In the present work an experimental program aimed at assessing the mechanical behavior of an innovative parabolic solar trough is presented. More specifically, a lightweight and low-cost collector ...making large use of adhesive joints, which can be easily assembled on-site, still performing at a high efficiency, was designed. Static and fatigue tests were performed on a full-scale prototype of the collector in the pre-production stage. The tests included differential torsion, concentrated and distributed bending, and distributed load (wind effect). During the tests, a network of strain gauges was placed in the most critical locations to measure the strain field, while laser sensors and cable transducers were placed in strategic positions to measure the displacements. The results demonstrate the strengths of the innovative parabolic trough collector and support the assessment of its structural integrity.
Background
Patients with hematological malignancies (HM) have a high risk of severe coronavirus disease 2019 (COVID‐19), also in the Omicron period.
Material and methods
Retrospective single‐center ...study including HM patients with severe acute respiratory syndrome Coronavirus 2 (SARS‐CoV2) infection from January 2022 to March 2023. Study outcomes were respiratory failure (RF), mechanical ventilation (MV), and COVID‐related mortality, comparing patients according to SARS‐CoV2 serology.
Results
Note that, 112 patients were included: 39% had negative SARS‐CoV2 serology. Seronegative were older (71.5 vs. 65.0 years, p = 0.04), had more often a lymphoid neoplasm (88.6% vs. 69.1%, p = 0.02), underwent anti‐CD20 therapy (50.0% vs. 30.9% p = 0.04) and had more frequently a severe disease (23.0% vs. 3.0%, p = 0.02) than seropositive.
Kaplan‐Meier showed a higher risk for seronegative patients for RF (p = 0.014), MV (p = 0.044), and COVID‐related mortality (p = 0.021). Negative SARS‐CoV2 serostatus resulted in a risk factor for RF (hazards ratio HR 2.19, 95% confidence interval CI 1.03–4.67, p = 0.04), MV (HR 3.37, 95% CI 1.06–10.68, p = 0.04), and COVID‐related mortality (HR 4.26, 95% CI 1.09–16.71, p = 0.04).
Conclusions
: HM patients with negative SARS‐CoV2 serology, despite vaccinations and previous infections, have worse clinical outcomes compared to seropositive patients in the Omicron era. The use of serology for SARS‐CoV2 diagnosis could be an easy tool to identify patients prone to developing complications.
Acute myeloid leukemia (AML) carrying inv(16)/t(16;16), resulting in fusion transcript CBFB-MYH11, belongs to the favorable-risk category. However, even if most patients obtain morphological complete ...remission after induction, approximately 30% of cases eventually relapse. While well-established clinical features and concomitant cytogenetic/molecular lesions have been recognized to be relevant to predict prognosis at disease onset, the independent prognostic impact of measurable residual disease (MRD) monitoring by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), mainly in predicting relapse, actually supersedes other prognostic factors. Although the ELN Working Party recently indicated that patients affected with CBFB-MYH11 AML should have MRD assessment at informative clinical timepoints, at least after two cycles of intensive chemotherapy and after the end of treatment, several controversies could be raised, especially on the frequency of subsequent serial monitoring, the most significant MRD thresholds (most commonly 0.1%) and on the best source to be analyzed, namely, bone marrow or peripheral blood samples. Moreover, persisting low-level MRD positivity at the end of treatment is relatively common and not predictive of relapse, provided that transcript levels remain stably below specific thresholds. Rising MRD levels suggestive of molecular relapse/progression should thus be confirmed in subsequent samples. Further prospective studies would be required to optimize post-remission monitoring and to define effective MRD-based therapeutic strategies.
In recent decades, the interest of the manufacturing industry towards additive manufacturing techniques has increased considerably. Speed and ease of implementation are just some of the factors that ...helped making this type of production one of the most developed in the world, considering also the possibility of creating complex geometries. The present research uses of a series of Al A357 specimens produced by SLM method. The experimental measurements on a first geometry have been used to calibrate the ductile damage model implemented in the FE code. The material model is based on both classical incremental model of plastic response with isotropic hardening and phenomenological concept of damage in continuum mechanic. The result of the calibration process was verified through the comparison of FE simulation of reticular specimens with the measured experimental response. Comparison between experimental data and numerical results will be discussed.
