The use of mechanically-fastened fibre-reinforced polymer (MF-FRP) strips has been recently proposed as a possible alternative solution to the most common externally-bonded (EB) sheets and laminates. ...Although several applications of MF-FRP strengthening on reinforced concrete (RC) structures are already available, further experimental and theoretical studies are needed for both achieving a thorough knowledge of their mechanical behaviour and formulating sound design rules.
The present paper deals with identifying the relationships between the actual bearing stress transferred by the fastener and the corresponding relative displacement (slip) at the FRP–concrete interface. For this purpose, a simplified numerical model is firstly formulated to simulate the experimental behaviour observed from direct shear tests (DSTs) recently performed by the Authors on FRP laminates fastened to concrete blocks with screwed steel anchors. Then, the numerical model is employed within an optimisation procedure aimed at indirectly identifying the relationships between the force applied on the single fastener and the corresponding displacement. Finally, the results of this inverse identification procedure are compared for pointing out the differences possibly arising in terms of interface stress–slip relationship as a result of different detailing in the fastening system. In particular, the cases of fasteners with or without steel washers are investigated.
The use of Mechanically Fastened Fiber Reinforced Polymer (MF-FRP) laminates is emerging as a viable alternative to adhesively bonded FRP laminates for the rehabilitation of reinforced concrete (RC) ...members such as beams and slabs. A recently published state-of-the-art review of the experimental research has demonstrated the viability and effectiveness of MF-FRP systems. This paper provides a state-of-the-art review of the analytical and numerical studies performed over the last decade with the aim of: (a) predicting the strength, the load-deformation response and the failure mode of rehabilitated RC members, and (b) accounting for the interfacial behavior between the concrete and the MF-FRP laminate. Ultimate strength models and constitutive models are critically reviewed based on their key assumptions and formulations and compares the analytical predictions with previously reported experimental results.
Nowadays existing reinforced concrete (RC) structures are often repaired and/or strengthened by using Fibre Reinforced Polymer (FRP) systems. Although externally bonded FRP (EB-FRP) systems are still ...the most widely employed ones, recent experimental studies and some field applications have demonstrated the potential of mechanically fastened FRP (MF-FRP) laminates for strengthening RC beams and slabs. The advantages of this new technique with respect to the use of EB-FRP systems are mainly in the ease of installation and the higher restraint to the possible delamination of the FRP system from the concrete surface.
This paper presents a new Finite Element (FE) model capable of simulating the flexural behaviour of RC beams or slabs strengthened by using MF-FRP strips. Nonlinear bearing-stress-interface-slip laws are considered to describe the behaviour of the mechanical connection between the RC beam and the FRP strip, whereas well-established stress–strain relationships are adopted to model the behaviour of concrete, longitudinal reinforcing steel rebars and composite laminate. The model has been validated by comparing the numerical predictions with several experimental results found in the scientific literature. A good agreement has been observed between experimental and numerical results thus confirming the accuracy of the proposed model.
Recently, the use of Mechanically Fastened Fiber-Reinforced Polymer (MF-FRP) systems has emerged as a viable means for flexural strengthening of reinforced concrete members. The technique is suitable ...for emergency repairs where constructability and speed of installation are critical requirements. The MF-FRP system consists of pre-cured FRP laminates with enhanced longitudinal bearing strength that are attached to the concrete substrate by means of mechanical steel anchors. This research project presents an experimental investigation comprising a series of flexural tests on scaled one-way RC slabs. The test matrix includes MF-FRP strengthened specimens, a counterpart with the externally bonded (EB) FRP reinforcement, and a control specimen. The effects of fastener layout and laminate length on strength increase and failure mode were studied. It is shown that with proper selection of fastener layout the MF-FRP system results in a significant deformability and strength increase, where the latter is comparable to that attained using EB-FRP sheets. Specific gaps on the existing analytical procedures for flexural strengthening with MF-FRP systems are finally discussed.
Diabetes insipidus--diagnosis and management Di Iorgi, Natascia; Napoli, Flavia; Allegri, Anna Elsa Maria ...
Hormone research in paediatrics,
01/2012, Letnik:
77, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Central diabetes insipidus (CDI) is the end result of a number of conditions that affect the hypothalamic-neurohypophyseal system. The known causes include germinoma/craniopharyngioma, Langerhans ...cell histiocytosis (LCH), local inflammatory, autoimmune or vascular diseases, trauma resulting from surgery or an accident, sarcoidosis, metastases and midline cerebral and cranial malformations. In rare cases, the underlying cause can be genetic defects in vasopressin synthesis that are inherited as autosomal dominant, autosomal recessive or X-linked recessive traits. The diagnosis of the underlying condition is challenging and raises several concerns for patients and parents as it requires long-term follow-up. Proper etiological diagnosis can be achieved via a series of steps that start with clinical observations and then progress to more sophisticated tools. Specifically, MRI identification of pituitary hyperintensity in the posterior part of the sella, now considered a clear marker of neurohypophyseal functional integrity, together with the careful analysis of pituitary stalk shape and size, have provided the most striking findings contributing to the diagnosis and understanding of some forms of 'idiopathic' CDI. MRI STIR (short-inversion-time inversion recovery sequencing) is a promising technology for the early identification of LCH-dependent CDI.
SARS-Cov2 infection has recently spread to Italy with important consequences on pregnancy management, mother and child health and mother–child contact. Breastfeeding improves the health of mother and ...child and reduces risk of neonatal infection with other pathogens that are likely to cause serious illness.
