Metal additive manufacturing (AM) has developed rapidly over the last decade to become a disruptive technology capable of revolutionizing the way that products from various industrial sectors such as ...biomedical, aerospace, automotive, marine and offshore are designed. Early adopters of the technology like the biomedical and aerospace industries have shown that the better-designed components offer substantial performance improvements over current designs. However, in-depth and comprehensive views on the microstructure and mechanical properties of additively manufactured metals and alloys are less reported. To realize the full design potential that metal AM can offer, especially for load-bearing structural components, it is imperative to provide a thorough understanding on the anisotropic and heterogeneous microstructure and mechanical properties that often occur within metal AM parts. This paper outlines a broad range of metal AM technologies and reviews literatures on the anisotropy and heterogeneity of microstructure and mechanical properties for metal AM parts. It can be highlighted that the contributing factors to the anisotropy and heterogeneity within metal AM parts were either their unique microstructural features or manufacturing deficiencies. Concluding remarks on the state-of-the-art research regarding this topic and the possible solutions to overcome the anisotropy and heterogeneity of metal AM parts are provided.
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•The major metal AM systems and their processing conditions•The contributing factors on anisotropy and heterogeneity of microstructure and mechanical properties in metal AM parts•A critical review on anisotropic and heterogeneous mechanical properties of various metal AM parts•State-of-the-art development in numerical modelling to predict anisotropy and heterogeneity in metal AM parts
Acute colonic diverticulitis is one of the most common clinical conditions encountered by surgeons in the acute setting. An international multidisciplinary panel of experts from the World Society of ...Emergency Surgery (WSES) updated its guidelines for management of acute left-sided colonic diverticulitis (ALCD) according to the most recent available literature. The update includes recent changes introduced in the management of ALCD. The new update has been further integrated with advances in acute right-sided colonic diverticulitis (ARCD) that is more common than ALCD in select regions of the world.
Background
Lipoblastoma is a rare, benign, encapsulated tumor arising from embryonic white fat. On histology they typically contain variably differentiated adipocytes, primitive mesenchymal cells, ...myxoid matrix, and fibrous trabeculae. The tumor occurs primarily in infancy and early childhood. It often occurs in the extremities and trunk, and rarely develops in the head and neck and other sites.
Methods
Ten cases of histopathologically proven lipoblastoma presenting to our hospital during a 6-year period (2003–2008) were reviewed retrospectively for their clinical presentations, treatment, postoperative outcome, and follow-up.
Results
There were five males and five females ranging in age from 6 months to 20 years. The commonest presentation was a painless rapidly growing mass. Tumors occurred in an extremity (
n
= 5), head and neck (
n
= 3), trunk (
n
= 1), and retroperitoneum (
n
= 1). Preoperative diagnosis was accurate in only one case. The largest tumor measuring 25-cm × 20-cm × 7-cm and weighing 1.9 kg was excised from the retroperitoneum. All patients underwent complete surgical excision. Patient follow-up period ranging from 9 to 76 months showed no recurrences and no metastases.
Conclusions
Lipoblastoma behaves benignly, occurs in both superficial and deep sites, and occasionally attains large size. Complete surgical excision is the treatment of choice and long-term follow-up is required because there is a reported tendency for these tumors to recur.
Carbide precipitation plays a key role in determining mechanical properties of Co-Cr-Mo alloy. Precipitation characteristics of carbides in selective electron beam melting (SEBM)-fabricated Co-Cr-Mo ...parts have been investigated by atom probe tomography and transmission electron microscopy. We observe co-existence of two types of carbides, i.e. M23C6 and M6C, which are formed into continuous carbide thin films along columnar grain boundaries. The carbide thin film is found to precipitate coherently with one γCo grain while incoherently with another adjacent one. Moreover, columnar carbide chains or clusters consisting of nanometer-sized, cuboidal particles are precipitated coherently with surrounding γCo phase within interdendritic regions.
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The interleukin-13 receptor alpha2 (IL-13Rα2) is a cancer-associated receptor overexpressed in human glioblastoma multiforme (GBM). This receptor is undetectable in normal brain which makes it a ...highly suitable target for diagnostic and therapeutic purposes. However, the pathological role of this receptor in GBM remains to be established. Here we report that IL-13Rα2 alone induces invasiveness of human GBM cells without affecting their proliferation. In contrast, in the presence of the mutant EGFR (EGFRvIII), IL-13Rα2 promotes GBM cell proliferation in vitro and in vivo. Mechanistically, the cytoplasmic domain of IL-13Rα2 specifically binds to EGFRvIII, and this binding upregulates the tyrosine kinase activity of EGFRvIII and activates the RAS/RAF/MEK/ERK and STAT3 pathways. Our findings support the "To Go or To Grow" hypothesis whereby IL-13Rα2 serves as a molecular switch from invasion to proliferation, and suggest that targeting both receptors with STAT3 signaling inhibitor might be a therapeutic approach for the treatment of GBM.
Background:
Administration of non-beneficial life-sustaining treatments in terminal elderly patients still occurs due to lack of knowledge of patient’s wishes or delayed physician–family ...communications on preference.
Aim:
To determine whether advance care documentation encourages healthcare professional’s timely engagement in end-of-life discussions.
Design:
Systematic review of the English language articles published from January 2000 to April 2015.
