scholarly journals Shoe–Floor Interactions in Human Walking With Slips: Modeling and Experiments

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Mitja Trkov ◽  
Jingang Yi ◽  
Tao Liu ◽  
Kang Li
Keyword(s):  
Experimental Studies ◽  
Human Walking ◽  
Force Distribution ◽  
Computational Approaches ◽  
Modeling Analysis ◽  
Increased Risk ◽  
Model Predictions ◽  
Modeling And Experiments ◽  
Deformation Measurements ◽  
Tribological Parameters

Shoe–floor interactions play a crucial role in determining the possibility of potential slip and fall during human walking. Biomechanical and tribological parameters influence the friction characteristics between the shoe sole and the floor and the existing work mainly focus on experimental studies. In this paper, we present modeling, analysis, and experiments to understand slip and force distributions between the shoe sole and floor surface during human walking. We present results for both soft and hard sole material. The computational approaches for slip and friction force distributions are presented using a spring-beam networks model. The model predictions match the experimentally observed sole deformations with large soft sole deformation at the beginning and the end stages of the stance, which indicates the increased risk for slip. The experiments confirm that both the previously reported required coefficient of friction (RCOF) and the deformation measurements in this study can be used to predict slip occurrence. Moreover, the deformation and force distribution results reported in this study provide further understanding and knowledge of slip initiation and termination under various biomechanical conditions.

Mechanisms underlying heart failure in type 2 diabetes mellitus

2019 ◽  
pp. 37-39
Keyword(s):  
Diabetes Mellitus ◽  
Heart Failure ◽  
Experimental Studies ◽  
Vascular Complications ◽  
Molecular Alterations ◽  
Increased Risk ◽  
Cardioprotective Effects ◽  
Underlying Mechanisms ◽  
Cardio Vascular

The prevalence of heart failure is markedly increased in individuals with diabetes mellitus. Numerous observational studies suggest that this increased risk for heart failure can be attributed to exacerbated vascular complications and the presence of increased risk factors in diabetic subjects. In addition, experimental studies revealed the presence of a number of distinct molecular alterations in the myocardium that occur independently of vascular disease and hypertension. Many of these molecular alterations are similarly observed in failing hearts of nondiabetic patients and have thus been proposed to contribute to the increased risk for heart failure in diabetes. The interest in understanding the underlying mechanisms of impaired cardio- vascular outcomes in diabetic individuals has much increased since the demonstration of cardioprotective effects of SGLT-2 inhibitors and GLP-1 receptor agonists in recent clinical trials. The current review therefore summarizes the distinct mechanisms that have been proposed to increase the risk for heart failure in diabetes mellitus.

scholarly journals 491. Aerosol-Generating Medical Procedures: Transmission of SARS-CoV-2 and Emerging Viruses

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S312-S312
Author(s):  
Seth D Judson ◽  
Vincent J Munster
Keyword(s):  
High Risk ◽  
Severe Disease ◽  
Experimental Studies ◽  
Virus Transmission ◽  
Nosocomial Transmission ◽  
Medical Procedures ◽  
Emerging Viruses ◽  
Zoonotic Viruses ◽  
Increased Risk ◽  
Hospital Acquired

