Laser beam welding of cast commercial pure titanium

In this work the joining by Laser Beam Welding (LBW) technique of commercial pure Titanium (CP Ti) cast specimens was carried out. The specimens considered for welding trials were cylindrical and flat (parallelepiped shape) ingots of little dimensions, as utilised in dentistry applications.The welds were investigated by optical and scanning electron microscopy (SEM) and by X-ray diffraction (XRD) measurements; mechanical properties were experimented by Vickers microhardness, across traverses through the welded sections, and by tensile tests, performed, for comparison, also on unwelded specimens in as cast condition; fractured surfaces after tensile tests were observed by SEM

Messa a punto di tecniche termografiche per il rilievo di difetti di fusione in getti di titanio commercialmente puro

Nel presente lavoro vengono riportati i risultati di uno studio sperimentale sull’applicazione di tecniche dimisura basate su termografia attiva per il rilievo di difettosità in provini di Ti commercialmente puro di grado2, realizzati mediante il metodo della fusione a cera persa. Le tecniche di termografia attiva ad infrarossimesse a punto hanno consentito di evidenziare la presenza di difetti sub-superficiali, non individuabiliattraverso i metodi convenzionali che utilizzano liquidi penetranti. In particolare sono state sperimentate siatecniche di termografia pulsata (“pulse phase”), basate sull’acquisizione delle mappe di temperaturasuperficiale dopo riscaldamento impulsivo dei provini, sia tecniche di termografia modulata (“lock-in”), basatesul rilievo delle mappe di temperatura durante l’applicazione di una sollecitazione termica sinusoidale. Laverifica dei risultati ottenuti con il metodo termografico è stata effettuata attraverso il confronto conosservazioni radiografiche a raggi ? e con indagini di tomografia rX computerizzata in 3D

Corrosion damage and periodic inspections on pressure devices and lifting equipments

This paper deals with requirements for service safety conditions of pressure devices and lifting equipments,according to the European and Italian Standards. Periodic controls and inspections are necessary to checkcorrosion damage and determine residual life, as showed for some significant case histories. As concern aspressure device, hydrogen induced cracking phenomena in steel walls of a demister, utilized to enhance the liquiddroplets removal in a vapor stream, were detected by ultrasound measurements. The measured defect sizeswere put in comparison with the required limits to verify if this device can be maintained in service. About liftingequipments, two different corrosion mechanisms were examined by detecting defects and measuring residualplate thickness: crevice, due to aggressive environment, at the interstitial of steel plates overlap in a welded andbolted joint of a gantry crane; lastly, crevice and corrosion fatigue of steel rail and plate in a double girder shipyardbridge crane, that was exposed for some decades to the daily aggressive action of direct solar radiation and seasalt, detrimental for the coating layer. In these two cases both defects size and plates thickness were consideredwith the aim of indicating treatments and restoration procedures of damaged components

Interior Regularity Estimates in High Conductivity Homogenization and Application

In this paper, uniform pointwise regularity estimates for the solutions of conductivity equations are obtained in a unit conductivity medium reinforced by a epsilon-periodic lattice of highly conducting thin rods. The estimates are derived only at a distance epsilon^{1+tau} (for some tau>0) away from the fibres. This distance constraint is rather sharp since the gradients of the solutions are shown to be unbounded locally in L^p as soon as p>2. One key ingredient is the derivation in dimension two of regularity estimates to the solutions of the equations deduced from a Fourier series expansion with respect to the fibres direction, and weighted by the high-contrast conductivity. The dependence on powers of epsilon of these two-dimensional estimates is shown to be sharp. The initial motivation for this work comes from imaging, and enhanced resolution phenomena observed experimentally in the presence of micro-structures. We use these regularity estimates to characterize the signature of low volume fraction heterogeneities in the fibred reinforced medium assuming that the heterogeneities stay at a distance epsilon^{1+tau} away from the fibres

Measuring changes in Schlemm’s canal and trabecular meshwork in different accommodation states in myopia children: an observational study

