155 research outputs found

    Experimental tests on a dowel-type timber connection and validation of numerical models

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    This paper examines the dynamic behaviour of timber framed buildings under wind and dynamic loads, focusing on the role of connections being experimentally tested. The main aim of this manuscript is to analyze the in-service dynamic behaviour of a semi-rigid moment-resisting dowel-type connection between timber beam and column. For this purpose, two laboratory tests have been performed, the first on a connection and another one on a portal frame. The results are used to validate a numerical model of the simple portal frame, analyzed in OpenSees. The obtained relationships are also discussed and compared with Eurocode rules. The main result is that the joint stiffness is calculated through the Eurocode (EC) formulation underestimates the experimental one. A mutual agreement is obtained between the numerical model, validated from the experimental stiffness value for the connections, and the experimental results on the portal frame

    Death due to ingestion of nicotine-containing solution: Case report and review of the literature

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    Nicotine, a lipid-soluble alkaloid obtained from the dried leaves of Nicotiana, is most frequently encountered in tobacco products for smoking, chewing or sniffing as well as in a limited number of pesticides. Though nicotine is one of the most toxic drugs of abuse, it has rarely led to fatalities. Sudden death can be caused by cardiovascular arrest, respiratory muscle paralysis and/or central respiratory failure. A 42-year-old man was found dead by his wife. He was lying on the floor, next to a box containing many empty bottles of beer and vodka. Some labeled chemical bottles found at the scene contained various substances, including nicotine and brucine. Gross examination of the organs at autopsy revealed no specific findings. The toxicological examination failed to disclose any lethal toxic agents other than a high concentration of nicotine and its primary metabolite cotinine in femoral venous blood (2.2 μg/mL). Blood alcohol was determined to be 2.1 g/L in femoral venous blood. Only a paucity of fatal cases of nicotine poisoning has been reported in the literature so far. © 2009 Elsevier Ireland Ltd. All rights reserved

    Numerical Development of a Strengthened Wall-to-Diaphragm Seismic Connection: Calibration and Application on a Building Prototype

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    Effective wall-to-floor connections are crucial components of historical buildings to avoid dangerous mechanisms under seismic actions. Existing buildings often present poor friction-based links between timber floor and masonry wall and are not able to ensure the so called “box behavior”, necessary for the correct distribution of seismic forces. Nonlinear static analysis is one of the most common tools for the seismic assessment of unreinforced masonry buildings considering advanced nonlinear materials description and allowing for different approaches. The selection of a proper control node, for the definition of the pushover curve, is fundamental and sometimes controversial. Moreover, connections are modelled as simply fixed or absent at all. Dynamic nonlinear analysis seems preferable even suffering from a higher computational effort. On the bases of previous experimental campaign developed at the University of Minho, the pull out behavior of a strengthened and unstrengthened masonry-to-timber connection was simulated numerically using OpenSees software. The connection model considers strength degradation and pinching, in agreement with the experimental behavior, and is validated from the energetic point of view, suitable for being included in a global finite element model to study the influence of the hysteretic energy dissipated within the connections on the overall seismic response. This paper describes the calibration process and the application of the connection model into a unreinforced masonry prototype using nonlinear dynamic analysis under real seismic inputs. Both strengthened and unstrengthened configurations are implemented and results compared. The selected model is part of the blind prediction competition organised within the SERA-AIMS project involving the shaking table test of a half-scaled aggregate

    Simulation of blind pre-diction and post-diction shaking table tests on a masonry building aggregate using a continuum modelling approach

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    Masonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA-AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a post-diction phase, and proposes a series of simulation analyses including a strategy to shorten the actual records and save computation costs. The study was performed to investigate the extent of uncertainty in modelling for such masonry aggregates in relation to the experimental outcomes. Pre-diction results were proven to be not accurate in terms of predicted displacements and damage patterns. The upgrades introduced for the post-diction analyses, including the calibration of the elastic modulus and the introduction of a non-linear interface between the two units, allowed to improve the outcomes, with reasonable results in terms of predicted base shear force, displacements along Y-direction and damage pattern for the non-linear stage. The overall approach showed to be appropriate for the structural analysis of existing masonry aggregates, but the accurate modelling of this type of structure remains challenging due to the high level of uncertainties

    Influence of wall-to-floor connections and pounding on pre- and post-diction simulations of a masonry building aggregate tested on a shaking table

