Subjects -> BIOLOGY (Total: 3492 journals)
    - BIOCHEMISTRY (267 journals)
    - BIOENGINEERING (143 journals)
    - BIOLOGY (1675 journals)
    - BIOPHYSICS (50 journals)
    - BIOTECHNOLOGY (271 journals)
    - BOTANY (254 journals)
    - CYTOLOGY AND HISTOLOGY (32 journals)
    - ENTOMOLOGY (76 journals)
    - GENETICS (171 journals)
    - MICROBIOLOGY (292 journals)
    - MICROSCOPY (12 journals)
    - ORNITHOLOGY (29 journals)
    - PHYSIOLOGY (73 journals)
    - ZOOLOGY (147 journals)

BIOLOGY (1675 journals)            First | 1 2 3 4 5 6 7 8 | Last

Showing 801 - 1000 of 1720 Journals sorted alphabetically
International Journal of Peptide Research and Therapeutics     Partially Free   (Followers: 6)
International Journal of Peptides     Open Access   (Followers: 2)
International Journal of Pharmaceutical and Life Sciences     Open Access   (Followers: 5)
International Journal of Phytopathology     Open Access   (Followers: 5)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 1)
International Journal of Plant Genomics     Open Access   (Followers: 4)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Primatology     Hybrid Journal   (Followers: 7)
International Journal of Reproductive BioMedicine     Open Access   (Followers: 1)
International Journal of Scientific Reports     Open Access   (Followers: 4)
International Journal of Secondary Metabolite     Open Access   (Followers: 2)
International Journal of Signs and Semiotic Systems     Full-text available via subscription  
International Journal of Speleology     Open Access   (Followers: 3)
International Journal of Systems Biology and Biomedical Technologies     Full-text available via subscription   (Followers: 3)
International Journal of Tropical Insect Science     Hybrid Journal   (Followers: 1)
International Journal of Tryptophan Research     Open Access  
International Letters of Natural Sciences     Open Access   (Followers: 2)
International Multidisciplinary Research Journal     Open Access  
International Review of Cell and Molecular Biology     Full-text available via subscription   (Followers: 7)
International Review of Hydrobiology     Hybrid Journal   (Followers: 2)
Intervirology     Full-text available via subscription  
IntraVital     Full-text available via subscription  
Invertebrate Biology     Hybrid Journal   (Followers: 10)
Invertebrate Neuroscience     Hybrid Journal   (Followers: 4)
Invertebrate Systematics     Hybrid Journal   (Followers: 8)
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Iranian Journal of Parasitology     Open Access   (Followers: 2)
IRBM     Full-text available via subscription  
IRBM News     Full-text available via subscription  
iScience     Open Access  
Islets     Full-text available via subscription   (Followers: 1)
Israel Journal of Ecology and Evolution     Full-text available via subscription   (Followers: 1)
Istituto Lombardo - Accademia di Scienze e Lettere - Incontri di Studio     Open Access  
Italian Journal of Mycology     Open Access  
ITBM-RBM     Full-text available via subscription   (Followers: 1)
ITBM-RBM News     Full-text available via subscription   (Followers: 1)
IUBMB Life     Hybrid Journal   (Followers: 6)
IUFS Journal of Biology     Open Access  
Izvestiya, Atmospheric and Oceanic Physics     Full-text available via subscription   (Followers: 1)
Izvestiya, Physics of the Solid Earth     Hybrid Journal   (Followers: 2)
Jahangirnagar University Journal of Biological Sciences     Open Access   (Followers: 1)
Japanese Journal of Applied Physics     Full-text available via subscription   (Followers: 6)
JCI Insight     Open Access   (Followers: 3)
JDREAM : Journal of interDisciplinary REsearch Applied to Medicine     Open Access  
JETP Letters     Hybrid Journal   (Followers: 3)
JKI Datenblätter : Pflanzenkrankheiten und Diagnose     Open Access   (Followers: 2)
Jornal Interdisciplinar de Biociências     Open Access  
Journal Biastatistics : Biomedics, Industry & Business And Social Statistics     Open Access  
Journal of Bacteriology & Parasitology     Open Access   (Followers: 5)
Journal of Bioanalysis & Biomedicine     Open Access   (Followers: 1)
Journal of Bioequivalence & Bioavailability     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 4)
Journal of Computer Science & Systems Biology     Open Access   (Followers: 5)
Journal of Proteomics & Bioinformatics     Open Access   (Followers: 10)
Journal of Advanced Laboratory Research in Biology     Open Access   (Followers: 1)
Journal of Advances in Biology     Open Access   (Followers: 5)
Journal of Advances in Biology & Biotechnology     Open Access   (Followers: 1)
Journal of Agricultural, Biological & Environmental Statistics     Hybrid Journal   (Followers: 11)
Journal of Al-Qadisiyah for Pure Science     Open Access   (Followers: 1)
Journal of Amino Acids     Open Access   (Followers: 4)
Journal of Anatomy     Hybrid Journal   (Followers: 7)
