2,319 results match your criteria cross-sectional geometry

Secondary Flows, Mixing, and Chemical Reaction Analysis of Droplet-Based Flow inside Serpentine Microchannels with Different Cross Sections.

Langmuir 2021 Apr 20. Epub 2021 Apr 20.

Department of Mechanical Engineering, Sharif University of Technology, >Tehran 165165161, Iran.

Chemical bioreactions are an important aspect of many recent microfluidic devices, and their applications in biomedical science have been growing worldwide. Droplet-based microreactors are among the attractive types of unit operations, which utilize droplets for enhancement in both mixing and chemical reactions. In the present study, a finite-volume-method (FVM) numerical investigation is conducted based on the volume-of-fluid (VOF) applying for the droplet-based flows. Read More

View Article and Full-Text PDF

Determinants of cardiac structure in frail and sarcopenic elderly adults.

Exp Gerontol 2021 Apr 14;150:111351. Epub 2021 Apr 14.

Department of Medicine and Surgery, University Medical School of Parma, Parma, Italy; University-Hospital of Parma, Parma, Italy; Geriatric Clinic Unit, University-Hospital of Parma, Parma, Italy.

Background: Cardiac structure and function change with age. The higher prevalence of left ventricular hypertrophy (LVH) with concentric remodeling is indicative of a typical geometric pattern of aging associated with a higher cardiovascular (CV) risk and diseases. The recent associations found between low left ventricular and skeletal mass in older patients with frailty and sarcopenia have raised great interest in investigating cardiac characteristics and determinants of left ventricular mass (LVM) in this population. Read More

View Article and Full-Text PDF

Bone mineral density and hip structure changes over one-year in collegiate distance runners and non-athlete controls.

Bone Rep 2021 Jun 23;14:101056. Epub 2021 Mar 23.

Human Performance Laboratory, Department of Health and Human Sciences, 1 LMU Drive, MS 8888, Los Angeles, CA 90045, USA.

Modification of bone is continuous throughout life and influenced by many factors, including physical activity. This study investigated changes in areal bone mineral density (aBMD) and hip structure among male and female collegiate distance runners and non-athlete controls over 12 months. Using dual-energy x-ray absorptiometry (DXA) and hip structure analysis (HSA) software, aBMD at the posterior-anterior (PA) and lateral spine, femoral neck, total hip (TH), whole body (WB), and bone geometry at the narrow neck (NN) of the femur was measured three times over 12 months. Read More

View Article and Full-Text PDF

Additively manufactured Ti-6Al-4V thin struts via laser powder bed fusion: Effect of building orientation on geometrical accuracy and mechanical properties.

J Mech Behav Biomed Mater 2021 Mar 27;119:104495. Epub 2021 Mar 27.

Department of Industrial Engineering - DII, University of Trento, Trento, Italy.

Porous metal lattice structures have a very high potential in biomedical applications, setting as innovative new generation prosthetic devices. Laser powder bed fusion (L-PBF) is one of the most widely used additive manufacturing (AM) techniques involved in the production of Ti6Al4V lattice structures. The mechanical and failure behavior of lattice structures is strongly affected by geometrical imperfections and defects occurring during L-PBF process. Read More

View Article and Full-Text PDF

Proximal Hip Geometry, Trabecular Bone Score, Bone Mineral Density and Bone Mineral Parameters in Patients With Cryptogenic and Hepatitis B Related Cirrhosis- A Study From the Indian Subcontinent.

J Clin Densitom 2021 Mar 4. Epub 2021 Mar 4.

Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Vellore, Tamil Nadu, India.

The impact of cryptogenic cirrhosis on skeleton has not been studied in Indian context. So this study investigated bone health in male patients with early cryptogenic cirrhosis as defined by Child-Turcot-Pugh A (CTP-A) categorization and compared it with patients diagnosed to have hepatitis B related chronic liver disease (CLD) on treatment and age, sex-matched healthy controls. It was a cross-sectional study, in which thirty male subjects were recruited in each group. Read More

View Article and Full-Text PDF

Effect of Tissue-Selective Estrogen Complex on Hip Structural Geometry in Postmenopausal Women: A 12-Month Study.

Front Endocrinol (Lausanne) 2021 11;12:649952. Epub 2021 Mar 11.

Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

Background: Hip structural analysis (HSA) is a method for evaluating bone geometry reflecting bone structural and biomechanical properties. However, tissue-selective estrogen complex (TSEC) treatment effects on HSA have not been investigated.

Objective: This study was performed to evaluate the effect of TSEC treatment on hip geometry in postmenopausal Korean women. Read More

View Article and Full-Text PDF

Insulin resistance surrogates and left ventricular hypertrophy in normotensive obese children.

Cardiol Young 2021 Mar 22:1-6. Epub 2021 Mar 22.

Clinic of Pediatrics, Clinical Center, Nis, Serbia, Medical Faculty, University of Nis, Nis, Serbia.

Background: The relationship between different surrogates of insulin resistance and left ventricular geometry in obese children is still unclear.

Objective: We sought to explore the relationship between commonly used measures of insulin sensitivity/resistance (homeostatic model assessment index, serum uric acid, and triglycerides to high-density lipoprotein cholesterol ratio) and left ventricular geometry in normotensive obese children.

Methods: In this cross-sectional study, 32 normotensive obese children were examined. Read More

View Article and Full-Text PDF

Compromised Volumetric Bone Density and Microarchitecture in men with Congenital Hypogonadotropic Hypogonadism.

J Clin Endocrinol Metab 2021 Mar 16. Epub 2021 Mar 16.

Department of Reproductive Endocrinology, Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Le Kremlin-Bicêtre, France.

Context: Men with Congenital Hypogonadotropic Hypogonadism (CHH) and Kallmann syndrome (KS) have both low circulating testosterone and estradiol levels. Whether bone structure is affected remains unknown.

Objective: To characterize bone geometry, volumetric density and microarchitecture in CHH/KS. Read More

View Article and Full-Text PDF

Role of the left coronary artery geometry configuration in atherosusceptibility: CFD simulations considering sPTT model for blood.

Comput Methods Biomech Biomed Engin 2021 Mar 4:1-16. Epub 2021 Mar 4.

Engineering Faculty, University of Porto, Porto, Portugal.

The achievement of clinically viable methodologies to simulate the hemodynamics in patient-specific coronary arteries is still a major challenge. Therefore, the novelty of this work is attained by the introduction of the viscoelastic property of blood in the numerical simulations, to study the role of the left coronary artery (LCA) geometry configuration in the atherosusceptibility. Apparently healthy patients were used and four different methodologies were tested. Read More

View Article and Full-Text PDF

Effect of receptors on the resonant and transient harmonic vibrations of Coronavirus.

J Mech Phys Solids 2021 May 18;150:104369. Epub 2021 Feb 18.

Department of Mechanical Engineering, MIT, United States.

The paper is concerned with the vibration characteristics of the Coronavirus family. There are some 25-100 receptors, commonly called spikes protruding from the envelope shell of the virus. Spikes, resembling the shape of a hot air balloon, may have a total mass similar to the mass of the lipid bi-layer shell. Read More

View Article and Full-Text PDF

Improving cell seeding efficiency through modification of fiber geometry in 3D printed scaffolds.

Biofabrication 2021 Feb 12. Epub 2021 Feb 12.

Regenerative Medicine Technologies Laboratory, Ente Ospedaliero Cantonale, Via Tesserete, 46, Lugano, 6900, SWITZERLAND.

Cell seeding on 3D scaffolds is a very delicate step in tissue engineering applications, influencing the outcome of the subsequent culture phase, and determining the results of the entire experiment. Thus, it is crucial to maximize its efficiency. To this purpose, a detailed study of the influence of the geometry of the scaffold fibers on dynamic seeding efficiency is presented. Read More

View Article and Full-Text PDF
February 2021

Small body size phenotypes among Middle and Later Stone Age Southern Africans.

J Hum Evol 2021 Mar 8;152:102943. Epub 2021 Feb 8.

Department of Archaeology, University of Cambridge, Cambridge, Cambridgeshire, CB2 3QG, UK; Department of Anthropology, University of Western Ontario, London, ON, N6A 5C2, UK; Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Str. 10, Jena, 07745, Germany.

Modern humans originated between 300 and 200 ka in structured populations throughout Africa, characterized by regional interaction and diversity. Acknowledgment of this complex Pleistocene population structure raises new questions about the emergence of phenotypic diversity. Holocene Southern African Later Stone Age (LSA) skeletons and descendant Khoe-San peoples have small adult body sizes that may reflect long-term adaptation to the Cape environment. Read More

View Article and Full-Text PDF

Bio-inspired evaporation from shaped interfaces: an experimental study.

