Stretch Sensor Device

DEFF Research Database (Denmark)

2013-01-01

The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

The study of microstrip electromagnetic properties and method of measuring {epsilon} sub r

Energy Technology Data Exchange (ETDEWEB)

Wan Ali, Wan Khairuddin [Universiti Teknologi Malaysia, Skudai, Johor Bahru (Malaysia)

1994-12-31

Equivalent circuits have been derived for microstrip ring resonator using transmission lines theory. From the analysis, two equations were derived. The first equation relates all the parameters of a ring into a single equation. This equation has been used in the design process to determine the ring dimensions. The second equation was used to calculate S sub 21 and was given as a function of relative permittivity, {epsilon} sub r, and angular frequency, {omega}. A procedure has been suggested on how these equations can be used to determine the value of {epsilon} sub r for an unknown substrate. The calculations using the data from experiment were compared with the values given by the manufacturer and was found to be within 8% different.

Multiple groups of endogenous epsilon-like retroviruses conserved across primates.

Science.gov (United States)

Brown, Katherine; Emes, Richard D; Tarlinton, Rachael E

2014-11-01

Several types of cancer in fish are caused by retroviruses, including those responsible for major outbreaks of disease, such as walleye dermal sarcoma virus and salmon swim bladder sarcoma virus. These viruses form a phylogenetic group often described as the epsilonretrovirus genus. Epsilon-like retroviruses have become endogenous retroviruses (ERVs) on several occasions, integrating into germ line cells to become part of the host genome, and sections of fish and amphibian genomes are derived from epsilon-like retroviruses. However, epsilon-like ERVs have been identified in very few mammals. We have developed a pipeline to screen full genomes for ERVs, and using this pipeline, we have located over 800 endogenous epsilon-like ERV fragments in primate genomes. Genomes from 32 species of mammals and birds were screened, and epsilon-like ERV fragments were found in all primate and tree shrew genomes but no others. These viruses appear to have entered the genome of a common ancestor of Old and New World monkeys between 42 million and 65 million years ago. Based on these results, there is an ancient evolutionary relationship between epsilon-like retroviruses and primates. Clearly, these viruses had the potential to infect the ancestors of primates and were at some point a common pathogen in these hosts. Therefore, this result raises questions about the potential of epsilonretroviruses to infect humans and other primates and about the evolutionary history of these retroviruses. Epsilonretroviruses are a group of retroviruses that cause several important diseases in fish. Retroviruses have the ability to become a permanent part of the DNA of their host by entering the germ line as endogenous retroviruses (ERVs), where they lose their infectivity over time but can be recognized as retroviruses for millions of years. Very few mammals are known to have epsilon-like ERVs; however, we have identified over 800 fragments of endogenous epsilon-like ERVs in the genomes of all major

Apolipoprotein E-epsilon 4 frequency in affective disorder

DEFF Research Database (Denmark)

Kessing, L V; Jørgensen, O S

1999-01-01

-Bråne-Steen Dementia Rating Scale, and the Global Deterioration Scale. RESULTS: The frequency of APOE-epsilon 4 allele was approximately the same in unipolar patients (.189) and in bipolar patients (.167). Although patients showed more cognitive impairment than controls, no significant overall difference was found...... was found with gender, age at onset, the number of affective episodes, the presence of psychotic features, or the prevalence of familial affective disorder. CONCLUSIONS: It seems that cognitive impairment in affective disorder can be attributed to pathways other than the APOE genotype.......BACKGROUND: The epsilon 4 allele of apolipoprotein E (APOE) as well as affective disorder have been found to be associated with Alzheimer's disease, but it is unclear whether cognitive impairment in affective disorder or subtypes of affective disorder is mediated by the epsilon 4 allele of APOE...

QED in d=3 from the epsilon-expansion.

CERN Multimedia

CERN. Geneva

2015-01-01

In my talk, based on the recent work 1508.06278, I will consider the Renormalization Group flow of Quantum Electrodynamics in d=3 coupled to N_f flavors of fermions. For N_f smaller than a critical value N_f^c, chiral symmetry breaking is believed to take place. For N_f > N_f^c, the theory flows to an interacting fixed point that can be studied in the epsilon-expansion, using the fixed point in d=4-2\\epsilon. I will discuss the computation of the anomalous dimensions of fermion bilinears and quadrilinear operators, as well as some more conceptual aspects concerning the enhancement of global symmetries in d=3. For small N_f, a quadrilinear operator can become relevant in the IR and destabilize the fixed point. Therefore, the epsilon-expansion can be used to estimate N_f^c.

Stretching

Science.gov (United States)

... after a workout. Stretching still can be a beneficial activity after you have sufficiently warmed up. The ... light aerobic activity and stretching. If you're running at a quick pace, you can slow down ...

Advanced k-epsilon modeling of heat transfer

Science.gov (United States)

Kwon, Okey; Ames, Forrest E.

1995-01-01

This report describes two approaches to low Reynolds-number k-epsilon turbulence modeling which formulate the eddy viscosity on the wall-normal component of turbulence and a length scale. The wall-normal component of turbulence is computed via integration of the energy spectrum based on the local dissipation rate and is bounded by the isotropic condition. The models account for the anisotropy of the dissipation and the reduced mixing length due to the high strain rates present in the near-wall region. The turbulent kinetic energy and its dissipation rate were computed from the k and epsilon transport equations of Durbin. The models were tested for a wide range of turbulent flows and proved to be superior to other k-epsilon models, especially for nonequilibrium anisotropic flows. For the prediction of airfoil heat transfer, the models included a set of empirical correlations for predicting laminar-turbulent transition and laminar heat transfer augmentation due to the presence of freestream turbulence. The predictions of surface heat transfer were generally satisfactory.

Spectrophotometry of Epsilon Aur, 3295-8880 A

Science.gov (United States)

Lockwood, G. W.; Thompson, D. T.; Lutz, B. L.; Sowell, J.

1985-01-01

Spectrophotometric scans were obtained at 8 A resolution from 3295 to 8880 A on twenty nights before, during, and after the recent eclipse of epsilon Aurigae, beginning with a pre-eclipse observation on 5 March 1982 U.T. The observations were reduced to absolute flux using the standard stars 109 Vir or xi(2) Ceti. The data confirm that the eclipse is essentially gray over the entire visible spectrum, as others have noted from broadband photometry. High resolution echellograms (450 to 6700 A) made through mid-eclipse and the scans show changes in the equivalent widths of H alpha, Na D, and O I as large as a factor of two.

Association of apolipoprotein E allele {epsilon}4 with late-onset sporadic Alzheimer`s disease

Energy Technology Data Exchange (ETDEWEB)

Lucotte, G.; David, F.; Berriche, S. [Regional Center of Neurogenetics, Reims (France)] [and others

1994-09-15

Apolipoprotein E, type {epsilon}4 allele (ApoE {epsilon}4), is associated with late-onset sporadic Alzheimer`s disease (AD) in French patients. The association is highly significant (0.45 AD versus 0.12 controls for {epsilon}4 allele frequencies). These data support the involvement of ApoE {epsilon}4 allele as a very important risk factor for the clinical expression of AD. 22 refs., 1 fig., 3 tabs.

Iron Carbides in Fischer–Tropsch Synthesis: Theoretical and Experimental Understanding in Epsilon-Iron Carbide Phase Assignment

International Nuclear Information System (INIS)

Liu, Xing-Wu; Cao, Zhi; Zhao, Shu; Gao, Rui

2017-01-01

As active phases in low-temperature Fischer–Tropsch synthesis for liquid fuel production, epsilon iron carbides are critically important industrial materials. However, the precise atomic structure of epsilon iron carbides remains unclear, leading to a half-century of debate on the phase assignment of the ε-Fe 2 C and ε’-Fe 2.2 C. Here, we resolve this decades-long question by a combining theoretical and experimental investigation to assign the phases unambiguously. First, we have investigated the equilibrium structures and thermal stabilities of ε-Fe x C, (x = 1, 2, 2.2, 3, 4, 6, 8) by first-principles calculations. We have also acquired X-ray diffraction patterns and Mössbauer spectra for these epsilon iron carbides, and compared them with the simulated results. These analyses indicate that the unit cell of ε-Fe 2 C contains only one type of chemical environment for Fe atoms, while ε’-Fe 2.2 C has six sets of chemically distinct Fe atoms.

epsilon-N-trimethyllysine availability regulates the rate of carnitine biosynthesis in the growing rat

International Nuclear Information System (INIS)

Rebouche, C.J.; Lehman, L.J.; Olson, L.

1986-01-01

Rates of carnitine biosynthesis in mammals depend on the availability of substrates and the activity of enzymes subserving the pathway. This study was undertaken to test the hypothesis that the availability of epsilon-N-trimethyllysine is rate-limiting for synthesis of carnitine in the growing rat and to evaluate diet as a source of this precursor for carnitine biosynthesis. Rats apparently absorbed greater than 90% of a tracer dose of [methyl- 3 H]epsilon-N-trimethyllysine, and approximately 30% of that was incorporated into tissues as [ 3 H]carnitine. Rats given oral supplements of epsilon-N-trimethyllysine (0.5-20 mg/d), but no dietary carnitine, excreted more carnitine than control animals receiving no dietary epsilon-N-trimethyllysine or carnitine. Rates of carnitine excretion increased in a dose-dependent manner. Tissue and serum levels of carnitine also increased with dietary epsilon-N-trimethyllysine supplementation. There was no evidence that the capacity for carnitine biosynthesis was saturated even at the highest level of oral epsilon-N-trimethyllysine supplementation. Common dietary proteins (casein, soy protein and wheat gluten) were found to be poor sources of epsilon-N-trimethyllysine for carnitine biosynthesis. The results of this study indicate that the availability of epsilon-N-trimethyllysine limits the rate of carnitine biosynthesis in the growing rat

Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

Science.gov (United States)

2002

This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

Tumor accumulation of {epsilon}-poly-lysines-based polyamines conjugated with boron clusters

Energy Technology Data Exchange (ETDEWEB)

Umano, Masayuki; Uechi, Kazuhiro; Uriuda, Takatoshi; Murayama, Sayuri; Azuma, Hideki [Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 5588585 (Japan); Shinohara, Atsuko [Department of Epidemiology and Environmental Health, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 1138421 (Japan); Liu, Young; Ono, Koji [Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi, Kumatori 5900494 (Japan); Kirihata, Mitsunori [Department of Bioscience and Informatics, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai 5998531 (Japan); Yanagie, Hironobu [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1138656 (Japan); Nagasaki, Takeshi, E-mail: nagasaki@bioa.eng.osaka-cu.ac.jp [Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 5588585 (Japan)

2011-12-15

Boron Neutron Capture Therapy (BNCT) is one of the potent cancer radiotherapies using nuclear reaction between {sup 10}B atoms and the neutron. Whether BNCT will succeed or not depends on tumor selective delivery of {sup 10}B compounds. {epsilon}-Poly-L-lysine is a naturally occurring polyamine characterized by the peptide linkages between the carboxyl and {epsilon}-amino groups of L-lysine. Because of high safety {epsilon}-PLL is applied practically as a food additive due to its strong antimicrobial activity. In this study, we focus on a development of a novel polymeric delivery system for BNCT using biodegradable {epsilon}-PLL conjugated with {sup 10}B-containing clusters (BSH). This polymeric boron carrier will be expected to deliver safely and efficiently into tumor tissues based on Enhanced Permeability and Retention (EPR) effect.

Enhanced Age Strengthening of Mg-Nd-Zn-Zr Alloy via Pre-Stretching

Directory of Open Access Journals (Sweden)

Erjun Guo

2016-08-01

Full Text Available Pre-stretching was carried out to modify the microstructure of Mg-Nd-Zn-Zr alloy to enhance its age strengthening. The results indicated that more heterogeneous nucleation sites can be provided by the high density of dislocations caused by the plastic pre-stretching deformation, as well as speeding up the growth rate of precipitates. Comparison of microstructure in non-pre-stretched specimens after artificial aging showed that pre-stretched specimens exhibited a higher number density of precipitates. The fine and coarse plate-shaped precipitates were found in the matrix. Due to an increase in the number density of precipitates, the dislocation slipping during the deformation process is effectively hindered, and the matrix is strengthened. The yield strength stabilizes at 4% pre-stretching condition, and then the evolution is stable within the error bars. The 8% pre-stretched specimens can achieve an ultimate tensile strength of 297 MPa. However, further pre-stretching strains after 8% cannot supply any increase in strength. Tensile fracture surfaces of specimens subjected to pre-stretching strain mainly exhibit a trans-granular cleavage fracture. This work indicated that a small amount of pre-stretching strain can further increase strength of alloy and also effectively enhance the formation of precipitates, which can expand the application fields of this alloy.

Parallel direct numerical simulation of turbulent flows in rotor-stator cavities. Comparison with k-{epsilon} modeling; Simulation numerique directe parallele d`ecoulements turbulents en cavites rotor-stator comparaisons avec les modilisations k-{epsilon}

Energy Technology Data Exchange (ETDEWEB)

Jacques, R.; Le Quere, P.; Daube, O. [Centre National de la Recherche Scientifique (CNRS), 91 - Orsay (France)

1997-12-31

Turbulent flows between a fixed disc and a rotating disc are encountered in various applications like turbo-machineries or torque converters of automatic gear boxes. These flows are characterised by particular physical phenomena mainly due to the effects of rotation (Coriolis and inertia forces) and thus, classical k-{epsilon}-type modeling gives approximative results. The aim of this work is to study these flows using direct numerical simulation in order to provide precise information about the statistical turbulent quantities and to improve the k-{epsilon} modeling in the industrial MATHILDA code of the ONERA and used by SNECMA company (aerospace industry). The results presented are restricted to the comparison between results obtained with direct simulation and results obtained with the MATHILDA code in the same configuration. (J.S.) 8 refs.

Energy transfer by magnetopause reconnection and the substorm parameter epsilon

International Nuclear Information System (INIS)

Gonzalez-Alarcon, W.D.; Gonzalez, A.L.C. de.

1983-01-01

An expression for the magnetopause reconnection power based on the dawn-dusk component of the reconnection electric field, that reduces to the substorm parameter epsilon for the limit that involves equal geomagnetic (B sub(G)) and magnetosheath (B sub(M)) magnetic field amplitudes at the magnetopause, is contrasted with the expression based on the whole reconnection electric field vector obtained by Gonzalez. The correlation examples of this report show that this (more general) expression for the reconnection power seems to correlate with the empirical dissipation parameter U sub(T) from Akasofu, with slightly better correlation coefficients than those obtained from similar correlations between the parameter epsilon and U sub(T). Thus, these (better) correlations show up for the more familiar values of the ratio B sub(G) / B sub(M) > 1. Nevertheless, the (expected) relatively small difference that seems to exist between these correlation coefficients suggests that, for practical purposes, the parameter epsilon could be used as well (instead of the more general expression) in similar correlation studies due to its impler format. On the other hand, studies that refer mainly to the difference in the magnitudes of epsilon and of the more general expression are expected to give results with less negligible differences. (Author) [pt

Effects of Static Stretching and Playing Soccer on Knee Laxity.

Science.gov (United States)

Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W; Freiwald, Jürgen

2015-11-01

This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Randomized controlled trial. University biomechanics laboratory. Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury. The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes. Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention. There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P soccer of 1.0 ± 1.5 mm (P = 0.001). The ATT increase after static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups. Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer. The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.

Magnitude and duration of stretch modulate fibroblast remodeling.

Science.gov (United States)

Balestrini, Jenna L; Billiar, Kristen L

2009-05-01

Mechanical cues modulate fibroblast tractional forces and remodeling of extracellular matrix in healthy tissue, healing wounds, and engineered matrices. The goal of the present study is to establish dose-response relationships between stretch parameters (magnitude and duration per day) and matrix remodeling metrics (compaction, strength, extensibility, collagen content, contraction, and cellularity). Cyclic equibiaxial stretch of 2-16% was applied to fibroblast-populated fibrin gels for either 6 h or 24 h/day for 8 days. Trends in matrix remodeling metrics as a function of stretch magnitude and duration were analyzed using regression analysis. The compaction and ultimate tensile strength of the tissues increased in a dose-dependent manner with increasing stretch magnitude, yet remained unaffected by the duration in which they were cycled (6 h/day versus 24 h/day). Collagen density increased exponentially as a function of both the magnitude and duration of stretch, with samples stretched for the reduced duration per day having the highest levels of collagen accumulation. Cell number and failure tension were also dependent on both the magnitude and duration of stretch, although stretch-induced increases in these metrics were only present in the samples loaded for 6 h/day. Our results indicate that both the magnitude and the duration per day of stretch are critical parameters in modulating fibroblast remodeling of the extracellular matrix, and that these two factors regulate different aspects of this remodeling. These findings move us one step closer to fully characterizing culture conditions for tissue equivalents, developing improved wound healing treatments and understanding tissue responses to changes in mechanical environments during growth, repair, and disease states.

Notes on the genus Epsilon de Saussure, 1855 (Hymenoptera: Vespidae: Eumeninae) with description of a new species.

Science.gov (United States)

Selis, Marco

2017-11-28

The genus Epsilon de Saussure, 1855, is newly recorded from the Moluccas. New distributional records on Epsilon grandipunctatum Gusenleitner, 1996 are provided. Epsilon rufipes Selis, sp. nov. (Moluccas, Aru islands) is described and figured.

Comparing the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men.

Science.gov (United States)

Ferguson, Steven L; Kim, Eonho; Seo, Dong-Il; Bemben, Michael G

2013-12-01

This study compared the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men. Twenty-one men were randomly assigned to vibration-stretching (VS; n = 8), vibration only (VO; n = 6), or stretching only (SO; n = 7) groups that trained 3 times per week for 3 weeks. All 3 groups performed 9 total sets of 30-second stretches. The VS group performed four 30-second upper-body vibration exercises and five 30-second upper-body stretching exercises. The VO group performed nine 30-second upper-body vibration exercises. The SO group performed nine 30-second upper-body stretching exercises. Shoulder flexion (SF), shoulder extension (SE), and shoulder transverse extension (STE) were assessed by a Leighton Flexometer and back scratch tests bilaterally (BSR, BSL) were measured via tape measure. A 1-way analysis of variance (ANOVA) evaluated groups at baseline and a 2-way repeated-measures ANOVA evaluated the interventions over time. At baseline, there were no group differences in age, height, or weight. There was a significant (p alone or combined with stretching, is a viable alternative to a standard stretching routine when attempting to increase shoulder flexibility. Adding vibration training to a flexibility regimen may improve the likelihood of regularly performing flexibility sessions because of increased variety.

Stretch-minimising stream surfaces

KAUST Repository

Barton, Michael; Kosinka, Jin; Calo, Victor M.

2015-01-01

We study the problem of finding stretch-minimising stream surfaces in a divergence-free vector field. These surfaces are generated by motions of seed curves that propagate through the field in a stretch minimising manner, i.e., they move without stretching or shrinking, preserving the length of their arbitrary arc. In general fields, such curves may not exist. How-ever, the divergence-free constraint gives rise to these 'stretch-free' curves that are locally arc-length preserving when infinitesimally propagated. Several families of stretch-free curves are identified and used as initial guesses for stream surface generation. These surfaces are subsequently globally optimised to obtain the best stretch-minimising stream surfaces in a given divergence-free vector field. Our algorithm was tested on benchmark datasets, proving its applicability to incompressible fluid flow simulations, where our stretch-minimising stream surfaces realistically reflect the flow of a flexible univariate object. © 2015 Elsevier Inc. All rights reserved.

Stretch-minimising stream surfaces

KAUST Repository

Barton, Michael

2015-05-01

We study the problem of finding stretch-minimising stream surfaces in a divergence-free vector field. These surfaces are generated by motions of seed curves that propagate through the field in a stretch minimising manner, i.e., they move without stretching or shrinking, preserving the length of their arbitrary arc. In general fields, such curves may not exist. How-ever, the divergence-free constraint gives rise to these \\'stretch-free\\' curves that are locally arc-length preserving when infinitesimally propagated. Several families of stretch-free curves are identified and used as initial guesses for stream surface generation. These surfaces are subsequently globally optimised to obtain the best stretch-minimising stream surfaces in a given divergence-free vector field. Our algorithm was tested on benchmark datasets, proving its applicability to incompressible fluid flow simulations, where our stretch-minimising stream surfaces realistically reflect the flow of a flexible univariate object. © 2015 Elsevier Inc. All rights reserved.

14-3-3epsilon contributes to tumour suppression in laryngeal carcinoma by affecting apoptosis and invasion

International Nuclear Information System (INIS)

Che, Xing-Hua; Chen, Hong; Xu, Zhen-Ming; Shang, Chao; Sun, Kai-Lai; Fu, Wei-Neng

2010-01-01

14-3-3epsilon regulates a wide range of biological processes, including cell cycle control, proliferation, and apoptosis, and plays a significant role in neurogenesis and the formation of malignant tumours. However, the exact function and regulatory mechanism of 14-3-3epsilon in carcinogenesis have not been elucidated. The expression of 14-3-3epsilon was assessed by RT-PCR and western blotting. The invasiveness and viability of Hep-2 cells were determined by the transwell migration assay and MTT assay, respectively. Cell cycle and apoptosis of Hep-2 cells were detected by flow cytometry. The mRNA and protein expression of 14-3-3epsilon in larynx squamous cell carcinoma (LSCC) tissues were significantly lower than those in clear surgical margin tissues. Statistical analysis showed that the 14-3-3epsilon protein level in metastatic lymph nodes was lower than that in paired tumour tissues. In addition, the protein level of 14-3-3epsilon in stage III or IV tumours was significantly lower than that in stage I or II tumours. Compared with control Hep-2 cells, the percentages of viable cells in the 14-3-3epsilon-GFP and negative control GFP groups were 36.68 ± 14.09% and 71.68 ± 12.10%, respectively. The proportions of S phase were 22.47 ± 3.36%, 28.17 ± 3.97% and 46.15 ± 6.82%, and the apoptotic sub-G1 populations were 1.23 ± 1.02%, 2.92 ± 1.59% and 13.72 ± 3.89% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The percentages of the apoptotic cells were 0.84 ± 0.25%, 1.08 ± 0.24% and 2.93 ± 0.13% in the control, negative control GFP and 14-3-3epsilon-GFP groups, respectively. The numbers of cells that penetrated the filter membrane in the control, negative control GFP and 14-3-3epsilon-GFP groups were 20.65 ± 1.94, 17.63 ± 1.04 and 9.1 ± 0.24, respectively, indicating significant differences among the different groups. Decreased expression of 14-3-3epsilon in LSCC tissues contributes to the initiation and progression of LSCC

Stretching Safely and Effectively

Science.gov (United States)

... shown that stretching immediately before an event weakens hamstring strength. Instead of static stretching, try performing a " ... If you play soccer, for instance, stretch your hamstrings as you're more vulnerable to hamstring strains. ...

The Relation Between Stretching Typology and Stretching Duration: The Effects on Range of Motion.

Science.gov (United States)

Thomas, Ewan; Bianco, Antonino; Paoli, Antonio; Palma, Antonio

2018-04-01

Different stretching strategies and protocols are widely used to improve flexibility or maintain health, acting on the muscle tendon-unit, in order to improve the range of motion (ROM) of the joints. This review aims to evaluate the current body of literature in order to understand the relation between stretching typology and ROM, and secondly to evaluate if a relation exists between stretching volume (either as a single training session, weekly training and weekly frequency) and ROM, after long-term stretching. Twenty-three articles were considered eligible and included in the quantitative synthesis. All stretching typologies showed ROM improvements over a long-term period, however the static protocols showed significant gains (p<0.05) when compared to the ballistic or PNF protocols. Time spent stretching per week seems fundamental to elicit range of movement improvements when stretches are applied for at least or more than 5 min, whereas the time spent stretching within a single session does not seem to have significant effects for ROM gains. Weekly frequency is positively associated to ROM. Evaluated data indicates that performing stretching at least 5 days a week for at least 5 min per week using static stretching may be beneficial to promote ROM improvements. © Georg Thieme Verlag KG Stuttgart · New York.

Knotting in stretched polygons

International Nuclear Information System (INIS)

Rensburg, E J Janse van; Orlandini, E; Tesi, M C; Whittington, S G

2008-01-01

The knotting in a lattice polygon model of ring polymers is examined when a stretching force is applied to the polygon. By examining the incidence of cut-planes in the polygon, we prove a pattern theorem in the stretching regime for large applied forces. This theorem can be used to examine the incidence of entanglements such as knotting and writhing. In particular, we prove that for arbitrarily large positive, but finite, values of the stretching force, the probability that a stretched polygon is knotted approaches 1 as the length of the polygon increases. In the case of writhing, we prove that for stretched polygons of length n, and for every function f(n)=o(√n), the probability that the absolute value of the mean writhe is less than f(n) approaches 0 as n → ∞, for sufficiently large values of the applied stretching force

Large dielectric constant ({epsilon}/{epsilon}{sub 0}>6000) Ba{sub 0.4}Sr{sub 0.6}TiO{sub 3} thin films for high-performance microwave phase shifters

Energy Technology Data Exchange (ETDEWEB)

Carlson, C. M. [Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Rivkin, T. V. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Parilla, P. A. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Perkins, J. D. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Ginley, D. S. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Kozyrev, A. B. [Electrotechnical University of St. Petersburg, St. Petersburg, Russia 197376 (Russian Federation); Oshadchy, V. N. [Electrotechnical University of St. Petersburg, St. Petersburg, Russia 197376 (Russian Federation); Pavlov, A. S. [Electrotechnical University of St. Petersburg, St. Petersburg, Russia 197376 (Russian Federation)

2000-04-03

We deposited epitaxial Ba{sub 0.4}Sr{sub 0.6}TiO{sub 3} (BST) films via laser ablation on MgO and LaAlO{sub 3} (LAO) substrates for tunable microwave devices. Postdeposition anneals ({approx}1100 degree sign C in O{sub 2}) improved the morphology and overall dielectric properties of films on both substrates, but shifted the temperature of maximum dielectric constant (T{sub max}) up for BST/LAO and down for BST/MgO. These substrate-dependent T{sub max} shifts had opposite effects on the room-temperature dielectric properties. Overall, BST films on MgO had the larger maximum dielectric constant ({epsilon}/{epsilon}{sub 0}{>=}6000) and tunability ({delta}{epsilon}/{epsilon}{>=}65%), but these maxima occurred at 227 K. 30 GHz phase shifters made from similar films had figures of merit (ratio of maximum phase shift to insertion loss) of {approx}45 degree sign /dB and phase shifts of {approx}400 degree sign under 500 V ({approx}13 V/{mu}m) bias, illustrating their utility for many frequency-agile microwave devices. (c) 2000 American Institute of Physics.

Allele doses of apolipoprotein E type {epsilon}4 in sporadic late-onset Alzheimer`s disease

Energy Technology Data Exchange (ETDEWEB)

Lucotte, G.; Aouizerate, A.; Gerard, N. [Regional Center of Neurogenetics, Paris (France)] [and others

1995-12-18

Apoliprotein E, type {epsilon}4 allele (ApoE-{epsilon}4) is associated with late-onset sporadic Alzheimer`s disease (AD). We have found that the cumulative probability of remaining unaffected over time decreases for each dose of ApoE-{epsilon}4 in sporadic, late-onset French AD. The effect of genotypes on age at onset of AD was analyzed using the product limit method, to compare unaffected groups during aging. 26 refs., 2 figs., 1 tab.

Growth and microstructure of iron nitride layers and pore formation in {epsilon}-Fe{sub 3}N

Energy Technology Data Exchange (ETDEWEB)

Middendorf, C.; Mader, W. [Univ. Bonn, Inst. fuer Anorganische Chemie, Bonn (Germany)

2003-03-01

Layers of {epsilon}-Fe{sub 3}N and {gamma}'-Fe{sub 4}N on ferrite were produced by nitriding iron single crystals or rolled sheets of iron in flowing ammonia at 520 C. The nitride layers were characterised using X-ray diffraction, light microscopy as well as scanning and transmission electron microscopy. The compound layer consists of {epsilon}-Fe{sub 3}N at the surface and of {gamma}'-Fe{sub 4}N facing the ferrite. After 4 h of nitriding, pores develop in the near surface region of {epsilon}-Fe{sub 3}N showing more or less open porosity. Growth of the entire compound layer as well as of the massive and the porous {epsilon}-Fe{sub 3}N sublayer is diffusion-controlled and follows a parabolic growth rate. The {gamma}'-Fe{sub 4}N layer is formed as a transition phase within a narrow interval of nitrogen activity, and it shows little growth in thickness. The transformation of {gamma}'-Fe{sub 4}N to {epsilon}-Fe{sub 3}N is topotactic, where the orientation of the closed-packed iron layers of the crystal structures is preserved. Determination of lattice plane spacings was possible by X-ray diffraction, and this was correlated to the nitrogen content of {epsilon}-Fe{sub 3}N. While the porous layer exhibits an enhanced nitrogen content corresponding to the chemical composition Fe{sub 3}N{sub 1.1}, the massive e Fe{sub 3}N layer corresponds to Fe{sub 3}N{sub 1.0}. The pore formation in {epsilon}-Fe{sub 3}N{sub 1.1} is concluded to be the result of excess nitrogen atoms on non-structural sites, which have a high mobility. Therefore, recombination of excess nitrogen to molecular N{sub 2} at lattice defects is preferred in {epsilon}-Fe{sub 3}N with high nitrogen content compared to stoichiometric {epsilon}-Fe{sub 3}N{sub 1.0} with nitrogen on only structural sites. (orig.)

Influence of the stretch wrapping process on the mechanical behavior of a stretch film

Science.gov (United States)

Klein, Daniel; Stommel, Markus; Zimmer, Johannes

2018-05-01

Lightweight construction is an ongoing task in packaging development. Consequently, the stability of packages during transport is gaining importance. This study contributes to the optimization of lightweight packaging concepts regarding their stability. A very widespread packaging concept is the distribution of goods on a pallet whereas a Polyethylene (PE) stretch film stabilizes the lightweight structure during the shipment. Usually, a stretch wrapping machine applies this stretch film to the pallet. The objective of this study is to support packaging development with a method that predicts the result of the wrapping process, based on the mechanical characterization of the stretch film. This result is not only defined by the amount of stretch film, its spatial distribution on the pallet and its internal stresses that result in a containment force. More accurate, this contribution also considers the influence of the deformation history of the stretch film during the wrapping process. By focusing on similarities of stretch wrappers rather than on differences, the influence of generalized process parameters on stretch film mechanics and thereby on pallet stability can be determined experimentally. For a practical use, the predictive method is accumulated in an analytic model of the wrapping process that can be verified experimentally. This paves the way for experimental and numerical approaches regarding the optimization of pallet stability.

Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly(epsilon-caprolactone)-b-poly(acrylic acid)

DEFF Research Database (Denmark)

Javakhishvili, Irakli; Hvilsted, Søren

2009-01-01

) of tent-butyl acrylate (tBA) in a controlled fashion by use of NiBr2(PPh3)(2) catalyst to produce Prot-PCL-b-PtBA with narrow polydispersities (1.17-1.39). Subsequent mild deprotection protocols provided HS-PCL-b-PAA. Reduction of a gold salt in the presence of this macroligand under thiol......Amphiphilic poly(epsilon-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) with a thiol functionality in the PCL terminal has been prepared in a novel synthetic cascade. Initially, living anionic ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) employing the difunctional...

Eclipse of epsilon Aurigae

Science.gov (United States)

Templeton, Matthew R.

2009-07-01

The bright, long-period, eclipsing binary star epsilon Aurigae is predicted to begin its next eclipse late July or early August of 2009. Epsilon Aurigae is now past solar conjunction and has reappeared as a morning object. All observers -- both visual and instrumental -- are encouraged to contribute observations of the eclipse during the next two years, beginning immediately for morning observers. Observations are urgently requested right now because it is less likely to be observed in the morning, and the eclipse will begin within the next month. The AAVSO is participating in a global campaign to record this eclipse as part of the International Year of Astronomy 2009 celebrations, organized by the Citizen Sky project (http://www.citizensky.org). For experienced visual observers, please observe this star on a weekly basis, using charts available via VSP from the AAVSO website. For novice visual observers, we recommend participating in this observing program by following the Citizen Sky 10-Star tutorial program, which provides a simple training experience in variable star observing. Photoelectric observers belonging to the AAVSO PEP-V program may submit data as usual via the WebObs feature of the AAVSO website Blue&Gold section. Photoelectric observers may also contribute reduced observations in all filters (including infrared J- and H-bands) directly to the AAVSO via WebObs. Observers using wide-field CCD and DSLR systems are also encouraged to participate; avoid saturating the star. For those with narrower-field systems (D Jeffrey Hopkins are co-leading the precision photometry efforts.

Magnetic measurements of the 10 T superconducting wiggler for the SPring-8 storage ring

CERN Document Server

Batrakov, A; Bekhtenev, E A; Fedurin, M; Hara, M; Karpov, G; Kuzin, M; Mezentsev, N A; Miahara, Y; Shimada, T; Shkaruba, V A; Soutome, K; Tzumaki, K

2001-01-01

In 1999, in the frame of the project ISTC No. 767 'Budker INP/RIKEN Slow Positron Source', the Budker Institute of Nuclear Physics had made a 10 T Three-pole Superconducting Wiggler. The wiggler will be the keystone of this project by its installation on the SPring-8 storage ring for powerful gamma ray generation (lambda sub c =450 keV), that will be used for slow positron production (N subgamma(epsilon>1 MeV)approx 10 sup 1 sup 5 , gamma/s I sub e =0.1 A). A. Ando et al., Proposal of the high magnetic field super conducting WLS for slow positron source at SPring-8, presented at SR1 '97 Conference. In January, 2000, the wiggler was transported to SPring-8, where the last test and measurements were carried out in collaboration with Japan. In this article, the results of measurements of the magnetic field, finding the magnetic field amplitude by an NMR probe, the definition of feed current relations by stretch current wire method, the calibration of a Hall probe in the high magnetic field, and the measurement o...

Static versus dynamic stretching: Chronic and acute effects on Agility performance in male athletes

Directory of Open Access Journals (Sweden)

Iman Taleb-Beydokhti

2015-04-01

Full Text Available The purpose of this study was to examine the acute and chronic effects of static & dynamic stretching protocols on agility performance in amateur handball players. Twelve male amateur handball players (age: 19.66 ± 4.02 years old, weight: 67.12 ± 8.73 kg, height: 178.29 ± 7.81 cm participated in this study. The athletes were randomly allocated into two groups: static stretching or dynamic stretching. All of them underwent an initial evaluation and were submitted to the first intervention. They were evaluated once again and at the end of 12 training sessions. The results analyzed using ANOVA showed that there was a significant decrease in agility time after dynamic stretching against no stretching in the acute phase; but, there were no significant differences between dynamic stretching and no stretching in the chronic phase. In addition, there was no a significant difference between no stretching and static stretching in the acute phase; while, There was a significant decrease in agility time after no stretching against static stretching in the chronic phase. It was concluded that acute dynamic stretching as part of a warm-up may decrease agility time performance, whereas static stretching seems to increase agility time performance. Consequently, the acute and chronic static stretching should not be performed prior to an explosive athletic performance. Keywords: Handball, Agility, Dynamic stretching, Static stretching

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility.

Science.gov (United States)

Wong, Del P; Chaouachi, Anis; Lau, Patrick W C; Behm, David G

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key pointsThe duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001).No significant differences in RSA and COD between the 3 stretching conditions.The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects.The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments.

Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

Science.gov (United States)

Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

2011-01-01

This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

Passive Stretch Versus Active Stretch on Intervertebral Movement in Non - Specific Neck Pain

International Nuclear Information System (INIS)

Abd El - Aziz, A.H.; Amin, D.I.; Moustafa, I.

2016-01-01

Neck pain is one of the most common and painful musculoskeletal conditions. Point prevalence ranges from 6% to 22% and up to 38% of the elderly population, while lifetime prevalence ranges from 14,2% to 71%. Up till now no randomized study showed the effect between controversy of active and passive stretch on intervertebral movement. The purpose: the current study was to investigate the effect of the passive and active stretch on intervertebral movement in non - specific neck pain. Material and methods: Forty five subjects from both sexes with age range between 18 and 30 years and assigned in three groups, group I (15) received active stretch, ultrasound and TENS. Group II (15) received passive stretch, ultrasound and TENS. Group III (15) received ultrasound and TENS. The radiological assessment was used to measure rotational and translational movement of intervertebral movement before and after treatment. Results: MANOVA test was used for radiological assessment before and after treatment there was significant increase in intervertebral movement in group I as p value =0.0001. Conclusion: active stretch had a effect in increasing the intervertebral movement compared to the passive stretch

Dose-dependent utilisation of casein-linked lysinoalanine, N(epsilon)-fructoselysine and N(epsilon)-carboxymethyllysine in rats.

Science.gov (United States)

Somoza, Veronika; Wenzel, Elisabeth; Weiss, Carola; Clawin-Rädecker, Ingrid; Grübel, Nadine; Erbersdobler, Helmut F

2006-09-01

During the heat treatment of protein-containing foods, the amino acid lysine is most prone to undergo chemical reactions in the course of amino acid cross-linking or Maillard reactions. Among the reaction products formed, lysinoalanine (LAL), N(epsilon)-fructoselysine (FL) and N(epsilon)-carboxymethyllysine (CML) are those which serve as sensitive markers for the heat treatment applied. From a nutritional perspective, these compounds are ingested with the diet in considerable amounts but information about their metabolic transit and putative in vivo effects is scarce. In the present study, casein-linked LAL, FL and CML were administered to rats in two different doses for 10 days. Quantitation of LAL, FL and CML in plasma, tissue and faeces samples revealed that the kidneys are the predominant sites of accumulation and excretion. The maximum percent of dietary LAL, FL and CML excreted in the urine was 5.6, 5.2 and 29%, whereas the respective recoveries in the kidneys were 0.02, 26 and 1.4%. The plasma and tissue analyses revealed that the endogenous load of either compound is increased by its dietary intake. But the dose-dependent utilisation of dietary protein-linked LAL, FL and CML in rats has been demonstrated for the first time to vary substantially from each other.

Modeling of lipase catalyzed ring-opening polymerization of epsilon-caprolactone.

Science.gov (United States)

Sivalingam, G; Madras, Giridhar

2004-01-01

Enzymatic ring-opening polymerization of epsilon-caprolactone by various lipases was investigated in toluene at various temperatures. The determination of molecular weight and structural identification was carried out with gel permeation chromatography and proton NMR, respectively. Among the various lipases employed, an immobilized lipase from Candida antartica B (Novozym 435) showed the highest catalytic activity. The polymerization of epsilon-caprolactone by Novozym 435 showed an optimal temperature of 65 degrees C and an optimum toluene content of 50/50 v/v of toluene and epsilon-caprolactone. As lipases can degrade polyesters, a maximum in the molecular weight with time was obtained due to the competition of ring opening polymerization and degradation by specific chain end scission. The optimum temperature, toluene content, and the variation of molecular weight with time are consistent with earlier observations. A comprehensive model based on continuous distribution kinetics was developed to model these phenomena. The model accounts for simultaneous polymerization, degradation and enzyme deactivation and provides a technique to determine the rate coefficients for these processes. The dependence of these rate coefficients with temperature and monomer concentration is also discussed.

SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

Directory of Open Access Journals (Sweden)

Del P. Wong

2011-06-01

Full Text Available This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA and change of direction (COD. Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s. Three dynamic stretching exercises of 30 s duration were then performed (90 s total. Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p < 0.001. However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (< 90 s static stretching may not have provided sufficient stimulus to elicit performance impairments

A Japanese Stretching Intervention Can Modify Lumbar Lordosis Curvature.

Science.gov (United States)

Kadono, Norio; Tsuchiya, Kazushi; Uematsu, Azusa; Kamoshita, Hiroshi; Kiryu, Kazunori; Hortobágyi, Tibor; Suzuki, Shuji

2017-08-01

Eighteen healthy male adults were assigned to either an intervention or control group. Isogai dynamic therapy (IDT) is one of Japanese stretching interventions and has been practiced for over 70 years. However, its scientific quantitative evidence remains unestablished. The objective of this study was to determine whether IDT could modify lumbar curvature in healthy young adults compared with stretching exercises used currently in clinical practice. None of previous studies have provided data that conventional stretching interventions could modify spinal curvatures. However, this study provides the first evidence that a specific form of a Japanese stretching intervention can acutely modify the spinal curvatures. We compared the effects of IDT, a Japanese stretching intervention (n=9 males), with a conventional stretching routine (n=9 males) used widely in clinics to modify pelvic tilt and lumbar lordosis (LL) angle. We measured thoracic kyphosis (TK) and LL angles 3 times during erect standing using the Spinal Mouse before and after each intervention. IDT consisted of: (1) hip joint correction, (2) pelvic tilt correction, (3) lumbar alignment correction, and (4) squat exercise stretch. The control group performed hamstring stretches while (1) standing and (2) sitting. IDT increased LL angle to 25.1 degrees (±5.9) from 21.2 degrees (±6.9) (P=0.047) without changing TK angle (pretest: 36.8 degrees [±6.9]; posttest: 36.1 degrees [±6.5]) (P=0.572). The control group showed no changes in TK (P=0.819) and LL angles (P=0.744). IDT can thus be effective for increasing LL angle, hence anterior pelvic tilt. Such modifications could ameliorate low back pain and improve mobility in old adults with an unfavorable pelvic position.

Methods for thermal inactivation of pathogens in mozzarella: a comparison between stretching and pasteurization

Directory of Open Access Journals (Sweden)

D.C. Raimundo

2013-04-01

Full Text Available This study aimed to evaluate the efficiency of stretching in the reduction of pathogens when compared to milk pasteurization, the official method to ensure safe cheese production. Whole buffalo milk was contaminated with Mycobacterium fortuitum, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Part of the milk was used in mozzarella production and the other part was submitted to holder pasteurization. Pathogens were quantified before and after thermal processing (mozzarella stretching and milk pasteurization. Pasteurization and stretching led to the following reductions in log cycles, respectively: 4.0 and 6.3 for Mycobacterium sp.; 6.0 and 8.4 for Listeria sp.; >6.8 and 4.5 for Staphylococcus sp.; and >8.2 and 7.5 for Salmonella sp.

DMPD: Protein kinase C epsilon: a new target to control inflammation andimmune-mediated disorders. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 14643884 Protein kinase C epsilon: a new target to control inflammation andimmune-m...g) (.html) (.csml) Show Protein kinase C epsilon: a new target to control inflammation andimmune-mediated di...sorders. PubmedID 14643884 Title Protein kinase C epsilon: a new target to contro

Stretch strength of Al-Li alloy sheet

Energy Technology Data Exchange (ETDEWEB)

Sato, K.; Sawa, Y.; Yokoyama, T.; Fujimoto, S. [Science Univ. of Tokyo (Japan). Dept. of Mech. Eng.; Sakamoto, T. [Kobe Steel Works, Tokyo (Japan)

1998-07-01

Stretch test on Al-Li alloy sheet was carried out in stretch rate of 0.01 to 0.2 mm/sec. The limiting stretch depth was measured in various conditions and the following results were obtained. (1) Stretch rate does not affect the limiting stretch depth of Al-Li alloy. (2) The limiting stretch depth is increased with increase of the profile radius. (3) Strain hardening exponent(n-value) and r-value of Lankford do not affect the limiting stretch depth. (4) Rapture pattern in stretch test of Al is {alpha} type rapture and that of Al-Li alloy is straight line type rapture. (orig.) 4 refs.

Acute effect of static stretching on muscle force in older women

Directory of Open Access Journals (Sweden)

André Luiz Demantova Gurjão

2010-04-01

Full Text Available The objective of this study was to investigate the acute effect of static stretching on the peak rate of force development (PRFD and maximum voluntary contraction (MVC in older women. Ten women (68.5 ± 7.0 years; 70.9 ± 8.1 kg; 159.4 ± 6.0 cm; body mass index: 28.0 ± 3.8 kg/m2 were studied. MVC and PRFD were determined by leg press exercise before and after the control or stretching condition (three sets of 30 seconds of static stretching of the quadriceps on two different days (interval of 24 hours. PRFD was determined as the steepest slope of the curve, calculated within regular windows of 20 milliseconds (∆force/∆time for the first 200 milliseconds after the onset of contraction. MVC was determined as the highest value recorded in each set. Only one condition was tested on each day and the order of application of each condition was determined randomly. The stretching intensity was evaluated by the muscle pain threshold. Four post-condition assessments (post-treatment, 10, 20, and 30 minutes were performed to monitor muscle strength. ANCOVA 2x5, followed by the Scheffé post-hoc test, showed no significant interactions between conditions vs. times (P > 0.05 for PRFD or MVC. In conclusion, acute bouts of static stretching of the quadriceps femoris do not affect the ability of rapid and maximum muscle force production in older women.

Biodegradable p(DLLA-epsilon-CL) nerve guides versus autologous nerve grafts : Electromyographic and video analysis

NARCIS (Netherlands)

Meek, MF; Nicolai, JPA; Gramsbergen, A; van der Werf, J.F.A.

The aim of this study was to evaluate the functional effects of bridging a gap in the sciatic nerve of the rat with either a biodegradable copolymer of (DL)-lactide and epsilon -caprolactone [p(DLLA-epsilon -CL)] nerve guide or an autologous nerve graft. Electromyograms (EMGs) of the gastrocnemius

APOE epsilon4 is associated with impaired verbal learning in patients with MS.

Science.gov (United States)

Koutsis, G; Panas, M; Giogkaraki, E; Potagas, C; Karadima, G; Sfagos, C; Vassilopoulos, D

2007-02-20

To investigate the effect of APOE epsilon4 on different cognitive domains in a population of Greek patients with multiple sclerosis (MS). A total of 125 patients with MS and 43 controls were included in this study and underwent neuropsychological assessment with Rao's Brief Repeatable Battery. All patients with MS were genotyped for APOE. The effect of APOE epsilon4 on different cognitive domains was investigated. Fifty-one percent of patients with MS were cognitively impaired. E4 carriers had a sixfold increase in the relative risk of impairment in verbal learning vs noncarriers (OR 6.28, 95% CI 1.74 to 22.69). This effect was domain-specific and was not observed in other cognitive domains assessed by the battery. We found an association of APOE epsilon4 with impaired verbal learning in patients with multiple sclerosis.

The effects of stretching on the flexibility, muscle performance and functionality of institutionalized older women

Directory of Open Access Journals (Sweden)

D. Gallon

2011-03-01

Full Text Available Stretching has been widely used to increase the range of motion. We assessed the effects of a stretching program on muscle-tendon length, flexibility, torque, and activities of daily living of institutionalized older women. Inclusion/exclusion criteria were according to Mini-Mental State Examination (MMSE (>13, Barthel Index (>13 and Lysholm Scoring Scale (>84. Seventeen 67 ± 9 year-old elderly women from a nursing home were divided into 2 groups at random: the control group (CG, N = 9 participated in enjoyable cultural activities; the stretching group (SG, N = 8 performed active stretching of hamstrings, 4 bouts of 1 min each. Both groups were supervised three times per week over a period of 8 weeks. Peak torque was assessed by an isokinetic method. Both groups were evaluated by a photogrammetric method to assess muscle-tendon length of uni- and biarticular hip flexors and hamstring flexibility. All measurements were analyzed before and after 8 weeks by two-way ANOVA with the level of significance set at 5%. Hamstring flexibility increased by 30% in the SG group compared to pre-training (76.5 ± 13.0° vs 59.5 ± 9.0°, P = 0.0002 and by 9.2% compared to the CG group (76.5 ± 13.0° vs 64.0 ± 12.0°, P = 0.0018. Muscle-tendon lengths of hip biarticular flexor muscles (124 ± 6.8° vs 118.3 ± 7.6°, 5.0 ± 7.0%, P = 0.031 and eccentric knee extensor peak torque were decreased in the CG group compared to pre-test values (-49.4 ± 16.8 vs -60.5 ± 18.9 Nm, -15.7 ± 20%, P = 0.048. The stretching program was sufficient to increase hamstring flexibility and a lack of stretching can cause reduction of muscle performance.

