The strengthening effect of inter-layer cold working and post-deposition heat treatment on the additively manufactured Al-6.3Cu alloy

Wire + Arc Additive Manufacture (WAAM) attracts great interest from the aerospace industry for producing components with aluminum alloys, particularly Al-Cu alloy of the 2000 series such as 2219 alloy. However the application is restricted by the low strength properties of the as-deposited WAAM metal. In this study two strengthening methods were investigated - inter-layer cold working and post-deposition heat treatment. Straight wall samples were prepared with 2319 aluminum alloy wire. Inter-layer rolling with loads of 15 kN, 30 kN and 45 kN were employed during deposition. The ultimate tensile strength (UTS) and yield strength (YS) of the inter-layer rolled alloy with 45 kN load can achieve 314. MPa and 244. MPa respectively. The influence of post-deposition T6 heat treatment was investigated on the WAAM alloy with or without rolling. Compared with inter-layer rolling, post-deposition heat treatment can provide much greater enhancement of the strength. After T6 treatment, the UTS and YS of both of the as-deposited and 45 kN rolled alloys exceeded 450. MPa and 305. MPa respectively, which are higher than the properties of the wrought 2219-T6 alloy. The strengthening mechanisms of this additively manufactured Al-6.3Cu alloy were investigated through microstructure analysis

DETC2008-49230 ANALYTICAL ROBUST DESIGN OF MECHANICAL SYSTEMS

ABSTRACT Based on general principles of robust design and axiomatic design, relationship among robustness, structural parameters, design parameters and uncontrollable factors has been established. Various factors that affect system robustness were analyzed mathematically to determine the relationship between robustness and structural characteristics of the linear system. The relations among functional requirements were also explored. Accordingly, an optimization model was established to determine design parameters. This new robust design approach can be used for linear mechanical system analysis. Keywords: Quality, Robust, Sensitivity. 1 INTRODUCTION Quality is a primary factor in determining whether a product is successful in the market place. It can be evaluated if the product performs the intended functions. The intended functionality may be deviated by variations resulted from raw materials, manufacturing processes, and/or operational environments. To minimize the effects of the variations on functions, the functions pf product and system should be made insensitive to those variations. Dr.Taguchi has proposed robust design in 1970s' and this method has been widely used in industry Analytical robust design approach is a new method for design of robust mechanical systems. Through mapping from design parameters to functional requirements of system, this method aims to analyze the intrinsic relationships among structural characteristics, design parameters, uncontrollable factors and robustness of linear system. Based on Suh's Axiomatic Design and robust analysis of traditional robust design approach [3], this paper reports on studies of models of linear mechanical system for robust analysis, sensitivity index of system, and describes a optimal model of analytical robust design, reveals the primary factors on robustness. Examples were included to demonstrate this new approach. ROBUST ANALYSIS Models The factors that influence functions of linear system could be divided into controllable factors and uncontrollable factors. It is important to distinguish these factors appropriately and establish analytical models accordingly

Recent advances progress in radiotherapy for breast cancer after breast-conserving surgery: a review

Adjuvant radiotherapy after breast-conserving surgery has become an integral part of the treatment of breast cancer. In recent years, the development of radiotherapy technology has made great progress in this field, including the comparison of the curative effects of various radiotherapy techniques and the performance of the segmentation times. The choice of radiotherapy technology needs to be co-determined by clinical evidence practice and evaluated for each individual patient to achieve precision radiotherapy. This article discusses the treatment effects of different radiotherapy, techniques, the risk of second cancers and short-range radiation therapy techniques after breast-conserving surgery such as hypo fractionated whole breast irradiation and accelerated partial breast irradiation. The choice of radiotherapy regimen needs to be based on the individual condition of the patient, and the general principle is to focus on the target area and reduce the irradiation of the normal tissues and organs. Short-range radiotherapy and hypofractionated are superior to conventional radiotherapy and are expected to become the mainstream treatment after breast-conserving surgery

Excess Deaths of Gastrointestinal, Liver, and Pancreatic Diseases During the COVID-19 Pandemic in the United States

Objectives: To evaluate excess deaths of gastrointestinal, liver, and pancreatic diseases in the United States during the COVID-19 pandemic.Methods: We retrieved weekly death counts from National Vital Statistics System and fitted them with a quasi-Poisson regression model. Cause-specific excess deaths were calculated by the difference between observed and expected deaths with adjustment for temporal trend and seasonality. Demographic disparities and temporal-spatial patterns were evaluated for different diseases.Results: From March 2020 to September 2022, the increased mortality (measured by excess risks) for Clostridium difficile colitis, gastrointestinal hemorrhage, and acute pancreatitis were 35.9%; 24.8%; and 20.6% higher than the expected. For alcoholic liver disease, fibrosis/cirrhosis, and hepatic failure, the excess risks were 1.4–2.8 times higher among younger inhabitants than older inhabitants. The excess deaths of selected diseases were persistently observed across multiple epidemic waves with fluctuating trends for gastrointestinal hemorrhage and fibrosis/cirrhosis and an increasing trend for C. difficile colitis.Conclusion: The persistently observed excess deaths of digestive diseases highlights the importance for healthcare authorities to develop sustainable strategies in response to the long-term circulating of SARS-CoV-2 in the community

NF-kappaB P50/P65 hetero-dimer mediates differential regulation of CD166/ALCAM expression via interaction with micoRNA-9 after serum deprivation, providing evidence for a novel negative auto-regulatory loop

