274 research outputs found

    Analytical Design Concept for Synchronous Reluctance Machines

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    The aim of the thesis is to derive an analytical design concept based on mathematical and physical model of synchronous reluctance machines working principles. The design concept general validity allows to adopt it for any application specifications and requirements. Magnetic, electrical and mechanical aspects are investigated to maximize the motor performances in high torque density and efficiency terms.ope

    Vascular Endograft Infection with Listeria monocytogenes reated with Surgical Debridement but without Graft Removal

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    The awareness of Listeria monocytogenes as a pathogen in meningitis and bacteremia in immunosuppressed patients is high. We report a case of vascular graft infection due to Listeria monocytogenes as an example of a less well-known manifestation of listeriosis and focus on the possible treatment procedures emphasizing a management with surgical debridement but preservation of the endograft, in contrast to the gold standard treatment of vascular graft infections which consists of a removal of the graft

    Visualization of SpoVAEa Protein Dynamics in Dormant Spores of <i>Bacillus cereus</i> and Dynamic Changes in Their Germinosomes and SpoVAEa during Germination

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    Bacillus cereus spores, like most Bacillus spores, can survive for years and germinate when their surroundings become suitable, and germination proteins play an important role in the initiation of germination. Because germinated spores lose the extreme resistance of dormant spores, information on the function of germination proteins could be useful in developing new strategies to control B. cereus spores. Prior work has shown that (i) the channel protein SpoVAEa exhibits high-frequency movement in the outer leaflet of the inner membrane (IM) in dormant B. subtilis spores and (ii) the formation of the foci termed germinosomes between two germination proteins, the germinant receptor GerR and the scaffold protein GerD, in developing B. cereus spores is slower than foci formation by GerR and GerD individually. However, the movement dynamics of SpoVAEa in B. cereus spores, and the behavior of the germinosome upon B. cereus spore germination, are not known. In this study, we found that SpoVAEa fluorescent foci in dormant B. cereus spores move on the IM, but slower than in B. subtilis spores, and they likely co-localize transiently with GerD-mScarlet-I in the germinosome. Our results further indicate that (i) the expression of GerR-SGFP2 and SpoVAEa-SGFP2 with GerD-mScarlet-I from a plasmid leads to more heterogeneity and lower efficiency of spore germination in B. cereus, and (ii) germinosome foci observed by Fluorescence resonance energy transfer (FRET) between GerR-SGFP2 and GerD-mScarlet-I can be lost soon after the spore-phase transition. However, this is not always the case, as some GerR-SGFP2 and GerD-mScarlet-I foci continued to exist, co-localize, and even show a weak FRET signal. These data highlight the heterogeneous behavior of spore germination protein complexes and indicate that some complexes may persist beyond the initiation of germination. IMPORTANCE Bacillus cereus is commonly present in soil and infects humans via contaminated food. In this study, we used B. cereus spores to investigate the movement of the spore-specific inner membrane (IM) channel protein SpoVAEa, the interaction between SpoVAEa and the germinosome scaffold protein GerD, and the dynamics of germinosomes with GerR and GerD in spore germination. Our results expand upon observations of interactions between specific B. cereus spore germination proteins, in particular the GerR germinant receptor A, B, and C subunits and GerD, as well as those between SpoVAEa and GerD. The approaches used in this work could also be used to examine the interactions between GerD and SpoVAEa and other germination proteins in spores of other Bacillus species

    Cross Laminated Timber (CLT) Beams Loaded in Plane: Testing Stiffness and Shear Strength

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    Cross Laminated Timber (CLT) is a relatively new timber product used in constructions that gained lots of popularity over the last decade. The product itself is constituted by multiple glued layers of juxtaposed boards, usually arranged in an opposite direction between one layer and the adjacent ones. This particular structure brings several benefits, i.e. the possibility to use the same product both for walls and slabs, since it can bear in plane and out of plane loads. However, the mechanical behavior differs from usual timber products, and research is still ongoing to achieve common agreement on standard procedures for testing and theories for evaluating stresses for safety verifications. This paper proposes to investigate the behavior of CLT beams loaded in plane by testing several specimen with a four point bending test setup according to the EN 408 procedure \cite{EN408}. The main goal is to analyze the shear behavior of these beams hence the particular geometry is specifically chosen to obtain in plane shear failure. First the matter is analyzed by a literature review to study the existing theories for the calculation of in plan shear stresses in CLT elements. Then the experimental campaign is reported, the first part regarding elastic range test for Modulus of Elasticity measurement and the second main part regarding the failure tests to investigate shear behavior with regard to different mechanisms. Last conclusions are made and results are compared with other existing tests and proposed values in literature