Journal of AOAC International     Full-text available via subscription   (Followers: 8)
Journal of Applied Biobehavioral Research     Hybrid Journal  
Journal of Applied Bioinformatics & Computational Biology     Hybrid Journal   (Followers: 5)
Journal of Applied Biological Sciences     Open Access   (Followers: 2)
Journal of Applied Biosciences     Open Access   (Followers: 2)
Journal of Applied Ichthyology     Hybrid Journal   (Followers: 6)
Journal of Applied Life Sciences International     Open Access   (Followers: 1)
Journal of Applied Phycology     Hybrid Journal   (Followers: 10)
Journal of Applied Virology     Open Access   (Followers: 5)
Journal of Aquatic Sciences     Full-text available via subscription   (Followers: 3)
Journal of Arachnology     Full-text available via subscription  
Journal of Asia-Pacific Biodiversity     Open Access  
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Avian Biology     Hybrid Journal   (Followers: 24)
Journal of Basic Microbiology     Hybrid Journal   (Followers: 3)
Journal of Bio-Science     Open Access   (Followers: 3)
Journal of Bio-X Research     Open Access   (Followers: 1)
Journal of Biobased Materials and Bioenergy     Full-text available via subscription  
Journal of Biocommunication     Open Access   (Followers: 2)
Journal of Biodiversity Management & Forestry     Hybrid Journal   (Followers: 6)
Journal of Bioenergetics and Biomembranes     Hybrid Journal   (Followers: 1)
Journal of Biogeography     Hybrid Journal   (Followers: 45)
Journal of Bioinformatics and Computational Biology     Hybrid Journal   (Followers: 19)
Journal of Bioinformatics and Intelligent Control     Full-text available via subscription   (Followers: 2)
Journal of Bioinformatics and Sequence Analysis     Open Access   (Followers: 1)
Journal of Biological Control     Hybrid Journal   (Followers: 2)
Journal of Biological Dynamics     Open Access   (Followers: 1)
Journal of Biological Education     Hybrid Journal   (Followers: 2)
Journal of Biological Engineering     Open Access   (Followers: 3)
Journal of Biological Methods     Open Access  
Journal of Biological Physics     Hybrid Journal   (Followers: 1)
Journal of Biological Research - Thessaloniki     Open Access  
Journal of Biological Sciences     Open Access   (Followers: 5)
Journal of Biological Systems     Hybrid Journal   (Followers: 2)
Journal of Biology and Life Science     Open Access   (Followers: 2)
Journal of Biology, Agriculture and Healthcare     Open Access   (Followers: 11)
Journal of Biomechanics     Hybrid Journal   (Followers: 42)
Journal of Biomedical Education     Open Access   (Followers: 2)
Journal of Biomedical Informatics     Partially Free   (Followers: 16)
Journal of Biomedical Informatics : X     Open Access  
Journal of Biomedical Materials Research Part A     Hybrid Journal   (Followers: 3)
Journal of Biomedical Materials Research Part B : Applied Biomaterials     Hybrid Journal   (Followers: 2)
Journal of Biomedical Nanotechnology     Full-text available via subscription   (Followers: 3)
Journal of Biomedical Physics and Engineering     Open Access  
Journal of Biomedical Science and Engineering     Open Access   (Followers: 2)
Journal of Bionic Engineering     Hybrid Journal  
Journal of Bioresource Management     Open Access  
Journal of Biorheology     Hybrid Journal  
Journal of Biosafety and Biosecurity     Open Access  
Journal of Bioscience and Bioengineering     Full-text available via subscription   (Followers: 31)
Journal of Biosciences and Medicines     Open Access   (Followers: 3)
Journal of Biosocial Science     Hybrid Journal   (Followers: 5)
Journal of Bryology     Hybrid Journal   (Followers: 7)
Journal of Cell Biology     Full-text available via subscription   (Followers: 49)
Journal of Cell Communication and Signaling     Hybrid Journal  
Journal of Cell Death     Open Access   (Followers: 2)
Journal of Cell Science     Full-text available via subscription   (Followers: 18)
Journal of Cellular Biochemistry     Hybrid Journal   (Followers: 4)
Journal of Cellular Physiology     Hybrid Journal   (Followers: 7)
Journal of Cerebral Blood Flow & Metabolism     Hybrid Journal   (Followers: 2)
Journal of Chromatography B     Hybrid Journal   (Followers: 35)
Journal of Clinical Bioinformatics     Open Access   (Followers: 5)
Journal of Clinical Toxicology     Open Access   (Followers: 6)
Journal of Communications Technology and Electronics     Hybrid Journal   (Followers: 2)
Journal of Contemporary Physics (Armenian Academy of Sciences)     Hybrid Journal   (Followers: 10)
Journal of Crustacean Biology     Hybrid Journal   (Followers: 3)
Journal of Developmental Biology     Open Access   (Followers: 2)
Journal of Ecology and The Natural Environment     Open Access   (Followers: 4)
Journal of Education, Health and Sport     Open Access   (Followers: 4)
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electromyography and Kinesiology     Hybrid Journal   (Followers: 5)
