The Stability of Veins Under Torsion

2012 ◽  
Author(s):  
Justin R. Garcia ◽  
Hai-Chao Han
Keyword(s):  
Diabetes Mellitus ◽  
Health Risks ◽  
Mechanical Stability ◽  
Thrombus Formation ◽  
Body Movement ◽  
Critical Value ◽  
The Body ◽  
Clinical Interest ◽  
The Stability

Twisted veins are observed throughout the body and are often associated with health risks such as hypertension and diabetes mellitus [1]. Recently, it has been shown that veins will buckle and become tortuous when lumen pressure exceeds a critical value [2]. However, veins also undergo twist deformations in vivo due to body movement, vein grafting, and microanastomosis procedures which may lead to reduced patency, kinking, and thrombus formation [3, 4]. In spite of this, little data is available regarding the stability of veins when subject to twist deformations. Therefore, it is of clinical interest to investigate the mechanical stability of veins under torsion.

ORIENTATION OF SYMMETRIC BODIES FALLING IN A SECOND-ORDER LIQUID AT NONZERO REYNOLDS NUMBER

2002 ◽  
Vol 12 (11) ◽  
pp. 1653-1690 ◽  
Author(s):  
GIOVANNI P. GALDI ◽  
ASHWIN VAIDYA ◽  
MILAN POKORNÝ ◽  
DANIEL D. JOSEPH ◽  
JIMMY FENG
Keyword(s):  
Prolate Spheroid ◽  
Critical Value ◽  
Second Order ◽  
The Body ◽  
Body Of Revolution ◽  
Translational Velocity ◽  
Homogeneous Body ◽  
First Order ◽  
The Stability ◽  
Elasticity Number

We study the steady translational fall of a homogeneous body of revolution around an axis a, with fore-and-aft symmetry, in a second-order liquid at nonzero Reynolds (Re) and Weissenberg (We) numbers. We show that, at first order in these parameters, only two orientations are allowed, namely, those with a either parallel or perpendicular to the direction of the gravity g. In both cases the translational velocity is parallel to g. The stability of the orientations can be described in terms of a critical value E c for the elasticity number E = We/Re , where E c depends only on the geometric properties of the body, such as size or shape, and on the quantity (Ψ1 + Ψ2)/Ψ1, where Ψ1 and Ψ2 are the first and second normal stress coefficients. These results are then applied to the case when the body is a prolate spheroid. Our analysis shows, in particular, that there is no tilt-angle phenomenon at first order in Re and We.

On the Stability Analysis of the Human Spine

2003 ◽  
Author(s):  
M. El-Rich ◽  
A. Shirazi-Adl
Keyword(s):  
Stability Analysis ◽  
Material Handling ◽  
Muscle Activation ◽  
The Body ◽  
Abdominal Pressure ◽  
Human Spine ◽  
Manual Material Handling ◽  
The Stability ◽  
Force Relationship

The stability of the human spine in compression has attracted a considerable amount of attention in recent years. The passive ligamentous thoracolumbar and lumbar spines are known to exhibit large displacements or hypermobility (i.e., instability in an imperfect column) under compression loads <100N. Since such compression loads are only a small fraction of those supported by the spine even in regular daily activities, let aside the manual material handling tasks, the question arises as to how the spine is stablized in vivo? Various stabilizing mechanisms have been proposed and investigated; wrapping loading [Shirazi-Adl and Parnianpour, 2000], postural adaptations [Shirazi-Adl and parnianpor, 1999], intra-abdominal pressure [Cholewicki et al, 1999] and muscle activation/coactivation [Bergmark, 1989; Crisco and Panjabi, 1991]. In this work, a novel kinematics-based methad [Shirazi-Adl et al., 2002] is first applied to compute muscle forces and internal loads in standing postures under gravity with or without 200N loads held either on sides or close to the body in front. The stability of the system under given loads and prescribed postures is sudsequently examined using both linear bucking analysis based on the deformed configurations and nonlinear analysis while employing a liner stiffness-force relationship for muscules [Bergmark, 1989; Crico and Panjabi, 1991]. The relative accuracy of foregoing methods in stability analysis of some sample structures is also investigated. Moreover, the effect of co-activity on stability of the spine in neutral postures is studied.

