Analysis and Optimization of Autofrettaged and Shrink-Fitted Compound Cylinders under Thermo-Mechanical Loads

Cylindrical shells have large industrial applications ranging from pressure vessels, engine cylinders and hydraulic chambers to chemical and power plants and they are typically subjected to severe mechanical or thermo-mechanical environmental conditions. The fatigue life, pressure and thermal load bearing capacities of thick-walled cylinders can be considerably improved by inducing near the bore compressive residual hoop stresses. Shrink-fit and autofrettage processes have been effectively applied to generate favorable compressive residual stresses. The main goal of this research study is to fundamentally investigate the compound cylinders subjected to autofrettage and shrink-fit processes and develop new design processing technique and practical design optimization strategies to enhance their fatigue life under cyclic thermo-mechanical loads. First, the residual stresses of compound cylinders subjected to different combinations of shrink-fit and autofrettage processes have been evaluated using the developed finite element model in the ANSYS environment. The stresses due to different cyclic thermo-mechanical loads have also been calculated for the different combinations of compound cylinders considering the fully coupled thermo-elastic finite element model. To validate the finite element model, an experimental setup has been designed to measure the temperature history at three different locations through the wall thickness and also hoop strain at the outer surface of a two-layer compound cylinder under internal quasi-static and cyclic thermal loads. The experimental results have then been compared with those obtained from the finite element model. Moreover, to compare the performance of compound cylinders under different thermo-mechanical loads, the fatigue life due to cyclic pressure, cyclic thermal pulses and cyclic combined thermo-mechanical pulses has been calculated using ASME code for high pressure vessel. Next, to enhance the residual stress distribution along the wall thickness of the cylinder, a new double autofrettage process has been introduced. In the proposed double autofrettage process, an outer autofrettage cycle is performed prior to a standard inner autofrettage cycle. This can provide an increase in the beneficial compressive residual stresses at the near bore area of the cylinder while decreasing the detrimental tensile residual stress at the outer part of the cylinder. The proposed process has then been utilized to construct new combinations of autofrettage, shrink-fit and double autofrettage processes. The residual stress distribution through the thickness and fatigue life of these new combinations have been evaluated and compared with those based on conventional combinations of shrink-fit and autofrettage processes. Finally, a practical design optimization methodology has been developed to identify the optimal configuration of autofrettaged and shrink-fitted cylinders. Optimization problems based on the high-fidelity finite element model is computationally very expensive and may not render accurate optimum results. Considering this in the presented research, design of experiment (DOE) and response surface method (RSM) have been used in combination with the finite element model to create smooth response surface functions which can accurately describe the behavior of the residual hoop stresses with respect to the change of design variables. The developed response surface functions have been effectively utilized in the design optimization problems to simultaneously maximize the residual compressive hoop stress and minimize the residual tensile hoop stress through the thickness of the compound cylinder. Nonlinear mathematical programming technique based on the powerful sequential quadratic programming (SQP) algorithm has been used in combination with the genetic algorithm (GA) in order to accurately capture the global optimal solutions. At the end, the residual hoop stress distribution and fatigue life of the optimum configurations for each combination of autofrettage and shrink-fit processes have been evaluated and compared

Design Optimisation of Muzzle Brake for Sniper Rifle

Muzzle brakes (MBs) have a great effect on reducing the recoil force of weapons during firing. In this paper, optimum MB efficiency, MB force and recoil force for (12,7 x 99 mm) sniper rifle have been studied. The objective is to obtain the optimum area of side openings, inclination angle and number of chambers for the MB in order to increase the MB efficiency and MB force and thereby to decrease their coil force of the weapon. An analytical model for calculating MB efficiency, MB force and weapon recoil force for MBs of two, three and four chambers has been established. This Model is then utilised in combination with design of experiment (DOE) and Response Surface Method (RSM) statistical techniques to develop a smooth response function which can be efficiently used in optimisation formulation. Finally, multi objectives generic algorithm (MOGA) optimisation method has been employed to find the optimum MB design parameters. The optimisation results show that the three or four chambers MBs have no significant effect on reducing the weapon recoil force compared with the two chamber MB for this sniper rifle

Serrate RNA effector molecule (SRRT) is associated with prostate cancer progression and is a predictor of poor prognosis in lethal prostate cancer