Journal of Environment and Ecology     Open Access   (Followers: 10)
Journal of Environment and Sociobiology     Hybrid Journal   (Followers: 1)
Journal of Environmental Analysis and Progress     Open Access  
Journal of Environmental Radioactivity     Hybrid Journal   (Followers: 3)
Journal of Environmental Science and Natural Resources     Open Access   (Followers: 4)
Journal of Ethnobiology     Full-text available via subscription   (Followers: 4)
Journal of Ethnobiology and Ethnomedicine     Open Access  
Journal of Ethology     Hybrid Journal   (Followers: 3)
Journal of Evolutionary Biology     Hybrid Journal   (Followers: 26)
Journal of Evolutionary Biology Research     Open Access  
Journal of Experimental and Clinical Anatomy     Open Access   (Followers: 2)
Journal of Experimental Life Science     Open Access  
Journal of Experimental Marine Biology and Ecology     Hybrid Journal   (Followers: 41)
Journal of Fish Biology     Hybrid Journal   (Followers: 36)
Journal of Functional Biomaterials     Open Access   (Followers: 3)
Journal of Fungi     Open Access   (Followers: 3)
Journal of Genomics     Open Access   (Followers: 1)
Journal of Great Lakes Research     Hybrid Journal   (Followers: 7)
Journal of Green Science and Technology     Full-text available via subscription   (Followers: 2)
Journal of Health and Biological Sciences     Open Access   (Followers: 1)
Journal of Heredity     Hybrid Journal   (Followers: 4)
Journal of Huazhong University of Science and Technology [Medical Sciences]     Hybrid Journal  
Journal of Human Evolution     Hybrid Journal   (Followers: 18)
Journal of Hymenoptera Research     Open Access   (Followers: 3)
Journal of Ichthyology     Full-text available via subscription   (Followers: 3)
Journal of Insect Behavior     Hybrid Journal   (Followers: 7)
Journal of Insect Biodiversity     Open Access   (Followers: 4)
Journal of Insect Conservation     Hybrid Journal   (Followers: 11)
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated OMICS     Open Access  
Journal of Integrated Pest Management     Open Access   (Followers: 3)
Journal of Integrative Environmental Sciences     Hybrid Journal   (Followers: 4)
Journal of Intelligent Transportation Systems: Technology, Planning, and Operations     Hybrid Journal   (Followers: 4)
Journal of Invertebrate Pathology     Hybrid Journal   (Followers: 3)
Journal of Kerbala University     Open Access   (Followers: 1)
Journal of Landscape Ecology     Open Access   (Followers: 20)
Journal of Law and the Biosciences     Open Access   (Followers: 5)
Journal of Leukocyte Biology     Open Access   (Followers: 2)
Journal of Life and Earth Science     Open Access  
Journal of Life Sciences Research     Open Access  
Journal of Lipid Research     Full-text available via subscription   (Followers: 6)
Journal of Lipids     Open Access  
Journal of Luminescence     Hybrid Journal   (Followers: 5)
Journal of Mammalian Evolution     Hybrid Journal   (Followers: 7)
Journal of Mammalian Ova Research     Full-text available via subscription  
Journal of Mammalogy     Full-text available via subscription   (Followers: 16)
Journal of Mammary Gland Biology and Neoplasia     Hybrid Journal   (Followers: 1)
Journal of Marine and Aquatic Sciences     Open Access   (Followers: 1)
Journal of Marine Sciences     Open Access   (Followers: 17)
Journal of Mathematical Biology     Hybrid Journal   (Followers: 8)
Journal of Mechanics in Medicine and Biology     Hybrid Journal  
Journal of Medical Primatology     Hybrid Journal   (Followers: 1)
Journal of Medical Toxicology     Hybrid Journal   (Followers: 6)
Journal of Medicinal Botany     Open Access  
Journal of Medicine and Philosophy     Hybrid Journal   (Followers: 8)
Journal of Melittology     Open Access   (Followers: 1)
Journal of Membrane Biology     Hybrid Journal   (Followers: 1)
Journal of Membrane Computing     Hybrid Journal  
Journal of Membrane Science     Hybrid Journal   (Followers: 25)
Journal of Metabolomics & Systems Biology     Open Access   (Followers: 2)
Journal of Molecular Biology     Hybrid Journal   (Followers: 45)
Journal of Molecular Biology Research     Open Access   (Followers: 3)
Journal of Molecular Catalysis B: Enzymatic     Hybrid Journal   (Followers: 1)
Journal of Molecular Cell Biology     Hybrid Journal   (Followers: 14)
Journal of Molecular Evolution     Hybrid Journal   (Followers: 6)
Journal of Molecular Signaling     Open Access  
Journal of Molecular Structure     Hybrid Journal   (Followers: 7)

  First | 1 2 3 4 5 6 7 8 | Last

Similar Journals
Journal Cover
Journal of Biorheology
Journal Prestige (SJR): 0.148
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1867-0474 - ISSN (Online) 1867-0466
Published by Springer-Verlag Homepage  [2626 journals]
  • Commentary on Shu Chien’s 2011 National Medal of Science Award:
           Buddha of a bioengineer
    • Authors: G. S. Kassab
      Pages: 1 - 2
