1,571 research outputs found
High strain rate effects in masonry structures under waterborne debris impacts
Masonry buildings are vulnerable to extreme hydrodynamic events such as floods or tsunamis. Post-disaster surveys have shown that waterborne debris impacts can significantly damage masonry walls during these events. To simulate these actions, the current design or research practice is to compute the force–time diagram of the impact and then use it for dynamic analyses. Standing on the current knowledge, debris impacts are highly impulsive, but it is not clear if such loads are fast enough to activate the high strain rate effects in masonry, i.e. the strain rate dependency of material properties. The present study aims to answer this question, for the first time, following nonlinear Finite Element (FE) simulations. Simulations are conducted on a masonry wall, following a micro-modelling strategy, subjected to water flow and waterborne debris impact under different scenarios. It is found that the strain rates exceed the critical threshold after which strain rate effects are considerable. Such a finding, initially obtained using the minimum design demand for log-type debris imposed by ASCE/SEI 7-22, is further extended to a range of impact force–time diagrams different in impact duration and peak force (corresponding to different debris properties or flow velocity). It is also shown that the impact location (i.e. midspan or close to the boundary) affects the strain rate magnitude because of the changes in the impact stiffness and the activated failure mechanisms. Furthermore, it is found that the dynamic tensile post-elastic behaviour of the materials is the most influencing parameter in the structural response. These results open a new area in the field of assessment and design of masonry structures to waterborne debris and guide the development of future experiments, numerical simulations or design relations
Guiding nipple-areola complex reconstruction.Lliterature review and proposal of a new decision-making algorithm
Background: Nipple-areola complex reconstruction (NAR) most commonly represents the finishing touch to breast reconstruction (BR). Nipple presence is particularly relevant to the patient’s psyche, beyond any shadow of doubt. Many reconstructive options have been described in time. Surgery is easy, but final result is often disappointing on the long run. Methods: The goal of this manuscript is to analyze and classify knowledge concerning NAR techniques and the factors that influence success, and then to elaborate a practical evidence-based algorithm. Out of the 3136 available articles as of August 8th, 2020, we selected 172 manuscripts that met inclusion criteria, which we subdivided into 5 main topics of discussion, being the various NAR techniques; patient factors (including patient selection, timing and ideal position); dressings; potential complications and finally, outcomes/patient satisfaction. Results: We found 92 articles describing NAR techniques, 41 addressing patient factors (out of which 17 discussed patient selection, 14 described ideal NAC location, 10 described appropriate timing), 10 comparing dressings, 7 studying NAR complications, and 22 addressing outcomes and patient satisfaction. We elaborated a comprehensive decision-making algorithm to help narrow down the choice among NAR techniques, and choose the correct strategy according to the various scenarios, and particularly the BR technique and skin envelope. Conclusions: No single NAR technique provides definitive results, which is why we believe there is no “end-all be-all solution”. NAR must be approached as a case-by-case situation. Furthermore, despite NAR being such a widely discussed topic in scientific literature, we still found a lack of clinical trials to allow for more thorough recommendations to be elaborated. Level of Evidence III: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/0026
Evaluation of coronary artery disease using technetium-99m-sestamibi first-pass and perfusion imaging with dipyridamole infusion.
Plasma concentrations of Tapentadol and clinical evaluations of a combination of Tapentadol plus Sevoflurane for surgical anaesthesia and analgesia in rabbits (Oryctolagus cuniculus) undergoing orchiectomy
Pain is probably under-treated in animals, particularly in rabbits, due to a lack of familiarity with the species and limited information about analgesic dose, efficacy and safety. Tapentadol (TAP) is a novel opioid drug, with a proven efficacy and safety profile in humans, which could be useful as an analgesic in rabbits. In a clinical study, TAP was administered (5 mg/kg, IV) to seven male New Zealand White rabbits 5 min before anaesthetic induction with sevoflurane to perform orchiectomy. Monitoring of vital signs, including heart rate, electrocardiogram, respiratory rate, invasive blood pressure, oxygen saturation, righting reflex, palpebral reflex, jaw tone and tongue retraction, was performed throughout surgery. Pain was assessed for 8 h following surgery, using previously validated parameters, physiological assessments and behavioural assessments. Blood was also collected at regular intervals to assess the pharmacokinetic profile of the drug. TAP was rapidly distributed and eliminated in rabbits. Apnoea did not occurred in any subject. Following surgery, there were very few observable signs of pain in four rabbits and all resumed normal activities within a few hours. In conclusion, this is the first study about the clinical effects and potential utility of TAP as an adjunct drug for anaesthesia and analgesia in the rabbit. However, further studies are still needed before its use in the veterinary clinical practice
Nucleon spin structure,topological susceptibility and the singlet axial vector coupling
The observed small value of the first moment of the polarized nucleon spin
