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Additively manufactured (AM) components offer superior design flexibility compared to their conventionally manufactured counterparts and require process parameter optimization to achieve high-quality depositions with desirable and predictable mechanical properties. This study was focused on 4340 steel fabricated using laser powder bed fusion (LPBF), and 42 laser power and scan speed combinations have been systematically investigated to optimize the melt pool geometry and ensure fully dense parts. The AM material was compared with a wrought 4340 equivalent and studied in both as-fabricated and heat-treated conditions. Two heat treatments were designed and used to optimize the materials for strength and toughness, respectively. Microstructure, tensile, and fractographic studies were conducted to assess build integrity and establish processing–structure–performance relationships. Tensile properties of the AM materials in all studied conditions were equivalent or better than the comparable wrought materials. The high performance of the AM materials was attributed to the absence of both manganese sulfide inclusions and rolling-induced banding, typically found in the wrought materials. The fine cellular substructure is thought to additionally contribute to the high strength of the as-fabricated AM material. Complementary to the knowledge that has emerged from the experimental investigations, the dataset was further leveraged to make recommendations for future design of experiments to optimize AM build parameters in other material systems. A statistical Monte Carlo analysis was used to predict the interpolation error produced when using reduced datasets and to enable informed processing parameters selection. These findings are discussed to make recommendations for the use of AM materials for high-integrity structural applications. [ABSTRACT FROM AUTHOR]

Background:Despite many studies on diet and bladder cancer, there are areas that remain unexplored including meat mutagens, specific vegetable groups, and vitamins from diet.Methods:We conducted a population-based case-control study of bladder cancer in Maine, New Hampshire, and Vermont. A total of 1171 cases were ascertained through hospital pathology records and cancer registries from 2001 to 2004. Overall, 1418 controls were identified from the Department of Motor Vehicles (<65 years) and Center for Medicaid and Medicare Services (65-79 years) and were frequency-matched to cases by state, sex, and age (within 5 years). Diet was assessed with a self-administered Diet History Questionnaire. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI).Results:Processed meat intake was positively associated with bladder cancer (highest vs lowest quartile OR: 1.28; 95% CI: 1.00-1.65; Ptrend=0.035), with a stronger association for processed red meat (OR: 1.41; 95% CI: 1.08-1.84; Ptrend=0.024). There were no associations between intake of fruits or vegetables and bladder cancer. We did, however, observe an inverse association with vitamin B12 intake (OR: 0.77; 95% CI: 0.61-0.99; P=0.019).Conclusion:Vitamin B12 from diet may be protective against bladder cancer, whereas consuming processed meat may increase risk. [ABSTRACT FROM AUTHOR]

Background: There are few known risk factors for renal cell carcinoma (RCC). Two small hospital-based case-control studies suggested an association between short blood telomere length (TL) and increased RCC risk.Methods: We conducted a large population-based case-control study in two metropolitan regions of the United States comparing relative TL in DNA derived from peripheral blood samples from 891 RCC cases and 894 controls. Odds ratios and 95% confidence intervals were estimated using unconditional logistic regression in both unadjusted and adjusted models.Results: Median TL was 0.85 for both cases and controls (P=0.40), and no differences in RCC risk by quartiles of TL were observed. Results of analyses stratified by age, sex, race, tumour stage, and time from RCC diagnosis to blood collection were similarly null. In multivariate analyses among controls, increasing age and history of hypertension were associated with shorter TL (P<0.001 and P=0.07, respectively), and African Americans had longer TL than Caucasians (P<0.001).Conclusion: These data do not support the hypothesis that blood TL is associated with RCC. This population-based case-control study is, to our knowledge, the largest investigation to date of TL and RCC. [ABSTRACT FROM AUTHOR]

Background: High-temperature cooked meat contains two families of carcinogens, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Given the kidneys' role in metabolism and urinary excretion of these compounds, we investigated meat-derived mutagens, as well as meat intake and cooking methods, in a population-based case-control study conducted in metropolitan Detroit and Chicago.Methods: Newly diagnosed, histologically confirmed adenocarcinoma of the renal parenchyma (renal cell carcinoma (RCC)) cases (n=1192) were frequency matched on age, sex, and race to controls (n=1175). The interviewer-administered Diet History Questionnaire (DHQ) included queries for meat-cooking methods and doneness with photographic aids. Levels of meat mutagens were estimated using the DHQ in conjunction with the CHARRED database.Results: The risk of RCC increased with intake of barbecued meat (P(trend)=0.04) and the PAH, benzo(a)pyrene (BaP) (multivariable-adjusted odds ratio and 95% confidence interval, highest vs lowest quartile: 1.50 (1.14, 1.95), P(trend)=0.001). With increasing BaP intake, the risk of RCC was more than twofold in African Americans and current smokers (P(interaction)<0.05). We found no association for HCAs or overall meat intake.Conclusion: BaP intake, a PAH in barbecued meat, was positively associated with RCC. These biologically plausible findings advocate further epidemiological investigation into dietary intake of BaP and risk of RCC. [ABSTRACT FROM AUTHOR]

Background:The association between renal cell carcinoma (RCC) risk and family history of cancer has not been examined with an adequate number of African Americans (AAs).Methods:In a population-based case–control study, unconditional logistic regression was used to calculate the association between RCC risk and a family history of cancer among 1217 RCC cases and 1235 controls.Results:Increased RCC risk was shown for subjects with at least one first-degree relative with kidney cancer (odds ratio=2.29; 95% confidence interval=1.31–4.00). No differences in risk were observed when analyses were stratified by race. For Caucasians, excess risk was observed among those reporting a sibling with kidney cancer, whereas for AAs, increased risk occurred among subjects reporting either a sibling or parent affected with the disease. A family history of non-renal cancers, and those related to smoking or to the von Hippel–Lindau syndrome, revealed no association with RCC risk.Conclusion:The RCC risk associated with a family history of kidney cancer is similar among Caucasians and AAs. [ABSTRACT FROM AUTHOR]