Abstract Background During the pandemic of coronavirus disease 2019 (COVID-19), many questions arose regarding risks for hospital-acquired or nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Aerosol generating medical procedures (AGMPs), techniques that can generate infectious, virus-laden aerosols, could potentially amplify transmission among healthcare workers (HCWs). Thus, it was widely recommended that HCWs use airborne precautions when performing AGMPs. However, in clinical settings it is often unclear what procedures constitute AGMPs and how the risk varies by procedure or pathogen. We set out to further define AGMPs and assess the risk for nosocomial transmission of SARS-CoV-2 and other high-risk viruses via AGMPs. Methods We identified potential AGMPs and emerging viruses that were high-risk for nosocomial transmission through reviewing experimental and clinical data. Potential AGMPs were those associated with previous virus transmission or mechanically capable of transmission. High-risk viruses were defined as those that cause severe disease in humans for which limited therapies or interventions exist, are infectious via aerosols in humans or non-human primates (NHPs), found in the respiratory tract of infected humans or NHPs, and had previous evidence of nosocomial transmission. Results We identified multiple potential AGMPs, which could be divided into those that generate aerosols or induce a patient to form aerosols, as well as eight families of high-risk viruses. All of the viruses were emerging zoonotic RNA viruses. In the family Coronaviridae, we identified potential evidence for SARS-CoV-1, MERS-CoV, and SARS-CoV-2 transmission via AGMPs. SARS-CoV-1 and SARS-CoV-2 were also found to be similarly stable when aerosolized. Conclusion Multiple emerging zoonotic viruses pose a high risk for nosocomial transmission through a variety of AGMPs. Given the similar stability of SARS-CoV-2 with SARS-CoV-1 when aerosolized and prior nosocomial transmission of SARS-CoV-1 via AGMPs, we suspect that certain AGMPs pose an increased risk for SARS-CoV-2 transmission. Additional experimental studies and on-site clinical sampling during AGMPs are necessary to further risk stratify AGMPs. Disclosures All Authors: No reported disclosures

Ball Grid Array Thermomechanical Response During Reflow Assembly

1996 ◽  
Vol 118 (4) ◽  
pp. 214-222 ◽  
Author(s):  
T. E. Voth ◽  
T. L. Bergman
Keyword(s):  
Process Model ◽  
Experimental Studies ◽  
Ball Grid Array ◽  
Mechanical Processing ◽  
Processing Conditions ◽  
System Behavior ◽  
Reflow Soldering ◽  
Thermomechanical Response ◽  
Model Predictions ◽  
Representative System

The thermomechanical response of ball-grid array assemblies during reflow soldering is considered here. Experiments are performed to investigate the thermomechanical response of a representative system and the results are used to validate a numerical model of system behavior. The conclusions drawn from the experimental studies are used to guide development of a process model capable of describing more realistic BGA soldering scenarios. Process model predictions illustrate the system’s thermomechanical response to thermal and mechanical processing conditions, as well as component properties. High thermal conductivity assemblies show the greatest sensitivity to mechanical loading conditions.

Since blood transfusion is linked to the magnitude of the surgical procedure, comparing transfused patients to untransfused patients will always be confounded by infection risks due to factors related to the procedure. To control for these factors one must compare patients transfused with red cells from different sources or prepared in a manner which minimize infection risk. Patients transfused with homologous blood have infection rates several fold higher than recipients of equal values of autologous blood undergoing the same operative procedure (20-23). Homologous blood recipients have significantly longer hospital stays attributed to treating infections. The cost of a blood transfusion exceeds the cost of collection, storage and administration because of transfusion's association with length of stay. In this era of cost-containment the association with prolonged stay may ultimately curtail the use of blood. Homologous blood can be filtered to remove donor leukocytes which may be contributing to immune suppression and infection risk. A prospective randomized trial comparing the infection rates among colorectal cancer patients receiving filtered and unfiltered blood has been conducted (9). There were 17 infectious complications among the 56 recipients of whole blood and one infectious complication among the 48 recipients of filtered blood. Infections were prevented by the seemingly simplistic addition of a $25/filter to every bag of blood transfused. These clinical studies are very convincing: homologous blood transfusion is associated with increased risk of infection in every clinical situation examined. In multivariate analyses transfusion was a significant predictor of infection after consideration of other variables measured and in the majority of those studies transfusion was the single most significant factor. Patients receiving homologous blood exhibited an incidence of infectious complications that was approximately four times higher than patients receiving autologous blood. The association of transfusion with infection is found among patients undergoing surgery for cardiac, orthopedic and gastrointestinal disorders and for trauma as well as among unoperated patients transfused for bums and gastrointestinal bleeding. The observation that nosocomial infections are increased in these studies argues strongly that the association of transfusion with infection is not simply a reflection of transfusion as a marker of tissue destruction and contamination. Infections that develop in transfused patients away from the site of trauma or in the absence of trauma, cannot be attributed to the quantity of tissue destroyed or to the degree of bacterial contamination. Filtered blood can remove leukocytes and prevent postoperative infections. Since filtering blood can significantly reduce the incidence of infection among transfused patients, all transfused blood will be passing through filters in the very near future. EXPERIMENTAL STUDIES RELATING BLOOD TRANSFUSION TO INCREASED RISK OF INFECTION Patients are extremely heterogeneous and even in prospective randomized trials, factors which influence patients' participation affect the outcome despite double-blinding and randomization. In animal studies using syngeneic strains with identical housing, lighting, access to food and water, control over the extent of injury, use of antibiotics and exposure to other variables the influence of a single variable such as blood transfusion can be measured. Dr. Waymack's laboratory has intensively studied parameters which interact with transfusion in