Data sources:
EMBASE, MEDLINE, EBM REVIEWS, PsycINFO, CINAHL and Cochrane Library and manual searches of reference lists.
Results:
A total of 24 eligible articles from 10 countries including 23,914 subjects met the inclusion criteria, mostly using qualitative or mixed methods, with the exception of two cohort studies. The influence of advance care documentation on initiation of end-of-life discussions was predominantly based on perceptions, attitudes, beliefs and personal experience rather than on standard replicable measures of effectiveness in triggering the discussion. While health professionals reported positive perceptions of the use of advance care documentations (18/24 studies), actual evidence of their engagement in end-of-life discussions or confidence gained from accessing previously formulated wishes in advance care documentations was not generally available.
Conclusion:
Perceived effectiveness of advance care documentation in encouraging end-of-life discussions appears to be high but is mostly derived from low-level evidence studies. This may indicate a willingness and openness of patients, surrogates and staff to perceive advance directives as an instrument to improve communication, rather than actual evidence of timeliness or effectiveness from suitably designed studies. The assumption that advance care documentations will lead to higher physicians’ confidence or engagement in communicating with patients/families could not be objectively demonstrated in this review.
Health science students are the future healthcare workforce. Understanding and fostering a sustainable educational environment (EE) is essential in optimising their learning and the successful ...completion of their studies. A convergent mixed-methods study was conducted to explore health science students’ experiences of their EE at the largest public university in Brunei Darussalam. A cross-sectional design using the DREEM questionnaire (n = 150) and four focus group discussions (n = 31) involving five health science programs (biomedical sciences, dentistry, medicine, nursing/midwifery, and pharmacy) was conducted between November 2021 and May 2022. Descriptive and linear regression analyses and thematic analysis were respectively performed on the quantitative and qualitative data. Although the university EE was experienced by students as “more positive than negative” (86.7%), 13.3% perceived it as having “plenty of problems”. This perception of learning was statistically significant among nursing/midwifery students (p = 0.012). Dentistry students reported positive perceptions across all five domains of the DREEM (an overall mean of 119.3 ± 10.3). The importance of a stimulating home learning environment, supportive peers, innovative teaching methods, soft skill development, and clinical learning enhancement were highlighted. To foster independence and student-centred learning, an educational program that empowers students on their EE, including ‘survival skills’ is recommended. Future research should compare health science students’ experiences in university and clinical EE, nationally and abroad (medical and dentistry twinning program), and develop indicators measuring the sustainability of the EE throughout health science programs.
We present the first multiplicity-dedicated long-baseline optical interferometric survey of the Scorpius-Centaurus-Lupus-Crux association. We used the Sydney University Stellar Interferometer to ...undertake a survey for new companions to 58 Sco-Cen B-type stars and have detected 24 companions at separations ranging from 7 to 130 mas, 14 of which are new detections. Furthermore, we use a Bayesian analysis and all available information in the literature to determine the multiplicity distribution of the 58 stars in our sample, showing that the companion frequency is f = 1.35 ± 0.25 and the mass ratio distribution is best described by q
γ with γ = −0.46, agreeing with previous Sco-Cen high-mass work and differing significantly from lower mass stars in Tau-Aur. Based on our analysis, we estimate that among young B-type stars in moving groups, up to 23 per cent are apparently single stars. This has strong implications for the understanding of high-mass star formation, which requires angular momentum dispersal through some mechanism such as formation of multiple systems.
Lentiviral vectors are a robust gene delivery tool for inducing transgene expression in a variety of cells. They are well suited to facilitate the testing of therapeutic candidate genes in vitro, due ...to relative ease of packaging and ability to transduce dividing and non-dividing cells. Our goal was to identify a gene that could be delivered to the heart to protect against cancer-therapy-induced cardiotoxicity. We sought to generate a lentivirus construct with a ubiquitous CMV promoter driving expression of B-cell lymphocyte/leukemia 2 gene (Bcl-2), a potent anti-apoptotic gene. Contrary to our aim, overexpression of Bcl-2 induced cell death in the producer HEK293T cells, resulting in failure to produce usable vector titre. This was circumvented by exchanging the CMV promoter to the cardiac-specific NCX1 promoter, leading to the successful production of a lentiviral vector which could induce cardioprotective expression of Bcl-2. In conclusion, reduced expression of Bcl-2 driven by a weaker promoter improved vector yield, and led to the production of functional cardioprotective Bcl-2 in primary cardiomyocytes.
Gene therapy is making significant impact on a modest, yet growing, number of human diseases. Justifiably, the preferred viral vector for clinical use is that based on recombinant adeno-associated ...virus (rAAV). There is a need to scale up rAAV vector production with the transition from pre-clinical models to human application. Standard production methods based on the adherent cell type (HEK293) are limited in scalability and other methods, such as those based on the baculovirus and non-adherent insect cell (Sf9) system, have been pursued as an alternative to increase rAAV production. In this study, we compare these two production methods for cardiotropic rAAVs. Transduction efficiency for both production methods was assessed in primary cardiomyocytes, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), and in mice following systemic delivery. We found that the rAAV produced by the traditional HEK293 method out-performed vector produced using the baculovirus/Sf9 system in vitro and in vivo. This finding provides a potential caveat for vector function when using the baculovirus/Sf9 production system and underscores the need for thorough assessment of vector performance when using diverse rAAV production methods.
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