structure function may be interpreted, in the Veneziano--Shore approach,
as a suppression of the first moment of the QCD topological
susceptibility. I give an extension of the Witten--Veneziano argument for the
problem, which yields the correction to the
relation (where is the axial
vector coupling).The correction, although negative, seems too small to account
for the data. I further argue that the
and decays indicate an enhancement rather than a suppression of
. A substantial gluon-like contribution in ,which could parallel a
similar one in the corresponding nucleon matrix element,is suggested.Comment: Latex 209,10 pages,no figure
Errors in neuroradiology
Approximately 4 % of radiologic interpretation in daily practice contains errors and discrepancies that should occur in 2-20 % of reports. Fortunately, most of them are minor degree errors, or if serious, are found and corrected with sufficient promptness; obviously, diagnostic errors become critical when misinterpretation or misidentification should significantly delay medical or surgical treatments. Errors can be summarized into four main categories: observer errors, errors in interpretation, failure to suggest the next appropriate procedure, failure to communicate in a timely and a clinically appropriate manner. Misdiagnosis/misinterpretation percentage should rise up in emergency setting and in the first moments of the learning curve, as in residency. Para-physiological and pathological pitfalls in neuroradiology include calcification and brain stones, pseudofractures, and enlargement of subarachnoid or epidural spaces, ventricular system abnormalities, vascular system abnormalities, intracranial lesions or pseudolesions, and finally neuroradiological emergencies. In order to minimize the possibility of error, it is important to be aware of various presentations of pathology, obtain clinical information, know current practice guidelines, review after interpreting a diagnostic study, suggest follow-up studies when appropriate, communicate significant abnormal findings appropriately and in a timely fashion directly with the treatment team
Evaluation of a questionnaire to detect the risk of developing ESGD or EGGD in horses
Equine gastric ulcer syndrome (EGUS) affects various categories of horses worldwide. This syndrome is now divided into two different diseases, based on the presence of lesions on either the squamous (Equine Squamous Gastric Disease, ESGD) or the glandular (Equine Glandular Gastric Disease, EGGD) mucosa. Diagnosis is based on the evaluation of the presence of gastric lesions with gastroscopic examination. As a gastroscopy can be considered expensive by clients, therapy is started often on the basis of clinical signs only. The aim of this study was to validate a questionnaire to detect the risk of developing ESGD or EGGD. The owners of 418 horses that were submitted to gastroscopic evaluation were asked to answer a questionnaire on risk factors for ESGD and EGGD. Horses were divided into three groups based on the results of the questionnaire and their risk of developing gastric lesions. In our population the survey was not useful to detect the presence and the severity of the lesions detected during gastroscopic examination, however answers to some of the questions did correlate with the development of gastric lesions. The questionnaire could therefore be a useful tool to evaluate the risk of ESGD or EGGD. Having owners periodically complete the survey could also make them more aware of changes in the conditions of the horses that could lead to gastric lesions. This could then help them seek advice from veterinarians on how to manage this potential ris
Effect of platelet lysate on human cells involved in different phases of wound healing
Background
Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization).
Methodology/Principal Findings
Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p<0.05 vs. control), comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points.
Conclusion/Significance
These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing
The chemical-physical knowledge before the restoration: The case of "The Plague in Lucca", a masterpiece of Lorenzo Viani (1882-1936)
Background: "The Plague in Lucca", a masterpiece of the contemporary painter Lorenzo Viani, was studied by multianalytical techniques (Multiband, IR and UV fluorescence imaging, micro-Raman spectroscopy, direct exposure-mass spectrometry, gas chromatography-mass spectrometry and energy dispersive X-ray fluorescence) in view of its restoration at the Gallery of Modern and Contemporary Art (GAMC) of Palazzo delle Muse in Viareggio (Lucca, Italy). The analysis allowed to obtain a better understanding of the artistic technique of the painter and to underline critical conservation aspects. Results: At first, non-invasive techniques, such as the Multiband Imaging, Infrared Reflectometry, UV Fluorescence and X-ray Fluorescence, have been applied in order to characterize the conservation state of the painting surface and determining the more representative zones of the painting for the taking of micro-samples to be analysed in the laboratory. The destructive chemical analysis of these micro-samples, performed using mass (DEMS and GC/MS) and infrared spectroscopy (micro-Raman), permitted to reveal the nature of the organic and inorganic materials present in the painting. Conclusions: The use of different physical and chemical diagnostic techniques allowed us to obtain precious information about the palette and the technique used by Lorenzo Viani for the realization of "La Peste a Lucca". Furthermore, this approach permit to characterize paintings, to understand the nature and origin of materials used by the artist and to develop the appropriate restoration procedure
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