Productivity Enhancement in Directed Energy Deposition: The Oscillating Scanning Strategy Approach

Directed Energy Deposition (DED) is an additive manufacturing process that enables the production of large metal components by melting the feedstock material while being deposited. An improvement of the production speed of this process would further increase its applicability in many industrial fields. The DED building rate is strictly related to the building parameters adopted, in particular to the laser spot diameter, which also affects the build accuracy and the surface quality of the components. The possibility of using a variable laser spot would result in a significant increase in the production rate in bulky zones, while also providing a good surface quality where needed. In the present work, an oscillating scanning strategy was used to create a large apparent laser spot (+ 170% of the nominal value) to produce 316L stainless steel samples via DED. The optimisation of the DED parameters with the oscillating strategy was performed using the single scan tracks (SSTs) approach. The morphologies of the SSTs obtained with different process parameters were assessed and the geometrical features related to the melt pools were analysed in order to select the most suitable X and Z displacements for the production of the cubic samples. The analyses of the cubes revealed that, if the correct overlap among nearby scans is selected, it is possible to obtain dense samples with all the oscillating diameters tested. Finally, comparing the building rate and powder efficiency values confirmed that this method can accelerate the building process and improve its overall performance

Haemato-oncology and burnout: an Italian survey

This cross-sectional survey aimed to evaluate the prevalence of burnout and estimated psychiatric disorders among haemato-oncology healthcare professionals in Italy. The aspects of work that respondents perceive as stressful and satisfying have also been examined. The assessments were made using the Maslach Burnout Inventory (MBI), General Health Questionnaire and a study-specific questionnaire. Logistic regression models were applied to show associations between different sources of work-related stress and burnout. Three hundred and eighty-seven out of 440 (87.95%) returned their questionnaires. The scores on MBI subscales indicate a high level of emotional exhaustion in 32.2% of the physicians and 31.9% of the nurses; a high level of Depersonalisation in 29.8 and 23.6%, respectively; and a low level of personal accomplishment in 12.4 and 15.3% respectively. The estimated prevalence of psychiatric disorders was 36.4% in physicians and 28.8% in nurses. Statistical analysis confirmed age, sex, personal dissatisfaction, physical tiredness and working with demanding patients to be associated with burnout. In conclusion, haemato-oncology healthcare professionals report a level of burnout and estimated psychiatric morbidity comparable to other oncological areas. Knowledge of the mechanisms of burnout and preventing and dealing with them is therefore a fundamental requirement for the improvement of quality in health services and job satisfaction

Optimization of Process Parameters for CuCrZr Alloy Manufactured by Electron Beam Powder Bed Fusion Technology

The CuCrZr alloys exhibit advantageous mechanical properties and high electrical conductivity which make them promising for many applications in the electrical and aerospace engineering industries, e.g. in the manufacture of vacuum electronics and fusion energy research. Unfortunately, these two advantageous properties are in opposition to each other, i.e., the increase of hardness, is associated to a decrease of electrical conductivity. Additive manufacturing technologies are good candidates to balance these two aspects to achieve high performance parts. Powder-Bed-Fusion (PBF) techniques, in fact, involve rapid heating and cooling rates which allow to obtain huge microstructural refinements, thereby improving the mechanical properties without any significant loss in electrical conductivity. This study concerns the process parameter optimization for CuCrZr alloys produced using Electron-Beam-PBF technology using a trial-and-error approach. Material was characterized by porosity analysis, tensile and electrical conductivity measurements. The effect of process parameters on microstructure and densification behavior was also investigated

Gastrectomia mini-invasiva robotica: fasi tecniche e vantaggi dell’approccio robotico