Acute effect of passive rest intervals and stretching exercise on multiple set performance

Directory of Open Access Journals (Sweden)

Antonio Claudio do Rosário Souza

2009-01-01

Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n4p435 The objective of this study was to determine the acute effect of passive rest intervals and static stretching between resistance exercise sets on the number of maximal repetitions (RM, rating of perceived exertion (RPE, and cumulative number of repetitions in multiple sets with a workload adjusted by the 8RM test. Fourteen trained male subjects (24.4 ± 2.1 years; 79.1 ± 7.1 kg; 175.4 ± 5.6 cm were studied. On the first two visits, the subjects were submitted to the test and 8RM re-test using chest press (CP and squat (SQ exercises. On the two subsequent visits, all subjects were randomly assigned to two experimental situations: a 8RM test with a passive rest interval (PI; b 8RM test with static stretching (SS. The subjects performed three sets of CP and SQ, intercalated with 2 minutes of passive rest or 30 seconds of static stretching. ANOVA revealed a significant decrease (p < 0.05 in the second (PI = 6 ± 0.8 x SS = 5.2 ± 1.0 repetitions and third (PI = 4.1 ± 0.8 X SS = 3.3 ± 0.6 repetitions sets for CP and only in the third set (PI = 4.9 ± 0.8 X SS = 4.2 ± 1.0 repetitions for SQ. For RPE, the Wilcoxon test showed significant differences (p < 0.05 between all sets for CP and SQ. For the cumulative number of repetitions, the paired t-test revealed a significant decrease (p < 0.05 for CP (PI = 18.3 ± 1.5 X SS = 16.8 ± 1.6 repetitions. These results indicate that static stretching between resistance exercise sets decreases 8RM test performance.

Jack-knife stretching promotes flexibility of tight hamstrings after 4 weeks: a pilot study.

Science.gov (United States)

Sairyo, Koichi; Kawamura, Takeshi; Mase, Yasuyoshi; Hada, Yasushi; Sakai, Toshinori; Hasebe, Kiyotaka; Dezawa, Akira

2013-08-01

Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to -8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p hamstrings.

IUE observations of the eclipsing binary Epsilon Aurigae

International Nuclear Information System (INIS)

Hack, M.; Selvelli, P.L.

1978-01-01

It is stated that the eclipsing binary Epsilon Aur is a most peculiar binary system and it has not been explained satisfactorily. Observations of this system using the International Ultraviolet Explorer (IUE) collected at the Villafranca Satellite Tracking Station of the European Space Agency are here reported. (author)

Atomic Stretch: Optimally bounded real-time stretching and beyond

DEFF Research Database (Denmark)

Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll

2016-01-01

Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color-modification, co......Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color...

The acute effect of static and dynamic stretching during warm-ups on anaerobic performance in trained women

Directory of Open Access Journals (Sweden)

rouhollah haghshenas

2014-09-01

Full Text Available The purpose of this study was to investigate effects of static stretching, dynamic stretching and no stretching methods on power and speed in volleyball players. Therefore, Twenty-four volleyball players (height: 173.29 ± 7.81 m; mass: 62.12 ± 8.73 kg; age: 22.66 ± 4.02 years; experience: 3.27 ± 6.37 were tested for speed performance using the 20 meter sprint test and also for power using vertical jump test after static stretching, dynamic stretching and no stretching. The results analyzed using ANOVA showed that There was a significant increase in height jump after dynamic stretching against static stretching. But, there were no significant differences between no stretching and static stretching groups. In addition, there was a significant decrease in time 20 meter sprint after dynamic stretching against static stretching and no stretching groups. The results of this study suggest that it may be desirable for volleyball players to perform dynamic exercises before the performance of activities that require a high power output.

Biodistribution and catabolism of 18F-labeled N-epsilon-fructoselysine as a model of Amadori products.

Science.gov (United States)

Hultsch, Christina; Hellwig, Michael; Pawelke, Beate; Bergmann, Ralf; Rode, Katrin; Pietzsch, Jens; Krause, René; Henle, Thomas

2006-10-01

Amadori products are formed in the early stage of the so-called Maillard reaction between reducing sugars and amino acids or proteins. Such nonenzymatic glycosylation may occur during the heating or storage of foods, but also under physiological conditions. N-epsilon-fructoselysine is formed via this reaction between the epsilon-amino group of peptide-bound lysine and glucose. Despite the fact that, in certain heated foods, up to 50% of lysyl moieties may be modified to such lysine derivatives, up to now, very little is known about the metabolic fate of alimentary administered Amadori compounds. In the present study, N-succinimidyl-4-[18F]fluorobenzoate was used to modify N-epsilon-fructoselysine at the alpha-amino group of the lysyl moiety. The in vitro stability of the resulting 4-[18F]fluorobenzoylated derivative was tested in different tissue homogenates. Furthermore, the 4-[18F]fluorobenzoylated N-epsilon-fructoselysine was used in positron emission tomography studies, as well as in studies concerning biodistribution and catabolism. The results show that the 4-[18F]fluorobenzoylated N-epsilon-fructoselysine is phosphorylated in vitro, as well as in vivo. This phosphorylation is caused by fructosamine 3-kinases and occurs in vivo, particularly in the kidneys. Despite the action of these enzymes, it was shown that a large part of the intravenously applied radiolabeled N-epsilon-fructoselysine was excreted nearly unchanged in the urine. Therefore, it was concluded that the predominant part of peptide-bound lysine that was fructosylated during food processing is not available for nutrition.

Regulation of CCK-induced ERK1/2 activation by PKC epsilon in rat pancreatic acinar cells

Directory of Open Access Journals (Sweden)

Chenwei Li

2017-11-01

Full Text Available The extracellular signal-regulated kinase ERK1/2 is activated in pancreatic acinar cells by cholecystokinin (CCK and other secretagogues with this activation mediated primarily by protein kinase C (PKC. To identify the responsible PKC isoform, we utilized chemical inhibitors, cell permeant inhibitory peptides and overexpression of individual PKC dominant negative variants by means of adenoviral vectors. While the broad-spectrum PKC inhibitor GF109203X strongly inhibited ERK1/2 activation induced by 100 pM CCK, Go6976 which inhibits the classical PKC isoforms (alpha, beta and gamma, as well as Rottlerin, a specific PKC delta inhibitor, had no inhibitory effect. To test the role of PKC epsilon, we used specific cell permeant peptide inhibitors which block PKC interaction with their intracellular receptors or RACKs. Only PP93 (PKC epsilon peptide inhibitor inhibited CCK-induced ERK1/2 activation, while PP95, PP101 and PP98, which are PKC alpha, delta and zeta peptide inhibitors respectively, had no effect. We also utilized adenovirus to express dominant negative PKC isoforms in pancreatic acini. Only PKC epsilon dominant negative inhibited CCK-induced ERK1/2 activation. Dominant negative PKC epsilon expression similarly blocked the effect of carbachol and bombesin to activate ERK1/2. Immunoprecipitation results demonstrated that CCK can induce an interaction of c-Raf-1 and PKC epsilon, but not that of other isoforms of Raf or PKC. We conclude that PKC epsilon is the isoform of PKC primarily involved with CCK-induced ERK1/2 activation in pancreatic acinar cells.

How to determine local stretching and tension in a flow-stretched DNA molecule

DEFF Research Database (Denmark)

Pedersen, Jonas Nyvold; Marie, Rodolphe; Kristensen, Anders

2016-01-01

We determine the nonuniform stretching of and tension in amega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead......, we analyze the transverse thermal motion of the DNA. Tension at the center of the DNA adds up to 16 pN, giving almost fully stretched DNA. This method was devised for optical mapping of DNA, specifically, DNA denaturation patterns. It may be useful also for other studies, e.g., DNA......-protein interactions, specifically, their tension dependence. Generally, wherever long strands of DNA—e.g., native DNA extracted from human cells or bacteria—must be stretched with ease for inspection, this method applies....

DMPD: Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 18353649 Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activa...e IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? PubmedID... 18353649 Title Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? Authors Chau

Sequence-length variation of mtDNA HVS-I C-stretch in Chinese ethnic groups.

Science.gov (United States)

Chen, Feng; Dang, Yong-hui; Yan, Chun-xia; Liu, Yan-ling; Deng, Ya-jun; Fulton, David J R; Chen, Teng

2009-10-01

The purpose of this study was to investigate mitochondrial DNA (mtDNA) hypervariable segment-I (HVS-I) C-stretch variations and explore the significance of these variations in forensic and population genetics studies. The C-stretch sequence variation was studied in 919 unrelated individuals from 8 Chinese ethnic groups using both direct and clone sequencing approaches. Thirty eight C-stretch haplotypes were identified, and some novel and population specific haplotypes were also detected. The C-stretch genetic diversity (GD) values were relatively high, and probability (P) values were low. Additionally, C-stretch length heteroplasmy was observed in approximately 9% of individuals studied. There was a significant correlation (r=-0.961, Ppopulations. The results from the Fst and dA genetic distance matrix, neighbor-joining tree, and principal component map also suggest that C-stretch could be used as a reliable genetic marker in population genetics.

Redundant role of protein kinase C delta and epsilon during mouse embryonic development.

Directory of Open Access Journals (Sweden)

Sergio Carracedo

Full Text Available Protein Kinase C delta and epsilon are mediators of important cellular events, such as cell proliferation, migration or apoptosis. The formation of blood vessels, i.e., vasculo- and angiogenesis, is a process where these isoforms have also been shown to participate. However, mice deficient in either Protein Kinase C delta or epsilon are viable and therefore their individual contribution to the formation of the vasculature appeared so far dispensable. In this study, we show that double null mutation of Protein Kinase C delta and epsilon causes embryonic lethality at approximately E9.5. At this stage, whole mount staining of the endothelial marker CD31 in double null embryos revealed defective blood vessel formation. Moreover, culture of double deficient mouse allantois showed impaired endothelial cell organization, and analyses of double deficient embryo sections showed dilated vessels, decreased endothelial-specific adherent junctions, and decreased contact of endothelial cells with mural cells. Protein kinase C delta and epsilon also appeared essential for vascular smooth muscle cell differentiation, since α-smooth muscle actin, a classical marker for vascular smooth muscle cells, was almost undetectable in double deficient embryonic aorta at E9.5. Subsequent qPCR analyses showed decreased VE-cadherin, Vegfr2, Cd31, Cdh2, Ets1, and Fli-1, among other angiogenesis related transcripts in double deficient embryos. Taken together, these data suggest for the first time an in vivo redundant role between members of the novel Protein Kinase C subfamily that allows for mutual compensation during mouse embryonic development, with vasculogenesis/angiogenesis as an obvious common function of these two Protein Kinase Cs. Protein Kinase C delta and epsilon might therefore be useful targets for inhibiting vasculo- and/or angiogenesis.

Analysis of a filament stretching rheometer

DEFF Research Database (Denmark)

Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

1996-01-01

A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown.......A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown....

EFFICACY OF MODIFIED PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING WITH CRYOTHERAPY OVER MANUAL PASSIVE STRETCHING WITH CRYOTHERAPY ON HAMSTRING FLEXIBILITY

Directory of Open Access Journals (Sweden)

Shamik Bhattacharjee

2016-04-01

Full Text Available Background: Healthy individuals, to ease and accomplish their activities of daily living they need flexible body without any tightness in the muscles, particularly those used for a definite function. Cooling soft tissues in a lengthened position after stretching has been shown to promote more lasting increases in soft tissue length and minimize post stretch muscle soreness. There are less documented studies which compared modified proprioceptive neuromuscular facilitation (PNF stretch over passive manual stretch with cold application commonly after the interventions. Methods: Thirty high school going healthy students were divided into two groups- Group I received Passive Manual stretching (n=15 and Group II received modified PNF stretching (n=15 and both groups received cold application after the interventions for 10 minutes commonly for 5 days. ROM was taken on day 1, day 5 and day 7. Results: After day 7, Group II with Modified PNF stretching along with cold application showed a significant increase in range of motion tested with active knee extension test (AKET. Conclusion: Modified PNF stretching is considered to be the effective intervention in increasing and maintaining ROM in AKET over passive manual stretching with cold applications commonly after the interventions.

Asymmetries in global-local processing ability in elderly people with the apolipoprotein e-epsilon4 allele.

Science.gov (United States)

Jacobson, Mark W; Delis, Dean C; Lansing, Amy; Houston, Wes; Olsen, Ryan; Wetter, Spencer; Bondi, Mark W; Salmon, David P

2005-11-01

Previous studies have identified cognitive asymmetries in elderly people at increased risk for Alzheimer's disease (AD) by comparing standardized neuropsychological tests of verbal and spatial abilities in both preclinical AD and apolipoprotein epsilon4+ elderly groups. This prospective study investigated cognitive asymmetries within a single test by comparing cognitively intact elderly (with and without the epsilon4+ allele) on a learning and memory measure that uses global and local visuospatial stimuli. Both groups demonstrated comparable overall learning and recall. But the epsilon4+ group had a significantly larger discrepancy between their global and local learning scores and had a greater proportion of individuals with more than a one standard deviation difference between their immediate recall of the global and local elements, relative to the epsilon4- group. These findings build on previous studies identifying subgroups of elderly people at greater risk for AD who often demonstrate increased cognitive asymmetries relative to groups without significant risk factors. Copyright (c) 2005 APA, all rights reserved.

Fyn kinase controls Fc{epsilon}RI receptor-operated calcium entry necessary for full degranulation in mast cells

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Miranda, Elizabeth; Ibarra-Sanchez, Alfredo [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados (Cinvestav), Sede Sur, Calzada de los Tenorios 235, Col. Granjas Coapa, CP 14330 Mexico City (Mexico); Gonzalez-Espinosa, Claudia, E-mail: cgonzal@cinvestav.mx [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados (Cinvestav), Sede Sur, Calzada de los Tenorios 235, Col. Granjas Coapa, CP 14330 Mexico City (Mexico)

2010-01-22

IgE-antigen-dependent crosslinking of the high affinity IgE receptor (Fc{epsilon}RI) on mast cells leads to degranulation, leukotriene synthesis and cytokine production. Calcium (Ca{sup 2+}) mobilization is a sine qua non requisite for degranulation, allowing the rapid secretion of stored pro-inflammatory mediators responsible for allergy symptoms. Fyn is a Src-family kinase that positively controls Fc{epsilon}RI-induced mast cell degranulation. However, our understanding of the mechanism connecting Fyn activation to secretion of pre-synthesized mediators is very limited. We analyzed Fc{epsilon}RI-dependent Ca{sup 2+} mobilization in bone marrow-derived mast cells (BMMCs) differentiated from WT and Fyn -/- knock out mice. Fyn -/- BMMCs showed a marked defect in extracellular Ca{sup 2+} influx after Fc{epsilon}RI crosslinking but not after thapsigargin addition. High concentrations of Gadolinium (Gd{sup 3+}) partially blocked Fc{epsilon}RI-induced Ca{sup 2+} influx in WT cells but, in contrast, completely inhibited Ca{sup 2+} mobilization in Fyn -/- cells. Low concentrations of an inhibitor of the canonical transient receptor potential (TRPC) Ca{sup 2+} channels (2-aminoethoxyphenyl-borane, 2-APB) blocked Fc{epsilon}RI-induced maximal Ca{sup 2+} rise in WT but not in Fyn -/- cells. Ca{sup 2+} entry through Fyn-controlled, 2-APB sensitive channels was found to be important for full degranulation and IL-2 mRNA accumulation in WT cells. Immunoprecipitation assays showed that Fyn kinase interacts with TRPC 3/6/7 channels after IgE-antigen stimulation, but its association is not related to protein tyrosine phosphorylation. Results indicate Fyn kinase mediates the receptor-dependent activation of TRPC channels that contribute to degranulation in Fc{epsilon}RI-stimulated mast cells.

Tunable magnetization of infrared epsilon-near-zero media via field-effect modulation

Science.gov (United States)

Salary, Mohammad Mahdi; Mosallaei, Hossein

2018-04-01

In this letter, we demonstrate that field effect modulation enables electrical tuning of the effective permeability of epsilon-near-zero (ENZ) media at infrared frequencies. In particular, hexagonal silicon carbide (6H-SiC) is incorporated as an epsilon-near-zero host in a gated 6H-SiC/SiO2/Si heterostructure. The change in the applied voltage leads to a change in the carrier concentration of the accumulation layer formed at the interface of 6H-SiC and SiO2 which can alter the effective permeability of the heterostructure by virtue of the photonic doping effect. We will rigorously model and analyze the structure by linking charge transport and electromagnetic models. The presented mechanism allows for tuning the impedance and magnetization of ENZ materials in real-time while capturing extreme cases of epsilon-and-mu-near-zero and magnetic conductor. As such, it can be used for various applications such as real-time engineering of thermal emission, dynamic switching, reconfigurable tunneling, and holography.

EFFECTS OF DYNAMIC AND STATIC STRETCHING WITHIN GENERAL AND ACTIVITY SPECIFIC WARM-UP PROTOCOLS

Directory of Open Access Journals (Sweden)

Michael Samson

2012-06-01

Full Text Available The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1 general aerobic warm-up with static stretching, 2 general aerobic warm-up with dynamic stretching, 3 general and specific warm-up with static stretching and 4 general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance, countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013 in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch condition increased sit and reach range of motion (ROM by 2.8% more (p = 0.0083 than the dynamic condition. These results would support the use of static stretching within an activity specific warm-up to ensure maximal ROM along with an enhancement in sprint performance

Epsilon Aur monitoring during predicted pulsation phase

Science.gov (United States)

Waagen, Elizabeth O.; Templeton, Matthew R.

2014-09-01

Dr. Robert Stencel (University of Denver Astronomy Program) has requested that AAVSO observers monitor epsilon Aurigae from now through the end of the observing season. "Studies of the long-term, out-of-eclipse photometry of this enigmatic binary suggest that intervals of coherent pulsation occur at roughly 1/3 of the 27.1-year orbital period. Kloppenborg, et al. noted that stable variation patterns develop at 3,200-day intervals' implying that 'the next span of dates when such events might happen are circa JD ~2457000 (2014 December)'. "These out-of-eclipse light variations often have amplitudes of ~0.1 magnitude in U, and ~0.05 in V, with characteristic timescales of 60-100 days. The AAVSO light curve data to the present may indicate that this coherent phenomenon has begun, but we encourage renewed efforts by observers...to help deduce whether these events are internal to the F star, or externally-driven by tidal interaction with the companion star." Nightly observations or one observation every few days (CCD/PEP/DSLR, VUBR (amplitude too small for visual)) are requested. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. Epsilon Aur was the subject of major international campaigns and the AAVSO's Citizen Sky project as it went through its 27.1-year eclipse in 2009-2011. Over 700 observers worldwide submitted over 20,000 multicolor observations to the AAVSO International Database for this project. Much information on eps Aur is available from the AAVSO, including material on the Citizen Sky website (http://www.aavso.org/epsilon-aurigae and http://www.citizensky.org/content/star-our-project). The Journal of the AAVSO, Volume 40, No. 2 (2012) was devoted to discussion of and research results from this event. See full Alert Notice for more details and observations.

Flexibility and stretching physiology : responses and adaptations to different stretching intensities.

OpenAIRE

Freitas, Sandro Remo Martins Neves Ramos

2014-01-01

Doutoramento em Motricidade Humana, especialidade de Biomecânica Research and reported literature regarding the conceptual, methodological, and training effects of stretching with different intensities are scarce. The purposes of this thesis were to: i) explore and develop methodological conditions to achieve the second purpose (studies: 1 to 3); ii) characterize the acute and chronic effects induced by different stretching intensities on skeletal muscle and joint mechanical properti...

Broadband perfect infrared absorption by tuning epsilon-near-zero and epsilon-near-pole resonances of multilayer ITO nanowires.

Science.gov (United States)

Zhou, Kun; Cheng, Qiang; Song, Jinlin; Lu, Lu; Jia, Zhihao; Li, Junwei

2018-01-01

We numerically investigate the broadband perfect infrared absorption by tuning epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) resonances of multilayer indium tin oxide nanowires (ITO NWs). The monolayer ITO NWs array shows intensive absorption at ENZ and ENP wavelengths for p polarization, while only at the ENP wavelength for s polarization. Moreover, the ENP resonances are almost omnidirectional and the ENZ resonances are angularly dependent. Therefore, the absorption bandwidth is broader for p polarization than that for s polarization when polarized waves are incident obliquely. The ENZ resonances can be tuned by altering the doping concentration and volume filling factor of ITO NWs. However, the ENP resonances only can be tuned by changing the doping concentration of ITO NWs, and volume filling factor impacts little on the ENP resonances. Based on the strong absorption properties of each layer at their own ENP and ENZ resonances, the tuned absorption of the bilayer ITO NWs with the different doping concentrations can be broader and stronger. Furthermore, multilayer ITO NWs can achieve broadband perfect absorption by controlling the doping concentration, volume filling factor, and length of the NWs in each layer. This study has the potential to apply to applications requiring efficient absorption and energy conversion.

1982-1984 Eclipse of Epsilon Aurigae

International Nuclear Information System (INIS)

Stencel, R.E.

1985-09-01

A workshop proceedings concerned with the new data collected during the 1982-1984 eclipse period of the 27-year system Epsilon Aurigae is presented. This binary star has been a classic problem in astrophysics because the opaque eclipsing object is nonstellar, and probably disk shaped. Invited papers concerning the history of the system, optical, infrared and ultraviolet photometry, optical polarimetry and ultraviolet spectroscopy are included. An invited paper concerning comprehensive theoretical interpretation in the context of stellar evolution also is included

EFFECTIVENESS OF PNF STRETCHING AND CYCLIC STRETCHING OF CALF TIGHTNESS ON COLLEGE GOING GIRLS

Directory of Open Access Journals (Sweden)

Ashlesha Sirari

2015-06-01

Full Text Available Background: Flexibility helps with injury prevention, the reduction of soreness following a workout, and a general sense of well-being. There are different stretching techniques and protocols for improvements in calf extensibility and flexibility. The purpose of the study was to investigate the effectiveness of two techniques i.e. CYCLIC and PNF stretching which improves calf flexibility. This study was done to find the effectiveness of calf Cyclic and PNF stretching technique to improve calf flexibility. Methods: 30 subjects with age group 21-22 years were randomly allocated to 2 groups equally. Group 1(n=15 were given CYCLIC and group 2(n=15 were given PNF stretching technique. Plantar flexion was used to measure the calf tightness which was done before and after the treatment. Treatment was given for 7 days and on the 7th day the calf tightness was again measured. Results: The mean difference of the CYCLIC is 4.6 and mean difference of PNF is 4.7 which indicate that CYCLIC and PNF both are effective to improve calf flexibility but PNF is more effective than CYCLIC to improve calf flexibility. Conclusion: The neurophysiological basis of PNF, stating that the excitatory efficient of the neuromuscular spindle or the inhibitory afferent of the Golgi tendon organ (GTO or both are responsible for the effects. During PNF stretch and isometric contraction of stretched agonists for extended period may cause activation of its neuromuscular spindle. The increase in tension created during the isometric contraction of the pre – lengthened agonist contracts concentrically. Both the fascia & the spindle of the agonist adjust to the nearly lengthened position. These impulses travel via causing post synaptic inhibition of the motor neuron to agonist increasing the tension from the GTO. These impulses can override the impulses coming from the neuromuscular spindles arousing the muscle to reflexly resist to the change in length, thus helping in lengthening

The constitution and crystallography of thin thermal oxide layers on epsilon-Fesub2Nsub1-x

DEFF Research Database (Denmark)

Graat, Peter C.J.; Zandbergen, Henny W.; Somers, Marcel A. J.

2000-01-01

Oxide layers formed on epsilon-Fe2N1-x were investigated with X-ray photoelectron spectroscopy, X-ray diffraction, and in particular with high-resolution transmission electron microscopy. Prior to oxidation, the epsilon-Fe2N1-x substrates were either exposed to air at room temperature, or subject...

The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

LENUS (Irish Health Repository)

O'Sullivan, Kieran

2009-01-01

BACKGROUND: Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. METHODS: A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. RESULTS: Across both groups, there was a significant main effect for time (p < 0.001). PKE ROM significantly increased with warm-up (p < 0.001). From warm-up, PKE ROM further increased with static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p < 0.001) after 15 minutes of rest, but remained significantly greater than at baseline (p < 0.001). Between groups, there was no main effect for group (p = 0.462), with no difference in mean PKE ROM values at any individual stage of the protocol (p > 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). CONCLUSION: Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced

No muscle involvement in myoclonus-dystonia caused by epsilon-sarcoglycan gene mutations1

DEFF Research Database (Denmark)

Hjermind, L.E.; Vissing, J.; Asmus, F.

2008-01-01

Mutations in the epsilon-sarcoglycan gene (SGCE) can cause autosomal dominant inherited myoclonus-dystonia (M-D). Defects in other sarcoglycans; alpha-, beta-, gamma-, and delta can cause autosomal recessive inherited limb girdle muscular dystrophies. epsilon- and alpha-sarcoglycans are very...... strength and mass showed no difference between M-D patients and controls. Our findings indicate that patients with M-D have no signs or symptoms of muscle disease. This suggests a different role of the sarcoglycan complex epsilonbetagammadelta versus alphabetagammadelta complex in humans, as earlier...

Biodistribution and catabolism of {sup 18}F-labeled N-{epsilon}-fructoselysine as a model of Amadori products

Energy Technology Data Exchange (ETDEWEB)

Hultsch, Christina [Institute of Radiopharmacy, Research Center Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany); Hellwig, Michael [Institute of Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany); Pawelke, Beate [Institute of Radiopharmacy, Research Center Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany); Bergmann, Ralf [Institute of Radiopharmacy, Research Center Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany); Rode, Katrin [Institute of Radiopharmacy, Research Center Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany); Pietzsch, Jens [Institute of Radiopharmacy, Research Center Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany); Krause, Rene [Institute of Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany); Henle, Thomas [Institute of Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany)

2006-10-15

Amadori products are formed in the early stage of the so-called Maillard reaction between reducing sugars and amino acids or proteins. Such nonenzymatic glycosylation may occur during the heating or storage of foods, but also under physiological conditions. N-{epsilon}-fructoselysine is formed via this reaction between the {epsilon}-amino group of peptide-bound lysine and glucose. Despite the fact that, in certain heated foods, up to 50% of lysyl moieties may be modified to such lysine derivatives, up to now, very little is known about the metabolic fate of alimentary administered Amadori compounds. In the present study, N-succinimidyl-4-[{sup 18}F]fluorobenzoate was used to modify N-{epsilon}-fructoselysine at the {alpha}-amino group of the lysyl moiety. The in vitro stability of the resulting 4-[{sup 18}F]fluorobenzoylated derivative was tested in different tissue homogenates. Furthermore, the 4-[{sup 18}F]fluorobenzoylated N-{epsilon}-fructoselysine was used in positron emission tomography studies, as well as in studies concerning biodistribution and catabolism. The results show that the 4-[{sup 18}F]fluorobenzoylated N-{epsilon}-fructoselysine is phosphorylated in vitro, as well as in vivo. This phosphorylation is caused by fructosamine 3-kinases and occurs in vivo, particularly in the kidneys. Despite the action of these enzymes, it was shown that a large part of the intravenously applied radiolabeled N-{epsilon}-fructoselysine was excreted nearly unchanged in the urine. Therefore, it was concluded that the predominant part of peptide-bound lysine that was fructosylated during food processing is not available for nutrition.

VHH Activators and Inhibitors for Protein Kinase C Epsilon

NARCIS (Netherlands)

Summanen, M.M.I.

2012-01-01

Protein kinase C epsilon (PKCε), which is one of the novel PKC isozymes, is widely expressed throughout the body and has important roles in the function of the nervous, cardiovascular and immune systems. In order to better understand PKCε regulated pathways, isozyme specific activity modulators are

Acute Effects of Static vs. Ballistic Stretching on Strength and Muscular Fatigue Between Ballet Dancers and Resistance-Trained Women.

Science.gov (United States)

Lima, Camila D; Brown, Lee E; Wong, Megan A; Leyva, Whitney D; Pinto, Ronei S; Cadore, Eduardo L; Ruas, Cassio V

2016-11-01

Lima, CD, Brown, LE, Wong, MA, Leyva, WD, Pinto, RS, Cadore, EL, and Ruas, CV. Acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. J Strength Cond Res 30(11): 3220-3227, 2016-Stretching is used to increase joint range of motion, but the acute effects can decrease muscle strength. However, this may depend on the population or mode of stretching. The purpose of this study was to compare the acute effects of static vs. ballistic stretching on strength and muscular fatigue between ballet dancers and resistance-trained women. Fifteen resistance-trained women (age 23.8 ± 1.80 years, mass 67.47 ± 7.77 kg, height 168.30 ± 5.53 cm) and 12 ballet dancers (age 22.8 ± 3.04 years, mass 58.67 ± 5.65 kg, height 168.00 ± 7.69 cm) performed 5 days of testing. The first day was control (no stretching), whereas the other 4 days were static or ballistic stretching in a counterbalanced order. Range of motion, strength, and fatigue tests were also performed. Both groups demonstrated a significant decrease in hamstrings strength after static (102.71 ± 2.67 N·m) and ballistic stretching (99.49 ± 2.61 N·m) compared with control (113.059 ± 3.25 N·m), with no changes in quadriceps strength. For fatigue, only ballet dancers demonstrated a decrease from control (71.79 ± 4.88%) to ballistic (65.65 ± 8.19%), but no difference with static (65.01 ± 12.29%). These findings suggest that stretching decreases hamstrings strength similarly in ballet dancers and resistance-trained women, with no differences between modes of stretching. However, ballistic stretching only decreased muscular fatigue in ballet dancers, but not in resistance-trained women. Therefore, no stretching should be performed before strength performance. However, ballistic stretching may decrease acute muscular fatigue in ballet dancers.

MAGNETIC ACTIVITY CYCLES IN THE EXOPLANET HOST STAR {epsilon} ERIDANI

Energy Technology Data Exchange (ETDEWEB)

Metcalfe, T. S.; Mathur, S. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Buccino, A. P.; Mauas, P. J. D.; Petrucci, R. [Instituto de Astronomia y Fisica del Espacio (CONICET), C.C. 67 Sucursal 28, C1428EHA-Buenos Aires (Argentina); Brown, B. P. [Department of Astronomy and Center for Magnetic Self-Organization, University of Wisconsin, Madison, WI 53706-1582 (United States); Soderblom, D. R. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Henry, T. J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302 (United States); Hall, J. C. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2013-02-01

The active K2 dwarf {epsilon} Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in {epsilon} Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 {+-} 0.03 years and 12.7 {+-} 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called 'active' and 'inactive' sequences as proposed by Boehm-Vitense. Finally, based on the observed properties of {epsilon} Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

Acute effect of different stretching methods on flexibility and jumping performance in competitive artistic gymnasts.

Science.gov (United States)

Dallas, G; Smirniotou, A; Tsiganos, G; Tsopani, D; Di Cagno, A; Tsolakis, Ch

2014-12-01

The purpose of this study was to investigate the acute effects of 3 different warm up methods of stretching (static, proprioceptive neuromuscular facilitation, and stretching exercises on a Vibration platform) on flexibility and legs power-jumping performance in competitive artistic gymnasts. Eighteen competitive artistic gymnasts were recruited to participate in this study. Subjects were exposed to each of 3 experimental stretching conditions: static stretching (SS), proprioceptive neuromuscular facilitation stretching (PNF), and stretching exercises on a Vibration platform (S+V). Flexibility assessed with sit and reach test (S & R) and jumping performance with squat jump (SJ) and counter movement jump (CMJ) and were measured before, immediately after and 15 min after the interventions. Significant differences were observed for flexibility after all stretching conditions for S+V (+1.1%), SS (+5.7%) and PNF (+6.8%) (P=0.000), which remained higher 15 min after interventions (S+V (1.1%), SS (5.3%) and PNF (5.5%), respectively (P=0.000). PNF stretching increased flexibility in competitive gymnasts, while S+V maintained jumping performance when both methods were used as part of a warm-up procedure.

Measurements of the Fast Fission Factor ({epsilon}) in UO{sub 2}-Elements

Energy Technology Data Exchange (ETDEWEB)

Nylund, O

1961-03-15

These experiments were undertaken in order to check the {epsilon} - calculations for the R3/Adam reactor project and to obtain a more rigorous basis for calculations on fuel elements similar to the R3/Adam clusters. Different number of rods (19, 7, 1) and coolants (air, D{sub 2}O, H{sub 2}O) have been investigated. The measurements were performed in the central channel of the R1 research reactor making it possible also to study the influence due to adjacent R1 fuel rods. The method used (an activation technique) gives directly the relationship R between the fission rates in {sup 238}U and {sup 235}U . Knowing this quantity it is possible to compute {epsilon}. However, since {epsilon} is dependent on how it is defined, it is more convenient to use R in a comparison with calculated values. Calculations for some of the cases studied experimentally have been made according to a new heterogeneous method. The agreement between the calculated and measured R-values is relatively good, but there is a tendency for the latter to be somewhat higher, especially for the 19-rod element.

EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

Directory of Open Access Journals (Sweden)

Meena .V

2016-10-01

Full Text Available Background: Osteoarthritis (OA is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hold relax stretching versus static stretching on pain and flexibility of hamstrings following moist heat in knee osteoarthritis participants. Determining the effects of PNF Hold relax stretching versus Static stretching along with moist heat on pain and hamstring flexibility by VAS and Active knee extension range of motion in knee osteoarthritis individuals. Methods: 30 subjects with symptoms of knee osteoarthritis were randomly distributed into 2 groups 15 in each group. PNF Hold relax stretching along with moist heat is compared to Static stretching along with moist heat. Pain was measured by Visual Analogue Scale (VAS and hamstring flexibility by Active knee Extension Range of Motion (AKEROM by universal goniometer. Measurements are taken pre and post intervention. Results: The results indicated PNF Hold relax stretching along with moist heat showed a statistically significant improvement in pain (p<0.05 and improvement in hamstring flexibility (p<0.05 when compared to Static stretching along with moist heat. Conclusion: Subjects with PNF Hold relax stretching along with moist heat showed significant improvement in pain reduction and improving hamstring flexibility than Static stretching along with moist heat.

Endovascular rescue method for undesirably stretched coil.

Science.gov (United States)

Cho, Jae Hoon

2014-10-01

Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter.

Epsilon Systems on Geometric Crystals of type A_n

Directory of Open Access Journals (Sweden)

Toshiki Nakashima

2010-03-01

Full Text Available We introduce an epsilon system on a geometric crystal of type A_n, which is a certain set of rational functions with some nice properties. We shall show that it is equipped with a product structure and that it is invariant under the action of tropical R maps.

Stellar model chromospheres. IV - The formation of the H-epsilon feature in the sun /G2 V/ and Arcturus /K2 III/

Science.gov (United States)

Ayres, T. R.; Linsky, J. L.

1975-01-01

The formation of the Balmer-series member H-epsilon in the near-red wing of the Ca II H line is discussed for two cases: the sun (H-epsilon absorption profile) and Arcturus (H-epsilon emission profile). It is shown that although the H-epsilon source functions in both stars are dominated by the Balmer-continuum radiation field through photoionizations, the line-formation problems in the two stars are quantitatively different, owing to a substantial difference in the relative importance of the stellar chromosphere temperature inversion as compared with the stellar photosphere.

The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

Directory of Open Access Journals (Sweden)

Murray Elaine

2009-04-01

Full Text Available Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM. 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1 at baseline; (2 after warm-up; (3 after stretch (static or dynamic and (4 after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Results Across both groups, there was a significant main effect for time (p 0.05. Using ANCOVA to adjust for the non-significant (p = 0.141 baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05. Conclusion Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. Trial Registration ACTRN12608000638336

Acute Effect of Different Combined Stretching Methods on Acceleration and Speed in Soccer Players

Directory of Open Access Journals (Sweden)

Amiri-Khorasani Mohammadtaghi

2016-04-01

Full Text Available The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up, on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height: 177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49 years was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min stretching program (except for the no-stretching protocol, and 2 min rest periods, followed by the 10 and 20 m sprint test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic stretching compared with static, combined, and no-stretching protocols. There were also significant differences between the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more force for a faster execution.

Biodistribution and catabolism of 18F-labelled isopeptide N(epsilon)-(gamma-glutamyl)-L-lysine.

Science.gov (United States)

Hultsch, C; Bergmann, R; Pawelke, B; Pietzsch, J; Wuest, F; Johannsen, B; Henle, T

2005-12-01

Isopeptide bonds between the epsilon-amino group of lysine and the gamma-carboxamide group of glutamine are formed during strong heating of pure proteins or, more important, by enzymatic reaction mediated by transglutaminases. Despite the wide use of a microbial transglutaminase in food biotechnology, up to now little is known about the metabolic fate of the isopeptide N(epsilon)-(gamma-glutamyl)-L-lysine. In the present study, N-succinimidyl-4-[(18)F]fluorobenzoate was used to modify N(epsilon)-(gamma-glutamyl)-L-lysine at each of its two alpha-amino groups, resulting in the 4-[(18)F]fluorobenzoylated derivatives, for which biodistribution, catabolism, and elimination were investigated in male Wistar rats. A significant different biochemical behavior of the two labelled isopeptides was observed in terms of in vitro stability, in vivo metabolism as well as biodistribution. The results suggest that the metabolic fate of isopeptides is likely to be dependent on how they are reabsorbed - free or peptide bound.

ASTEROSEISMOLOGY OF THE NEARBY SN II PROGENITOR RIGEL. II. {epsilon}-MECHANISM TRIGGERING GRAVITY-MODE PULSATIONS?

Energy Technology Data Exchange (ETDEWEB)

Moravveji, Ehsan [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Moya, Andres [Departamento de Astrofisica, Centro de Astrobiologia (INTA-CSIC), P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Guinan, Edward F., E-mail: moravveji@iasbs.ac.ir [Department of Astronomy, Villanova University, 800 Lancaster Avenue, Villanova, PA (United States)

2012-04-10

The cores of luminous B- and A-type (BA) supergiant stars are the seeds of later core-collapse supernovae. Thus, constraining the near-core conditions in this class of stars can place tighter constraints on the size, mass, and chemical composition of supernova remnants. Asteroseismology of these massive stars is one possible approach into such investigations. Recently, Moravveji et al. in 2012 (hereafter Paper I) extracted 19 significant frequencies from a 6-year radial velocity monitoring of Rigel ({beta} Ori, B8 Ia). The periods they determined broadly range from 1.22 to 74.74 days. Based on our differentially rotating stellar structure and evolution model, Rigel, at its current evolutionary state, is undergoing core He burning and shell H burning. Linear fully non-adiabatic non-radial stability analyses result in the excitation of a dense spectrum of non-radial gravity-dominated mixed modes. The fundamental radial mode (l = 0) and its overtones are all stable. When the hydrogen-burning shell is located even partially in the radiative zone, a favorable condition for destabilization of g-modes through the so-called {epsilon}-mechanism becomes viable. Only those g-modes that have high relative amplitudes in the hydrogen-burning (radiative) zone can survive the strong radiative damping. From the entire observed range of variability periods of Rigel (found in Paper I), and based on our model, only those modes with periods ranging between 21 and 127 days can be theoretically explained by the {epsilon}-mechanism. The origin of the short-period variations (found in Paper I) still remains unexplained. Because Rigel is similar to other massive BA supergiants, we believe that the {epsilon}-mechanism may be able to explain the long-period variations in {alpha} Cygni class of pulsating stars.

Biaxial stretching of film principles and applications

CERN Document Server

Demeuse, M T

2011-01-01

Biaxial (having two axes) stretching of film is used for a range of applications and is the primary manufacturing process by which products are produced for the food packaging industry. Biaxial stretching of film: principles and applications provides an overview of the manufacturing processes and range of applications for biaxially stretched films. Part one reviews the fundamental principles of biaxial stretching. After an introductory chapter which defines terms, chapters discuss equipment design and requirements, laboratory evaluations, biaxial film structures and typical industrial processes for the biaxial orientation of films. Additional topics include post production processing of biaxially stretched films, the stress-strain behaviour of poly(ethylene terephthalate) and academic investigations of biaxially stretched films. Part two investigates the applications of biaxial films including fresh cut produce, snack packaging and product labelling. A final chapter investigates potential future trends for bi...

The O(epsilon2) scaling law for dsigma/dt in the Reggeon field theory

International Nuclear Information System (INIS)

Dash, J.W.; Grandou, Thierry.

1979-04-01

The two loop contributions were calculated within the epsilon-expansion to the Reggeon Field Theory scaling law for dsigma/dt, derived using the renormalization group and a general renormalization point for the Pomeron propagator. This generalizes the O(epsilon) work of Abarbanel, Bartels, Bronzan, and Sidhu. The invariance of the results under certain coupling constant rescalings is demonstrated. Some qualitative comments were made regarding phenomenological applications. Our amplitude in a certain limit approximates the form of the low energy diffractive amplitude advocated by Kane

Effect of hexane treatment and uniaxial stretching on bending ...

African Journals Online (AJOL)

PVDF) film was studied. The quantity, β31, defined as the bending piezoelectric stress constant, was calculated. After hexane treatment and uniaxial stretching of the PVDF film, the value of β31 was 5.75 mV/m and 8.00 mV/m for draw ratio of ...

Mouse splenic and bone marrow cell populations that express high-affinity Fc epsilon receptors and produce interleukin 4 are highly enriched in basophils.

OpenAIRE

Seder, R A; Paul, W E; Dvorak, A M; Sharkis, S J; Kagey-Sobotka, A; Niv, Y; Finkelman, F D; Barbieri, S A; Galli, S J; Plaut, M

1991-01-01

Splenic and bone marrow cells from normal mice, and from mice that have been polyclonally activated by injection of anti-IgD antibody, contain cells that produce interleukin 4 (IL-4) in response to crosslinkage of Fc epsilon receptors (Fc epsilon R) or Fc gamma R or to ionomycin. Isolated Fc epsilon R+ cells have recently been shown to contain all of the IL-4-producing capacity of the nonlymphoid compartment of spleen and bone marrow. Here, purified Fc epsilon R+ cells are shown to be enriche...

Epsilon Aurigae

Science.gov (United States)

Turner, Rebecca; Price, A.; Henden, A.

2009-05-01

The IYA 2009 working group on Research Experiences for Students, Teachers, and Citizen-Scientists is planning a multi-year project involving the bright star Eps Aur. The project will go beyond simple observing and also include a major data analysis component. The goal is to introduce the participant to the full scientific process from background research to paper writing for a peer-reviewed journal. It begins with a 10 Star Training Program of several types of binary and transient variable stars that are easy to observe from suburban locations with the naked eye. Participants will be trained both in observing and also in basic data analysis of photometric datasets (light curve and period analysis). Eventually it will lead to a capstone project: monitoring the rare and mysterious 2009-2011 eclipse of Epsilon Aurigae. In the summer of IYA 2009, third-magnitude Eps Aur will experience its next eclipse, which occurs every 27.1 years and lasts 714 days, nearly two years. The star is bright enough to be seen with the naked eye from most urban areas. If fully funded, the project will also involve two public workshops on observing and data analysis in the summers of 2009 and 2010, respectively.

Precipitation of Epsilon Copper in Ferrite Antibacterial Stainless Steel

Institute of Scientific and Technical Information of China (English)

Zhixia ZHANG; Gang LIN; Zhou XU

2008-01-01

The precipitation of epsilon copper at 1023 K ageing in ferrite antibacterial stainless steel was investigated by a combination of electron microscopy and micro-Vickers hardness measurement. The results show that epsilon copper precipitation occurs within 90 s. Complex rnultilayer structure confirmed as twins and stacking faults on {111}ε-Cu planes was observed in the precipitates. The precipitates grow by the lengthwise enlargement of a set of parallel layers, having [111]ε-Cu and [112]ε-Cu preferred growth orientations. The volume fraction of precipitates f formed within 120 min can be predicted by a modified Avrami equation (In 1/1-f= kt+b).Simultaneously, substituent atom clusters with a size of 5-10 nm was found to occur in the solution and cause matrix strain. The precipitate morphology and distribution on the surface of ferrite antibacterial stainlesss teel are associated with surface crystallographic orientation of the matrix. The precipitates are predominantly located within the ferrite grains of orientation. The precipitates located on {111}α-Fe surface planes have sphere or ellipse shape.

Correlation between structure and conductivity in stretched Nafion

Science.gov (United States)

Allahyarov, Elshad; Taylor, Philip

2008-03-01

We have used coarse-grained simulation methods to investigate the effect of stretching-induced structure orientation on the proton conductivity of Nafion-like polyelectrolyte membranes. Recent experimental data on the morphology of ionomers describe Nafion as an aggregation of polymeric backbone chains forming elongated objects embedded in a continuous ionic medium. Uniaxial stretching of a recast Nafion film causes a preferential orientation of these objects in the direction of stretching. Our simulations of humid Nafion show that this has a strong effect on the proton conductivity, which is enhanced along the stretching direction, while the conductivity perpendicular to the stretched polymer backbone is strongly reduced. Stretching also causes the perfluorinated side chains to orient perpendicular to the stretching axis. The sulphonate multiplets shrink in diameter as the stretching is increased and show a spatially periodic ordering in their distribution. This in turn affects the distribution of contained water at low water contents. The water forms a continuous network with narrow bridges between small water clusters absorbed in head-group multiplets. We find the morphological changes in the stretched Nafion to be retained upon removal of the uniaxial stress.

Kinetics of epsilon antitoxin antibodies in different strategies for active immunization of lambs against enterotoxaemia

Directory of Open Access Journals (Sweden)

Heni F. Costa

2013-08-01

Full Text Available Enterotoxaemia, a common disease that affects domestic small ruminants, is mainly caused by the epsilon toxin of Clostridium perfringens type D. The present study tested four distinct immunization protocols to evaluate humoral response in lambs, a progeny of non-vaccinated sheep during gestation. Twenty-four lambs were randomly allocated into four groups according to age (7, 15, 30 and 45 days, receiving the first dose of epsilon toxoid commercial vaccine against clostridiosis with booster after 30 days post vaccination. Indirect ELISA was performed after the first vaccine dose and booster to evaluate the immune response of the lambs. Results showed that for the four protocols tested all lambs presented serum title considered protective (≥0.2UI/ml epsilon antitoxin antibodies and also showed that the anticipation of primovaccination of lambs against enterotoxaemia conferred serum title considered protective allowing the optimization of mass vaccination of lambs.

Characterization of mechanical behavior of a porcine pulmonary artery strip using a randomized uniaxial stretch and stretch-rate protocol

Directory of Open Access Journals (Sweden)

Criscione John C

2008-01-01

Full Text Available Abstract Background Much of the experimental work in soft tissue mechanics has been focused on fitting approximate relations for specific tissue types from aggregate data on multiple samples of the tissue. Such relations are needed for modeling applications and have reasonable predictability – especially given the natural variance in specimens. There is, however, much theoretical and experimental work to be done in determining constitutive behaviors for particular specimens and tissues. In so doing, it may be possible to exploit the natural variation in tissue ultrastructure – so to relate ultrastructure composition to tissue behavior. Thus, this study focuses on an experimental method for determining constitutive behaviors and illustrates the method with analysis of a porcine pulmonary artery strip. The method characterizes the elastic part of the response (implicitly in terms of stretch and the inelastic part in terms of short term stretch history (i.e., stretch-rate Ht2, longer term stretch history Ht1, and time since the start of testing T. Methods A uniaxial testing protocol with a random stretch and random stretch-rate was developed. The average stress at a particular stretch was chosen as the hyperelastic stress response, and deviation from the mean at this particular stretch is chosen as the inelastic deviation. Multivariable Linear Regression Analysis (MLRA was utilized to verify if Ht2, Ht1, and T are important factors for characterizing the inelastic deviation. For acquiring Ht2 and Ht1, an integral function type of stretch history was employed with time constants chosen from the relaxation spectrum of an identical size strip from the same tissue with the same orientation. Finally, statistical models that characterize the inelasticity were developed at various, nominal values of stretch, and their predictive capability was examined. Results Inelastic deviation from hyperelasticity was high (31% for low stretch and declined

{epsilon}-Caprolactam migration from irradiated PA-6 food packaging: kinetic simulation and measurement

Energy Technology Data Exchange (ETDEWEB)

Rosa, Faena Machado Leite [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Felix, Juliana; Araujo, Henrique Peres; Monteiro, Magali [UNESP, Araraquara, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Alimentos e Nutricao; Padula, Marisa [Instituto de Tecnologia de Alimentos (ITAL), Campinas, SP (Brazil). Centro de Tecnologia de Embalagem; Manzoli, Jose Eduardo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade Sao Judas Tadeu (USJT), Sao Paulo, SP (Brazil)], E-mail: jmanzoli@ipen.br

2007-07-01

Migration of low molecular mass compounds (LMMC), such as monomers and additives, from plastic packaging into food simulants is a very important issue, concerning public health and chemical contamination of foods. Sterilization of food packaging materials with ionizing radiation is considered an alternative to other sterilization methods, but when polymers are irradiated, LMMC may be formed, as radiolysis products. According to the Brazilian legislation, specific migration tests, such as those of LMMC from packaging into simulants, should be carried out at certain temperature and time, depending on the real conditions of contact. In this work, multilayer flexible films with polyamide 6 (PA-6), used for meat foodstuffs, were studied. The {epsilon}-caprolactam (PA-6 monomer) specific migration into acetic acid 3% simulant at 40 deg C during 10 days and at 100 deg C during 30 minutes was performed. The initial monomer level in the irradiated and non irradiated PA-6 films was quantified by high resolution gas chromatography (HRGC). Radiation doses were 3 and 7 kGy. {epsilon}-caprolactam specific migration was carried out only with non irradiated films. The results showed that radiation causes a significant change in the monomer level, up or down, depending on the multilayer film type. The kinetic of the {epsilon}-caprolactam migration at both temperatures, 40 and 100 deg C was clearly explained by the numerical simulation, combining an Arrhenius equation with the Fick's second law, although this kinetic was not experimentally studied. This simulation allowed to predict diffusion parameters estimates, like diffusion coefficients and activation energies of {epsilon}-caprolactam in the films or simulant. (author)

Stretch-dependent slow force response in isolated rabbit myocardium is Na+ dependent.

