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Breaking Strength (breaking + strength)
Selected AbstractsEffects of egg weight on egg quality characteristicsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2009Ahmet, ekero Abstract BACKGROUND: The experiment was carried out with total of 270 eggs, which were collected from a brown-egg layer strain of Lohmann hens reared in a cage system. Collected eggs were categorized according to weight and classified as medium, large, extra-large or jumbo. The purpose of the study was to determine the effect of egg weight on egg quality characteristics. RESULTS: The darkest shell color scales were noted in jumbo eggs. The redness of egg shell color in the medium egg was significantly lower than that of the other egg sizes (P < 0.05). Egg shell thickness (P < 0.05) was highest in medium egg (0.400 mm) and lowest in extra-large egg (0.382 mm). Albumen height (AH) was significantly affected by egg weight (EW) (P < 0.01). Yolk height (YH) and yolk index (YI) increased with egg size. Breaking strength was highest in the medium-weight egg. There were significant positive correlations between EW and AH, EW and YH, EW and YI, EW and yol color, EW and redness (a), but EW had significant negative correlations with ST in overall eggs. CONCLUSION: The darkest shell color (L - a - b) was noted in the jumbo egg. Albumen height and yolk height increased with egg weight. Increase in egg weight caused darkness in the yolk color scale. Copyright © 2008 Society of Chemical Industry [source] Novel Polysaccharide-derived hydrogel prevents perineural adhesions in a rat model of sciatic nerve adhesionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2010Michiro Yamamoto Abstract We investigated the effects of a novel carboxymethylcellulose (CMC)-derived hydrogel, in which phosphatidylethanolamine (PE) was introduced into the carboxyl groups of CMC, for preventing perineural adhesion after extensive internal neurolysis of rat sciatic nerve. Sciatic nerves were randomly assigned to one of the following groups: the Control group, operated but no treatment; the HA group, operated and treated with 1% hyaluronan; the CMC,PE(L) group, operated and treated with low-viscosity CMC,PE hydrogel; and the CMC,PE(H) group, operated and treated with high-viscosity CMC,PE hydrogel. Perineural adhesions were evaluated at 6 weeks. Nerves were also subjected to biomechanical testing to assess ultimate breaking strength. Electrophysiological and wet muscle weight measurements were performed. Breaking strengths were significantly lower for the CMC,PE(L) group than for the Control and HA groups. Latency was significantly longer for the Control group than for the CMC,PE(L) group at 20 days. The mean percentage of wet muscle weight to body weight was significantly lower for the Control group than for the CMC,PE(L) group at 6 weeks. Low-viscosity CMC,PE hydrogel appears to prevent perineural adhesions and allow early restoration of nerve function. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:284,288, 2010 [source] A damage mechanics model for power-law creep and earthquake aftershock and foreshock sequencesGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Ian G. Main It is common practice to refer to three independent stages of creep under static loading conditions in the laboratory: namely transient, steady-state, and accelerating. Here we suggest a simple damage mechanics model for the apparently trimodal behaviour of the strain and event rate dependence, by invoking two local mechanisms of positive and negative feedback applied to constitutive rules for time-dependent subcritical crack growth. In both phases, the individual constitutive rule for measured strain , takes the form ,(t),=,,0,[1,+,t/m,]m, where , is the ratio of initial crack length to rupture velocity. For a local hardening mechanism (negative feedback), we find that transient creep dominates, with 0,<,m,<,1. Crack growth in this stage is stable and decelerating. For a local softening mechanism (positive feedback), m,<,0, and crack growth is unstable and accelerating. In this case a quasi-static instability criterion , , , can be defined at a finite failure time, resulting in the localization of damage and the formation of a throughgoing fracture. In the hybrid model, transient creep dominates in the early stages of damage and accelerating creep in the latter stages. At intermediate times the linear superposition of the two mechanisms spontaneously produces an apparent steady-state phase of relatively constant strain rate, with a power-law rheology, as observed in laboratory creep test data. The predicted acoustic emission event rates in the transient and accelerating phases are identical to the modified Omori laws for aftershocks and foreshocks, respectively, and provide a physical meaning for the empirical constants measured. At intermediate times, the event rate tends to a relatively constant background rate. The requirement for a finite event rate at the