Aim of the study. To show the technical steps and advantages of robotic total/subtotal gastrectomy. Material & Methods. Between 2000 and 2009, 96 robotic gastric resections have been performed: 45 total gastrectomies, 48 subtotal gastrectomies and 3 partial resections. Patient is in supine position, with 10°-15° reverse-Trendelemburg. Five ports are placed in half concave line. Preliminary exploration, gastro-colic detachment and short gastric vessels section are performed in traditional laparoscopy. The robotic cart is then installed. Infra-pyloric lymphadenectomy and right gastroepiploic vessels section is completed before the transection of the duodenum with a linear endostapler. Lymphadenectomy is performed in a clockwise fashion along the hepatic proper, common hepatic, celiac trunk and splenic artery. The right gastric artery, the left gastric artery and vein are sectioned in the process. In total gastrectomy the distal oesophagus is mobilized after lymphadenectomy of pericardial stations and sectioned, then an anastomosis by circular stapler was performed. After subtotal gastrectomy, the gastro-intestinal anastomosis is performed by stapler or robotic hand-suturing. The specimen is retrieved through a mini-laparotomy in the right flank. Results. Average intra-operative time was 280 min (range:120-480). Conversion was necessary in eight patients: 2 cases to laparoscopy (one splenic injury, one robotic arm failure), 6 cases to open surgery (locally advanced or metastatic disease). The mean number of removed nodes in D2 was 32.2 (range 19-70). Postoperative morbidity and mortality were respectively 19.8% and 3.1%. Anastomotic and duodenal stump leakage occurred respectively in 11 and 3 cases (11.4% and 3.1%). A redo-surgery was necessary in 7 patients (7.3%). Mean postoperative hospital stay was 11.6 days.Conclusion. Robotic total/subtotal gastrectomy is a feasible, safe and oncologically adequate procedure

Human telomerase reverse transcriptase mRNA expression assessed by real-time reverse transcription polymerase chain reaction predicts chemosensitivity in patients with ovarian carcinoma

Purpose: To evaluate in vivo whether the expression of the human telomerase reverse transcriptase (hTERT) gene, the catalytic subunit of the telomerase complex, is predictive of response to chemotherapy in ovarian cancer patients. Patients and Methods: Fifty-nine advanced-stage ovarian cancer patients who were treated with platinum-based chemotherapy were studied. hTERT levels were evaluated by real-time reverse transcriptase polymerase chain reaction (RT-PCR) on tumor specimens obtained before the treatment. Variables were analyzed by the χ2 and Fisher's exact tests. Logistic regression analysis was also performed to account for the effects of all the covariates investigated (residual disease, stage, histotype, and grade). Results: Twenty-eight (47%) of the 59 tumors showed low hTERT levels, whereas 31 (53%) tumors displayed high hTERT levels. Seventy-five percent of complete responders showed high levels of hTERT expression, whereas 66% of partial responders or nonresponders exhibited low HTERT levels (P = .002). Only residual disease and hTERT expression were independent predictors of response (odds ratios, 13.455 and 7.586, respectively). The combination of these two parameters provides powerful predictive information: 18 of the 20 patients with residual disease more than 2 cm and low hTERT levels were partial responders or nonresponders, whereas 11 of the 12 patients with residual disease less than 2 cm and high hTERT levels showed a complete response (χ2 = 21,416; P < .00001). Conclusion: Our data indicate that hTERT expression, measured by real-time RT-PCR, is a possible independent marker of response to platinum-based therapy in advanced stage ovarian cancer patients. Prospective validation of this marker will be required to further define its predictive value

Prediction of survival in stage I lung carcinoma patients by telomerase function evaluation

Telomerase activity and telomerase reverse transcriptase (hTERT) expression are elevated in human malignancies. We have investigated telomerase activity measured by the telomeric repeat amplification protocol (TRAP) assay and hTERT levels by real-time RT-PCR in stage I non-small-cell lung carcinomas. The purposes of our study included the comparison of these two techniques in the assessment of telomerase function and the evaluation of their prognostic significance. Telomerase activity and hTERT levels were determined in 90 stage I non-small-cell lung carcinoma patients, using TRAP assay and real-time RT-PCR, respectively. Variables were analyzed by the chi(2) and Fisher exact tests. Survival was analyzed by the Kaplan-Meier method. Multivariate analysis was performed with the Cox's proportional hazards model. Telomerase activity was elevated in 60 (67%) carcinomas. hTERT was elevated in 43 (48%) carcinomas. Only 21 (23%) tumors had low telomerase function by both TRAP and hTERT expression levels. Telomerase activity and hTERT were significantly correlated (p = 0.017), although 35 cases displayed discordant results. Both telomerase activity and hTERT levels were significantly associated with poor patient overall and disease-free survival (p = 0.019 and p = 0.018 for TRAP, and p = 0.011 and p = 0.012 for hTERT, respectively). Among the 21 patients with tumors displaying low telomerase function, defined by both TRAP and hTERT expression levels, only one succumbed to the disease (p = 0.0053). Our results suggest that the two techniques used in this study evaluate separate aspects of telomerase function and their combination provides powerful prognostic information in lung cancer patients