CD166/ALCAM plays an important role in tumor aggression and progression as well as protecting cancer cells against apoptosis and autophagy. However, the mechanism by which pro-cell death signals control CD166 expression remains unclear. Here we show that following serum deprivation (SD), upregulation of CD166 protein is shorter than that of CD166 mRNA. Molecular analysis revealed both CD166 and miR-9-1 as two novel NF-κB target genes in hepatoma cells. In vivo activation and translocation of the NF-κB P50/P65 hetero-dimer into the nucleus following the phosphorylation and accompanied degradation of its inhibitor, IκBα, contributes to efficient transcription of both genes following SD. We show that following serum starvation, delayed up-regulation of miR-9 represses translation of CD166 protein through its target sites in the 3′-UTR of CD166 mRNA. We also propose that miR-9 promotes cell migration largely due to inhibition of CD166. Collectively, the study elucidates a novel negative auto-regulatory loop in which NF-κB mediates differential regulation of CD166 after SD

Internal mammary lymph node recurrence: rare but characteristic metastasis site in breast cancer

<p>Abstract</p> <p>Background</p> <p>To assess the frequency of IMLN recurrence, its associated risk factors with disease-free interval (DFI) and its predicting factors on overall survival time.</p> <p>Methods</p> <p>133 cases of breast cancer IMLN recurrence were identified via the computerized CT reporting system between February 2003 and June 2008, during which chest CT for patients with breast cancer (n = 8867) were performed consecutively at Cancer Hospital, Fudan University, Shanghai, China. Patients' charts were retrieved and patients' characteristics, disease characteristics, and treatments after recurrence were collected for analysis. The frequency was 1.5% (133/8867).</p> <p>Results</p> <p>IMLN recurrence was presented as the first metastatic site in 121 (91%) patients while 88 (66.2%) had other concurrent metastases. Typical chest CT images included swelling of the IMLN at the ipsilateral side with local lump and sternal erosion located mostly between the second and third intercostal space. The median disease-free interval (DFI) of IMLN recurrence was 38 months. The independent factors that could delay the IMLN recurrence were small tumor size (HR 0.5 95%CI: 0.4 - 0.8; <it>p </it>= 0.002), and positive ER/PR disease (HR 0.6, 95% CI: 0.4 - 0.9; <it>p </it>= 0.006). The median survival time after IMLN recurrence was 42 months, with a 5-year survival rate of 30%. Univariate analysis showed four variables significantly influenced the survival time: DFI of IMLN recurrence (p = 0.001), no concurrent distant metastasis (p = 0.024), endocrine therapy for patients with positive ER/PR (p = 0.000), radiotherapy (p = 0.040). The independent factors that reduced the death risk were no concurrent distant metastases (HR: 0.7, 95% CI: 0.4 - 0.9; <it>p </it>= 0.031), endocrine therapy for patients with positive ER/PR status (HR: 0.2, 95% CI: 0.1 - 0.5; <it>p </it>= 0.001) and palliative radiotherapy (HR: 0.3, 95% CI: 0.1- 0.9; <it>p </it>= 0.026).</p> <p>Conclusions</p> <p>The risk of IMLN recurrence is low and there are certain characteristics features on CT images. ER/PR status is both a risk factor for DFI of IMLN recurrence and a prognostic factor for overall survival after IMLN recurrence. Patients with only IMLN recurrence and/or local lesion have a good prognosis.</p

Enhancement of the antituberculosis activity of weak acids by inhibitors of energy metabolism but not by anaerobiosis suggests that weak acids act differently from the front-line tuberculosis drug pyrazinamide

Mycobacterium tuberculosis is uniquely susceptible to weak acids compared with other mycobacteria or bacteria. The antituberculosis activity of the front-line drug pyrazinamide (PZA), a weak acid (pyrazinoic acid) precursor, can be enhanced by inhibitors of energy metabolism and anaerobiosis. Here, we investigated the effect of inhibitors of energy metabolism and anaerobiosis on weak acid activity against M. tuberculosis in general. The susceptibility of M. tuberculosis to benzoic acid (BA) esters and amides was determined alone and in the presence of inhibitors of energy metabolism such as N,N'-dicyclohexylcarbodiimide (DCCD) and azide and also under anaerobic conditions in the form of MIC and drug exposure followed by colony count. Some BA esters such as propyl hydroxybenzoic acid and 4-dodecyloxylbenzoic acid had significant activity whereas amides of BA had no activity. As for PZA, inhibitors of energy metabolism DCCD and azide enhanced the antituberculosis activity of weak acids under normal atmospheric oxygen tension. However, unlike PZA, weak acids did not show antituberculosis activity and the inhibitors of energy metabolism did not enhance the weak acid activity under anaerobic conditions. The enhancement of weak acid activity by inhibitors of energy metabolism for M. tuberculosis was not seen in other bacterial species such as Helicobacter pylori. These results suggest that while the antituberculosis activity of weak acids can be enhanced by inhibitors of energy metabolism as for PZA, weak acids act differently from PZA in that they were inactive against M. tuberculosis under anaerobic conditions. The significance of these findings is discussed in the context of the unique physiology of M. tuberculosis and the development of new tuberculosis drugs.. - NIH [AI44063, AI49485]; Basic Research (973) Program [2005013523102]. - Y. Z. was supported by NIH grants AI44063 and AI49485, and the Basic Research (973) Program (2005013523102), China. We thank jiangbing Zhou for help with data analysis

Reducing effects of design uncertainties on product sustainability

Product designers need to consider users’ requirement changes in the product life cycle. Existing practices of product design lack an effective method to quantify uncertainty effects on products. This research proposes a method to evaluate product sustainability under the generational variety uncertainty. An integrated method of agent-based modeling, quality function deployment (QFD), and axiomatic design theory is developed to simulate users’ preference changes. The contribution in this paper is to address all sustainability pillars including the social, environmental, and economy in the proposed solution. The quantified uncertainty is then used to evaluate impacts on product sustainability. The proposed method is validated using an example of the wheelchair design