Bioinspir Biomim 2021 Jan 19. Epub 2021 Jan 19.

Myers School of Art and Department of Biology, Biomimicry Research and Innovation Center, The University of Akron, Akron, OH 44325, USA.

Evaporative interfaces help process heat and substances in a variety of technical realms, from electronic to architectural applications. Because geometry affects the hydraulics, thermal properties and aerodynamics of evaporative devices, their performance can be tuned through design. While non-smooth interfaces are widely exploited to enhance transfer passively, surface area extension in packed volumes is a predominant line of research. Read More

View Article and Full-Text PDF
January 2021

Do proximal hip geometry, trabecular microarchitecture, and prevalent vertebral fractures differ in postmenopausal women with type 2 diabetes mellitus? A cross-sectional study from a teaching hospital in southern India.

Osteoporos Int 2021 Jan 27. Epub 2021 Jan 27.

Department of Endocrinology, Christian Medical College, Vellore, India.

This study from southern India showed that the trabecular microarchitecture and proximal hip geometry were significantly impaired in postmenopausal women with diabetes as compared to age and BMI matched non-diabetic controls. This is despite there being no significant difference in bone mineral density at the femoral neck and hip not between both groups. One-third of the study subjects with type 2 diabetes had prevalent vertebral fractures. Read More

View Article and Full-Text PDF
January 2021

Population-based, three-dimensional analysis of age- and sex-related femur shaft geometry differences.

Osteoporos Int 2021 Jan 26. Epub 2021 Jan 26.

Department of Orthopaedics, Asan Medical Center, Seoul, Republic of Korea.

This study deals with differences of femoral geometric focus on the bowing and width. Analysis using three-dimensional skeletonization showed increase of femoral bowing and femur width over life (more in women), and widening of the medullary canal only in women after 50 years old, not in men.

Introduction: The changes in femur geometry that occur with aging and lead to fragility or insufficiency fracture remain unclear. Read More

View Article and Full-Text PDF
January 2021

Upright Magnetic Resonance Imaging Study of Cervical Flexor/Extensor Musculature and Cervical Lordosis in Females After Helmet Wear.

Mil Med 2021 01;186(Suppl 1):632-638

Center for NeuroTrauma Research, Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA.

Introduction: Addition of head-supported mass imparts greater demand on the human neck to maintain functionality. The same head-supported mass induces greater demand on the female spine than the male spine because female necks are comparatively slender. Prevalence of neck pain is greater in military than civilian population because of the head-borne mass (among other factors). Read More

View Article and Full-Text PDF
January 2021

Left ventricular and atrial global strain evaluation within subtypes of ventricular remodeling.

Echocardiography 2021 Feb 23;38(2):280-288. Epub 2021 Jan 23.

Department of Nuclear Cardiology, National Institute of Cardiology Ignacio Chavez, Mexico City, Mexico.

Background: Left ventricular hypertrophy is associated with poor prognosis and adverse events. Left ventricular and left atrial global strain and left atrial reservoir strain (LV-GS; LA-GS; LA-RS) could be used as markers for myocardial function in different ventricular remodeling forms. This study aimed to evaluate LV-GS and LA-GS scores in different ventricular remodeling variants and identify risk factors for myocardial dysfunction. Read More

View Article and Full-Text PDF
February 2021

Oral Estradiol Impact on Mitigating Unloading-Induced Bone Loss in Ovary-Intact Rats.

Aerosp Med Hum Perform 2021 Feb;92(2):65-74

The impact of the spaceflight environment on endogenous estrogen production in female crewmembers and the resulting impact on other adaptations, like bone loss, is an under-investigated topic. Hence, we investigated the interaction of exogenous 17- estradiol (E2) treatment and disuse to test the hypothesis that E2 treatment would mitigate disuse-induced bone loss. There were 40 virgin female Sprague-Dawley rats (5 mo old) randomized to placebo (PL; 0 ppm E2) or estrogen (E2; 10 ppm E2) treatments, delivered via custom-made rodent diets; half of each group was randomized to either weightbearing (WB) or hindlimb unloading (HU) for 39 d. Read More

View Article and Full-Text PDF
February 2021

Age-related site-specific modifications in diaphyseal structural properties of the human fibula: Furrows and cross-sectional geometry.