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0047-6
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Fluid mechanical and electrostatic study on the osmotic flow through
           cylindrical pores
    • Authors: Takeshi Akinaga; Masako Sugihara-Seki
      Pages: 3 - 10
      Abstract: Abstract When two solutions differing in solute concentration are separated by a porous membrane, the osmotic pressure will generate a net volume flux of the suspending fluid across the membrane; this is termed osmotic flow. We consider the osmotic flow across a membrane with circular cylindrical pores when the solute and the pore walls are electrically charged, and the suspending fluid is an electrolytic solution containing small cations and anions. Under the condition in which the radius of the pores and that of the solute molecules greatly exceed those of the solvent as well as the ions, a fluid mechanical and electrostatic theory is introduced to describe the osmotic flow in the presence of electric charge. The interaction energy, including the electrostatic interaction between the solute and the pore wall, plays a key role in determining the osmotic flow. We examine the electrostatic effect on the osmotic flow and discuss the difference in the interaction energy determined from the nonlinear Poisson-Boltzmann equation and from its linearized equation (the Debye-Hückel equation).
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0049-4
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Drift and fluctuating motion of artificial platelets during the lateral
           transport and adhesion process near the wall
    • Authors: Hiroaki Tobimatsu; Antoine Paragon; Yosuke Okamura; Shinji Takeoka; Ryo Sudo; Yasuo Ikeda; Kazuo Tanishita
      Pages: 11 - 20
      Abstract: Abstract Recombinant glycoprotein Ibα latex beads (rGPIbα-LB) are a potential solution to overcoming platelet transfusion problems with artificial platelets. To understand the transport process of artificial platelets and to estimate the particle motion when adhering to the wall surface, we evaluated the lateral motion of rGPIbα-LB in terms of drift and random motion, because the lateral motion is an important factor for transport and adhesion. We observed the lateral motion of rGPIbα-LB flowing with red blood cells toward the immobilized von Willebrand factor (vWf) surface in a model arteriole at wall shear rates of 200–1000 s−1 and 0–40% Hct. At 40% Hct, wall shear rate dependence was observed for the drift motion, i.e. the lateral velocity of rGPIbα-LB toward the wall. In the near-wall region, the drift motion of contacting particles differed substantially from that of non-contacting particles. Additionally, the trajectories of contacting particles on the vWf surface had specific motion that was not observed on the BSA surface. These results suggest that the adhesion force between rGPIbα and vWf is highly associated with the motion of particles near the wall. These features are desirable for artificial platelets, particularly for the adhesion process.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-011-0042-3
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Change in the viscoelastic properties of agarose gel by HAp precipitation
           by osteoblasts cultured in an agarose gel matrix
    • Authors: Yohei Hanazaki; Daisuke Ito; Kazuya Furusawa; Akimasa Fukui; Naoki Sasaki
      Pages: 21 - 28
      Abstract: Abstract The viscoelastic properties of cell-seeded agarose gel were measured as a function of culture time. Because the seeded cells, MC3T3-E1, were osteoblast-like cells, the system can be regarded as a model osteogenesis system. For all specimens the characteristic stress relaxation curve of agarose gel was observed—a large relaxation up to 104 s followed by a gel plateau, where the former was attributed to molecular motion of polymer chains between two adjacent cross-links of the gel and the latter to the elasticity of the gel network. The viscoelasticity was quantified by fitting stress relaxation data to an empirical equation. The relaxation time and its distribution did not change with culture time. The initial and equilibrium moduli, E 0 and E e, respectively, and relaxation strength, ΔE = E 0 − E e, did not change up to day 15 of culture but changed significantly at day 18 of culture. The change in ΔE with culture period correlated well with that in E 0. The changes in the mechanical properties of the cell-seeded agarose gel system were explained in terms of the function of MC3T3-E1 in precipitating calcium phosphate mineral particles. The precipitation was detected by alizarin red S staining of the system at day 9 of culture. The precipitated calcium phosphate was confirmed to be hydroxyapatite (HAp) and the amount of HAp increased monotonically with culturing time, both of which were observed by X-ray diffraction studies. The dependence of the modulus of the composite on mineral fraction is discussed. A simple model of mixing of the components based on the continuum material concept was not applicable, but a model considering percolation of mineral particles in a network chain with culture time was suitable to explain the observed results. The results may be particularly important for predicting the stiffness of functionally engineered bony tissue implanted in a fractured bone.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-011-0043-2