Science.gov (United States)

von Lewinski, Dirk; Stumme, Burkhard; Maier, Lars S; Luers, Claus; Bers, Donald M; Pieske, Burkert

2003-03-15

Stretch induces functional and trophic effects in mammalian myocardium via various signal transduction pathways. We tested stretch signal transduction on immediate and slow force response (SFR) in rabbit myocardium. Experiments were performed in isolated right ventricular muscles from adult rabbit hearts (37 degrees C, 1 Hz stimulation rate, bicarbonate-buffer). Muscles were rapidly stretched from 88% of optimal length (L88) to near optimal length (L98) for functional analysis. The resulting immediate and slow increases in twitch force (first phase and SFR, respectively) were assessed at reduced [Na+]o or without and with blockade of stretch activated ion channels (SACs), angiotensin-II (AT1) receptors, endothelin-A (ET(A)) receptors, Na+/H+-exchange (NHE1), reverse mode Na+/Ca2+-exchange (NCX), or Na+/K+-ATPase. The effects of stretch on sarcoplasmic reticulum Ca2+-load were characterized using rapid cooling contractures (RCCs). Intracellular pH was measured in BCECF-AM loaded muscles, and action potential duration (APD) was assessed using floating electrodes. On average, force increased to 216+/-8% of the pre-stretch value during the immediate phase, followed by a further increase to 273+/-10% during the SFR (n=81). RCCs significantly increased during SFR, whereas pH and APD did not change. Neither inhibition of SACs, AT1, or ET(A) receptors affected the stretch-dependent immediate phase nor SFR. In contrast, SFR was reduced by NHE inhibition and almost completely abolished by reduced [Na+]o or inhibition of reverse-mode NCX, whereas increased SFR was seen after raising [Na+]i by Na+/K+-ATPase inhibition. The data demonstrate the existence of a delayed, Na+- and Ca2+-dependent but pH and APD independent SFR to stretch in rabbit myocardium. This inotropic response appears to be independent of autocrine/paracrine AT1 or ET(A) receptor activation, but mediated through stretch-induced activation of NHE and reverse mode NCX.

Coherent production of {epsilon}{sup +} particles in crystal using proton beam from SSC

Energy Technology Data Exchange (ETDEWEB)

Okorokov, V.V.; Dubin, A.Yu. [ITER, Moscow, (Russian Federation)

1995-05-01

The unique possibilities of the SSC can be ideally used for a new generation of coherent generation experiments with relativistic protons which require 20 Tev energy of the incident beam. The availability of 20 Tev proton beam at SSC allows new experiments on coherent production of {var_epsilon}{sup +} particle by relativistic proton in crystal. Experiment carried out at low energies can now be extended with protons in very narrow energy region (resonance energy, which easy can be calculated) using the new accelerator facilities at SSC. We propose to study coherent production via the Coulomb field of the cristal atoms to excite the transition p + {gamma}{implies} {var_epsilon} {sup +} (1189).

Increased mental slowing associated with the APOE epsilon4 allele after trihexyphenidyl oral anticholinergic challenge in healthy elderly.

Science.gov (United States)

Pomara, Nunzio; Belzer, Ken; Hernando, Raymundo; De La Pena, Corazon; Sidtis, John J

2008-02-01

The objectives of this study were to examine the relationship between APOE epsilon4 and subjective effects of trihexyphenidyl on measures reflecting sedation and confusion and to investigate the relationship between trihexyphenidyl-induced subjective effects and objective memory performance. This study comprised 24 cognitively intact, health elderly adults (12 APOE epsilon4 carriers) at an outpatient geriatric psychiatry research clinic. This was a randomized, double blind, placebo-controlled, three-way, crossover experimental design. All participants received 1.0 mg or 2.0 mg trihexyphenidyl or placebo administered in counterbalanced sequences over a period of three consecutive weeks. Bond and Lader's visual analog scales and alternate versions of the Buschke Selective Reminding Test were administered in a repeated measures design at baseline, 1, 2.5, and 5 hours postdrug administration. A 2.0-mg oral dose of trihexyphenidyl resulted in increased subjective ratings of mental slowness in carriers of the APOE epsilon4 allele only. Drug effects as determined by difference scores between 2.0 mg trihexyphenidyl and placebo on ratings of mental slowness significantly correlated with total and delayed recall on the Buschke Selective Reminding Test in carriers of the APOE epsilon4 allele only. However, no significant effects were found with other visual analog scales reflecting subjective sedation and clear-headedness. The epsilon4 allele in healthy elderly was associated with increased subjective mental slowing after trihexyphenidyl anticholinergic challenge.

An Analysis of the Long-term Photometric Behavior of epsilon Aurigae

Science.gov (United States)

Kloppenborg, B. K.; Hopkins, J. L.; Stencel, R. E.

2012-10-01

The lure of a 50% reduction in light has brought a multitude of observers and researchers to epsilon Aur every twenty-seven years, but few have paid attention to the system outside of eclipse. As early as the late 1800s, it was clear that the system undergoes some form of quasi-periodic variation outside of totality, but few considered this effect in their research until the mid-1950s. In this work we focus exclusively on the out-of-eclipse (OOE) variations seen in this system. We have digitized twenty-seven sources of historic photometry from eighty-one different observers. Two of these sources provide twenty-seven years of inter-eclipse UBV photometry which we have analyzed using modern period finding techniques. We have discovered the F-star variations are multi-periodic with at least two periods that evolve in time at DP ≈ -1.5 day/year. These periods are detected when they manifest as near-sinusoidal variations at 3,200-day intervals. We discuss our work in an evolutionary context by comparing the behavior found in epsilon Aur with bona-fide supergiant and post-AGB stars of similar spectral type. Based upon our qualitative comparison, we find the photometric behavior of the F-star in the epsilon Aur system is more indicative of supergiant behavior. Therefore the star is more likely to be a "traditional supergiant" than a post-AGB object. We encourage continued photometric monitoring of this system to test our predictions.

Effectiveness of Plantar Fascia-Specific Stretching Exercises in Plantar Fasciitis

Directory of Open Access Journals (Sweden)

Devrim Özer

2015-12-01

Full Text Available Aim: Plantar fasciitis (PF is a painful and disabling disease that affects the quality of life and daily activities of patients and it is the most common cause of heel pain in adults. In primary treatment, conservative treatment is suggested and different conservative options are described in the literature. In our study, we evaluated the efficacy of plantar fascia-specific stretching exercises in the treatment of PF. Methods: Twenty-nine feet - 21 patients with the mean age of 49.3 years were included in the study. The mean length of follow-up was 19.8 months and the mean length of exercise period was 4.94 months. Non-weight bearing plantar fascia-specific stretching exercise was done twice daily, for 10 times at each session. In addition to exercises, silicone heel pad and nonsteroidal anti-inflammatory drugs (NSAID were added. Visual analog scale (VAS was used for pain evaluation. Results: Full recovery detected in 15 feet in 10 patients (52% and a decrease in pain was seen in 10 feet in 8 patients (34%. There was no response in 4 feet in 3 patients (14%. There was statistically significant difference between pre-treatment and post-treatment visual analog scale scores (p=0.0001. Conclusion: Plantar fascia-specific stretching exercise is an effective treatment option in PF.

Epsilon-Q: An Automated Analyzer Interface for Mass Spectral Library Search and Label-Free Protein Quantification.

Science.gov (United States)

Cho, Jin-Young; Lee, Hyoung-Joo; Jeong, Seul-Ki; Paik, Young-Ki

2017-12-01

Mass spectrometry (MS) is a widely used proteome analysis tool for biomedical science. In an MS-based bottom-up proteomic approach to protein identification, sequence database (DB) searching has been routinely used because of its simplicity and convenience. However, searching a sequence DB with multiple variable modification options can increase processing time, false-positive errors in large and complicated MS data sets. Spectral library searching is an alternative solution, avoiding the limitations of sequence DB searching and allowing the detection of more peptides with high sensitivity. Unfortunately, this technique has less proteome coverage, resulting in limitations in the detection of novel and whole peptide sequences in biological samples. To solve these problems, we previously developed the "Combo-Spec Search" method, which uses manually multiple references and simulated spectral library searching to analyze whole proteomes in a biological sample. In this study, we have developed a new analytical interface tool called "Epsilon-Q" to enhance the functions of both the Combo-Spec Search method and label-free protein quantification. Epsilon-Q performs automatically multiple spectral library searching, class-specific false-discovery rate control, and result integration. It has a user-friendly graphical interface and demonstrates good performance in identifying and quantifying proteins by supporting standard MS data formats and spectrum-to-spectrum matching powered by SpectraST. Furthermore, when the Epsilon-Q interface is combined with the Combo-Spec search method, called the Epsilon-Q system, it shows a synergistic function by outperforming other sequence DB search engines for identifying and quantifying low-abundance proteins in biological samples. The Epsilon-Q system can be a versatile tool for comparative proteome analysis based on multiple spectral libraries and label-free quantification.

Stretched polygons in a lattice tube

Energy Technology Data Exchange (ETDEWEB)

Atapour, M [Department of Mathematics and Statistics, York University, Toronto, ON M3J 1P3 (Canada); Soteros, C E [Department of Mathematics and Statistics, University of Saskatchewan, Saskatoon, SK S7N 5E6 (Canada); Whittington, S G [Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6 (Canada)], E-mail: atapour@mathstat.yorku.ca, E-mail: soteros@math.usask.ca, E-mail: swhittin@chem.utoronto.ca

2009-08-14

We examine the topological entanglements of polygons confined to a lattice tube and under the influence of an external tensile force f. The existence of the limiting free energy for these so-called stretched polygons is proved and then, using transfer matrix arguments, a pattern theorem for stretched polygons is proved. Note that the tube constraint allows us to prove a pattern theorem for any arbitrary value of f, while without the tube constraint it has so far only been proved for large values of f. The stretched polygon pattern theorem is used first to show that the average span per edge of a randomly chosen n-edge stretched polygon approaches a positive value, non-decreasing in f, as n {yields} {infinity}. We then show that the knotting probability of an n-edge stretched polygon confined to a tube goes to one exponentially as n {yields} {infinity}. Thus as n {yields} {infinity} when polygons are influenced by a force f, no matter its strength or direction, topological entanglements, as defined by knotting, occur with high probability. (fast track communication)

Stretched polygons in a lattice tube

International Nuclear Information System (INIS)

Atapour, M; Soteros, C E; Whittington, S G

2009-01-01

We examine the topological entanglements of polygons confined to a lattice tube and under the influence of an external tensile force f. The existence of the limiting free energy for these so-called stretched polygons is proved and then, using transfer matrix arguments, a pattern theorem for stretched polygons is proved. Note that the tube constraint allows us to prove a pattern theorem for any arbitrary value of f, while without the tube constraint it has so far only been proved for large values of f. The stretched polygon pattern theorem is used first to show that the average span per edge of a randomly chosen n-edge stretched polygon approaches a positive value, non-decreasing in f, as n → ∞. We then show that the knotting probability of an n-edge stretched polygon confined to a tube goes to one exponentially as n → ∞. Thus as n → ∞ when polygons are influenced by a force f, no matter its strength or direction, topological entanglements, as defined by knotting, occur with high probability. (fast track communication)

Elastography Study of Hamstring Behaviors during Passive Stretching.

Directory of Open Access Journals (Sweden)

Guillaume Le Sant

Full Text Available The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography.The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%, semimembranosus (SM, CV: 10.3%-11.2% and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%, but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%. Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh.This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury.

Elastography Study of Hamstring Behaviors during Passive Stretching

Science.gov (United States)

Le Sant, Guillaume; Ates, Filiz; Brasseur, Jean-Louis; Nordez, Antoine

2015-01-01

Introduction The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography. Methods/Results The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion) on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%), semimembranosus (SM, CV: 10.3%-11.2%) and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%), but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%). Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh. Conclusion This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury. PMID:26418862

Gelatinized and nongelatinized corn starch/ poly(epsilon-caprolactone) blends: characterization by rheological, mechanical and morphological properties

OpenAIRE

Rosa,Derval S.; Guedes,Cristina G. F.; Pedroso,Andréa G.

2004-01-01

Poly(epsilon-caprolactone)/corn starch blends containing 25, 50 and 75 wt.% starch were prepared by mechanical processing and characterized by the melt flow index (MFI), tensile test and scanning electron microscopy (SEM). For comparison, starch was used in gelatinized and nongelatinized forms and was also characterized by viscography. The addition of starch to poly(epsilon-caprolactone) reduced the MFI values, the tensile strength and the elongation at break, whereas the modulus increased. T...

The NH2-terminal php domain of the alpha subunit of the Escherichia coli replicase binds the epsilon proofreading subunit.

Science.gov (United States)

Wieczorek, Anna; McHenry, Charles S

2006-05-05

The alpha subunit of the replicase of all bacteria contains a php domain, initially identified by its similarity to histidinol phosphatase but of otherwise unknown function (Aravind, L., and Koonin, E. V. (1998) Nucleic Acids Res. 26, 3746-3752). Deletion of 60 residues from the NH2 terminus of the alpha php domain destroys epsilon binding. The minimal 255-residue php domain, estimated by sequence alignment with homolog YcdX, is insufficient for epsilon binding. However, a 320-residue segment including sequences that immediately precede the polymerase domain binds epsilon with the same affinity as the 1160-residue full-length alpha subunit. A subset of mutations of a conserved acidic residue (Asp43 in Escherichia coli alpha) present in the php domain of all bacterial replicases resulted in defects in epsilon binding. Using sequence alignments, we show that the prototypical gram+ Pol C, which contains the polymerase and proofreading activities within the same polypeptide chain, has an epsilon-like sequence inserted in a surface loop near the center of the homologous YcdX protein. These findings suggest that the php domain serves as a platform to enable coordination of proofreading and polymerase activities during chromosomal replication.

The acute effects of stretching with vibration on dynamic flexibility in young female gymnasts.

Science.gov (United States)

Johnson, Aaron W; Warcup, Caisa N; Seeley, Matthew K; Eggett, Dennis; Feland, Jeffery B

2018-01-10

While stretching with vibration has been shown to improve static flexibility; the effect of stretching with vibration on dynamic flexibility is not well known. The purpose of this study was to examine the effectiveness of stretching with vibration on acute dynamic flexibility and jump height in novice and advanced competitive female gymnasts during a split jump. Female gymnast (n=27, age: 11.5 ± 1.7 years, Junior Olympic levels 5-10) participated in this cross-over study. Dynamic flexibility during gymnastic split jumps were video recorded and analyzed with Dartfish software. All participants completed both randomized stretching protocols with either the vibration platform turned on (VIB) (frequency of 30 Hz and 2 mm amplitude) or off (NoVIB) separated by 48 h. Participants performed 4 sets of three stretches on the vibration platform. Each stretch was held for 30 s with 5 s rest for a total of 7 min of stretch. Split jump flexibility decreased significantly from pre to post measurement in both VIB (-5.8°±5.9°) (p<0.001) and NoVIB (-2.6°±6.1°) (p=0.041) conditions (adjusted for gymnast level). This effect was greatest in lower skill level gymnasts (p=0.003), while the highest skill level gymnasts showed no significant decrease in the split jump (p=0.105). Jump height was not significantly different between conditions (p=0.892) or within groups (p=0.880). An acute session of static stretching with or without vibration immediately before performance does not alter jump height. Stretching with vibration immediately prior to gymnastics competition decreases split jump flexibility in lower level gymnasts more than upper level gymnasts.

The efficiency of subset selection of an epsilon-best uniform population relative to selection of the best one

NARCIS (Netherlands)

Laan, van der P.

1993-01-01

Assume k (\\geq 2) uniform populations are given on (\\mu_i - ½, \\mu_i + ½) with location parameter \\mu_i \\in R^1, i = 1, ..., k. The best population is defined as the population with the largest value of the location parameter. In \\epsilon-best population (with \\epsilon \\geq 0) is a population with

MIMO scheme performance and detection in epsilon noise

OpenAIRE

Stepanov, Sander

2006-01-01

New approach for analysis and decoding MIMO signaling is developed for usual model of nongaussion noise consists of background and impulsive noise named epsilon - noise. It is shown that non-gaussion noise performance significantly worse than gaussion ones. Stimulation results strengthen out theory. Robust in statistical sense detection rule is suggested for such kind of noise features much best robust detector performance than detector designed for Gaussian noise in impulsive environment and...

Stretch Marks

Science.gov (United States)

... completely without the help of a dermatologist or plastic surgeon. These doctors may use one of many types of treatments — from actual surgery to techniques like microdermabrasion and laser treatment — to reduce the appearance of stretch marks. These techniques are ...

Peripheral nerve regeneration through P(DLLA-epsilon-CL) nerve guides

NARCIS (Netherlands)

Den Dunnen, WFA; Meek, MF; Robinson, PH; Schakernraad, JM

1998-01-01

P(DLLA-epsilon-CL) nerve guides can be used perfectly for short nerve gaps in rats, and are even better than short autologous nerve grafts. The tube dimensions, such as the internal diameter and wall thickness, are very important for the final outcome of peripheral nerve regeneration, as well as the

The effects of ramp stretches on active contractions in intact mammalian fast and slow muscle fibres.

Science.gov (United States)

Mutungi, G; Ranatunga, K W

2001-01-01

The effects of a ramp stretch (amplitude muscle fibre length (L0), speed twitch tension and twitch tension re-development were examined in intact mammalian (rat) fast and slow muscle fibre bundles. The experiments were done in vitro at 20 degrees C and at an initial sarcomere length of 2.68 microm. In both fibre types, a stretch applied during the rising phase of the twitch response (including the time of stimulation) increased the re-developed twitch tension (15-35%). A stretch applied before the stimulus had little or no effect on the twitch myogram in fast muscle fibres, but it increased the twitch tension (approximately 5%) in slow muscle fibres. A similar stretch had little or no effect on tetanic tension in either muscle fibre type. In general, the results indicate that the contractile-activation mechanism may be stretch sensitive and this is particularly pronounced in slow muscle fibres. Recorded at a high sampling rate and examined at an appropriate time scale, the transitory tension response to a stretch rose in at least two phases; an initial rapid tension rise to a break (break point tension, P1a) followed by a slower tension rise (apparent P2a) to a peak reached at the end of the stretch. Plotted against stretch velocity, P1a tension increased in direct proportion to stretch velocity (viscous-like) whereas, P2a tension (calculated as peak tension minus P1a tension) increased with stretch velocity to a plateau (visco-elastic). Examined at the peak of a twitch, P1a tension had a slope (viscosity coefficient) of 1.8 kN m(-2) per L0 s(-1) in fast fibres and 4.7 kN m(-2) per L0 s(-1) in slow muscle fibres. In the same preparations, P2a tension had a relaxation time of 8 ms in the fast muscle fibres and 25 ms in the slow muscle fibres. The amplitudes of both tension components scaled with the instantaneous twitch tension in qualitatively the same way as the instantaneous fibre stiffness. These fast/slow fibre type differences probably reflect differences in

Ultraviolet Flux Variation of Epsilon Aurigae

Directory of Open Access Journals (Sweden)

Young Woon Kang

1990-06-01

Full Text Available The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 Å to 3050 Å. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

Application of a k-epsilon closure to a heated turbulent offset jet

International Nuclear Information System (INIS)

Raghunath, G.; Kumar, R.; Liburdy, J.A.

1986-01-01

The complex flow which occurs when a heated turbulent jet discharges above a cool, isothermal surface was investigated numerically. This flow is influenced by significant flow curvature, buoyancy, impingement, and recirculation. The main features of the flow have been characterized in the literature by the exit Reynolds number and offset ratio. It is the purpose of this study to assess the applicability of a modified k-epsilon closure model to this flow. Comparisons with limited data for the unheated case and flow predictions for the heated case are presented. The impingement distance is determined to within 2 percent of the experimental results. However, detailed velocity profiles are not well predicted near the wall. Curvature modification and the wall boundary condition for epsilon significantly affect the solution. 15 references

Analysis of dependence of fission cross section and angular anisotropy of the 235U fission fragment escape induced by neutrons of intermediate energies (epsilon < or approximately200 keV) on target nucleus orientation

International Nuclear Information System (INIS)

Barabanov, A.L.

1985-01-01

Experimental data on dependence of fission cross section Σsub(f) (epsilon) and angular anisotropy W(epsilon, 0 deg)/W(epsilon, 90 deg) of sup(235)U fission fragment escape by neutrons with energy epsilon=100 and 200 keV on orientation of target nuclei are analyzed. 235 U (Isup(πsub(0))=7/2sup(-)) nuclei were orientated at the expense of interaction of quadrupole nucleus momenta with nonuniform electric field of uranyl-rubidium nitrate crystal at crystal cooling to T=0.2 K. The analysis was carried out with three different sets of permeability factors T(epsilon). Results of the analysis weakly depend on T(epsilon) choice. It is shown that a large number of adjusting parameters (six fissionabilities γsup(f)(Jsup(π), epsilon) and six momenta sub(Jsup(π))) permit to described experimental data on Σsub(f)(epsilon) and W(epsilon, 0 deg)/W(epsilon, 90 deg), obtained at epsilon=200 keV by introducing essential dependence of γsup(f)(Jsup(π), epsilon) and sub(Jsup(π)) on Jsup(π). Estimations of fission cross sections Σsub(f)(epsilon) and angular distribution W(epsilon, n vector) up to T approximately equal to 0.01 K in two geometries of the experiment: the orientation axis is parallel and perpendicular to momentum direction p vector of incident neutrons, are conducted

Effects of contract-relax vs static stretching on stretch-induced strength loss and length-tension relationship

DEFF Research Database (Denmark)

Balle, S S; Magnusson, S P; McHugh, M P

2015-01-01

The purpose of this study was to determine the acute effects of contract-relax stretching (CRS) vs static stretching (SS) on strength loss and the length-tension relationship. We hypothesized that there would be a greater muscle length-specific effect of CRS vs SS. Isometric hamstring strength wa...

Bias of purine stretches in sequenced chromosomes

DEFF Research Database (Denmark)

Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

2002-01-01

/pur tracts was slightly less than expected, with an average of 0.8%. One of the most surprising findings is a clear difference in the length distributions of the regions studied between prokaryotes and eukaryotes. Whereas short-range correlations can explain the length distributions in prokaryotes......, in eukaryotes there is an abundance of long stretches of purines or alternating purine/pyrimidine tracts, which cannot be explained in this way; these sequences are likely to play an important role in eukaryotic chromosome organisation....

A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics.

Science.gov (United States)

Weise, Louis D; Panfilov, Alexander V

2013-01-01

We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006) and tension development (adjusted Niederer, Hunter, Smith, 2006 model) with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material). Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.

A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics.

Directory of Open Access Journals (Sweden)

Louis D Weise

Full Text Available We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006 and tension development (adjusted Niederer, Hunter, Smith, 2006 model with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material. Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.

Stretching and jamming of finite automata

NARCIS (Netherlands)

Beijer, de N.; Kourie, D.G.; Watson, B.W.; Cleophas, L.G.W.A.; Watson, B.W.

2004-01-01

In this paper we present two transformations on automata, called stretching and jamming. These transformations will, under certain conditions, reduce the size of the transition table, and under other conditions reduce the string processing time. Given a finite automaton, we can stretch it by

High throughput web inspection system using time-stretch real-time imaging

Science.gov (United States)

Kim, Chanju

Photonic time-stretch is a novel technology that enables capturing of fast, rare and non-repetitive events. Therefore, it operates in real-time with ability to record over long period of time while having fine temporal resolution. The powerful property of photonic time-stretch has already been employed in various fields of application such as analog-to-digital conversion, spectroscopy, laser scanner and microscopy. Further expanding the scope, we fully exploit the time-stretch technology to demonstrate a high throughput web inspection system. Web inspection, namely surface inspection is a nondestructive evaluation method which is crucial for semiconductor wafer and thin film production. We successfully report a dark-field web inspection system with line scan speed of 90.9 MHz which is up to 1000 times faster than conventional inspection instruments. The manufacturing of high quality semiconductor wafer and thin film may directly benefit from this technology as it can easily locate defects with area of less than 10 microm x 10 microm where it allows maximum web flow speed of 1.8 km/s. The thesis provides an overview of our web inspection technique, followed by description of the photonic time-stretch technique which is the keystone in our system. A detailed explanation of each component is covered to provide quantitative understanding of the system. Finally, imaging results from a hard-disk sample and flexible films are presented along with performance analysis of the system. This project was the first application of time-stretch to industrial inspection, and was conducted under financial support and with close involvement by Hitachi, Ltd.

New time scale based k-epsilon model for near-wall turbulence

Science.gov (United States)

Yang, Z.; Shih, T. H.

1993-01-01

A k-epsilon model is proposed for wall bonded turbulent flows. In this model, the eddy viscosity is characterized by a turbulent velocity scale and a turbulent time scale. The time scale is bounded from below by the Kolmogorov time scale. The dissipation equation is reformulated using this time scale and no singularity exists at the wall. The damping function used in the eddy viscosity is chosen to be a function of R(sub y) = (k(sup 1/2)y)/v instead of y(+). Hence, the model could be used for flows with separation. The model constants used are the same as in the high Reynolds number standard k-epsilon model. Thus, the proposed model will be also suitable for flows far from the wall. Turbulent channel flows at different Reynolds numbers and turbulent boundary layer flows with and without pressure gradient are calculated. Results show that the model predictions are in good agreement with direct numerical simulation and experimental data.

Optimizing an Intermittent Stretch Paradigm Using ERK1/2 Phosphorylation Results in Increased Collagen Synthesis in Engineered Ligaments

Science.gov (United States)

Paxton, Jennifer Z.; Hagerty, Paul; Andrick, Jonathan J.

2012-01-01

Dynamic mechanical input is believed to play a critical role in the development of functional musculoskeletal tissues. To study this phenomenon, cyclic uniaxial mechanical stretch was applied to engineered ligaments using a custom-built bioreactor and the effects of different stretch frequency, amplitude, and duration were determined. Stretch acutely increased the phosphorylation of p38 (3.5±0.74-fold), S6K1 (3.9±0.19-fold), and ERK1/2 (2.45±0.32-fold). The phosphorylation of ERK1/2 was dependent on time, rather than on frequency or amplitude, within these constructs. ERK1/2 phosphorylation was similar following stretch at frequencies from 0.1 to 1 Hz and amplitudes from 2.5% to 15%, whereas phosphorylation reached maximal levels at 10 min of stretch and returned toward basal within 60 min of stretch. Following a single 10-min bout of cyclic stretch, the cells remained refractory to a second stretch for up to 6 h. Using the phosphorylation of ERK1/2 as a guide, the optimum stretch paradigm was hypothesized to be 10 min of stretch at 2.5% of resting length repeated every 6 h. Consistent with this hypothesis, 7 days of stretch using this optimized intermittent stretch program increased the collagen content of the grafts more than a continuous stretch program (CTL=3.1%±0.44%; CONT=4.8%±0.30%; and INT=5.9%±0.56%). These results suggest that short infrequent bouts of loading are optimal for improving engineered tendon and ligament physiology. PMID:21902469

Foam topology. Bending versus stretching dominated architectures

International Nuclear Information System (INIS)

Deshpande, V.; Ashby, M.; Fleck, N.

2000-01-01

Cellular solids can deform by either the bending or stretching of the cell walls. While most cellular solids are bending-dominated, those that are stretching-dominated are much more weight-efficient for structural applications. In this study we have investigated the topological criteria that dictate the deformation mechanism of a cellular solid by analysing the rigidity (or otherwise) of pin-jointed frameworks comprising inextensional struts. We show that the minimum node connectivity for a special class of lattice structured materials to be stretching-dominated is 6 for 2D foams and 12 for 3D foams. Similarly, sandwich plates comprising of truss cores faced with planar trusses require a minimum node connectivity of 9 to undergo stretching-dominated deformation for all loading states. (author)

Selective Inhibition of Casein Kinase 1 epsilon Minimally Alters Circadian Clock Period

Czech Academy of Sciences Publication Activity Database

Walton, K. M.; Fisher, K.; Rubitski, D.; Marconi, M.; Meng, Q.-J.; Sládek, Martin; Adams, J.; Bass, M.; Chandrasekaran, R.; Butler, T.; Griffor, M.; Rajamohan, F.; Serpa, M.; Chen, Y.; Claffey, M.; Hastings, M.; Loudon, A.; Maywood, E.; Ohren, J.; Doran, A.; Wager, T. T.

2009-01-01

Roč. 330, č. 2 (2009), s. 430-439 ISSN 0022-3565 Institutional research plan: CEZ:AV0Z50110509 Keywords : circadian clock * casein kinase 1 epsilon * inhibitor Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.093, year: 2009

A comparison of two stretching programs for hamstring muscles: A randomized controlled assessor-blinded study.

Science.gov (United States)

Demoulin, Christophe; Wolfs, Sébastien; Chevalier, Madeline; Granado, Caroline; Grosdent, Stéphanie; Depas, Yannick; Roussel, Nathalie; Hage, Renaud; Vanderthommen, Marc

2016-01-01

Most parameters regarding hamstring flexibility training programs have been investigated; however, the joint (i.e. hip or knee) on which the stretching should preferentially be focused needs to be further explored. This randomized controlled assessor-blinded study aimed to investigate the influence of this parameter. We randomly assigned 111 asymptomatic participants with tight hamstring muscles in three groups: a control group and two groups following a different home-based 8-week (five 10-minute sessions per week) hamstring stretching program (i.e. stretching performed by flexing the hip while keeping the knee extended [SH] or by first flexing the hip with a flexed knee and then extending the knee [SK]). Range of motion (ROM) of hip flexion and knee extension were measured before and after the stretching program by means of the straight leg raising test and the passive knee extension angle test, respectively. Eighty-nine participants completed the study. A significant increase in ROM was observed at post-test. Analyses showed significant group-by-time interactions for changes regarding all outcomes. Whereas the increase in hip flexion and knee extension ROM was higher in the stretching groups than in the CG (especially for the SH group p 0.05). In conclusion, the fact that both stretching programs resulted in similar results suggests no influence of the joint at which the stretching is focused upon, as assessed by the straight leg raising and knee extension angle tests.

Randomized Trial of Modified Stretching Exercise Program for Menstrual Low Back Pain.

Science.gov (United States)

Chen, Huei-Mein; Hu, Hsou-Mei

2018-03-01

This study aimed to examine the effectiveness of a modified stretching exercise program on young women with menstrual low back pain. Overall, 127 young women were randomly assigned to the experimental ( n = 63) and control ( n = 64) groups. The experimental group followed the modified stretching exercise program, whereas the control group performed their usual activities. At 1, 4, 8, and 12 months, the experimental group had significantly lower scores on the visual analog scale for pain (95% confidence interval [CI] = [0.73, 1.96]; p < .05) and the Oswestry Low Back Pain Disability Questionnaire than the control group (95% CI = [0.68, 2.03]; p < .001). At 12 months, the experimental group showed significantly higher exercise self-efficacy than the control group (95% CI = [-6.87, 0.62]; p = .003). These findings can be used to enhance self-care capabilities by using the modified stretching exercise program for young women with menstrual low back pain.

METODE ACTIVE ISOLATED STRETCHING (AIS DAN METODE HOLD RELAX STRETCHING (HRS SAMA EFEKTIF DALAM MENINGKATKAN FLEKSIBILITAS OTOT HAMSTRING PADA MAHASISWA AKADEMI FISIOTERAPI WIDYA HUSADA SEMARANG YANG MENGALAMI HAMSTRING MUSCLE TIGHTNESS (HMTs

Directory of Open Access Journals (Sweden)

Akhmad alfajri

2015-08-01

Full Text Available Students with Hamstring Muscle Tightness (HMTs will be at risk of Anterior Crusiatum Ligament (ACL, Low Back Pain (LBP and also Plantar Faciitis. One of the efforts to reduce tightness and improve hamstring muscle flexibility is stretching. Active Isolated Stretching (AIS and Hold Relax Stretching (HRS are the methods of influential stretching to improve muscle flexibility. The goal of the research is to prove that AIS method is equally effective with the HRS method to improve hamstring muscle flexibility to the HMTs patients. The research method was true experimental with pre and post test group design. The research was conducted for 3 weeks and the samples are 23 students in range of 18-25 years old students of physical therapy in Physical Therapy Academy of Widya Husada Semarang which divided into 2 groups; AIS group (n= 12 and HRS group (n= 11. The research used Sit and Reach Test (SRT as the measurement instrument. The result of the research was the average result of AIS group used SRT before treatment was 1.75 cm, SB= 4.309 and after treatment was 10. 58 cm, SB = 8. 005 within p= 0.000 (p 0.05. Those explain that the improvement of hamstring muscle flexibility to the two groups does not show any significant difference. Conclusion from this study was active isolated stretching method and hold relax stretching method are equally effective to improving muscle flexibility of hamstring muscle tightness students of physical therapy in Physical Therapy Academy of Widya Husada Semarang.

Cyclic mechanical stretch down-regulates cathelicidin antimicrobial peptide expression and activates a pro-inflammatory response in human bronchial epithelial cells

Directory of Open Access Journals (Sweden)

Harpa Karadottir

2015-12-01

Full Text Available Mechanical ventilation (MV of patients can cause damage to bronchoalveolar epithelium, leading to a sterile inflammatory response, infection and in severe cases sepsis. Limited knowledge is available on the effects of MV on the innate immune defense system in the human lung. In this study, we demonstrate that cyclic stretch of the human bronchial epithelial cell lines VA10 and BCi NS 1.1 leads to down-regulation of cathelicidin antimicrobial peptide (CAMP gene expression. We show that treatment of VA10 cells with vitamin D3 and/or 4-phenyl butyric acid counteracted cyclic stretch mediated down-regulation of CAMP mRNA and protein expression (LL-37. Further, we observed an increase in pro-inflammatory responses in the VA10 cell line subjected to cyclic stretch. The mRNA expression of the genes encoding pro-inflammatory cytokines IL-8 and IL-1β was increased after cyclic stretching, where as a decrease in gene expression of chemokines IP-10 and RANTES was observed. Cyclic stretch enhanced oxidative stress in the VA10 cells. The mRNA expression of toll-like receptor (TLR 3, TLR5 and TLR8 was reduced, while the gene expression of TLR2 was increased in VA10 cells after cyclic stretch. In conclusion, our in vitro results indicate that cyclic stretch may differentially modulate innate immunity by down-regulation of antimicrobial peptide expression and increase in pro-inflammatory responses.

A new fully human recombinant FSH (follitropin epsilon): two phase I randomized placebo and comparator-controlled pharmacokinetic and pharmacodynamic trials.

Science.gov (United States)

Abd-Elaziz, Khalid; Duijkers, Ingrid; Stöckl, Lars; Dietrich, Bruno; Klipping, Christine; Eckert, Kelvin; Goletz, Steffen

2017-08-01

What are the differences and similarities of pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of the novel recombinant human FSH follitropin epsilon expressed in the human cell line GlycoExpress compared with a Chinese hamster ovary (CHO) derived compound and a urinary derived product? Overall follitropin epsilon, with a fully human glycosylation, shows a comparable PK profile at single-dose as well as multiple-dose administration compared to recombinant CHO-derived FSH as well as urinary derived FSH, whereas the PD properties differ from product to product with follitropin epsilon being most active in PD parameters. Recombinant FSH produced in CHO and FSH obtained from the urine of postmenopausal women show comparable PK and PD properties. However, more recently a comparative study of a recombinant FSH produced in the human cell line PerC6 and a CHO-derived FSH preparation revealed differences in PK and PD properties of the molecule. Both studies were randomized, placebo- and comparator-controlled, single-blind phase I studies in healthy pituitary-suppressed female volunteers aged 18 and 40 years. The single-dose, dose escalation study included 19 women (April 2011 to September 2011) with three ascending dose levels per subject or placebo/comparators with a 14-day washout phase between dosings. The multiple-dose study included 57 women (October 2011 to April 2012) in five cohorts with three dose levels versus placebo and two comparators. Randomization to the respective treatment was performed after successful downregulation of the pituitary gland prior to Investigational Medicinal Product dosing. In the single-dose study, 12 subjects received follitropin epsilon (25, 75, 150 and 300 IU) in three of four possible ascending doses and seven subjects received one dose of two comparators (150 IU Bravelle and 150 IU Gonal-f) and placebo in random order in each treatment period. In the multiple-dose study, 30 subjects received follitropin epsilon (75 IU or

Optofluidic time-stretch microscopy: recent advances

Science.gov (United States)

Lei, Cheng; Nitta, Nao; Ozeki, Yasuyuki; Goda, Keisuke

2018-04-01

Flow cytometry is an indispensable method for valuable applications in numerous fields such as immunology, pathology, pharmacology, molecular biology, and marine biology. Optofluidic time-stretch microscopy is superior to conventional flow cytometry methods for its capability to acquire high-quality images of single cells at a high-throughput exceeding 10,000 cells per second. This makes it possible to extract copious information from cellular images for accurate cell detection and analysis with the assistance of machine learning. Optofluidic time-stretch microscopy has proven its effectivity in various applications, including microalga-based biofuel production, evaluation of thrombotic disorders, as well as drug screening and discovery. In this review, we discuss the principles and recent advances of optofluidic time-stretch microscopy.

D'une ouverture de la voyelle /epsilon/ en finale absolue en francais quebecois : analyse acoustique et perceptive

Science.gov (United States)

Riverin-Coutlee, Josiane

Cette contribution est consacree a l'ouverture du /epsilon/ en finale absolue, un phenomene phonetique repute etre en declin en francais quebecois et caracteristique de locuteurs âges, peu scolarises, issus de milieux populaires et s'exprimant en situation de communication informelle. Une analyse acoustique de 480 voyelles /epsilon/ issues de la parole formelle de 40 jeunes etudiants universitaires originaires des centres urbains de Saguenay et de Quebec revele toutefois que le phenomene est encore bien vivant en francais quebecois et qu'il est plus frequent chez les locuteurs de Saguenay, une tendance validee auditivement par accord inter-juges. Les resultats d'un test de discrimination et d'identification mene aupres de 26 etudiants universitaires originaires de ces deux memes villes indiquent que les auditeurs naifs de Saguenay semblent moins sensibles a la variation et moins enclins a juger de l'origine geographique d'un locuteur a partir de sa prononciation de la voyelle /epsilon/ en fin de mot.

Stretch due to Penile Prosthesis Reservoir Migration

Directory of Open Access Journals (Sweden)

E. Baten

2016-03-01

Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

Recombinant Alpha, Beta, and Epsilon Toxins of Clostridium perfringens: Production Strategies and Applications as Veterinary Vaccines

Directory of Open Access Journals (Sweden)

Marcos Roberto A. Ferreira

2016-11-01

Full Text Available Clostridium perfringens is a spore-forming, commensal, ubiquitous bacterium that is present in the gastrointestinal tract of healthy humans and animals. This bacterium produces up to 18 toxins. The species is classified into five toxinotypes (A–E according to the toxins that the bacterium produces: alpha, beta, epsilon, or iota. Each of these toxinotypes is associated with myriad different, frequently fatal, illnesses that affect a range of farm animals and humans. Alpha, beta, and epsilon toxins are the main causes of disease. Vaccinations that generate neutralizing antibodies are the most common prophylactic measures that are currently in use. These vaccines consist of toxoids that are obtained from C. perfringens cultures. Recombinant vaccines offer several advantages over conventional toxoids, especially in terms of the production process. As such, they are steadily gaining ground as a promising vaccination solution. This review discusses the main strategies that are currently used to produce recombinant vaccines containing alpha, beta, and epsilon toxins of C. perfringens, as well as the potential application of these molecules as vaccines for mammalian livestock animals.

Transport, mixing and stretching in a chaotic Stokes flow: The two-roll mill

International Nuclear Information System (INIS)

Kaper, T.J.; Wiggins, S.

1989-01-01

We present the outline and preliminary results of an analytical and numerical study of transport, mixing, and stretching in a chaotic Stokes' flow in a two-roll mill apparatus. We use the theory of dynamical systems to describe the rich behavior and structure exhibited by these flows. The main features are the homoclinic tangle which functions as the backbone of the chaotic mixing region, the Smale horseshoe, and the island chains. We then use our detailed knowledge of these structures to develop a theory of transport and stretching of fluid in the chaotic regime. In particular, we show how a specific set of tools for adiabatic chaos- the adiabatic Melnikov function lobe area and flux computations and the adiabatic switching method is ideally suited to develop this theory of transport, mixing and stretching in time-dependent two-dimensional Stokes' flows. 19 refs., 8 figs

Interleukin-1 beta induced synthesis of protein kinase C-delta and protein kinase C-epsilon in EL4 thymoma cells: possible involvement of phosphatidylinositol 3-kinase.

Science.gov (United States)

Varley, C L; Royds, J A; Brown, B L; Dobson, P R

2001-01-01

We present evidence here that the proinflammatory cytokine, interleukin-1 beta (IL-1 beta) stimulates a significant increase in protein kinase C (PKC)-epsilon and PKC-delta protein levels and increases PKC-epsilon, but not PKC-delta, transcripts in EL4 thymoma cells. Incubation of EL4 cells with IL-1 beta induced protein synthesis of PKC-epsilon (6-fold increase) by 7 h and had a biphasic effect on PKC-delta levels with peaks at 4 h (2-fold increase) and 24 h (4-fold increase). At the level of mRNA, PKC-epsilon, but not PKC-delta levels, were induced after incubation of EL4 cells with IL-1 beta. The signalling mechanisms utilized by IL-1 beta to induce the synthesis of these PKC isoforms were investigated. Two phosphatidylinositol (PI) 3-kinase-specific inhibitors, wortmannin and LY294002, inhibited IL-1 beta-induced synthesis of PKC-epsilon. However, the PI 3-kinase inhibitors had little effect on the IL-1 beta-induced synthesis of PKC-delta in these cells. Our results indicate that IL-1 beta induced both PKC-delta and PKC-epsilon expression over different time periods. Furthermore, our evidence suggests that IL-1 beta induction of PKC-epsilon, but not PKC-delta, may occur via the PI 3-kinase pathway. Copyright 2001 S. Karger AG, Basel

The Effect of Anabolic Steroid Administration on Passive Stretching-Induced Expression of Mechano-Growth Factor in Skeletal Muscle

Directory of Open Access Journals (Sweden)

Satoshi Ikeda

2013-01-01

Full Text Available Background. Stretching of skeletal muscle induces expression of the genes which encode myogenic transcription factors or muscle contractile proteins and results in muscle growth. Anabolic steroids are reported to strengthen muscles. We have previously studied the effects of muscle stretching on gene expression. Here, we studied the effect of a combination of passive stretching and the administration of an anabolic steroid on mRNA expression of a muscle growth factor, insulin-like growth factor-I autocrine variant, or mechano-growth factor (MGF. Methods. Twelve 8-week-old male Wistar rats were used. Metenolone was administered and passive repetitive dorsiflexion and plantar flexion of the ankle joint performed under deep anesthesia. After 24 h, the gastrocnemius muscles were removed and the mRNA expression of insulin-like growth factor-I autocrine variant was measured using quantitative real-time polymerase chain reaction. Results. Repetitive stretching in combination with metenolone, but not stretching alone, significantly increased MGF mRNA expression. Conclusion. Anabolic steroids enhance the effect of passive stretching on MGF expression in skeletal muscle.

Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

Science.gov (United States)

Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

2012-08-01

Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

Immediate effects of different types of stretching exercises on badminton jump smash.

Science.gov (United States)

Jang, Hwi S; Kim, Daeho; Park, Jihong

2018-01-01

Since different types of stretching exercises may alter athletic performance, we compared the effects of three types of stretching exercises on badminton jump smash. Sixteen male collegiate badminton players performed one of three different stretching exercises in a counterbalanced order on different days. Static stretching had seven typical stretches, while dynamic stretching involved nine dynamic movements, and resistance dynamic stretching was performed with weighted vests and dumbbells. Before and after each stretching exercise, subjects performed 20 trials of jump smashes. Dependent measurements were the jump heights during jump smashes, velocities of jump-smashed shuttlecocks, and drop point of jump-smashed shuttlecocks. To test the effects of each stretching exercise, we performed mixed model ANOVAs and calculated between-time effect sizes (ES). Each stretching exercise improved the jump heights during jump smashes (type main effect: F(2,75)=1.19, P=0.31; static stretching: 22.1%, Pjump-smashed shuttlecocks (type main effect: F(2,75)=2.18, P=0.12; static stretching: 5.7%, P=0.61, ES=0.39; dynamic stretching: 3.4%, P=0.94, ES=0.28; resistance dynamic stretching: 6%, P=0.50, ES=0.66). However, there were no differences among the stretching exercises for any measurement. The drop point of jump-smashed shuttlecocks did not change (interaction: F(2,75)=0.88, P=0.42). All stretching exercises improved badminton jump smash performance, but we could not determine the best protocol. Since badminton requires high-speed movement and explosive force, we suggest performing dynamic stretching or resistance dynamic stretching.

Lattice stretching bistability and dynamic heterogeneity

DEFF Research Database (Denmark)

Christiansen, Peter Leth; Savin, A. V.; Zolotaryuk, A. V.

2012-01-01

A simple one-dimensional lattice model is suggested to describe the experimentally observed plateau in force-stretching diagrams for some macromolecules. This chain model involves the nearest-neighbor interaction of a Morse-like potential (required to have a saturation branch) and a harmonic second......-neighbor coupling. Under an external stretching applied to the chain ends, the intersite Morse-like potential results in the appearance of a double-well potential within each chain monomer, whereas the interaction between the second neighbors provides a homogeneous bistable (degenerate) ground state, at least...... stretched bonds with a double-well potential. This case allows us to explain the existence of a plateau in the force-extension diagram for DNA and α-helix protein. Finally, the soliton dynamics are studied in detail....

Development of inhomogeneous {kappa}-{epsilon}-{upsilon}{sup 2} turbulence model for 3D flow analysis of SMART-P

Energy Technology Data Exchange (ETDEWEB)

Chun, K. H.; Whang, Y. D.; Yoon, H. Y.; Kim, H. C

2003-07-01

The objective of the present report is to select and develop a turbulence model that will be implemented in TASS-3D code for 3-D heat and fluid analysis on the integral reactor, SMART-P primary coolant system. The turbulence model was selected with the consideration on the economy, accuracy, theorization and applicability for the complex three dimensional flow, natural convection and the high Reynolds number turbulent flow of SMART-P.On the models investigated in this present study, the standard {kappa}-{epsilon} model of high Reynolds model, the {kappa}-{epsilon}-{upsilon}{sup 2} model and ERRSM of low Reynolds model were selected out of them finally. The {kappa}-{epsilon}-{upsilon}{sup 2} model was selected as the applicable turbulence model for three dimensional flow analysis of SMART-P. The problem of original {kappa}-{epsilon}-{upsilon}{sup 2} model is the amplification of the pressure strain rate in the log region. The amplification is caused by Elliptic Relaxation Equation(ERE). The present model approaches inhomogeneous for the source term of the ERE to reduce the pressure-strain amplification. The source term was decomposed into homogeneous part and inhomogeneous part and derived as a form of variable coefficients of the ERE. The pressure strain and dissipation terms were fully coupled with the source term of the ERE. The pressure diffusion was modified to treat the boundary conditions indirectly and the pressure strain of the inhomogeneous correction ERE was noticeably decreased in both log layer and outer layer. The results of the inhomogeneous correction {kappa}-{epsilon}-{upsilon}{sup 2} model showed a good agreement with DNS results for channel flows and estimated improved results on the turbulent components in comparison with other models.

