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  Subjects -> BIOLOGY (Total: 2982 journals)
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BIOLOGY (1420 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1720 Journals sorted alphabetically
AAPS Journal     Hybrid Journal   (Followers: 18)
Achievements in the Life Sciences     Open Access   (Followers: 4)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 20)
Acta Biologica Colombiana     Open Access   (Followers: 6)
Acta Biologica Hungarica     Full-text available via subscription   (Followers: 4)
Acta Biologica Sibirica     Open Access  
Acta Biomaterialia     Hybrid Journal   (Followers: 25)
Acta Biotheoretica     Hybrid Journal   (Followers: 5)
Acta Chiropterologica     Full-text available via subscription   (Followers: 6)
acta ethologica     Hybrid Journal   (Followers: 4)
Acta Limnologica Brasiliensia     Open Access   (Followers: 3)
Acta Médica Costarricense     Open Access   (Followers: 2)
Acta Musei Silesiae, Scientiae Naturales : The Journal of Silesian Museum in Opava     Open Access  
Acta Parasitologica     Hybrid Journal   (Followers: 9)
Acta Scientiarum. Biological Sciences     Open Access   (Followers: 2)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
Actualidades Biológicas     Open Access   (Followers: 1)
Advanced Health Care Technologies     Open Access   (Followers: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Bioinformatics     Open Access   (Followers: 18)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4)
Advances in Biology     Open Access   (Followers: 8)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Advances in Cell Biology     Open Access   (Followers: 23)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Ecological Research     Full-text available via subscription   (Followers: 39)
Advances in Ecology     Open Access   (Followers: 13)
Advances in Environmental Sciences - International Journal of the Bioflux Society     Open Access   (Followers: 20)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Genome Biology     Full-text available via subscription   (Followers: 12)
Advances in High Energy Physics     Open Access   (Followers: 20)
Advances in Human Biology     Open Access  
Advances in Life Science and Technology     Open Access   (Followers: 14)
Advances in Life Sciences     Open Access   (Followers: 4)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3)
Advances in Regenerative Biology     Open Access   (Followers: 1)
Advances in Structural Biology     Full-text available via subscription   (Followers: 7)
Advances in Virus Research     Full-text available via subscription   (Followers: 5)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 6)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 1)
Ageing Research Reviews     Hybrid Journal   (Followers: 7)
Aging Cell     Open Access   (Followers: 9)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agrokreatif Jurnal Ilmiah Pengabdian kepada Masyarakat     Open Access  
AJP Cell Physiology     Full-text available via subscription   (Followers: 13)
AJP Endocrinology and Metabolism     Full-text available via subscription   (Followers: 22)
AJP Lung Cellular and Molecular Physiology     Full-text available via subscription   (Followers: 3)
Al-Kauniyah : Jurnal Biologi     Open Access  
Alasbimn Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Biology Teacher     Full-text available via subscription   (Followers: 12)
American Fern Journal     Full-text available via subscription   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 10)
American Journal of Bioethics     Hybrid Journal   (Followers: 10)
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Human Biology     Hybrid Journal   (Followers: 12)
American Journal of Medical and Biological Research     Open Access   (Followers: 5)
American Journal of Plant Sciences     Open Access   (Followers: 19)
American Journal of Primatology     Hybrid Journal   (Followers: 14)
American Malacological Bulletin     Full-text available via subscription   (Followers: 3)
American Naturalist     Full-text available via subscription   (Followers: 63)
Amphibia-Reptilia     Hybrid Journal   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4)
Analytical Methods     Full-text available via subscription   (Followers: 7)
Anatomical Science International     Hybrid Journal   (Followers: 2)
Animal Cells and Systems     Hybrid Journal   (Followers: 4)
Annales de Limnologie - International Journal of Limnology     Hybrid Journal   (Followers: 1)
Annales françaises d'Oto-rhino-laryngologie et de Pathologie Cervico-faciale     Full-text available via subscription   (Followers: 3)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3)
Annales UMCS, Biologia     Open Access   (Followers: 1)
Annals of Applied Biology     Hybrid Journal   (Followers: 8)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18)
Annals of Human Biology     Hybrid Journal   (Followers: 4)
Annual Review of Biomedical Engineering     Full-text available via subscription   (Followers: 17)
Annual Review of Biophysics     Full-text available via subscription   (Followers: 25)
Annual Review of Cell and Developmental Biology     Full-text available via subscription   (Followers: 37)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Annual Review of Genomics and Human Genetics     Full-text available via subscription   (Followers: 18)
Annual Review of Phytopathology     Full-text available via subscription   (Followers: 10)
Anthropological Review     Open Access   (Followers: 23)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antibiotics     Open Access   (Followers: 8)
Antioxidants     Open Access   (Followers: 4)
Antioxidants & Redox Signaling     Hybrid Journal   (Followers: 8)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apidologie     Hybrid Journal   (Followers: 4)
Apmis     Hybrid Journal   (Followers: 1)
APOPTOSIS     Hybrid Journal   (Followers: 8)
Applied Bionics and Biomechanics     Open Access   (Followers: 8)