Abstract Purpose: Studies were designed to evaluate changes in the size of the Schlemm's Canal (SC) and trabecular meshwork(TM) during accommodation stimuli and cycloplegia states in myopic children. Methods: 34 children were enrolled. A -6D accommodation stimulus was achieved by looking at an optotype through a mirror. Cycloplegia state was induced with 1% tropicamide. Two states were confirmed by measuring the central lens thickness（CLT）, the anterior chamber depth and the pupil diameter. The size of the Schlemm's Canal (SC) and Trabecular Meshwork(TM) was measured using swept-source optical coherence tomography. And the associations between the change of the SC and the CLT were analyzed. Results: When compared with the relaxation state, under -6D accommodation stimuli, the size of SC increased significantly: the SC area (SCA) amplified from 6371±2517μm2 to 7824±2727 μm2; the SC length (SCL) from 249±10 μm to 295±12 μm, and SC width (SCW) from 27±9 μm to 31±8 μm. Under cycloplegia state, the SCA reduced to 5009±2028 μm2; the SCL to 212±μm and the SCW to 22±5 μm. In addition, the changed areas of SCA (r=0. 35; P=0.0007), SCL (r=0. 251; P=0.0172), and SCW (r=0. 253; P=0.016) were significantly correlated with the change in CLT. However, the size of TM did not change substantially when compared with the relaxation state. Only the TM length (TML) increased from 562±45μm to 587±47μm after -6D accommodation stimulus. Conclusion: SC size enlarges after -6D accommodation stimuli and shrinks under cycloplegia. However, for TM, only the TM length increase under accommodation stimulus state. KEYWORDS: Schlemm’s Canal, Trabecular Meshwork, accommodatio

The relationship between nurse managers' leadership style and patients' perception of the quality of the care provided by nurses: Cross sectional survey

Background:  In healthcare systems, human resources play a strategic role that has a significant impact on the whole caring process. When the wellbeing of professionals is low their performance decreases, counterproductive work behaviours may became more likely, and as a result the quality of care is compromised. Studies have shown that leadership style is particularly relevant in relation to the quality of work environments in healthcare organizations. Objective:  The main purpose of this study is to test a model that investigates the relationships between nurse managers’ leadership style and patients’ perception of the quality of the care provided by the nurses, through the mediation of the quality of the working environment (in terms of burnout, interpersonal strain and counterproductive work behaviour). Design:  A multi-centre cross-sectional study was conducted. Setting:  The study was conducted in five hospitals located two in the north, two in the centre and one in the south of Italy. Participants:  Participants were 479 registered nurses (working as staff nurses, while head nurses and nurse managers were excluded) and 829 patients aged 18 years or older, able to read and write Italian and hospitalized for at least 3 days. Severely ill or mentally disabled patients who were not able to fill in the questionnaire were excluded. Methods:  The data were collected through two different questionnaires, one for the nurses and one for the patients. A multilevel analysis was conducted to examine the hypothesized model. Results:  Results confirmed the hypothesis that, when nurses were satisfied with leadership, they felt less burned-out and strained in interpersonal relationships, they engaged less in misbehaviour, and, in turn, patients were more satisfied with the quality of the care provided by the nurses. Conclusions:  The results of this study showed that the characteristics of the organizational context, the leadership, and the behaviours of nurses, influenced patients’ perceptions of nurses’ care. Therefore, managers of healthcare services should take these results into account seriously in order to improve the quality of care provided to patients

COVID-19 infection in adult patients with hematological malignancies:a European Hematology Association Survey (EPICOVIDEHA)

