817 research outputs found

    Archivi di Architettura a Palermo. Memorie della cittĂ  (XVII-XX secolo)

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    Il volume raccoglie saggi relativi ad alcuni tra i principali archivi di disegni di architettura a Palermo, in relazione, dunque, anche agli architetti protagonisti: Basile, Palazzotto, Marvuglia, ed altri. Si tratta del catalogo della mostra dal titolo Il portale degli Architetti e degli Ingegneri: quando tecnica e arte si incontrano, curata dal MiBac-Soprintendenza Archivistica per la Sicilia nell'ambito delle Giornate Europee del Patrimonio 2011, Palermo, ex convento della Magione, 24 settembre-5 ottobre 2011). Pubblicato al'interno della Collana editoriale "La Lucertola, collana di Arti, Lettere e Scienze", n. 2. Presentazione di Marcello Fagiolo

    Detection, characterization and sizing of hydrogen induced cracking in pressure vessels using phased array ultrasonic data processing

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    Pressure vessels operating in sour service conditions in refinery environments can be subject to the risk of H₂S cracking resulting from the hydrogen entering into the material. This risk, which is related to the specific working conditions and to the quality of the steel used, shall be properly managed in order to maintain the highest safety at a cost-effective level. Nowadays the typical management strategy is based on a risk based inspection (RBI) evaluation to define the inspection plan used in conjunction with a fitness for service (FFS) approach in defining if the vessel, although presenting dangerous defects such as cracks, can still be considered “fit for purpose” for a given time window based on specific fracture mechanics analysis. These vessels are periodically subject to non-destructive evaluation, typically ultrasonic testing. Phased Array (PA) ultrasonic is the latest technology more and more used for this type of application. This paper presents the design and development of an optimized Phased Array ultrasonic inspection technique for the detection and sizing of hydrogen induced cracking (HIC) type flaws used as reference for comparison. Materials used, containing natural operational defects, were inspected in “as-service” conditions. Samples have then been inspected by means of a “full matrix capture” (FMC) acquisition process followed by “total focusing method” (TFM) data post processing. FCM-TFM data have been further post-processed and then used to create a 3D geometrical reconstruction of the volume inspected. Results obtained show the significant improvement that FMC/TFM has over traditional PA inspection techniques both in terms of sensitivity and resolution for this specific type of defect. Moreover, since the FMC allows for the complete time domain signal to be captured from every element of a linear array probe, the full set of data is available for post-processing. Finally, the possibility to reconstruct the geometry of the component from the scans, including the defects present in its volume, represents the ideal solution for a reliable data transferring process to the engineering function for the subsequent FFS analysi

    The Importance of Stereochemically Active Lone Pairs For Influencing Pb II and As III Protein Binding

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    The toxicity of heavy metals, which is associated with the high affinity of the metals for thiolate rich proteins, constitutes a problem worldwide. However, despite this tremendous toxicity concern, the binding mode of As III and Pb II to proteins is poorly understood. To clarify the requirements for toxic metal binding to metalloregulatory sensor proteins such as As III in ArsR/ArsD and Pb II in PbrR or replacing Zn II in ή‐aminolevulinc acid dehydratase (ALAD), we have employed computational and experimental methods examining the binding of these heavy metals to designed peptide models. The computational results show that the mode of coordination of As III and Pb II is greatly influenced by the steric bulk within the second coordination environment of the metal. The proposed basis of this selectivity is the large size of the ion and, most important, the influence of the stereochemically active lone pair in hemidirected complexes of the metal ion as being crucial. The experimental data show that switching a bulky leucine layer above the metal binding site by a smaller alanine residue enhances the Pb II  binding affinity by a factor of five, thus supporting experimentally the hypothesis of lone pair steric hindrance. These complementary approaches demonstrate the potential importance of a stereochemically active lone pair as a metal recognition mode in proteins and, specifically, how the second coordination sphere environment affects the affinity and selectivity of protein targets by certain toxic ions. Experimental and computational methods have been employed to study the influence of the lone pair of As III and Pb II for the binding of these ions in proteins using designed peptide models. The results show that the mode of coordination of As III and Pb II is greatly influenced by the steric bulk within the second coordination environment of the metals (see figure).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90414/1/chem_201102786_sm_miscellaneous_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/90414/2/2040_ftp.pd

    Classroom active breaks to increase children’s physical activity: A cross-sectional study in the province of Naples, Italy