Broadband Epsilon-near-Zero Reflectors Enhance the Quantum Efficiency of Thin Solar Cells at Visible and Infrared Wavelengths

KAUST Repository

Labelle, A. J.; Bonifazi, Marcella; Tian, Y.; Wong, C.; Hoogland, S.; Favraud, Gael; Walters, G.; Sutherland, B.; Liu, M.; Li, Jun; Zhang, Xixiang; Kelley, Shana O.; Sargent, E. H.; Fratalocchi, Andrea

2017-01-01

The engineering of broadband absorbers to harvest white light in thin-film semiconductors is a major challenge in developing renewable materials for energy harvesting. Many solution-processed materials with high manufacturability and low cost, such as semiconductor quantum dots, require the use of film structures with thicknesses on the order of 1 μm to absorb incoming photons completely. The electron transport lengths in these media, however, are 1 order of magnitude smaller than this length, hampering further progress with this platform. Herein, we show that, by engineering suitably disordered nanoplasmonic structures, we have created a new class of dispersionless epsilon-near-zero composite materials that efficiently harness white light. Our nanostructures localize light in the dielectric region outside the epsilon-near-zero material with characteristic lengths of 10-100 nm, resulting in an efficient system for harvesting broadband light when a thin absorptive film is deposited on top of the structure. By using a combination of theory and experiments, we demonstrate that ultrathin layers down to 50 nm of colloidal quantum dots deposited atop the epsilon-near-zero material show an increase in broadband absorption ranging from 200% to 500% compared to a planar structure of the same colloidal quantum-dot-absorber average thickness. When the epsilon-near-zero nanostructures were used in an energy-harvesting module, we observed a spectrally averaged 170% broadband increase in the external quantum efficiency of the device, measured at wavelengths between 400 and 1200 nm. Atomic force microscopy and photoluminescence excitation measurements demonstrate that the properties of these epsilon-near-zero structures apply to general metals and could be used to enhance the near-field absorption of semiconductor structures more widely. We have developed an inexpensive electrochemical deposition process that enables scaled-up production of this nanomaterial for large

Broadband Epsilon-near-Zero Reflectors Enhance the Quantum Efficiency of Thin Solar Cells at Visible and Infrared Wavelengths

KAUST Repository

Labelle, A. J.

2017-02-03

The engineering of broadband absorbers to harvest white light in thin-film semiconductors is a major challenge in developing renewable materials for energy harvesting. Many solution-processed materials with high manufacturability and low cost, such as semiconductor quantum dots, require the use of film structures with thicknesses on the order of 1 μm to absorb incoming photons completely. The electron transport lengths in these media, however, are 1 order of magnitude smaller than this length, hampering further progress with this platform. Herein, we show that, by engineering suitably disordered nanoplasmonic structures, we have created a new class of dispersionless epsilon-near-zero composite materials that efficiently harness white light. Our nanostructures localize light in the dielectric region outside the epsilon-near-zero material with characteristic lengths of 10-100 nm, resulting in an efficient system for harvesting broadband light when a thin absorptive film is deposited on top of the structure. By using a combination of theory and experiments, we demonstrate that ultrathin layers down to 50 nm of colloidal quantum dots deposited atop the epsilon-near-zero material show an increase in broadband absorption ranging from 200% to 500% compared to a planar structure of the same colloidal quantum-dot-absorber average thickness. When the epsilon-near-zero nanostructures were used in an energy-harvesting module, we observed a spectrally averaged 170% broadband increase in the external quantum efficiency of the device, measured at wavelengths between 400 and 1200 nm. Atomic force microscopy and photoluminescence excitation measurements demonstrate that the properties of these epsilon-near-zero structures apply to general metals and could be used to enhance the near-field absorption of semiconductor structures more widely. We have developed an inexpensive electrochemical deposition process that enables scaled-up production of this nanomaterial for large

Resveratrol-loaded poly({epsilon}-caprolactone) microparticles: preparation and characterization; Microparticulas de poli({epsilon}-caprolactona) contendo resveratrol: preparacao e caracterizacao

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

Resveratrol-loaded poly({epsilon}-caprolactone) (PCL) microparticles were obtained by simple emulsion/solvent evaporation method. Three drug-loaded formulations were prepared with the aim of investigating the influence of composition on the encapsulation efficiency. Morphological and spectroscopic methods were performed for these materials. The microparticles revealed residual moisture close to 1.5% and encapsulation efficiency above 80%. Spherical shape and smooth surface were observed by SEM. No pores were either verified. Resveratrol-loaded microparticles showed an average particle size of around 50 {mu}m. X-ray diffraction analysis demonstrated that the microencapsulation reduced the drug crystallinity. The FTIR results suggest that no chemical bond was formed between polymer and drug. (author)

Viscoelastic optical nonlocality of doped cadmium oxide epsilon-near-zero thin films

Energy Technology Data Exchange (ETDEWEB)

Luk, Ting S.; De Ceglia, Domenico; Scalora, Michael; Vincenti, Maria A.; Campione, Salvatore; Kelley, Kyle; Maria, Jon-Paul; Keeler, Gordon A.

2017-08-01

Optical nonlocalities are elusive and hardly observable in traditional plasmonic materials like noble and alkali metals. Here we experimentally observe and theoretically model viscoelastic nonlocalities in the infrared optical response of a doped, cadmium oxide epsilon-near-zero thin film. The nonlocality is clearly detectable thanks to the low damping rate of conduction electrons and the virtual absence of interband transitions at infrared wavelengths. We describe the motion of conduction electrons using a hydrodynamic model for a viscoelastic fluid, and find excellent agreement with experimental results. The electrons’ elasticity blue-shifts the infrared plasmonic resonance associated with the main epsilon-near-zero mode, and triggers the onset of higher-order resonances due to the excitation of electron-pressure modes above the bulk plasma frequency. We also provide evidence of the existence of nonlocal damping, i.e., viscosity, in the motion of optically-excited conduction electrons using a combination of spectroscopic ellipsometry data and predictions based on the viscoelastic hydrodynamic model.

Effects of climate and lifeform on dry matter yield (epsilon) from simulations using BIOME BGC. [ecosystem process model for vegetation biomass production using daily absorbed photosynthetically active radiation

Science.gov (United States)

Hunt, E. R., Jr.; Running, Steven W.

1992-01-01

An ecosystem process simulation model, BIOME-BGC, is used in a sensitivity analysis to determine the factors that may cause the dry matter yield (epsilon) and annual net primary production to vary for different ecosystems. At continental scales, epsilon is strongly correlated with annual precipitation. At a single location, year-to-year variation in net primary production (NPP) and epsilon is correlated with either annual precipitation or minimum air temperatures. Simulations indicate that forests have lower epsilon than grasslands. The most sensitive parameter affecting forest epsilon is the total amount of living woody biomass, which affects NPP by increasing carbon loss by maintenance respiration. A global map of woody biomass should significantly improve estimates of global NPP using remote sensing.

[Stretching the triceps surae muscle after 40 degrees C warming in patients with cerebral palsy].

Science.gov (United States)

Lespargot, A; Robert, M; Khouri, N

2000-11-01

Equinus in patients with cerebral palsy results from at least two factors: excessive contracture of the triceps surae and muscle retraction. Tendon surgery and progressive lengthening techniques using plaster walking boots can provide variable improvement in retraction. We compared the effect of this technique when applied with or without prior 40 degrees C warming in the same patients. We also assessed the efficacy of this treatment method in terms or degree of retraction, patient age, puberty maturity, and sex. This series included 70 muscles in 52 patients with cerebral palsy aged 2 years 11 months to 21 years (mean 8 years 3 months). Common features in these patients were: - equinus mainly explained by triceps retraction, - no history of prior surgery on the triceps tendon, - knee flexion less than 15 degrees in the upright position, - easily reduced lateral deformation of the foot, - absence of mediotarsal dislocation, - triceps stretching could be achieved without triggering unacceptably intense contracture. The retraction of the triceps surae was measured from the maximal passive dorsal flexion angle of the foot, before and after applying each stretching boot. The difference between these measurements gave the gain obtained with the plaster boot. Protocol R- (stretching with plaster boot) consisted in a series of slow stretchings for 10 minutes before making the boot which was worn 7 days. Recurrent retraction in these same patients warranted another treatment within a delay of 3 to 17 months (mean delay 8.7 months). The same treatment then followed protocol R+ where the stretching was preceded by immersion of the segment in a 40 degrees C water bath for 10 minutes. Mean gain obtained with protocol R+ (warming) was 6.8 degrees knee extended and 7.1 degrees knee flexed. These differences were highly significant in both cases (p knee extended and for 32 muscles, knee flexed. The gain was not related to age, sex or puberty maturity. It was not related to the

Comparative analysis of biological activities of Der p I-derived peptides on Fc epsilon receptor-bearing cells from Dermatophagoides pteronyssinus-sensitive patients.

Science.gov (United States)

Jeannin, P; Pestel, J; Bossus, M; Lassalle, P; Tartar, A; Tonnel, A B

1993-01-01

The ability of four uncoupled synthetic peptides (p52-71, p117-133, p176-187, p188-199) derived from Der p I, a major allergen from the house dust mite Dermatophagoides pteronyssinus (Dpt) to stimulate Fc epsilon R+ cells from Dpt-sensitive patients was comparatively analysed. Each free peptide may specifically stimulate basophils (Fc epsilon RI+ cells) and platelets (Fc epsilon RII+ cells) from patients with significant levels of anti-Der p I IgE antibodies; p52-71 and p117-133 appear the best cell stimulation inducers. Both concentration-dependent biological activities of Der p I-peptide on Fc epsilon R+ cells are enhanced by coupling peptide to a carrier (as human serum albumin). Interestingly each Der p I-sensitive patient tested presents an individual pattern of response to peptide. Thus, from our results it appears that different Der p I sequences could be involved in the immune response to Der p I. PMID:7682161

Comparative analysis of biological activities of Der p I-derived peptides on Fc epsilon receptor-bearing cells from Dermatophagoides pteronyssinus-sensitive patients.

Science.gov (United States)

Jeannin, P; Pestel, J; Bossus, M; Lassalle, P; Tartar, A; Tonnel, A B

1993-04-01

The ability of four uncoupled synthetic peptides (p52-71, p117-133, p176-187, p188-199) derived from Der p I, a major allergen from the house dust mite Dermatophagoides pteronyssinus (Dpt) to stimulate Fc epsilon R+ cells from Dpt-sensitive patients was comparatively analysed. Each free peptide may specifically stimulate basophils (Fc epsilon RI+ cells) and platelets (Fc epsilon RII+ cells) from patients with significant levels of anti-Der p I IgE antibodies; p52-71 and p117-133 appear the best cell stimulation inducers. Both concentration-dependent biological activities of Der p I-peptide on Fc epsilon R+ cells are enhanced by coupling peptide to a carrier (as human serum albumin). Interestingly each Der p I-sensitive patient tested presents an individual pattern of response to peptide. Thus, from our results it appears that different Der p I sequences could be involved in the immune response to Der p I.

Acute effects of static and dynamic stretching on jump performance after 15 min of reconditioning shooting phase in basketball players.

Science.gov (United States)

Annino, Giuseppe; Ruscello, Bruno; Lebone, Pietro; Palazzo, Francesco; Lombardo, Mauro; Padua, Elvira; Verdecchia, Luca; Tancredi, Virginia; Iellamo, Ferdinando

2017-04-01

The aim of this study was to assess the effects of static (SS) and dynamic stretching (DS) on vertical jump performance executed before, immediately after and at the end of the shooting phase (i.e., 15 min later), as to simulate the actual conditions preceding a match, in professional basketball players. Ten elite basketball players (age: 29±6.73 years, height: 194.67±7.75 cm, weight: 91±8.17 kg and BMI 23.8±7.91 kg.m-2) participated to the study. SS and DS protocols were administered during the first training session of the week, 48 hours after the championship match. Stretching protocols consisted in ~7 minutes of general warm-up phase followed by ~8 minutes of SS and DS, performed with a cross-over design., and ~15 minutes of a specific warm-up shooting phase (SP). Vertical jump tests consisted in counter movement jump (CMJ) and CMJ with arm swings (CMJas) and were performed immediately after the end of each stretching phase (preS, postS, postSP). A significant decrease (P=0.05; η2partial=0.29) in jumping tests height occurred in CMJas, when performed after the SS (i.e., PostS). However, no significant differences in jumping performances, occurred after the general warm phase and the specific warm-up shooting phase, between the two stretching protocols. These results would indicate that, overall, stretching routines either dynamic or static, performed before a basketball match are transient and affect only marginally leg muscles performance. Stretching routines, particularly the dynamic ones, may be useful to maintain muscle performance before a competition, provided that this latter begins shortly after.

Epsilon Aurigae - Two-year Totality Transpiring

Science.gov (United States)

Kloppenborg, Brian K.; Stencel, R. E.; Hopkins, J. L.

2010-01-01

The 27 year period eclipsing binary, epsilon Aurigae, exhibits the hallmarks of a classical Algol system, except that the companion to the F supergiant primary star is surprisingly under-luminous for its mass. Eclipse ingress appears to have begun shortly after the predicted time in August 2009, near JD 2,455,065. At the University of Denver, we have focused on near-infrared interferometry, spectroscopy, and photometry with the superior instrumentation available today, compared to that of the 1983 eclipse. Previously obtained interferometry indicates that the source is asymmetric (Stencel, et. al. 2009 APLJ) and initial CHARA+MIRC closure-phase imaging shows hints of resolved structures. In parallel, we have pursued SPEX near-IR spectra at NASA IRTF in order to confirm whether CO molecules only seen during the second half of the 1983 eclipse will reappear on schedule. Additionally, we have obtained J and H band photometry using an Optec SSP-4 photometer with a newly written control and analysis suite. Our goal is to refine daytime photometric methods in order to provide coverage of the anticipated mid-eclipse brightening during summer 2010, from our high-altitude observatory atop Mt. Evans, Colorado. Also, many parallel observations are ongoing as part of the epsilon Aurigae international campaign (http://www.hposoft.com/Campaign09.html). In this report, we describe the progress of the eclipse and ongoing observations. We invite interested parties to get involved with the campaign for coverage of the 2009-2011 eclipse via the campaign websites: http://www.hposoft.com/Campaign09.html - and - http://www.du.edu/ rstencel/epsaur.htm - and - http://www.citizensky.org . This research is supported in part by the bequest of William Herschel Womble to the University of Denver. We are grateful to the participants in the observing campaign and invite interested parties to join us in monitoring the star for the balance of the eclipse.

Metabolic engineering of potato tuber carotenoids through tuber-specific silencing of lycopene epsilon cyclase

Directory of Open Access Journals (Sweden)

Papacchioli Velia

2006-06-01

Full Text Available Abstract Background Potato is a major staple food, and modification of its provitamin content is a possible means for alleviating nutritional deficiencies. beta-carotene is the main dietary precursor of vitamin A. Potato tubers contain low levels of carotenoids, composed mainly of the xanthophylls lutein, antheraxanthin, violaxanthin, and of xanthophyll esters. None of these carotenoids have provitamin A activity. Results We silenced the first dedicated step in the beta-epsilon- branch of carotenoid biosynthesis, lycopene epsilon cyclase (LCY-e, by introducing, via Agrobacterium-mediated transformation, an antisense fragment of this gene under the control of the patatin promoter. Real Time measurements confirmed the tuber-specific silencing of Lcy-e. Antisense tubers showed significant increases in beta-beta-carotenoid levels, with beta-carotene showing the maximum increase (up to 14-fold. Total carotenoids increased up to 2.5-fold. These changes were not accompanied by a decrease in lutein, suggesting that LCY-e is not rate-limiting for lutein accumulation. Tuber-specific changes in expression of several genes in the pathway were observed. Conclusion The data suggest that epsilon-cyclization of lycopene is a key regulatory step in potato tuber carotenogenesis. Upon tuber-specific silencing of the corresponding gene, beta-beta-carotenoid and total carotenoid levels are increased, and expression of several other genes in the pathway is modified.

Bruxism: Is There an Indication for Muscle-Stretching Exercises?

Science.gov (United States)

Gouw, Simone; de Wijer, Anton; Creugers, Nico Hj; Kalaykova, Stanimira I

Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.

Epsilon wave on an electronic loop in a case of arrhythmogenic right ventricular dysplasia with myocarditis: an updated definition of the Epsilon wave.

Science.gov (United States)

Fontaine, Guy Hugues; Duthoit, Guillaume; Li, Guoliang; Andreoletti, L; Gandjbakhch, Estelle; Frank, Robert

2017-07-01

A young man presented with a history of myocarditis with palpitations and dizziness. He had implantation of a loop recorder that showed repetitive short episodes of VT. In addition, there were fragmented potentials immediately following the large and sharp electrograms (EGMs) before as well as after episodes of VT suggesting an Epsilon wave. This signal can be observed in multiple cardiac conditions including coronary artery disease. It was originally recorded on the epicardium as well as on the endocardium. However, in ARVD it can be defined as an electric signal observed after the end of the QRS complex in the right as opposed to the left precordial leads (difference ≥ 25 ms). It can also be an aid to the diagnosis of patients with ARVD who have other signs or symptoms suggesting ARVD including episodes of myocarditis. This potential consists of a slurring at the end of the QRS complex or an independent potential after the return to the isoelectric line. It can be better observed by increasing amplification of the ECG tracing as well as double speed using the Fontaine lead system. Epsilon wave too small to be recorded on the standard ECG can be extracted by Signal Averaging ECG SAECG). Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For Permissions, please email: journals.permissions@oup.com.

Role of androgen receptor on cyclic mechanical stretch-regulated proliferation of C2C12 myoblasts and its upstream signals: IGF-1-mediated PI3K/Akt and MAPKs pathways.

Science.gov (United States)

Ma, Yiming; Fu, Shaoting; Lu, Lin; Wang, Xiaohui

2017-07-15

To detect the effects of androgen receptor (AR) on cyclic mechanical stretch-modulated proliferation of C2C12 myoblasts and its pathways: roles of IGF-1, PI3K and MAPK. C2C12 were randomly divided into five groups: un-stretched control, six or 8 h of fifteen percent stretch, and six or 8 h of twenty percent stretch. Cyclic mechanical stretch of C2C12 were completed using a computer-controlled FlexCell Strain Unit. Cell proliferation and IGF-1 concentration in medium were detected by CCK8 and ELISA, respectively. Expressions of AR and IGF-1R, and expressions and activities of PI3K, p38 and ERK1/2 in stretched C2C12 cells were determined by Western blot. ①The proliferation of C2C12 cells, IGF-1 concentration in medium, expressions of AR and IGF-1R, and activities of PI3K, p38 and ERK1/2 were increased by 6 h of fifteen percent stretch, while decreased by twenty percent stretch for six or 8 h ②The fifteen percent stretch-increased proliferation of C2C12 cells was reversed by AR inhibitor, Flutamide. ③The increases of AR expression, activities of PI3K, p38 and ERK1/2 resulted from fifteen percent stretch were attenuated by IGF-1 neutralizing antibody, while twenty percent stretch-induced decreases of the above indicators were enhanced by recombinant IGF-1. ④Specific inhibitors of p38, ERK1/2 and PI3K all decreased the expression of AR in fifteen percent and twenty percent of stretched C2C12 cells. Cyclic mechanical stretch modulated the proliferation of C2C12 cells, which may be attributed to the alterations of AR via IGF-1-PI3K/Akt and IGF-1-MAPK (p38, ERK1/2) pathways in C2C12 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Nesprin-2 epsilon: A novel nesprin isoform expressed in human ovary and Ntera-2 cells

International Nuclear Information System (INIS)

Lam, Le Thanh; Boehm, Sabrina V.; Roberts, Roland G.; Morris, Glenn E.

2011-01-01

Highlights: → A novel epsilon isoform of nesprin-2 has been discovered. → This 120 kDa protein was predicted by bioinformatic analysis, but has not previously been observed. → It is the main isoform expressed in a teratocarcinoma cell line and is also found in ovary. → Like other nesprins, it is located at the nuclear envelope. → We suggest it may have a role in very early development or in some ovary-specific function. -- Abstract: The nuclear envelope-associated cytoskeletal protein, nesprin-2, is encoded by a large gene containing several internal promoters that produce shorter isoforms. In a study of Ntera-2 teratocarcinoma cells, a novel isoform, nesprin-2-epsilon, was found to be the major mRNA and protein product of the nesprin-2 gene. Its existence was predicted by bioinformatic analysis, but this is the first direct demonstration of both the mRNA and the 120 kDa protein which is located at the nuclear envelope. In a panel of 21 adult and foetal human tissues, the nesprin-2-epsilon mRNA was strongly expressed in ovary but was a minor isoform elsewhere. The expression pattern suggests a possible link with very early development and a likely physiological role in ovary.

Passive Repetitive Stretching for a Short Duration within a Week Increases Myogenic Regulatory Factors and Myosin Heavy Chain mRNA in Rats' Skeletal Muscles

Directory of Open Access Journals (Sweden)

Yurie Kamikawa

2013-01-01

Full Text Available Stretching is a stimulation of muscle growth. Stretching for hours or days has an effect on muscle hypertrophy. However, differences of continuous stretching and repetitive stretching to affect muscle growth are not well known. To clarify the difference of continuous and repetitive stretching within a short duration, we investigated the gene expression of muscle-related genes on stretched skeletal muscles. We used 8-week-old male Wistar rats ( for this study. Animals medial gastrocnemius muscle was stretched continuously or repetitively for 15 min daily and 4 times/week under anesthesia. After stretching, muscles were removed and total RNA was extracted. Then, reverse transcriptional quantitative real-time PCR was done to evaluate the mRNA expression of MyoD, myogenin, and embryonic myosin heavy chain (MyHC. Muscles, either stretched continuously or repetitively, increased mRNA expression of MyoD, myogenin, and embryonic MyHC more than unstretched muscles. Notably, repetitive stretching resulted in more substantial effects on embryonic MyHC gene expression than continuous stretching. In conclusion, passive stretching for a short duration within a week is effective in increasing myogenic factor expression, and repetitive stretching had more effects than continuous stretching for skeletal muscle on muscle growth. These findings are applicable in clinical muscle-strengthening therapy.

Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

International Nuclear Information System (INIS)

Ostrow, Lyle W.; Suchyna, Thomas M.; Sachs, Frederick

2011-01-01

Highlights: → Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. → Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca 2+ permeant SACs. → The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. → Stretch-induced ET-1 production depends on a calcium influx. → SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch ( 2+ threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

Mutant RBL mast cells defective in Fc epsilon RI signaling and lipid raft biosynthesis are reconstituted by activated Rho-family GTPases.

Science.gov (United States)

Field, K A; Apgar, J R; Hong-Geller, E; Siraganian, R P; Baird, B; Holowka, D

2000-10-01

Characterization of defects in a variant subline of RBL mast cells has revealed a biochemical event proximal to IgE receptor (Fc epsilon RI)-stimulated tyrosine phosphorylation that is required for multiple functional responses. This cell line, designated B6A4C1, is deficient in both Fc epsilon RI-mediated degranulation and biosynthesis of several lipid raft components. Agents that bypass receptor-mediated Ca(2+) influx stimulate strong degranulation responses in these variant cells. Cross-linking of IgE-Fc epsilon RI on these cells stimulates robust tyrosine phosphorylation but fails to mobilize a sustained Ca(2+) response. Fc epsilon RI-mediated inositol phosphate production is not detectable in these cells, and failure of adenosine receptors to mobilize Ca(2+) suggests a general deficiency in stimulated phospholipase C activity. Antigen stimulation of phospholipases A(2) and D is also defective. Infection of B6A4C1 cells with vaccinia virus constructs expressing constitutively active Rho family members Cdc42 and Rac restores antigen-stimulated degranulation, and active Cdc42 (but not active Rac) restores ganglioside and GPI expression. The results support the hypothesis that activation of Cdc42 and/or Rac is critical for Fc epsilon RI-mediated signaling that leads to Ca(2+) mobilization and degranulation. Furthermore, they suggest that Cdc42 plays an important role in the biosynthesis and expression of certain components of lipid rafts.

Meniscal tissue regeneration in porous 50/50 copoly(L-lactide/epsilon-caprolactone) implants

NARCIS (Netherlands)

de Groot, J. H.; Zijlstra, F. M.; Kuipers, HW; Pennings, A. J.; Veth, RPH; Jansen, HWB

Porous materials of a high-molecular-weight 50/50 copolymer of L-lactide and epsilon-caprolactone with different compression moduli were used for meniscal repair. In contrast to the previously used 4,4'-diphenylmethane and 1,6-trans-cyclohexane diisocyanates containing polyurethanes, degradation

Aitken extrapolation and epsilon algorithm for an accelerated solution of weakly singular nonlinear Volterra integral equations

International Nuclear Information System (INIS)

Mesgarani, H; Parmour, P; Aghazadeh, N

2010-01-01

In this paper, we apply Aitken extrapolation and epsilon algorithm as acceleration technique for the solution of a weakly singular nonlinear Volterra integral equation of the second kind. In this paper, based on Tao and Yong (2006 J. Math. Anal. Appl. 324 225-37.) the integral equation is solved by Navot's quadrature formula. Also, Tao and Yong (2006) for the first time applied Richardson extrapolation to accelerating convergence for the weakly singular nonlinear Volterra integral equations of the second kind. To our knowledge, this paper may be the first attempt to apply Aitken extrapolation and epsilon algorithm for the weakly singular nonlinear Volterra integral equations of the second kind.

Solving binary-state multi-objective reliability redundancy allocation series-parallel problem using efficient epsilon-constraint, multi-start partial bound enumeration algorithm, and DEA

International Nuclear Information System (INIS)

Khalili-Damghani, Kaveh; Amiri, Maghsoud

2012-01-01

In this paper, a procedure based on efficient epsilon-constraint method and data envelopment analysis (DEA) is proposed for solving binary-state multi-objective reliability redundancy allocation series-parallel problem (MORAP). In first module, a set of qualified non-dominated solutions on Pareto front of binary-state MORAP is generated using an efficient epsilon-constraint method. In order to test the quality of generated non-dominated solutions in this module, a multi-start partial bound enumeration algorithm is also proposed for MORAP. The performance of both procedures is compared using different metrics on well-known benchmark instance. The statistical analysis represents that not only the proposed efficient epsilon-constraint method outperform the multi-start partial bound enumeration algorithm but also it improves the founded upper bound of benchmark instance. Then, in second module, a DEA model is supplied to prune the generated non-dominated solutions of efficient epsilon-constraint method. This helps reduction of non-dominated solutions in a systematic manner and eases the decision making process for practical implementations. - Highlights: ► A procedure based on efficient epsilon-constraint method and DEA was proposed for solving MORAP. ► The performance of proposed procedure was compared with a multi-start PBEA. ► Methods were statistically compared using multi-objective metrics.

BSDB: the Biomolecule Stretching Database

Science.gov (United States)

Cieplak, Marek; Sikora, Mateusz; Sulkowska, Joanna I.; Witkowski, Bartlomiej

2011-03-01

Despite more than a decade of experiments on single biomolecule manipulation, mechanical properties of only several scores of proteins have been measured. A characteristic scale of the force of resistance to stretching, Fmax , has been found to range between ~ 10 and 480 pN. The Biomolecule Stretching Data Base (BSDB) described here provides information about expected values of Fmax for, currently, 17 134 proteins. The values and other characteristics of the unfolding proces, including the nature of identified mechanical clamps, are available at www://info.ifpan.edu.pl/BSDB/. They have been obtained through simulations within a structure-based model which correlates satisfactorily with the available experimental data on stretching. BSDB also lists experimental data and results of the existing all-atom simulations. The database offers a Protein-Data-Bank-wide guide to mechano-stability of proteins. Its description is provided by a forthcoming Nucleic Acids Research paper. Supported by EC FUNMOL project FP7-NMP-2007-SMALL-1, and European Regional Development Fund: Innovative Economy (POIG.01.01.02-00-008/08).

The stretch reflex and the contributions of C David Marsden

Directory of Open Access Journals (Sweden)

Kalyan B Bhattacharyya

2017-01-01

Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

Stretched Exponential relaxation in pure Se glass

Science.gov (United States)

Dash, S.; Ravindren, S.; Boolchand, P.

A universal feature of glasses is the stretched exponential relaxation, f (t) = exp[ - t / τ ] β . The model of diffusion of excitations to randomly distributed traps in a glass by Phillips1 yields the stretched exponent β = d[d +2] where d, the effective dimensionality. We have measured the enthalpy of relaxation ΔHnr (tw) at Tg of Se glass in modulated DSC experiments as glasses age at 300K and find β = 0.43(2) for tw in the 0 8 months range. The observed β is in harmony with the trap model. The result is consistent with the growth of interchain structural correlations mediated by both long range (van der Waals forces) and short-range (covalent) interactions. A striking consequence of this relaxation is a narrowing of the glass transition width from 7.1°C to 1.4°C, and the ΔHnr term increasing from 0.21 cal/gm to 0.92 cal/gm. In bulk GexSe100-x glasses as x increases to 20%, the length of the polymeric Sen chains between the Ge-crosslinks decreases to n = 2. and the striking relaxation effects nearly vanish. J.C. Phillips, Rep.Prog.Phys. 59 , 1133 (1996). Supported by NSF Grant DMR 08-53957.

Static stretching does not alter pre and post-landing muscle activation

Directory of Open Access Journals (Sweden)

Moss Wesley R

2011-05-01

Full Text Available Abstract Background Static stretching may result in various strength and power deficiencies. Prior research has not determined, however, if static stretching causes a change in muscle activation during a functional task requiring dynamic stability. The purpose of this study was to determine if static stretching has an effect on mean pre and postlanding muscle (vastus medialis VM, vastus lateralis VL, medial hamstring MH, and biceps femoris BF activity. Methods 26 healthy, physically active subjects were recruited, from which 13 completed a 14-day static stretching regimen for the quadriceps and hamstrings. Using the data from the force plate and EMG readings, a mean of EMG amplitude was calculated for 150 msec before and after landing. Each trial was normalized to an isometric reference position. Means were calculated for the VM, VL, MH, and BF from 5 trials in each session. Measures were collected pre, immediately following the 1st stretching session, and following 2 weeks of stretching. Results A 14-day static stretching regimen resulted in no significant differences in pre or postlanding mean EMG amplitude during a drop landing either acutely or over a 14-day period. Conclusions Static stretching, done acutely or over a 14-day period does not result in measurable differences of mean EMG amplitude during a drop landing. Static stretching may not impede dynamic stability of joints about which stretched muscles cross.

The initial oxidation of epsilon-Fesub2Nsub1-x: growth kinetics

DEFF Research Database (Denmark)

Graat, Peter C.J.; Somers, Marcel A. J.; Mittemeijer, Eric J.

1999-01-01

The oxidation kinetics of epsilon-Fe2N1-x, subjected either to a sputter cleaning pretreatment or a sputter cleaning and an additional annealing pretreatment, at P-O2 = 1 x 10(-4) Pa and at temperatures ranging from 300 to 500 K, was investigated with ellipsometry. The initial oxidation rate of s...

Two-loop massive operator matrix elements for unpolarized heavy flavor production to O({epsilon})

Energy Technology Data Exchange (ETDEWEB)

Bierenbaum, I.; Bluemlein, J.; Klein, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation

2008-02-15

We calculate the O({alpha}{sup 2}{sub s}) massive operator matrix elements for the twist-2 operators, which contribute to the heavy flavor Wilson coefficients in unpolarized deeply inelastic scattering in the region Q{sup 2}>>m{sup 2}, up to the O({epsilon}) contributions. These terms contribute through the renormalization of the O({alpha}{sup 3}{sub s}) heavy flavor Wilson coefficients of the structure function F{sub 2}(x,Q{sup 2}). The calculation has been performed using light-cone expansion techniques without using the integration-by-parts method. We represent the individual Feynman diagrams by generalized hypergeometric structures, the {epsilon}-expansion of which leads to infinite sums depending on the Mellin variable N. These sums are finally expressed in terms of nested harmonic sums using the general summation techniques implemented in the Sigma package. (orig.)

Summary of the stretching tectonics research

International Nuclear Information System (INIS)

Yu Dagan

1994-01-01

The rise of stretching tectonics is established on the basis of recent structural geology theory, the establishment of metamorphic nucleus complex structural model on one hand plays an important promoting art to the development of stretching structure, on the other hand, it needs constant supplement and perfection in practice. Metamorphic nucleus complex is the carrier of comparatively deep geological information in vertical section of the crust and has wide distribution in the era of south China. Evidently, it can be taken as the 'key' to understanding the deep and studying the basement, Strengthening the study will play the important promoting role to the deep prospecting. The study of stretching tectonics is not only limited within the range of structure and metamorphism, but combine with the studies of sedimentation, magmatism, metamorphism and mineralization, thus form a new field of tectonic geology of self-developing system

Induction of CD3 delta epsilon omega by phorbol 12-myristate 13-acetate

DEFF Research Database (Denmark)

Vangsted, A; Neisig, A; Wallin, H

1993-01-01

The effect of phorbol 12-myristate 13-acetate (PMA) on the synthesis, assembly and processing of the components of the T cell receptor (TcR) was studied with special focus on the CD3 omega chain. Treatment of the human leukemic T cell line Jurkat with PMA increased the synthesis of the Ti alpha, CD......3 gamma and CG3 zeta chains two- to threefold and the synthesis of Ti beta and CD3 delta epsilon omega complexes five- to sevenfold as assessed by metabolic labeling, immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by scanning densitometry. The amount...... of TcR complexes expressed on the cell surface was decreased after 16 h of PMA treatment. Based on these results we propose a role of CD3 omega in retention of TcR complexes. From PMA-treated CEM cells more than 50-fold the amount of CD3 delta epsilon omega complexes was immunoprecipitated as compared...

The effects of the contract-relax-antagonist-contract form of proprioceptive neuromuscular facilitation stretching on postural stability.

Science.gov (United States)

Ryan, Edwin E; Rossi, Mark D; Lopez, Richard

2010-07-01

To investigate the effects of the contract-relax-antagonist-contract (CRAC) form of proprioceptive neuromuscular facilitation (PNF) stretching, with and without a warm-up, on postural stability. Thirty volunteers (15 men and 15 women, age: 25.17 +/- 5.4 years, height: 173.76 +/- 8.2 cm, and weight: 72.03 +/- 14.87 kg) were randomly assigned to 1 of 3 conditions: warm-up and stretch (WS), stretching only (SO), and a control condition (CON). Contract-relax-antagonist-contract PNF of the hamstrings, plantar flexors, and hip flexors was performed during WS and SO. A 6-minute treadmill warm-up was applied before CRAC in the WS condition. Measures of anterior/posterior and medial/lateral (M/L) postural stability were taken before and after treatment conditions. A 2 x 3 analysis of variance was used to assess for differences between conditions. Significance was set at p Contract-relax-antagonist-contract form of stretching is a useful protocol for improving M/L stability.

EFFECT OF DIFFERENT STRETCHING PROTOCOLS ON VERTICAL JUMP PERFORMANCE

Directory of Open Access Journals (Sweden)

Emre Serin

2018-04-01

Full Text Available This study aimed to examine the effect of different stretching exercises on vertical jump performance. A total of 14 national male athletes sporting in the elite level took part in the study. The age average of the participants was 20.25±1.03 year, the average height was 1.80±.08 m, the average body weight was 77.14±18.91 kg, average of sporting age was 9.87±3.31 year and the average number of participation in international games was 10.0±3.31. As stretching protocol: Method 1 (5 minutes of jogging and 2 minutes of active rest followed by Method 2 (static stretching for 4 different muscle groups 3 repetitions for 15 seconds of static stretching, rest for 10 seconds between groups and then consecutively, Method 3 (Dynamic stretching exercises with 3 repetitions for 15 seconds and 10 seconds rest between different muscle groups were applied in the study. The vertical jump performance before and after different stretching exercises of the participants was determined by means of the vertical jump test using the smart speed lite system. Before and after the training of all athletes, HR was recorded with a heart rate monitor (RS 800, Polar Vantage NV, Polar Electro Oy, Finland with 5 seconds intervals. Before the study, the chest band of the heartbeat monitor was placed on the chest of the athlete and the HR was recorded from the monitor. SPSS 15.0 statistical package program was used for evaluation and calculation of the data. In this study in addition to descriptive statistics (mean and standard deviation paired samples t-test was used to determine the difference between the vertical jump performance of the participants before and after different stretching exercises. As a result, this study showed that; applying the dynamic and static stretching exercises consecutively affected the vertical jump performance 4.5 cm positively (p<.05. It is suggested that different dynamic and static stretching exercises should be included in the vertical jump.

Gelatinized and nongelatinized corn starch/ poly(epsilon-caprolactone blends: characterization by rheological, mechanical and morphological properties

Directory of Open Access Journals (Sweden)

Derval S. Rosa

2004-09-01

Full Text Available Poly(epsilon-caprolactone/corn starch blends containing 25, 50 and 75 wt.% starch were prepared by mechanical processing and characterized by the melt flow index (MFI, tensile test and scanning electron microscopy (SEM. For comparison, starch was used in gelatinized and nongelatinized forms and was also characterized by viscography. The addition of starch to poly(epsilon-caprolactone reduced the MFI values, the tensile strength and the elongation at break, whereas the modulus increased. The reductions in the MFI and tensile properties were most evident when gelatinized starch was used. Viscography and SEM showed that starch was well gelatinized by the gelatinization process. Blends containing nongelatinized starch showed a good dispersion of starch but poor interfacial interactions.

epsilon-fructoselysine in urine of rats fed 14C-lysine-labeled casein browned by amino-carbonyl reaction

International Nuclear Information System (INIS)

Mori, Bunpei; Kojima, Kazumi; Saito, Susumu

1980-01-01

Radioactive substances were identified in urine of rats fed on browned casein, which had been labeled with U- 14 C-L-lysine. When browned casein was ingested by growing rats, high radioactivity was found in urine taken for 24 hr after feeding. Urinary recovery of radioactivity and specific radioactivity were about 9-times as high as those of the control. The radioactive substances were separated by Sephadex gel filtration and ion-exchange chromatography 75 - 83% of the total radioactivity was recovered in the first peak of Sephadex gel filtration. The material with radioactivity was separated into two fractions by ionexchange chromatography. The ratio of radioactivity of these peaks on the chromatogram was about 30 to 70. The main peak was identified as epsilon-fructoselysine with an amino acid autoanalyzer. Urinary epsilon-fructoselysine content of 24 hr after a single dose feeding of 600 mg browned labeled casein was 13 - 18 mg per head. The relationship between epsilon-fructoselysine content as an absorption delayed-material in the small intestinal lumen and the amount excreted in urine was explained in a scheme together with results from previous studies. (author)

A primary study on meridian-stretching of injected FDG using PET MPItool

International Nuclear Information System (INIS)

He Yijie; Tian Jiahe; Chen Yingmao; Yin Dayi; Zhang Jinming; Zhang Shuwen; Shao Mingzhe; Yao Shulin; Ding Weimin; Liu Zilai

2002-01-01

Objective: To show the images of tracer-stretching along the acupuncture meridian by use of PET with multipurpose imaging tool (MPItool's) fusion function. Methods: On 5 healthy volunteers, the authors measured the classical acupuncture points accurately with the biophysical measuring method. 18 F-fluorodeoxyglucose (FDG) was injected into the selected points, the others points along the same meridian were labelled with 18 F-FDG applied on the correspondent skin area of 2 . With the same body position, the transmission image and emission image was acquired respectively and fused with MPItool and its 3D display system. Results: The authors clearly showed not only the meridian-stretching images of the tracer, but also figured out the depth of the study points. The depth at SHANGJUXU point was about 3.8 cm and at ZUSANLI point was about 5,0 cm. The depths basically fit the classically documented ones of the correspondent acupuncture points. Conclusions: Using PET MPItool the authors preliminarily demonstrated that the tracer injected at the acupuncture point stretches along the correspondent meridian, and the depths of the meridian and the points (SHANGJUXU, ZUSANLI) detected are almost accordant with the classically documented ones

The influence of stretching on tensile strength and solubility of poly(vinyl alcohol) fibres

NARCIS (Netherlands)

Heikens, D.; Bleijenberg, A.C.A.M.; Hoppenbrouwers, J.J.M.; Barentsen, W.M.

1971-01-01

The strength of wet-spun poly(vinyl alcohol) (pva) fibres is given as function of bath-stretching, wet-stretching and hot-stretching. In the two equations derived for strength of wet-stretching and hot-stretching the complex influence of the bath-stretching and hot-stretching is demonstrated. The

Mechanical stretching effect on the actuator performance of cellulose electroactive paper

International Nuclear Information System (INIS)

Kim, Jung-Hwan; Yun, Ki-Ju; Kim, Joo-Hyung; Kim, Jaehwan

2009-01-01

The mechanical stretching effect on the actuating performance of electroactive cellulose paper (EAPap) was studied. A lattice elongation of cellulose fibrils due to in-plane tensile stress along the stretching direction was observed by the x-ray diffraction method. The shrinkage of the fibril diameter as a function of stretching ratio was confirmed by surface and cross-sectional images. While the actuator performance in terms of bending displacement decreased as the stretching ratio increased, the resonance frequency linearly increased as the stretching ratio increased, which was compared with the theoretical frequency data found from a cantilever beam model. The actuator efficiency was evaluated from the electrical input power consumption and the mechanical output power of an EAPap actuator. It was revealed that the stretching process increased the electro-mechanical efficiency of the EAPap actuator. The mechanism of the influence of the stretching effect on the performance of an EAPap actuator is discussed

Spontaneous bending of pre-stretched bilayers.

Science.gov (United States)

DeSimone, Antonio

2018-01-01

We discuss spontaneously bent configurations of pre-stretched bilayer sheets that can be obtained by tuning the pre-stretches in the two layers. The two-dimensional nonlinear plate model we use for this purpose is an adaptation of the one recently obtained for thin sheets of nematic elastomers, by means of a rigorous dimensional reduction argument based on the theory of Gamma-convergence (Agostiniani and DeSimone in Meccanica. doi:10.1007/s11012-017-0630-4, 2017, Math Mech Solids. doi:10.1177/1081286517699991, arXiv:1509.07003, 2017). We argue that pre-stretched bilayer sheets provide us with an interesting model system to study shape programming and morphing of surfaces in other, more complex systems, where spontaneous deformations are induced by swelling due to the absorption of a liquid, phase transformations, thermal or electro-magnetic stimuli. These include bio-mimetic structures inspired by biological systems from both the plant and the animal kingdoms.

Optofluidic time-stretch quantitative phase microscopy.

Science.gov (United States)

Guo, Baoshan; Lei, Cheng; Wu, Yi; Kobayashi, Hirofumi; Ito, Takuro; Yalikun, Yaxiaer; Lee, Sangwook; Isozaki, Akihiro; Li, Ming; Jiang, Yiyue; Yasumoto, Atsushi; Di Carlo, Dino; Tanaka, Yo; Yatomi, Yutaka; Ozeki, Yasuyuki; Goda, Keisuke

2018-03-01

Innovations in optical microscopy have opened new windows onto scientific research, industrial quality control, and medical practice over the last few decades. One of such innovations is optofluidic time-stretch quantitative phase microscopy - an emerging method for high-throughput quantitative phase imaging that builds on the interference between temporally stretched signal and reference pulses by using dispersive properties of light in both spatial and temporal domains in an interferometric configuration on a microfluidic platform. It achieves the continuous acquisition of both intensity and phase images with a high throughput of more than 10,000 particles or cells per second by overcoming speed limitations that exist in conventional quantitative phase imaging methods. Applications enabled by such capabilities are versatile and include characterization of cancer cells and microalgal cultures. In this paper, we review the principles and applications of optofluidic time-stretch quantitative phase microscopy and discuss its future perspective. Copyright © 2017 Elsevier Inc. All rights reserved.

ACUTE EFFECTS OF THREE DIFFERENT STRETCHING PROTOCOLS ON THE WINGATE TEST PERFORMANCE

Directory of Open Access Journals (Sweden)

Bruno L. Franco

2012-03-01

Full Text Available The purpose of this study was to examine the acute effects of different stretching exercises on the performance of the traditional Wingate test (WT. Fifteen male participants performed five WT; one for familiarization (FT, and the remaining four after no stretching (NS, static stretching (SS, dynamic stretching (DS, and proprioceptive neuromuscular facilitation (PNF. Stretches were targeted for the hamstrings, quadriceps, and calf muscles. Peak power (PP, mean power (MP, and the time to reach PP (TP were calculated. The MP was significantly lower when comparing the DS (7.7 ± 0.9 W/kg to the PNF (7.3 ± 0.9 W/kg condition (p < 0.05. For PP, significant differences were observed between more comparisons, with PNF stretching providing the lowest result. A consistent increase of TP was observed after all stretching exercises when compared to NS. The results suggest the type of stretching, or no stretching, should be considered by those who seek higher performance and practice sports that use maximal anaerobic power.

Eliminating electromechanical instability in dielectric elastomers by employing pre-stretch

International Nuclear Information System (INIS)

Jiang, Liang; Jerrams, Stephen; Betts, Anthony; Kennedy, David

2016-01-01

Electromechanical instability (EMI) is one of most common failure modes for dielectric elastomers (DEs). It has been reported that pre-stretching a DE sample can suppress EMI due to strain stiffening taking place for larger strains and a higher elastic modulus are achieved at high stretch ratios when a voltage is applied to the material. In this work, the influence of equi-biaxial stretch on DE secant modulus was studied using VHB 4910 and silicone rubber (SR) composites containing barium titanate (BaTiO 3 , BT) particles and also dopamine coated BT (DP-BT) particles. The investigation of equi-biaxial deformation and EMI failure for VHB 4910 was undertaken by introducing a voltage-stretch function. The results showed that EMI was suppressed by equi-biaxial pre-stretch for all the DEs fabricated and tested. The stiffening properties of the DE materials were also studied with respect to the secant modulus. Furthermore, a voltage-induced strain of above 200% was achieved for the polyacrylate film by applying a pre-stretch ratio of 2.0 without EMI occurring. However, a maximum voltage-induced strain in the polyacrylate film of 78% was obtained by the SR/20 wt% DP-BT composite for a lower applied pre-stretch ratio of 1.6 and again EMI was eliminated. (paper)

Lineage determination of CD7+ CD5- CD2- and CD7+ CD5+ CD2- lymphoblasts: studies on phenotype, genotype, and gene expression of myeloperoxidase, CD3 epsilon, and CD3 delta.

Science.gov (United States)

Yoneda, N; Tatsumi, E; Teshigawara, K; Nagata, S; Nagano, T; Kishimoto, Y; Kimura, T; Yasunaga, K; Yamaguchi, N

1994-04-01

The gene expression of myeloperoxidase (MPO), CD3 epsilon, and CD3 delta molecules, the gene rearrangement of T-cell receptor (TCR) delta, gamma, and beta and immunoglobulin heavy (IgH) chain, and the expression of cell-surface antigens were investigated in seven cases of CD7+ CD5- CD2- and four cases of CD7+ CD5+ CD2- acute lymphoblastic leukemia or lymphoblastic lymphoma (ALL/LBL) blasts, which were negative for cytochemical myeloperoxidase (cyMPO). More mature T-lineage blasts were also investigated in a comparative manner. In conclusion, the CD7+ CD5- CD2- blasts included four categories: undifferentiated blasts without lineage commitment, T-lineage blasts, T-/myeloid lineage blasts, and cyMPO-negative myeloblasts. The CD7+ CD5+ CD2- blasts included two categories; T-lineage and T-/myeloid lineage blasts. The 11 cases were of the germ-line gene (G) for TCR beta and IgH. Four cases were G for TCR delta and TCR gamma. The others were of the monoclonally rearranged gene (R) for TCR delta and G for TCR gamma or R for both TCR delta and TCR gamma. The expression or in vitro induction of CD13 and/or CD33 antigens correlated with the immaturity of these neoplastic T cells, since it was observed in all 11 CD7+ CD5- CD2- and CD7+ CD5+ CD2-, and some CD7+ CD5+ CD2+ (CD3- CD4- CD8-) cases, but not in CD3 +/- CD4+ CD8+ or CD3+ CD4+ CD8- cases. CD3 epsilon mRNA, but not CD3 delta mRNA, was detected in two CD7+ CD5- CD2- cases, while mRNA of neither of the two CD3 molecules was detected in the other tested CD7+ CD5- CD2- cases. In contrast, mRNA of both CD3 epsilon and CD3 delta were detected in all CD7+ CD5+ CD2- cases, indicating that CD7+ CD5- CD2- blasts at least belong to T-lineage. The blasts of two CD7+ CD5- CD2- cases with entire germ-line genes and without mRNA of the three molecules (MPO, CD3 epsilon, and CD3 delta) were regarded as being at an undifferentiated stage prior to their commitment to either T- or myeloid-lineage. The co-expression of the genes of MPO

Acute effect of different stretching methods on isometric muscle strength

Directory of Open Access Journals (Sweden)

Gabriel Vasconcellos de Lima Costa e Silva

2014-03-01

This study investigated the acute effect of static stretching methods (SS and proprioceptive neuromuscular facilitation (PNF on the static muscle strength (SMS. Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a hand grip without stretching; b hand grip preceded by static stretching of wrist flexors muscles; c hand grip preceded by PNF stretching of wrist flexors muscles. The Shapiro-Wilk test verified the normality of data, and a one-way ANOVA with repeated measures, followed by Tukey’s post hoc test, evaluated the differences between the groups. The significance was set at p 0.05. In conclusion, both stretching methods had caused negative effects on isometric strength, reducing its levels.