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    This paper presents numerical simulations within the frame of the project SERA-AIMS (Seismic Testing of Adjacent Interacting Masonry Structures). The study includes blind pre-diction and post-diction stages. The former was developed before performing the shaking table tests at the laboratory facilities of LNEC (Lisbon), while the latter was carried out once the test results were known. For both, three-dimensional finite element models were prepared following a macro-modelling approach. The structure consisted of a half-scaled masonry aggregate composed by two units with different floor levels. Material properties used for the pre-diction model were based on preliminary tests previously provided to the participants. The masonry constitutive model used for the pre-diction study reproduced classical stress-strain envelope, whereas a more refined model was adopted for the post-diction. After eigenvalue analysis, incremental nonlinear time history analysis was performed under a unique sequence based on the given load protocol to account for damage accumulation. In the post-diction, the numerical model was calibrated on the data recorded during the shaking table tests and nonlinear dynamic analysis repeated under the recorded accelerogram sequence. The interaction between the two units was simulated through interface elements. Moreover, the timber floors were accounted following different strategies: not modelling or considering nonlinear wall-to-floor connections. Advantages and disadvantages are then analysed, comparing the pre-diction and post-diction results with the experimental data. Numerical results differ from the experimental outcomes regarding displacements and interface pounding, although a clear improvement is visible in the post-diction model

    Handover checklist: testing a standardization process in an Italian hospital

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    Objectives: This study aimed to standardize and rationalize the handover, a critical and essential moment in common health care practices, through the realization of an efficient and standardized checklist, which could be used daily to ensure complete, thorough and effective handover. The principal purpose of the implementation of the handover is to reduce errors due to superficial and insufficient communication. Methods: The "operative group" defined the phases to the realization of the delineated aims: at first, the direct observation and the consequent realization of a handover checklist model and then, the experimental phases (trials). The handover checklist model was used for a month and it was daily and duly completed by the doctors who took part in the trial. To prove the success of the study, three questionnaires were distributed on different occasions. Results: Analyzing the answers to the questionnaires, the importance of the handover has come to light and that for the most part, the doctors consider it an essential and irreplaceable moment in daily health care work. Moreover, it became obvious that the use of the handover checklist guaranteed a considerable improvement in the traditional handover in terms of security, completeness, care continuity and clarity. The handover checklist was completely appreciated by the majority of the participant doctors who agree with the definitive introduction of it in their unit. Conclusions: Our study indicated the consistency of the handover checklist as an instrument to implement the handover and, indirectly, to improve the quality of the care

    From seaweeds to cosmeceutics: A multidisciplinar approach

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    Macroalgae are widespread on the coasts of all the globe and lead to a negative ecological impact, requiring expensive remediations. Therefore, the valorization of invasive seaweed as a renewable source of bioactive products could represent a valid solution. In this context, three algal biomasses, belonging to brown, green, and red families (Sargassum muticum, Ulva lactuca, Solieria filiformis), collected in the venetian Laguna, were investigated as a source of active compounds for the formulation of cosmeceutics. Microwave (MW) and ultrasound (US) were applied to enhance the algae extraction by means of a hydroalcoholic solution. According to total phenolic content (TPC) evaluation, MW demonstrated the best performing outcomes, resulting in 19.77, 22.02, and 16.94 mgGAE/gExtr (30 min at 90â—¦C) for brown, green, and red algae, respectively. Antioxidant activity was tested as well, showing comparable trends (49.19, 26.24, and 3.02 mmolTrolox eq./gExtr for brown, green, and red algae, respectively). Due to natural algae predisposition to absorb contaminants, the metal content analysis helped to screen the applicability of these extracts, identifying Ulva lactuca as the most suitable source of antioxidants for cosmetic formulations. This MW extract was then adopted to formulate two different preparations, namely a gel and an emulsion. Thermal and mechanical tests confirmed the stability of each formulation, together with neutral organoleptic characteristics. Finally, the actives release was investigated by means of a tape stripping essay, showing an efficient controlled release for gel formulation, even after 7 h of test. The produced cosmeceutics merged non-conventional extraction technologies with formulation expertise, offering a valuable alternative to solve the macroalgae disposal issue

    Child abuse and dental neglect: the dental team's role in identification and prevention

