62 research outputs found

    Design and experimental assessment of a novel damper with high endurance to seismic loads

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    The study presents the design and the experimental characterization of a new energy dissipation device aimed at providing improved resistance to repeated seismic loads. Differently from conventional steel hysteretic dampers, which dissipate energy by yielding of a mild steel core and are noted to suffer low-cycle fatigue, the new damper provides energy dissipation by the friction that is activated between a moving shaft and a lead core prestressed within a tube. The prestress level is controlled during the assembling process, allowing to adjust the axial strength of the damper. Thanks to the ability of lead to restore its properties by static recrystallization taking place immediately after deformation, repeated cycles of loading do not produce damages that may accrue and eventually lead to failure of the device. Moreover, prestressing of the lead core allows to achieve high specific strength (i.e., high force to volume ratio), thereby providing low dimensions which help to reduce the architectural invasiveness. Prototypes of the damper were subjected to the test procedure established in the European standard EN 15129 for Displacement Dependent Devices, fulfilling the relevant requirements. The damper provides a robust and stable response over repeated cycles, characterized by essentially rectangular hysteresis loops with an equivalent viscous damping ratio ξeff of about 55%. Moreover, it shows low sensitivity of mechanical properties on the loading rate and the ability to withstand multiple cycles of motion at the design earthquake displacement without deterioration of performance, demonstrating maintenance-free operation in presence of repeated ground shakes. Its ability to survive several strong motions without being damaged, and its high damping capability coupled to a compact design and low manufacturing cost, are the distinctive features that make it suitable for social housing

    Recreational Drug Misuse and Its Potential Contribution to Male Fertility Levels’ Decline: A Narrative Review

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    Recreational drug intake may be associated with a range of medical untoward consequences, including male infertility. However, as the related evidence is still limited, the main outcome of this review is to provide a better understanding of the existence of any association between recreational drug misuse and male fertility levels’ decline. Whilst searching the MEDLINE/PubMed, a comprehensive overview of the literature regarding male infertility and substances of abuse (e.g., phytocannabinoids, opiates/opioids, stimulants, ‘herbal highs’, psychedelics, and ‘novel psychoactive substances) was here undertaken. Due to the paucity of robust, high-quality, empirical, human studies, a narrative strategy was here preferred over a systematic approach. Relevant data are qualitatively analyzed and presented in a table. Although most available evidence is in support of a detrimental role of cannabis on human spermatogenesis, a few remaining studies failed to document any effect of this drug on seminal quality, and it is not clear to which extent this drug impacts fertility rates/time to pregnancy. The current understanding of the impact of opiate-, cocaine- and amphetamine/stimulant-misuse on human reproduction is widely unknown, and most studies dealing with this matter represent only an extrapolation of data derived from specific clinical circumstances. Although the message of ‘no smoking, no alcohol and no street drugs’ should always be offered as good health advice to all patients seeking medical help for fertility issues, robust scientific clinical evidence in support of a direct detrimental impact of recreational drugs on spermatogenesis is scant to date

    Misuse of Anticholinergic Medications: A Systematic Review

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    (1) Background: Over the last decade, misuse and diversion of medications has appeared to be increasingly concerning phenomena, including a range of different molecules. As current knowledge on the abuse of centrally acting anticholinergics is limited, the aim of the present study is to review the relevant published data, focusing on the following molecules: benztropine, biperiden, scopolamine, orphenadrine, and benzhexol/trihexyphenidyl (THP). (2) Methods: A systematic literature review was carried out using Pubmed, Scopus, and Web of Science databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Research methods were registered on PROSPERO (CRD42021257293). (3) Results: A total of 48 articles, including case reports, surveys, and retrospective case series analyses, were included. Most articles focused on benzhexol/THP (n = 25), and benztropine (n = 4). The routes of administration were mostly oral, and macrodoses together concomitant illicit drugs, e.g., cocaine, have been recorded. Toxidromes included both physical (e.g., tachycardia, tachypnoea, dilatated pupils, dry skin, urinary retention, ataxia, etc.) and psychiatric symptoms (e.g., anxiety, agitation, delirium, etc.). Fatal outcomes were very rare but reported. (4) Conclusion: Results from the present study show that anticholinergic misusing issues are both widespread worldwide and popular. Considering the potential adverse effects associated, healthcare professionals should be vigilant and monitor eventual misusing issues

