43 research outputs found
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
Environmental, Social and Economic Resilience in Multi-Residential Buildings: Assessing SBToolCZ Rating System
Sustainable Building Tool for the Czech Republic (SBToolCZ) is the Czech national green building rating system that encourages the design of sustainable buildings by incentivising reductions in energy, water, and building materials consumption, as well as improving occupant health and community connections. In addition to reducing the overall environmental impacts, certified green buildings must also be resilient enough to withstand external stressors, most frequently the symptoms of climatic change that may arise throughout the building's lifetime. Therefore, a resilient building should be capable of adapting and remaining functional under the pressure of more frequent and severe challenges. The purpose of this study is to examine where the SBToolCZ certification system has inherent overlaps with the topics of resilience, considering the environmental, social and economic factors relevant to Central European contexts. This is accomplished by comparing the criteria of this certification system with the most accepted principles of resilient design that have emerged from the international resilience rating systems or guidelines. A number of synergistic opportunities, as well as improvements for better integrating resilient design into the SBToolCZ framework and, therefore, into green construction, are discussed to implement existing criteria or propose supplementary ones. A key component of implementing resilience for multi-residential buildings is the SBToolCZ Site category, which is key to addressing the unique regional needs of each project and should be integrated with resilience-enhancement indicators. Finally, climate projections should be used instead of historical climate data at an early design stage to improve the resilience of the building
Selective regulation of recombinantly expressed mGlu7 metabotropic glutamate receptors by G protein-coupled receptor kinases and arrestins
mGlu7 receptors are coupled to Gi/Go-proteins and activate multiple transduction pathways, including inhibition of adenylyl cyclase activity and stimulation of ERK1/2 and JNK pathways. mGlu7 receptors play an important role in cognition and emotion and are involved in stress-related disorders such as anxiety and depression and in susceptibility to convulsive seizures. In spite of these potential clinical implications, little is known on the mechanisms that regulate mGlu7-receptor signaling. Here we show that mGlu7 receptor-dependent signaling pathways were regulated in a complementary manner by different GRK subtypes, with GRK4 affecting the adenylyl cyclase and the JNK pathways, and GRK2 selectively affecting the ERK1/2 pathway. Additionally we found that the two isoforms of non-visual arrestins, i.e. β-arrestin1 and β-arrestin2, exerted opposite effects on mGlu7-receptor signaling, with β-arrestin1 positively modulating ERK1/2 and inhibiting JNK, and β-arrestin2 doing the opposite. This represents a remarkable example of "reciprocal regulation" of receptor signaling by the two isoforms of β-arrestin. Finally we found that β-arrestin1 amplified mGlu7 receptor-dependent ERK1/2 activation in response to L-AP4 (an orthosteric agonist), but not in response to AMN082 (an atypical mGlu7-receptor allosteric agonist). The different effect of β-arrestin1 on L-AP4- and AMN082-stimulated ERK1/2 phosphorylation is in line with the emerging concept of β-arrestin-biased agonists. The present study may open new perspectives in elucidating the physio-pathological roles of the mGlu7 receptor and may provide new insights for the possibility to develop specific (biased) agonists that can selectively activate different signaling pathways
Selective regulation of recombinantly expressed mGlu7 metabotropic glutamate receptors by G protein-coupled receptor kinases and arrestins
mGlu7 receptors are coupled to Gi/Go-proteins and activate multiple transduction pathways, including inhibition of adenylyl cyclase activity and stimulation of ERK1/2 and JNK pathways. mGlu7 receptors play an important role in cognition and emotion and are involved in stress-related disorders such as anxiety and depression and in susceptibility to convulsive seizures. In spite of these potential clinical implications, little is known on the mechanisms that regulate mGlu7-receptor signaling. Here we show that mGlu7 receptor-dependent signaling pathways were regulated in a complementary manner by different GRK subtypes, with GRK4 affecting the adenylyl cyclase and the JNK pathways, and GRK2 selectively affecting the ERK1/2 pathway. Additionally we found that the two isoforms of non-visual arrestins, i.e. β-arrestin1 and β-arrestin2, exerted opposite effects on mGlu7-receptor signaling, with β-arrestin1 positively modulating ERK1/2 and inhibiting JNK, and β-arrestin2 doing the opposite. This represents a remarkable example of "reciprocal regulation" of receptor signaling by the two isoforms of β-arrestin. Finally we found that β-arrestin1 amplified mGlu7 receptor-dependent ERK1/2 activation in response to L-AP4 (an orthosteric agonist), but not in response to AMN082 (an atypical mGlu7-receptor allosteric agonist). The different effect of β-arrestin1 on L-AP4- and AMN082-stimulated ERK1/2 phosphorylation is in line with the emerging concept of β-arrestin-biased agonists. The present study may open new perspectives in elucidating the physio-pathological roles of the mGlu7 receptor and may provide new insights for the possibility to develop specific (biased) agonists that can selectively activate different signaling pathways
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
Multi-Objective Blended Ensemble for Highly Imbalanced Sequence Aware Tweet Engagement Prediction
In this paper we provide a description of the methods we used as team BanaNeverAlone for the ACM RecSys Challenge 2020, organized by Twitter. The challenge addresses the problem of user engagement prediction: the goal is to predict the probability of a user engagement (Like, Reply, Retweet or Retweet with comment), based on a series of past interactions on the Twitter platform. Our proposed solution relies on several features that we extracted from the original dataset, as well as on consolidated models, such as gradient boosting for decision trees and neural networks. The ensemble model, built using blending, and a multi-objective optimization allowed our team to rank in position 4
Progetto di edificio di servizio per la riqualificazione del sistema dei teatri di Parma
il prodotto riguarda una proposta progettuale per il sistema teatrale di Parma redatta in occasione di un seminario internazionale di progettazion
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