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    Background: Classroom Active Breaks (CABs), short active sessions integrated in the school time, have been recognized as a promising tool to reduce sedentary behavior and increase Physical Activity (PA) levels in children. “AulAttiva” is a six-month CABs-based program implemented in primary schools of the province of Naples. The aim of this study was to evaluate its effectiveness by comparing PA and sedentary time of participating pupils respect to a control group, considering also their weight status. Methods: Four third-grade classes, each from 4 schools out of 32 participating in AulAttiva, and 4 third-grade classes, each from 4 schools out of 74 that did not take part, were randomly selected. Finally, 58 children composed the intervention group and 57 the control group. Age, gender, weight and height were registered for each participant. Weight status was classified as non-overweight and overweight/obesity. Sedentary time and PA were assessed through accelerometers along a school day. Results: Light PA was 4 min higher in the AulAttiva group with respect to controls (p = 0.046). Within the non-overweight children, the AulAttiva group spent less time in sedentary behavior and more time in light and total PA than controls. No significant differences were found between the overweight/obese subgroups. Conclusions: The results support the effectiveness of CABs in increasing PA during the school day. Greater effects were registered among normal weight pupils, suggesting the possible influence of weight status on children’s participation to the intervention. Further studies are needed to improve the compliance of overweight/obese children to this intervention

    Histamine plasma levels and elimination diet in chronic idiopathic urticaria

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    Abstract: Objective: The aim of this study was to evaluate the effects of an oligoantigenic and histamine-free diet on patients affected with chronic idiopathic urticaria (CIU). Design: Ten patients with chronic idiopathic urticaria were prescribed an oligoantigenic and histamine-free diet for 21 days, followed by serial and controlled reintroduction of foods during a further 70 days. Modification in clinical illness as well as histamine plasma levels, post-heparin plasma diamine oxidase (DAO) and intestinal permeability were evaluated. Results: The oligoantigenic and histamine-free diet induced a significant improvement of symptoms (P < 0.05). Moreover, CIU patients on free diet showed higher histamine plasma levels (P < 0.05 vs post-diet and vs controls) that fell to control levels during the oligoantigenic and histamine-free diet. Post-heparin plasma diamine oxidase values were slightly reduced and were unchanged during the diet as well as intestinal permeability, which was always normal in all patients. Conclusions: These data suggest that histamine plays a major role in chronic idiopathic urticaria. The finding of normal intestinal permeability suggests that a morphological damage of intestinal mucosa should be excluded in these patients. However, the presence of low levels of post-heparin plasma diamine oxidase may indicate a subclinical impairment of small bowel enterocyte function that could induce a higher sensitivity to histamine-rich or histamine-producing food

    Linearized texture of three-dimensional extracellular matrix is mandatory for bladder cancer cell invasion

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    In the fields of biomaterials and tissue engineering simulating the native microenvironment is of utmost importance. As a major component of the microenvironment, the extracellular matrix (ECM) contributes to tissue homeostasis, whereas modifications of native features are associated with pathological conditions. Furthermore, three-dimensional (3D) geometry is an important feature of synthetic scaffolds favoring cell stemness, maintenance and differentiation. We analyzed the 3D structure, geometrical measurements and anisotropy of the ECM isolated from (i) human bladder mucosa (basal lamina and lamina propria) and muscularis propria; and, (ii) bladder carcinoma (BC). Next, binding and invasion of bladder metastatic cell line was observed on synthetic scaffold recapitulating anisotropy of tumoral ECM, but not on scaffold with disorganized texture typical of non-neoplastic lamina propria. This study provided information regarding the ultrastructure and geometry of healthy human bladder and BC ECMs. Likewise, using synthetic scaffolds we identified linearization of the texture as a mandatory feature for BC cell invasion. Integrating microstructure and geometry with biochemical and mechanical factors could support the development of an innovative synthetic bladder substitute or a tumoral scaffold predictive of chemotherapy outcomes

    Pediatric Complicated Appendicitis During the COVID-19 Pandemic: A National Perspective

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    This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemicIntroduction: The COVID-19 pandemic has changed the public’s perception of safety in accessing healthcare across common surgical emergencies, including acute appendicitis in children. Here, we aim to determine whether the COVID-19 pandemic is associated with poorer appendicitis outcomes and predict that there are higher complicated appendicitis (CA) rates during this time. Methods: A retrospective cohort study was conducted in patients younger than 19 years with a new diagnosis of acute appendicitis. Rates of CA were compared in the pre- (3/1/2019-5/31/2019) and post-COVID (3/1/2020-5/31/2020) timeframes using the Pediatric Health Information System national database. The primary end point of interest was CA rates. Secondary end point of interest was hospital length of stay. A p value < 0.05 was significant. Results: Nationally, 6,212 patients had acute appendicitis pre-COVID compared with 5,372 post-COVID. The CA rate post-COVID was 33%, which was significantly higher than 30% CA rate pre-COVID, and the rate of uncomplicated appendicitis post-COVID was lower (p < 0.001). An overall increase in hospital length of stay nationally was observed for all patients treated post-COVID (p < 0.001), as well as in those with CA (p < 0.001). Conclusion: The COVID-19 pandemic is directly associated with higher disease burden in pediatric acute appendicitis. The healthcare system must understand its role in alleviating public fear in seeking healthcare for patients and their families to encourage timely medical care
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