Am J Phys Anthropol 2020 11 16;173(3):535-555. Epub 2020 Aug 16.

UMR 7194 Histoire Naturelle de l'Homme Préhistorique, CNRS, Muséum National d'Histoire Naturelle, Université Perpignan Via Domitia, Centre de Recherche Préhistorique de Tautavel, Tautavel, France.

Objectives: Fibular structure is related to locomotor behavior, which allows an exploration of mobility in past human populations with diaphyseal cross-sectional geometry (CSG). However, bone structure depends on age-related changes. Nonmechanical alterations can affect biomechanical investigations. Read More

View Article and Full-Text PDF
November 2020

Microfluidic on-chip production of microgels using combined geometries.

Sci Rep 2021 Jan 15;11(1):1565. Epub 2021 Jan 15.

Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran.

Microfluidic on-chip production of microgels using external gelation can serve numerous applications that involve encapsulation of sensitive cargos. Nevertheless, on-chip production of microgels in microfluidic devices can be challenging due to problems induced by the rapid increase in precursor solution viscosity like clogging. Here, a novel design incorporating a step, which includes a sudden increase in cross-sectional area, before a flow-focusing nozzle was proposed for microfluidic droplet generators. Read More

View Article and Full-Text PDF
January 2021

Changes in aortic arch geometry and the risk for Stanford B dissection.

J Thorac Dis 2020 Dec;12(12):7193-7201

Department of Vascular Surgery, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Background: The increase in aortic diameter is not closely associated with type B aortic dissection (TBAD); morphological risk factors other than aortic diameter may help to better identify patients at risk for TBAD. The purpose of this study was to investigate possible morphological factors associated with the occurrence of TBAD.

Methods: This study was a retrospective, multicenter, cross-sectional study. Read More

View Article and Full-Text PDF
December 2020

A R-Script for Generating Multiple Sclerosis Lesion Pattern Discrimination Plots.

Brain Sci 2021 Jan 12;11(1). Epub 2021 Jan 12.

Department of Neurology, Christian Doppler Medical Center, Paracelsus Medical University, Ignaz-Harrer Str. 79, 5020 Salzburg, Austria.

One significant characteristic of Multiple Sclerosis (MS), a chronic inflammatory demyelinating disease of the central nervous system, is the evolution of highly variable patterns of white matter lesions. Based on geostatistical metrics, the MS-Lesion Pattern Discrimination Plot reduces complex three- and four-dimensional configurations of MS-White Matter Lesions to a well-arranged and standardized two-dimensional plot that facilitates follow-up, cross-sectional and medication impact analysis. Here, we present a script that generates the MS-Lesion Pattern Discrimination Plot, using the widespread statistical computing environment R. Read More

View Article and Full-Text PDF
January 2021

Ontogenetic and morphological variation in primate long bones reflects signals of size and behavior.

Am J Phys Anthropol 2021 02 24;174(2):327-351. Epub 2020 Dec 24.

Department of Anthropology, Durham University, Durham, United Kingdom.

Objectives: Many primates change their locomotor behavior as they mature from infancy to adulthood. Here we investigate how long bone cross-sectional geometry in Pan, Gorilla, Pongo, Hylobatidae, and Macaca varies in shape and form over ontogeny, including whether specific diaphyseal cross sections exhibit signals of periosteal adaptation or canalization.

Materials And Methods: Diaphyseal cross sections were analyzed in an ontogenetic series across infant, juvenile, and adult subgroups. Read More

View Article and Full-Text PDF
February 2021

Gastrocnemius Medialis Muscle Geometry and Extensibility in Typically Developing Children and Children With Spastic Paresis Aged 6-13 Years.

Front Physiol 2020 23;11:528522. Epub 2020 Nov 23.

Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.

Gait of children with spastic paresis (SP) is frequently characterized by a reduced ankle range of motion, presumably due to reduced extensibility of the triceps surae (TS) muscle. Little is known about how morphological muscle characteristics in SP children are affected. The aim of this study was to compare gastrocnemius medialis (GM) muscle geometry and extensibility in children with SP with those of typically developing (TD) children and assess how GM morphology is related to its extensibility. Read More

View Article and Full-Text PDF
November 2020

Electron energy-loss spectroscopy of surface plasmon activity in wrinkled gold structures.