Upper Limb Static-Stretching Protocol Decreases Maximal Concentric Jump Performance

Directory of Open Access Journals (Sweden)

Paulo H. Marchetti

2014-12-01

Full Text Available The purpose of the present study was to evaluate the acute effects of an upper limb static-stretching (SS protocol on the maximal concentric jump performance. We recruited 25 young healthy, male, resistance trained individuals (stretched group, n = 15 and control group, n = 10 in this study. The randomized between group experimental protocol consisted of a three trials of maximal concentric jump task, before and after a SS of the upper limb. Vertical ground reaction forces (vGRF and surface electromyography (sEMG of both gastrocnemius lateralis (GL and vastus lateralis (VL were acquired. An extensive SS was employed consisting of ten stretches of 30 seconds, with 15 seconds of rest, and 70-90% of the point of discomfort (POD. ANOVA (2x2 (group x condition was used for shoulder joint range of motion (ROM, vGRF and sEMG. A significant interaction for passive ROM of the shoulder joint revealed significant increases between pre- and post-SS protocol (p < 0.001. A significant interaction demonstrated decreased peak force and an increased peak propulsion duration between pre- and post-stretching only for stretch group (p = 0.021, and p = 0.024, respectively. There was a significant main effect between groups (stretch and control for peak force for control group (p = 0.045. Regarding sEMG variables, there were no significant differences between groups (control versus stretched or condition (pre-stretching versus post-stretching for the peak amplitude of RMS and IEMG for both muscles (VL and GL. In conclusion, an acute extensive SS can increase the shoulder ROM, and negatively affect both the propulsion duration and peak force of the maximal concentric jump, without providing significant changes in muscle activation.

Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

Directory of Open Access Journals (Sweden)

Arthur Leloup

2017-10-01

Full Text Available Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10% than muscular arteries (2%. As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC. The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels were measured. As compared with static or cyclic stretch at low amplitude (<10 mN or low frequency (0.1 Hz, cyclic stretch at physiological amplitude (>10 mN and frequency (1–10 Hz caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME, physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and

Guidelines for Stretch Flanging Advanced High Strength Steels

International Nuclear Information System (INIS)

Sriram, S.; Chintamani, J.

2005-01-01

Advanced High Strength Steels (AHSS) are currently being considered for use in closure and structural panels in the automotive industry because of their high potential for affordable weight reduction and improved performance. AHSS such as dual phase steels are currently being used in some vehicle platforms. From a manufacturing perspective, stretch flanging during stamping is an important deformation mode requiring careful consideration of geometry and the die process. This paper presents some geometric and process guidelines for stretch flanging AHSS. Hole expansion experiments were conducted to determine the failure limit for a sheared edge condition. Effects of punching clearance, prestrain and prior strain path on hole expansion were explored in these experiments. In addition, dynamic explicit FE calculations using LS-DYNA were also conducted for a typical stretch flange by varying some key geometric parameters. The experimental and FEA results were then analyzed to yield process and geometric guidelines to enable successful stretch flanging of AHSS

Stretching skeletal muscle: chronic muscle lengthening through sarcomerogenesis.

Directory of Open Access Journals (Sweden)

Alexander M Zöllner

Full Text Available Skeletal muscle responds to passive overstretch through sarcomerogenesis, the creation and serial deposition of new sarcomere units. Sarcomerogenesis is critical to muscle function: It gradually re-positions the muscle back into its optimal operating regime. Animal models of immobilization, limb lengthening, and tendon transfer have provided significant insight into muscle adaptation in vivo. Yet, to date, there is no mathematical model that allows us to predict how skeletal muscle adapts to mechanical stretch in silico. Here we propose a novel mechanistic model for chronic longitudinal muscle growth in response to passive mechanical stretch. We characterize growth through a single scalar-valued internal variable, the serial sarcomere number. Sarcomerogenesis, the evolution of this variable, is driven by the elastic mechanical stretch. To analyze realistic three-dimensional muscle geometries, we embed our model into a nonlinear finite element framework. In a chronic limb lengthening study with a muscle stretch of 1.14, the model predicts an acute sarcomere lengthening from 3.09[Formula: see text]m to 3.51[Formula: see text]m, and a chronic gradual return to the initial sarcomere length within two weeks. Compared to the experiment, the acute model error was 0.00% by design of the model; the chronic model error was 2.13%, which lies within the rage of the experimental standard deviation. Our model explains, from a mechanistic point of view, why gradual multi-step muscle lengthening is less invasive than single-step lengthening. It also explains regional variations in sarcomere length, shorter close to and longer away from the muscle-tendon interface. Once calibrated with a richer data set, our model may help surgeons to prevent muscle overstretch and make informed decisions about optimal stretch increments, stretch timing, and stretch amplitudes. We anticipate our study to open new avenues in orthopedic and reconstructive surgery and enhance

Filament stretching rheometer: inertia compensation revisited

DEFF Research Database (Denmark)

Szabo, Peter; McKinley, Gareth H.

2003-01-01

The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end of the e......The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end...

Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

Directory of Open Access Journals (Sweden)

Lynn Bar-On

Full Text Available The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01. The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between

Dynamics of the OH stretching mode in crystalline Ba(ClO4)2.3H2O

Science.gov (United States)

Hutzler, Daniel; Brunner, Christian; Petkov, Petko St.; Heine, Thomas; Fischer, Sighart F.; Riedle, Eberhard; Kienberger, Reinhard; Iglev, Hristo

2018-02-01

The vibrational dynamics of the OH stretching mode in Ba(ClO4)2 trihydrate are investigated by means of femtosecond infrared spectroscopy. The sample offers plane cyclic water trimers in the solid phase that feature virtually no hydrogen bond interaction between the water molecules. Selective excitation of the symmetric and asymmetric stretching leads to fast population redistribution, while simultaneous excitation yields quantum beats, which are monitored via a combination tone that dominates the overtone spectrum. The combination of steady-state and time-resolved spectroscopy with quantum chemical simulations and general theoretical considerations gives indication of various aspects of symmetry breakage. The system shows a joint population lifetime of 8 ps and a long-lived coherence between symmetric and asymmetric stretching, which decays with a time constant of 0.6 ps.

The epsilon regime of chiral perturbation theory with Wilson-type fermions

Energy Technology Data Exchange (ETDEWEB)

Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Shindler, A. [Liverpool Univ. (United Kingdom). Theoretical Physics Division

2009-11-15

In this proceeding contribution we report on the ongoing effort to simulate Wilson-type fermions in the so called epsilon regime of chiral perturbation theory (cPT).We present results for the chiral condensate and the pseudoscalar decay constant obtained with Wilson twisted mass fermions employing two lattice spacings, two different physical volumes and several quark masses. With this set of simulations we make a first attempt to estimate the systematic uncertainties. (orig.)

The epsilon regime of chiral perturbation theory with Wilson-type fermions

International Nuclear Information System (INIS)

Jansen, K.; Shindler, A.

2009-11-01

In this proceeding contribution we report on the ongoing effort to simulate Wilson-type fermions in the so called epsilon regime of chiral perturbation theory (cPT).We present results for the chiral condensate and the pseudoscalar decay constant obtained with Wilson twisted mass fermions employing two lattice spacings, two different physical volumes and several quark masses. With this set of simulations we make a first attempt to estimate the systematic uncertainties. (orig.)

Phenomenological quantum electrodynamics when epsilonμ=l: Theory and some applications including the Casimir effect

International Nuclear Information System (INIS)

Brevik, I.

1983-01-01

The canonical quantum theory for an electromagnetic field within an isotropic nondispersive medium, whose permittivity, epsilon, and permeability μ satisfy the condition epsilonμ=1, is developed. This condition is found to simplify the electromagnetic formalism considerably and is of interest not only to quantum electrodynamics (QED) but also to quantum chromodynamics (QDC) in view of the formal analogy existing between these two theories to the zero-order in the gauge coupling constant. After giving a survey of the general formalism, this paper discusses appropriate modifications of known experiments in optics: the Ashkin-Dziedzic pressure experiment (1973), the Barlow experiment (1912), and the levitation experiment of Ashkin (1970) and others. Finally, a calculation is given of Casimir (i.e., zero-point) surface force acting on one of two spherical interfaces separating three media from each other, under certain simplifying conditions

Effect of hydrostatic pressure on phase transformations in Kh17N8 steel during deformation

International Nuclear Information System (INIS)

Eshchenko, R.N.; Teplov, V.A.

1984-01-01

The phase composition and structure of Kh17N8 steel strained to different degrees under atmospheric pressure and 1700 MPa are investigated. It has been found that deformation at 1700 MPa causes α and epsilon-martensite formation, the same deformation under atmospheric pressure - only α-martensite formation. The amount of the formed α-martensite is not changed with application of hydrostatic pressure. Electron-microscopic observations have shown that the dispersion of α-martensite formed under pressure is higher than in the absence of pressure; no interconnection in formation of α and epsilon-martensite in samples strained under pressure has been observed

A novel optimization algorithm based on epsilon constraint-RBF neural network for tuning PID controller in decoupled HVAC system

International Nuclear Information System (INIS)

Attaran, Seyed Mohammad; Yusof, Rubiyah; Selamat, Hazlina

2016-01-01

Highlights: • Decoupling of a heating, ventilation, and air conditioning system is presented. • RBF models were identified by Epsilon constraint method for temperature and humidity. • Control settings derived from optimization of the decoupled model. • Epsilon constraint-RBF based on PID controller was implemented to keep thermal comfort and minimize energy. • Enhancements of controller parameters of the HVAC system are desired. - Abstract: The energy efficiency of a heating, ventilating and air conditioning (HVAC) system optimized using a radial basis function neural network (RBFNN) combined with the epsilon constraint (EC) method is reported. The new method adopts the advanced algorithm of RBFNN for the HVAC system to estimate the residual errors, increase the control signal and reduce the error results. The objective of this study is to develop and simulate the EC-RBFNN for a self tuning PID controller for a decoupled bilinear HVAC system to control the temperature and relative humidity (RH) produced by the system. A case study indicates that the EC-RBFNN algorithm has a much better accuracy than optimization PID itself and PID-RBFNN, respectively.

Stretching single fibrin fibers hampers their lysis.

Science.gov (United States)

Li, Wei; Lucioni, Tomas; Li, Rongzhong; Bonin, Keith; Cho, Samuel S; Guthold, Martin

2017-09-15

Blood clots, whose main structural component is a mesh of microscopic fibrin fibers, experience mechanical strain from blood flow, clot retraction and interactions with platelets and other cells. We developed a transparent, striated and highly stretchable substrate made from fugitive glue (a styrenic block copolymer) to investigate how mechanical strain affects lysis of single, suspended fibrin fibers. In this suspended fiber assay, lysis manifested itself by fiber elongation, thickening (disassembly), fraying and collapse. Stretching single fibrin fibers significantly hampered their lysis. This effect was seen in uncrosslinked and crosslinked fibers. Crosslinking (without stretching) also hampered single fiber lysis. Our data suggest that strain is a novel mechanosensitive factor that regulates blood clot dissolution (fibrinolysis) at the single fiber level. At the molecular level of single fibrin molecules, strain may distort, or hinder access to, plasmin cleavage sites and thereby hamper lysis. Fibrin fibers are the major structural component of a blood clot. We developed a highly stretchable substrate made from fugitive glue and a suspended fibrin fiber lysis assay to investigate the effect of stretching on single fibrin fibers lysis. The key findings from our experiments are: 1) Fibers thicken and elongate upon lysis; 2) stretching strongly reduces lysis; 3) this effect is more pronounced for uncrosslinked fibers; and 4) stretching fibers has a similar effect on reducing lysis as crosslinking fibers. At the molecular level, strain may distort plasmin cleavage sites, or restrict access to those sites. Our results suggest that strain may be a novel mechanobiological factor that regulates fibrinolysis. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of sterilisation by high-energy radiation on biomedical poly-(epsilon-caprolactone)/hydroxyapatite composites.

Science.gov (United States)

Di Foggia, Michele; Corda, Ugo; Plescia, Elena; Taddei, Paola; Torreggiani, Armida

2010-06-01

The effects of a high energy sterilization treatment on poly-epsilon-caprolactone/carbonated hydroxyapatite composites have been investigated. Poly-epsilon-caprolactone is a biodegradable polymer used as long-term bioresorbable scaffold for bone tissue engineering and carbonated hydroxyapatite is a bioactive material able to promote bone growth. The composites were gamma-irradiated in air or under nitrogen atmosphere with doses ranging from 10 to 50 kGy (i.e. to a value higher than that recommended for sterilization). The effects of the irradiation treatment were evaluated by vibrational spectroscopy (IR and Raman spectroscopies) coupled to thermal analysis (Differential Scanning Calorimetry and Thermogravimetry) and Electron Paramagnetic Resonance spectroscopy. Irradiation with the doses required for sterilization induced acceptable structural changes and damaging effects: only a very slight fragmentation of the polymeric chains and some defects in the inorganic component were observed. Moreover, the radiation sensitivity of the composites proved almost the same under the two different atmospheres.

Characterizing the stretch-flangeability of hot rolled multiphase steels

International Nuclear Information System (INIS)

Pathak, N.; Butcher, C.; Worswick, M.; Gao, J.

2013-01-01

Hole expansion tests are commonly used to characterize the edge stretching limit of a material. Traditionally, a conical punch is used to expand a punched hole until a through-thickness crack appears. However, many automotive stretch flanging operations involve in-plane edge stretching that is best captured with a flat punch. In this paper, hole expansion tests were carried out on two different hot-rolled multiphase steels using both flat and conical punches. The fracture mechanisms for both punch types were investigated using scanning electron microscopy (SEM)

Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force

Directory of Open Access Journals (Sweden)

Leyla Alizadeh Ebadi

2018-03-01

Full Text Available The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles’ isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A 5 min jogging; (B 5 min jogging followed by 15 s static stretching; (C 5 min jogging followed by 30 s static stretching; (D 5 min jogging, followed by static stretching for 45 s. Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

The influence of foot position on stretching of the plantar fascia.

Science.gov (United States)

Flanigan, Ryan M; Nawoczenski, Deborah A; Chen, Linlin; Wu, Hulin; DiGiovanni, Benedict F

2007-07-01

A recent study found nonweightbearing stretching exercises specific to the plantar fascia to be superior to the standard program of weightbearing Achilles tendon-stretching exercises in patients with chronic plantar fasciitis. The present study used a cadaver model to demonstrate the influence of foot and ankle position on stretching of the plantar fascia. Twelve fresh-frozen lower-leg specimens were tested in 15 different configurations representing various combinations of ankle and metatarsophalangeal (MTP) joint dorsiflexion, midtarsal transverse plane abduction and adduction, and forefoot varus and valgus. Measurements were recorded by a differential variable reluctance transducer (DVRT) implanted into the medial band of the plantar fascia, and primary measurement was a percent deformation of the plantar fascia (stretch) with respect to a reference position (90 degrees ankle dorsiflexion, 0 degrees midtarsal and forefoot orientation, and 0 degrees MTP dorsiflexion). Ankle and MTP joint dorsiflexion produced a significant increase (14.91%) in stretch compared to the position of either ankle dorsiflexion alone (9.31% increase, p plantar fascia tissue-specific stretching exercises and lends support to the use of ankle and MTP joint dorsiflexion when employing stretching protocols for nonoperative treatment in patients with chronic proximal plantar fasciitis.

1/N expansions in P(phi2)sub(4-epsilon) theory. Pt. 1

International Nuclear Information System (INIS)

Symanzik, K.

1977-01-01

1/N expansions in O(N) invariant one-scale massless P(phi vector 2 )4-epsilon theory are derived for finite and infinite bare coupling constant. Since superficially relevant (phi vector 2 )sup(m), m >= 3, interactions can hereby be transformed into interactions irrelevant for large-distance behaviour, the scale-invariant limit theory is universal. (orig.) [de

Interset stretching does not influence the kinematic profile of consecutive bench-press sets.

Science.gov (United States)

García-López, David; Izquierdo, Mikel; Rodríguez, Sergio; González-Calvo, Gustavo; Sainz, Nuria; Abadía, Olaia; Herrero, Azael J

2010-05-01

This study was undertaken to examine the role of interset stretching on the time course of acceleration portion AP and mean velocity profile during the concentric phase of 2 bench-press sets with a submaximal load (60% of the 1 repetition maximum). Twenty-five college students carried out, in 3 different days, 2 consecutive bench-press sets leading to failure, performing between sets static stretching, ballistic stretching, or no stretching. Acceleration portion and lifting velocity patterns of the concentric phase were not altered during the second set, regardless of the stretching treatment performed. However, when velocity was expressed in absolute terms, static stretching reduced significantly (p velocity during the second set compared to the first one. Therefore, if maintenance of a high absolute velocity over consecutive sets is important for training-related adaptations, static stretching should be avoided or replaced by ballistic stretching.

Application of low Reynolds number k-{epsilon} turbulence models to the study of turbulent wall jets

Energy Technology Data Exchange (ETDEWEB)

Kechiche, Jamel; Mhiri, Hatem [Laboratoire de Mecanique des Fluides et Thermique, Ecole Nationale d' Ingenieurs de Monastir, route de Ouardanine, 5000, Monastir (Tunisia); Le Palec, Georges; Bournot, Philippe [Institut de Mecanique de Marseille, 60, rue Joliot-Curie, Technopole de Chateau-Gombert, 13453 cedex 13, Marseille (France)

2004-02-01

In this work, we use closure models called ''low Reynolds number k-{epsilon} models'', which are self-adapting ones using different damping functions, in order to explore the computed behavior of a turbulent plane two-dimensional wall jets. In this study, the jet may be either isothermal or submitted to various wall boundary conditions (uniform temperature or a uniform heat flux) in forced convection regime. A finite difference method, using a staggered grid, is employed to solve the coupled governing equations with the inlet and the boundary conditions. The predictions of the various low Reynolds number k-{epsilon} models with standard or modified C{sub {mu}} adopted in this work were presented and compared with measurements and numerical results found in the literature. (authors)

Numerical and experimental investigation of stretch-flange forming

International Nuclear Information System (INIS)

Cinotti, N.; Shakeri, H.R.; Worswick, M.J.; Truttmann, S.; Finn, M.J.; Jain, M.; Lloyd, D.J.

2000-01-01

Simulations of stretch flange forming operations are undertaken using explicit dynamic finite element calculations incorporating anisotropic yield criteria. Simple circular stretch flanges utilizing a single circular punch to expand the cut-out were considered. Experiments were performed using 101mm diameter tooling on AA 5754 and AA 5182 aluminum alloy sheets, with varying cut-out and gauge size. Metallurgical aspects of the formability of these aluminum alloys and damage mechanisms were studied. Both optical and Scanning Electron Microscopy (SEM) were used to study ductile fracture behaviour in these materials during the forming operation. The limit strains obtained from the circular stretch flange formability experiments are compared to forming limit diagram (FLD) data from hemispherical dome specimens. (author)

Stretch activates myosin light chain kinase in arterial smooth muscle

International Nuclear Information System (INIS)

Barany, K.; Rokolya, A.; Barany, M.

1990-01-01

Stretching of porcine carotid arterial muscle increased the phosphorylation of the 20 kDa myosin light chain from 0.23 to 0.68 mol [32P]phosphate/mol light chain, whereas stretching of phorbol dibutyrate treated muscle increased the phosphorylation from 0.30 to 0.91 mol/mol. Two-dimensional gel electrophoresis followed by two-dimensional tryptic phosphopeptide mapping was used to identify the enzyme involved in the stretch-induced phosphorylation. Quantitation of the [32P]phosphate content of the peptides revealed considerable light chain phosphorylation by protein kinase C only in the phorbol dibutyrate treated arterial muscle, whereas most of the light chain phosphorylation was attributable to myosin light chain kinase. Upon stretch of either the untreated or treated muscle, the total increment in [32P]phosphate incorporation into the light chain could be accounted for by peptides characteristic for myosin light chain kinase catalyzed phosphorylation, demonstrating that the stretch-induced phosphorylation is caused by this enzyme exclusively

The occultation of Epsilon Geminorum by Mars - Analysis of McDonald data. [turbulent scintillation in light curves

Science.gov (United States)

Africano, J.; De Vaucouleurs, G.; Evans, D. S.; Finkel, B. E.; Nather, R. E.; Palm, C.; Silverberg, E.; Wiant, J.; Hubbard, W. B.; Jokipii, J. R.

1977-01-01

An analysis of observations of the occultation of Epsilon Gem by Mars on April 8, 1976, is presented. The data were obtained by three neighboring telescopes at McDonald Observatory. Intensity fluctuations on time scales of the order of 100 ms were observed simultaneously at the three telescopes. As the observations compare well with predictions of turbulent scintillation theory, it is concluded that such fluctuations were probably largely the effect of stellar scintillations in the Martian atmosphere. The stellar diameter is included as a parameter in the theory but in a way which differs from previously published interpretations of occultations of extended sources by planetary atmospheres. Scintillations govern the experimental uncertainty in the deduction of the scale height of the high Martian atmosphere. A density scale height of 9.9 + or - 2.5 km is obtained at an altitude of 74 + or - 8 km above the mean surface. For CO 2 gas, this result corresponds to a temperature of 190 + or - 50 K.

Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

Science.gov (United States)

Olson, Sandra

2011-01-01

To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

Stretch-sensitive paresis and effort perception in hemiparesis.

Science.gov (United States)

Vinti, Maria; Bayle, Nicolas; Hutin, Emilie; Burke, David; Gracies, Jean-Michel

2015-08-01

In spastic paresis, stretch applied to the antagonist increases its inappropriate recruitment during agonist command (spastic co-contraction). It is unknown whether antagonist stretch: (1) also affects agonist recruitment; (2) alters effort perception. We quantified voluntary activation of ankle dorsiflexors, effort perception, and plantar flexor co-contraction during graded dorsiflexion efforts at two gastrocnemius lengths. Eighteen healthy (age 41 ± 13) and 18 hemiparetic (age 54 ± 12) subjects performed light, medium and maximal isometric dorsiflexion efforts with the knee flexed or extended. We determined dorsiflexor torque, Root Mean Square EMG and Agonist Recruitment/Co-contraction Indices (ARI/CCI) from the 500 ms peak voluntary agonist recruitment in a 5-s maximal isometric effort in tibialis anterior, soleus and medial gastrocnemius. Subjects retrospectively reported effort perception on a 10-point visual analog scale. During gastrocnemius stretch in hemiparetic subjects, we observed: (1) a 25 ± 7 % reduction of tibialis anterior voluntary activation (maximum reduction 98 %; knee extended vs knee flexed; p = 0.007, ANOVA); (2) an increase in dorsiflexion effort perception (p = 0.03, ANCOVA). Such changes did not occur in healthy subjects. Effort perception depended on tibialis anterior recruitment only (βARI(TA) = 0.61, p hemiparesis, voluntary ability to recruit agonist motoneurones is impaired--sometimes abolished--by antagonist stretch, a phenomenon defined here as stretch-sensitive paresis. In addition, spastic co-contraction increases effort perception, an additional incentive to evaluate and treat this phenomenon.

Acute anal stretch inhibits NMDA-dependent pelvic-urethra reflex potentiation via spinal GABAergic inhibition in anesthetized rats.

Science.gov (United States)

Chen, Sung-Lang; Huang, Yu-Hui; Kao, Yu-Lin; Chen, Gin-Den; Cheng, Chen-Li; Peng, Hsien-Yu; Liao, Jiuan-Miaw; Huang, Pei-Chen; Tsai, Shih-Jei; Lin, Tzer-Bin

2008-10-01

The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram activity evoked by the pelvic afferent stimulation. Test stimulation (1 stimulation/30 s) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg iv). On the other hand, the repetitive stimulation (1 stimulation/1 s) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal 6-cyano-7-nitroquinoxaline-2,4-dione (a glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionat receptor antagonist, 100 microM, 10 microl) and d-2-amino-5-phosphonovalerate [a glutamatergic N-methyl-D-aspartate (NMDA) antagonist, 100 microM, 10 microl]. Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, whereas distances of 8 mm attenuated and 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 microM, 10 microl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline [gamma-aminobutyric acid (GABA) A receptor antagonist, 100 microM, 10 microl] but not hydroxysaclofen (GABAB receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All of the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.

Dipion decay modes of the UPSILON family from a universal epsilon coupling

International Nuclear Information System (INIS)

Coffou, E.; Martinis, M.; Mikuta-Martinis, V.

1986-01-01

In the framework of a universal-epsilon-coupling scheme we obtain predictions for the decay rates of UPSILON'→UPSILONππ, UPSILON''→UPSILONππ, and UPSILON''→UPSILON'ππ in agreement with CLEO and CUSB measurements. We also predict the shape of the dipion mass distribution for these transitions. The shape predicted for UPSILON'→UPSILONππ is found to be in excellent agreement with experiment

Effect of spinal manipulative therapy with stretching compared with stretching alone on full-swing performance of golf players: a randomized pilot trial☆

Science.gov (United States)

Costa, Soraya M.V.; Chibana, Yumi E.T.; Giavarotti, Leandro; Compagnoni, Débora S.; Shiono, Adriana H.; Satie, Janice; Bracher, Eduardo S.B.

2009-01-01

Abstract Objective There has been a steady growth of chiropractic treatment using spinal manipulative therapy (SMT) that aims to increase the performance of athletes in various sports. This study evaluates the effect of SMT by chiropractors on the performance of golf players. Methods Golfers of 2 golf clubs in São Paulo, Brazil, participated in this study. They were randomized to 1 of 2 groups: Group I received a stretch program, and group II received a stretch program in addition to SMT. Participants in both groups performed the same standardized stretching program. Spinal manipulative therapy to dysfunctional spinal segments was performed on group II only. All golfers performed 3 full-swing maneuvers. Ball range was considered as the average distance for the 3 shots. Treatment was performed after the initial measurement, and the same maneuvers were performed afterward. Each participant repeated these procedures for a 4-week period. Student t test, Mann-Whitney nonparametric test, and 1-way analysis of variance for repeated measures with significance level of 5% were used to analyze the study. Results Forty-three golfers completed the protocol. Twenty participants were allocated to group I and 23 to group II. Average age, handicap, and initial swing were comparable. No improvement of full-swing performance was observed during the 4 sessions on group I (stretch only). An improvement was observed at the fourth session of group II (P = .005); when comparing the posttreatment, group II had statistical significance at all phases (P = .003). Conclusions Chiropractic SMT in association with muscle stretching may be associated with an improvement of full-swing performance when compared with muscle stretching alone. PMID:19948307

Ca2+ influx and ATP release mediated by mechanical stretch in human lung fibroblasts

International Nuclear Information System (INIS)

Murata, Naohiko; Ito, Satoru; Furuya, Kishio; Takahara, Norihiro; Naruse, Keiji; Aso, Hiromichi; Kondo, Masashi; Sokabe, Masahiro; Hasegawa, Yoshinori

2014-01-01

Highlights: • Uniaxial stretching activates Ca 2+ signaling in human lung fibroblasts. • Stretch-induced intracellular Ca 2+ elevation is mainly via Ca 2+ influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca 2+ influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca 2+ concentration ([Ca 2+ ] i ) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca 2+ ] i transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca 2+ ] i . The stretch-induced [Ca 2+ ] i elevation was attenuated in Ca 2+ -free solution. In contrast, the increase of [Ca 2+ ] i by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd 3+ , ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca 2+ ] i elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca 2+ influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP

Investigating the role of musical genre in human perception of music stretching resistance

OpenAIRE

Chen, Jun; Wang, Chaokun

2017-01-01

To stretch a music piece to a given length is a common demand in people's daily lives, e.g., in audio-video synchronization and animation production. However, it is not always guaranteed that the stretched music piece is acceptable for general audience since music stretching suffers from people's perceptual artefacts. Over-stretching a music piece will make it uncomfortable for human psychoacoustic hearing. The research on music stretching resistance attempts to estimate the maximum stretchab...

Equibiaxial cyclic stretch stimulates fibroblasts to rapidly remodel fibrin.

Science.gov (United States)

Balestrini, Jenna Leigh; Billiar, Kristen Lawrence

2006-01-01

Understanding the effects of the mechanical environment on wound healing is critical for developing more effective treatments to reduce scar formation and contracture. The aim of this study was to investigate the effects of dynamic mechanical stretch on cell-mediated early wound remodeling independent of matrix alignment which obscures more subtle remodeling mechanisms. Cyclic equibiaxial stretch (16% stretch at 0.2 Hz) was applied to fibroblast-populated fibrin gel in vitro wound models for eight days. Compaction, density, tensile strength, and collagen content were quantified as functional measures of remodeling. Stretched samples were approximately ten times stronger, eight-fold more dense, and eight times thinner than statically cultured samples. These changes were accompanied by a 15% increase in net collagen but no significant differences in cell number or viability. When collagen crosslinking was inhibited in stretched samples, the extensibility increased and the strength decreased. The apparent weakening was due to a reduction in compaction rather than a decrease in ability of the tissue to withstand tensile forces. Interestingly, inhibiting collagen crosslinking had no measurable effects on the statically cultured samples. These results indicate that amplified cell-mediated compaction and even a slight addition in collagen content play substantial roles in mechanically induced wound strengthening. These findings increase our understanding of how mechanical forces guide the healing response in skin, and the methods employed in this study may also prove valuable tools for investigating stretch-induced remodeling of other planar connective tissues and for creating mechanically robust engineered tissues.

Early effect of ApoE-epsilon 4 allele on cognitive results in a group of highly performing subjects: the EVA study. Etude sur le Vieillissement Artériel.

Science.gov (United States)

Berr, C; Dufouil, C; Brousseau, T; Richard, F; Amouyel, P; Marceteau, E; Alpérovitch, A

1996-10-25

We examined the association between apolipoprotein E (ApoE) epsilon 4 allele and cognitive performances in a population sample of 1174 high functioning volunteers aged 59-71 years. The neuropsychological battery included the Mini Mental State Examination (MMSE) and nine tests assessing visual attention, verbal memory, visual processing, logical reasoning, psychomotor rapidity, visual memory, auditory attention and verbal fluency. The ratio of genotypes with zero, one or two epsilon 4 alleles was 70.6%, 21.4% and 1.9%, respectively. The epsilon 4 allele was significantly associated with lower scores for visual attention, psychomotor rapidity and MMSE. In the best performer subgroup (MMSE score above 25, n = 1028), all relationships persisted. Our findings demonstrate that the ApoE-epsilon 4 allele is early associated with low normal cognitive performances in areas which are not specifically affected at the subclinical onset of dementia.

Lewis lung carcinoma regulation of mechanical stretch-induced protein synthesis in cultured myotubes.

Science.gov (United States)

Gao, Song; Carson, James A

2016-01-01

Mechanical stretch can activate muscle and myotube protein synthesis through mammalian target of rapamycin complex 1 (mTORC1) signaling. While it has been established that tumor-derived cachectic factors can induce myotube wasting, the effect of this catabolic environment on myotube mechanical signaling has not been determined. We investigated whether media containing cachectic factors derived from Lewis lung carcinoma (LLC) can regulate the stretch induction of myotube protein synthesis. C2C12 myotubes preincubated in control or LLC-derived media were chronically stretched. Protein synthesis regulation by anabolic and catabolic signaling was then examined. In the control condition, stretch increased mTORC1 activity and protein synthesis. The LLC treatment decreased basal mTORC1 activity and protein synthesis and attenuated the stretch induction of protein synthesis. LLC media increased STAT3 and AMP-activated protein kinase phosphorylation in myotubes, independent of stretch. Both stretch and LLC independently increased ERK1/2, p38, and NF-κB phosphorylation. In LLC-treated myotubes, the inhibition of ERK1/2 and p38 rescued the stretch induction of protein synthesis. Interestingly, either leukemia inhibitory factor or glycoprotein 130 antibody administration caused further inhibition of mTORC1 signaling and protein synthesis in stretched myotubes. AMP-activated protein kinase inhibition increased basal mTORC1 signaling activity and protein synthesis in LLC-treated myotubes, but did not restore the stretch induction of protein synthesis. These results demonstrate that LLC-derived cachectic factors can dissociate stretch-induced signaling from protein synthesis through ERK1/2 and p38 signaling, and that glycoprotein 130 signaling is associated with the basal stretch response in myotubes. Copyright © 2016 the American Physiological Society.

epsilon : A tool to find a canonical basis of master integrals

Science.gov (United States)

Prausa, Mario

2017-10-01

In 2013, Henn proposed a special basis for a certain class of master integrals, which are expressible in terms of iterated integrals. In this basis, the master integrals obey a differential equation, where the right hand side is proportional to ɛ in d = 4 - 2 ɛ space-time dimensions. An algorithmic approach to find such a basis was found by Lee. We present the tool epsilon, an efficient implementation of Lee's algorithm based on the Fermat computer algebra system as computational back end.

Effects of special composite stretching on the swing of amateur golf players.

Science.gov (United States)

Lee, Joong-Chul; Lee, Sung-Wan; Yeo, Yun-Ghi; Park, Gi Duck

2015-04-01

[Purpose] The study investigated stretching for safer a golf swing compared to present stretching methods for proper swings in order to examine the effects of stretching exercises on golf swings. [Subjects] The subjects were 20 amateur golf club members who were divided into two groups: an experimental group which performed stretching, and a control group which did not. The subjects had no bone deformity, muscle weakness, muscle soreness, or neurological problems. [Methods] A swing analyzer and a ROM measuring instrument were used as the measuring tools. The swing analyzer was a GS400-golf hit ball analyzer (Korea) and the ROM measuring instrument was a goniometer (Korea). [Results] The experimental group showed a statistically significant improvement in driving distance. After the special stretching training for golf, a statistically significant difference in hit-ball direction deviation after swings were found between the groups. The experimental group showed statistically significant decreases in hit ball direction deviation. After the special stretching training for golf, statistically significant differences in hit-ball speed were found between the groups. The experimental group showed significant increases in hit-ball speed. [Conclusion] To examine the effects of a special stretching program for golf on golf swing-related factors, 20 male amateur golf club members performed a 12-week stretching training program. After the golf stretching training, statistically significant differences were found between the groups in hit-ball driving distance, direction deviation, deflection distance, and speed.

Stretching and folding mechanism in foams

International Nuclear Information System (INIS)

Tufaile, Alberto; Pedrosa Biscaia Tufaile, Adriana

2008-01-01

We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board

Stretching and folding mechanism in foams

Energy Technology Data Exchange (ETDEWEB)

Tufaile, Alberto [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)], E-mail: tufaile@usp.br; Pedrosa Biscaia Tufaile, Adriana [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)

2008-10-13

We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board.

MESA models of the evolutionary state of the interacting binary epsilon Aurigae

Science.gov (United States)

Gibson, Justus L.; Stencel, Robert E.

2018-06-01

Using MESA code (Modules for Experiments in Stellar Astrophysics, version 9575), an evaluation was made of the evolutionary state of the epsilon Aurigae binary system (HD 31964, F0Iap + disc). We sought to satisfy several observational constraints: (1) requiring evolutionary tracks to pass close to the current temperature and luminosity of the primary star; (2) obtaining a period near the observed value of 27.1 years; (3) matching a mass function of 3.0; (4) concurrent Roche lobe overflow and mass transfer; (5) an isotopic ratio 12C/13C = 5 and, (6) matching the interferometrically determined angular diameter. A MESA model starting with binary masses of 9.85 + 4.5 M⊙, with a 100 d initial period, produces a 1.2 + 10.6 M⊙ result having a 547 d period, and a single digit 12C/13C ratio. These values were reached near an age of 20 Myr, when the donor star comes close to the observed luminosity and temperature for epsilon Aurigae A, as a post-RGB/pre-AGB star. Contemporaneously, the accretor then appears as an upper main-sequence, early B-type star. This benchmark model can provide a basis for further exploration of this interacting binary, and other long-period binary stars.

A Galilean and tensorial invariant k-epsilon model for near wall turbulence

Science.gov (United States)

Yang, Z.; Shih, T. H.

1993-01-01

A k-epsilon model is proposed for wall bounded turbulent flows. In this model, the eddy viscosity is characterized by a turbulent velocity scale and a turbulent time scale. The time scale is bounded from below by the Kolmogorov time scale. The dissipation rate equation is reformulated using this time scale and no singularity exists at the wall. A new parameter R = k/S(nu) is introduced to characterize the damping function in the eddy viscosity. This parameter is determined by local properties of both the mean and the turbulent flow fields and is free from any geometry parameter. The proposed model is then Galilean and tensorial invariant. The model constants used are the same as in the high Reynolds number Standard k-epsilon Model. Thus, the proposed model will also be suitable for flows far from the wall. Turbulent channel flows and turbulent boundary layer flows with and without pressure gradients are calculated. Comparisons with the data from direct numerical simulations and experiments show that the model predictions are excellent for turbulent channel flows and turbulent boundary layers with favorable pressure gradients, good for turbulent boundary layers with zero pressure gradients, and fair for turbulent boundary layer with adverse pressure gradients.

Raman spectroscopic study of the minerals apophyllite-(KF) KCa4Si8O20F·8H2O and apophyllite-(KOH) KCa4Si8O20(F,OH)·8H2O

Science.gov (United States)

Frost, Ray L.; Xi, Yunfei

2012-11-01

Raman spectroscopy complimented with infrared spectroscopy has been used to study the variation in molecular structure of two minerals of the apophyllite mineral group, namely apophyllite-(KF) KCa4Si8O20F·8H2O and apophyllite-(KOH) KCa4Si8O20(F,OH)·8H2O. apophyllite-(KF) and apophyllite-(KOH) are different minerals only because of the difference in the percentage of fluorine to hydroxyl ions. The Raman spectra are dominated by a very intense sharp peak at 1059 cm-1. A band at around 846 cm-1 is assigned to the water librational mode. It is proposed that the difference between apophyllite-(KF) and apophyllite-(KOH) is the observation of two Raman bands in the OH stretching region at around 3563 and 3625 cm-1. Multiple water stretching and bending modes are observed showing that there is much variation in hydrogen bonding between water and the silicate surfaces.

Fatigue Crack Growth Characteristics of Cold Stretched STS 304 Welded Joint

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong Won; Na, Seong Hyeon; Yoon, Dong Hyun; Kim, Jae Hoon [Chungnam Nat’l Univ., Daejeon (Korea, Republic of); Kim, Young Kyun; Kim, Ki Dong [Korea Gas Coporation R& D Division, Daejeon (Korea, Republic of)

2017-09-15

STS 304 steel is used as pressure vessel material, and although it exhibits excellent mechanical characteristics at a low temperature, it is heavier than other materials. To address this issue, a method using cold-stretching techniques for STS 304 can be applied. In this study, a cold-stretching part and welded joint specimen were directly obtained from a cold-stretching pressure vessel manufactured according to ASME code. Fatigue crack propagation tests were carried out at room temperature and -170℃ using the compliance method for stress ratios of 0.1 and 0.5. The results indicate that crack growth rate of the welded joint is higher than that of the cold-stretching part within the same stress intensity factor range. The outcome of this work is expected to serve as a basis for the development of a cold-stretched STS 304 pressure vessel.

Secondary digital nerve repair in the foot with resorbable p(DLLA-epsilon-CL) nerve conduits

NARCIS (Netherlands)

Meek, MF; Nicolai, JPA; Robinson, PH

Nerve guides are increasingly being used in peripheral nerve repair. In the last decade, Much preclinical research has been undertaken into a resorbable nerve guide composed of p(DLLA-epsilon-CL). This report describes the results of secondary digital nerve reconstruction in the foot in a patient

Chimeric immunoglobulin E reactive with tumor-associated antigen activates human Fc epsilon RI bearing cells

NARCIS (Netherlands)

Luiten, R. M.; Warnaar, S. O.; Schuurman, J.; Pasmans, S. G.; Latour, S.; Daëron, M.; Fleuren, G. J.; Litvinov, S. V.

1997-01-01

Crosslinking of immunoglobulin E molecules that are bound to the Fc epsilon receptors expressed on mast cells or basophils triggers activation of these cells, resulting in the development of a type I hypersensitivity. Targeting this potent immune reaction towards tumors by using IgE that reacts with

Using contour plots in elecgroproduction to examine regions in {epsilon}, Q{sup 2}, W space

Energy Technology Data Exchange (ETDEWEB)

Funsten, H. [College of William and Mary, Williamsburg, VA (United States)

1994-04-01

In determining incident CEBAF beam energies for CLAS electroproduction experiments that separate the longitudinal and transverse cross section components, contour plots of {epsilon} defined over a 2 dimensional Q{sup 2}, W space can be useful. This note describes an approximate method of constructing such plots.

Ellipsometric analysis of the oxidation of alpha-iron and epsilon-Fesub2Nsub1-x

DEFF Research Database (Denmark)

Graat, Peter C.J.; Somers, Marcel A. J.; Mittemeijer, Eric J.

1999-01-01

The initial oxidation of polycrystalline alpha-Fe and polycrystalline epsilon-Fe2N1-x was investigated with ellipsometry. Prior to oxidation the sample surfaces were subjected to a sputter cleaning pretreatment or a sputter cleaning plus annealing pretreatment. For the wavelength applied in the e...

The Properties of the local Interstellar Medium and the Interaction of the Stellar Winds of epsilon Indi and lambda Andromedae with the Interstellar Environment

Science.gov (United States)

Wood, Brian E.; Alexander, William R.; Linsky, Jeffrey L.

1996-01-01

We present new observations of the Ly alpha lines of Epsilon Indi (K5 5) and A Andromedae (G8 4-3 + ?) These data were obtained by the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope. Analysis of the interstellar H 1 and D 1 absorption lines reveals that the velocities and temperatures inferred from the H 1 lines are inconsistent with the parameters inferred from the D 1 lines, unless the H 1 absorption is assumed to be produced by two absorption components. One absorption component is produced by interstellar material. For both lines of sight observed, the velocity of this component is consistent with the velocity predicted by the local flow vector. For the Epsilon Indi data, the large velocity separation between the stellar emission and the interstellar absorption allows us to measure the H 1 column density independent of the shape of the intrinsic stellar Ly alpha profile. This approach permits us to quote an accurate column density and to assess its uncertainty with far more confidence than in previous analyses, for which the errors were dominated by uncertainties in the assumed stellar profiles.

Low cytotoxic tissue adhesive based on oxidized dextran and epsilon-poly-L-lysine.

Science.gov (United States)

Hyon, Suong-Hyu; Nakajima, Naoki; Sugai, Hajime; Matsumura, Kazuaki

2014-08-01

A novel adhesive hydrogel consisting of dextran and epsilon-poly(L-lysine) (dextran-PL) with multiple biomedical applications was developed. Periodate oxidation in aqueous media almost stoichiometrically introduces aldehyde groups in dextran molecules, and aldehyde dextran can react with the primary amino groups in epsilon-PL (ɛ-PL) at neutral pH to form a hydrogel. The gelation time of the hydrogel can be easily controlled by the extent of oxidation in dextran and of the acylation in ɛ-PL by anhydrides. The shear adhesion strength of dextran-PL was 10 times higher than that of fibrin glue, when wet collagen sheets were selected as test specimens. The cytotoxicity of aldehyde dextran and ɛ-PL were 1000 times lower than that of glutaraldehyde and poly(allylamine). The considerably low cytotoxicity of aldehyde dextran could be ascribed to its low reactivity with amine species when compared with glutaraldehyde. In contrast, a high reactivity of amino groups in ɛ-PL was observed when compared with glycine, L-lysine, and gelatin, which could be explained by their poor dissociation at neutral pH, thus leading to low cytotoxicity. © 2013 Wiley Periodicals, Inc.

The effectiveness of manual stretching in the treatment of plantar heel pain: a systematic review

Directory of Open Access Journals (Sweden)

Parish Ben

2011-06-01

Full Text Available Abstract Background Plantar heel pain is a commonly occurring foot complaint. Stretching is frequently utilised as a treatment, yet a systematic review focusing only on its effectiveness has not been published. This review aimed to assess the effectiveness of stretching on pain and function in people with plantar heel pain. Methods Medline, EMBASE, CINAHL, AMED, and The Cochrane Library were searched from inception to July 2010. Studies fulfilling the inclusion criteria were independently assessed, and their quality evaluated using the modified PEDro scale. Results Six studies including 365 symptomatic participants were included. Two compared stretching with a control, one study compared stretching to an alternative intervention, one study compared stretching to both alternative and control interventions, and two compared different stretching techniques and durations. Quality rating on the modified Pedro scale varied from two to eight out of a maximum of ten points. The methodologies and interventions varied significantly between studies, making meta-analysis inappropriate. Most participants improved over the course of the studies, but when stretching was compared to alternative or control interventions, the changes only reached statistical significance in one study that used a combination of calf muscle stretches and plantar fascia stretches in their stretching programme. Another study comparing different stretching techniques, showed a statistically significant reduction in some aspects of pain in favour of plantar fascia stretching over calf stretches in the short term. Conclusions There were too few studies to assess whether stretching is effective compared to control or other interventions, for either pain or function. However, there is some evidence that plantar fascia stretching may be more effective than Achilles tendon stretching alone in the short-term. Appropriately powered randomised controlled trials, utilizing validated outcome

Weak depth and along-strike variations in stretching from a multi-episodic finite stretching model: Evidence for uniform pure-shear extension in the opening of the South China Sea

Science.gov (United States)

Chen, Lin; Zhang, Zhongjie; Song, Haibin

2013-12-01

The South China Sea is widely believed to have been opened by seafloor spreading during the Cenozoic. The details of its lithospheric extension are still being debated, and it is unknown whether pure, simple, or conjunct shears are responsible for the opening of the South China Sea. The depth-dependent and along-strike extension derived from the single-stage finite stretching model or instantaneous stretching model is inconsistent with the observation that the South China Sea proto-margins have experienced multi-episodic extension since the Late Cretaceous. Based on the multi-episodic finite stretching model, we present the amount of lithosphere stretching at the northern continental margin of the South China Sea for different depth scales (upper crust, whole crust and lithosphere) and along several transects. The stretching factors are estimated by integrating seven deep-penetration seismic profiles, the Moho distribution derived from gravity modeling, and the tectonic subsidence data for 41 wells. The results demonstrate that the amount of stretching increases rapidly from 1.1 at the continent shelf to over 3.5 at the lower slope, but the stretching factors at the crust and lithosphere scales are consistent within error (from the uncertainty in paleobathymetry and sea-level change). Furthermore, the along-strike variation in stretching factor is within the range of 1.11-1.9 in west-east direction, accompanied by significant west-east differences in the thickness of high-velocity layers (HVLs) within the lowermost crust. This weak along-strike variation of the stretching factor is most likely produced by the preexisting contrasts in the composition and thermal structure of the lithosphere. The above observations suggest that the continental extension in the opening of the South China Sea mainly takes the form of a uniform pure shear rather than depth-dependent stretching.

The Use of Visual Approach in Teaching and Learning the Epsilon-Delta Definition of Continuity

Science.gov (United States)

Pešic, Duška; Pešic, Aleksandar

2015-01-01

In this paper we introduce a new collaborative technique in teaching and learning the epsilon-delta definition of a continuous function at the point from its domain, which connects mathematical logic, combinatorics and calculus. This collaborative approach provides an opportunity for mathematical high school students to engage in mathematical…

All-passive pixel super-resolution of time-stretch imaging

Science.gov (United States)

Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

2017-03-01

Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2-5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.

Stretching the Border

DEFF Research Database (Denmark)

Horstmann, Alexander

2014-01-01

In this paper, I hope to add a complementary perspective to James Scott’s recent work on avoidance strategies of subaltern mountain people by focusing on what I call the refugee public. The educated Karen elite uses the space of exile in the Thai borderland to reconstitute resources and to re-ent......-based organizations succeed to stretch the border by establishing a firm presence that is supported by the international humanitarian economy in the refugee camps in Northwestern Thailand....