    The association between insight and depressive symptoms in schizophrenia: Undirected and Bayesian network analyses

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    Background. Greater levels of insight may be linked with depressive symptoms among patients with schizophrenia, however, it would be useful to characterize this association at symptom-level, in order to inform research on interventions. Methods. Data on depressive symptoms (Calgary Depression Scale for Schizophrenia) and insight (G12 item from the Positive and Negative Syndrome Scale) were obtained from 921 community-dwelling, clinically-stable individuals with a DSM-IV diagnosis of schizophrenia, recruited in a nationwide multicenter study. Network analysis was used to explore the most relevant connections between insight and depressive symptoms, including potential confounders in the model (neurocognitive and social-cognitive functioning, positive, negative and disorganization symptoms, extrapyramidal symptoms, hostility, internalized stigma, and perceived discrimination). Bayesian network analysis was used to estimate a directed acyclic graph (DAG) while investigating the most likely direction of the putative causal association between insight and depression. Results. After adjusting for confounders, better levels of insight were associated with greater self-depreciation, pathological guilt, morning depression and suicidal ideation. No difference in global network structure was detected for socioeconomic status, service engagement or illness severity. The DAG confirmed the presence of an association between greater insight and self-depreciation, suggesting the more probable causal direction was from insight to depressive symptoms. Conclusions. In schizophrenia, better levels of insight may cause self-depreciation and, possibly, other depressive symptoms. Person-centered and narrative psychotherapeutic approaches may be particularly fit to improve patient insight without dampening self-esteem

    Transcranial electrical and magnetic stimulation (tES and TMS) for addiction medicine: A consensus paper on the present state of the science and the road ahead

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    There is growing interest in non-invasive brain stimulation (NIBS) as a novel treatment option for substance-use disorders (SUDs). Recent momentum stems from a foundation of preclinical neuroscience demonstrating links between neural circuits and drug consuming behavior, as well as recent FDA-approval of NIBS treatments for mental health disorders that share overlapping pathology with SUDs. As with any emerging field, enthusiasm must be tempered by reason; lessons learned from the past should be prudently applied to future therapies. Here, an international ensemble of experts provides an overview of the state of transcranial-electrical (tES) and transcranial-magnetic (TMS) stimulation applied in SUDs. This consensus paper provides a systematic literature review on published data – emphasizing the heterogeneity of methods and outcome measures while suggesting strategies to help bridge knowledge gaps. The goal of this effort is to provide the community with guidelines for best practices in tES/TMS SUD research. We hope this will accelerate the speed at which the community translates basic neuroscience into advanced neuromodulation tools for clinical practice in addiction medicine

    DESIGN, TESTING AND MODELING OF A NOVEL FRICTION DAMPER WITH ENHANCED RESISTANCE TO REPEATED SEISMIC LOADS

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    The study presents the design, experimental characterization and modeling of a novel friction damper with enhanced resistance to repeated seismic loads. This device provides energy dissipation by the friction force triggered between a moving shaft and a lead core prestressed within a rigid steel chamber. As there are not mechanical parts that are subjected to cyclic stresses, there is no risk of fatigue and the damper is expected to resist to a virtually unlimited number of load cycles. Two prototypes of the friction damper were tested according to the procedure established in the European standard EN 15129 for Displacement Dependent Devices, fulfilling the relevant requirements. The damper provides a stable response over repeated cycles, characterized by an essentially rectangular hysteresis loop with an equivalent viscous damping ratio ?eff of more than 55%. Moreover, the damper is characterized by a low sensitivity to the loading rate and by the ability to withstand multiple cycles of motion at the design earthquake displacement without deterioration of performance, providing maintenance-free operation in presence of repeated ground shakes. A 3D finite element model of the friction damper is formulated in Abaqus and validated upon the results of the experimental tests. The model is then used in a parametric study to investigate the influence of the diameters of the shaft on the output force. The numerical data points are fitted by a simple model which can be used for designing the damper according to a specific quasi-static force
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