136 research outputs found

    Dynamic Analysis of High Frequency Vibro-Impact Drilling

    Get PDF
    Vibro-impact drilling system modelling is a research and results of the selected models which is more complex model known as three mass model. As we know that this model is invented to prove the dynamic relationship between the drilled formation and drill bit. The static force, excitation frequency and the excitation amplitude is the main three main control parameters. The investigation ensures that rate of progression is varied by the three main parameters. Higher the static force and excitation amplitude, the best progression rate can be achieved. Thus, in this case, the static force is linear with excitation of amplitude. However, the lower value of excitation and increases in excitation of frequency with the decrease in static force, the result shows zero progression rate. Thus, this concludes the zero progression rate at higher excitation frequency for this models. As based on analysis, the model uses the resonance enhanced drilling (RED) technique for forming resonance state by using the adjustable high dynamic stress to improve the rate of progression. The simulation for the vibro-impact drilling motion is obtained by solving the equation of motion using MATLAB software

    Dynamic Analysis of High Frequency Vibro-Impact Drilling

    Get PDF
    Vibro-impact drilling system modelling is a research and results of the selected models which is more complex model known as three mass model. As we know that this model is invented to prove the dynamic relationship between the drilled formation and drill bit. The static force, excitation frequency and the excitation amplitude is the main three main control parameters. The investigation ensures that rate of progression is varied by the three main parameters. Higher the static force and excitation amplitude, the best progression rate can be achieved. Thus, in this case, the static force is linear with excitation of amplitude. However, the lower value of excitation and increases in excitation of frequency with the decrease in static force, the result shows zero progression rate. Thus, this concludes the zero progression rate at higher excitation frequency for this models. As based on analysis, the model uses the resonance enhanced drilling (RED) technique for forming resonance state by using the adjustable high dynamic stress to improve the rate of progression. The simulation for the vibro-impact drilling motion is obtained by solving the equation of motion using MATLAB software

    The Risk of Recurrence in Breast Cancer Patients Treated with Tamoxifen: Polymorphisms of CYP2D6 and ABCB1

    Get PDF
    CYP2D6 plays a major role in the metabolism of tamoxifen, and polymorphism of Pglycoprotein has been associated with resistance of many drug therapies. This study investigates the clinical impact of genetic variants of CYP2D6 and ABCB1 in breast cancer patients treated with tamoxifen. Blood samples from 95 breast cancer patients treated with tamoxifen were collected and genotyped for CYP2D6 and ABCB1 variants using allele-specific PCR method. Recurrence risks were calculated using Kaplan–Meier analysis and compared using the log-rank test. Patients carrying CYP2D6*10/*10 and heterozygous null allele (IM) showed higher risks of developing recurrence and metastasis (OR 13.14; 95% CI 1.57–109.94; P=0.004) than patients with CYP2D6*1/*1 and *1/*10 genotypes. Patients with homozygous CC genotypes of ABCB1 C3435T showed a shorter time to recurrence. Patients who were CYP2D6 IM and homozygous CC genotype of C3435T have statistically significant higher risks of recurrence (P=0.002). Similarly, median time to recurrence in these patients was only 12 months (95% CI=0.79–23.2) compared to those without this combination which was 48 months (95% CI=14.7–81.2). Patients with CYP2D6 IM and homozygous CC genotype of ABCB1 C3435T have shorter times to recurrence. The results confirmed the findings of previous studies and support FDA recommendation to perform pre-genotyping in patients before the choice of therapy is determined in breast cancer patients

    Analysis of common genetic variation and rare CNVs in the Australian Autism Biobank.