Produção e caracterização de anticorpos monoclonais contra toxina épsilon de Clostridium perfringens Tipo D Production and characterization of monoclonal antibodies against Clostridium perfringens Type D epsilon toxin

Directory of Open Access Journals (Sweden)

Theonys Diógenes Freitas

2009-02-01

Full Text Available Clostridium perfringens tipo D é o agente etiológico da enterotoxemia em ruminantes, causada pela toxina épsilon e caracterizada por edema cardíaco, pulmonar, renal e cerebral. Anticorpos monoclonais contra toxina épsilon de C. perfringens tipo D foram produzidos a partir da fusão da linhagen de mieloma P3-X63-Ag8 653 com células do baço de camundongos Balb/c imunizados com o toxóide épsilon. Seis linhagens de híbridos secretores de anticorpos monoclonais das classes e IgM e IgG foram estabelecidas.Clostridium perfringens type D is the aetiological agent of enterotoxemia in ruminants. The disease is caused by epsilon toxin characterized by cardiac, pulmonary, kidney and brain edema. Monoclonal antibodies were produced by using myeloma cell line P3-X63-Ag8 653 fused with spleen cells from Balb/c mice, immunized with epsilon toxoid of C. perfringens type D. Six hybrids were established secreting monoclonal antibodies of the IgM class and IgG3 subclass.

Computation of nuclear reactor parameters using a stretch Kalman filtering

International Nuclear Information System (INIS)

Zwingelstein, G.; Poujol, A.

1976-01-01

A method of nonlinear stochastic filtering, the stretched Karman filter, is used for the estimation of two basic parameters involved in the control of nuclear reactor start-up. The corresponding algorithm is stored in a small Multi-8 computer and tested with data recorded for the Ulysse reactor (I.N.S.T.N.). The various practical problems involved in using the algorithm are examined: filtering initialization, influence of the model... The quality and time saving obtained in the computation make it possible for a real time operation, the computer being connected with the reactor [fr

A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

KAUST Repository

Chang, Y.-H.

2018-02-26

Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non-planar transverse stretching process was employed in this study to produce micro-porous structure. The morphology, membrane thickness, mean pore size, and porosity of the PTFE membrane were investigated. The results show that the non-planar transverse stretched membranes exhibit more uniform average pore diameter with thinner membrane thickness. Morphological changes induced by planar and non-planar transverse stretching for pore characteristics were investigated. The stretching conditions, stretching temperature and rate, affect the stretched membrane. Increasing temperature facilitated the uniformity of pore size and uniformity of membrane thickness. Moreover, increase in stretching rate resulted in finer pore size and thinner membrane.

Morphology in binary blends of poly(vinyl methyl ether) and epsilon-caprolactone-trimethylene carbonate diblock copolymer

NARCIS (Netherlands)

Luyten, MC; Bogels, EJF; vanEkenstein, GORA; tenBrinke, G; Bras, W; Komanschek, BE; Ryan, AJ

The morphology of symmetric diblock copolymer of epsilon-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray

Theory of high-force DNA stretching and overstretching.

Science.gov (United States)

Storm, C; Nelson, P C

2003-05-01

Single-molecule experiments on single- and double-stranded DNA have sparked a renewed interest in the force versus extension of polymers. The extensible freely jointed chain (FJC) model is frequently invoked to explain the observed behavior of single-stranded DNA, but this model does not satisfactorily describe recent high-force stretching data. We instead propose a model (the discrete persistent chain) that borrows features from both the FJC and the wormlike chain, and show that it resembles the data more closely. We find that most of the high-force behavior previously attributed to stretch elasticity is really a feature of the corrected entropic elasticity; the true stretch compliance of single-stranded DNA is several times smaller than that found by previous authors. Next we elaborate our model to allow coexistence of two conformational states of DNA, each with its own stretch and bend elastic constants. Our model is computationally simple and gives an excellent fit through the entire overstretching transition of nicked, double-stranded DNA. The fit gives the first value for the bend stiffness of the overstretched state. In particular, we find the effective bend stiffness for DNA in this state to be about 12 nm k(B)T, a value quite different from either the B-form or single-stranded DNA.

The Acute Effects of Upper Extremity Stretching on Throwing Velocity in Baseball Throwers

Directory of Open Access Journals (Sweden)

Michael Williams

2013-01-01

Full Text Available Purpose. To examine the effects of static and proprioceptive neuromuscular facilitation (PNF stretching of the shoulder internal rotators on throwing velocity. Subjects. 27 male throwers (mean age = 25.1 years old, SD = 2.4 with adequate knowledge of demonstrable throwing mechanics. Study Design. Randomized crossover trial with repeated measures. Methods. Subjects warmed up, threw 10 pitches at their maximum velocity, were randomly assigned to 1 of 3 stretching protocols (static, PNF, or no stretch, and then repeated their 10 pitches. Velocities were recorded after each pitch and average and peak velocities were recorded after each session. Results. Data were analyzed using a repeated measures ANOVA. No significant interaction between stretching and throwing velocity was observed. Main effects for time were not statistically significant. Main effects for the stretching groups were statistically significant. Discussion. Results suggest that stretching of the shoulder internal rotators did not significantly affect throwing velocity immediately after stretching. This may be due to the complexity of the throwing task. Conclusions. Stretching may be included in a thrower's warm-up without any effects on throwing velocity. Further research should be performed using a population with more throwing experience and skill.

Efficacy of hamstring stretching programs in schoolchildren. A systematic review

Directory of Open Access Journals (Sweden)

Carlos-Alberto BECERRA FERNANDEZ

2017-03-01

Full Text Available The main purpose of the present review was to examine the scientific literature on the effects of physical education-based stretching programs on hamstring extensibility in schoolchildren aged 6-11 years. For this purpose relevant studies were searched from ten electronic databases dated up through May 2015. Of the 25 potentially relevant articles identified and retrieved for more detailed evaluation, only eight studies were included in the present review because they met the inclusion criteria. The overall results showed that incorporating hamstring stretching as a part of physical education classes produces a significant improvement in the scores of the tests: straight leg raise and classic sit-and-reach, for the experimental groups, but not for control groups. Stretching programs can be included in Physical Education classes, specifically during the warm-up and the cool down periods in order to improve hamstring extensibility. Although it seems that the stretching exercises in the warm-up period could be less effective in gaining flexibility in school children. Studies that use a stretching volume between 4 and 7 minutes per session and 2-4 training classes per week, obtain statistically significant improvements on the levels of hamstring flexibility in the experimental groups. However, after a five-week detraining period, children revert back to their initial flexibility levels. Therefore, it seems appropriate that physical education teachers should implement stretching programs to improve the students´ flexibility during the Physical Education classes.

Implementation of a controller for linear positioners applicable in optical fiber stretching

International Nuclear Information System (INIS)

Castrillo Piedra, Andres Rodolfo

2014-01-01

A low cost controller is implemented for linear positioners applicable in optic fiber stretching. The possibility of using a donated equipment is evaluated by the Escuela de Ingenieria Mecanica. The equipment is required by the non-linear photonic research laboratory (NLPR-LAB) for stretching of micro structured fiber. The process has required a slow and precise stretching, so the controllers must be precisely programmed to rotate the motors at different speeds. Donated equipment is evaluated to see if it is possible to use for fiber stretching [es

Post-activation depression of soleus stretch reflexes in healthy and spastic humans

DEFF Research Database (Denmark)

Grey, Michael James; Klinge, Klaus; Crone, Clarissa

2007-01-01

Reduced depression of transmitter release from Ia afferents following previous activation (post-activation depression) has been suggested to be involved in the pathophysiology of spasticity. However, the effect of this mechanism on the myotatic reflex and its possible contribution to increased...... reflex excitability in spastic participants has not been tested. To investigate these effects, we examined post-activation depression in Soleus H-reflex responses and in mechanically evoked Soleus stretch reflex responses. Stretch reflex responses were evoked with consecutive dorsiflexion perturbations...... of the soleus stretch reflex and H-reflex decreased as the interval between the stimulus/perturbation was decreased. Similarly, the stretch-evoked torque decreased. In the spastic participants, the post-activation depression of both reflexes and the stretch-evoked torque was significantly smaller than...

Damage percolation during stretch flange forming of aluminum alloy sheet

Science.gov (United States)

Chen, Zengtao; Worswick, Michael J.; Keith Pilkey, A.; Lloyd, David J.

2005-12-01

A multi-scale finite element (FE)-damage percolation model was employed to simulate stretch flange forming of aluminum alloys AA5182 and AA5754. Material softening and strain gradients were captured using a Gurson-based FE model. FE results were then fed into the so-called damage percolation code, from which the damage development was modelled within measured microstructures. The formability of the stretch flange samples was predicted based upon the onset of catastrophic failure triggered by profuse void coalescence within the measured second-phase particle field. Damage development is quantified in terms of crack and void areal fractions, and compared to metallographic results obtained from interrupted stretch flange specimens. Parametric study is conducted on the effect of void nucleation strain in the prediction of formability of stretch flanges to "calibrate" proper nucleation strains for both alloys.

Effects of Functional Training and Calf Stretching on Risk of Falls in Older People: A Pilot Study.

Science.gov (United States)

do Rosario, Jailton Thulher; da Fonseca Martins, Natalia Santos; Peixinho, Carolina Carneiro; Oliveira, Liliam Fernandes

2017-04-01

This study aimed to determine the effects of a functional training and ankle stretching program in triceps surae torque, passive stiffness index, and in the risk for fall indicators in older adults. Twenty women (73.4 ± 7.3 years) were allocated into an intervention or control group. The 12-week intervention consisted of functional training and calf stretching exercises performed twice a week. Measurements of peak passive and active torque, passive stiffness, maximum dorsiflexion angle, and indexes of risk for falls (Timed Up and Go, functional reach test, QuickScreen-test) were collected. There were no significant differences for all variables, except the maximum dorsiflexion angle, which increased in the intervention group from 33.78 ± 8.57° to 38.89 ± 7.52°. The exercise program was not sufficient to enhance performance on functional tests and decrease the risk for falls in older adults. The significant increase in the maximum dorsiflexion indicates a positive impact of stretching exercises.

Coherent time-stretch transformation for real-time capture of wideband signals.

Science.gov (United States)

Buckley, Brandon W; Madni, Asad M; Jalali, Bahram

2013-09-09

Time stretch transformation of wideband waveforms boosts the performance of analog-to-digital converters and digital signal processors by slowing down analog electrical signals before digitization. The transform is based on dispersive Fourier transformation implemented in the optical domain. A coherent receiver would be ideal for capturing the time-stretched optical signal. Coherent receivers offer improved sensitivity, allow for digital cancellation of dispersion-induced impairments and optical nonlinearities, and enable decoding of phase-modulated optical data formats. Because time-stretch uses a chirped broadband (>1 THz) optical carrier, a new coherent detection technique is required. In this paper, we introduce and demonstrate coherent time stretch transformation; a technique that combines dispersive Fourier transform with optically broadband coherent detection.

Experimental Study of the Effects of EIPA, Losartan, and BQ-123 on Electrophysiological Changes Induced by Myocardial Stretch.

Science.gov (United States)

Chorro, Francisco J; Canto, Irene Del; Brines, Laia; Such-Miquel, Luis; Calvo, Conrado; Soler, Carlos; Zarzoso, Manuel; Trapero, Isabel; Tormos, Álvaro; Such, Luis

2015-12-01

Mechanical response to myocardial stretch has been explained by various mechanisms, which include Na(+)/H(+) exchanger activation by autocrine-paracrine system activity. Drug-induced changes were analyzed to investigate the role of these mechanisms in the electrophysiological responses to acute myocardial stretch. Multiple epicardial electrodes and mapping techniques were used to analyze changes in ventricular fibrillation induced by acute myocardial stretch in isolated perfused rabbit hearts. Four series were studied: control (n = 9); during perfusion with the angiotensin receptor blocker losartan (1 μM, n = 8); during perfusion with the endothelin A receptor blocker BQ-123 (0.1 μM, n = 9), and during perfusion with the Na(+)/H(+) exchanger inhibitor EIPA (5-[N-ethyl-N-isopropyl]-amiloride) (1 μM, n = 9). EIPA attenuated the increase in the dominant frequency of stretch-induced fibrillation (control=40.4%; losartan=36% [not significant]; BQ-123=46% [not significant]; and EIPA=22% [PII receptor antagonist losartan and the endothelin A receptor blocker BQ-123 did not modify these effects. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Ca{sup 2+} influx and ATP release mediated by mechanical stretch in human lung fibroblasts

Energy Technology Data Exchange (ETDEWEB)

Murata, Naohiko [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Ito, Satoru, E-mail: itori@med.nagoya-u.ac.jp [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Furuya, Kishio [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Takahara, Norihiro [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Naruse, Keiji [Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Okayama 700-8558 (Japan); Aso, Hiromichi; Kondo, Masashi [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Sokabe, Masahiro [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Hasegawa, Yoshinori [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan)

2014-10-10

Highlights: • Uniaxial stretching activates Ca{sup 2+} signaling in human lung fibroblasts. • Stretch-induced intracellular Ca{sup 2+} elevation is mainly via Ca{sup 2+} influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca{sup 2+} influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca{sup 2+}]{sub i} transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca{sup 2+}]{sub i}. The stretch-induced [Ca{sup 2+}]{sub i} elevation was attenuated in Ca{sup 2+}-free solution. In contrast, the increase of [Ca{sup 2+}]{sub i} by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd{sup 3+}, ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca{sup 2+}]{sub i} elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca{sup 2+} influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

Pulse shaping in the presence of enormous second-order dispersion in Al:ZnO/ZnO epsilon-near-zero metamaterial

Science.gov (United States)

Kelly, Priscilla; Kuznetsova, Lyuba

2018-04-01

A numerical study of the ultra-short pulse propagation in the aluminum-doped zinc oxide multi-layered metamaterial at the epsilon-near-zero spectral point is presented. The Drude model for dielectric permittivity and comparison with recent experimental data predict that damping frequency γD has the highest impact on the material losses and results in enormous second-order dispersion. Numerical simulations using both, the finite-difference time domain algorithm and the split-step Fourier method, show that variations of group velocity across the pulse at the epsilon-near-zero point results in a unique "soliton-like" propagation regime without nonlinearity for the propagation lengths of up to 300 nm.

Transient filament stretching rheometer II

DEFF Research Database (Denmark)

Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

1997-01-01

The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

Investing in a Large Stretch Press

Science.gov (United States)

Choate, M.; Nealson, W.; Jay, G.; Buss, W.

1986-01-01

Press for forming large aluminum parts from plates provides substantial economies. Study assessed advantages and disadvantages of investing in large stretch-forming press, and also developed procurement specification for press.

Fission cross section and fission fragment angular distribution for oriented nucleus fission by intermediate energy neutrons (epsilon < or approximately 1 Mev)

International Nuclear Information System (INIS)

Barabanov, A.L.; Grechukhin, D.P.

1985-01-01

General analysis is conducted, and formulae for fission cross section and angular distribution of fission fragments of oriented nuclei by fast neutrons are presented. Geometrical coefficients making up the formulae permitting to carry out calculations for target nuclei with spins I=3/2, 5/2, 7/2 at interaction energies epsilon < or approximately 1 MeV are tabulated. Results of demonstrative calculation of fission fragment angular distribution of oriented sup(235)U nuclei by 0.1 <= epsilon <= 1.0 MeV neutrons reveal that angular distribution weakly depends on the set of permeability factors of neutron waves applied in the calculations

Optimal stretching in the reacting wake of a bluff body.

Science.gov (United States)

Wang, Jinge; Tithof, Jeffrey; Nevins, Thomas D; Colón, Rony O; Kelley, Douglas H

2017-12-01

We experimentally study spreading of the Belousov-Zhabotinsky reaction behind a bluff body in a laminar flow. Locations of reacted regions (i.e., regions with high product concentration) correlate with a moderate range of Lagrangian stretching and that range is close to the range of optimal stretching previously observed in topologically different flows [T. D. Nevins and D. H. Kelley, Phys. Rev. Lett. 117, 164502 (2016)]. The previous work found optimal stretching in a closed, vortex dominated flow, but this article uses an open flow and only a small area of appreciable vorticity. We hypothesize that optimal stretching is common in advection-reaction-diffusion systems with an excitation threshold, including excitable and bistable systems, and that the optimal range depends on reaction chemistry and not on flow shape or characteristic speed. Our results may also give insight into plankton blooms behind islands in ocean currents.

Stretching of material lines in pseudo-turbulence induced by small rising bubbles

International Nuclear Information System (INIS)

Tanaka, M; Tsujimura, Y; Kanatani, H

2011-01-01

Direct numerical simulations have been conducted for the stretching of material lines in pseudo-turbulence induced by small rising bubbles in order to understand the mixing characteristics of bubbly flows. Contaminated bubbles are considered and are treated as light solid particles. An immersed boundary method has been used for evaluating the coupling force between the bubbles and the surrounding fluid flows. Numerical results show that the total length of material lines increases exponentially in time as a result of stretching and folding due to the rising bubbles. The material lines tend to accumulate in the wake regions of the bubbles, and they are strongly stretched in the vertical direction there. It is also found that the stretching rate of material lines increases with the mean void fraction when it is normalized by the magnitude of the rate-of-strain tensor of liquid flow in pseudo-turbulence. In the case of high void fractions, material lines tend to align with the direction of maximum stretching, and are effectively stretched.

Stretching of material lines in pseudo-turbulence induced by small rising bubbles

Energy Technology Data Exchange (ETDEWEB)

Tanaka, M; Tsujimura, Y; Kanatani, H, E-mail: mtanaka@kit.ac.jp [Department of Mechanical and System Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)

2011-12-22

Direct numerical simulations have been conducted for the stretching of material lines in pseudo-turbulence induced by small rising bubbles in order to understand the mixing characteristics of bubbly flows. Contaminated bubbles are considered and are treated as light solid particles. An immersed boundary method has been used for evaluating the coupling force between the bubbles and the surrounding fluid flows. Numerical results show that the total length of material lines increases exponentially in time as a result of stretching and folding due to the rising bubbles. The material lines tend to accumulate in the wake regions of the bubbles, and they are strongly stretched in the vertical direction there. It is also found that the stretching rate of material lines increases with the mean void fraction when it is normalized by the magnitude of the rate-of-strain tensor of liquid flow in pseudo-turbulence. In the case of high void fractions, material lines tend to align with the direction of maximum stretching, and are effectively stretched.

Expression of cytoplasmic CD3 epsilon proteins in activated human adult natural killer (NK) cells and CD3 gamma, delta, epsilon complexes in fetal NK cells. Implications for the relationship of NK and T lymphocytes

NARCIS (Netherlands)

Lanier, L. L.; Chang, C.; Spits, H.; Phillips, J. H.

1992-01-01

NK cells have been defined as CD3-, CD16+, and/or CD56+ lymphocytes that mediate MHC-unrestricted cytotoxicity against certain tumors and virus-infected cells. Although CD3 epsilon transcripts have been detected in some NK clones, it has generally been thought that NK cells do not express CD3

Complex epsilon-near-zero metamaterials for broadband light harvesting systems

KAUST Repository

Bonifazi, Marcella; Tian, Yi; Fratalocchi, Andrea

2018-01-01

We engineered an epsilon-near-zero (ENZ) material from suitably disordered metallic nanostructures. We create a new class of dispersionless composite materials that efficiently harnesses white light. By means of Atomic Force Microscopy (AFM) and Photoluminescence (PLE) measurements we experimentally demonstrate that this nanomaterial increases up to a record value the absorption of ultra-thin light harvesting films at visible and infrared wavelengths. Moreover, we obtained a 170% broadband increase of the external quantum efficiency (EQE) when these ENZ materials are inserted in an energy-harvesting module. We developed an inexpensive electrochemical deposition process that enables large-scale production of this material for energy-harvesting applications.

Complex epsilon-near-zero metamaterials for broadband light harvesting systems

KAUST Repository

Bonifazi, Marcella

2018-02-17

We engineered an epsilon-near-zero (ENZ) material from suitably disordered metallic nanostructures. We create a new class of dispersionless composite materials that efficiently harnesses white light. By means of Atomic Force Microscopy (AFM) and Photoluminescence (PLE) measurements we experimentally demonstrate that this nanomaterial increases up to a record value the absorption of ultra-thin light harvesting films at visible and infrared wavelengths. Moreover, we obtained a 170% broadband increase of the external quantum efficiency (EQE) when these ENZ materials are inserted in an energy-harvesting module. We developed an inexpensive electrochemical deposition process that enables large-scale production of this material for energy-harvesting applications.

Time stretch and its applications

Science.gov (United States)

Mahjoubfar, Ata; Churkin, Dmitry V.; Barland, Stéphane; Broderick, Neil; Turitsyn, Sergei K.; Jalali, Bahram

2017-06-01

Observing non-repetitive and statistically rare signals that occur on short timescales requires fast real-time measurements that exceed the speed, precision and record length of conventional digitizers. Photonic time stretch is a data acquisition method that overcomes the speed limitations of electronic digitizers and enables continuous ultrafast single-shot spectroscopy, imaging, reflectometry, terahertz and other measurements at refresh rates reaching billions of frames per second with non-stop recording spanning trillions of consecutive frames. The technology has opened a new frontier in measurement science unveiling transient phenomena in nonlinear dynamics such as optical rogue waves and soliton molecules, and in relativistic electron bunching. It has also created a new class of instruments that have been integrated with artificial intelligence for sensing and biomedical diagnostics. We review the fundamental principles and applications of this emerging field for continuous phase and amplitude characterization at extremely high repetition rates via time-stretch spectral interferometry.

Contact of a spherical probe with a stretched rubber substrate

Science.gov (United States)

Frétigny, Christian; Chateauminois, Antoine

2017-07-01

We report on a theoretical and experimental investigation of the normal contact of stretched neo-Hookean substrates with rigid spherical probes. Starting from a published formulation of surface Green's function for incremental displacements on a prestretched, neo-Hookean, substrate [J. Mech. Phys. Solids 56, 2957 (2008), 10.1016/j.jmps.2008.07.002], a model is derived for both adhesive and nonadhesive contacts. The shape of the elliptical contact area together with the contact load and the contact stiffness are predicted as a function of the in-plane stretch ratios λx and λy of the substrate. The validity of this model is assessed by contact experiments carried out using an uniaxally stretched silicone rubber. For stretch ratio below about 1.25, a good agreement is observed between theory and experiments. Above this threshold, some deviations from the theoretical predictions are induced as a result of the departure of the mechanical response of the silicone rubber from the neo-Hokeean description embedded in the model.

Periostin inhibits mechanical stretch-induced apoptosis in osteoblast-like MG-63 cells.

Science.gov (United States)

Yu, Kai-Wen; Yao, Chung-Chen; Jeng, Jiiang-Huei; Shieh, Hao-Ying; Chen, Yi-Jane

2018-04-01

Appropriate mechanical stress plays an important role in regulating the proliferation and differentiation of osteoblasts, whereas high-level mechanical stress may be harmful and compromise cell survival. Periostin, a matricellular protein, is essential in maintaining functional integrity of bone and collagen-rich connective tissue in response to mechanical stress. This study investigated whether or not high-level mechanical stretch induces cell apoptosis and the regulatory role of periostin in mechanical stretch-induced apoptosis in osteoblastic cells. Osteoblast-like MG-63 cells were seeded onto Bio-Flex I culture plates and subjected to cyclic mechanical stretching (15% elongation, 0.1 Hz) in a Flexercell tension plus system-5000. The same process was applied to cells pre-treated with exogenous human recombinant periostin before mechanical stretching. We used a chromatin condensation and membrane permeability dead cell apoptosis kit to evaluate the stretch-induced cell responses. Expression of caspase-3 and cPARP was examined by immunofluorescent stain and flow cytometry. The expression of periostin in MG-63 cells is involved in the TGF-β signaling pathway. High-level cyclic mechanical stretch induced apoptotic responses in MG-63 osteoblastic cells. The percentages of apoptotic cells and cells expressing cPARP protein increased in the groups of cells subjected to mechanical stretch, but these responses were absent in the presence of exogenous periostin. Our study revealed that high-level mechanical stretch induces apoptotic cell death, and that periostin plays a protective role against mechanical stretch-induced apoptosis in osteoblastic cells. Copyright © 2017. Published by Elsevier B.V.

Measurement of Resistive Plantar Flexion Torque of the Ankle during Passive Stretch in Healthy Subjects and Patients with Poststroke Hemiplegia.

Science.gov (United States)

Mizuno, Shiho; Sonoda, Shigeru; Takeda, Kotaro; Maeshima, Shinichiro

2016-04-01

Quantification of increased muscle tone for patients with spasticity has been performed to date using various devices to replace the manual scales, such as the modified Ashworth scale or the Tardieu scale. We developed a device that could measure resistive plantar flexion (PF) torque of the ankle during passive dorsiflexion (DF) as an indicator of muscle tone of ankle plantar flexors. The primary objective was to explore the test-retest intrarater reliability of a custom-built device. Participants were 11 healthy subjects (7 men, 4 women; mean age 47.0 years) and 22 patients with poststroke hemiplegia (11 hemorrhagic, 11 ischemic; 14 men, 8 women; mean age 57.2 years). The device was affixed to the ankle. Subjects were seated with knees either flexed or extended. The ankle was passively dorsiflexed from 20° of PF to more than 10° of DF at 5°/second (slow stretch) or 90°/second (fast stretch). Angle and torque were measured twice during the stretches. The intraclass correlation coefficients (ICCs) of torque at 10° of DF (T10) in the 4 conditions-slow and fast stretches with knee flexed or extended-were calculated. The T10 ICCs of the 4 conditions were .95-.99 in both groups. The healthy subjects showed significantly higher T10 of knee extension than of knee flexion during slow and fast stretches. The patients showed increased velocity-dependent torque during fast stretches. Excellent reliability was observed. The device is suitable for measuring resistive PF torque during passive stretch in a flexed knee condition. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Force encoding in muscle spindles during stretch of passive muscle.

Directory of Open Access Journals (Sweden)

Kyle P Blum

2017-09-01

Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

Force encoding in muscle spindles during stretch of passive muscle.

Science.gov (United States)

Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

2017-09-01

Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

Stretch activates human myometrium via ERK, caldesmon and focal adhesion signaling.

Directory of Open Access Journals (Sweden)

Yunping Li

2009-10-01

Full Text Available An incomplete understanding of the molecular mechanisms responsible for myometrial activation from the quiescent pregnant state to the active contractile state during labor has hindered the development of effective therapies for preterm labor. Myometrial stretch has been implicated clinically in the initiation of labor and the etiology of preterm labor, but the molecular mechanisms involved in the human have not been determined. We investigated the mechanisms by which gestation-dependent stretch contributes to myometrial activation, by using human uterine samples from gynecologic hysterectomies and Cesarean sections. Here we demonstrate that the Ca requirement for activation of the contractile filaments in human myometrium increases with caldesmon protein content during gestation and that an increase in caldesmon phosphorylation can reverse this inhibitory effect during labor. By using phosphotyrosine screening and mass spectrometry of stretched human myometrial samples, we identify 3 stretch-activated focal adhesion proteins, FAK, p130Cas, and alpha actinin. FAK-Y397, which signals integrin engagement, is constitutively phosphorylated in term human myometrium whereas FAK-Y925, which signals downstream ERK activation, is phosphorylated during stretch. We have recently identified smooth muscle Archvillin (SmAV as an ERK regulator. A newly produced SmAV-specific antibody demonstrates gestation-specific increases in SmAV protein levels and stretch-specific increases in SmAV association with focal adhesion proteins. Thus, whereas increases in caldesmon levels suppress human myometrium contractility during pregnancy, stretch-dependent focal adhesion signaling, facilitated by the ERK activator SmAV, can contribute to myometrial activation. These results suggest that focal adhesion proteins may present new targets for drug discovery programs aimed at regulation of uterine contractility.

Soleus stretch reflex during cycling

DEFF Research Database (Denmark)

Grey, Michael James; Pierce, C. W.; Milner, T. E.

2001-01-01

The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

Optical tweezers stretching of chromatin

NARCIS (Netherlands)

Pope, L.H.; Bennink, Martin L.; Greve, Jan

2003-01-01

Recently significant success has emerged from exciting research involving chromatin stretching using optical tweezers. These experiments, in which a single chromatin fibre is attached by one end to a micron-sized bead held in an optical trap and to a solid surface or second bead via the other end,

Acute effects of 15min static or contract-relax stretching modalities on plantar flexors neuromuscular properties.

Science.gov (United States)

Babault, Nicolas; Kouassi, Blah Y L; Desbrosses, Kevin

2010-03-01

The present study aimed to investigate the immediate effects of 15 min static or sub-maximal contract-relax stretching modalities on the neuromuscular properties of plantar flexor muscles. Ten male volunteers were tested before and immediately after 15 min static or contract-relax stretching programs of plantar flexor muscles (20 stretches). Static stretching consisted in 30s stretches to the point of discomfort. For the contract-relax stretching modality, subjects performed 6s sub-maximal isometric plantar flexion before 24s static stretches. Measurements included maximal voluntary isometric torque (MVT) and the corresponding electromyographic activity of soleus (SOL) and medial gastrocnemius (MG) muscles (RMS values), as well as maximal peak torque (Pt) elicited at rest by single supramaximal electrical stimulation of the tibial nerve. After 15 min stretching, significant MVT and SOL RMS decreases were obtained (-6.9+/-11.6% and -6.5+/-15.4%, respectively). No difference was obtained between stretching modalities. Pt remained unchanged after stretching. MG RMS changes were significantly different between stretching modalities (-9.4+/-18.3% and +3.5+/-11.6% after static and contract-relax stretching modalities, respectively). These findings indicated that performing 15 min static or contract-relax stretching had detrimental effects on the torque production capacity of plantar flexor muscles and should be precluded before competition. Mechanisms explaining this alteration seemed to be stretch modality dependent. Copyright 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Over-production, renaturation and reconstitution of delta and epsilon subunits from chloroplast and cyanobacterial F1

NARCIS (Netherlands)

Steinemann, D.; Lill, H; Junge, Wolfgang; Engelbrecht, Siegfried

1994-01-01

We studied the functioning of chimeric F0F1-ATPases by replacing subunits delta and epsilon of spinach CF1 with their counterparts from Synechocystis sp. PCC 6803. The sequence identities between these subunits are 26 and 41%, respectively. For a systematic approach to such studies and later

Stretching Diagnostics and Mixing Properties In The Stratosphere

Science.gov (United States)

Legras, B.; Shuckburgh, E.

The "finite size Lyapunov exponent" and the "effective diffusivity" are two diagnos- tics of mixing which have been recently introduced to investigate atmospheric flows. Both have been used to successfully identify the barriers to transport, for instance at the edge of the stratospheric polar vortex. Here we compare the two diagnostics in detail. The equivalent length has the advantage of arising as a mixing quantification from a rigid theoretical framework, however it has the disadvantage of being an aver- age quantity (the average around a tracer contour). The finite size Lyapunov exponent may be defined at any point in the flow, and quantifies the stretching properties expe- rienced by a fluid parcel both in its past and future evolution. In particular, the lines of maximum stretching at any time delineate the building blocks of the chaotic stirring. However the interpretation of the finite size Lyapunov exponent as a mixing time is less direct and depends on the alignment of tracer contours with the stretching lines.

History-dependence of muscle slack length following contraction and stretch in the human vastus lateralis.

Science.gov (United States)

Stubbs, Peter W; Walsh, Lee D; D'Souza, Arkiev; Héroux, Martin E; Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

2018-06-01

In reduced muscle preparations, the slack length and passive stiffness of muscle fibres have been shown to be influenced by previous muscle contraction or stretch. In human muscles, such behaviours have been inferred from measures of muscle force, joint stiffness and reflex magnitudes and latencies. Using ultrasound imaging, we directly observed that isometric contraction of the vastus lateralis muscle at short lengths reduces the slack lengths of the muscle-tendon unit and muscle fascicles. The effect is apparent 60 s after the contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles. In reduced muscle preparations, stretch and muscle contraction change the properties of relaxed muscle fibres. In humans, effects of stretch and contraction on properties of relaxed muscles have been inferred from measurements of time taken to develop force, joint stiffness and reflex latencies. The current study used ultrasound imaging to directly observe the effects of stretch and contraction on muscle-tendon slack length and fascicle slack length of the human vastus lateralis muscle in vivo. The muscle was conditioned by (a) strong isometric contractions at long muscle-tendon lengths, (b) strong isometric contractions at short muscle-tendon lengths, (c) weak isometric contractions at long muscle-tendon lengths and (d) slow stretches. One minute after conditioning, ultrasound images were acquired from the relaxed muscle as it was slowly lengthened through its physiological range. The ultrasound image sequences were used to identify muscle-tendon slack angles and fascicle slack lengths. Contraction at short muscle-tendon lengths caused a mean 13.5 degree (95% CI 11.8-15.0 degree) shift in the muscle-tendon slack angle towards shorter muscle-tendon lengths, and a mean 5 mm (95% CI 2-8 mm) reduction in fascicle slack length, compared to the

Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1.

Science.gov (United States)

Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

2015-02-01

Rac1 regulates stretch-stimulated (i.e. mechanical stress) glucose transport in muscle. Actin depolymerization decreases stretch-induced glucose transport in skeletal muscle. Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30-50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40-50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30-40% in tension developing muscle but did not affect contraction-stimulated glucose transport in

Possible stretched exponential parametrization for humidity absorption in polymers.

Science.gov (United States)

Hacinliyan, A; Skarlatos, Y; Sahin, G; Atak, K; Aybar, O O

2009-04-01

Polymer thin films have irregular transient current characteristics under constant voltage. In hydrophilic and hydrophobic polymers, the irregularity is also known to depend on the humidity absorbed by the polymer sample. Different stretched exponential models are studied and it is shown that the absorption of humidity as a function of time can be adequately modelled by a class of these stretched exponential absorption models.

Process Parameter Identification in Thin Film Flows Driven by a Stretching Surface

Directory of Open Access Journals (Sweden)

Satyananda Panda

2014-01-01

Full Text Available The flow of a thin liquid film over a heated stretching surface is considered in this study. Due to a potential nonuniform temperature distribution on the stretching sheet, a temperature gradient occurs in the fluid which produces surface tension gradient at the free surface of the thin film. As a result, the free surface deforms and these deformations are advected by the flow in the stretching direction. This work focuses on the inverse problem of reconstructing the sheet temperature distribution and the sheet stretch rate from observed free surface variations. This work builds on the analysis of Santra and Dandapat (2009 who, based on the long-wave expansion of the Navier-Stokes equations, formulate a partial differential equation which describes the evolution of the thickness of a film over a nonisothermal stretched surface. In this work, we show that after algebraic manipulation of a discrete form of the governing equations, it is possible to reconstruct either the unknown temperature field on the sheet and hence the resulting heat transfer or the stretching rate of the underlying surface. We illustrate the proposed methodology and test its applicability on a range of test problems.

Fuchsia : A tool for reducing differential equations for Feynman master integrals to epsilon form

Science.gov (United States)

Gituliar, Oleksandr; Magerya, Vitaly

2017-10-01

We present Fuchsia - an implementation of the Lee algorithm, which for a given system of ordinary differential equations with rational coefficients ∂x J(x , ɛ) = A(x , ɛ) J(x , ɛ) finds a basis transformation T(x , ɛ) , i.e., J(x , ɛ) = T(x , ɛ) J‧(x , ɛ) , such that the system turns into the epsilon form : ∂xJ‧(x , ɛ) = ɛ S(x) J‧(x , ɛ) , where S(x) is a Fuchsian matrix. A system of this form can be trivially solved in terms of polylogarithms as a Laurent series in the dimensional regulator ɛ. That makes the construction of the transformation T(x , ɛ) crucial for obtaining solutions of the initial system. In principle, Fuchsia can deal with any regular systems, however its primary task is to reduce differential equations for Feynman master integrals. It ensures that solutions contain only regular singularities due to the properties of Feynman integrals. Program Files doi:http://dx.doi.org/10.17632/zj6zn9vfkh.1 Licensing provisions: MIT Programming language:Python 2.7 Nature of problem: Feynman master integrals may be calculated from solutions of a linear system of differential equations with rational coefficients. Such a system can be easily solved as an ɛ-series when its epsilon form is known. Hence, a tool which is able to find the epsilon form transformations can be used to evaluate Feynman master integrals. Solution method: The solution method is based on the Lee algorithm (Lee, 2015) which consists of three main steps: fuchsification, normalization, and factorization. During the fuchsification step a given system of differential equations is transformed into the Fuchsian form with the help of the Moser method (Moser, 1959). Next, during the normalization step the system is transformed to the form where eigenvalues of all residues are proportional to the dimensional regulator ɛ. Finally, the system is factorized to the epsilon form by finding an unknown transformation which satisfies a system of linear equations. Additional comments

INFERENCES ON THE DISTRIBUTION OF Ly{alpha} EMISSION OF z {approx} 7 AND z {approx} 8 GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Treu, Tommaso; Auger, Matthew W. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Trenti, Michele [University of Colorado, Center for Astrophysics and Space Astronomy, 389-UCB, Boulder, CO 80309 (United States); Stiavelli, Massimo; Bradley, Larry D., E-mail: tt@physics.ucsb.edu [Space Telescope Science Institute, 3700 San Martin Dr, Baltimore MD 21218 (United States)

2012-03-01

Spectroscopic confirmation of galaxies at z {approx} 7 and above has been extremely difficult, owing to a drop in intensity of Ly{alpha} emission in comparison with samples at z {approx} 6. This crucial finding could potentially signal the ending of cosmic reionization. However, it is based on small data sets, often incomplete and heterogeneous in nature. We introduce a flexible Bayesian framework, useful to interpret such evidence. Within this framework, we implement two simple phenomenological models: a smooth one where the distribution of Ly{alpha} is attenuated by a factor {epsilon}{sub s} with respect to z {approx} 6 and a patchy one where a fraction {epsilon}{sub p} is absorbed/non-emitted while the rest is unabsorbed. From a compilation of 39 observed z {approx} 7 galaxies, we find {epsilon}{sub s} = 0.69 {+-} 0.12 and {epsilon}{sub p} = 0.66 {+-} 0.16. The models can be used to compute fractions of emitters above any equivalent width W. For W > 25 A, we find X{sup 25}{sub z=7} = 0.37 {+-} 0.11 (0.14 {+-} 0.06) for galaxies fainter (brighter) than M{sub UV} = -20.25 for the patchy model, consistent with previous work, but with smaller uncertainties by virtue of our full use of the data. At z {approx} 8 we combine new deep (5{sigma} flux limit 10{sup -17} erg s{sup -1} cm{sup -2}) Keck/NIRSPEC observations of a bright Y-dropout identified by our Brightest of Reionization Galaxies Survey, with those of three objects from the literature and find that the inference is inconclusive. We compute predictions for future near-infrared spectroscopic surveys and show that it is challenging but feasible to constrain the distribution of Ly{alpha} emitters at z {approx} 8 and distinguish between models.

Dynamics and structure of stretched flames

Energy Technology Data Exchange (ETDEWEB)

Law, C.K. [Princeton Univ., NJ (United States)

1993-12-01

This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

Excluded Volume Effects in Gene Stretching

OpenAIRE

Lam, Pui-Man

2002-01-01

We investigate the effects excluded volume on the stretching of a single DNA in solution. We find that for small force F, the extension h is not linear in F but proportion to F^{\\chi}, with \\chi=(1-\

Stretched versus compressed exponential kinetics in α-helix folding

International Nuclear Information System (INIS)

Hamm, Peter; Helbing, Jan; Bredenbeck, Jens

2006-01-01

In a recent paper (J. Bredenbeck, J. Helbing, J.R. Kumita, G.A. Woolley, P. Hamm, α-helix formation in a photoswitchable peptide tracked from picoseconds to microseconds by time resolved IR spectroscopy, Proc. Natl. Acad. Sci USA 102 (2005) 2379), we have investigated the folding of a photo-switchable α-helix with a kinetics that could be fit by a stretched exponential function exp(-(t/τ) β ). The stretching factor β became smaller as the temperature was lowered, a result which has been interpreted in terms of activated diffusion on a rugged energy surface. In the present paper, we discuss under which conditions diffusion problems occur with stretched exponential kinetics (β 1). We show that diffusion problems do have a strong tendency to yield stretched exponential kinetics, yet, that there are conditions (strong perturbation from equilibrium, performing the experiment in the folding direction) under which compressed exponential kinetics would be expected instead. We discuss the kinetics on free energy surfaces predicted by simple initiation-propagation models (zipper models) of α-helix folding, as well as by folding funnel models. We show that our recent experiment has been performed under condition for which models with strong downhill driving force, such as the zipper model, would predict compressed, rather than stretched exponential kinetics, in disagreement with the experimental observation. We therefore propose that the free energy surface along a reaction coordinate that governs the folding kinetics must be relatively flat and has a shape similar to a 1D golf course. We discuss how this conclusion can be unified with the thermodynamically well established zipper model by introducing an additional kinetic reaction coordinate

Effect of Twisting and Stretching on Magneto Resistance and Spin Filtration in CNTs

Directory of Open Access Journals (Sweden)

Anil Kumar Singh

2017-08-01

Full Text Available Spin-dependent quantum transport properties in twisted carbon nanotube and stretched carbon nanotube are calculated using density functional theory (DFT and non-equilibrium green’s function (NEGF formulation. Twisting and stretching have no effect on spin transport in CNTs at low bias voltages. However, at high bias voltages the effects are significant. Stretching restricts any spin-up current in antiparallel configuration (APC, which results in higher magneto resistance (MR. Twisting allows spin-up current almost equivalent to the pristine CNT case, resulting in lower MR. High spin filtration is observed in PC and APC for pristine, stretched and twisted structures at all applied voltages. In APC, at low voltages spin filtration in stretched CNT is higher than in pristine and twisted ones, with pristine giving a higher spin filtration than twisted CNT.

Effect of Ankle Positioning During Hamstring Stretches for Improving Straight Leg Hip Flexion Motion.

Science.gov (United States)

Laudner, Kevin G; Benjamin, Peter J; Selkow, Noelle M

2016-03-01

To compare the effects of stretching the hamstrings with the ankle in either a plantar-flexed (PF) or dorsiflexed (DF) position for improving straight leg hip flexion range of motion (ROM) over a 4-week period. Randomized, single-blinded, pretest, posttest design. Athletic training facility. Each limb of 34 asymptomatic individuals (15 males, 19 females) was randomly assigned to one of the 3 groups. Twenty-four limbs received hamstring stretches with the ankle in DF, 24 limbs received hamstring stretches with the ankle in PF, and 20 limbs received no stretch (control). Ankle position (PF, DF) during hamstring stretching. We measured pretest and posttest passive straight leg hip flexion ROM with the test ankle in a neutral position. For the intervention groups, the test limb was passively stretched with the ankle held in end range DF or PF for their respective group. Each stretch was held for 30 seconds for a total of 3 applications. Two treatment sessions were completed per week for a total of 4 weeks. The control limbs received no stretching during the 4-week period. We conducted 1-way analyses of covariance to determine significant changes in ROM between groups (P hamstrings in either PF or DF improve straight leg hip ROM compared with a control group. The results of this study should be considered by clinicians when determining the optimal stretching techniques aimed at increasing hamstring length.

Flow of viscous fluid along an exponentially stretching curved surface

Directory of Open Access Journals (Sweden)

N.F. Okechi

Full Text Available In this paper, we present the boundary layer analysis of flow induced by rapidly stretching curved surface with exponential velocity. The governing boundary value problem is reduced into self-similar form using a new similarity transformation. The resulting equations are solved numerically using shooting and Runge-Kutta methods. The numerical results depicts that the fluid velocity as well as the skin friction coefficient increases with the surface curvature, similar trend is also observed for the pressure. The dimensionless wall shear stress defined for this problem is greater than that of a linearly stretching curved surface, but becomes comparably less for a surface stretching with a power-law velocity. In addition, the result for the plane surface is a special case of this study when the radius of curvature of the surface is sufficiently large. The numerical investigations presented in terms of the graphs are interpreted with the help of underlying physics of the fluid flow and the consequences arising from the curved geometry. Keywords: Boundary layer flow, Curved surface, Exponential stretching, Curvature

Directional Cell Migration in Response to Repeated Substratum Stretching

Science.gov (United States)

Okimura, Chika; Iwadate, Yoshiaki

2017-10-01

Crawling migration plays an essential role in a variety of biological phenomena, including development, wound healing, and immune system function. Migration properties such as anterior-posterior polarity, directionality, and velocity are regulated not only by the reception of a chemoattractant but also by sensing mechanical inputs from the external environment. In this review, we describe the mechanical response of migrating cells, particularly under repeated stretching of the elastic substratum, highlighting the fact that there appear to be two independent mechanosensing systems that generate the polarity needed for migration. Cells that have no stress fibers, such as Dictyostelium cells and neutrophil-like differentiated HL-60 cells, migrate perpendicular to the stretching direction via myosin II localization. Cells that do possess stress fibers, however, such as fish keratocytes, migrate parallel to the stretching via a stress-fiber-dependent process.

Cryogenic grinding of electrospun poly-epsilon-caprolactone mesh submerged in liquid media

Czech Academy of Sciences Publication Activity Database

Knotek, P.; Pouzar, M.; Buzgo, Matej; Křížková, B.; Vlček, Milan; Míčková, Andrea; Plencner, Martin; Návesník, J.; Amler, Evžen; Bělina, P.

2012-01-01

Roč. 32, č. 6 (2012), s. 1366-1374 ISSN 0928-4931 Grant - others:GA MŠk(CZ) GA UK 330611; GA MŠk(CZ) GA UK 384311; GA MŠk(CZ) GA UK 99610; GA MŠk(CZ) ME 10145; GA MŠk(CZ) MSM0021627501; GA MŠk(CZ) ERA-NET Carsila ME10145; EU FP7(XE) BIOSCENT ID 214539 Institutional research plan: CEZ:AV0Z50390703; CEZ:AV0Z40500505 Keywords : cryogenic grinding * poly-epsilon-caprolactone * nano/micro-mesh Subject RIV: BO - Biophysics Impact factor: 2.404, year: 2012

On prediction of OH stretching frequencies in intramolecularly hydrogen bonded systems

DEFF Research Database (Denmark)

Hansen, Poul Erik; Spanget-Larsen, Jens

2012-01-01

OH stretching frequencies are investigated for a series of non-tautomerizing systems with intramolecular hydrogen bonds. Effective OH stretching wavenumbers are predicted by the application of empirical correlation procedures based on the results of B3LYP/6-31G(d) theoretical calculations...

Optimization of path length stretching in Monte Carlo calculations for non-leakage problems

Energy Technology Data Exchange (ETDEWEB)

Hoogenboom, J.E. [Delft Univ. of Technology (Netherlands)

2005-07-01

Path length stretching (or exponential biasing) is a well known variance reduction technique in Monte Carlo calculations. It can especially be useful in shielding problems where particles have to penetrate a lot of material before being tallied. Several authors sought for optimization of the path length stretching parameter for detection of the leakage of neutrons from a slab. Here the adjoint function behaves as a single exponential function and can well be used to determine the stretching parameter. In this paper optimization is sought for a detector embedded in the system, which changes the adjoint function in the detector drastically. From literature it is known that the combination of path length stretching and angular biasing can result in appreciable variance reduction. However, angular biasing is not generally available in general purpose Monte Carlo codes and therefore we want to restrict ourselves to the application of pure path length stretching and finding optimum parameters for that. Nonetheless, the starting point for our research is the zero-variance scheme. In order to study the solution in detail the simplified monoenergetic two-direction model is adopted, which allows analytical solutions and can still be used in a Monte Carlo simulation. Knowing the zero-variance solution analytically, it is shown how optimum path length stretching parameters can be derived from it. It results in path length shrinking in the detector. Results for the variance in the detector response are shown in comparison with other patterns for the stretching parameter. The effect of anisotropic scattering on the path length stretching parameter is taken into account. (author)

Cyclic mechanical stretch enhances BMP9-induced osteogenic differentiation of mesenchymal stem cells.