Applied Vegetation Science     Full-text available via subscription   (Followers: 9)
Aquaculture Environment Interactions     Open Access   (Followers: 2)
Aquaculture International     Hybrid Journal   (Followers: 22)
Aquaculture Reports     Open Access   (Followers: 3)
Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society     Open Access   (Followers: 6)
Aquatic Biology     Open Access   (Followers: 4)
Aquatic Ecology     Hybrid Journal   (Followers: 30)
Aquatic Ecosystem Health & Management     Hybrid Journal   (Followers: 13)
Aquatic Science and Technology     Open Access   (Followers: 3)
Aquatic Toxicology     Hybrid Journal   (Followers: 19)
Archaea     Open Access   (Followers: 3)
Archiv für Molluskenkunde: International Journal of Malacology     Full-text available via subscription   (Followers: 3)
Archives of Biomedical Sciences     Open Access   (Followers: 7)
Archives of Microbiology     Hybrid Journal   (Followers: 8)
Archives of Natural History     Hybrid Journal   (Followers: 7)
Archives of Oral Biology     Hybrid Journal   (Followers: 2)
Archives of Virology     Hybrid Journal   (Followers: 5)
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arquivos do Museu Dinâmico Interdisciplinar     Open Access  
Arthropod Structure & Development     Hybrid Journal   (Followers: 2)
Arthropods     Open Access   (Followers: 1)
Artificial DNA: PNA & XNA     Hybrid Journal   (Followers: 2)
Artificial Photosynthesis     Open Access   (Followers: 1)
Asian Bioethics Review     Full-text available via subscription   (Followers: 1)
Asian Journal of Biodiversity     Open Access   (Followers: 5)
Asian Journal of Biological Sciences     Open Access   (Followers: 3)
Asian Journal of Cell Biology     Open Access   (Followers: 5)
Asian Journal of Developmental Biology     Open Access   (Followers: 2)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 2)
Asian Journal of Nematology     Open Access   (Followers: 3)
Asian Journal of Poultry Science     Open Access   (Followers: 4)
Australian Life Scientist     Full-text available via subscription   (Followers: 2)
Australian Mammalogy     Hybrid Journal   (Followers: 5)
Autophagy     Hybrid Journal   (Followers: 2)
Avian Biology Research     Full-text available via subscription   (Followers: 3)
Avian Conservation and Ecology     Open Access   (Followers: 7)
Bacteriology Journal     Open Access   (Followers: 2)
Bacteriophage     Full-text available via subscription   (Followers: 3)
Bangladesh Journal of Bioethics     Open Access  
Bangladesh Journal of Plant Taxonomy     Open Access  
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Berita Biologi     Open Access   (Followers: 1)
Between the Species     Open Access   (Followers: 1)
Bio Tribune Magazine     Hybrid Journal  
BIO Web of Conferences     Open Access  
BIO-Complexity     Open Access  
Bio-Grafía. Escritos sobre la Biología y su enseñanza     Open Access  
Bioanalytical Reviews     Hybrid Journal   (Followers: 2)
Biocatalysis and Biotransformation     Hybrid Journal   (Followers: 6)
Biochemistry and Cell Biology     Full-text available via subscription   (Followers: 14)
Biochimie     Hybrid Journal   (Followers: 7)
BioControl     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodemography and Social Biology     Hybrid Journal   (Followers: 1)
Biodiversidad Colombia     Open Access  
Biodiversity : Research and Conservation     Open Access   (Followers: 26)
Biodiversity and Natural History     Open Access   (Followers: 5)
Biodiversity Data Journal     Open Access   (Followers: 3)
Biodiversity Informatics     Open Access  
Bioedukasi : Jurnal Pendidikan Biologi FKIP UM Metro     Open Access  
Bioeksperimen : Jurnal Penelitian Biologi     Open Access  
Bioelectrochemistry     Hybrid Journal   (Followers: 2)
Bioelectromagnetics     Hybrid Journal   (Followers: 1)
Bioenergy Research     Hybrid Journal   (Followers: 2)
Bioengineering and Bioscience     Open Access   (Followers: 1)
BioEssays     Hybrid Journal   (Followers: 10)
Bioethics     Hybrid Journal   (Followers: 14)
BioéthiqueOnline     Open Access  
Biofabrication     Hybrid Journal   (Followers: 3)
Biogeosciences (BG)     Open Access   (Followers: 9)
Biogeosciences Discussions (BGD)     Open Access   (Followers: 1)
Bioinformatics     Hybrid Journal   (Followers: 230)
Bioinformatics and Biology Insights     Open Access   (Followers: 14)
Bioinspiration & Biomimetics     Hybrid Journal   (Followers: 6)
Biointerphases     Open Access   (Followers: 1)
Biojournal of Science and Technology     Open Access  
Biologia     Hybrid Journal  
Biologia on-line : Revista de divulgació de la Facultat de Biologia     Open Access  
Biological Bulletin     Partially Free   (Followers: 4)
Biological Control     Hybrid Journal   (Followers: 5)
Biological Invasions     Hybrid Journal   (Followers: 16)
Biological Journal of the Linnean Society     Hybrid Journal   (Followers: 14)
Biological Letters     Open Access   (Followers: 4)
Biological Procedures Online     Open Access  
Biological Psychiatry     Hybrid Journal   (Followers: 41)
Biological Psychology     Hybrid Journal   (Followers: 6)
Biological Research     Open Access  
Biological Rhythm Research     Hybrid Journal   (Followers: 2)
Biological Theory     Hybrid Journal   (Followers: 1)
Biological Trace Element Research     Hybrid Journal  
Biologicals     Full-text available via subscription   (Followers: 9)
Biologics: Targets & Therapy     Open Access   (Followers: 1)
Biologie Aujourd'hui     Full-text available via subscription  
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 44)
Biologija     Open Access  
Biology     Open Access   (Followers: 5)
Biology and Philosophy     Hybrid Journal   (Followers: 16)
Biology Bulletin     Hybrid Journal   (Followers: 1)
Biology Bulletin Reviews     Hybrid Journal  
Biology Direct     Open Access   (Followers: 7)
Biology Letters     Full-text available via subscription   (Followers: 35)
Biology Methods and Protocols     Hybrid Journal  