    "Growing through relationship" - the Engagement of the Health Professional Students in the Internship Experience: a Grounded Theory Research

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    BACKGROUND AND AIM: Little is known about the students' engagement in the training experience and how it is lived by the health professional students. We aim at building a theoretical model of the engagement process starting from their lived experiences with Grounded Theory approach. METHODS: In-depth qualitative interviews are conducted with 12 students from the Master Degree Courses in Nursing, Physiotherapy and Prevention Techniques in the environment and in the workplace, who had carried out and/or were doing internships in the same territory (2nd and 3rd year). Results The health professions' student engagement in the training program is developed in three main phases: initial phase, central phase and final phase, where emotions, behaviours, awareness contribute to the development of the entire engagement process with different relevance. The intertwining of these different components that develop along the stages of the experience gives life to the core category: growing through relationship, which expressed the crucial role of the relational network built during the internship experience in shaping students' engagement. CONCLUSIONS: The results of this study underline the crucial role of students' engagement in the internship experience in favouring both better learning outcomes and perspective professional success and wellbeing. (www.actabiomedica.it)

    Hyperlactatemia and Antiretroviral Therapy: The Swiss HIV Cohort Study

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    The prevalence, clinical presentation, and risk factors for hyperlactatemia among patients receiving antiretroviral therapy was determined during a 1-month period for patients in the Swiss HIV Cohort Study. Overall, 73 (8.3%) of 880 patients presented an increase in serum lactate of >1.1 times the upper normal limit (UNL). For 9 patients (1%), lactate elevation was moderate or severe (>2.2 times the UNL). Patients who presented with hyperlactatemia were more likely to be receiving stavudine with or without didanosine (odds ratio, 2.7; 95% confidence interval, 1.5-4.8), as compared with patients who received zidovudine-based regimens. The risk increased with increasing time receiving stavudine with or without didanosine. The association between hyperlactatemia and stavudine with or without didanosine was not biased by these medications being more recently available and, therefore, being given preferentially to patients who had prolonged use of nucleoside analog reverse-transcriptase inhibitors. Hyperlactatemia was associated with lipoatrophy, hyperlipidemia, and hyperglycemia. Age, sex, or stage of infection with human immunodeficiency virus were not predictive of hyperlactatemia. Determination of lactate levels may prove useful in the screening for mitochondrial toxicit

    Bacteremia During the First Year After Solid Organ Transplantation: An Epidemiological Update.

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    BACKGROUND There are limited contemporary data on the epidemiology and outcomes of bacteremia in solid organ transplant recipients (SOTr). METHODS Using the Swiss Transplant Cohort Study registry from 2008 to 2019, we performed a retrospective nested multicenter cohort study to describe the epidemiology of bacteremia in SOTr during the first year post-transplant. RESULTS Of 4383 patients, 415 (9.5%) with 557 cases of bacteremia due to 627 pathogens were identified. One-year incidence was 9.5%, 12.8%, 11.4%, 9.8%, 8.3%, and 5.9% for all, heart, liver, lung, kidney, and kidney-pancreas SOTr, respectively (P = .003). Incidence decreased during the study period (hazard ratio, 0.66; P < .001). One-year incidence due to gram-negative bacilli (GNB), gram-positive cocci (GPC), and gram-positive bacilli (GPB) was 5.62%, 2.81%, and 0.23%, respectively. Seven (of 28, 25%) Staphylococcus aureus isolates were methicillin-resistant, 2/67 (3%) enterococci were vancomycin-resistant, and 32/250 (12.8%) GNB produced extended-spectrum beta-lactamases. Risk factors for bacteremia within 1 year post-transplant included age, diabetes, cardiopulmonary diseases, surgical/medical post-transplant complications, rejection, and fungal infections. Predictors for bacteremia during the first 30 days post-transplant included surgical post-transplant complications, rejection, deceased donor, and liver and lung transplantation. Transplantation in 2014-2019, CMV donor-negative/recipient-negative serology, and cotrimoxazole Pneumocystis prophylaxis were protective against bacteremia. Thirty-day mortality in SOTr with bacteremia was 3% and did not differ by SOT type. CONCLUSIONS Almost 1/10 SOTr may develop bacteremia during the first year post-transplant associated with low mortality. Lower bacteremia rates have been observed since 2014 and in patients receiving cotrimoxazole prophylaxis. Variabilities in incidence, timing, and pathogen of bacteremia across different SOT types may be used to tailor prophylactic and clinical approaches