scholarly journals Cancer cell–derived microparticles bearing P-selectin glycoprotein ligand 1 accelerate thrombus formation in vivo

2009 ◽  
Vol 206 (9) ◽  
pp. 1913-1927 ◽  
Author(s):  
Grace M. Thomas ◽  
Laurence Panicot-Dubois ◽  
Romaric Lacroix ◽  
Françoise Dignat-George ◽  
Dominique Lombardo ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Endothelial Cell ◽  
Cancer Cell ◽  
Bleeding Time ◽  
Thrombus Formation ◽  
Prevention Of Thrombosis ◽  
Living Mouse ◽  
Clinical Interest ◽  
Dependent Pathway

Recent publications have demonstrated the presence of tissue factor (TF)–bearing microparticles (MPs) in the blood of patients suffering from cancer. However, whether these MPs are involved in thrombosis remains unknown. We show that pancreatic and lung cancer cells produce MPs that express active TF and P-selectin glycoprotein ligand 1 (PSGL-1). Cancer cell–derived MPs aggregate platelets via a TF-dependent pathway. In vivo, cancer cell–derived MPs, but not their parent cells, infused into a living mouse accumulate at the site of injury and reduce tail bleeding time and the time to occlusion of venules and arterioles. This thrombotic state is also observed in mice developing tumors. In such mice, the amount of circulating platelet-, endothelial cell–, and cancer cell–derived MPs is increased. Endogenous cancer cell–derived MPs shed from the growing tumor are able to accumulate at the site of injury. Infusion of a blocking P-selectin antibody abolishes the thrombotic state observed after injection of MPs or in mice developing a tumor. Collectively, our results indicate that cancer cell–derived MPs bearing PSGL-1 and TF play a key role in thrombus formation in vivo. Targeting these MPs could be of clinical interest in the prevention of thrombosis and to limit formation of metastasis in cancer patients.

scholarly journals In vivo Approach: Potential Diuretic Activity of M. charantia Linn. on Alloxan Induced Albino Wistar Rats in Diabetes Mellitus

2020 ◽  
pp. 61-75
Author(s):  
Umesh B. Wahul ◽  
Ambadas S. Kadam ◽  
Laxmikant H. Kamble ◽  
Ayaz S. Ali
Keyword(s):  
Diabetes Mellitus ◽  
Wistar Rat ◽  
The Body ◽  
Alcoholic Extract ◽  
Diuretic Activity ◽  
Standard Drug ◽  
Spot Urine ◽  
Novel Approach ◽  
Insight Into

The screening of perfect diuretics for non –clinical utility in Diabetes mellitus is a relatively novel approach which gain insight into underlying the pathophysiological processes. This study aim to evaluate the diuretic effect of crude aqueous & alcoholic extract of M. charantia Linn. using Albino Wistar Rat model. The methodology of animal study includes the spectral analysis of Na+, K+, Cl-concentration against the body weight, this was done by spectrophotometry. In this study, the comparative observation of Diuretic activity with standard and extracted compound has shown that the estimated 24‐hour urine contains the Na+-3.82 g, 3.82 g, 3.92 g  and K+-1.35 g, 1.39 g, 1.48 gwt. For Vehicle control, Standard drug, and Extracted compound respectively. Which possess the favouring result means from the spot urine were 10.7±7.0 g/24 hand 3.9±2.1 g/24 h, respectively. Coefficients were 0.035, 0.022, 0.046 at (d±2SD=7.07 g, 4.42 gand 8.92 g) for sodium chloride and 0.068, 0.031, 0.046 at (d ± 2SD = 4.92 g, 2.31 g and 3.34 g) for potassium chloride. The present study guide formulation of non-clinical trials with statistical study to further measuring the claimed efficacy of M. charantia as a natural remedy for diabetes mellitus.