    Full text link
    BackgroundAutism spectrum disorder (ASD) is a complex neurodevelopmental condition whose biological basis is yet to be elucidated. The Australian Autism Biobank (AAB) is an initiative of the Cooperative Research Centre for Living with Autism (Autism CRC) to establish an Australian resource of biospecimens, phenotypes and genomic data for research on autism.MethodsGenome-wide single-nucleotide polymorphism genotypes were available for 2,477 individuals (after quality control) from 546 families (436 complete), including 886 participants aged 2 to 17 years with diagnosed (n = 871) or suspected (n = 15) ASD, 218 siblings without ASD, 1,256 parents, and 117 unrelated children without an ASD diagnosis. The genetic data were used to confirm familial relationships and assign ancestry, which was majority European (n = 1,964 European individuals). We generated polygenic scores (PGS) for ASD, IQ, chronotype and height in the subset of Europeans, and in 3,490 unrelated ancestry-matched participants from the UK Biobank. We tested for group differences for each PGS, and performed prediction analyses for related phenotypes in the AAB. We called copy-number variants (CNVs) in all participants, and intersected these with high-confidence ASD- and intellectual disability (ID)-associated CNVs and genes from the public domain.ResultsThe ASD (p = 6.1e-13), sibling (p = 4.9e-3) and unrelated (p = 3.0e-3) groups had significantly higher ASD PGS than UK Biobank controls, whereas this was not the case for height-a control trait. The IQ PGS was a significant predictor of measured IQ in undiagnosed children (r = 0.24, p = 2.1e-3) and parents (r = 0.17, p = 8.0e-7; 4.0% of variance), but not the ASD group. Chronotype PGS predicted sleep disturbances within the ASD group (r = 0.13, p = 1.9e-3; 1.3% of variance). In the CNV analysis, we identified 13 individuals with CNVs overlapping ASD/ID-associated CNVs, and 12 with CNVs overlapping ASD/ID/developmental delay-associated genes identified on the basis of de novo variants.LimitationsThis dataset is modest in size, and the publicly-available genome-wide-association-study (GWAS) summary statistics used to calculate PGS for ASD and other traits are relatively underpowered.ConclusionsWe report on common genetic variation and rare CNVs within the AAB. Prediction analyses using currently available GWAS summary statistics are largely consistent with expected relationships based on published studies. As the size of publicly-available GWAS summary statistics grows, the phenotypic depth of the AAB dataset will provide many opportunities for analyses of autism profiles and co-occurring conditions, including when integrated with other omics datasets generated from AAB biospecimens (blood, urine, stool, hair)

    Interactions between the lipidome and genetic and environmental factors in autism.

    Get PDF
    Autism omics research has historically been reductionist and diagnosis centric, with little attention paid to common co-occurring conditions (for example, sleep and feeding disorders) and the complex interplay between molecular profiles and neurodevelopment, genetics, environmental factors and health. Here we explored the plasma lipidome (783 lipid species) in 765 children (485 diagnosed with autism spectrum disorder (ASD)) within the Australian Autism Biobank. We identified lipids associated with ASD diagnosis (n = 8), sleep disturbances (n = 20) and cognitive function (n = 8) and found that long-chain polyunsaturated fatty acids may causally contribute to sleep disturbances mediated by the FADS gene cluster. We explored the interplay of environmental factors with neurodevelopment and the lipidome, finding that sleep disturbances and unhealthy diet have a convergent lipidome profile (with potential mediation by the microbiome) that is also independently associated with poorer adaptive function. In contrast, ASD lipidome differences were accounted for by dietary differences and sleep disturbances. We identified a large chr19p13.2 copy number variant genetic deletion spanning the LDLR gene and two high-confidence ASD genes (ELAVL3 and SMARCA4) in one child with an ASD diagnosis and widespread low-density lipoprotein-related lipidome derangements. Lipidomics captures the complexity of neurodevelopment, as well as the biological effects of conditions that commonly affect quality of life among autistic people

    Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

    Get PDF
    Background: Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods: The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results: A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion: Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)

    Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study

    Get PDF
    We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05-1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4-7 days or ≥ 8 days of 1.25 (1.04-1.48), p = 0.015 and 1.31 (1.11-1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care

    The effect of a robotics program on primary school students’ attitude towards science and problem solving

    Get PDF
    This study was conducted to see the effect of robotics program on primary school students’ attitude towards science and problem solving. Students interest towards science and mathematics already lacking as early of primary school because of less engagement in teaching and learning. There are less hands on teaching in primary school compare to secondary and tertiary education. This has lead to primary school students’ attitude towards science and problem solving lacking. Besides that, studies related to Integrated STEM Approach with students attitude at primary school level are still lacking and it is largely focused on higher institutions. Hence, this study has been carried out to see the effect of robotics program on primary school students’ attitude towards science and problem solving. This study uses a quantitative approach method with a quasi-experimental design involving treatment group (Malacca schools students) and control group (Selangor schools students). A total of 374 primary school students from year six under Ministry of Education Malaysia from Malacca and Selangor were involved in this study. Two questionnaires were used, namely the Test of Science Related Attitudes (TOSRA) was used to measure the attitude towards science of students as well as the Solving Problem Survey questionnaire on attitude towards problem solving. The statistical tests performed were the Repeated Analysis of variance (ANOVA), and One-way Analysis of Covariance (ANCOVA) at a significant level of p <0.05. Researcher looked at the Mauchly’s test for Sphericity as well as subject effect size because the measurements were performed at three different time periods (pre-test, post-test 1 and post-test 2). The results of the analysis showed that the treatment group (Malacca schools students) and control group showed significant changes in the three time periods. Yet the researcher looked at the subject effect size value, which showed the treatment group was higher than the control group. For attitude towards science and problem solving experiment group showed significant changes when compared with the control group.It is suggested that the robotics program can be applied to see improvement in primary school students attitude towards science and problem solving. However, this method needs to be tested using other attitudes so that the effect of robotics program can be seen more holistically
    corecore