1995 ◽  
pp. 296-296
Keyword(s):  
Blood Transfusion ◽  
Autologous Blood ◽  
Experimental Studies ◽  
Infection Risk ◽  
Infectious Complications ◽  
Risk Of Infection ◽  
Infection Rates ◽  
Homologous Blood ◽  
Increased Risk ◽  
The Cost

scholarly journals Hyperhomocysteinemia in developing age and nutritional aspects of folates: an early cardiovascular risk factor

2016 ◽  
Vol 66 (4) ◽  
Author(s):  
Giuseppe Caramia ◽  
Romualdo Belardinelli
Keyword(s):  
Cardiovascular Risk ◽  
Endothelial Function ◽  
Plasma Levels ◽  
Experimental Studies ◽  
Oral Supplementation ◽  
Increased Risk ◽  
Artery Disease ◽  
Ischemic Events ◽  
Ischemic Encephalopathy ◽  
Documented Coronary Artery Disease

elevated plasma levels of homocysteine are associated with an increased risk of atherosclerosis and cardiovascular ischemic events. Despite this evidence, however, there are still concerns about the mechanisms(s) by which homocysteine exerts its pro-atherogenic effect, and it is unclear whether the decreased plasma levels of homocysteine through diet or drugs may be paralleled by a reduction in cardiovascular risk. Experimental studies have shown that many possible mechanisms are implicated in the pro-atherogenic effect of homocysteine. Endothelial function is altered in subjects with hyperhomocysteinemia, and endothelial dysfunction is correlated with plasma levels of homocysteine. Exercise training reduces plasma levels of homocysteine and improves endothelial function, however without evidence of a better outcome. Larger studies are needed in order to demonstrate that the reduction of plasma levels of homocysteine by oral supplementation with folates and vitamins B6 and B12 translates into a decreased incidence of ischemic events, in particular in patients with documented coronary artery disease and ischemic encephalopathy.

scholarly journals Sodium Sensitivity, Sodium Resistance, and Incidence of Hypertension

Hypertension ◽  
2021 ◽  
Author(s):  
Jiang He ◽  
Jian-Feng Huang ◽  
Changwei Li ◽  
Jing Chen ◽  
Xiangfeng Lu ◽  
...  
Keyword(s):  
Sodium Intake ◽  
Experimental Studies ◽  
Dietary Sodium ◽  
Cross Sectional ◽  
Incident Hypertension ◽  
High Sodium ◽  
Sodium Sensitivity ◽  
Sodium Diet ◽  
Low Sodium ◽  
Increased Risk