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Load-dispersing design with twined-spring geometry of a distensible
           intracranial stent for cerebral aneurysms
    • Authors: Yasuhiro Shobayashi; Satoshi Tateshima; Kazuo Tanishita
      Pages: 29 - 37
      Abstract: Abstract Endovascular stents are increasingly being used to treat cerebral aneurysms. Mechanically, a cerebrovascular stent must have a low radial stiffness to prevent vessel dissection and rupture. To minimize these complications, we need to consider a stent design that has a low radial force and disperses the load within the stented artery. Therefore, highly distensible, load-dispersion stent designs are desirable for intracranial stenting. This study focused on closed-cell stent geometries and calculated the differences in stress within the artery because of the structure by using finite-element modeling. The results showed that the design with hexagonal cell geometry stretched in the circumferential direction had lower radial and circumferential stresses than did the other models. Comparing the maximum radial stress of our models, stress reduction of 35% was obtained with this design. Moreover, its radial stress was 47 kPa, which was similar to the critical stress of 42 kPa assumed in this study. This stent model was characterized by narrow strut spacing and a large surface area, which was dominated by the twined-spring geometry. It had low radial and circumferential stresses and a dispersed stress distribution compared with the other models. Therefore, this design is a desirable load-dispersing design for cerebrovascular treatment.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-011-0044-1
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Albumin permeability across endothelial monolayers under pulsatile shear
           stress
    • Authors: Susumu Kudo; Minoru Kawarabayashi; Mariko Ikeda; Kazuo Tanishita
      Pages: 38 - 43
      Abstract: Abstract Recent studies suggest that the temporal gradient of shear stress that is generated by blood flow plays an important role in the pathology of arteriosclerosis. We focused on the temporal gradient of shear stress and measured the permeability of albumin under steady or pulsatile shear stress conditions. Porcine aortic endothelial cells were seeded on a membrane filter and subjected to steady or pulsatile shear stress (1 Hz) at 1 Pa for 48 h, and the permeability of albumin was measured over time. The permeability increased gradually under steady flow but increased acutely under pulsatile shear stress. In particular, the maximum permeability of albumin differed under these conditions. The value was 4.2 × 10−5 cm/s at 18 h under pulsatile shear stress and 2.8 × 10−5 cm/s at 48 h under steady shear stress. The permeable route of albumin was examined using isoproterenol, which decreases junctional permeability. The increase in albumin permeability with pulsatile shear stress was decreased by isoproterenol. These results suggest that the increased permeability of albumin with pulsatile shear stress was related to trafficking through paracellular junctions. Thus, pulsation may promote a mechanotransduction process that differs from that of steady shear stress, and these pulsation effects likely play an important role in the permeability of macromolecules.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0045-8
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Influence of segmentation on morphological parameters and computed
           hemodynamics in cerebral aneurysms
    • Authors: Luca Augsburger; Philippe Reymond; Rafik Ouared; Olivier Brina; Daniel A. Rufenacht; Vitor Mendes Pereira; Nikos Stergiopulos
      Pages: 44 - 57
      Abstract: Abstract This article focuses on the effects of segmentation on cerebral aneurysm's morphological parameters and on blood flow patterns computed using computational fluid dynamics. Segmentation is a non-negligible source of uncertainty that may have a consequent impact on the morphological assessment and the resulting hemodynamical simulations, the latter potentially being a key element in the decision-making therapeutic armamentarium for neuroradiologists and neurosurgeons. From the three patient-specific cases investigated, medical imaging data sets were collected, and four different three-dimensional segmentations were generated by the same senior technician. Morphological parameters were measured, and the aspect ratio was