        1 2 3 4 5 6 7 8 | Last

Journal Cover Annals of Biomedical Engineering
  [SJR: 1.182]   [H-I: 94]   [18 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1573-9686 - ISSN (Online) 0090-6964
   Published by Springer-Verlag Homepage  [2329 journals]
  • Stiffness of Protease Sensitive and Cell Adhesive PEG Hydrogels Promotes
           Neovascularization In Vivo
    • Authors: Ryan M. Schweller; Zi Jun Wu; Bruce Klitzman; Jennifer L. West
      Pages: 1387 - 1398
      Abstract: Materials that support the assembly of new vasculature are critical for regenerative medicine. Controlling the scaffold’s mechanical properties may help to optimize neovascularization within implanted biomaterials. However, reducing the stiffness of synthetic hydrogels usually requires decreasing polymer densities or increasing chain lengths, both of which accelerate degradation. We synthesized enzymatically-degradable poly(ethylene glycol) hydrogels with compressive moduli from 2 to 18 kPa at constant polymer density, chain length, and proteolytic degradability by inserting an allyloxycarbonyl functionality into the polymer backbone. This group competes with acrylates during photopolymerization to alter the crosslink network structure and reduce the hydrogel’s stiffness. Hydrogels that incorporated (soft) or lacked (stiff) this group were implanted subcutaneously in rats to investigate the role of stiffness on host tissue interactions. Changes in tissue integration were quantified after 4 weeks via the hydrogel area replaced by native tissue (tissue area fraction), yielding 0.136 for softer vs. 0.062 for stiffer hydrogels. Including soluble FGF-2 and PDGF-BB improved these responses to 0.164 and 0.089, respectively. Softer gels exhibited greater vascularization with 8.6 microvessels mm−2 compared to stiffer gels at 2.4 microvessels mm−2. Growth factors improved this to 11.2 and 4.9 microvessels mm−2, respectively. Softer hydrogels tended to display more sustained responses, promoting neovascularization and tissue integration in synthetic scaffolds.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1822-8
      Issue No: Vol. 45, No. 6 (2017)
       
  • Proximity of Metastatic Cells Enhances Their Mechanobiological
           Invasiveness
    • Authors: Yulia Merkher; Daphne Weihs
      Pages: 1399 - 1406
      Abstract: A critical step in metastases formation is cancer-cell invasion through tissue. During invasion, cells change morphology and apply forces to their surroundings. We have previously shown that single, metastatic breast-cancer cells will mechanically indent a synthetic, impenetrable polyacrylamide gel with physiological-stiffness in attempted invasion; benign breast cells do not indent the gels. In solid tumors, e.g., breast cancers, metastases occur predominantly by collective cell-invasion. Thus, here we evaluate the effects of cell proximity on mechanical invasiveness, specifically through changes in gel indention. Gel indentation is induced by 56, 33 and 2% (in >1000 cells), respectively, of adjacent high metastatic potential (MP), low MP and benign breast cells, being double the amounts observed in single, well-separated cells. Single cells exhibited a distribution of indentation depths below 10 µm, while adjacent cells also showed a second peak of deeper indentations. The second peak included 65% of indenting high MP cells as compared to 15% in the low MP cells, illustrating the difference in their invasiveness. Thus, proximity of the metastatic cells enhances their mechanical ability to invade, demonstrating why collective cancer-cell migration is likely more efficient. This could potentially provide a rapid, quantitative approach to identify metastatic cells, and to determine their metastatic potential.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1814-8
      Issue No: Vol. 45, No. 6 (2017)
       
  • A Theoretical Study on Inhibition of Melanoma with Controlled and Targeted
           Delivery of siRNA via Skin Using SPACE-EGF
    • Authors: Juanjuan Liu; Weiping Ding; Renquan Ruan; Lili Zou; Ming Chen; Pengfei Wei; Longping Wen
      Pages: 1407 - 1419
      Abstract: Melanoma is a potentially lethal skin cancer with high mortality rate. Recently, the peptide-mediated transdermal delivery of small interference RNA (siRNA) emerges as a promising strategy to treat melanoma by inducing the apoptosis of tumor cells, but the related theoretical model describing the delivery of siRNA under the effect of SPACE-EGF, the growth inhibition of melanoma and the dynamic expanding of the bump on the skin due to the growth of melanoma has not been reported yet. In this article, a theoretical model is developed to describe the percutaneous siRNA delivery mediated by SPACE-EGF to melanoma and the growth inhibition of melanoma. The results present the spatial–temporal distribution of siRNA and the growth of melanoma under the inhibition of siRNA, which shows a good consistency with the experimental results. In addition, this model represents the uplift process of tumors on the skin surface. The model presented here is a useful tool to understand the whole process of the SPACE-EGF-mediated delivery of the siRNA to melanoma through skin, to predict the therapeutic effect, and to optimize the therapeutic strategy, providing valuable references for the treatment of melanoma.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1825-5
      Issue No: Vol. 45, No. 6 (2017)
       
  • Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically
           Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque
           Type on the Outcomes of Endovascular Therapy
    • Authors: Can Gökgöl; Nicolas Diehm; Philippe Büchler
      Pages: 1420 - 1433
      Abstract: Oversizing of the Nitinol stents in the femoro-popliteal arterial tract is commonly performed by clinicians and further encouraged by stent manufacturers. However, in spite of the procedure’s supposed benefits of strong wall apposition and increased luminal gain, its effects on the mechanical behavior of arteries with peripheral arterial disease are not fully clear. In this study, finite element (FE) analyses of endovascular revascularization of an idealized artery with 70% stenosis and three different plaque types have been performed to examine the influence of Nitinol stent oversizing on the arterial stresses and acute lumen gain. The analyses included the simulation of balloon angioplasty to model plaque failure, followed by stent implantation, in which four different oversizing ratios were investigated. Results showed that balloon angioplasty was crucial in determining the stress levels of the artery prior to stent implantation and heavily affected the outcome of endovascular therapy. For all plaque types, Nitinol stent oversizing was found to produce a marginal lumen gain in contrast to a significant increase in arterial stresses. For the arteries with lightly and moderately calcified plaques, oversizing was found to be non-critical; whereas for the arteries with heavily calcified plaques, the procedure should be avoided due to a risk of tissue failure.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1803-y
      Issue No: Vol. 45, No. 6 (2017)
       
  • Computational Parametric Studies Investigating the Global Hemodynamic
           Effects of Applied Apical Torsion for Cardiac Assist
    • Authors: Elaine Soohoo; Lewis K. Waldman; Dennis R. Trumble
      Pages: 1434 - 1448
      Abstract: Healthy hearts have an inherent twisting motion that is caused by large changes in muscle fiber orientation across the myocardial wall and is believed to help lower wall stress and increase cardiac output. It was demonstrated that applied apical torsion (AAT) of the heart could potentially treat congestive heart failure (CHF) by improving hemodynamic function. We report the results of parametric computational experiments where the effects of using a torsional ventricular assist device (tVAD) to treat CHF were examined using a patient-specific bi-ventricular computational model. We examined the effects on global hemodynamics as the device coverage area (CA) and applied rotation angle (ARA) were varied to determine ideal tVAD design parameters. When compared to a baseline, pretreatment CHF model, increases in ARA resulted in moderate to substantial increases in ejection fraction (EF), peak systolic pressures (PSP) and stroke work (SW) with concomitant decreases in end-systolic volumes (ESV). Increases in device CA resulted in increased hemodynamic function. The simulation representing the most aggressive level of cardiac assist yielded significant increases in left ventricular EF and SW, 49 and 72% respectively. Results with this more realistic computational model reinforce previous studies that have demonstrated the potential of AAT for cardiac assist.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1812-x
      Issue No: Vol. 45, No. 6 (2017)
       
  • Hemodynamic Characterization of Peripheral Arterio-venous Malformations
    • Authors: Sabrina Frey; A. Haine; R. Kammer; H. von Tengg-Kobligk; D. Obrist; I. Baumgartner
      Pages: 1449 - 1461
      Abstract: Peripheral arterio-venous malformations (pAVMs) are congenital vascular anomalies that require treatment, due to their severe clinical consequences. The complexity of lesions often leads to misdiagnosis and ill-planned treatments. To improve disease management, we developed a computational model to quantify the hemodynamic effects of key angioarchitectural features of pAVMs. Hemodynamic results were used to predict the transport of contrast agent (CA), which allowed us to compare our findings to digital subtraction angiography (DSA) recordings of patients. The model is based on typical pAVM morphologies and a generic vessel network that represents realistic vascular feeding and draining components related to lesions. A lumped-parameter description of the vessel network was employed to compute blood pressure and flow rates. CA-transport was determined by coupling the model to a 1D advection–diffusion equation. Results show that the extent of hemodynamic effects of pAVMs, such as arterial steal and venous hypertension, strongly depends on the lesion type and its vascular architecture. Dimensions of shunting vessels strongly influence hemodynamic parameters. Our results underline the importance of the dynamics of CA-transport in diagnostic DSA images. In this context, we identified a set of temporal CA-transport parameters, which are indicative of the presence and specific morphology of pAVMs.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1821-9
      Issue No: Vol. 45, No. 6 (2017)
       