Abstract 17744: In Vivo Platelet Activation and Aspirin Responsiveness in Type 1 Diabetes Mellitus

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Francesco Zaccardi ◽  
Francesca Pagliaccia ◽  
Alessandro Rizzi ◽  
Giovanna Petrucci ◽  
Aida Habib ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Platelet Activation ◽  
Linear Trend ◽  
Glucose Monitoring ◽  
Glycemic Variability ◽  
Endothelial Damage ◽  
Low Dose Aspirin ◽  
Repeated Sampling ◽  
The Stability

Introduction: While reduced responsiveness to low-dose aspirin has been associated with type 2 diabetes mellitus (T2DM), aspirin responsiveness remains unexplored in T1DM. Hypothesis: We investigated in vivo platelet activation, as reflected by the urinary excretion of 11-dehydro-TXB2 (TXM) and platelet COX-1 inhibition, as assessed by serum TXB2 (sTXB2), in uncomplicated, normotensive, normolipidemic T1DM subjects on insulin therapy. Methods: Upon informed consent, we enrolled 40 T1DM patients (26M, age 35±11yr, disease duration 16±11yr, BMI 24±2 kg/m2) and 10 healthy controls (6M, age 33±7yr). In 9 patients we assessed the stability of TXM excretion on 3 different visits. Thirty-one patients and all controls were given 100 mg daily aspirin for 21 days, and urinary TXM and sTXB2 were measured before and 24h after stopping aspirin. To assess the influence of glycemic variability on aspirin response, 26 patients underwent continuous glucose monitoring (CGM) for the first 24h after drug withdrawal. Results: TXM excretion in T1DM was significantly higher than in controls (930 [659-1358] vs 568 [385-619] pg/mg creatinine; p<0.001) and quite stable across repeated sampling (p for linear trend = 0.755). By multivariate analysis, urinary TXM was associated with microalbuminuria (β=0.23; p=0.042) at baseline. The degree of inhibition at 24h after aspirin dosing was similar in T1DM and controls for both sTXB2 (98.2% vs 98.6%, p=0.607) and urinary TXM (68.8% vs 68.4%, p=0.962). CGM-derived mean and standard deviation glucose were not associated with sTXB2 or TXM inhibition at 24h. Conclusions: We conclude that enhanced platelet activation in T1DM is independent of glycemic control and associated with kidney/endothelial damage. Moreover, in contrast to T2DM, the response to aspirin is unchanged, suggesting that the metabolic disturbance per se is not responsible for altered pharmacodynamics.

scholarly journals Hypoglycemic Effects of Plant Flavonoids: A Review

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Foo Sok Yen ◽  
Chan Shu Qin ◽  
Sharryl Tan Shi Xuan ◽  
Puah Jia Ying ◽  
Hong Yi Le ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Blood Glucose ◽  
Antioxidant Activities ◽  
Diabetic Rats ◽  
The Body ◽  
High Blood Glucose ◽  
Glucose Levels ◽  
Multiple Organs

Diabetes mellitus is a metabolic disorder with chronic high blood glucose levels, and it is associated with defects in insulin secretion, insulin resistance, or both. It is also a major public issue, affecting the world's population. This disease contributes to long-term health complications such as dysfunction and failure of multiple organs, including nerves, heart, blood vessels, kidneys, and eyes. Flavonoids are phenolic compounds found in nature and usually present as secondary metabolites in plants, vegetables, and fungi. Flavonoids possess many health benefits such as anti-inflammatory and antioxidant activities, and naturally occurring flavonoids contribute to antidiabetic effects.Many studies conducted in vivo and in vitro have proven the hypoglycemic effect of plant flavonoids. A large number of studies showed that flavonoids hold positive results in controlling the blood glucose level in streptozotocin (STZ)-induced diabetic rats and further prevent the complications of diabetes. The future development of flavonoid-based drugs is believed to provide significant effects on diabetes mellitus and diabetes complication diseases. This review aims at summarizing the various types of flavonoids that function as hyperglycemia regulators such as inhibitors of α-glucosidase and glucose cotransporters in the body. This review article discusses the hypoglycemic effects of selected plant flavonoids namely quercetin, kaempferol, rutin, naringenin, fisetin, and morin. Four search engines, PubMed, Google Scholar, Scopus, and SciFinder, are used to collect the data.