In this paper, modified Mohr Coulomb (MMC) and Lemaitre׳s damage model have been calibrated for a Ti–6Al–4V titanium alloy. A large uniaxial and multiaxial experimental program has been carried out ...on round, flat, smooth and notched, specimens. All experimental tests have been numerically reproduced adopting finite element models: most of the tests have been used to define the material parameters for the investigated damage models, exploiting an inverse method; some selected tests have been used to validate the calibrated damage criteria. Specifically, after the calibration stage, the capability of the material models to be transferred to a different and more critical scenario (high triaxiality and strain gradient) has been investigated by means of a three point bending test on a notched specimen. Moreover, in the paper, the advantages and drawbacks of Lemaitre׳s continuum damage mechanics (CDM) and MMC approaches have been addressed and discussed. Furthermore, a metallographic analysis using a scanning electron microscope (SEM) has been carried out and images of the specimen׳s fracture surface have been acquired in order to investigate the potential different fracture mechanisms, depending on the stress state.
•Modified Mohr Coulomb (MMC) and Lemaitre׳s damage model have been calibrated for a Ti–6Al–4V titanium alloy.•Uniaxial and multiaxial experimental program has been carried out on round, flat, smooth and notched, specimens.•The capability of the calibrated material models to be transferred to a different and more critical scenario has been investigated.•A metallographic analysis using a scanning electron microscope has been carried out on the specimen׳s fracture surface.
•Numerical simulation of fracture toughness test on Al6061-T6 specimen.•Geometry transferability of a ductile damage criterion in a high stress–strain gradient scenario.•Microstructure and fracture ...surface analysis.•Relation between optimum mesh size and microstructure.
Aim of the present paper is the evaluation of the capability of a ductile damage criterion to numerically predict (finite element model) the behaviour of Al6061-T6 compact specimen C(T) involved in fracture toughness tests. The parameters of the damage model have been previously calibrated with mono and multiaxial tests; the current work is an exploitation of such calibration in a different framework, in order to check its geometrical transferability even in a scenario dominated by a high strain gradient.
Finite element analysis has been carried out using the commercial finite element software ABAQUS 6.12 and a quasi-static explicit framework. The advantages and the possible drawbacks of the application of this kind of macroscopic failure criteria in a scenario dominated by very localized phenomena, thus involving material at grain size, are herein discussed. Due to the localized nature of the problem, mesh size potentially plays a relevant role in the failure, hence various mesh sizes have been analyzed and their performance is discussed on the basis of metallographic analyses.
Human cytomegalovirus (CMV) represents the most common viral infection after hematopoietic stem cell transplant (HSCT), mainly occurring as reactivation from latency in seropositive patients, with a ...different prevalence based on the extent and timing of seroconversion in a specific population. Here, we retrospectively analyzed a cohort of patients who underwent HSCT at our Institution between 2013 and 2018, all of whom were prophylactically treated with CMV‐IG (Megalotect Biotest®), to define the incidence and clinical outcomes of CMV reactivation and clinically significant infection. CMV infection occurred in 69% of our patient series, mainly resulting from reactivation, and CMV clinically significant infection (CS‐CMVi) occurred in 48% of prophylactically treated patients. CMV infection and CS‐CMVi impacted neither on relapse incidence nor on overall survival nor on relapse‐free survival. Moreover, a very low incidence of CMV end‐organ disease was documented. CMV‐IG used alone as prophylactic therapy after HSCT does not effectively prevent CMV reactivation.
Highlights
Prophylactic Cytomegalovirus‐specific immunoglobulins alone do not significantly decrease the risk of reactivation after hematopoietic stem cell transplant
Recommendations and guidelines for management of SARS-COV-2 infection in hematologic patients were developed in the very difficult context of dealing with novel viral variants from one pandemic wave ...to another, with different susceptibility to available drugs and vaccines. Moreover, the largest SARS-COV-2 case series in patients treated for hematologic malignancies, including stem cell transplant recipients, was published before the Omicron surge, and refers mainly to Alpha and Delta viral variants. These infections had very high mortality, in a period when antivirals and monoclonal antibodies were mostly unavailable. Here, we report for the first time a SARS-COV-2 Omicron variant outbreak inside a Bone Marrow Transplant (BMT) Unit, describing the characteristics, clinical course, and infection outcomes shortly before and shortly after myeloablative transplantation. We detail how infections were treated off-label and managed inside the BMT ward, to guarantee the best possible outcomes while avoiding risks for non-infected inpatients. The positive outcomes observed suggest that it may not be absolutely necessary to obtain SARS-CoV-2 PCR negativity before BMT in hematologic patients after treated infection, in cases with long-term PCR positivity and high-risk hematologic disease.
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