Arsenite-resistance protein 2, also known as serrate RNA effector molecule (ARS2/SRRT), is known to be involved in cellular proliferation and tumorigenicity. However, its role in prostate cancer (PCa) has not yet been established. We investigated the potential role of SRRT in 496 prostate samples including benign, incidental, advanced, and castrate-resistant patients treated by androgen deprivation therapy (ADT). We also explored the association of SRRT with common genetic aberrations in lethal PCa using immunohistochemistry (IHC) and performed a detailed analysis of SRRT expression using The Cancer Genome Atlas (TCGA PRAD) by utilizing RNA-seq, clinical information (pathological T category and pathological Gleason score). Our findings indicated that high SRRT expression was significantly associated with poor overall survival (OS) and cause-specific survival (CSS). SRRT expression was also significantly associated with common genomic aberrations in lethal PCa such as PTEN loss, ERG gain, mutant TP53, or ATM. Furthermore, TCGA PRAD data revealed that high SRRT mRNA expression was significantly associated with higher Gleason scores, PSA levels, and T pathological categories. Gene set enrichment analysis (GSEA) of RNAseq data from the TCGA PRAD cohort indicated that SRRT may play a potential role in regulating the expression of genes involved in prostate cancer aggressiveness. Conclusion: The current data identify the SRRT's potential role as a prognostic for lethal PCa, and further research is required to investigate its potential as a therapeutic target.Prostate Cancer Foundation Young Investigator Award ; Prostate Cancer Canada ; Canadian Cancer Society (CCS

The curious case of Prevotella copri

ABSTRACTPrevotella copri is an abundant member of the human gastrointestinal microbiome, whose relative abundance has curiously been associated with positive and negative impacts on diseases, such as Parkinson’s disease and rheumatoid arthritis. Yet, the verdict is still out on the definitive role of P. copri in human health, and on the effect of different diets on its relative abundance in the gut microbiome. The puzzling discrepancies among P. copri studies have only recently been attributed to the diversity of its strains, which substantially differ in their encoded metabolic patterns from the commonly used reference strain. However, such strain differences cannot be resolved by common 16S rRNA amplicon profiling methods. Here, we scrutinize P. copri, its versatile metabolic potential, and the hypotheses behind the conflicting observations on its association with diet and human health. We also provide suggestions for designing studies and bioinformatics pipelines to better research P. copri

ARPC1B Is Associated with Lethal Prostate Cancer and Its Inhibition Decreases Cell Invasion and Migration In Vitro

ARPC1B (Actin Related Protein 2/3 Complex Subunit 1B) has been found to be involved in platelet abnormalities of immune-mediated inflammatory disease and eosinophilia. However, its role in prostate cancer (PCa) has not been established. We characterized the role of ARPC1B in PCa invasion and metastasis and investigated its prognosis using in vitro cellular models and PCa clinical data. Higher immunohistochemistry (IHC) expressions of ARPC1B were observed in localized and castrate resistant PCa (CRPC) vs. benign prostate tissue (p < 0.01). Additionally, 47% of patients with grade group 5 (GG) showed high ARPC1B expression vs. other GG patients. Assessing ARPC1B expression in association with two of the common genetic aberrations in PCa (ERG and PTEN) showed significant association to overall and cause-specific survival for combined assessment of ARPC1B and PTEN, and ARPC1B and ERG. Knockdown of ARPC1B impaired the migration and invasion of PC3 and DU145 PCa cells via downregulation of Aurora A kinase (AURKA) and resulted in the arrest of the cells in the G2/M checkpoint of the cell cycle. Additionally, higher ARPC1B expression was observed in stable PC3-ERG cells compared to normal PC3, supporting the association between ERG and ARPC1B. Our findings implicate the role of ARPC1B in PCa invasion and metastasis in association with ERG and further support its prognostic value as a biomarker in association with ERG and PTEN in identifying aggressive phenotypes of PCa cancer

Serrate RNA Effector Molecule (SRRT) Is Associated with Prostate Cancer Progression and Is a Predictor of Poor Prognosis in Lethal Prostate Cancer.