derived. Numerical simulations were performed; flow pattern changes, their impact on wall shear stress (WSS) and their sensitivity within the four reconstructed geometries were analyzed. Aneurysm velocity, vorticity and shear magnitudes were computed and compared. The morphological parameters having the highest variability were the aneurysm lobe dimensions (20 %). The neck length was the second parameter presenting the highest variability (21 %). The neck width variability reached 13.8 %, and the aspect ratio variability reached 14.2 %. The artery height and the artery width presented a variability of 13.7 and 10.8 %, respectively. Finally, the aneurysm depth, aneurysm height and aneurysm width presented variabilities of 12.8, 9.4 and 7.3 %, respectively. Differences in the flow path lines, velocity magnitude, wall shear stress and vorticity are also reported and discussed. The average variability reached 15.6 % for velocity, 25.2 % for vorticity and 25.2 % for shear, these parameters being computed inside the aneurysm. The maximum variability reached 31.0 % for velocity, 54.8 % for vorticity and 58.1 % for shear. A segmentation process reconstructing anatomies that is less sensitive to human intervention would be a future goal worth pursuing.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0046-7
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Dynamic visco-elastic buckling analysis of an in vitro airway model:
           prediction of circumferential and axial buckling mode numbers
    • Authors: Kiyoshi Bando; Kenkichi Ohba
      Pages: 58 - 68
      Abstract: Abstract The purpose of the research reported here was to elucidate the mechanism of formation of the various lobes observed in asthmatic airways by both theoretical and experimental analysis employing an in vitro airway model. The rationale is that the elucidated mechanism will facilitate the development of new diagnostic methods and treatment regimens for asthma. Lobe formation was analyzed on the basis of an assumption of cross-sectional buckling of the airway. Here, we propose a dynamic visco-elastic buckling model analysis of the airway for the prediction of circumferential and axial buckling mode numbers. The calculated circumferential buckling mode numbers were in reasonably good agreement with those measured in the dynamic buckling experiment using the in vitro airway model. The calculated axial buckling mode numbers were in qualitative agreement with those observed in the experiment. The non-dimensional parameters related to the remodeling and the consequent pathologies occurring in asthmatic airways were also shown, and the influence of changes in the non-dimensional parameters on the circumferential and axial buckling mode numbers was also calculated. The circumferential and axial buckling mode numbers decreased due to thickening and stiffening of the basement membrane. Thickening of the tissues surrounding the basement membrane and the increase in the mucus secreted in the airway lumen were modeled as an increase in the added mass on the basement membrane. The results of calculation showed that the circumferential and axial buckling mode numbers increased because of the thickening of the surrounding tissues and the increase in mucus secretion. We suggest that it may be possible to diagnose the severity of asthma by using the results of the calculation of the changes in the buckling mode numbers caused by the changes in the strength of the remodeling. The physiological reality of the in vitro airway model reported here is discussed using the non-dimensional parameters.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0050-y
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Estimation of viscosity from passage time of liquids flowing through a
           microchannel array
    • Authors: Yasuyuki Maki; Yumeno Endo; Miyako Fukushima; Mayumi Nishiyama; Toshiaki Dobashi; Hiroyuki Sumino; Masami Murakami
      Pages: 69 - 73
      Abstract: Abstract Recently, a microchannel flow analyzer (MC-FAN) has been used to study the flow properties of blood. However, the correlation between blood passage time measured by use of the MC-FAN and hemorheology has not been clarified. In this study, a simple model is proposed for estimation of liquid viscosity from the passage time t p of liquids. The t p data for physiological saline were well represented by the model. According to the model, the viscosity of Newtonian fluids was estimated reasonably well from the t p data. For blood samples, although the viscosity $ \eta_{\text{mc}} $ estimated from t p was shown to be smaller than the viscosity $ \eta_{{450{\text{s}}^{ - 1} }} $ measured by use of a rotatory viscometer at a shear rate of 450 s−1, $ \eta_{\text{mc}} $ was correlated with $ \eta_{{450{\text{s}}^{ - 1} }} $ . An empirical equation for estimation of $ \eta_{{450{\text{s}}^{ - 1} }} $ from $ \eta_{\text{mc}} $ of blood samples is proposed.