Cross-sectional studies have reported that high sodium sensitivity is more common among individuals with hypertension. Experimental studies have also reported various animal models with sodium-resistant hypertension. It is unknown, however, whether sodium sensitivity and resistance precede the development of hypertension. We conducted a feeding study, including a 7-day low-sodium diet (1180 mg/day) followed by a 7-day high-sodium diet (7081 mg/day), among 1718 Chinese adults with blood pressure (BP) <140/90 mm Hg. We longitudinally followed them over an average of 7.4 years. Three BP measurements and 24-hour urinary sodium excretion were obtained on each of 3 days during baseline observation, low-sodium and high-sodium interventions, and 2 follow-up studies. Three trajectories of BP responses to dietary sodium intake were identified using latent trajectory analysis. Mean (SD) changes in systolic BP were −13.7 (5.5), −4.9 (3.0), and 2.4 (3.0) mm Hg during the low-sodium intervention and 11.2 (5.3), 4.4 (4.1), and −0.2 (4.1) mm Hg during the high-sodium intervention ( P <0.001 for group differences) in high sodium-sensitive, moderate sodium-sensitive, and sodium-resistant groups, respectively. Compared with individuals with moderate sodium sensitivity, multiple-adjusted odds ratios (95% CIs) for incident hypertension were 1.43 (1.03–1.98) for those with high sodium sensitivity and 1.43 (1.03–1.99) for those with sodium resistance ( P =0.006 for nonlinear trend). Furthermore, a J-shaped association between systolic BP responses to sodium intake and incident hypertension was identified ( P <0.001). Similar results were observed for diastolic BP. Our study indicates that individuals with either high sodium sensitivity or sodium resistance are at an increased risk for developing hypertension.

scholarly journals TSH suppressive therapy and bone

2020 ◽  
Vol 9 (7) ◽  
pp. R158-R172 ◽  
Author(s):  
Alessandro Brancatella ◽  
Claudio Marcocci
Keyword(s):  
Bone Loss ◽  
Postmenopausal Women ◽  
Bone Cells ◽  
Trabecular Bone Score ◽  
Experimental Studies ◽  
Bone Architecture ◽  
Tsh Receptor ◽  
Suppressive Therapy ◽  
Mineral Density ◽  
Increased Risk

Thyroid hormones stimulate bone turnover in adults by increasing osteoclastic bone resorption. TSH suppressive therapy is usually applied in patients with differentiated thyroid cancer (DTC) to improve the disease outcome. Over the last decades several authors have closely monitored the potential harm suffered by the skeletal system. Several studies and meta-analyses have shown that chronic TSH suppressive therapy is safe in premenopausal women and men. Conversely, in postmenopausal women TSH suppressive therapy is associated with a decrease of bone mineral density, deterioration of bone architecture (quantitative CT, QCT; trabecular bone score, TBS), and, possibly, an increased risk of fractures. The TSH receptor is expressed in bone cells and the results of experimental studies in TSH receptor knockout mice and humans on whether low TSH levels, as opposed to solely high thyroid hormone levels, might contribute to bone loss in endogenous or exogenous thyrotoxicosis remain controversial. Recent guidelines on the use of TSH suppressive therapy in patients with DTC give value not only to its benefit on the outcome of the disease, but also to the risks associated with exogenous thyrotoxicosis, namely menopause, osteopenia or osteoporosis, age >60 years, and history of atrial fibrillation. Bone health (BMD and/or preferably TBS) should be evaluated in postmenopausal women under chronic TSH suppressive therapy or in those patients planning to be treated for several years. Antiresorptive therapy could also be considered in selected cases (increased risk of fracture or significant decline of BMD/TBS during therapy) to prevent bone loss.

CFD Study of Ship-to-Bank Interaction

2017 ◽  
Vol Vol 159 (A3) ◽  
Author(s):  
Y K Kim ◽  
E Y K Ng
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Field ◽  
Physical Phenomenon ◽  
Experimental Studies ◽  
Container Ship ◽  
Confined Water ◽  
Water Effect ◽  
Computational Approaches ◽  
Shallow Water Effect

Ship-to-bank interaction is a complex physical phenomenon that involves not only in the asymmetric pressure field near banks or channels but also shallow water effect. Traditionally many experimental studies were carried out in this field. As numerical method is getting popular, there were various computational approaches as well. In this study, flow around a container ship in confined water is investigated with the open source CFD (Computational Fluid Dynamics) toolbox, OpenFOAM. Computations with several bank arrangements and different settings are performed. The OpenFOAM results are also compared to experiment results for validation.