  • Impact of Fiber Structure on the Material Stability and Rupture Mechanisms
           of Coronary Atherosclerotic Plaques
    • Authors: Graeham R. Douglas; Adam J. Brown; Jonathan H. Gillard; Martin R. Bennett; Michael P. F. Sutcliffe; Zhongzhao Teng
      Pages: 1462 - 1474
      Abstract: The rupture of an atherosclerotic plaque in the coronary circulation remains the main cause of heart attack. As a fiber-oriented structure, the fiber structure, in particular in the fibrous cap (FC), may affect both loading and material strength in the plaque. However, the role of fiber orientation and dispersion in plaque rupture is unclear. Local orientation and dispersion of fibers were calculated for the shoulder regions, mid FC, and regions with intimal thickening (IT) from histological images of 16 human coronary atherosclerotic lesions. Finite element analysis was performed to assess the effect of these properties on mechanical conditions. Fibers in shoulder regions had markedly reduced alignment (Median [interquartile range] 12.9° [6.6, 18.0], p < 0.05) compared with those in mid FC (6.1° [5.5, 9.0]) and IT regions (6.7° [5.1, 8.6]). Fiber dispersion was highest in shoulders (0.150 [0.121, 0.192]), intermediate in IT (0.119 [0.103, 0.144]), and lowest in mid FC regions (0.093 [0.081, 0.105], p < 0.05). When anisotropic properties were considered, stresses were significantly higher for the mid FC (p = 0.030) and IT regions (p = 0.002) and no difference was found for the shoulder or global regions. Shear (sliding) stress between fibers in each region and their proportion of maximum principal stress were: shoulder (25.8 kPa [17.1, 41.2], 12.4%), mid FC (13.9 kPa [5.8, 29.6], 13.8%), and IT (36.5 kPa [25.9, 47.3], 15.5%). Fiber structure within the FC has a marked effect on principal stresses, resulting in considerable shear stress between fibers. Fiber structure including orientation and dispersion may determine mechanical strength and thus rupture of atherosclerotic plaques.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1827-3
      Issue No: Vol. 45, No. 6 (2017)
       
  • Continuous-Flow Left Ventricular Assist Device Support Improves Myocardial
           Supply:Demand in Chronic Heart Failure
    • Authors: Kevin G. Soucy; Carlo R. Bartoli; Dustin Phillips; Guruprasad A. Giridharan; Michael A. Sobieski; William B. Wead; Robert D. Dowling; Zhongjun J. Wu; Sumanth D. Prabhu; Mark S. Slaughter; Steven C. Koenig
      Pages: 1475 - 1486
      Abstract: Continuous-flow left ventricular assist devices (CF LVADs) are rotary blood pumps that improve mean blood flow, but with potential limitations of non-physiological ventricular volume unloading and diminished vascular pulsatility. In this study, we tested the hypothesis that left ventricular unloading with increasing CF LVAD flow increases myocardial flow normalized to left ventricular work. Healthy (n = 8) and chronic ischemic heart failure (IHF, n = 7) calves were implanted with CF LVADs. Acute hemodynamics and regional myocardial blood flow were measured during baseline (LVAD off, clamped), partial (2–4 L/min) and full (>4 L/min) LVAD support. IHF calves demonstrated greater reduction of cardiac energy demand with increasing LVAD support compared to healthy calves, as calculated by rate-pressure product. Coronary artery flows (p < 0.05) and myocardial blood flow (left ventricle (LV) epicardium and myocardium, p < 0.05) decreased with increasing LVAD support in normal calves. In the IHF model, blood flow to the septum, LV, LV epicardium, and LV myocardium increased significantly with increasing LVAD support when normalized to cardiac energy demand (p < 0.05). In conclusion, myocardial blood flow relative to cardiac demand significantly increased in IHF calves, thereby demonstrating that CF LVAD unloading effectively improves cardiac supply and demand ratio in the setting of ischemic heart failure.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1804-x
      Issue No: Vol. 45, No. 6 (2017)
       
  • A Novel Apparatus for the Multifaceted Evaluation of Arterial Function
           Through Transmural Pressure Manipulation
    • Authors: Toshiyuki Yaguchi; Yalin Cong; Kenji Shimo; Takahiro Kurokawa; Shukei Sugita; Kazuaki Nagayama; Hiroshi Masuda; Takeo Matsumoto
      Pages: 1487 - 1495
      Abstract: A novel apparatus for the multifaceted evaluation of artery function was developed. It measures endothelial and smooth muscle functions and the pressure–strain elastic modulus (E p). A rigid airtight chamber with an ultrasound probe was attached to the upper arm to manipulate the transmural pressure of the brachial artery. Endothelial function was measured via a standard flow-mediated dilation (FMD) protocol. Smooth muscle function was evaluated via a myogenic contraction of the artery following the application of negative pressure to the chamber and was named pressure-mediated contraction (PMC). E p was obtained by measuring the instantaneous increase in the artery diameter following the negative pressure application. The PMC and FMD values had a significant negative correlation with age, indicating that the age-related decrease in FMD is caused by the decay of endothelial and smooth muscle function. A consideration of PMC may help improve the accuracy of artery function measurement. E p in subjects aged >40 years was found to be significantly higher in the supra-physiological pressure range than in the physiological one (p = 0.02); this did not occur in younger subjects. Artery stiffening may begin in the supra-physiological range, and this stiffness may also be used for the diagnosis of atherosclerosis.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1810-z
      Issue No: Vol. 45, No. 6 (2017)
       