J Chem Phys 2020 Dec;153(22):224703

Department of Materials Science and Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada.

The surface plasmon response of a cross-sectional segment of a wrinkled gold film is studied using electron energy loss spectroscopy (EELS). EELS data demonstrate that wrinkled gold structures act as a suitable substrate for surface plasmons to propagate. The intense surface variations in these structures facilitate the resonance of a wide range of surface plasmons, leading to the broadband surface plasmon response of these geometries from the near-infrared to visible wavelengths. Read More

View Article and Full-Text PDF
December 2020

Peak Flow in Model Aorta Through Bi-Leaflet Mechanical Heart Valve with Varying Orientation.

ASAIO J 2020 Dec 10. Epub 2020 Dec 10.

From the Department of Aerospace Engineering, Indian Institute of Technology Bombay, Mumbai, India.

This study aims to numerically investigate the effect of bi-leaflet mechanical heart valve (BMHV) orientation on flow pattern in a realistic human aorta model with branches. The aorta model geometry is based on anatomical shape and dimensions involving aortic arch with twist and branches. Unsteady numerical simulations have been carried out to investigate the peak systolic flow in aorta through a BMHV installed at three different orientations, marked as 0°, 45°, and 90°. Read More

View Article and Full-Text PDF
December 2020

Evolution of Thin-Liquid Films Surrounding Bubbles in Microfluidics and Their Impact on the Pressure Drop and Fluid Movement.

Langmuir 2020 Dec 6;36(49):15102-15111. Epub 2020 Dec 6.

School of Engineering, The University of Edinburgh, The King's Buildings, Robert Stevenson Road, Edinburgh EH9 3JL, U.K.

The evolution of thin-liquid films in a microchannel is one of the most critical and intricate phenomena to understand two-phase movement, evaporation, micromixing, heat transfer, chemical synthesis, biological processes, and efficient energy devices. In this paper, we demonstrate experimentally the effect of a liquid film on the removal of an initially dry and lodged bubble in laser-etched poly(methyl methacrylate) microfluidic networks and discuss the evolution of the liquid film in accordance with the bubble superficial velocity and the effect of liquid properties and branch angle on the evolution of the liquid film and the pressure drop. During the removal of a dry bubble, four stages have been observed in the bubble velocity profile and they directly relate to the evolution of the liquid film. Read More

View Article and Full-Text PDF
December 2020

Vertical pullout tests of orchard trees for bio-inspired engineering of anchorage and foundation systems.

Bioinspir Biomim 2020 11 28;16(1):016009. Epub 2020 Nov 28.

Department of Civil and Environmental Engineering, University of California Davis, 1 Shields Avenue, Davis, 95616, California, United States of America.

Application of bio-inspired design in geotechnical engineering shows promise for improving the energy and material efficiency of several processes in infrastructure construction and site characterization. This project examines tree root systems for use in future bio-inspired design to improve the capacity of foundations used to support, for example, buildings and bridges. Foundation and anchorage elements used in industry are comprised almost solely of linear elements with a constant cross-sectional geometry. Read More

View Article and Full-Text PDF
November 2020

Feature-based automated segmentation of ablation zones by fuzzy c-mean clustering during low-dose computed tomography.

Med Phys 2021 Feb 18;48(2):703-714. Epub 2020 Dec 18.

Department of Biomedical Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI, 53706, USA.

Purpose: Intra-procedural monitoring and post-procedural follow-up is necessary for a successful ablation treatment. An imaging technique which can assess the ablation geometry accurately is beneficial to monitor and evaluate treatment. In this study, we developed an automated ablation segmentation technique for serial low-dose, noisy ablation computed tomography (CT) or contrast-enhanced CT (CECT). Read More

View Article and Full-Text PDF
February 2021

Abnormal diurnal blood pressure profile and hypertension-mediated organ damage in nondiabetic chronic kidney disease G1-G3b patients.

Blood Press Monit 2021 Feb;26(1):22-29

Department of Nephrology, Hypertension and Internal Medicine.

Objective: Chronic kidney disease (CKD) is associated with high cardiovascular risk. Prevalence of hypertension and hypertension-mediated organ damage (HMOD) increases with CKD progression. Nocturnal blood pressure (BP) is a strong predictor of cardiovascular complications. Read More

View Article and Full-Text PDF
February 2021