    Distribution of Aspergillus Species and Prevalence of Azole Resistance in Respiratory Samples From Swiss Tertiary Care Hospitals

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    Among 400 Aspergillus species from respiratory samples in Switzerland, Aspergillus fumigatus was the most frequent species. Non-fumigatus Aspergillus spp were more prevalent among solid organ transplant recipients and after azole exposure. Azole resistance was detected in 4 A fumigatus isolates, 3 of them with the "environmental" mutation TR34_{34}/L98H in the cyp51A gene

    Impact of different urinary tract infection phenotypes within the first year post-transplant on renal allograft outcomes.

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    In this study we investigated the clinical impact of different urinary tract infection (UTI) phenotypes occurring within the first year after renal transplantation. The population included 2368 transplantations having 2363 UTI events. Patients were categorized into four groups based on their compiled UTI events observed within the first year after transplantation: (i) no colonization or UTI [n=1404; 59%], (ii) colonization only [n=353; 15%], (iii) occasional UTI with 1-2 episodes [n=456; 19%], and (iv) recurrent UTI with ≥3 episodes [n=155; 7%]. One-year mortality and graft loss rate were not different among the four groups, but patients with recurrent UTI had a 7-10ml/min lower eGFR at one year (44ml/min vs 54, 53 and 51ml/min; p<0.001). UTI phenotypes had no impact on long-term patient survival (p=0.33). However, patients with recurrent UTI demonstrated a 10% lower long-term death-censored allograft survival (p<0.001). Furthermore, recurrent UTI was a strong and independent risk factor for reduced death-censored allograft survival in a multivariable analysis (HR 4.41, 95% CI 2.53-7.68, p<0.001). We conclude that colonization and occasional UTI have no impact on pertinent outcomes, but recurrent UTI are associated with lower one-year eGFR and lower long-term death-censored allograft survival. Better strategies to prevent and treat recurrent UTI are needed

    Epidemiology and outcomes of medically attended and microbiologically confirmed bacterial foodborne infections in solid organ transplant recipients

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    Food-safety measures are recommended to solid organ transplant (SOT) recipients. However, the burden of foodborne infections in SOT recipients has not been established. We describe the epidemiology and outcomes of bacterial foodborne infections in a nationwide cohort including 4405 SOT recipients in Switzerland between 2008 and 2018. Participants were prospectively followed for a median of 4.2 years with systematic collection of data on infections, and patient and graft-related outcomes. We identified 151 episodes of microbiologically confirmed bacterial foodborne infections occurring in median 1.6 years (IQR 0.58-3.40) after transplantation (131 [88%] Campylobacter spp. and 15 [10%] non-typhoidal Salmonella). The cumulative incidence of bacterial foodborne infections was 4% (95% CI 3.4-4.8). Standardized incidence rates were 7.4 (95% CI 6.2-8.7) and 4.6 (95% CI 2.6-7.5) for Campylobacter and Salmonella infections, respectively. Invasive infection was more common with Salmonella (33.3% [5/15]) compared to Campylobacter (3.2% [4/125]; p = .001). Hospital and ICU admission rates were 47.7% (69/145) and 4.1% (6/145), respectively. A composite endpoint of acute rejection, graft loss, or death occurred within 30 days in 3.3% (5/151) of cases. In conclusion, in our cohort bacterial foodborne infections were late post-transplant infections and were associated with significant morbidity, supporting the need for implementation of food-safety recommendations
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