  • A Dual-Mode Bioreactor System for Tissue Engineered Vascular Models
    • Authors: N. Bono; S. Meghezi; M. Soncini; M. Piola; D. Mantovani; Gianfranco Beniamino Fiore
      Pages: 1496 - 1510
      Abstract: In the past decades, vascular tissue engineering has made great strides towards bringing engineered vascular tissues to the clinics and, in parallel, obtaining in-lab tools for basic research. Herein, we propose the design of a novel dual-mode bioreactor, useful for the fabrication (construct mode) and in vitro stimulation (culture mode) of collagen-based tubular constructs. Collagen-based gels laden with smooth muscle cells (SMCs) were molded directly within the bioreactor culture chamber. Based on a systematic characterization of the bioreactor culture mode, constructs were subjected to 10% cyclic strain at 0.5 Hz for 5 days. The effects of cyclic stimulation on matrix re-arrangement and biomechanical/viscoelastic properties were examined and compared vs. statically cultured constructs. A thorough comparison of cell response in terms of cell localization and expression of contractile phenotypic markers was carried out as well. We found that cyclic stimulation promoted cell-driven collagen matrix bi-axial compaction, enhancing the mechanical strength of strained samples with respect to static controls. Moreover, cyclic strain positively affected SMC behavior: cells maintained their contractile phenotype and spread uniformly throughout the whole wall thickness. Conversely, static culture induced a noticeable polarization of cell distribution to the outer rim of the constructs and a sharp reduction in total cell density. Overall, coupling the use of a novel dual-mode bioreactor with engineered collagen-gel-based tubular constructs demonstrated to be an interesting technology to investigate the modulation of cell and tissue behavior under controlled mechanically conditioned in vitro maturation.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1813-9
      Issue No: Vol. 45, No. 6 (2017)
       
  • Activity of Erector Spinae During Trunk Forward Bending and Backward
           Return: The Effects of Age
    • Authors: Iman Shojaei; Babak Bazrgari
      Pages: 1511 - 1519
      Abstract: Electromyography (EMG)-based measures of the trunk muscles behavior have been used for objective assessment of biomechanical impairments in patients with low back pain (LBP); yet the literature on normal age-related differences in such measures is scant. A cross-sectional study was designed to assess age-related differences in activity of trunk extensors during forward bending and backward return. Sixty asymptomatic individuals were recruited to form five gender-balanced age groups between 20 and 70 years old. Participants completed two sets of trunk forward bending and backward return task using self-selected and fast motion paces. For bending and return phases of each task, the normalized lumbar flexion angles corresponding to different event times of erector spinae activity along with the peak normalized and non-normalized EMG activities of erector spinae were calculated. The mean normalized and non-normalized EMG activities of erector spinae during the entire task also were calculated. There was no age-related difference in normalized lumbar flexion angles corresponding to different event times of erector spinae activity. However, the peak normalized EMG activity during forward bending and backward return as well as the mean normalized EMG activity during the entire task were found to be larger in older vs. younger individuals. Given the suggested unreliability of normalized EMG in elders and considering that we did not find any age-related differences in non-normalized EMG activity of erector spinae, our results do not strongly support the existence of normal age-related differences in EMG profile of erector spinae during forward bending and backward return. Therefore, when interpreting EMG-based measures of trunk muscles behavior for identification of biomechanical impairment in patients with LBP, potential abnormalities in EMG activity of trunk muscles may not be attributed to patient’s age.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1811-y
      Issue No: Vol. 45, No. 6 (2017)
       
  • Acoustic Emission Signatures During Failure of Vertebra and Long Bone
    • Authors: Brian D. Goodwin; Frank A. Pintar; Narayan Yoganandan
      Pages: 1520 - 1533
      Abstract: Clinical classification of an injury has traditionally involved medical imaging, patient history, and physical examination. The pathogenesis or process of injury has been viewed as a crucial component to estimating fracture stability and direct treatment. However, injury classification systems generally exclude pathogenesis and injury mechanisms because these components are often difficult to elucidate. Furthermore, the development of bone damage relative to the mechanical response is difficult to quantify, which limits the ability to define injury and develop injury criteria. Past advents of new knowledge about the mechanisms and progression of fracture have refined safety standards and engineering design for limiting injury. Post-hoc methodologies for identifying and classifying injuries for post-mortem human surrogate (PMHS) research are well established. Though bone fractures can be classified post hoc, questions remain. Surface acoustic sensing (SAS) is an effective approach to augment PMHS experimentation. The objective was to develop and validate an acoustic-emission-based method to characterize bone fractures during injurious loading conditions using acoustic emissions (AEs) in two bone types: vertebral body (VB) and long bone (LB). The newly developed method incorporated the Stockwell transform to estimate the relative energy release rate (RERR) from bone fracture using acoustic signal processing. Fractures were characterized through AE burst durations and frequency content. Results indicated that VB fractures from compression are prolonged processes compared to LB fracture, which was staccato in nature. Significant (p < 0.01) differences between burst duration and frequency content were identified between the two bone types.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1818-4
      Issue No: Vol. 45, No. 6 (2017)
       