      PubDate: 2013-03-01
      DOI: 10.1007/s12573-012-0048-5
      Issue No: Vol. 26, No. 1-2 (2013)
       
  • Measurement and analysis of the shape recovery process of each erythrocyte
           for estimation of its deformability using the microchannel technique: the
           influence of the softness of the cell membrane and viscosity of the
           hemoglobin solution inside the cell
    • Authors: Tsutomu Tajikawa; Yuya Imamura; Takaya Ohno; Fumiya Muranishi; Maki Kubota; Kenkichi Ohba
      Pages: 1 - 8
      Abstract: Abstract This study tried to evaluate the deformability of each erythrocyte by measuring the time constant of shape recovery just after the erythrocytes left the microchannels. We fabricated a microchannel array with a 5μm-square, 100μm-long cross-section on a PDMS sheet. Three different kinds of blood samples were prepared—healthy erythrocytes as a control, artificially membrane-hardened erythrocytes and artificial hemoglobin solution-diluted erythrocytes—to investigate the influence of erythrocyte's mechanical property changes on the time constant of shape recovery. These shape recovery processes were modeled and analyzed by a standard liner solid model. As a result, the temporal variation of the compressive strain of all erythrocytes showed exponential decay with time elapsed like a first order lag system, so the time constant of shape recovery could be calculated from the semi-logarithmic relaxation curve. The stiffer the cell membrane was using glutaraldehyde, the shorter the time constant for relaxation became compared to healthy erythrocytes. The diluted hemoglobin erythrocytes snapped back quicker than healthy ones. In addition, the time constant of healthy blood drawn from females was clearly shorter than that collected from males. However, the time constant of fully hemoglobin substituted erythrocytes was not affected by gender difference. These results indicate that there is not a significant difference in the stiffness of healthy cell membranes regardless of individual and gender differences. On the other hand, the viscosity of the hemoglobin solution inside the cell is one of the significant factors affecting the time constant. Therefore, these results suggest that the deformability of individual erythrocytes can be quantitated by the time constant for relaxation measured by microchannel techniques.
      PubDate: 2012-08-01
      DOI: 10.1007/s12573-012-0052-9
      Issue No: Vol. 27, No. 1-2 (2012)
       
  • Low pressure condition of a lipid core in an eccentrically developed
           carotid atheromatous plaque: a static finite element analysis
    • Authors: Hiroshi Yamada; Noriyuki Sakata
      Pages: 9 - 17
      Abstract: Abstract Plaque ruptures in atherosclerotic carotid arteries cause cerebral strokes. Accumulation of lipoproteins in the deep intimal layer forms a lipid core (LC), whose progression may be enhanced by mechanical conditions on the arterial wall. In this study, we investigated the pressure conditions of a liquid LC through numerical simulations of a sliced segment finite element (FE) model and a three-dimensional (3D) symmetric FE model. A model of an LC filled with nearly incompressible fluid was compared with incompressible and soft neo-Hookean LC models in a static FE analysis. Material constants for a nonlinear hyperelastic model of the arterial wall were identified based on an inflation test using a tube specimen. The results from the FE analysis of a sliced segment model show an LC fluid pressure as low as 1.9 kPa at a blood pressure of 16 kPa. A neo-Hookean LC model with a Young’s modulus of 0.06 kPa produced an almost uniform pressure in the LC within an error of 1.3 %. The 3D model predicted a similar level of LC pressure. Such low fluid pressure in the LC region may enhance the infiltration of lipoproteins and other substances from the lumen and facilitate transport through microvessels from the adventitia to the LC.
