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https://www.readbyqxmd.com/read/28453556/characterization-of-interfragmentary-motion-associated-with-common-osteosynthesis-devices-for-rat-fracture-healing-studies
#1
Nicholaus Meyers, Matthias Sukopp, Rudolf Jäger, Malte Steiner, Romano Matthys, Bernd Lapatki, Anita Ignatius, Lutz Claes
Rat models are widely used in preclinical studies investigating fracture healing. The interfragmentary movement at a fracture site is critical to the course of healing and therefore demands definition in order to aptly interpret the experimental results. Estimation of this movement requires knowledge of the fixation stiffness and loading. The characteristic loading for the rat femur has been estimated, but the stiffness of fixation used in rat studies has yet to be fully described. This study aimed to determine the 6 degree of freedom stiffness of four commonly used implants, two external fixators (RatExFix and UlmExFix), a locking plate, and a locking intramedullary nail, in all degrees of freedom and estimate the interfragmentary movement under specific physiological loads...
2017: PloS One
https://www.readbyqxmd.com/read/28449548/vibration-induced-property-change-in-the-melting-and-solidifying-process-of-metallic-nanoparticles
#2
Yonggang Zheng, Liquan Ding, Hongfei Ye, Zhen Chen
Tuning material properties in the 3-D printing process of metallic parts is a challenging task of current interests. Much research has been conducted to understand the effects of controlling parameters such as the particle geometry (size and shape), heating, and cooling ways on the outcome of the printing process. However, nothing has been done to explore the system vibration effect. This letter reports our findings on the vibration-induced property change in the melting and solidifying process of silver nanoparticles with the use of molecular dynamics simulation...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28449514/left-ventricular-outflow-tract-obstruction-due-to-a-left-ventricular-myxoma-that-was-misidentified-as-an-accessory-mitral-valve-tissue
#3
Seung-Hoon Baek, Hee Young Kim, Hyae Jin Kim, Sang Wook Shin, Hye Jin Kim, Yun Mi Choi, Eun Ji Choi, Eunjung Chang, Hong-Sik Son
We report obstruction of the left ventricle outflow tract (LVOT) caused by cardiac myxoma that was misidentified as an accessory mitral valve tissue preoperatively. A 65-year-old woman presented with chest discomfort that persisted for 7 days. Transthoracic echocardiography (TTE) revealed a mobile, low-echogenic, balloon-shaped mass attached to the anterior mitral valve leaflet and papillary muscle, which was suspected to be an accessory mitral valve tissue. Because the mass caused LVOT obstruction and it could result in hemodynamic instability, emergency operation was performed...
March 2017: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28448922/affine-and-non-affine-deformations-quantified-in-cytoskeletal-networks-through-three-dimensional-form-finding-model
#4
Yifan Wang, Jinghai Gong, Denis Wirtz, Benjamin W Schafer
Actin filaments and cross-linkers are main components of cytoskeletal networks in eukaryotic cells, and they support bending moments and axial forces respectively. A three-dimensional form-finding model is proposed in this work to investigate affine and non-affine deformations in cytoskeletal networks. In recent studies, modeling of cytoskeletal networks turns out to be a key piece in the cell mechanics puzzle. We used form-finding analysis to compute and analyze cytoskeletal models. A three-dimensional model is much more flexible and contains more elements than a two-dimensional model, and non-linear finite element analysis is difficult to converge...
April 20, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28448919/mechanochemical-mechanism-of-integrin-clustering-modulated-by-nanoscale-ligand-spacing-and-rigidity-of-extracellular-substrates
#5
Jing Yu, Jianyong Huang, John A Jansen, Chunyang Xiong, X Frank Walboomers
Experimental findings indicate that cell function and behavior such as cell growth, division, migration and differentiation, are subtly regulated via integrin-dependent cell adhesion. Cell adhesion is influenced by nanoscale ligand spacing and rigidity of extracellular substrates, as cell adhesion drops greatly when the ligand spacing is larger than ~60nm, and cell adhesion is stronger on stiff than soft substrates. However, how nanoscale ligand spacing and substrate stiffness jointly affect integrin clustering and hence nascent cell adhesion remains to be elucidated...