time of the main shock can be satisfied by modifying the instability criterion to having a finite crack velocity at the dynamic failure time, dx/dt , VR,, where VR is the dynamic rupture velocity. The same hybrid model can be modified to account for dynamic loading (constant stress rate) boundary conditions, and predicts the observed loading rate dependence of the breaking strength. The resulting scaling exponents imply systematically more non-linear behaviour for dynamic loading. [source] Multibranched Junctions of Carbon Nanotubes via Cobalt ParticlesADVANCED MATERIALS, Issue 44 2009Julio A. Rodríguez-Manzo Junctions between different carbon nanotubes are created using cobalt particles as central nodes (see image). The process involves high temperature and electron irradiation of areas where a metal particle is located at the overlapping region of two nanotubes. In situ transmission electron microscopy measurements show that the junctions are electrically conductive and mechanically robust. A high breaking strength of 1,5,GPa is found for the junctions. [source] Structure and properties of regenerated Antheraea pernyi silk fibroin filamentsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Baoqi Zuo Abstract Degummed Antheraeapernyi silk fibroin (APSF) fibers were dissolved in a lithium thiocyanate solution that was dialyzed against distilled water for 3 days. Solution-cast APSF films were dissolved in hexafluoroisopropanol to prepare a spinning solution. Wet spinning was employed to prepare APSF filaments. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, solid-state 13C cross-polarization/magic angle spinning nuclear magnetic resonance, and differential scanning calorimetry were employed to study the regenerated APSF filaments. The results showed a uniform distribution of molecular weights, and the largest one may have been greater than 200 kDa. The regenerated filaments contained ,-sheet, ,-helix, and random-coil conformations, and their breaking strength was 52.20% of the breaking strength of the native fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Electrospun polylactide/silk fibroin,gelatin composite tubular scaffolds for small-diameter tissue engineering blood vesselsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Shudong Wang Abstract Many synthetic scaffolds have been used as vascular substitutes for clinical use. However, many of these scaffolds may not show suitable properties when they are exposed to physiologic vascular environments, and they may fail eventually because of some unexpected conditions. Electrospinning technology offers the potential for controlling the composition, structure, and mechanical properties of scaffolds. In this study, a tubular scaffold (inner diameter = 4.5 mm) composed of a polylactide (PLA) fiber outside layer and a silk fibroin (SF),gelatin fiber inner layer (PLA/SF,gelatin) was fabricated by electrospinning. The morphological, biomechanical, and biological properties of the composite scaffold were examined. The PLA/SF,gelatin composite tubular scaffold possessed a porous structure; the porosity of the scaffold reached 82 ± 2%. The composite scaffold achieved the appropriate breaking strength (1.28 ± 0.21 MPa) and adequate pliability (elasticity up to 41.11 ± 2.17% strain) and possessed a fine suture retention strength (1.07 ± 0.07 N). The burst pressure of the composite scaffold was 111.4 ± 2.6 kPa, which was much higher than the native vessels. A mitochondrial metabolic assay and scanning electron microscopy observations indicated that both 3T3 mouse fibroblasts and human umbilical vein endothelial cells grew and proliferated well on the composite scaffold in vitro after they were cultured for some days. The PLA/SF,gelatin composite tubular scaffolds presented appropriate characteristics to be considered as candidate scaffolds for blood vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Influence of different functionalized multiwall carbon nanotubes on the mechanical properties of poly(ethylene terephthalate) fibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Liming Shen Abstract Master batches with four different kinds of functionalized multiwall carbon nanotubes (MWCTs) were prepared through the mixing of MWCTs with poly(ethylene terephthalate) (PET) (0.01 : 0.99 w/w) in trifluoroacetic acid/dichloromethane mixed solvents (0.7 : 0.3 v/v) followed by the removal of the solvents in the mixture by flocculation. The results of scanning electron microscopy showed that a good dispersion of MWCTs in PET was achieved. The reinforced fibers were fabricated by the melt spinning of PET chips with small amounts of the master batch and then further postdrawing. The optimal spinning conditions for the reinforcement of fibers were a 0.6-mm spinneret hole and a 250 m/min wind-up speed. Among the four master batches, the fibers obtained from PET/master batch B made by acid-treatment had the highest enhancement of mechanical properties. For a 0.02 wt % loading of acid-treated MWCT, the breaking strength of the PET/master batch B composite fibers increased by 36.9% (from 4.45 to 6.09 cN/dtex), and the initial modulus increased by 41.2% (from 80.7 to 113.9 cN/dtex). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Tendon surface modification by chemically modified HA coating after flexor digitorum profundus tendon repairJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2004Chao Yang Abstract Carbodiimide derivatized HA (cd-HA) is less soluble in water than normal HA, and therefore has an increased tissue residence time. The purpose of this study was to study the effect of cd-HA gel on gliding and repair integrity during simulated repetitive motion of a repaired tendon in vitro. A total of 36 flexor digitorum profundus (FDP) tendons from six adult mongrel dogs were used and divided into three groups of control, simple HA, and cd-HA. The gliding resistance between the FDP and the proximal pulley, FDS, and bone was measured before laceration and after modified Kessler technique repair at 1, 5, 10, 50, 100, 200, 300, 400, and 500 cycles. After gliding testing, failure load, tendon stiffness, and resistance to gap formation were measured. The results showed from the first cycle to the 10th cycle, there were no significant differences in gliding resistance between the three testing groups (p > 0.05). From the 50th cycle onwards, the friction was significantly lower in the cd-HA gel group than in the control group (p < 0.05). Neither breaking strength, nor tendon stiffness, nor resistance to gap formation of the repairs were significantly different between the three groups (p > 0.05). © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 15,20, 2004 [source] The Structural and Hormonal Basis of Sex Differences in Peak Appendicular Bone Strength in Rats,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2003Bom-Taeck Kim Abstract To identify the structural and hormonal basis for the lower incidence of fractures in males than females, sex differences in femoral mid-shaft geometry and breaking strength were studied in growth hormone (GH)-replete and -deficient male and female rats. Sexual dimorphism appeared during growth. Cortical thickening occurred almost entirely by acquisition of bone on the outer (periosteal) surface in males and mainly on the inner (endocortical) surface in females. By 8 months of age, males had 22% greater bone width and 33% greater breaking strength than females. Gonadectomy (Gx) at 6 weeks reduced sex differences in bone width to 7% and strength to 21% by halving periosteal bone formation in males and doubling it in females. Gx had no net effect on the endocortical surface in males but abolished endocortical bone acquisition in females. GH deficiency halved periosteal bone formation and had no net effect on the endocortical surface in males, but abolished bone acquisition on both surfaces in females, leaving males with 17% greater bone width and 44% greater breaking strength than females. Sex hormone deficiency produces greater bone fragility in males than females by removing a stimulator of periosteal growth in males and removing an inhibitor of periosteal growth in females. GH deficiency produces less bone fragility in males than females because males retain androgen-dependent periosteal bone formation while bone acquisition on both surfaces is abolished in females. Thus, periosteal growth is independently and additively stimulated by androgens and GH in males, inhibited by estrogen, and stimulated by GH in females. The hormonal regulation of bone surfaces establishes the amount and spatial distribution of bone and so the sexual dimorphism in its strength. [source] Novel Polysaccharide-derived hydrogel prevents perineural adhesions in a rat model of sciatic nerve adhesionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2010Michiro Yamamoto Abstract We investigated the effects of a novel carboxymethylcellulose (CMC)-derived hydrogel, in which phosphatidylethanolamine (PE) was introduced into the carboxyl groups of CMC, for preventing perineural adhesion after extensive internal neurolysis of rat sciatic nerve. Sciatic nerves were randomly assigned to one of the following groups: the Control group, operated but no treatment; the HA group, operated and treated with 1% hyaluronan; the CMC,PE(L) group, operated and treated with low-viscosity CMC,PE hydrogel; and the CMC,PE(H) group, operated and treated with high-viscosity CMC,PE hydrogel. Perineural adhesions were evaluated at 6 weeks. Nerves were also subjected to biomechanical testing to assess ultimate breaking strength. Electrophysiological and wet muscle weight measurements were performed. Breaking strengths were significantly lower for the CMC,PE(L) group than for the Control and HA groups. Latency was significantly longer for the Control group than for the CMC,PE(L) group at 20 days. The mean percentage of wet muscle weight to body weight was significantly lower for the Control group than for the CMC,PE(L) group at 6 weeks. Low-viscosity CMC,PE hydrogel appears to prevent perineural adhesions and allow early restoration of nerve function. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:284,288, 2010 [source] Wound healing properties of Hylocereus undatus on diabetic ratsPHYTOTHERAPY RESEARCH, Issue 8 2005R. M. Perez G. Abstract Aqueous extracts of leaves, rind, fruit pulp and flowers of Hylocereus undatus were studied for their wound healing properties. Wound healing effects were studied on incision (skin breaking strength), excision (percent wound contraction) and the nature of wound granulation tissues, which were removed on day 7 and the collagen, hexosamine, total proteins and DNA contents were determined, in addition to the rates of wound contraction and the period of epithelialization. In streptozotocin diabetic rats, where healing is delayed, topical applications of H. undatus produced increases in hydroxyproline, tensile strength, total proteins, DNA collagen content and better epithelization thereby facilitating healing. H. undatus had no hypoglycemic activity. Copyright © 2005 John Wiley & Sons, Ltd. [source] Polymorphisms in eggshell organic matrix genes are associated with eggshell quality measurements in pedigree Rhode Island Red hensANIMAL GENETICS, Issue 1 2009I. C. Dunn Summary Novel and traditional eggshell quality measurements were made from up to 2000 commercial pedigree hens for a candidate gene association analysis with organic eggshell matrix genes: ovocleidin-116, osteopontin (SPP1), ovocalyxin-32 (RARRES1), ovotransferrin (LTF), ovalbumin and ovocalyxin-36, as well as key genes in the maintenance and function of the shell gland [estrogen receptor (ESR1) and carbonic anhydrase II (CAII)]. Associations were found for (i) ovalbumin with breaking strength and shell thickness; (ii) ovocleidin-116 with elastic modulus, shell thickness and egg shape; (iii) RARRES1 with mammillary layer thickness; (iv) ESR1 with dynamic stiffness; (v) SPP1 with fracture toughness and (vi) CAII with egg shape. The marker effects are as large as 17% of trait standard deviations and could be used to improve eggshell quality. [source] Influence of Sulfonation on the Properties of Expanded Extrudates Containing 32% Whey ProteinJOURNAL OF FOOD SCIENCE, Issue 2 2006David P. Taylor ABSTRACT Whey protein concentrate (WPC) was treated with sodium sulfite to achieve 4 levels of disulfide bond sulfonation (0%, 31%, 54%, and 71% mole/mole). The WPCs were blended with cornstarch to a 32% (weigh/weight) protein content and extruded into an expanded product. Extrudates were collected at 160 °C and 170 °C and analyzed for physical (air cell diameter, expansion ratio, breaking strength, and density) and chemical (water adsorption index [WAI], water solubility index, moisture content, soluble protein, and carbohydrates) properties. The control and 54% sulfonated samples had larger expansion ratios and air cell diameters and smaller densities and breaking strengths than the 31% and 71% samples. Expansion increased at 170 °C in the sulfonated samples. The WAI was influenced by both sulfonation and temperature, whereas the other chemical properties (except moisture content) were influenced only by sulfonation level. Soluble protein and carbohydrate were highest in the control and 54% samples. The anomalous behavior of the 54% sample may have been the result of significant structural and functional changes of ,-lactalbumin that are predicted to occur at approximately 50% sulfonation. Many functional properties of the WPCs were measured and were significantly correlated to the extrudate properties, particularly those related to protein unfolding and flexibility The increased ability for the proteins to become unfolded during extrusion may have promoted protein-starch interactions, which led to decreases in expansion and overall quality Disulfide bond content did influence the chemical and physical properties of an extruded-expanded whey protein products. [source] Monitoring processes with data censored owing to competing risks by using exponentially weighted moving average control chartsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 3 2001Stefan H. Steiner In industry, process monitoring is widely employed to detect process changes rapidly. However, in some industrial applications observations are censored. For example, when testing breaking strengths and failure times often a limited stress test is performed. With censored observations, a direct application of traditional monitoring procedures is not appropriate. When the censoring occurs due to competing risks, we propose a control chart based on conditional expected values to detect changes in the mean strength. To protect against possible confounding caused by changes in the mean of the censoring mechanism we also suggest a similar chart to detect changes in the mean censoring level. We provide an example of monitoring bond strength to illustrate the application of this methodology. [source] | |||||||||||||||||||