scholarly journals Antioxidant Activity of Pigmented Rice and Impact on Health

JURNAL PANGAN ◽  
2019 ◽  
Vol 28 (1) ◽  
pp. 11-22
Author(s):  
Arfina Sukmawati Arifin
Keyword(s):  
Oxidative Stress ◽  
Diabetes Mellitus ◽  
Antioxidant Activity ◽  
Vascular Function ◽  
Healthy Lifestyle ◽  
Cell Damage ◽  
The Body ◽  
Food Sources

The high number of free radicals that are not balanced with the amount of antioxidants in the body triggers oxidative stress. Oxidative stress causes impaired vascular function, damage to proteins and lipids in membrane cell, and nucleic acid (DNA) mutations. Chronic cell damage has a negative effect on tissue that triggers various diseases such as neurodegenerative diseases (Alzheimer's, Parkinson's), cardiovascular diseases (hypertension, arteriosclerosis, and others), cataracts, retinal damage, maculopathy, rheumatoid arthritis, asthma, stroke, diabetes mellitus , immunodepression, cancer, aging, hyperoxia, dermatitis, and others. The application of a healthy lifestyle for example by consuming food sources of bioactive compounds can minimize health risks. Rice is the staple food of the Indonesian people. Some types of rice contain red and black pigments which are known to have high antioxidant activity compared to white rice. The pigment comes from anthocyanin and proanthocyanidin. Various studies in vitro and in vivo prove that anthocyanin and proantocyanidine act as antioxidants and potency as a preventative for various diseases such as cardiovascular, diabetes mellitus, and etc.

scholarly journals Evidence of the hypoglycemic capacity of some natural products for the alternative treatment of diabetes mellitus type 2

2020 ◽  
Vol 8 (16) ◽  
pp. 56-64
Author(s):  
Karla Guadalupe Perez-Avila ◽  
Cruz Vargas-De-León ◽  
José Antonio Morales-González ◽  
Eduardo Madrigal-Santillán
Keyword(s):  
Diabetes Mellitus ◽  
Natural Products ◽  
Alternative Treatment ◽  
The Body ◽  
In Vitro Assays ◽  
Glucose Levels ◽  
Natural Treatment ◽  
Treatment Of Diabetes

Diabetes mellitus is a disease that is characterized by the chronic presence of blood glucose levels caused by a defect in the secretion of insulin or in the action of this hormone in the body which must be treated integrally with a multidisciplinary approach. The natural treatment of this disease is a common practice around the world, especially in Latin America, there are several clinical studies, in vivo or in vitro assays that focus on assessing the hypoglycemic capacity of various natural products used empirically by the population for years for the phytotherapeutic treatment of the disease as well as the chemicals related to the mechanism of action that produces the hypoglycaemic effect. In the present article, a brief review of the evidence of the hypoglycemic capacity of some natural products for the alternative treatment of diabetes mellitus 2

scholarly journals Simulation of Motion Stability of Deformed Elongated Bodies Based on Variations of Angular Velocities in Roll

2019 ◽  
Vol 18 (3) ◽  
pp. 646-677
Author(s):  
Irina Romanova
Keyword(s):  
Angular Velocity ◽  
Body Movement ◽  
Stability Boundary ◽  
Complex Form ◽  
Passive Movement ◽  
The Body ◽  
Slip Angle ◽  
Motion Stability ◽  
Angular Velocities ◽  
The Stability