April 14, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28448191/total-arterial-compliance-estimated-by-a-novel-method-is-better-related-to-left-ventricular-mass-compared-to-aortic-pulse-wave-velocity-the-safar-study
#6
Theodore G Papaioannou, Athanase D Protogerou, Antonis Argyris, Evangelia Aissopou, George Georgiopoulos, Efthimia Nasothimiou, Christos Tountas, Petros P Sfikakis, Nikolaos Stergiopulos, Dimitrios Tousoulis
The investigation of the association between total arterial compliance (CT)-estimated by a novel technique-with left ventricular mass (LVM) and hypertrophy (LVH). Our hypothesis was that CT may be better related to LVM compared to the gold-standard regional aortic stiffness. Within the frame of the ongoing cross-sectional study "SAFAR," 226 subjects with established hypertension or with suspected hypertension underwent blood pressure (BP) assessment, carotid-to-femoral pulse wave velocity (cf-PWV), and echocardiographic measurement of LVM...
2017: Clinical and Experimental Hypertension: CHE
https://www.readbyqxmd.com/read/28448179/comparison-of-arterial-stiffness-in-preeclamptic-and-normotensive-pregnant-women-from-a-semi-rural-region-of-south-africa
#7
A Namugowa, J Iputo, J Wandabwa, A Meeme, G A B Buga
BACKGROUND: Preeclampsia is associated with arterial stiffness and endothelial dysfunction. The pathophysiology of arterial tone in preeclampsia has not been well described in rural African population, where the incidence is higher. OBJECTIVE: The aim of the study was to compare arterial tone of preeclamptic with pregnant normotensive women assessed with noninvasive techniques, using applanation tonometry with SphygmoCor. METHOD: This was a cross-sectional study...
2017: Clinical and Experimental Hypertension: CHE
https://www.readbyqxmd.com/read/28447127/bone-adaptation-of-a-biologically-reconstructed-femur-after-ewing-sarcoma-long-term-morphological-and-densitometric-evolution
#8
Giordano Valente, Fulvia Taddei, Andrea Roncari, Enrico Schileo, Marco Manfrini
Combining bone allografts and vascularized fibular autografts in intercalary reconstructions after resection of bone sarcomas is of particular interest in young patients as it facilitates bone healing and union and helps reduce fractures. However, adverse events related to bone adaptation still occur. Bone adaptation is driven by mechanical loading, but no quantitative biomechanical studies exist that would help surgical planning and rehabilitation. We analyzed the bone adaptation of a successful femoral reconstruction after Ewing sarcoma during 76-month follow-up using a novel methodology that allows CT-based quantification of morphology and density...
April 26, 2017: Skeletal Radiology
https://www.readbyqxmd.com/read/28446647/relationship-between-carotid-arterial-properties-and-cerebral-white-matter-hyperintensities
#9
Tatjana Rundek, David Della-Morte, Hannah Gardener, Chuanhui Dong, Matthew S Markert, Jose Gutierrez, Eugene Roberts, Mitchell S V Elkind, Charles DeCarli, Ralph L Sacco, Clinton B Wright
OBJECTIVE: Since arterial stiffness is a functional measure of arterial compliance and may be an important marker of cerebrovascular disease, we examined the association of carotid artery stiffness with white matter hyperintensity volume (WMHV) in a cross-sectional study of 1,166 stroke-free participants. METHODS: Carotid beta stiffness index (STIFF) was assessed by M-mode ultrasound of the common carotid artery and calculated as the ratio of natural log of the difference between systolic and diastolic blood pressure over STRAIN, a ratio of the difference between carotid systolic and diastolic diameter (DD) divided by DD...