To date no evidence confirmed COVID-19 vertical transmission from infected pregnant mother to their fetus. However it is well known that an infected mother can transmit the COVID-19 virus through respiratory droplets during breastfeeding or intimate contact.
Thus, the mothers with known or suspected COVID-19 should adhere to standard and contact precautions during breastfeeding.
Woman Study Group of AMD, after reviewing current knowledge about COVID-19 vertical transmission and the compatibility of breastfeeding in COVID-19 mother, the available recommendations from Health Care Organizations and main experts opinions, issued the following suggestions on breastfeeding during the COVID-19 pandemic, addressed both to mothers with and without diabetes.
It should be considered that following suggestions may change in the future when more evidence is acquired regarding SARS-Cov2 infection.
In this paper, the electronic transduction of DNA hybridization is presented by coupling organic charge-modulated field-effect transistors (OCMFETs) and hairpin-shaped probes. These probes have shown ...interesting properties in terms of sensitivity and selectivity in other kinds of assays, in the form of molecular beacons (MBs). Their integration with organic-transistor based sensors, never explored before, paves the way to a new class of low-cost, easy-to-use, and portable genetic sensors with enhanced performances. Thanks to the peculiar characteristics of the employed sensor, measurements can be performed at relatively high ionic strengths, thus optimizing the probes' functionality without affecting the detection ability of the device. A complete electrical characterization of the sensor is reported, including calibration with different target concentrations in the measurement environment and selectivity evaluation. In particular, DNA hybridization detection for target concentration as low as 100 pM is demonstrated.
Capillary leak syndrome (CLS) emerged as new adverse event after immunization (AEFI) associated to COVID-19 vaccination. CLS is a rare condition characterized by increased capillary permeability, ...resulting in hypoalbuminemia, hypotension, and edema mainly in the upper and lower limbs. Our pharmacovigilance study aims to evaluate the CLS onset following receipt of COVID-19 mRNA vaccines (mRNA-1273 and BNT162b2) compared to viral vector vaccines (Ad26.COV2-S and ChAdOx1-SARS-COV-2). We carried a cross-sectional study using all Individual Case Safety Reports (ICSRs) reporting a COVID-19 vaccine as suspected drug and CLS as AEFI, which were collected in the pharmacovigilance database EudraVigilance from January 1st, 2021, to January 14th, 2022. We applied the Reporting Odds Ratio (ROR) 95% CI for the disproportionality analysis. During our study period, CLS was described as AEFI in 84 out of 1,357,962 ICRs reporting a vaccine COVID-19 as suspected drug and collected in the EV database. Overall, the ICSR reported by CLS were mainly related to the viral vector COVID-19(ChAdOx1-SARS-COV-2 = 36; Ad26.COV2-S = 9). The mRNA COVID-19 vaccines were reported in 39 ICSRs (BNT162b2 =33; mRNA-1273 =6). Majority of ICSRs were reported by healthcare professionals (71.4%). Majority of the patients were adult (58.3%) and the female gender accounted in more than 65% of ICSRs referred both to classes vaccines. In particular, women were more represented in ICSRs referred to mRNA-1273 (83.3%) and to ChAdOx1-SARS-COV-2 (72.2%). The CLS outcome was more frequently favorable in mRNA ICSRs (33,3%) than the viral vector ones (13.3%). Among the ICSRs reporting CLS with unfavorable outcome, we found also 9 fatal cases (BNT162b2 = 1; ChAdOx1-SARS-COV-2 = 4; Ad26.COV2-S = 4). From disproportionality analysis emerged a lower CLS reporting probability after vaccination with mRNA vaccines compared to viral vector-based ones (ROR 0.5, 95% CI 0.3–0.7; p <0.001).Our findings, even if subject to the limitations of spontaneous reporting systems, suggest a small but statistically significant safety concern for CLS following receipt of COVID-19 viral vector vaccines, in particular with Ad26.COV2-S. Cytokine-release following T-cell activation could be involved in CLS occurrence, but a precise mechanism has been not yet identified. COVID-19 vaccines remain attentive as possible triggers of CLS.
At the end of 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak spread from China all around the world, causing thousands of deaths. In Italy, the hardest hit region was ...Lombardy, with the first reported case on 20 February 2020.
San Raffaele Scientific Institute - a large tertiary hospital and research centre in Milan, Italy - was immediately involved in the management of the public health emergency. Since the beginning of the outbreak, the elective surgical activity of the hospital was rapidly reduced and large areas of the hospital were simultaneously reorganised to admit and assist patients with coronavirus disease 2019 (COVID-19). In addition, the hospital became the regional referral hub for cardiovascular emergencies in order to keep ensuring a high level of health care to non-COVID-19 patients in northern Italy.
In a few days, a COVID-19 emergency department was created, improving the general ward capacity to a total number of 279 beds dedicated to patients with COVID-19. Moreover, the number of intensive care unit (ICU) beds was increased from 28 to 72 (54 of them dedicated to patients with COVID-19, and 18 to cardiology and cardiac surgery hub emergencies), both converting pre-existing areas and creating new high technology spaces.
All the involved health care personnel were rapidly trained to use personal protection equipment and to manage this particular category of patients both in general wards and ICUs.
Furthermore, besides clinical activities, continuously important research projects were carried out in order to find new strategies and more effective therapies to better face an unprecedented health emergency in Italy.
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