Background: Patients with hematological malignancies (HM) are at high risk of mortality from SARS-CoV-2 disease 2019 (COVID-19). A better understanding of risk factors for adverse outcomes may improve clinical management in these patients. We therefore studied baseline characteristics of HM patients developing COVID-19 and analyzed predictors of mortality. Methods: The survey was supported by the Scientific Working Group Infection in Hematology of the European Hematology Association (EHA). Eligible for the analysis were adult patients with HM and laboratory-confirmed COVID-19 observed between March and December 2020. Results: The study sample includes 3801 cases, represented by lymphoproliferative (mainly non-Hodgkin lymphoma n = 1084, myeloma n = 684 and chronic lymphoid leukemia n = 474) and myeloproliferative malignancies (mainly acute myeloid leukemia n = 497 and myelodysplastic syndromes n = 279). Severe/critical COVID-19 was observed in 63.8% of patients (n = 2425). Overall, 2778 (73.1%) of the patients were hospitalized, 689 (18.1%) of whom were admitted to intensive care units (ICUs). Overall, 1185 patients (31.2%) died. The primary cause of death was COVID-19 in 688 patients (58.1%), HM in 173 patients (14.6%), and a combination of both COVID-19 and progressing HM in 155 patients (13.1%). Highest mortality was observed in acute myeloid leukemia (199/497, 40%) and myelodysplastic syndromes (118/279, 42.3%). The mortality rate significantly decreased between the first COVID-19 wave (March–May 2020) and the second wave (October–December 2020) (581/1427, 40.7% vs. 439/1773, 24.8%, p value < 0.0001). In the multivariable analysis, age, active malignancy, chronic cardiac disease, liver disease, renal impairment, smoking history, and ICU stay correlated with mortality. Acute myeloid leukemia was a higher mortality risk than lymphoproliferative diseases. Conclusions: This survey confirms that COVID-19 patients with HM are at high risk of lethal complications. However, improved COVID-19 prevention has reduced mortality despite an increase in the number of reported cases

COVID-19 infection in adult patients with hematological malignancies: a European Hematology Association Survey (EPICOVIDEHA)

Background: Patients with hematological malignancies (HM) are at high risk of mortality from SARS-CoV-2 disease 2019 (COVID-19). A better understanding of risk factors for adverse outcomes may improve clinical management in these patients. We therefore studied baseline characteristics of HM patients developing COVID-19 and analyzed predictors of mortality. Methods: The survey was supported by the Scientific Working Group Infection in Hematology of the European Hematology Association (EHA). Eligible for the analysis were adult patients with HM and laboratory-confirmed COVID-19 observed between March and December 2020. Results: The study sample includes 3801 cases, represented by lymphoproliferative (mainly non-Hodgkin lymphoma n = 1084, myeloma n = 684 and chronic lymphoid leukemia n = 474) and myeloproliferative malignancies (mainly acute myeloid leukemia n = 497 and myelodysplastic syndromes n = 279). Severe/critical COVID-19 was observed in 63.8% of patients (n = 2425). Overall, 2778 (73.1%) of the patients were hospitalized, 689 (18.1%) of whom were admitted to intensive care units (ICUs). Overall, 1185 patients (31.2%) died. The primary cause of death was COVID-19 in 688 patients (58.1%), HM in 173 patients (14.6%), and a combination of both COVID-19 and progressing HM in 155 patients (13.1%). Highest mortality was observed in acute myeloid leukemia (199/497, 40%) and myelodysplastic syndromes (118/279, 42.3%). The mortality rate significantly decreased between the first COVID-19 wave (March–May 2020) and the second wave (October–December 2020) (581/1427, 40.7% vs. 439/1773, 24.8%, p value < 0.0001). In the multivariable analysis, age, active malignancy, chronic cardiac disease, liver disease, renal impairment, smoking history, and ICU stay correlated with mortality. Acute myeloid leukemia was a higher mortality risk than lymphoproliferative diseases. Conclusions: This survey confirms that COVID-19 patients with HM are at high risk of lethal complications. However, improved COVID-19 prevention has reduced mortality despite an increase in the number of reported cases.EPICOVIDEHA has received funds from Optics COMMITTM (COVID-19 Unmet Medical Needs and Associated Research Extension) COVID-19 RFP program by GILEAD Science, United States (Project 2020-8223)