April 26, 2017: Neurology
https://www.readbyqxmd.com/read/28446031/influences-of-geometrical-and-mechanical-properties-of-bone-tissues-in-mandible-behaviour-experimental-and-numerical-predictions
#10
A Ramos, Yi Nyashin, M Mesnard
The properties and geometry of bone in the mandible play a key role in mandible behaviour during a person's lifetime, and attention needs to be paid to the influence of bone properties. We analysed the effect of bone geometry, size and bone properties in mandible behaviour, experimenting on cadaveric mandibles and FE models. The study was developed using the geometry of a cadaveric mandible without teeth. Three models of cadaveric condyles were experimentally tested with instrumented with four rosettes, and a condyle reaction of 300 N...
April 26, 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/28445817/nanostructural-and-mechanical-property-changes-to-spider-silk-as-a-consequence-of-insecticide-exposure
#11
Marco Benamú, Mariángeles Lacava, Luis F García, Martín Santana, Jian Fang, Xungai Wang, Sean J Blamires
Neonicotinoids are one of the world's most extensively used insecticides, but their sub-lethal influences on non-target and beneficial organisms are not well known. Here we exposed the orb web spider Parawixia audax, which is found on arable lands in Uruguay, to a sub-lethal concentration of the broad spectrum insecticide Geonex (thiamethoxam + lambda-cyhalothrin) and monitored their web building. We collected their major ampullate silk and subjected it to tensile tests, wide-angle X-ray diffraction (WAXS) analysis, and amino acid composition analysis...
April 21, 2017: Chemosphere
https://www.readbyqxmd.com/read/28445756/membrane-mechanics-of-primary-afferent-neurons-in-the-dorsal-root-ganglia-of-rats
#12
Hirosato Kanda, Jianguo G Gu
Membrane mechanics is an important biological factor regulating many cellular functions including cell motility, intercellular and intracellular signaling, gene expression, and membrane ion channel activity. Primary afferent neurons transduce sensory information about temperature, touch, and pain. These sensory functions may be profoundly affected by the states of primary afferent neuron mechanics. However, membrane mechanics of primary afferent neurons is largely unknown. In this study, we established the optical trapping technique for determining membrane mechanics of cultured primary afferent neurons of the dorsal root ganglia (DRG)...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445745/increased-tissue-stiffness-in-tumors-from-mice-with-neurofibromatosis-1-optic-glioma
#13
Christopher Walter, Lindsey Crawford, Melinda Lai, Joseph A Toonen, Yuan Pan, Shelly Sakiyama-Elbert, David H Gutmann, Amit Pathak
Children with neurofibromatosis type 1 (NF1) cancer predisposition syndrome are prone to the development of low-grade brain tumors (gliomas) within the optic pathway (optic gliomas). One of the key obstacles to developing successful therapeutic strategies for these tumors is the striking lack of information about the mechanical properties that characterize these tumors relative to non-neoplastic optic nerve tissue. To study the physical changes that may occur when an optic nerve glioma is present, we employed atomic force microscopy to measure the stiffness of healthy versus tumor-bearing optic nerve tissue...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445258/renal-vascular-calcification-and-response-to-renal-nerve-denervation-in-resistant-hypertension
#14
Annemiek F Hoogerwaard, Mark R de Jong, Ahmet Adiyaman, Jaap Jan J Smit, Peter P H M Delnoy, Jan-Evert Heeg, Boudewijn A A M van Hasselt, Anand R Ramdat Misier, Arif Elvan
Renal sympathetic nerve denervation (RDN) is accepted as a treatment option for patients with resistant hypertension. However, results on decline in ambulatory blood pressure (BP) measurement (ABPM) are conflicting. The high rate of nonresponders may be related to increased systemic vascular stiffness rather than sympathetic overdrive. A single center, prospective registry including 26 patients with treatment resistant hypertension who underwent RDN at the Isala Hospital in the Netherlands. Renal perivascular calcium scores were obtained from noncontrast computed tomography scans...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28445206/independent-effects-of-blood-pressure-and-parathyroid-hormone-on-aortic-pulse-wave-velocity-in-untreated-chinese-patients
#15
Yi-Bang Cheng, Li-Hua Li, Qian-Hui Guo, Fei-Ka Li, Qi-Fang Huang, Chang-Sheng Sheng, Ji-Guang Wang, Jan A Staessen, Yan Li
OBJECTIVE: Whether or not calcium-regulating hormones stiffen arteries independent of blood pressure (BP) is uncertain. We investigated the independent associations of carotid-femoral pulse wave velocity (PWV) with 25-hydroxy-vitamin D [25(OH)D], parathyroid hormone (PTH) and 24-h ambulatory BP in untreated Chinese patients. METHODS: Consecutive untreated patients referred for ambulatory BP monitoring were recruited. PWV was measured with a high-fidelity micromanometer and the SphygmoCor software (AtCor Medical, West Ryde, New South Wales, Australia)...
