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  • Cell & Developmental Biology
  • Elasticity
  • Inorganic Chemistry
  • Springer  (12)
  • Technische Universität Clausthal-Zellerfeld, Math.-Naturwiss. Fakultät  (1)
  • 1990-1994  (13)
  • 1935-1939
  • 1
    Electronic Resource
    Electronic Resource
    Effects of magnesium deficiency on strength, mass, and composition of rat femur (1994)
    Springer
    Calcified tissue international 54 (1994), S. 44-49 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Stress ; Elasticity ; Mechanical properties ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Magnesium (Mg) participates in the normal formation and remodeling of bone. However, little is known about effects of Mg status on the biomechanical function of bone. We examined gross morphometry and composition as well as biomechanical properties of the femurs of male rats fed diets adequate or deficient in Mg. Comparison of deficient animals and controls yielded a number of differences (all significant at P〈0.05). Mg-depleted animals exhibited slow growth, inefficient food utilization, and greatly reduced concentrations of Mg in both serum and femur ash. Compared with controls, femurs from depleted animals were shorter, but wet weights, diameters, and midfemoral cross-sectional areas showed no differences. Bone length was reduced to a greater degree than could be accounted for by differences in body weights between the groups. Bones of Mg-deficient rats contained less dry matter and less ash (which contained more Ca/g) than those of controls, along with a higher percentage of moisture. Significantly reduced bone strength in depleted animals was evident from the lighter loads supported at the elastic limit (yield point) and at fracture and from decreased stresses accompanying those loads. Modulus of elasticity, however, was not affected by Mg depletion. Different yield and breaking loads were related to different body weights of groups, but stresses were reduced for deficient bones even after adjusting for body size. Our data establish abnormal biomechanical behavior of cortical bone in Mg-deficient animals and emphasize the importance of measuring such functional properties of bone in the assessment of responses to altered metabolic conditions under experimental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316289
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  • 2
    Electronic Resource
    Electronic Resource
    Mechanical and biochemical analyses of tibial compartment fascia in chronic compartment syndrome (1994)
    Springer
    Annals of biomedical engineering 22 (1994), S. 272-279 
    Details
    ISSN: 1573-9686
    Keywords: Chronic compartment syndrome ; Fascia ; Elasticity ; Viscoelasticity ; Collagen ; Collagen crosslinking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Increases in compartment pressure associated with chronic compartment syndrome (CCS) may be due to changes in the mechanical properties and/or thickness of fascia (4,22). To explore this possibility, we compared the mechanical and biochemical characteristics (stiffness, thickness, time-dependent response, collagen content, and collagen crosslinking) of fascia from patients with symptomatic anterior compartment syndrome to fascia from adjacent collateral compartments. We tested 43 specimens harvested from 20 individuals during surgical fasciectomy. Properties of normal (lateral)-compartment (NC) and pathological (anterior)-compartment (PC) fascia were mechanically tested in the axial and transverse directions forming four groups. An external control group (EX) of six specimens of anterior and lateral-compartment fascia harvested from amputated legs was also included in the study. PC fascia was found to be thicker and structurally stiffer (elastic modulus times thickness) in the axial direction than was NC fascia (p≤0.05). No significant differences were found between NC and PC time-dependent response, although significant differences between percent relaxation in the pooled axial and transverse direction specimens were observed. No differences were found in the collagen content, as measured by hydroxyproline (Hyp) concentration, between NC and PC fascia. PC fascia was found to have less collagen crosslinking by hydroxylyslpyridinoline (HP) concentration. In conclusion, although this study does not elucidate etiological factors in CCS, the changes found in PC fascia suggest that fascial mechanical properties contribute to the pathology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02368234
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  • 3
    Electronic Resource
    Electronic Resource
    Relationships between stem structure and bending strength in Pinus radiata seedlings (1993)
    Springer
    Trees 7 (1993), S. 86-91 
    Details
    ISSN: 1432-2285