  • The Injury Tolerance of the Tibia Under Off-Axis Impact Loading
    • Authors: Avery B. Chakravarty; Alberto A. Martinez; Cheryl E. Quenneville
      Pages: 1534 - 1542
      Abstract: During a frontal collision, there are a range of lower extremity postures that the vehicle’s occupant may assume, potentially changing the way load is transmitted to this region of the body. While most experimental studies on the tibia’s injury tolerance assume that load is directed along the leg’s long axis, the effects of off-axis loading due to non-standard postures have not been well quantified, and commonly-cited injury criteria such as the Tibia Index do not directly account for posture. Therefore, twelve cadaveric tibias (paired from six donors) were subjected to off-axis impact loading in a custom-built test apparatus. One specimen from each pair was held at an angle of 15° relative to the direction of loading, while the contralateral was held at an angle of 30°, with these angles representing ankle plantarflexion and corresponding knee extension in a vehicle occupant. Specimens held at 30° fractured at lower forces than the specimens held at 15° (mean force = 5.8 vs. 7.5 kN). This indicates that posture should be incorporated into injury criteria for the tibia in future safety assessments instead of using a single force value based on axial impacts.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1824-6
      Issue No: Vol. 45, No. 6 (2017)
       
  • Anisotropic Permeability of Trabecular Bone and its Relationship to Fabric
           and Architecture: A Computational Study
    • Authors: T. C. Kreipke; G. L. Niebur
      Pages: 1543 - 1554
      Abstract: Trabecular bone is a porous, mineralized tissue found in vertebral bodies, the metaphyses and epiphyses of long bones, and in the irregular and flat shaped bones. The pore space is filled with bone marrow, a highly cellular fluid. Together, the bone and marrow behave as a poroelastic solid. In poroelasticity theory, the permeability is the primary material property that governs the momentum transfer between the solid and fluid constituents. In the linearized theory, the permeability of a material depends on the shape and connectivity of the pores. Developing a model of the relationship between trabecular microarchitecture and permeability could lead to improved simulations of trabecular bone mechanical response, which can be used to investigate bone adaptation, mechanobiological signaling, and progression of diseases such as osteoporosis. This study used finite element models of the trabecular pore space to calculate the complete anisotropic permeability tensor of 12 human and 18 porcine femoral trabecular bone samples. The sensitivity of the simulations to model assumptions and post-processing was analyzed to improve confidence in the result. The orthotropic permeability tensor depended on the fabric tensor, trabecular spacing, and structure model index through a power law relationship. Porosity and fabric alone also provided a reasonable prediction, which may be useful in cases where the image resolution is insufficient to obtain detailed measures of architecture.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1805-9
      Issue No: Vol. 45, No. 6 (2017)
       
  • Erratum to: Anisotropic Permeability of Trabecular Bone and Its
           Relationship to Fabric and Architecture: A Computational Study
    • Authors: T. C. Kreipke; G. L. Niebur
      Pages: 1555 - 1559
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1835-3
      Issue No: Vol. 45, No. 6 (2017)
       
  • Linear and Nonlinear Gait Features in Older Adults Walking on Inclined
           Surfaces at Different Speeds
    • Authors: Marcus Fraga Vieira; Fábio Barbosa Rodrigues; Gustavo Souto de Sá e Souza; Rina Márcia Magnani; Georgia Cristina Lehnen; Adriano O. Andrade
      Pages: 1560 - 1571
      Abstract: This study evaluated linear and nonlinear gait features in healthy older adults walking on inclined surfaces at different speeds. Thirty-seven active older adults (experimental group) and fifty young adults (control group) walked on a treadmill at 100% and ±20% of their preferred walking speed for 4 min under horizontal (0%), upward (UP) (+8%), and downward (DOWN) (−8%) conditions. Linear gait variability was assessed using the average standard deviation of trunk acceleration between strides (VAR). Gait stability was assessed using the margin of stability (MoS). Nonlinear gait features were assessed by using the maximum Lyapunov exponent, as a measure of local dynamic stability (LDS), and sample entropy (SEn), as a measure of regularity. VAR increased for all conditions, but the interaction effects between treadmill inclination and age, and speed and age were higher for young adults. DOWN conditions showed the lowest stability in the medial–lateral MoS, but not in LDS. LDS was smaller in UP conditions. However, there were no effects of age for either MoS or LDS. The values of SEn decreased almost linearly from the DOWN to the UP conditions, with significant interaction effects of age for anterior–posterior SEn. The overall results supported the hypothesis that inclined surfaces modulate nonlinear gait features and alter linear gait variability, particularly in UP conditions, but there were no significant effects of age for active older adults.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1820-x
      Issue No: Vol. 45, No. 6 (2017)
       
  • Handheld Electrical Impedance Myography Probe for Assessing Carpal Tunnel
           Syndrome
    • Authors: Zhao Li; Lingfen Chen; Yu Zhu; Qingquan Wei; Wenwen Liu; Dong Tian; Yude Yu
      Pages: 1572 - 1580
      Abstract: Electrical impedance myography (EIM) is a novel, noninvasive, and painless technique for quantitatively assessing muscle health as well as disease status and progression. The preparatory work for commercial adhesive electrodes used in previous EIM measurements is tedious, as the electrodes need to be cut, repeatedly applied, and removed. Moreover, the electrode distances need to be measured many times. To overcome these problems, we developed a convenient and practical handheld EIM probe for assessing carpal tunnel syndrome (CTS) in the small hand muscles. To reduce the electrode–skin contact impedance (ESCI), the micropillared and microholed stainless steel electrodes (SSEs) contained in the probe were fabricated using a laser processing technique. When covered with saline, these electrodes showed lower ESCIs than a smooth SSE and Ag/AgCl electrode. The probe was shown to have excellent test–retest reproducibility in both healthy subjects and CTS patients, with intraclass correlation coefficients exceeding 0.975. The reactance and phase values of the abductor pollicis brevis (affected muscle) for CTS patients were consistently lower than those for healthy subjects, with a 50-kHz difference of 37.1% (p < 0.001) and 31.0% (p < 0.001), respectively. Further, no significant differences were detected in the case of the abductor digiti minimi (unaffected muscle). These results indicate that EIM has considerable potential for CTS assessment and hence merits further investigation.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1819-3
      Issue No: Vol. 45, No. 6 (2017)
       
