month study period in Lombardia. Conclusions We detected an increased incidence of GBS in COVID-19 patients which can refect a higher risk of GBS in COVID-19 patients and a reduction of GBS events during the pandemic period possibly due to a lower spread of more common respiratory infectious diseases determined by an increased use of preventive measures
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