Arsenite-resistance protein 2, also known as serrate RNA effector molecule (ARS2/SRRT), is known to be involved in cellular proliferation and tumorigenicity. However, its role in prostate cancer (PCa) has not yet been established. We investigated the potential role of SRRT in 496 prostate samples including benign, incidental, advanced, and castrate-resistant patients treated by androgen deprivation therapy (ADT). We also explored the association of SRRT with common genetic aberrations in lethal PCa using immunohistochemistry (IHC) and performed a detailed analysis of SRRT expression using The Cancer Genome Atlas (TCGA PRAD) by utilizing RNA-seq, clinical information (pathological T category and pathological Gleason score). Our findings indicated that high SRRT expression was significantly associated with poor overall survival (OS) and cause-specific survival (CSS). SRRT expression was also significantly associated with common genomic aberrations in lethal PCa such as PTEN loss, ERG gain, mutant TP53, or ATM. Furthermore, TCGA PRAD data revealed that high SRRT mRNA expression was significantly associated with higher Gleason scores, PSA levels, and T pathological categories. Gene set enrichment analysis (GSEA) of RNAseq data from the TCGA PRAD cohort indicated that SRRT may play a potential role in regulating the expression of genes involved in prostate cancer aggressiveness. Conclusion: The current data identify the SRRTs potential role as a prognostic for lethal PCa, and further research is required to investigate its potential as a therapeutic target

Molecular characterization of prostate cancer in Middle Eastern population highlights differences with Western populations with prognostic implication

BACKGROUND: To investigate the incidence and prognostication of ERG, PTEN and SPINK1 protein expressions in prostate cancer cohort of Middle Eastern descent in comparison to published data from Western population. METHODS: Immunohistochemistry for ERG, PTEN and SPINK1 was performed in a cohort of localized PCA (n = 340). The data were correlated to pathological and clinical outcomes and compared to Western populations. RESULTS: ERG expression and PTEN loss were noted in 123/288 (42.7%) and 91/297 (30.6%) of patients, respectively. SPINK1 expression was assessed in a subset of cases, noted in 6/150 (4%) of patients. Only ERG expression was associated with grade groups, being more common in the lower grade groups (1-3 vs 4-5; p = 0.04). In contrast to the Western population, PTEN loss foci were more likely to be ERG negative, observed in 81% of tumor foci and patients with PTEN neg/ERG pos were more likely to exhibit biochemical recurrence (OR 2.831; 95% CI 1.10-726, p = 0.03). This association remained significant in multivariate analysis (OR 2.68; 95% CI 0.98-7.33, p = 0.05), after adjusting for GG, path stage and surgical margin. CONCLUSION: This study documents significant differences in key molecular events in PCA in Middle Eastern population compared to Western populations that could explain differences in PCA incidence, progression and prognostication. ERG, PTEN and SPINK1 genomic alteration occur less frequently and the enrichment of ERG for PTEN loss is not observed. Additionally, patients with combined PTEN loss/ERG positive are at highest risk for BCR vs North American Caucasian population where PTEN loss alone seems to be associated with the worst clinical outcome. The data presented here further support differences in clonal evolution between Middle Eastern and Western population in relation to PCA and add further insight to understanding PCA molecular pathways

Copy Number Profiles of Prostate Cancer in Men of Middle Eastern Ancestry.

Our knowledge of prostate cancer (PCa) genomics mainly reflects European (EUR) and Asian (ASN) populations. Our understanding of the influence of Middle Eastern (ME) and African (AFR) ancestry on the mutational profiles of prostate cancer is limited. To characterize genomic differences between ME, EUR, ASN, and AFR ancestry, fluorescent in situ hybridization (FISH) studies for NKX3-1 deletion and MYC amplification were carried out on 42 tumors arising in individuals of ME ancestry. These were supplemented by analysis of genome-wide copy number profiles of 401 tumors of all ancestries. FISH results of NKX3-1 and MYC were assessed in the ME cohort and compared to other ancestries. Gene level copy number aberrations (CNAs) for each sample were statistically compared between ancestry groups. NKX3-1 deletions by FISH were observed in 17/42 (17.5%) prostate tumors arising in men of ME ancestry, while MYC amplifications were only observed in 1/42 (2.3%). Using CNAs called from arrays, the incidence of NKX3-1 deletions was significantly lower in ME vs. other ancestries (20% vs. 52%; p = 2.3 × 10-3). Across the genome, tumors arising in men of ME ancestry had fewer CNAs than those in men of other ancestries (p = 0.014). Additionally, the somatic amplification of 21 specific genes was more frequent in tumors arising in men of ME vs. EUR ancestry (two-sided proportion test; Q &lt; 0.05). Those included amplifications in the glutathione S-transferase family on chromosome 1 (GSTM1, GSTM2, GSTM5) and the IQ motif-containing family on chromosome 3 (IQCF1, IQCF2, IQCF13, IQCF4, IQCF5, IQCF6). Larger studies investigating ME populations are warranted to confirm these observations