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    Health, education and social services are placing increasing emphasis on preventing abuse and neglect by early intervention to support families where children and young people may be at risk. Dental hygienist and dental assistants, like all other health professionals, can have a part in recognizing and preventing children from those who would cause them harm. They should be aware of the warning signs, recognizing what to consider as abuse or dental neglect and know how to deal with these young patients, and to fulfil their legal and ethical obligation to report suspected cases. The purpose of this report is to review the oral and dental aspects of child abuse and dental neglect thus helping the dental team in detecting such conditions. In particular, this report addresses the evaluation of bite marks as well as perioral and intraoral injuries, infections, early childhood caries and diseases that may be indicative of child abuse or neglect. Emphasis is placed on an appropriate protocol to follow in the dental practice to best treat and protect children who may have suffered abuse, helping the team in the diagnosis and documentation

    Role of biomechanical assessment in rotator cuff tear repair: Arthroscopic vs mini-open approach

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    BACKGROUND Rotator cuff (RC) tears are one of the most frequent pathologies within the shoulder girdle. Hand dominance and older age are associated with RC tears. Two different surgical procedures, the mini-open (MO) and all-arthroscopic (AA) approach, represented the standard of treatment. AIM To compare the clinical and biomechanical outcomes of two surgical techniques (AA vs MO procedure) performed to address the painful shoulder syndrome with partial or total supraspinatus tendon tear. METHODS Eighty-eight participants, 50 following RC repair with AA and 38 with MO approach, were recruited in the present cross-sectional case-control study (ORTHO-SHOULDER, Prot. 0054602). All patients underwent postoperative clinical evaluation for pain (Visual analogic scale), impairment, and disability (disability of the arm, shoulder, and hand) and limitation in daily activity (Constant-Murley score). Patients\u2019 shoulder mobility was also assessed in our Laboratory of Functional Movement through a wearable inertial sensor and surface electromyography to monitor kinematics and muscle activity during the movement on the frontal (abduction/adduction) and sagittal (flexion-extension) planes. RESULTS No statistically significant differences between the two procedures were observed in either main clinical score or range of motion. A significant increase in velocity during the movement execution and a higher contribution of upper trapezius muscles were found in the AA group compared with MO patients. CONCLUSION In terms of clinical scores, our findings were in line with previous results. However, the use of technology-based assessment of shoulder mobility has revealed significant differences between the two techniques in terms of mean velocity and pattern of muscle activation

    Cranio-Mandibular Disorders after Whiplash Injury: A Mono-Institutional Clinical Study on 31 Patients

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    Background: Whiplash is a consequence of traumatic injuries, mostly related to road accidents, with variable clinical manifestations, also known as Whiplash Associated Disorders, such as neck, head and temporo-cranio-mandibular pain. Methods: The current study aims to evaluate the onset and evolution of temporomandibular joint pain in people with whiplash in a study group treated with the use of Zimmer Collars (adjustable rigid cervical collars for neck immobilization), as compared to a control group. This prospective study included 31 patients followed by the Dental Prosthesis Department of the University of Bari “Aldo Moro”: 20 patients with whiplash (age range: 20–39 years) treated with Zimmer collars and 11 patients with whiplash (age range: 20–33 years) who were not. Immediately after the whiplash occurred, a visual analogue scale (VAS) was used to describe the intensity of pain and to complete the chart of the European Academy of Craniomandibular Disorders. Five out of twenty patients, already treated with a Zimmer collar, wore an occlusal splint as well because of persistent pain reported at the 28-day and 60-day follow-up and were supported by pharmacological therapy with analgesics (paracetamol) and muscle relaxants (thiocolchicoside). Results: During the last follow-up (at six months), three out of five patients displayed a residual VAS score of 3, 4, and 5, respectively, while the remaining two displayed a VAS of 0. In the control group, four out of eleven patients needed to wear an occlusal splint but without muscle relaxants and analgesics pharmacological therapy; these four corresponded to the patients showing a residual painful symptomatology, with VAS reaching value of 2, and also were the oldest patients of the group. Data regarding VAS values and Zimmer collar use, both at the first visit and six months later, were statistically analyzed. Conclusion: Our prospective study highlights how whiplash-associated acute disorders are often self-limiting over a period of few months, thus reducing the possibility of symptom chronicity; the latter seems to be strictly related to lesion severity, pre-existence of a craniomandibular dysfunction and patient age, but appears to be independent from Zimmer collar use, as statistically confirmed
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