The class of moving objects, which are bodies of revolution, which for some reason have undergone irreversible deformations of the hull, is considered. The immediacy of the problem being studied has to do both with the need to study the dynamics of such objects and the insufficiency of the studies already conducted, which are mainly focused on the study of the effects of aeroelasticity or mass asymmetry and do not affect the dynamics of bodies with irreversible deformations. The problem of the motion stability of the considered objects, including the process of interaction of the longitudinal and lateral movements of the deformed body, is formulated. Particular attention is paid to the movement of the curved body with rotation about the roll and the identification of the presence of critical roll velocities. It is noted that for the case of passive movement there are three possible reasons for this interaction: aerodynamic, kinematic, inertial. A theoretical approach has been developed that takes into account the specific features of the geometry of deformed bodies. The approach made it possible in practical studies to determine the allowable deformation levels and its relationship with the motion parameters of deformed bodies. The stability analysis was carried out based on the stability criteria of the system solutions describing the body movement according to the Routh – Hurwitz criterion. The body parameters , which have a varying degree of influence on the stability of movement, are determined. In a more general case, the curve of the stability boundary for a given angular velocity in roll will have a more complex form than a simple hyperbola. The possibility of obtaining a direct solution to a nonlinear to the determining parameters equation is also shown. It will make it possible to obtain the dependences of the critical heel velocities and stability ranges on these parameters. Mathematical modeling based on the developed techniques, carried out for direct and curved bodies, showed that the body curvature has a significant effect on the displacement of the lines of derivative pitch moments in the angle of attack and the moment of sliding in the angle of slip relative to the limits of stability. The range of angular velocities for the roll is determined, in which a loss of stability is observed for the curved body. The effect of variations in the angular velocity and the relative change in the derivative of the yaw moment coefficient in the slip angle on the value of the determining factor from the stability conditions for the direct and curved bodies is analyzed. It is shown how the curvature of the body leads to a shift of the saddle point. The effect of a change in the Mach number on the determining coefficient of characteristic equations is analyzed.

scholarly journals Voltammetric Behaviour of Drug Molecules as a Predictor of Metabolic Liabilities

2020 ◽  
Vol 88 (4) ◽  
pp. 46 ◽  
Author(s):  
Hikari Fuchigami ◽  
Mandeep K. Bal ◽  
Dale A. C. Brownson ◽  
Craig E. Banks ◽  
Alan M. Jones
Keyword(s):  
Drug Stability ◽  
Pharmaceutical Research ◽  
Parent Drug ◽  
Vital Role ◽  
Oxidation Potential ◽  
The Body ◽  
Metabolic Stability ◽  
Drug Molecules ◽  
The Stability

Electron transfer plays a vital role in drug metabolism and underlying toxicity mechanisms. Currently, pharmaceutical research relies on pharmacokinetics (PK) and absorption, distribution, metabolism, elimination and toxicity (ADMET) measurements to understand and predict drug reactions in the body. Metabolic stability (and toxicity) prediction in the early phases of the drug discovery and development process is key in identifying a suitable lead compound for optimisation. Voltammetric methods have the potential to overcome the significant barrier of new drug failure rates, by giving insight into phase I metabolism events which can have a direct bearing on the stability and toxicity of the parent drug being dosed. Herein, we report for the first time a data-mining investigation into the voltammetric behaviour of reported drug molecules and their correlation with metabolic stability (indirectly measured via t½), as a potential predictor of drug stability/toxicity in vivo. We observed an inverse relationship between oxidation potential and drug stability. Furthermore, we selected and prepared short- (<10 min) and longer-circulation (>2 h) drug molecules to prospectively survey the relationship between oxidation potential and stability.

Sign in / Sign up

Export Citation Format

Share Document