  • The Interaction of Intramuscular Ketorolac (Toradol) and Concussion in a
           Rat Model
    • Authors: Amanda O. Esquivel; Sarah S. Sherman; Cynthia A. Bir; Stephen E. Lemos
      Pages: 1581 - 1588
      Abstract: The purpose of this study was to examine the interaction of a single dose of Toradol and head impact in an in vivo rat model for sport-related concussion using a validated rat concussion model. Thirty-five Sprague–Dawley rats were placed into one of four groups: (1) Control, (2) Impact Only, (3) Toradol Only, (4) Impact and Toradol. Animals in the impact groups were subjected to a single head impact. Animals in the Toradol group received a single intramuscular injection of Toradol prior to impact. We examined magnetic resonance imaging, serum S100-B and cognitive function using a Morris Water Maze. In the control group, latency decreased significantly from day 0 (74.9 s) to 24 h (57.4 s) after anesthesia. There was no statistically significant difference between time zero and 24 h after impact in the Impact only or Impact and Toradol group. Our findings indicate that there were no differences between cognitive ability, MRI findings or S100B in rats that were administered a single dose of Toradol and subjected to a single impact and rats that were subjected to a single impact only. In both impact groups there were transient changes in cognitive ability as measured by the Morris Water Maze.
      PubDate: 2017-06-01
      DOI: 10.1007/s10439-017-1809-5
      Issue No: Vol. 45, No. 6 (2017)
       
  • Pre-operative Screening and Manual Drilling Strategies to Reduce the Risk
           
    • Authors: Neal P. Dillon; Loris Fichera; Kyle Kesler; M. Geraldine Zuniga; Jason E. Mitchell; Robert J. Webster; Robert F. Labadie
      Abstract: This article presents the development and experimental validation of a methodology to reduce the risk of thermal injury to the facial nerve during minimally invasive cochlear implantation surgery. The first step in this methodology is a pre-operative screening process, in which medical imaging is used to identify those patients that present a significant risk of developing high temperatures at the facial nerve during the drilling phase of the procedure. Such a risk is calculated based on the density of the bone along the drilling path and the thermal conductance between the drilling path and the nerve, and provides a criterion to exclude high-risk patients from receiving the minimally invasive procedure. The second component of the methodology is a drilling strategy for manually-guided drilling near the facial nerve. The strategy utilizes interval drilling and mechanical constraints to enable better control over the procedure and the resulting generation of heat. The approach is tested in fresh cadaver temporal bones using a thermal camera to monitor temperature near the facial nerve. Results indicate that pre-operative screening may successfully exclude high-risk patients and that the proposed drilling strategy enables safe drilling for low-to-moderate risk patients.
      PubDate: 2017-05-18
      DOI: 10.1007/s10439-017-1854-0
       
  • An Intracardiac Soft Robotic Device for Augmentation of Blood Ejection
           from the Failing Right Ventricle
    • Authors: Markus A. Horvath; Isaac Wamala; Eric Rytkin; Elizabeth Doyle; Christopher J. Payne; Thomas Thalhofer; Ignacio Berra; Anna Solovyeva; Mossab Saeed; Sara Hendren; Ellen T. Roche; Pedro J. del Nido; Conor J. Walsh; Nikolay V. Vasilyev
      Abstract: We introduce an implantable intracardiac soft robotic right ventricular ejection device (RVED) for dynamic approximation of the right ventricular (RV) free wall and the interventricular septum (IVS) in synchrony with the cardiac cycle to augment blood ejection in right heart failure (RHF). The RVED is designed for safe and effective intracardiac operation and consists of an anchoring system deployed across the IVS, an RV free wall anchor, and a pneumatic artificial muscle linear actuator that spans the RV chamber between the two anchors. Using a ventricular simulator and a custom controller, we characterized ventricular volume ejection, linear approximation against different loads and the effect of varying device actuation periods on volume ejection. The RVED was then tested in vivo in adult pigs (n = 5). First, we successfully deployed the device into the beating heart under 3D echocardiography guidance (n = 4). Next, we performed a feasibility study to evaluate the device’s ability to augment RV ejection in an experimental model of RHF (n = 1). RVED actuation augmented RV ejection during RHF; while further chronic animal studies will provide details about the efficacy of this support device. These results demonstrate successful design and implementation of the RVED and its deployment into the beating heart. This soft robotic ejection device has potential to serve as a rapidly deployable system for mechanical circulatory assistance in RHF.
      PubDate: 2017-05-16
      DOI: 10.1007/s10439-017-1855-z
       
 
 
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