Science.gov (United States)

Song, Yang; Tang, Yinhong; Song, Jinlin; Lei, Mingxing; Liang, Panpan; Fu, Tiwei; Su, Xudong; Zhou, Pengfei; Yang, Li; Huang, Enyi

2018-04-01

The purpose of this study was to investigate whether mechanical stretch can enhance the bone morphogenetic protein 9 (BMP9)-induced osteogenic differentiation in MSCs. Recombinant adenoviruses were used to overexpress the BMP9 in C3H10T1/2 MSCs. Cells were seeded onto six-well BioFlex collagen I-coated plates and subjected to cyclic mechanical stretch [6% elongation at 60 cycles/minute (1 Hz)] in a Flexercell FX-4000 strain unit for up to 12 hours. Immunostaining and confocal microscope were used to detect cytoskeleton organization. Cell cycle progression was checked by flow cytometry. Alkaline phosphatase activity was measured with a Chemiluminescence Assay Kit and was quantified with a histochemical staining assay. Matrix mineralization was examined by Alizarin Red S Staining. Mechanical stretch induces cytoskeleton reorganization and inhibits cell proliferation by preventing cells entry into S phase of the cell cycle. Although mechanical stretch alone does not induce the osteogenic differentiation of C3H10T1/2 MSCs, co-stimulation with mechanical stretch and BMP9 enhances alkaline phosphatase activity. The expression of key lineage-specific regulators (e.g., osteocalcin (OCN), SRY-related HMG-box 9, and runt-related transcription factor 2) is also increased after the co-stimulation, compared to the mechanical stretch stimulation along. Furthermore, mechanical stretch augments the BMP9-mediated bone matrix mineralization of C3H10T1/2 MSCs. Our results suggest that mechanical stretch enhances BMP9-induced osteoblastic lineage specification in C3H10T1/2 MSCs.

Guaranteed epsilon-optimal treatment plans with the minimum number of beams for stereotactic body radiation therapy

International Nuclear Information System (INIS)

Yarmand, Hamed; Winey, Brian; Craft, David

2013-01-01

Stereotactic body radiation therapy (SBRT) is characterized by delivering a high amount of dose in a short period of time. In SBRT the dose is delivered using open fields (e.g., beam’s-eye-view) known as ‘apertures’. Mathematical methods can be used for optimizing treatment planning for delivery of sufficient dose to the cancerous cells while keeping the dose to surrounding organs at risk (OARs) minimal. Two important elements of a treatment plan are quality and delivery time. Quality of a plan is measured based on the target coverage and dose to OARs. Delivery time heavily depends on the number of beams used in the plan as the setup times for different beam directions constitute a large portion of the delivery time. Therefore the ideal plan, in which all potential beams can be used, will be associated with a long impractical delivery time. We use the dose to OARs in the ideal plan to find the plan with the minimum number of beams which is guaranteed to be epsilon-optimal (i.e., a predetermined maximum deviation from the ideal plan is guaranteed). Since the treatment plan optimization is inherently a multi-criteria-optimization problem, the planner can navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing epsilon-optimality. We use mixed integer programming (MIP) for optimization. To reduce the computation time for the resultant MIP, we use two heuristics: a beam elimination scheme and a family of heuristic cuts, known as ‘neighbor cuts’, based on the concept of ‘adjacent beams’. We show the effectiveness of the proposed technique on two clinical cases, a liver and a lung case. Based on our technique we propose an algorithm for fast generation of epsilon-optimal plans. (paper)

Crustal Stretching Style and Lower Crust Flow of the South China Sea Northern Margin

Science.gov (United States)

Bai, Y.; Dong, D.; Runlin, D.

2017-12-01

There is a controversy about crustal stretching style of the South China Sea (SCS) northern margin mainly due to considerable uncertainty of stretching factor estimation, for example, as much as 40% of upper crust extension (Walsh et al., 1991) would be lost by seismic profiles due to poor resolution. To discover and understand crustal stretching style and lower crustal flow on the whole, we map the Moho and Conrad geometries based on gravity inversion constrained by deep seismic profiles, then according to the assumption of upper and lower crust initial thickness, upper and lower crust stretching factors are estimated. According to the comparison between upper and lower crust stretching factors, the SCS northern margin could be segmented into three parts, (1) sediment basins where upper crust is stretched more than lower crust, (2) COT regions where lower crust is stretched more than upper crust, (3) other regions where the two layers have similar stretching factors. Stretching factor map shows that lower crust flow happened in both of COT and sediment basin regions where upper crust decouples with lower crust due to high temperature. Pressure contrast by sediment loading in basins and erosion in sediment-source regions will lead to lower crust flow away from sediment sink to source. Decoupled and fractured upper crust is stretched further by sediment loading and the following compensation would result in relatively thick lower crust than upper crust. In COT regions with thin sediment coverage, low-viscosity lower crust is easier to thin in extensional environment, also the lower crust tends to flow away induced by magma upwelling. Therefore, continental crust on the margin is not stretching in a constant way but varies with the tectonic setting changes. This work is supported by National Natural Science Foundation of China (Grant No. 41506055, 41476042) and Fundamental Research Funds for the Central Universities China (No.17CX02003A).

Mechanical stretching stimulates collagen synthesis via down-regulating SO2/AAT1 pathway

Science.gov (United States)

Liu, Jia; Yu, Wen; Liu, Yan; Chen, Selena; Huang, Yaqian; Li, Xiaohui; Liu, Cuiping; Zhang, Yanqiu; Li, Zhenzhen; Du, Jie; Tang, Chaoshu; Du, Junbao; Jin, Hongfang

2016-01-01

The aim of the study was to investigate the role of endogenous sulfur dioxide (SO2)/ aspartate aminotransferase 1 (AAT1) pathway in stretch-induced excessive collagen expression and its mechanism. The mechanical stretch downregulated SO2/AAT1 pathway and increased collagen I and III protein expression. Importantly, AAT1 overexpression blocked the increase in collagen I and III expression, transforming growth factor-β1 (TGF- β1) expression and phosphorylation of Smad2/3 induced by stretch, but AAT1 knockdown mimicked the increase in collagen I and III expression, TGF- β1 expression and phosphorylation of Smad2/3 induced by stretch. Mechanistically, SB431542, a TGF-β1/Smad2/3 inhibitor, eliminated excessive collagen I and III accumulation induced by AAT1 knockdown, stretch or stretch plus AAT1 knockdown. In a rat model of high pulmonary blood flow-induced pulmonary vascular collagen accumulation, AAT1 expression and SO2 content in lung tissues of rat were reduced in shunt rats with high pulmonary blood flow. Supplement of SO2 derivatives inhibited activation of TGF- β1/Smad2/3 pathway and alleviated the excessive collagen accumulation in lung tissues of shunt rats. The results suggested that deficiency of endogenous SO2/AAT1 pathway mediated mechanical stretch-stimulated abnormal collagen accumulation via TGF-β1/Smad2/3 pathway. PMID:26880260

Long-term evaluation of degradation and foreign-body reaction of subcutaneously implanted poly(DL-lactide-epsilon-caprolactone)

NARCIS (Netherlands)

denDunnen, WFA; Robinson, PH; vanWessel, R; Pennings, AJ; vanLeeuwen, MBM; Schakenraad, JM

1997-01-01

The aim of this study was to evaluate the degradation and foreign-body reaction of poly(DL-lactide-epsilon-caprolactone) (PLA(85)CL(50)) bars. This specific biomaterial is used for the construction of nerve guides, which can be used in the reconstruction of short nerve gaps. Subcutaneously implanted

DNA analysis by single molecule stretching in nanofluidic biochips

DEFF Research Database (Denmark)

Abad, E.; Juarros, A.; Retolaza, A.

2011-01-01

Imprint Lithography (NIL) technology combined with a conventional anodic bonding of the silicon base and Pyrex cover. Using this chip, we have performed single molecule imaging on a bench-top fluorescent microscope system. Lambda phage DNA was used as a model sample to characterize the chip. Single molecules of λ-DNA......Stretching single DNA molecules by confinement in nanofluidic channels has attracted a great interest during the last few years as a DNA analysis tool. We have designed and fabricated a sealed micro/nanofluidic device for DNA stretching applications, based on the use of the high throughput Nano...... stained with the fluorescent dye YOYO-1 were stretched in the nanochannel array and the experimental results were analysed to determine the extension factor of the DNA in the chip and the geometrical average of the nanochannel inner diameter. The determination of the extension ratio of the chip provides...

Effect of acute stretch injury on action potential and network activity of rat neocortical neurons in culture.

Science.gov (United States)

Magou, George C; Pfister, Bryan J; Berlin, Joshua R

2015-10-22

The basis for acute seizures following traumatic brain injury (TBI) remains unclear. Animal models of TBI have revealed acute hyperexcitablility in cortical neurons that could underlie seizure activity, but studying initiating events causing hyperexcitability is difficult in these models. In vitro models of stretch injury with cultured cortical neurons, a surrogate for TBI, allow facile investigation of cellular changes after injury but they have only demonstrated post-injury hypoexcitability. The goal of this study was to determine if neuronal hyperexcitability could be triggered by in vitro stretch injury. Controlled uniaxial stretch injury was delivered to a spatially delimited region of a spontaneously active network of cultured rat cortical neurons, yielding a region of stretch-injured neurons and adjacent regions of non-stretched neurons that did not directly experience stretch injury. Spontaneous electrical activity was measured in non-stretched and stretch-injured neurons, and in control neuronal networks not subjected to stretch injury. Non-stretched neurons in stretch-injured cultures displayed a three-fold increase in action potential firing rate and bursting activity 30-60 min post-injury. Stretch-injured neurons, however, displayed dramatically lower rates of action potential firing and bursting. These results demonstrate that acute hyperexcitability can be observed in non-stretched neurons located in regions adjacent to the site of stretch injury, consistent with reports that seizure activity can arise from regions surrounding the site of localized brain injury. Thus, this in vitro procedure for localized neuronal stretch injury may provide a model to study the earliest cellular changes in neuronal function associated with acute post-traumatic seizures. Copyright © 2015. Published by Elsevier B.V.

Radiolabelling of isopeptide N epsilon-(gamma-glutamyl)-L-lysine by conjugation with N-succinimidyl-4-[18F]fluorobenzoate.

Science.gov (United States)

Wüst, F; Hultsch, C; Bergmann, R; Johannsen, B; Henle, T

2003-07-01

The isopeptide N(epsilon)-(gamma-glutamyl)-L-lysine 4 was labelled with 18F via N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB). A modified approach for the convenient synthesis of [18F]SFB was used, and [18F]SFB could be obtained in decay-corrected radiochemical yields of 44-53% (n = 20) and radiochemical purity >95% within 40 min after EOB. For labelling N(epsilon)-(gamma-glutamyl)-L-lysine with [18F]SFB the effects of isopeptide concentration, temperature, and pH were studied to determine the optimum reaction conditions. The coupling reaction was shown to be temperature and pH independent while being strongly affected by the isopeptide concentration. Using the optimized labelling conditions, in a typical experiment 1.3GBq of [18F]SFB could be converted into 447MBq (46%, decay-corrected) of [18F]fluorobenzoylated isopeptide within 45 min, including HPLC purification.

The static actuation of dielectric elastomer actuators: how does pre-stretch improve actuation?

International Nuclear Information System (INIS)

Kofod, Guggi

2008-01-01

It has previously been shown that providing dielectric elastomer actuators with a level of pre-stretch can improve properties such as breakdown strength, actuation strain and efficiency. The actuation in such actuators depends on an interplay between the highly nonlinear hyperelastic stress-strain behaviour with the electrostatic Maxwell's stress; however, the direct effects of pre-stretch on the electromechanical coupling have still not been investigated in detail. We compare several experimental results found in the literature on the hyperelastic parameters of the Ogden model for the commonly used material VHB 4910, and introduce a more detailed and thus more accurate fit to a previous uniaxial stress-strain experiment. Electrostatic actuation models for a pure shear cuboid dielectric elastomer actuator with pre-stretch are introduced, for both intensive and extensive variables. For both intensive and extensive variables the constant strain (blocked stress or force) as well as the actuation strain is presented. It is shown how in the particular case of isotropic amorphous elastomers the pre-stretch does not affect the electromechanical coupling directly, and that the enhancement in actuation strain due to pre-stretch occurs through the alteration of the geometrical dimensions of the actuator. Also, the presence of the optimum load is explained as being due to the plateau region in the force-stretch curve, and it is shown that pre-stretch is not able to affect its position. Finally, it is shown how the simplified Ogden fit leads to entirely different conclusions for actuation strain in terms of extensive variables as does the detailed fit, emphasizing the importance of employing accurate hyperelastic models for the stress-stretch behaviour of the elastomer.

Super-resolution with a positive epsilon multi-quantum-well super-lens

International Nuclear Information System (INIS)

Bak, A. O.; Giannini, V.; Maier, S. A.; Phillips, C. C.

2013-01-01

We design an anisotropic and dichroic quantum metamaterial that is able to achieve super-resolution without the need for a negative permittivity. When exploring the parameters of the structure, we take into account the limits of semiconductor fabrication technology based on quantum well stacks. By heavily doping the structure with free electrons, we infer an anisotropic effective medium with a prolate ellipsoid dispersion curve which allows for near-diffractionless propagation of light (similar to an epsilon-near-zero hyperbolic lens). This, coupled with low absorption, allows us to resolve images at the sub-wavelength scale at distances 6 times greater than equivalent natural materials

Preferential emission into epsilon-near-zero metamaterial [Invited

International Nuclear Information System (INIS)

Galfsky, Tal; Sun, Zheng; Jacob, Zubin; Menon, Vinod M.

2015-01-01

We report the use of epsilon near zero (ENZ) metamaterial to control spontaneous emission from Zinc-Oxide (ZnO) excitons. The ENZ material consists of alternating layers of silver and alumina with subwavelength thicknesses, resulting in an effective medium where one of the components of the dielectric constant approach zero between 370nm-440nm wavelength range. Bulk ZnO with photoluminescence maximum in the ENZ regime was deposited via atomic layer deposition to obtain a smooth film with near field coupling to the ENZ metamaterial. Preferential emission from the ZnO layer into the metamaterial with suppression of forward emission by 90% in comparison to ZnO on silicon is observed. We attribute this observation to the presence of dispersionless plasmonic modes in the ENZ regime as shown by the results of theoretical modeling presented here. Integration of ENZ metamaterials with light emitters is an attractive platform for realizing a low threshold subwavelength laser

Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios

Science.gov (United States)

Sekir, Ufuk; Arabaci, Ramiz; Akova, Bedrettin

2015-01-01

AIM: To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps (H/Q) strength ratios in elite women athletes. METHODS: Eleven healthy female athletes in an elite competitive level participated to the study. All the participants fulfilled the static stretching or non-stretching (control) intervention protocol in a randomized design on different days. Two static unassisted stretching exercises, one in standing and one in sitting position, were used to stretch both the hamstring and quadriceps muscles during these protocols. The total time for the static stretching was 6 ± 1 min. The isokinetic peak torque measurements for the hamstring and quadriceps muscles in eccentric and concentric modes and the calculations for the functional H/Q strength ratios at angular velocities of 60°/s and 180°/s were made before (pre) and after (post) the control or stretching intervention. The strength measurements and functional strength ratio calculations were based during the entire- and end-range of knee extension. RESULTS: The pre-test scores for quadriceps and hamstring peak torque and end range values were not significantly different between the groups (P > 0.05). Subsequently, although the control group did not exhibit significant changes in quadriceps and hamstring muscle strength (P > 0.05), static stretching decreased eccentric and concentric quadriceps muscle strength at both the 60°/s and 180°/s test speeds (P hamstring muscle strength at both the 60°/s and 180°/s test speeds (P 0.05). Furthermore, the functional H/Q strength ratios exhibited no significant alterations during the entire and end ranges of knee extension both in the static stretching or the control intervention (P > 0.05). CONCLUSION: According to our results, static stretching routine does not influence functional H/Q ratio. Athletes can confidently perform static stretching during their warm-up routines. PMID:26495249

The effects of static stretch duration on the flexibility of hamstring ...

African Journals Online (AJOL)

The effects of static stretch duration on the flexibility of hamstring muscles. NA Odunaiya, TK Hamzat, OF Ajayi. Abstract. The effects of duration of a static stretching protocol (Intervention) on hamstrings tightness were evaluated. Sixty purposively sampled subjects with unilateral hamstring tightness that had no history of low ...

Triblock copolymers based on epsilon-caprolactone and trimethylene carbonate for the 3D printing of tissue engineering scaffolds

NARCIS (Netherlands)

Guney, Aysun; Malda, Jos; Dhert, Wouter J. A.; Grijpma, Dirk W.

Background: Biodegradable PCL-b-PTMC-b-PCL triblock copolymers based on trimethylene carbonate (TMC) and epsilon-caprolactone (CL) were prepared and used in the 3D printing of tissue engineering scaffolds. Triblock copolymers of various molecular weights containing equal amounts of TMC and CL were

High interobserver variability in the assessment of epsilon waves : Implications for diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia

NARCIS (Netherlands)

Platonov, Pyotr G; Calkins, Hugh; Hauer, Richard N; Corrado, Domenico; Svendsen, Jesper H; Wichter, Thomas; Biernacka, Elżbieta Katarzyna; Saguner, Ardan M; Te Riele, Anneline S J M; Zareba, Wojciech

BACKGROUND: Revision of the Task Force diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) has increased their sensitivity for the diagnosis of early and familial forms of the disease. The epsilon wave is a major diagnostic criterion in the context of ARVC/D,

Mechanical stretch endows mesenchymal stem cells stronger angiogenic and anti-apoptotic capacities via NFκB activation

International Nuclear Information System (INIS)

Zhu, Zhuoli; Gan, Xueqi; Fan, Hongyi; Yu, Haiyang

2015-01-01

Mesenchymal stem cells (MSCs) have been broadly used for tissue regeneration and repair due to their broad differentiation potential and potent paracrine properties such as angiogenic capacity. Strategies to increase their survival rate after transplantation and the angiogenic ability are of priority for the utility of MSCs. In this study, we found that mechanical stretch (10% extension, 30 cycles/min cyclic stretch) preconditioning increase the angiogenic capacity via VEGFA induction. In addition, mechanical stretch also increases the survival rate of mesenchymal stem cells under nutrients deprivation. Consistent with the increase VEGFA expression and resistance to apoptosis, nuclear localization of NFκB activity p65 increased upon mechanical stretch. Inhibition of NFκB activity by BAY 11-708 blocks the pro-angiogenesis and anti-apoptosis function of mechanical stretch. Taken together, our findings here raise the possibility that mechanical stretch preconditioning might enhance the therapeutic efficacy of mesenchymal stem cells. - Highlights: • Mechanical stretch increases the angiogenic capacity via VEGFA induction in MSCs. • Mechanical stretch increases the survival rate of MSCs under nutrients deprivation. • Mechanical stretch manipulates MSCs via the activation of NFκB.

Mechanical stretch endows mesenchymal stem cells stronger angiogenic and anti-apoptotic capacities via NFκB activation

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zhuoli; Gan, Xueqi [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Fan, Hongyi [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Department of Applied Mechanics, College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); Yu, Haiyang, E-mail: yhyang6812@foxmail.com [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China)

2015-12-25

Mesenchymal stem cells (MSCs) have been broadly used for tissue regeneration and repair due to their broad differentiation potential and potent paracrine properties such as angiogenic capacity. Strategies to increase their survival rate after transplantation and the angiogenic ability are of priority for the utility of MSCs. In this study, we found that mechanical stretch (10% extension, 30 cycles/min cyclic stretch) preconditioning increase the angiogenic capacity via VEGFA induction. In addition, mechanical stretch also increases the survival rate of mesenchymal stem cells under nutrients deprivation. Consistent with the increase VEGFA expression and resistance to apoptosis, nuclear localization of NFκB activity p65 increased upon mechanical stretch. Inhibition of NFκB activity by BAY 11-708 blocks the pro-angiogenesis and anti-apoptosis function of mechanical stretch. Taken together, our findings here raise the possibility that mechanical stretch preconditioning might enhance the therapeutic efficacy of mesenchymal stem cells. - Highlights: • Mechanical stretch increases the angiogenic capacity via VEGFA induction in MSCs. • Mechanical stretch increases the survival rate of MSCs under nutrients deprivation. • Mechanical stretch manipulates MSCs via the activation of NFκB.

Probabilistic model of ligaments and tendons: Quasistatic linear stretching

Science.gov (United States)

Bontempi, M.

2009-03-01

Ligaments and tendons have a significant role in the musculoskeletal system and are frequently subjected to injury. This study presents a model of collagen fibers, based on the study of a statistical distribution of fibers when they are subjected to quasistatic linear stretching. With respect to other methodologies, this model is able to describe the behavior of the bundle using less ad hoc hypotheses and is able to describe all the quasistatic stretch-load responses of the bundle, including the yield and failure regions described in the literature. It has two other important results: the first is that it is able to correlate the mechanical behavior of the bundle with its internal structure, and it suggests a methodology to deduce the fibers population distribution directly from the tensile-test data. The second is that it can follow fibers’ structure evolution during the stretching and it is possible to study the internal adaptation of fibers in physiological and pathological conditions.

Stretching of red blood cells at high strain rates

Science.gov (United States)

Mancuso, J. E.; Ristenpart, W. D.

2017-10-01

Most work on the mechanical behavior of red blood cells (RBCs) in flow has focused on simple shear flows. Relatively little work has examined RBC deformations in the physiologically important extensional flow that occurs at the entrance to a constriction. In particular, previous work suggests that RBCs rapidly stretch out and then retract upon entering the constriction, but to date no model predicts this behavior for the extremely high strain rates typically experienced there. In this Rapid Communication, we use high speed video to perform systematic measurements of the dynamic stretching behavior of RBCs as they enter a microfluidic constriction. We demonstrate that both the Kelvin-Voigt and Skalak viscoelastic models capture the observed stretching dynamics, up to strain rates as high as 2000 s-1. The results indicate that the effective elastic modulus of the RBC membrane at these strain rates is an order of magnitude larger than moduli measured by micropipette aspiration or other low strain rate techniques.

Filament stretching rheometry of polymer melts

DEFF Research Database (Denmark)

Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

2005-01-01

The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

Muscle oxygenation and fascicle length during passive muscle stretching in ballet-trained subjects.

Science.gov (United States)

Otsuki, A; Fujita, E; Ikegawa, S; Kuno-Mizumura, M

2011-07-01

Muscle stretching transiently decreases muscle-blood flow corresponding to a muscle extension. It may disturb a balance between muscular oxygen demand and oxygen supply to muscles and reduce muscle oxygenation. However, muscle-stretching training may improve blood circulatory condition, resulting in the maintained muscle oxygenation during muscle stretching. The aim of this study was to investigate changes in muscle-blood volume (tHb) and tissue oxygenation index (TOI) during muscle stretching determined by using near-infrared spectroscopy (NIRS) in ballet-trained (BT) and untrained (C) subjects. 11 BT women who regularly perform muscle stretching and 11 C women participated in this study. Fascicle lengths, tHb and TOI in the tibialis anterior muscle were measured during passive plantar flexion from ankle joint angles of 120° (baseline) to 140°, 160°, the maximal comfortable position without pain (CP), and the maximal position (MP). At 160°, the % fascicle-length change from baseline was significantly lower in the BT than the C group, however, for the changes in tHb and TOI the significant interaction effect between the 2 groups was not detected. On the other hand, although the increases in the fascicle length from baseline to CP and MP were greater in BT than C, the tHb and TOI reductions were comparable between groups. We concluded that it appears that BT can extend their muscles without excessive reduction in muscle-blood volume and muscle oxygenation at relatively same but absolutely greater muscle-stretching levels than C. The attenuation in these indices during high-level muscle stretching may be associated with the repetitive muscle stretching of long-term ballet training. © Georg Thieme Verlag KG Stuttgart · New York.

Effects of Combining Running and Practical Duration Stretching on Proprioceptive Skills of National Sprinters.

Science.gov (United States)

Romero-Franco, Natalia; Párraga-Montilla, Juan Antonio; Molina-Flores, Enrique M; Jiménez-Reyes, Pedro

2018-06-01

Romero-Franco, N, Párraga-Montilla, JA, Molina-Flores, EM, and Jiménez-Reyes, P. Effects of combining running and practical duration stretching on proprioceptive skills of national sprinters. J Strength Cond Res XX(X): 000-000, 2018-Practical duration stretching after aerobic activities is a recommended component of the first part of warm-up because of its effects on performance. However, its effects on proprioceptive skills are unknown. This study aimed to analyze the effects of running and practical duration static stretching (SS) and dynamic stretching (DS) on postural balance and the joint position sense (JPS) of national sprinters. Thirty-two national sprinters were randomly classified into a SS group (n = 11), DS group (n = 11), or control group (n = 10). Static stretching performed 5 minutes of running and short-duration (20 seconds) static stretches; DS performed 5 minutes of running and short-duration dynamic (20 seconds) stretches; and the control group performed 5 minutes of running. Before and after the intervention, unipedal static postural balance and knee JPS were evaluated. Static stretching exhibited a more centralized center of pressure in the medial-lateral plane for unipedal static postural balance in right-leg support after stretching (p = 0.005, d = 1.24), whereas DS showed values further from the center after stretching for the same unipedal support compared with baseline (p = 0.042, d = 0.49), and the control group remained stable (p > 0.05). Joint position sense did not show significant differences in any group (p > 0.05). In conclusion, combining running and practical duration SS may be beneficial for right-leg postural stabilization, whereas DS may be partly and slightly deleterious. Both SS and DS combined with running and running alone have neutral effects on knee JPS. Sports professionals should consider running and practical duration SS as part of the warm-up of sprinters to partly improve unipedal static postural balance.

Caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress.

Science.gov (United States)

Zhang, Qiang; Liu, Jianing; Chen, Shulan; Liu, Jing; Liu, Lijuan; Liu, Guirong; Wang, Fang; Jiang, Wenxin; Zhang, Caixia; Wang, Shuangyu; Yuan, Xiao

2016-04-01

It is well recognized that mandibular growth, which is caused by a variety of functional appliances, is considered to be the result of both neuromuscular and skeletal adaptations. Accumulating evidence has demonstrated that apoptosis plays an important role in the adaptation of skeletal muscle function. However, the underlying mechanism of apoptosis that is induced by stretch continues to be incompletely understood. Endoplasmic reticulum stress (ERS), a newly defined signaling pathway, initiates apoptosis. This study seeks to determine if caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress in myoblast and its underlying mechanism. Apoptosis was assessed by Hochest staining, DAPI staining and annexin V binding and PI staining. ER chaperones, such as GRP78, CHOP and caspase-12, were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Furthermore, caspase-12 inhibitor was used to value the mechanism of the caspase-12 pathway. Apoptosis of myoblast, which is subjected to cyclic stretch, was observed in a time-dependent manner. We found that GRP78 mRNA and protein were significantly increased and CHOP and caspase-12 were activated in myoblast that was exposed to cyclic stretch. Caspase-12 inhibition reduced stretch-induced apoptosis, and caspase-12 activated caspase-3 to induce apoptosis. We concluded that caspase-12 played an important role in stretch-induced apoptosis that is associated by endoplasmic reticulum stress by activating caspase-3.

Star-shaped poly[(trimethylene carbonate)-co-(epsilon-caprolactone)] and its block copolymers with lactide/glycolide : synthesis, characterization and properties

NARCIS (Netherlands)

Joziasse, CAP; Grablowitz, H; Pennings, AJ

Linear and star-shaped copolymers of trimethylene carbonat/epsilon-caprolactone were synthesized using different polyol initiators and catalysts. Unexpectedly, when dipentaerythritol was used as an initiator cross-linked rubbers were obtained, that swell in chlorofonn. This network formation can be

Influence of acute static stretching on the behavior of maximum muscle strength

Directory of Open Access Journals (Sweden)

Carmen Lúcia Borges Bastos

2014-06-01

Full Text Available The aim of this study was to compare the influence of acute static stretching on maximal muscle strength (1RM. The non-probabilistic sample consisted of 30 subjects split into two groups: static stretching (SS= 15 and without stretching group (WS= 15. Muscle strength evaluation (1RM was conducted with a Dynamometer model 32527pp400 Pound push / pull devices coupled in knee extension (KE and bench press (BP. The Wilcoxon test for intragroup comparisons and the Kruskal-Wallis test for comparisons between groups (p< 0.05 were selected. There were no significant differences (p> 0.05 between the SS and WS in exercise KE and BP. Therefore, it can be concluded that there was no reduction in the performance of 1RM performing the exercises KE and BP when preceded by static stretching.

From Static Stretching to Dynamic Exercises: Changing the Warm-Up Paradigm

Science.gov (United States)

Young, Shawna

2010-01-01

In the United States, pre-exercise static stretching seems to have become common practice and routine. However, research suggests that it is time for a paradigm shift--that pre-exercise static stretching be replaced with dynamic warm-up exercises. Research indicates that a dynamic warm-up elevates body temperature, decreases muscle and joint…

Conjugate Heat Transfer of Mixed Convection for Viscoelastic Fluid Past a Stretching Sheet

Directory of Open Access Journals (Sweden)

Kai-Long Hsiao

2007-01-01

Full Text Available A conjugate heat transfer problem of a second-grade viscoelastic fluid past a stretching sheet has been studied. Governing equations include heat conduction equation of a stretching sheet, continuity equation, momentum equation, and energy equation of a second-grade fluid, analyzed by a combination of a series expansion method, the similarity transformation, and a second-order accurate finite-difference method. These solutions are used to iterate with the heat conduction equation of the stretching sheet to obtain distributions of the local convective heat transfer coefficient and the stretching sheet temperature. Ranges of dimensionless parameters, the Prandtl number Pr, the elastic number E and the conduction-convection coefficient Ncc are from 0.001 to 10, 0.0001 to 0.01, and 0.5 to 2.0, respectively. A parameter G, which is used to represent the dominance of the buoyant effect, is present in governing equations. Results indicated that elastic effect in the flow could increase the local heat transfer coefficient and enhance the heat transfer of a stretching sheet. In addition, same as the results from Newtonian fluid flow and conduction analysis of a stretching sheet, a better heat transfer is obtained with a larger Ncc, G, and E.

Cross-bridge mechanism of residual force enhancement after stretching in a skeletal muscle.

Science.gov (United States)

Tamura, Youjiro

2018-01-01

A muscle model that uses a modified Langevin equation with actomyosin potentials was used to describe the residual force enhancement after active stretching. Considering that the new model uses cross-bridge theory to describe the residual force enhancement, it is different from other models that use passive stretching elements. Residual force enhancement was simulated using a half sarcomere comprising 100 myosin molecules. In this paper, impulse is defined as the integral of an excess force from the steady isometric force over the time interval for which a stretch is applied. The impulse was calculated from the force response due to fast and slow muscle stretches to demonstrate the viscoelastic property of the cross-bridges. A cross-bridge mechanism was proposed as a way to describe the residual force enhancement on the basis of the impulse results with reference to the compliance of the actin filament. It was assumed that the period of the actin potential increased by 0.5% and the amplitude of the potential decreased by 0.5% when the half sarcomere was stretched by 10%. The residual force enhancement after 21.0% sarcomere stretching was 6.9% of the maximum isometric force of the muscle; this value was due to the increase in the number of cross-bridges.

Barriers to performing stretching exercises among Korean-Chinese female migrant workers in Korea.

Science.gov (United States)

Lee, Hyeonkyeong; Wilbur, JoEllen; Chae, Duckhee; Lee, Kyongeun; Lee, Meenhye

2015-01-01

The purpose of this study was to investigate the barriers to performing stretching exercise experienced by Korean-Chinese female migrant workers during a community-based 12-week stretching exercise intervention trial. Qualitative secondary data analysis was conducted using telephone counseling interview transcripts from 27 middle-aged, Korean-Chinese migrant women workers. A semistructured interview question asking barriers to performing stretching exercise was given to women who did not adhere to recommended stretching exercise. During the 12-week home-based stretching exercise intervention trial, six telephone calls were made to participants biweekly to elicit barriers to performing stretching exercise. Directed content analysis approach was utilized using three barrier categories: intrapersonal, interpersonal, and work-related environmental factors based on the ecological model. Participants experienced an average of 2.5 barriers during the study period. Intrapersonal barriers included lack of time and lack of motivation, and interpersonal barriers included no family to provide support and also a feeling resistance from coworkers. Work-related environmental barriers included frequent job changes, long working hours, lack of rest time, and unpredictable job demands. The findings highlight that migrant workers in Korea face unique work-related difficulties which present barriers to exercise. © 2014 Wiley Periodicals, Inc.

Individually programmable cell stretching microwell arrays actuated by a Braille display.

Science.gov (United States)

Kamotani, Yoko; Bersano-Begey, Tommaso; Kato, Nobuhiro; Tung, Yi-Chung; Huh, Dongeun; Song, Jonathan W; Takayama, Shuichi

2008-06-01

Cell culture systems are often static and are therefore nonphysiological. In vivo, many cells are exposed to dynamic surroundings that stimulate cellular responses in a process known as mechanotransduction. To recreate this environment, stretchable cell culture substrate systems have been developed, however, these systems are limited by being macroscopic and low throughput. We have developed a device consisting of 24 miniature cell stretching chambers with flexible bottom membranes that are deformed using the computer-controlled, piezoelectrically actuated pins of a Braille display. We have also developed efficient image capture and analysis protocols to quantify morphological responses of the cells to applied strain. Human dermal microvascular endothelial cells (HDMECs) were found to show increasing degrees of alignment and elongation perpendicular to the radial strain in response to cyclic stretch at increasing frequencies of 0.2, 1, and 5 Hz, after 2, 4, and 12h. Mouse myogenic C2C12 cells were also found to align in response to the stretch, while A549 human lung adenocarcinoma epithelial cells did not respond to stretch.

To Stretch and Search for Better Ways

Science.gov (United States)

Moore, John W.

2000-06-01

There's a lot to do to get each issue of this Journal ready for publication, and there's a lot that can go awry during that process. We the editorial staff do our utmost to make certain that each issue is the best it can possibly be, but, of necessity, a lot of our effort is focused on solving problems, correcting errors, and avoiding pitfalls. It is not surprising that we sometimes lose sight of the bigger picture--all of the things that came out as well as or better than we hoped they would. Therefore it gives us great pleasure when a reader applauds (and thereby rewards) our efforts. One such communication inspired this editorial. I have appreciated the extra effort put forward by the staff to make the Journal really come alive. The high quality of the Journal serves as an incentive to chemical educators to stretch and search for better ways to inspire our students. I fervently hope that we do encourage you "to stretch and search for better ways", not only to inspire students but in everything you do. Stretching and searching for better ways is what life, science, chemistry, and teaching are all about, and it is a wonderfully stimulating and exciting way to approach anything and everything. Sometimes, though, one's ability to stretch is akin to that of a rubber band exposed too long to sunlight. Change becomes a threat or a burden instead of an opportunity. This often happens in one area but not others, as in the case of someone doing original research but whose lecture notes are yellow with age, or someone who experiments with new teaching approaches but neglects the latest chemical discoveries. Whatever its manifestation, failure to stretch and search for better ways is a great loss, both for the individual directly involved and for others. Fortunately there are many who continually stretch and search, often in conjunction with JCE. For example, some time ago the Chair of the Board of Publication, Jerry Bell, challenged Journal readers to become Journal

Transferable antibiotic resistance plasmids from biogas plant digestates often belong to the IncP-1 epsilon subgroup

Czech Academy of Sciences Publication Activity Database

Wolters, B.; Kyselková, Martina; Krögerrecklenfort, E.; Kreuzig, R.; Smalla, K.

2015-01-01

Roč. 5, January (2015), Article 765 ISSN 1664-302X R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : IncP-1 epsilon plasmid * class 1 integrons * biogas plant digestate * antibiotic resistance * exogenous plasmid isolation Subject RIV: EE - Microbiology, Virology Impact factor: 4.165, year: 2015

Effectiveness of Manual Therapy and Stretching for Baseball Players With Shoulder Range of Motion Deficits.

Science.gov (United States)

Bailey, Lane B; Thigpen, Charles A; Hawkins, Richard J; Beattie, Paul F; Shanley, Ellen

Baseball players displaying deficits in shoulder range of motion (ROM) are at increased risk of arm injury. Currently, there is a lack of consensus regarding the best available treatment options to restore shoulder ROM. Instrumented manual therapy with self-stretching will result in clinically significant deficit reductions when compared with self-stretching alone. Controlled laboratory study. Shoulder ROM and humeral torsion were assessed in 60 active baseball players (mean age, 19 ± 2 years) with ROM deficits (nondominant - dominant, ≥15°). Athletes were randomly assigned to receive a single treatment of instrumented manual therapy plus self-stretching (n = 30) or self-stretching only (n = 30). Deficits in internal rotation, horizontal adduction, and total arc of motion were compared between groups immediately before and after a single treatment session. Treatment effectiveness was determined by mean comparison data, and a number-needed-to-treat (NNT) analysis was used for assessing the presence of ROM risk factors. Prior to intervention, players displayed significant ( P < 0.001) dominant-sided deficits in internal rotation (-26°), total arc of motion (-18°), and horizontal adduction (-17°). After the intervention, both groups displayed significant improvements in ROM, with the instrumented manual therapy plus self-stretching group displaying greater increases in internal rotation (+5°, P = 0.010), total arc of motion (+6°, P = 0.010), and horizontal adduction (+7°, P = 0.004) compared with self-stretching alone. For horizontal adduction deficits, the added use of instrumented manual therapy with self-stretching decreased the NNT to 2.2 (95% CI, 2.1-2.4; P = 0.010). Instrumented manual therapy with self-stretching significantly reduces ROM risk factors in baseball players with motion deficits when compared with stretching alone. The added benefits of manual therapy may help to reduce ROM deficits in clinical scenarios where stretching alone is

[Current trends in the effects of stretching: application to physical exercise in the workplace].

Science.gov (United States)

Eguchi, Yasumasa; Ohta, Masanori; Yamato, Hiroshi

2011-09-01

A review of the Survey on the State of Employees' Health by the Ministry of Health, Labour and Welfare (2008) shows that the most commonly implemented aspect as an activity of worksite health promotion is "Health counseling", and the second is "Workplace physical exercise." Physical exercise, "Taiso", is acceptable and sustainable for workers, as it is easy to do in a group or alone. Various modes of stretching are implemented for workplace physical exercise. However, articles suggesting negative or contradictory effects of stretching have increased in recent years. Several review articles have revealed that static stretching may induce impairments of muscle power performance and no stretching will prevent or reduce muscle soreness after exercise. There are various aims of workplace physical exercise, so we have to consider the situational method when we apply stretching to occupational health.

Achieving highly efficient and broad-angle polarization beam filtering using epsilon-near-zero metamaterials mimicked by metal-dielectric multilayers

Science.gov (United States)

Wu, Feng

2018-03-01

We report a highly efficient and broad-angle polarization beam filter at visible wavelengths using an anisotropic epsilon-near-zero metamaterial mimicked by a multilayer composed of alternative subwavelength magnesium fluoride and silver layers. The underlying physics can be explained by the dramatic difference between two orthogonal polarizations' iso-frequency curves of anisotropic epsilon-near-zero metamaterials. Transmittance for two orthogonal polarization waves and the polarization extinction ratio are calculated via the transfer matrix method to assess the comprehensive performance of the proposed polarization beam filter. From the simulation results, the proposed polarization beam filter is highly efficient (the polarization extinction ratio is far larger than two orders of magnitude) and has a broad operating angle range (ranging from 30° to 75°). Finally, we show that the proper tailoring of the periodic number enables us to obtain high comprehensive performance of the proposed polarization beam filter.

Effectiveness of passive stretching versus hold relax technique in flexibility of hamstring muscle

Directory of Open Access Journals (Sweden)

Gauri Shankar

2010-10-01

Full Text Available Aim: To compare the effectiveness of passive stretching and hold relax technique in the flexibility of hamstring muscle. Methods: A total of 80 normal healthy female subjects between age group 20-30 years referred to the department of physiotherapy, Sumandeep Vidyapeeth University, sampling method being convenient sampling. The subjects were randomly divided in two groups i.e. passive stretching group (n=40 and PNF group (n=40 and given passive stretching and proprioceptive neuromuscular facilitation technique respectively. Active knee extension range was measured before and after the intervention by goniometer. Results: t test showed a highly significant (p=0.000 increase in range of motion in PNF group. Conclusion: Proprioceptive neuromuscular facilitation technique is more effective in increasing hamstring flexibility than the passive stretching.

Stellar model chromospheres. VIII - 70 Ophiuchi A /K0 V/ and Epsilon Eridani /K2 V/

Science.gov (United States)

Kelch, W. L.

1978-01-01

Model atmospheres for the late-type active-chromosphere dwarf stars 70 Oph A and Epsilon Eri are computed from high-resolution Ca II K line profiles as well as Mg II h and k line fluxes. A method is used which determines a plane-parallel homogeneous hydrostatic-equilibrium model of the upper photosphere and chromosphere which differs from theoretical models by lacking the constraint of radiative equilibrium (RE). The determinations of surface gravities, metallicities, and effective temperatures are discussed, and the computational methods, model atoms, atomic data, and observations are described. Temperature distributions for the two stars are plotted and compared with RE models for the adopted effective temperatures and gravities. The previously investigated T min/T eff vs. T eff relation is extended to Epsilon Eri and 70 Oph A, observed and computed Ca II K and Mg II h and k integrated emission fluxes are compared, and full tabulations are given for the proposed models. It is suggested that if less than half the observed Mg II flux for the two stars is lost in noise, the difference between an active-chromosphere star and a quiet-chromosphere star lies in the lower-chromospheric temperature gradient.

Prolonged passive static stretching-induced innervation zone shift in biceps brachii.

Science.gov (United States)

Ye, Xin; Beck, Travis W; Wages, Nathan P

2015-05-01

The purpose of this study was to examine the influence of a bout of repeated and prolonged passive static stretching on the innervation zone (IZ) location of the human biceps brachii muscle. Eleven men performed 12 sets of 100-s passive stretches on their biceps brachii. Before (Pre) and immediately after (Post) the stretching intervention, isometric strength was tested during the maximal voluntary contractions (MVCs) of the forearm flexors. The subjects also performed several separate isometric forearm flexion muscle actions at 30%, 50%, and 70% of their predetermined MVCs for examining the locations of the IZ at different contraction intensities. The IZ was identified through multi-channel surface electromyographic (EMG) recordings from a linear electrode array. The stretching intervention induced an average of 10% isometric strength loss for the forearm flexors (mean±SD: Pre-MVC vs. Post-MVC=332.12±59.40 N vs. 299.53±70.51 N; p<0.001). In addition, the average IZ shift was nearly 4.5 mm in average in the proximal direction. However, this shift was not specific to the contraction intensity. We believe that the IZ shift was caused by the elongation of the entire muscle-tendon unit in the proximal direction. Therefore, caution should be taken when using surface EMG technique to examine possible changes in the EMG variables after a stretching protocol, as these variables can be contaminated by the shift of the IZ.

Intraplaque stretch in carotid atherosclerotic plaque--an effective biomechanical predictor for subsequent cerebrovascular ischemic events.

Directory of Open Access Journals (Sweden)

Zhongzhao Teng

Full Text Available BACKGROUND: Stretch is a mechanical parameter, which has been proposed previously to affect the biological activities in different tissues. This study explored its utility in determining plaque vulnerability. METHODS: One hundred and six patients with mild to moderate carotid stenosis were recruited in this study (53 symptomatic and 53 asymptomatic. High resolution, multi-sequence magnetic resonance (MR imaging was performed to delineate various plaque components. Finite element method was used to predict high stretch concentration within the plaque. RESULTS: During a two-year follow-up, 11 patients in symptomatic group and 3 in asymptomatic group experienced recurrent cerebrovascular events. Plaque stretch at systole and stretch variation during one cardiac cycle was greater in symptomatic group than those in the asymptomatic. Within the symptomatic group, a similar trend was observed in patients with recurrent events compared to those without. CONCLUSION: Plaques with high stretch concentration and large stretch variation are associated with increased risk of future cerebrovascular events.

Biochemical analysis of force-sensitive responses using a large-scale cell stretch device.

Science.gov (United States)

Renner, Derrick J; Ewald, Makena L; Kim, Timothy; Yamada, Soichiro

2017-09-03

Physical force has emerged as a key regulator of tissue homeostasis, and plays an important role in embryogenesis, tissue regeneration, and disease progression. Currently, the details of protein interactions under elevated physical stress are largely missing, therefore, preventing the fundamental, molecular understanding of mechano-transduction. This is in part due to the difficulty isolating large quantities of cell lysates exposed to force-bearing conditions for biochemical analysis. We designed a simple, easy-to-fabricate, large-scale cell stretch device for the analysis of force-sensitive cell responses. Using proximal biotinylation (BioID) analysis or phospho-specific antibodies, we detected force-sensitive biochemical changes in cells exposed to prolonged cyclic substrate stretch. For example, using promiscuous biotin ligase BirA* tagged α-catenin, the biotinylation of myosin IIA increased with stretch, suggesting the close proximity of myosin IIA to α-catenin under a force bearing condition. Furthermore, using phospho-specific antibodies, Akt phosphorylation was reduced upon stretch while Src phosphorylation was unchanged. Interestingly, phosphorylation of GSK3β, a downstream effector of Akt pathway, was also reduced with stretch, while the phosphorylation of other Akt effectors was unchanged. These data suggest that the Akt-GSK3β pathway is force-sensitive. This simple cell stretch device enables biochemical analysis of force-sensitive responses and has potential to uncover molecules underlying mechano-transduction.

Evaluation of functional nerve recovery after reconstruction with a new biodegradable poly (DL-lactide-epsilon-caprolactone) nerve guide

NARCIS (Netherlands)

Meek, MF; denDunnen, WFA; Robinson, PH; Pennings, AJ; Schakenraad, JM

The aim of this study was to evaluate functional nerve recovery following reconstruction of a 1 cm gap in the sciatic nerve of a rat, using a new biodegradable p (DLLA-epsilon-CL) nerve guide. To evaluate both motor and sensory nerve recovery, walking track analysis and electrostimulation tests were

Developmental axon stretch stimulates neuron growth while maintaining normal electrical activity, intracellular calcium flux, and somatic morphology.

Science.gov (United States)

Loverde, Joseph R; Pfister, Bryan J

2015-01-01

Elongation of nerve fibers intuitively occurs throughout mammalian development, and is synchronized with expansion of the growing body. While most tissue systems enlarge through mitosis and differentiation, elongation of nerve fibers is remarkably unique. The emerging paradigm suggests that axons undergo stretch as contiguous tissues enlarge between the proximal and distal segments of spanning nerve fibers. While stretch is distinct from growth, tension is a known stimulus which regulates the growth of axons. Here, we hypothesized that the axon stretch-growth process may be a natural form of injury, whereby regenerative processes fortify elongating axons in order to prevent disconnection. Harnessing the live imaging capability of our axon stretch-growth bioreactors, we assessed neurons both during and following stretch for biomarkers associated with injury. Utilizing whole-cell patch clamp recording, we found no evidence of changes in spontaneous action potential activity or degradation of elicited action potentials during real-time axon stretch at strains of up to 18% applied over 5 min. Unlike traumatic axonal injury, functional calcium imaging of the soma revealed no shifts in free intracellular calcium during axon stretch. Finally, the cross-sectional areas of nuclei and cytoplasms were normal, with no evidence of chromatolysis following week-long stretch-growth limited to the lower of 25% strain or 3 mm total daily stretch. The neuronal growth cascade coupled to stretch was concluded to be independent of the changes in membrane potential, action potential generation, or calcium flux associated with traumatic injury. While axon stretch-growth is likely to share overlap with regenerative processes, we conclude that developmental stretch is a distinct stimulus from traumatic axon injury.

Developmental Axon Stretch Stimulates Neuron Growth While Maintaining Normal Electrical Activity, Intracellular Calcium Flux, and Somatic Morphology

Directory of Open Access Journals (Sweden)

Joseph R Loverde

2015-08-01

Full Text Available Elongation of nerve fibers intuitively occurs throughout mammalian development, and is synchronized with expansion of the growing body. While most tissue systems enlarge through mitosis and differentiation, elongation of nerve fibers is remarkably unique. The emerging paradigm suggests that axons undergo stretch as contiguous tissues enlarge between the proximal and distal segments of spanning nerve fibers. While stretch is distinct from growth, tension is a known stimulus which regulates the growth of axons. Here, we hypothesized that the axon stretch-growth process may be a natural form of injury, whereby regenerative processes fortify elongating axons in order to prevent disconnection. Harnessing the live imaging capability of our axon stretch-growth bioreactors, we assessed neurons both during and following stretch for biomarkers associated with injury. Utilizing whole-cell patch clamp recording, we found no evidence of changes in spontaneous action potential activity or degradation of elicited action potentials during real-time axon stretch at strains of up to 18 % applied over 5 minutes. Unlike traumatic axonal injury, functional calcium imaging of the soma revealed no shifts in free intracellular calcium during axon stretch. Finally, the cross-sectional areas of nuclei and cytoplasms were normal, with no evidence of chromatolysis following week-long stretch-growth limited to the lower of 25 % strain or 3 mm total daily stretch. The neuronal growth cascade coupled to stretch was concluded to be independent of the changes in membrane potential, action potential generation, or calcium flux associated with traumatic injury. While axon stretch-growth is likely to share overlap with regenerative processes, we conclude that developmental stretch is a distinct stimulus from traumatic axon injury.