April 25, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28444935/hydration-status-influences-the-measurement-of-arterial-stiffness
#16
Aaron R Caldwell, Matthew A Tucker, Jenna Burchfield, Nicole E Moyen, Alf Z Satterfield, Ashley Six, Brendon P McDermott, Sean W Mulvenon, Matthew S Ganio
Consensus guidelines have attempted to standardize the measurement and interpretation of pulse wave velocity (PWV); however, guidelines have not addressed whether hydration status affects PWV. Moreover, multiple studies have utilized heat stress to reduce arterial stiffness which may lead to dehydration. This study utilized two experiments to investigate the effects of dehydration on PWV at rest and during passive heat stress. In experiment 1, subjects (n = 19) completed two trials, one in which they arrived euhydrated and one dehydrated (1·2[1·0]% body mass loss)...
April 26, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28444436/acute-effects-of-static-stretching-on-muscle-tendon-mechanics-of-quadriceps-and-plantar-flexor-muscles
#17
Tom Bouvier, Jules Opplert, Carole Cometti, Nicolas Babault
PURPOSE: This study aimed to determine the acute effects of static stretching on stiffness indexes of two muscle groups with a contrasting difference in muscle-tendon proportion. METHODS: Eleven active males were tested on an isokinetic dynamometer during four sessions randomly presented. Two sessions were dedicated to quadriceps and the two others to triceps surae muscles. Before and immediately after the stretching procedure (5 × 30 s), gastrocnemius medialis and rectus femoris fascicle length and myotendinous junction elongation were determined using ultrasonography...
April 25, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28444097/chronic-polyarthritis-as-the-first-manifestation-of-childhood-systemic-polyarteritis-nodosa
#18
Glaucia Vanessa Novak, Koken Hayashi, Kohei Sampa, Yosuke Okumura, Gabriela Ribeiro Viola Ferreira, Clovis Artur Silva
Arthritis has been reported as an acute pattern, generally evanescent with oligoarthritis, mostly affecting knees and ankles in childhood systemic polyarteritis nodosa. However, chronic polyarthritis with morning stiffness mimicking juvenile idiopathic arthritis has not been reported. We describe the case of a 4-year old girl who had additive and chronic polyarthritis with edema, tenderness, pain on motion and morning stiffness for 2 months. After 45 days, she also presented painful subcutaneous nodules and erythematous-violaceous lesions in the extensor region of upper and lower limbs...
January 2017: Einstein
https://www.readbyqxmd.com/read/28442120/american-gastroenterological-association-institute-technical-review-on-the-role-of-elastography-in-chronic-liver-diseases
#19
Siddharth Singh, Andrew J Muir, Douglas T Dieterich, Yngve T Falck-Ytter
Chronic liver diseases (CLDs), due to chronic hepatitis C; hepatitis B; nonalcoholic fatty liver diseases (NAFLD); and alcoholic liver disease, are a leading cause of morbidity and mortality globally. Early identification of patients with cirrhosis at high risk of progression to liver-related complications may facilitate timely care and improve outcomes. With risks and misclassification associated with invasive tests, such as liver biopsy, noninvasive imaging modalities for liver fibrosis assessment have gained popularity...
May 2017: Gastroenterology
https://www.readbyqxmd.com/read/28442094/elderly-male-with-neck-stiffness-and-fever
#20
Taichi Imamura, Seth Lotterman, Catherine Glazer
No abstract text is available yet for this article.
May 2017: Annals of Emergency Medicine
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