    Keywords: Pinus radiata ; Stem deformation ; Nitrogen ; Stem form ; Elasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Seedlings from nine families of Pinus radiata were grown in a glasshouse under conditions of high and low nitrate nitrogen availability to investigate effects on anatomical and strength characteristics of stems. Families were classified into groups dependent upon their previously determined susceptibility to stem deformation prevalent in plantations established on fertile ex-pasture. Nitrogen treatments significantly affected seedling form in terms of both branch production and stem slenderness. The high N treatment resulted in shorter seedlings, a proportion of which were obviously stunted. Stem strength of seedlings, physically supported throughout the experiment, was assessed as stem lean at harvest as well as the bending strength of the fresh stem at 50% stem height. These two variables were found not to be correlated. Stem lean at harvest was greatest in families known to be susceptible to stem deformation. These families produced stems that were also more slender than families of low susceptibility. Increased stem lean was associated mostly with increased stem slenderness while elasticity was more influenced by pith diameter, stem density and wood radius.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225474
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  • 4
    Electronic Resource
    Electronic Resource
    Strength and structure of stems from fast grown Pinus radiata (1993)
    Springer
    Trees 7 (1993), S. 131-136 
    Details
    ISSN: 1432-2285
    Keywords: Pinus radiata ; Stem strength ; Elasticity ; Lignin ; Microfibril angle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Segments of living stems from 2-year-old, fast growing Pinus radiata, established on a fertile ex-pasture, were examined in terms of their bending strength parallel to the grain. Stem anatomical and structural variables were examined to identify variables that could explain variation in bending strength. Half of the seedlings were physically supported to minimise the confounding effects of compression wood production in response to environmental stresses. Differences between seedlings and cuttings were examined. Variation in microfibril angle and lignin content was sufficient to account for 81% of the variation in bending strength. A positive correlation between both of these variables and elasticity was evident. Few differences were found to be caused by the support treatment or between seedlings and cuttings. The support treatment resulted in significantly fewer branches in the top most whorl, while cuttings had less branches in this whorl than seedlings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00199612
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  • 5
    Electronic Resource
    Electronic Resource
    Accuracy in measurements and the temperature and volume dependence of thermoelastic parameters (1993)
    Springer
    Pure and applied geophysics 141 (1993), S. 327-339 
    Details
    ISSN: 1420-9136
    Keywords: Elasticity ; thermoelasticity ; piston-cylinder ; rectangular parallepiped resonance ; MgO ; NaCl ; Anderson-Grüneisen parameter ; equation of state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract To obtain the temperatureT and volumeV (or pressureP) dependence of the Anderson-Grüneisen parameter δ T , measurements with high sensitivity are required. We show two examples:P, V, T measurements of NaCl done with the piston cylinder and elasticity measurements of MgO using a resonance method. In both cases, the sensitivity of the measurements leads to results that provide information about δ T (η,T), where η≡V/V 0 andV 0 is the volume at zero pressure. We demonstrate that determination of δ T leads to understanding of the volume and temperature dependence ofq=(∂ ln γ/∂ lnV) T over a broadV, T range, where γ is the Grüneisen ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00998334
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  • 6
    Electronic Resource
    Electronic Resource
    Thigmonasticity of thistle staminal filaments (1993)
    Springer
    Planta 190 (1993), S. 58-64 
    Details
    ISSN: 1432-2048
    Keywords: Cell wall ; Cirsium (cell wall) ; Cuticle ; Elasticity ; Thigmonasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Investigations of the longitudinal distribution of the extensibility of staminal filaments of the common thistle (Cirsium horridulum Michx.) showed that the base of the filaments (attachment to corolla) is almost twice as elastic as the apical portion (next to anthers). Boiling leads to a more uniform distribution of extensibility. Using a stress-strain analyzer we investigated the elastic properties of fresh, water-boiled, partially hydrolyzed (acid-boiled), and dehydrated filaments. Stress-strain curves of sinusoidally stretched sets of filaments revealed complex, non-linear behavior with an average modulus of elasticity of 5 MPa·m−2. The phase angle varied from approximately 18 degrees for 0.01-Hz deformations to 84 degrees at 2 Hz, indicating strong viscoelastic components. The viscoelasticity of the filaments indicates that the cell walls have a high ratio of pectin to cellulose. Boiling does not affect Young's modulus, but dehydration does. The technique of applying sinusoidal loads and the analysis of the stress-strain curves proves useful for the assessment of mechanical properties of cell walls, especially for non-growing or contractile tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195675