Experimental Study of Wave Force Distribution on a Monopile Structure

2018 ◽  
Author(s):  
Malene H. Vested ◽  
Stefan Carstensen ◽  
Erik Damgaard Christensen
Keyword(s):  
Experimental Studies ◽  
Cost Effective ◽  
Wave Force ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Force Distribution ◽  
Wave Forces ◽  
Total Force ◽  
Wave Flume ◽  
Effective Manner

As the demand for offshore wind energy continues to grow, the strive to understand the wave forces acting on the substructure of the wind turbines continues. In regard to wind turbine design, it is vital to consider not only the total wave force, but also the local wave forces. Local forces are particularly important for the design of secondary structures as e.g. mooring platforms. Typically, however, experimental studies mainly concern total forces or idealized local forces. We present here a rather simple way to measure local forces along a model monopile. The study is conducted in a wave flume of 28 m in length, in which waves are generated by a piston-type wave maker at a water depth of 0.515 m and shoal onto a bed of slope 1:25. A model monopile is installed and subjected to forcing from a series of both regular and irregular waves. In the experimental set-up, the model monopile is fixed at the bottom and the top and consists of seven independent cylindrical sections. The cylindrical sections are connected by force transducers which measure local shear, and so the associated local forces may be determined. The measured local forces are compared to the force distribution given by Morisons equation combined with linear theory and Wheeler stretching, which is a force estimate commonly used in the industry. This study shows that the total force is rather well captured by Morison’s equation. The force distribution estimated from Morison’s equation, however, shows larger discrepancies from the measured forces. This encourages for further measurements. In this study, we show that it is possible to measure force distribution on a model monopile in a simple and cost-effective manner. The aim is here to demonstrate the method and we will later present a larger body of work associated with the outcome of the measurements.

scholarly journals Pre-diagnostic leukocyte mitochondrial DNA copy number and colorectal cancer risk

2019 ◽  
Vol 40 (12) ◽  
pp. 1462-1468 ◽  
Author(s):  
Keming Yang ◽  
Xin Li ◽  
Michele R Forman ◽  
Patrick O Monahan ◽  
Bret H Graham ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Mitochondrial Dna ◽  
Copy Number ◽  
Quantitative Polymerase Chain Reaction ◽  
Conditional Logistic Regression ◽  
Experimental Studies ◽  
Inverse Association ◽  
Mitochondrial Dna Copy Number ◽  
Increased Risk

Abstract Mitochondrial DNA (mtDNA) is susceptible to oxidative stress and mutation. Few epidemiological studies have assessed the relationship between mtDNA copy number (mtDNAcn) and risk of colorectal cancer (CRC), with inconsistent findings. In this study, we examined the association between pre-diagnostic leukocyte mtDNAcn and CRC risk in a case–control study of 324 female cases and 658 matched controls nested within the Nurses’ Health Study (NHS). Relative mtDNAcn in peripheral blood leukocytes was measured by quantitative polymerase chain reaction-based assay. Conditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association of interest. Results showed lower log-mtDNAcn was significantly associated with increased risk of CRC, in a dose-dependent relationship (P for trend &lt; 0.0001). Compared to the fourth quartile, multivariable-adjusted OR [95% confidence interval (CI)] was 1.10 (0.69, 1.76) for the third quartile, 1.40 (0.89, 2.19) for the second quartile and 2.19 (1.43, 3.35) for the first quartile. In analysis by anatomic subsite of CRC, we found a significant inverse association for proximal colon cancer [lowest versus highest quartile, multivariable-adjusted OR (95% CI) = 3.31 (1.70, 6.45), P for trend = 0.0003]. Additionally, stratified analysis according to the follow-up time since blood collection showed that the inverse association between mtDNAcn and CRC remained significant among individuals with ≥ 5 years’ follow-up, and marginally significant among those with ≥ 10 years’ follow-up since mtDNAcn testing, suggesting that mtDNAcn may serve as a long-term predictor for risk of CRC. In conclusion, pre-diagnostic leukocyte mtDNAcn was inversely associated with CRC risk. Further basic experimental studies are needed to explore the underlying biological mechanisms linking mtDNAcn to CRC carcinogenesis.

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