Comparison of dimensional accuracies of stereolithography and powder binder printing

This paper presents a comparative experimental investigation of the dimensional accuracies of two widely used rapid prototyping (RP) processes: stereolithography (SLA) and powder binder printing (PBP). Four replicates of a purpose-designed component using each RP process were fabricated, and the measurements of the internal and external features of all surfaces were performed using a general-purpose coordinate measurement machine. The results showed that in both cases, the main cause of dimensional variations was the volumetric change inherent in the process. The precision of SLA was far better than that of PBP. The dimensional accuracy of SLA was better in the z direction, whereas PBP produced better dimensional accuracy in the x–y plane. In both RP processes, the height error consisted of two components: constant error and cumulative error. The constant error component was equal to the datum surface error. SLA yielded an average datum surface error that was 68 % higher than in PBP. The height error of SLA improved with the increase in nominal height, whereas it deteriorated in PBP

Tumor cell survival pathways activated by photodynamic therapy: a molecular basis for pharmacological inhibition strategies

Photodynamic therapy (PDT) has emerged as a promising alternative to conventional cancer therapies such as surgery, chemotherapy, and radiotherapy. PDT comprises the administration of a photosensitizer, its accumulation in tumor tissue, and subsequent irradiation of the photosensitizer-loaded tumor, leading to the localized photoproduction of reactive oxygen species (ROS). The resulting oxidative damage ultimately culminates in tumor cell death, vascular shutdown, induction of an antitumor immune response, and the consequent destruction of the tumor. However, the ROS produced by PDT also triggers a stress response that, as part of a cell survival mechanism, helps cancer cells to cope with the PDT-induced oxidative stress and cell damage. These survival pathways are mediated by the transcription factors activator protein 1 (AP-1), nuclear factor E2-related factor 2 (NRF2), hypoxia-inducible factor 1 (HIF-1), nuclear factor κB (NF-κB), and those that mediate the proteotoxic stress response. The survival pathways are believed to render some types of cancer recalcitrant to PDT and alter the tumor microenvironment in favor of tumor survival. In this review, the molecular mechanisms are elucidated that occur post-PDT to mediate cancer cell survival, on the basis of which pharmacological interventions are proposed. Specifically, pharmaceutical inhibitors of the molecular regulators of each survival pathway are addressed. The ultimate aim is to facilitate the development of adjuvant intervention strategies to improve PDT efficacy in recalcitrant solid tumors

Editoriale. Ciò che la Psicologia ci dice delle scienze del nostro tempo

This is the final version of the article. Available from the publisher via the DOI in this record.Background: Chronic musculoskeletal pain is a common problem that is difficult to treat. Self-management support interventions may help people to manage this condition better; however, there is limited evidence showing that they improve clinical outcomes. Our overarching research question was ‘Does a self-management support programme improve outcomes for people living with chronic musculoskeletal pain?’. Aim: To develop, evaluate and test the clinical effectiveness and cost-effectiveness of a theoretically grounded self-management support intervention for people living with chronic musculoskeletal pain. Methods: In phase 1 we carried out two systematic reviews to synthesise the evidence base for self-management course content and delivery styles likely to help those with chronic pain. We also considered the psychological theories that might underpin behaviour change and pain management principles. Informed by these data we developed the Coping with persistent Pain, Evaluation Research in Self-management (COPERS) intervention, a group intervention delivered over 3 days with a top-up session after 2 weeks. It was led by two trained facilitators: a health-care professional and a layperson with experience of chronic pain. To ensure that we measured the most appropriate outcomes we reviewed the literature on potential outcome domains and measures and consulted widely with patients, tutors and experts. In a feasibility study we demonstrated that we could deliver the COPERS intervention in English and, to increase the generalisability of our findings, also in Sylheti for the Bangladeshi community. In phase 2 we ran a randomised controlled trial to test the clinical effectiveness and cost-effectiveness of adding the COPERS intervention to a best usual care package (usual care plus a relaxation CD and a pain toolkit leaflet). We recruited adults with chronic musculoskeletal pain largely from primary care and musculoskeletal physiotherapy services in two localities: east London and Coventry/Warwickshire. We collected follow-up data at 12 weeks (self-efficacy only) and 6 and 12 months. Our primary outcome was pain-related disability (Chronic Pain Grade disability subscale) at 12 months. We also measured costs, health utility (European Quality of Life-5 Dimensions), anxiety, depression [Hospital Anxiety and Depression Scale (HADS)], coping, pain acceptance and social integration. Data on the use of NHS services by participants were extracted from NHS electronic records. Results: We recruited 703 participants with a mean age of 60 years (range 19–94 years); 81% were white and 67% were female. Depression and anxiety symptoms were common, with mean HADS depression and anxiety scores of 7.4 [standard deviation (SD) 4.1] and 9.2 (SD 4.6), respectively. Intervention participants received 85% of the course content. At 12 months there was no difference between treatment groups in our primary outcome of pain-related disability [difference –1.0 intervention vs. control, 95% confidence interval (CI) –4.9 to 3.0]. However, self-efficacy, anxiety, depression, pain acceptance and social integration all improved more in the intervention group at 6 months. At 1 year these differences remained for depression (–0.7, 95% CI –1.2 to –0.2) and social integration (0.8, 95% CI, 0.4 to 1.2). The COPERS intervention had a high probability (87%) of being cost-effective compared with usual care at a threshold of £30,000 per quality-adjusted life-year. Conclusions: Although the COPERS intervention did not affect our primary outcome of pain-related disability, it improved psychological well-being and is likely to be cost-effective according to current National Institute for Health and Care Excellence criteria. The COPERS intervention could be used as a substitute for less well-evidenced (and more expensive) pain self-management programmes. Effective interventions to improve hard outcomes in chronic pain patients, such as disability, are still needed.The project was funded by the National Institute for Health Research Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 4, No. 14. See the NIHR Journals Library website for further project information