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  • 7
    Electronic Resource
    Electronic Resource
    Elasticity of the crystal-like, amorphous solid-like, and liquid-like structures in deionized suspensions of colloidal silica spheres (1993)
    Springer
    Colloid & polymer science 271 (1993), S. 873-883 
    Details
    ISSN: 1435-1536
    Keywords: Elasticity ; suspension structure ; colloidal crystals ; colloidal silica ; reflection spectroscopy ; viscometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Elastic moduli (G) of deionized suspensions of colloidal silica spheres (diameters=45–192 nm; standard deviations of sphere size divided by the mean diameter=0.05–0.21; surface charge densities=0.33–0.94 μC/cm2; volume fractions of sphere (ϕ)=0.019–0.21) have been determined by the reflection spectrum measurements in a sedimentation equilibrium and the rotatory viscometry. TheG-values are 56–460 Pa (ϕ=0.019–0.051), 330–890 Pa (0.06–0.09), and 100 Pa (0.025) for the crystal-like, amorphous solid-like, and liquid-like structures, respectively. TheG-values seem to be in the order amorphous solid-like 〉 crystal-like 〉 liquid-like at the same sphere concentration. The suspension structures and their elastic moduli are highly influenced by the sizes and their monodispersities of the spheres. These results support that the electrostatic intersphere repulsion and the long Debye-screening length around the spheres are important for the appearance of the suspension structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00652770
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  • 8
    Electronic Resource
    Electronic Resource
    Difference equations approach to the analysis of layered systems (1992)
    Springer
    Meccanica 26 (1992), S. 195-209 
    Details
    ISSN: 1572-9648
    Keywords: Elasticity ; layered systems ; difference equations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario Nell' articolo vengono esaminate, sulla base di equazioni alle differenze, strutture di tipo ‘catena’. Si mettono in rilievo i vantaggi di un tale approccio. Per i sistemi complessi sono state ottenute equazioni alle differenze sia in termini di trazioni che spostamenti. Vengono stabiliti legami con altri metodi. Si fa un'analisi dettagliata del caso in cui la soluzione per un singolo strato ě rappresentata sotto la forma della serie di Fourier (integrale). Vengono esposti pure risultati pratici.
    Notes: Abstract The analysis of chain-like structures is tackled on the basis of difference equations. The advantages of such an approach are outlined. Difference equations for layered systems are derived both in terms of tractions and displacements. Interconnections with other methods are stated. Detailed analysis is given for the case when solution for a single layer is presented by Fourier series (integrals). Practical conclusions are driven at.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00430937
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  • 9
    Electronic Resource
    Electronic Resource
    After-Effects of Electrolytically diffused hydrogen in the second-order elastic coefficient of poynting’s effect in nickel and steel (1992)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 14 (1992), S. 1105-1113 
    Details
    ISSN: 0392-6737
    Keywords: Elasticity ; elastic constants ; vibration ; Diffusion ; migration and displacement of impurities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary If hydrogen is diffused electrolytically in a metal, it subsequently escapes out if the metal is left to itself. However this hydrogen-treated metal does not totally regain the original magnitudes of its various physical properties,e. g., thermo e.m.f., electrical resistivity, elastic modulii etc. This effect has also been observed in the second-order elastic effect (the Poynting effect) in nickel and two varieties of steel. Measurements were carried out first before hydrogen diffusion. The samples were electrolytically diffused with hydrogen and the left to themselves for a few days and the measurements were repeated. The changed values of the coefficient of Poynting effect are discussed in terms of the dislocations created by in-and out-going hydrogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02456763
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  • 10
    Electronic Resource
    Electronic Resource
    The elastic deformability of closed multilayered membranes is the same as that of a bilayer membrane (1992)