Decreased ATM Protein Expression Is Substantiated with PTEN Loss in Defining Aggressive Phenotype of Prostate Cancer Associated with Lethal Disease

Background: Ataxia Telangiectasia Mutated (ATM) serine/threonine protein kinase is a known tumor suppressor, involved in DNA damage repair. It has prognostic and predictive therapeutic implications and is associated with aggressive prostate cancer (PCa). Objective: To investigate the prognostic value of ATM protein expression in PCa patients and assessed the combined value of ATM, ERG, and PTEN status. Design, setting, and participants: This study consisted of 303 patients with incidental, locally advanced, and castrate-resistant PCa by transurethral resection of the prostate (TURP). Outcome measurements and statistical analysis: TURP samples from 303 PCa patients were assessed by immunohistochemistry (IHC for ATM, ERG, and PTEN. Individual and combined marker status were correlated with International Society of Urological Pathology Gleason grade group, overall survival (OS), and PCa-specific mortality (PCSM). Results and limitations: Decreased ATM expression (negative/weak intensity) occurred in 164/303 (54.1%) patients, and was associated with shorter OS and higher PCSM (p = 0.015 and p = 0.001, respectively). Negative/weak ATM expression was significantly associated with PCSM with a hazard ratio of 2.09 (95% confidence interval 1.34–3.27, p = 0.001). Assessment of Combined ATM/PTEN expression showed improved prognostic power to predict OS and PCSM, independent of Gleason grade groups. Conclusions: Decreased ATM protein expression is associated with poor outcomes in advanced PCa patients. Patients with combined low ATM/PTEN negative expression are at the highest risk for reduced OS and PCSM. Assessing the combined status of ATM/PTEN by IHC in PCa patients may aid in risk stratification relative to OS and PCSM. Moreover, since ATM plays an integral role in DNA damage response pathways, future studies will enhance our understanding of how outcomes of patients with altered ATM and PTEN expression can be improved further with poly-ADP ribose polymerase inhibitors (PARPi), combinations of PARPi and androgen receptor–targeted therapies, as well as platinum-based chemotherapies. Patient summary: Lower ATM intensity is associated with increased cancer-specific mortality in prostate cancer patients. Patients with lower ATM and PTEN negative expression showed decreased overall survival and increased cancer mortality compared with controls

Copy Number Profiles of Prostate Cancer in Men of Middle Eastern Ancestry.

Our knowledge of prostate cancer (PCa) genomics mainly reflects European (EUR) and Asian (ASN) populations. Our understanding of the influence of Middle Eastern (ME) and African (AFR) ancestry on the mutational profiles of prostate cancer is limited. To characterize genomic differences between ME, EUR, ASN, and AFR ancestry, fluorescent in situ hybridization (FISH) studies for NKX3-1 deletion and MYC amplification were carried out on 42 tumors arising in individuals of ME ancestry. These were supplemented by analysis of genome-wide copy number profiles of 401 tumors of all ancestries. FISH results of NKX3-1 and MYC were assessed in the ME cohort and compared to other ancestries. Gene level copy number aberrations (CNAs) for each sample were statistically compared between ancestry groups. NKX3-1 deletions by FISH were observed in 17/42 (17.5%) prostate tumors arising in men of ME ancestry, while MYC amplifications were only observed in 1/42 (2.3%). Using CNAs called from arrays, the incidence of NKX3-1 deletions was significantly lower in ME vs. other ancestries (20% vs. 52%; p = 2.3 × 10-3). Across the genome, tumors arising in men of ME ancestry had fewer CNAs than those in men of other ancestries (p = 0.014). Additionally, the somatic amplification of 21 specific genes was more frequent in tumors arising in men of ME vs. EUR ancestry (two-sided proportion test; Q &lt; 0.05). Those included amplifications in the glutathione S-transferase family on chromosome 1 (GSTM1, GSTM2, GSTM5) and the IQ motif-containing family on chromosome 3 (IQCF1, IQCF2, IQCF13, IQCF4, IQCF5, IQCF6). Larger studies investigating ME populations are warranted to confirm these observations