      PubDate: 2012-08-01
      DOI: 10.1007/s12573-012-0051-x
      Issue No: Vol. 27, No. 1-2 (2012)
       
  • Deformation analysis of microcapsules compressed by two rigid parallel
           plates
    • Authors: Kiyoshi Bando; Kenkichi Ohba; Yuta Oiso
      Pages: 18 - 25
      Abstract: Abstract Alginate-poly(l)lysine-alginate microcapsules with a diameter of 200–300 μm were produced and subjected to compression experiments using two rigid parallel plates. The deformed shape was observed, and the relationship between the applied force and the displacement of the plate was measured. A practical analysis method is proposed for the prediction of mechanical properties of microcapsules, namely, the changes in force, transmural pressure, and deformed shape due to the change in the displacement of the plate. The analysis is based on a microcapsule model comprising an axi-symmetric elastic membrane with a constant capsule volume during deformation. Young’s modulus of the membrane, which is used in the analysis, was determined by applying the Hertz contact theory to the experimental results obtained by using an atomic force microscope. The bending stiffness and permeability of the membrane as well as the frictional force between the membrane and the plate were neglected in the analysis. A non-dimensional relationship between the applied force and the displacement of the plate was shown. The theoretically predicted compression force was smaller than the experimentally measured force in the small displacement region, whereas both forces were in good agreement in the large displacement region. The effects of change in Poisson’s ratio, which varied from 0 to 0.5, on the force, transmural pressure, and deformed shape were shown. Under the same displacement conditions, it was observed that the calculated deformed shape was almost coincident with the shape observed in the experiment.
      PubDate: 2012-08-01
      DOI: 10.1007/s12573-012-0053-8
      Issue No: Vol. 27, No. 1-2 (2012)
       
  • An anisotropic viscous hyperelastic constitutive law for brain material
           finite-element modeling
    • Authors: Simon Chatelin; Caroline Deck; Rémy Willinger
      Pages: 26 - 37
      Abstract: Recent experimental studies have highlighted the significant influence of axonal fibers on the nonlinear and anisotropic behavior of brain tissue. This study aims to implement these properties in a transversely isotropic visco-hyperelastic constitutive law for brain tissue. The second step consists in implementation of this law under finite-element (FE) code to improve brain FE modeling by including brain tissue specificities proposed in the recent literature. Validation of the model is shown by comparison of numerical simulation of unconfined compression with experimental tests from the literature. This study represents a step toward more realistic brain FE modeling. Graphical
      PubDate: 2012-12-01
      DOI: 10.1007/s12573-012-0055-6
      Issue No: Vol. 27, No. 1-2 (2012)
       
  • Steady and pulsatile shear stress induce different three-dimensional
           endothelial networks through pseudopodium formation
    • Authors: Yoshinori Abe; Ryo Sudo; Mariko Ikeda; Kazuo Tanishita
      Pages: 38 - 48
      Abstract: Abstract Control of angiogenesis is a major challenge to promotion of vascularization in the field of tissue engineering. In particular, shear stress is recognized as an important mechanical factor controlling new vessel formation. However, the effects of steady and pulsatile shear stress on endothelial cell (EC) network formation remain unclear. Here, we systematically investigated their effects. Compared with pulsatile shear stress, steady shear stress at 1.0 Pa increased cell numbers in EC networks as well as the distribution of networks and pseudopodia in the deep range after 48 h. To further investigate the process of EC network growth, we focused on the effect of flow frequency on network elongation dynamics. Pulsatile shear stress at 1.0 Pa increased the extension and retraction velocities and separation of networks, resulting in the formation of unstable EC networks. In contrast, steady shear stress application resulted in the formation of extended and stable EC networks composed of many cells. Thus, two types of three-dimensional network growth were observed, depending on flow pulsatility. A combination of the type of ECs, such as aortic and microvascular ECs, and flow characteristics, such as flow magnitude and frequency, may have important implications for the construction of well-developed three-dimensional EC networks.
      PubDate: 2012-12-01
      DOI: 10.1007/s12573-012-0056-5
      Issue No: Vol. 27, No. 1-2 (2012)
       
  • Erratum to: Measurement and analysis of the shape recovery process of each
           erythrocyte for estimation of its deformability using the microchannel
           technique: the influence of the softness of the cell membrane and
           viscosity of the hemoglobin solution inside the cell
    • Authors: Tsutomu Tajikawa; Yuya Imamura; Takaya Ohno; Fumiya Muranishi; Maki Kubota; Kenkichi Ohba
      Pages: 49 - 49
      PubDate: 2012-08-01
      DOI: 10.1007/s12573-012-0054-7
      Issue No: Vol. 27, No. 1-2 (2012)
       
 
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