    Springer
    European biophysics journal 21 (1992), S. 251-255 
    Details
    ISSN: 1432-1017
    Keywords: Multilayered membranes ; Elasticity ; Elastic constants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The elastic behavior of closed multilayered membranes is analyzed with the assumption that the constituent layers are in close contact but are unconnected in the sense that they are free to slide by one another. The system exhibits three independent elastic deformation modes for any number of the constituent layers equal to or larger than two. These are the area expansivity of the membrane neutral surface, and the local and non-local membrane bending. The corresponding elastic moduli are expressed in terms of the elastic moduli of the constituent layers, their areas, and distances between their neutral surfaces. Closed multilayered membranes only differ from a closed bilayer membrane in that for any of their shapes some of the constituent layers are expanded and some compressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185119
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  • 11
    Electronic Resource
    Electronic Resource
    The rigid inclusion with highest penetration (1991)
    Springer
    Meccanica 26 (1991), S. 149-153 
    Details
    ISSN: 1572-9648
    Keywords: Elasticity ; shape optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario Un'inclusione clinidrica rigida con sezione trascersale di area limitata e forma variabile è immersa in un mezzo elastico infinito. Avendo supposto che la sezione possegga un asse di simmetria e che sia spinta nel mezzo da una forza agent secondo tale asse, si pone il problema di trovare il profilo della sezione per cui è massima la penetrazione. Una risposta si può dare solo per due classi particolari di domini in elasticità piana.
    Notes: Abstract A cylindrical bounded rigid inclusion with cross section of bounded area and variable shape is embedded in an infinite elastic medium. Assuming that the cross section possesses an axis of symmetry and that it is pushed into the medium by a force acting in the direction of this axis, the question arises of finding the section's profile for which penetration is highest. A solution is found only for two particular classes of domains in plane elasticity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429882
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  • 12
    Electronic Resource
    Electronic Resource
    Thigmonasticity of thistle staminal filaments (1991)
    Springer
    Protoplasma 163 (1991), S. 174-180 
    Details
    ISSN: 1615-6102
    Keywords: Asteraceae ; Thigmonasticity ; Cuticle ; Elasticity ; Extensibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Touching stimulates thistle (Cirsium horridulum Michx.) staminal filaments to rapidly shorten to approximately 70% of their original length. The filaments subsequently re-elongate and regain contractibility within 10min. This thigmonastic movement can be repeated at least 10 times in detached flowers. Filament length is reduced by bathing in 1 M sorbitol, indicating that length change depends on variation in turgor pressure, as is also indicated by plasmolysis observed in contracted filaments. Contraction also depends upon elastic properties of the cuticle. These properties of the cuticle are resistant to boiling in water, chloroform or acid, and treatment with proteases, protein denaturants, sulfatases, and many cell wall degrading enzymes, but are sensitive to cutinase, β-glucuronidase, and boiling in 1 M NaOH. Analysis of carbohydrates from flowers boiled in 1 N NaOH showed that most galacturonic acid residues were extracted from filaments but not from petals (which are inelastic). The filament galacturonic acid residues may form a part of the cuticular contractile mechanism, and/or they may facilitate the bending of the vascular and cortical cells that occurs during contraction. Our results indicate that the elasticity of the stretched cuticle provides the force for the contraction of the filaments and the build-up of turgor causes re-elongation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323341
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  • 13
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    Finite Elemente Simulation von Fluidbewegungen in einem deformierbaren poroelastischen Medium mit druckabhängiger Permeabilität (1990)
    Technische Universität Clausthal-Zellerfeld, Math.-Naturwiss. Fakultät
    In:  Dissertation, Clausthal-Zellerfeld, Technische Universität Clausthal-Zellerfeld, Math.-Naturwiss. Fakultät, vol. 10, no. GL-TR-89-0259, pp. 277-280, (ISBN 0 08 042822 3)
    Details
    Publication Date: 1990
    Keywords: Rock mechanics ; Fracture ; Elasticity ; Finite Element Method ; Fluids ; salt ; diapir
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    BIBLIOGRAPHY SEISMOLOGY
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