Retosiban Prevents Stretch-Induced Human Myometrial Contractility and Delays Labor in Cynomolgus Monkeys.

Science.gov (United States)

Aye, Irving L M H; Moraitis, Alexandros A; Stanislaus, Dinesh; Charnock-Jones, D Stephen; Smith, Gordon C S

2018-03-01

Stretch of the myometrium promotes its contractility and is believed to contribute to the control of parturition at term and to the increased risk of preterm birth in multiple pregnancies. To determine the effects of the putative oxytocin receptor (OTR) inverse agonist retosiban on (1) the contractility of human myometrial explants and (2) labor in nonhuman primates. Human myometrial biopsies were obtained at planned term cesarean, and explants were exposed to stretch in the presence and absence of a range of drugs, including retosiban. The in vivo effects of retosiban were determined in cynomolgus monkeys. Prolonged mechanical stretch promoted myometrial extracellular signal-regulated kinase (ERK)1/2 phosphorylation. Moreover, stretch-induced stimulation of myometrial contractility was prevented by ERK1/2 inhibitors. Retosiban (10 nM) prevented stretch-induced stimulation of myometrial contractility and phosphorylation of ERK1/2. Moreover, the inhibitory effect of retosiban on stretch-induced ERK1/2 phosphorylation was prevented by coincubation with a 100-fold excess of a peptide OTR antagonist, atosiban. Compared with vehicle-treated cynomolgus monkeys, treatment with oral retosiban (100 to 150 days of gestational age) reduced the risk of spontaneous delivery (hazard ratio = 0.07, 95% confidence interval 0.01 to 0.60, P = 0.015). The OTR acts as a uterine mechanosensor, whereby stretch increases myometrial contractility through agonist-free activation of the OTR. Retosiban prevents this through inverse agonism of the OTR and, in vivo, reduced the likelihood of spontaneous labor in nonhuman primates. We hypothesize that retosiban may be an effective preventative treatment of preterm birth in high-risk multiple pregnancies, an area of unmet clinical need.

Kink and kink-like waves in pre-stretched Mooney-Rivlin viscoelastic rods

Directory of Open Access Journals (Sweden)

Y. Z. Wang

2015-08-01

Full Text Available The present paper theoretically investigates kink and kink-like waves propagating in pre-stretched Mooney-Rivlin viscoelastic rods. In the constitutive modeling, the Cauchy stress tensor is assumed to consist of an elastic part and a dissipative part. The asymptotic method is adopted to simplify the nonlinear dynamic equations in the limit of finite-small amplitude and long wavelength. Using the reductive perturbation method, we further derive the well-known far-field equation (i.e. the KdV-Burgers equation, to which two kinds of explicit traveling wave solutions are presented. Examples are given to show the influences of pre-stretch and viscosity on the wave shape and wave velocity. It is shown that pre-stretch could be an effective method for modulating the two types of waves. In addition, such waves may be utilized to measure the viscosity coefficient of the material. The competition between the effects of pre-stretch and viscosity on the kink and kink-like waves is also revealed.

Cell volume and membrane stretch independently control K+ channel activity

DEFF Research Database (Denmark)

Bomholtz, Sofia Hammami; Willumsen, Niels J; Olsen, Hervør L

2009-01-01

A number of potassium channels including members of the KCNQ family and the Ca(2+) activated IK and SK, but not BK, are strongly and reversibly regulated by small changes in cell volume. It has been argued that this general regulation is mediated through sensitivity to changes in membrane stretch...... was not affected by membrane stretch. The results indicate that (1) activation of BK channels by local membrane stretch is not mimicked by membrane stress induced by cell swelling, and (2) activation of KCNQ1 channels by cell volume increase is not mediated by local tension in the cell membrane. We conclude....... To test this hypothesis we have studied the regulation of KCNQ1 and BK channels after expression in Xenopus oocytes. Results from cell-attached patch clamp studies (approximately 50 microm(2) macropatches) in oocytes expressing BK channels demonstrate that the macroscopic volume-insensitive BK current...

Linear response of stretch-affected premixed flames to flow oscillations

Energy Technology Data Exchange (ETDEWEB)

Wang, H.Y.; Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Lieuwen, T. [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2009-04-15

The linear response of 2D wedge-shaped premixed flames to harmonic velocity disturbances was studied, allowing for the influence of flame stretch manifested as variations in the local flame speed along the wrinkled flame front. Results obtained from analyzing the G-equation show that the flame response is mainly characterized by a Markstein number {sigma}{sub C}, which measures the curvature effect of the wrinkles, and a Strouhal number, St{sub f}, defined as the angular frequency of the disturbance normalized by the time taken for the disturbance to propagate the flame length. Flame stretch is found to become important when the disturbance frequency satisfies {sigma}{sub C}St{sub f}{sup 2}{proportional_to} O(1), i.e. St{sub f}{proportional_to} O({sigma}{sub C}{sup -1/2}). Specifically, for disturbance frequencies below this order, stretch effects are small and the flame responds as an unstretched one. When the disturbance frequencies are of this order, the transfer function, defined as the ratio of the normalized fluctuation of the heat release rate to that of the velocity, is contributed mostly from fluctuations of the flame surface area, which is now affected by stretch. Finally, as the disturbance frequency increases to St{sub f}{proportional_to} O({sigma}{sub C}{sup -1}), i.e. {sigma}{sub C}St{sub f}{proportional_to} O(1), the direct contribution from the stretch-affected flame speed fluctuation to the transfer function becomes comparable to that of the flame surface area. The present study phenomenologically explains the experimentally observed filtering effect in which the flame wrinkles developed at the flame base decay along the flame surface for large frequency disturbances as well as for thermal-diffusively stable and weakly unstable mixtures. (author)

The Effect of Static Stretch on Elastin Degradation in Arteries

Science.gov (United States)

Chow, Ming-Jay; Choi, Myunghwan; Yun, Seok Hyun; Zhang, Yanhang

2013-01-01

Previously we have shown that gradual changes in the structure of elastin during an elastase treatment can lead to important transition stages in the mechanical behavior of arteries [1]. However, in vivo arteries are constantly being loaded due to systolic and diastolic pressures and so understanding the effects of loading on the enzymatic degradation of elastin in arteries is important. With biaxial tensile testing, we measured the mechanical behavior of porcine thoracic aortas digested with a mild solution of purified elastase (5 U/mL) in the presence of a static stretch. Arterial mechanical properties and biochemical composition were analyzed to assess the effects of mechanical stretch on elastin degradation. As elastin is being removed, the dimensions of the artery increase by more than 20% in both the longitude and circumference directions. Elastin assays indicate a faster rate of degradation when stretch was present during the digestion. A simple exponential decay fitting confirms the time constant for digestion with stretch (0.11±0.04 h−1) is almost twice that of digestion without stretch (0.069±0.028 h−1). The transition from J-shaped to S-shaped stress vs. strain behavior in the longitudinal direction generally occurs when elastin content is reduced by about 60%. Multiphoton image analysis confirms the removal/fragmentation of elastin and also shows that the collagen fibers are closely intertwined with the elastin lamellae in the medial layer. After removal of elastin, the collagen fibers are no longer constrained and become disordered. Release of amorphous elastin during the fragmentation of the lamellae layers is observed and provides insights into the process of elastin degradation. Overall this study reveals several interesting microstructural changes in the extracellular matrix that could explain the resulting mechanical behavior of arteries with elastin degradation. PMID:24358135

Mechanical stretch modulates microRNA 21 expression, participating in proliferation and apoptosis in cultured human aortic smooth muscle cells.

Directory of Open Access Journals (Sweden)

Jian tao Song

Full Text Available OBJECTIVES: Stretch affects vascular smooth muscle cell proliferation and apoptosis, and several responsible genes have been proposed. We tested whether the expression of microRNA 21 (miR-21 is modulated by stretch and is involved in stretch-induced proliferation and apoptosis of human aortic smooth muscle cells (HASMCs. METHODS AND RESULTS: RT-PCR revealed that elevated stretch (16% elongation, 1 Hz increased miR-21 expression in cultured HASMCs, and moderate stretch (10% elongation, 1 Hz decreased the expression. BrdU incorporation assay and cell counting showed miR-21 involved in the proliferation of HASMCs mediated by stretch, likely by regulating the expression of p27 and phosphorylated retinoblastoma protein (p-Rb. FACS analysis revealed that the complex of miR-21 and programmed cell death protein 4 (PDCD4 participated in regulating apoptosis with stretch. Stretch increased the expression of primary miR-21 and pre-miR-21 in HASMCs. Electrophoretic mobility shift assay (EMSA demonstrated that stretch increased NF-κB and AP-1 activities in HASMCs, and blockade of AP-1 activity by c-jun siRNA significantly suppressed stretch-induced miR-21 expression. CONCLUSIONS: Cyclic stretch modulates miR-21 expression in cultured HASMCs, and miR-21 plays important roles in regulating proliferation and apoptosis mediated by stretch. Stretch upregulates miR-21 expression at least in part at the transcription level and AP-1 is essential for stretch-induced miR-21 expression.

Parameters Controlling Dimensional Accuracy of Aluminum Extrusions Formed in Stretch Bending

International Nuclear Information System (INIS)

Baringbing, Henry Ako; Welo, Torgeir

2007-01-01

For stretch formed components used in the automotive industry, such as bumper beams, it is of primary importance to control parameters affecting dimensional accuracy. The variations in geometry and mechanical properties induced in extrusion and stretch forming lead to subsequent dimensional inaccuracy of the final product. In this work, tensile and compression samples were taken at three different positions along AA7108W extruded profiles in order to determine material parameters for a constitutive model particularly suited for strong texture materials. In addition, geometry were measured and analyzed statistically in order to study its impact on local cross sectional distortions (sagging) and springback in stretch bending of a bumper beam. These full scale experiments were combined with analytical and numerical simulations to quantify the impact of each basic parameter on product quality. It is concluded that this methodology provides a means to systematically control the product quality by focusing on reducing the acceptance limits of the main parameters controlling basic mechanisms in stretch forming. Despite the assumptions and simplifications made in order to make the analytical expressions solvable, the approach has proven its capability in establishing accurate closed-form expressions including the main influential parameters

Mediators of Yoga and Stretching for Chronic Low Back Pain

Directory of Open Access Journals (Sweden)

Karen J. Sherman

2013-01-01

Full Text Available Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week, cognitive (fear avoidance, body awareness, and self-efficacy, affective (psychological distress, perceived stress, positive states of mind, and sleep, and physiological factors (cortisol, DHEA mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ. For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators. For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators. In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups, relaxation, increased awareness, and the benefits of breathing (yoga, benefits of regular practice (stretching. Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

Comparison between static stretching and the Pilates method on the flexibility of older women.

Science.gov (United States)

Oliveira, Laís Campos de; Oliveira, Raphael Gonçalves de; Pires-Oliveira, Deise Aparecida de Almeida

2016-10-01

Flexibility decreases with advancing age and some forms of exercise, such as static stretching and Pilates, can contribute to the improvement of this physical ability. To compare the effects of static stretching and Pilates on the flexibility of healthy older women, over the age of 60 years. Thirty-two volunteers were randomized into two groups (Static stretching or Pilates) to perform exercises for 60 min, twice a week, for three months. Evaluations to analyze the movements of the trunk (flexion and extension), hip flexion and plantar and dorsiflexion of the ankle were performed before and after the intervention, using a fleximeter. The static stretching exercises improved the trunk flexion and hip flexion movements, while the Pilates improved all evaluated movements. However, over time, the groups presented differences only for the trunk extension movement. For some body segments, Pilates may be more effective for improving flexibility in older women compared to static stretching. Copyright © 2016 Elsevier Ltd. All rights reserved.

Laboratory injection molder for the fabrication of polymeric porous poly-epsilon-caprolactone scaffolds for preliminary mesenchymal stem cells tissue engineering applications

KAUST Repository

Limongi, Tania; Lizzul, Lucia; Giugni, Andrea; Tirinato, Luca; Pagliari, Francesca; Tan, Hua; Das, Gobind; Moretti, Manola; Marini, Monica; Brusatin, Giovanna; Falqui, Andrea; Torre, Bruno; Di Benedetto, Cristiano; Di Fabrizio, Enzo M.

2016-01-01

with the poly-epsilon-caprolactone (PCL) granules using a screwed thermo regulated extruder, than the biocompatible scaffolds are fabricated through injection molding. The micro/nano structure of the samples and their different grade of porosity were

Design considerations and challenges for mechanical stretch bioreactors in tissue engineering.

Science.gov (United States)

Lei, Ying; Ferdous, Zannatul

2016-05-01

With the increase in average life expectancy and growing aging population, lack of functional grafts for replacement surgeries has become a severe problem. Engineered tissues are a promising alternative to this problem because they can mimic the physiological function of the native tissues and be cultured on demand. Cyclic stretch is important for developing many engineered tissues such as hearts, heart valves, muscles, and bones. Thus a variety of stretch bioreactors and corresponding scaffolds have been designed and tested to study the underlying mechanism of tissue formation and to optimize the mechanical conditions applied to the engineered tissues. In this review, we look at various designs of stretch bioreactors and common scaffolds and offer insights for future improvements in tissue engineering applications. First, we summarize the requirements and common configuration of stretch bioreactors. Next, we present the features of different actuating and motion transforming systems and their applications. Since most bioreactors must measure detailed distributions of loads and deformations on engineered tissues, techniques with high accuracy, precision, and frequency have been developed. We also cover the key points in designing culture chambers, nutrition exchanging systems, and regimens used for specific tissues. Since scaffolds are essential for providing biophysical microenvironments for residing cells, we discuss materials and technologies used in fabricating scaffolds to mimic anisotropic native tissues, including decellularized tissues, hydrogels, biocompatible polymers, electrospinning, and 3D bioprinting techniques. Finally, we present the potential future directions for improving stretch bioreactors and scaffolds. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:543-553, 2016. © 2016 American Institute of Chemical Engineers.

Reducing charging effects in scanning electron microscope images by Rayleigh contrast stretching method (RCS).

Science.gov (United States)

Wan Ismail, W Z; Sim, K S; Tso, C P; Ting, H Y

2011-01-01

To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts. Copyright © 2011 Wiley Periodicals, Inc.

Prolonged static stretching does not influence running economy despite changes in neuromuscular function.

Science.gov (United States)

Allison, Sarah J; Bailey, David M; Folland, Jonathan P

2008-12-01

The aim of this study was to examine the acute effects of prolonged static stretching (SS) on running economy. Ten male runners (VO2(peak) 60.1 +/- 7.3 ml x kg(-1) x min(-1)) performed 10 min of treadmill running at 70% VO2(peak) before and after SS and no stretching interventions. For the stretching intervention, each leg was stretched unilaterally for 40 s with each of eight different exercises and this was repeated three times. Respiratory gas exchange was measured throughout the running exercise with an automated gas analysis system. On a separate day, participants were tested for sit and reach range of motion, isometric strength and countermovement jump height before and after SS. The oxygen uptake, minute ventilation, energy expenditure, respiratory exchange ratio and heart rate responses to running were unaffected by the stretching intervention. This was despite a significant effect of SS on neuromuscular function (sit and reach range of motion, +2.7 +/- 0.6 cm; isometric strength, -5.6% +/- 3.4%; countermovement jump height -5.5% +/- 3.4%; all P influence running economy despite changes in neuromuscular function.

Effect of carbon on interstitial ordering and magnetic properties of epsilon-Fe-2(N,C)(1-z)

Czech Academy of Sciences Publication Activity Database

Brink, B. K.; Stahl, K.; Christiansen, T. L.; Frandsen, C.; Hansen, M. F.; Beran, Přemysl; Somers, M. A. J.

2017-01-01

Roč. 694, FEB (2017), s. 282-291 ISSN 0925-8388 R&D Projects: GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : neutron diffraction * vibrating sample magnotometry * Epsilon iron nitride * thermal expansion * interstitial order Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.133, year: 2016

Identification of the Process of Dynamic Stretching of Threads in Warp Knitting Technology Part II: Experimental Identification of the Process of Stretching Threads, with Verification of Rheological Models

Directory of Open Access Journals (Sweden)

Prążyńska Aleksandra

2018-03-01

Full Text Available The study is a continuation of the first part of the publication, concerning the theoretical analysis of sensitivity of rheological models of dynamically stretched thread. This part presents the experimental research on the characteristics of stretching forces as a function of time, in the context of comparing the obtained results with theoretical data.

THUNDER Piezoelectric Actuators as a Method of Stretch-Tuning an Optical Fiber Grating

Science.gov (United States)

Allison, Sidney G.; Fox, Robert L.; Froggatt, Mark E.; Childers, Brooks A.

2000-01-01

A method of stretching optical fiber holds interest for measuring strain in smart structures where the physical displacement may be used to tune optical fiber lasers. A small, light weight, low power tunable fiber laser is ideal for demodulating strain in optical fiber Bragg gratings attached to smart structures such as the re-usable launch vehicle that is being developed by NASA. A method is presented for stretching optical fibers using the THUNDER piezoelectric actuators invented at NASA Langley Research Center. THUNDER actuators use a piezoelectric layer bonded to a metal backing to enable the actuators to produce displacements larger than the unbonded piezoelectric material. The shift in reflected optical wavelength resulting from stretching the fiber Bragg grating is presented. Means of adapting THUNDER actuators for stretching optical fibers is discussed, including ferrules, ferrule clamp blocks, and plastic hinges made with stereo lithography.

FUZZY BASED CONTRAST STRETCHING FOR MEDICAL IMAGE ENHANCEMENT

Directory of Open Access Journals (Sweden)

T.C. Raja Kumar

2011-07-01

Full Text Available Contrast Stretching is an important part in medical image processing applications. Contrast is the difference between two adjacent pixels. Fuzzy statistical values are analyzed and better results are produced in the spatial domain of the input image. The histogram mapping produces the resultant image with less impulsive noise and smooth nature. The probabilities of gray values are generated and the fuzzy set is determined from the position of the input image pixel. The result indicates the good performance of the proposed fuzzy based stretching. The inverse transform of the real values are mapped with the input image to generate the fuzzy statistics. This approach gives a flexible image enhancement for medical images in the presence of noises.

Centrifugal stretching along the ground state band of 168Hf

International Nuclear Information System (INIS)

Costin, A.; Pietralla, N.; Reese, M.; Moeller, O.; Ai, H.; Casten, R. F.; Heinz, A.; McCutchan, E. A.; Meyer, D. A.; Qian, J.; Werner, V.; Dusling, K.; Fitzpatrick, C. R.; Guerdal, G.; Petkov, P.; Rainovski, G.

2009-01-01

The lifetimes of the J π =4 + , 6 + , 8 + , and 10 + levels along the ground state band in 168 Hf were measured by means of the recoil distance Doppler shift (RDDS) method using the New Yale Plunger Device (NYPD) and the SPEEDY detection array at Wright Nuclear Structure Laboratory of Yale University. Excited states in 168 Hf were populated using the 124 Sn( 48 Ti,4n) fusion evaporation reaction. The new lifetime values are sufficiently precise to clearly prove the increase of quadrupole deformation as a function of angular momentum in the deformed nucleus 168 Hf. The data agree with the predictions from the geometrical confined β-soft (CBS) rotor model that involves centrifugal stretching in a soft potential

Mechanical properties of Bi,Pb(2223) single filaments and I sub c (epsilon) behaviour in longitudinally strained tapes

CERN Document Server

Passerini, R; Seeber, B; Flükiger, R

2002-01-01

The Young's modulus and fracture stress of isolated Bi,Pb(2223) filaments were deduced from three-point bending tests performed at different stages of the tapes preparation. These results were introduced in the model describing the evolution of critical current of tapes submitted to a longitudinal strain in view to predict their irreversible strain limit epsilon sub i sub r sub r. These calculated irreversible strain limits were compared to measured values, taken from a set of tapes made with different filling factors and composite matrices. This experiment shows that the predicted irreversible strain limits correspond to the measured ones. Presenting the I sub c behaviour of highly stressed tapes in a magnetic field, we discuss the evolution of the ratio I sup s sup t sup r sup o sup n sup g sub c sub 0 /I sub c sub 0 versus strain. This value, representative of the fraction of the critical current attributed to strongly connected grains, increases significantly during the crack formation regime at epsilon >...

Micropatterning stretched and aligned DNA for sequence-specific nanolithography

Science.gov (United States)

Petit, Cecilia Anna Paulette

Techniques for fabricating nanostructured materials can be categorized as either "top-down" or "bottom-up". Top-down techniques use lithography and contact printing to create patterned surfaces and microfluidic channels that can corral and organize nanoscale structures, such as molecules and nanorods in contrast; bottom-up techniques use self-assembly or molecular recognition to direct the organization of materials. A central goal in nanotechnology is the integration of bottom-up and top-down assembly strategies for materials development, device design; and process integration. With this goal in mind, we have developed strategies that will allow this integration by using DNA as a template for nanofabrication; two top-down approaches allow the placement of these templates, while the bottom-up technique uses the specific sequence of bases to pattern materials along each strand of DNA. Our first top-down approach, termed combing of molecules in microchannels (COMMIC), produces microscopic patterns of stretched and aligned molecules of DNA on surfaces. This process consists of passing an air-water interface over end adsorbed molecules inside microfabricated channels. The geometry of the microchannel directs the placement of the DNA molecules, while the geometry of the airwater interface directs the local orientation and curvature of the molecules. We developed another top-down strategy for creating micropatterns of stretched and aligned DNA using surface chemistry. Because DNA stretching occurs on hydrophobic surfaces, this technique uses photolithography to pattern vinyl-terminated silanes on glass When these surface-, are immersed in DNA solution, molecules adhere preferentially to the silanized areas. This approach has also proven useful in patterning protein for cell adhesion studies. Finally, we describe the use of these stretched and aligned molecules of DNA as templates for the subsequent bottom-up construction of hetero-structures through hybridization

′Sure closure′-skin stretching system, our clinical experience

Directory of Open Access Journals (Sweden)

Subramania K

2005-01-01

Full Text Available Objective: In clinical practice of reconstructive surgery one of the problems one routinely comes across is skin and soft tissue defects, which require coverage. Coverage of such wounds requires primary/secondary closure, skin grafting or flaps. The objective of our clinical series was to assess the efficacy of sure closure skin stretching system for closure of defects which otherwise would have required major flap cover or skin grafting. Methods: Our series included five patients with different causes and types of wound defects namely: 1. Post-traumatic soft tissue defect on dorsum of hand. 2. Post fasciotomy wound on leg (anterolateral aspect. 3. Abdominal wound dehiscence following surgery for enterocutaneous fistula. 4. Leg soft tissue defect following dehiscence of fasciocutaneous flap. 5. Secondary defect following harvesting a lateral arm/forearm free flap. The device was applied to skin edges after preparing the wound under local anesthesia and the skin edges were brought together by turning the skin-stretching knob. After adequate approximation of the edges of the wound it was sutured by conventional suturing techniques. Results: All the wounds could be successfully closed using the skin stretching system in our series. The time taken for the closure ranged from 2 to 48 h. Conclusions: Sure closure skin stretching system is an effective device for closing some of the skin defects which otherwise would have required skin flaps or grafts. In all the patients wound closure could be achieved by this method and was carried out under local anesthesia. Use of this technique is simple and helps to reduce the morbidity and cost of treatment by allowing the reconstructive surgeon to avoid using major flaps or grafts.

Stretching of Active Muscle Elicits Chronic Changes in Multiple Strain Risk Factors.

Science.gov (United States)

Kay, Anthony David; Richmond, Dominic; Talbot, Chris; Mina, Minas; Baross, Anthony William; Blazevich, Anthony John

2016-07-01

The muscle stretch intensity imposed during "flexibility" training influences the magnitude of joint range of motion (ROM) adaptation. Thus, stretching while the muscle is voluntarily activated was hypothesized to provide a greater stimulus than passive stretching. The effect of a 6-wk program of stretch imposed on an isometrically contracting muscle (i.e., qualitatively similar to isokinetic eccentric training) on muscle-tendon mechanics was therefore studied in 13 healthy human volunteers. Before and after the training program, dorsiflexion ROM, passive joint moment, and maximal isometric plantarflexor moment were recorded on an isokinetic dynamometer. Simultaneous real-time motion analysis and ultrasound imaging recorded gastrocnemius medialis muscle and Achilles tendon elongation. Training was performed twice weekly and consisted of five sets of 12 maximal isokinetic eccentric contractions at 10°·s. Significant increases (P tendon stiffness) was detected (-1.5%, P > 0.05), a significant increase in tendon stiffness (31.2%, P tendon stiffness simultaneous with significant increases in tendon stiffness and decreases in passive muscle stiffness indicates that tissue-specific effects were elicited.

Evaluating airline energy efficiency: An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure

International Nuclear Information System (INIS)

Xu, Xin; Cui, Qiang

2017-01-01

This paper focuses on evaluating airline energy efficiency, which is firstly divided into four stages: Operations Stage, Fleet Maintenance Stage, Services Stage and Sales Stage. The new four-stage network structure of airline energy efficiency is a modification of existing models. A new approach, integrated with Network Epsilon-based Measure and Network Slacks-based Measure, is applied to assess the overall energy efficiency and divisional efficiency of 19 international airlines from 2008 to 2014. The influencing factors of airline energy efficiency are analyzed through the regression analysis. The results indicate the followings: 1. The integrated model can identify the benchmarking airlines in the overall system and stages. 2. Most airlines' energy efficiencies keep steady during the period, except for some sharply fluctuations. The efficiency decreases mainly centralized in the year 2008–2011, affected by the financial crisis in the USA. 3. The average age of fleet is positively correlated with the overall energy efficiency, and each divisional efficiency has different significant influencing factors. - Highlights: • An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure is developed. • 19 airlines' energy efficiencies are evaluated. • Garuda Indonesia has the highest overall energy efficiency.

The R + var-epsilon R2 cosmology

International Nuclear Information System (INIS)

Morris, M.S.

1988-01-01

This thesis presents the study of a model cosmology based on the R + var-epsilon R 2 gravitational Lagrangian. It may be roughly divided into two distinct parts. First, the classical inflationary scenario is developed. Then, the formalism of quantum cosmology is employed to determined initial conditions for the classical model. In the work on the classical model, the evolution equations for an isotropic and homogeneous universe are solved to exhibit both early-time inflation and a smooth transition to subsequent radiation-dominated behavior. Then perturbations on this isotropic background are evolved through the model to provide constraints on the model parameters from the observational limits on anisotropy today. In the work on the wave function, the two boundary conditions of Vilenkin and Hartle and Hawking are compared. The wave functions obtained are restricted to the initial edge of classical Lorentzian inflationary trajectories as distributions over initial conditions for the classical inflationary model. It is found that Vilenkin's wave function prefers the universe to undergo a great deal of inflation, whereas Hartle and Hawking's wave function prefers the universe to undergo little inflation. Finally, both boundary conditions are shown to require the inhomogeneous perturbative modes start out in their ground states

Pre-Stretched Low Equivalent Weight PFSA Membranes with Improved Fuel Cell Performance

DEFF Research Database (Denmark)

Zhang, Wenjing (Angela); Wycisk, Ryszard; Kish, Daniel L.

2014-01-01

for the morphological changes to be permanent. For 825 EW PFSA, stretching increased the polymer crystallinity by 22.5%, with a reduction in methanol permeability and a small increase in proton conductivity. In direct methanol fuel cell tests at 60◦C with 1.0 M methanol, the power density at 0.4 V with a DR = 4...... stretched 825 EW membrane (72 mW/cm2) was considerably greater than that obtained with a solution-cast membrane (28 mW/cm2) or with a commercial Nafion 117 membrane (55 mW/cm2). For 733 EW PFSA, stretching promoted the formation of ordered ionic domains leading to an increase in proton conductivity...

Exercise, especially combined stretching and strengthening exercise, reduces myofascial pain: a systematic review

Directory of Open Access Journals (Sweden)

Juliano Bergamaschine Mata Diz

2017-01-01

Full Text Available Question: Among people with myofascial pain, does exercise reduce the intensity of the pain and disability? Design: Systematic review of randomised and quasi-randomised controlled trials. Participants: People with myofascial pain of any duration. Intervention: Exercise versus minimal or no intervention and exercise versus other intervention. Outcome measures: Pain intensity and disability. Results: Eight studies involving 255 participants were included. Pooled estimates from six studies showed statistically significant effects of exercise when compared with minimal or no intervention (support and encouragement or no treatment on pain intensity at short-term follow-up. The weighted mean difference in pain intensity due to exercise was –1.2 points (95% CI –2.3 to –0.1 on a 0 to 10 scale. Pooled estimates from two studies showed a non-significant effect of exercise when compared with other interventions (electrotherapy or dry needling on pain intensity at short-term follow-up. The weighted mean difference in pain intensity due to exercise instead of other therapies was 0.4 points (95% CI –0.3 to 1.1 on a 0 to 10 scale. Individual studies reported no significant effects of exercise on disability compared with minimal intervention (–0.4, 95% CI –1.3 to 0.5 and other interventions (0.0, 95% CI –0.8 to 0.8 at short-term follow-up. Sensitivity analysis suggested that combining stretching and strengthening achieves greater short-term effects on pain intensity compared with minimal or no intervention (–2.3, 95% CI –4.1 to –0.5. Conclusion: Evidence from a limited number of trials indicates that exercise has positive small-to-moderate effects on pain intensity at short-term follow-up in people with myofascial pain. A combination of stretching and strengthening exercises seems to achieve greater effects. These estimates may change with future high-quality studies. [Mata Diz JB, de Souza JRLM, Leopoldino AAO, Oliveira VC (2016 Exercise

Development of Aluminum-Lithium 2195 Gores by the Stretch Forming Process

Science.gov (United States)

Volz, M. P.; Chen, P. S.; Gorti, S.; Salvail, P.

2014-01-01

Aluminum-Lithium alloy 2195 exhibits higher mechanical properties and lower density than aluminum alloy 2219, which is the current baseline material for Space Launch System (SLS) cryogenic tank components. Replacement of Al 2219 with Al-Li 2195 would result in substantial weight savings, as was the case when this replacement was made on the shuttle external tank. A key component of cryogenic tanks are the gores, which are welded together to make the rounded ends of the tanks. The required thicknesses of these gores depend on the specific SLS configuration and may exceed the current experience base in the manufacture of such gores by the stretch forming process. Here we describe the steps taken to enhance the formability of Al-Li 2195 by optimizing the heat treatment and stretch forming processes for gore thicknesses up to 0.75", which envelopes the maximum expected gore thicknesses for SLS tanks. An annealing treatment, developed at Marshall Space Flight Center, increased the forming range and strain hardening exponent of Al-Li 2195 plates. Using this annealing treatment, one 0.525" thick and two 0.75" thick gores were manufactured by the stretch forming process. The annealing treatment enabled the stretch forming of the largest ever cross sectional area (thickness x width) of an Al-Li 2195 plate achieved by the manufacturer. Mechanical testing of the gores showed greater than expected ultimate tensile strength, yield strength, modulus, and elongation values. The gores also exhibited acceptable fracture toughness at room and LN2 temperatures. All of the measured data indicate that the stretch formed gores have sufficient material properties to be used in flight domes.

Structure of modified [epsilon]-polylysine micelles and their application in improving cellular antioxidant activity of curcuminoids

Energy Technology Data Exchange (ETDEWEB)

Yu, Hailong; Li, Ji; Shi, Ke; Huang, Qingrong (Rutgers)

2015-10-15

The micelle structure of octenyl succinic anhydride modified {var_epsilon}-polylysine (M-EPL), an anti-microbial surfactant prepared from natural peptide {var_epsilon}-polylysine in aqueous solution has been studied using synchrotron small-angle X-ray scattering (SAXS). Our results revealed that M-EPLs formed spherical micelles with individual size of 24-26 {angstrom} in aqueous solution which could further aggregate to form a larger dimension with averaged radius of 268-308 {angstrom}. Furthermore, M-EPL micelle was able to encapsulate curcuminoids, a group of poorly-soluble bioactive compounds from turmeric with poor oral bioavailability, and improve their water solubility. Three loading methods, including solvent evaporation, dialysis, and high-speed homogenization were compared. The results indicated that the dialysis method generated the highest loading capacity and curcuminoids water solubility. The micelle encapsulation was confirmed as there were no free curcuminoid crystals detected in the differential scanning calorimetry analysis. It was also demonstrated that M-EPL encapsulation stabilized curcuminoids against hydrolysis at pH 7.4 and the encapsulated curcuminoids showed elevated cellular antioxidant activity compared with free curcuminoids. This work suggested that M-EPL could be used as new biopolymer micelles for delivering poorly soluble drugs/phytochemicals and improving their bioactivities.

Immobilization and therapeutic passive stretching generate thickening and increase the expression of laminin and dystrophin in skeletal muscle

International Nuclear Information System (INIS)

Cação-Benedini, L.O.; Ribeiro, P.G.; Prado, C.M.; Chesca, D.L.; Mattiello-Sverzut, A.C.

2014-01-01

Extracellular matrix and costamere proteins transmit the concentric, isometric, and eccentric forces produced by active muscle contraction. The expression of these proteins after application of passive tension stimuli to muscle remains unknown. This study investigated the expression of laminin and dystrophin in the soleus muscle of rats immobilized with the right ankle in plantar flexion for 10 days and subsequent remobilization, either by isolated free movement in a cage or associated with passive stretching for up to 10 days. The intensity of the macrophage response was also evaluated. One hundred and twenty-eight female Wistar rats were divided into 8 groups: free for 10 days; immobilized for 10 days; immobilized/free for 1, 3, or 10 days; or immobilized/stretched/free for 1, 3, or 10 days. After the experimental procedures, muscle tissue was processed for immunofluorescence (dystrophin/laminin/CD68) and Western blot analysis (dystrophin/laminin). Immobilization increased the expression of dystrophin and laminin but did not alter the number of macrophages in the muscle. In the stretched muscle groups, there was an increase in dystrophin and the number of macrophages after 3 days compared with the other groups; dystrophin showed a discontinuous labeling pattern, and laminin was found in the intracellular space. The amount of laminin was increased in the muscles treated by immobilization followed by free movement for 10 days. In the initial stages of postimmobilization (1 and 3 days), an exacerbated macrophage response and an increase of dystrophin suggested that the therapeutic stretching technique induced additional stress in the muscle fibers and costameres

Immobilization and therapeutic passive stretching generate thickening and increase the expression of laminin and dystrophin in skeletal muscle

Energy Technology Data Exchange (ETDEWEB)

Cação-Benedini, L.O.; Ribeiro, P.G. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Medicina e Reabilitação do Aparelho Locomotor, Departamento de Biomecânica, Ribeirão Preto, SP, Brasil, Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Prado, C.M.; Chesca, D.L. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Patologia, Ribeirão Preto, SP, Brasil, Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Mattiello-Sverzut, A.C. [Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Medicina e Reabilitação do Aparelho Locomotor, Departamento de Biomecânica, Ribeirão Preto, SP, Brasil, Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

2014-05-09

Extracellular matrix and costamere proteins transmit the concentric, isometric, and eccentric forces produced by active muscle contraction. The expression of these proteins after application of passive tension stimuli to muscle remains unknown. This study investigated the expression of laminin and dystrophin in the soleus muscle of rats immobilized with the right ankle in plantar flexion for 10 days and subsequent remobilization, either by isolated free movement in a cage or associated with passive stretching for up to 10 days. The intensity of the macrophage response was also evaluated. One hundred and twenty-eight female Wistar rats were divided into 8 groups: free for 10 days; immobilized for 10 days; immobilized/free for 1, 3, or 10 days; or immobilized/stretched/free for 1, 3, or 10 days. After the experimental procedures, muscle tissue was processed for immunofluorescence (dystrophin/laminin/CD68) and Western blot analysis (dystrophin/laminin). Immobilization increased the expression of dystrophin and laminin but did not alter the number of macrophages in the muscle. In the stretched muscle groups, there was an increase in dystrophin and the number of macrophages after 3 days compared with the other groups; dystrophin showed a discontinuous labeling pattern, and laminin was found in the intracellular space. The amount of laminin was increased in the muscles treated by immobilization followed by free movement for 10 days. In the initial stages of postimmobilization (1 and 3 days), an exacerbated macrophage response and an increase of dystrophin suggested that the therapeutic stretching technique induced additional stress in the muscle fibers and costameres.

FE-Analysis of Stretch-Blow Moulded Bottles Using an Integrative Process Simulation

Science.gov (United States)

Hopmann, C.; Michaeli, W.; Rasche, S.

2011-05-01

The two-stage stretch-blow moulding process has been established for the large scale production of high quality PET containers with excellent mechanical and optical properties. The total production costs of a bottle are significantly caused by the material costs. Due to this dominant share of the bottle material, the PET industry is interested in reducing the total production costs by an optimised material efficiency. However, a reduced material inventory means decreasing wall thicknesses and therewith a reduction of the bottle properties (e.g. mechanical properties, barrier properties). Therefore, there is often a trade-off between a minimal bottle weight and adequate properties of the bottle. In order to achieve the objectives Computer Aided Engineering (CAE) techniques can assist the designer of new stretch-blow moulded containers. Hence, tools such as the process simulation and the structural analysis have become important in the blow moulding sector. The Institute of Plastics Processing (IKV) at RWTH Aachen University, Germany, has developed an integrative three-dimensional process simulation which models the complete path of a preform through a stretch-blow moulding machine. At first, the reheating of the preform is calculated by a thermal simulation. Afterwards, the inflation of the preform to a bottle is calculated by finite element analysis (FEA). The results of this step are e.g. the local wall thickness distribution and the local biaxial stretch ratios. Not only the material distribution but also the material properties that result from the deformation history of the polymer have significant influence on the bottle properties. Therefore, a correlation between the material properties and stretch ratios is considered in an integrative simulation approach developed at IKV. The results of the process simulation (wall thickness, stretch ratios) are transferred to a further simulation program and mapped on the bottles FE mesh. This approach allows a local

Optical stretching on chip with acoustophoretic prefocusing

DEFF Research Database (Denmark)

Khoury Arvelo, Maria; Laub Busk, L.; Bruus, Henrik

2012-01-01

in the microchannel. Trapping and manipulation is demonstrated for dielectric beads. In addition, we show trapping, manipulation and stretching of red blood cells and vesicles, whereby we extract the elastic properties of these objects. Our design points towards the construction of a low-cost, high-throughput lab...

Comparison electrical stimulation and passive stretching for blood glucose control type 2 diabetes mellitus patients

Science.gov (United States)

Arsianti, Rika Wahyuni; Parman, Dewy Haryanti; Lesmana, Hendy

2018-04-01

Physical exercise is one of the cornerstones for management and treatment type 2 diabetes mellitus. But not all people are able to perform physical exercise because of their physical limitation condition. The strategy for those people in this study is electrical stimulation and passive stretching. The aim of this study is to find out the effect of electrical stimulation and passive stretching to lowering blood glucose level. 20 subjects is divided into electrical stimulation and passive stretching group. The provision of electrical stimulation on lower extremities muscles for 30 minutes for electrical stimulation group (N=10). And other underwent passive stretching for 30 minutes (N=10). The result shows that blood glucose level is decrease from 192.9 ± 10.7087 mg/dL to 165.3 ± 10.527 mg/dL for electrical stimulation intervention group while for the passive stretching group the blood glucose decrease from 153 ± 12.468 mg/dL to 136.1 ± 12.346 mg/dL. Both electrical stimulation and passive stretching are effective to lowering blood glucose level and can be proposed for those people restricted to perform exercise.

Mechanical stretch induces MMP-2 release and activation in lung endothelium: role of EMMPRIN.

Science.gov (United States)

Haseneen, Nadia A; Vaday, Gayle G; Zucker, Stanley; Foda, Hussein D

2003-03-01

High-volume mechanical ventilation leads to ventilator-induced lung injury. This type of lung injury is accompanied by an increased release and activation of matrix metalloproteinases (MMPs). To investigate the mechanism leading to the increased MMP release, we systematically studied the effect of mechanical stretch on human microvascular endothelial cells isolated from the lung. We exposed cells grown on collagen 1 BioFlex plates to sinusoidal cyclic stretch at 0.5 Hz using the Flexercell system with 17-18% elongation of cells. After 4 days of cell stretching, conditioned media and cell lysate were collected and analyzed by gelatin, casein, and reverse zymograms as well as Western blotting. RT-PCR of mRNA extracted from stretched cells was performed. Our results show that 1) cyclic stretch led to increased release and activation of MMP-2 and MMP-1; 2) the activation of MMP-2 was accompanied by an increase in membrane type-1 MMP (MT1-MMP) and inhibited by a hydroxamic acid-derived inhibitor of MMPs (Prinomastat, AG3340); and 3) the MMP-2 release and activation were preceded by an increase in production of extracellular MMP inducer (EMMPRIN). These results suggest that cyclic mechanical stretch leads to MMP-2 activation through an MT1-MMP mechanism. EMMPRIN may play an important role in the release and activation of MMPs during lung injury.

Self-induced stretch syncope of adolescence: a video-EEG documentation.

Science.gov (United States)

Mazzuca, Michel; Thomas, Pierre

2007-12-01

We present the first video-EEG documentation, with ECG and EMG features, of stretch syncope of adolescence in a young, healthy 16-year-old boy. Stretch syncope of adolescence is a rarely reported, benign cause of fainting in young patients, which can be confused with epileptic seizures. In our patient, syncopes were self-induced to avoid school. Dynamic transcranial Doppler showed evidence of blood flow decrease in both posterior cerebral arteries mimicking effects of a Valsalva manoeuvre. Dynamic angiogram of the vertebral arteries was normal. Hypotheses concerning the physiopathology are discussed. [Published with video sequences].

Stretch sensors for human body motion

Science.gov (United States)

O'Brien, Ben; Gisby, Todd; Anderson, Iain A.

2014-03-01

Sensing motion of the human body is a difficult task. From an engineers' perspective people are soft highly mobile objects that move in and out of complex environments. As well as the technical challenge of sensing, concepts such as comfort, social intrusion, usability, and aesthetics are paramount in determining whether someone will adopt a sensing solution or not. At the same time the demands for human body motion sensing are growing fast. Athletes want feedback on posture and technique, consumers need new ways to interact with augmented reality devices, and healthcare providers wish to track recovery of a patient. Dielectric elastomer stretch sensors are ideal for bridging this gap. They are soft, flexible, and precise. They are low power, lightweight, and can be easily mounted on the body or embedded into clothing. From a commercialisation point of view stretch sensing is easier than actuation or generation - such sensors can be low voltage and integrated with conventional microelectronics. This paper takes a birds-eye view of the use of these sensors to measure human body motion. A holistic description of sensor operation and guidelines for sensor design will be presented to help technologists and developers in the space.

Twist-stretch profiles of DNA chains

Science.gov (United States)

Zoli, Marco

2017-06-01

Helical molecules change their twist number under the effect of a mechanical load. We study the twist-stretch relation for a set of short DNA molecules modeled by a mesoscopic Hamiltonian. Finite temperature path integral techniques are applied to generate a large ensemble of possible configurations for the base pairs of the sequence. The model also accounts for the bending and twisting fluctuations between adjacent base pairs along the molecules stack. Simulating a broad range of twisting conformation, we compute the helix structural parameters by averaging over the ensemble of base pairs configurations. The method selects, for any applied force, the average twist angle which minimizes the molecule’s free energy. It is found that the chains generally over-twist under an applied stretching and the over-twisting is physically associated to the contraction of the average helix diameter, i.e. to the damping of the base pair fluctuations. Instead, assuming that the maximum amplitude of the bending fluctuations may decrease against the external load, the DNA molecule first over-twists for weak applied forces and then untwists above a characteristic force value. Our results are discussed in relation to available experimental information albeit for kilo-base long molecules.

Mechanical stretch augments insulin-induced vascular smooth muscle cell proliferation by insulin-like growth factor-1 receptor

Energy Technology Data Exchange (ETDEWEB)

Liu, Gang [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang (China); Hitomi, Hirofumi, E-mail: hitomi@kms.ac.jp [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Hosomi, Naohisa [Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa (Japan); Lei, Bai; Nakano, Daisuke [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Deguchi, Kazushi; Mori, Hirohito; Masaki, Tsutomu [Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa (Japan); Ma, Hong [Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang (China); Griendling, Kathy K. [Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, GA (United States); Nishiyama, Akira [Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa (Japan)

2011-10-15

Insulin resistance and hypertension have been implicated in the pathogenesis of cardiovascular disease; however, little is known about the roles of insulin and mechanical force in vascular smooth muscle cell (VSMC) remodeling. We investigated the contribution of mechanical stretch to insulin-induced VSMC proliferation. Thymidine incorporation was stimulated by insulin in stretched VSMCs, but not in un-stretched VSMCs. Insulin increased 2-deoxy-glucose incorporation in both stretched and un-stretched VSMCs. Mechanical stretch augmented insulin-induced extracellular signal-regulated kinase (ERK) and Akt phosphorylation. Inhibitors of epidermal growth factor (EGF) receptor tyrosine kinase and Src attenuated insulin-induced ERK and Akt phosphorylation, as well as thymidine incorporation, whereas 2-deoxy-glucose incorporation was not affected by these inhibitors. Moreover, stretch augmented insulin-like growth factor (IGF)-1 receptor expression, although it did not alter the expression of insulin receptor and insulin receptor substrate-1. Insulin-induced ERK and Akt activation, and thymidine incorporation were inhibited by siRNA for the IGF-1 receptor. Mechanical stretch augments insulin-induced VSMC proliferation via upregulation of IGF-1 receptor, and downstream Src/EGF receptor-mediated ERK and Akt activation. Similar to in vitro experiment, IGF-1 receptor expression was also augmented in hypertensive rats. These results provide a basis for clarifying the molecular mechanisms of vascular remodeling in hypertensive patients with hyperinsulinemia. -- Highlights: {yields} Mechanical stretch augments insulin-induced VSMC proliferation via IGF-1 receptor. {yields} Src/EGFR-mediated ERK and Akt phosphorylation are augmented in stretched VSMCs. {yields} Similar to in vitro experiment, IGF-1 receptor is increased in hypertensive rats. {yields} Results provide possible mechanisms of vascular remodeling in hypertension with DM.

COMPARATIVE EFFECT OF STATIC AND DYNAMIC STRETCHING EXERCISE TO IMPROVE FLEXIBILITY OF HAMSTRING MUSCLES AMONG NON ATHLETES

Directory of Open Access Journals (Sweden)

Jibi Paul

2014-10-01

Full Text Available Background: Stretching exercises have been routinely used in persons with hamstring tightness and athletes to increase flexibility of muscle and to reduce joint injuries. Many studies have reported effect of static and dynamic stretching on flexibility of this muscle. Finding the best method to improve flexibility of hamstring muscle is important for athletes and individuals to reduce their injuries. Objective of the study was to find out the effect of static stretching exercise and dynamic stretching exercise on flexibility of hamstring muscle and also to compare the effect of static and dynamic stretching exercise on flexibility of hamstring muscle. Methods: This was a comparative experimental study with seventy four female healthy subjects from physiotherapy department of KPJ Healthcare University College, Malaysia. Convenient sampling method used to select the samples. The subjects were selected by inclusion criteria and randomly divided equally in to two with 37 subjects in each group. Static stretching exercise and dynamic stretching exercise were given as intervention program for four weeks respectively for experimental and control group. Pre and post data of restricted range of movement for knee extension was measured using goniometry and documented separately for both group. Result: In experimental and control group, pre-post statistical analysis found significant effect in increase of hamstring flexibility with P<0.0001, for right and left side. Comparative study between experimental and control group found that static stretching exercise have significant effect in increase of hamstring flexibility for right and left side with P<0.04. Conclusion: This study concluded that static stretching exercise is more effective to improve hamstring flexibility compared to dynamic stretching exercise.

Bending and stretching of plates

CERN Document Server

Mansfield, E H; Hemp, W S

1964-01-01

The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

Modification of permeability of frog perineurium to [14C]-sucrose by stretch and hypertonicity

International Nuclear Information System (INIS)

Weerasuriya, A.; Rapoport, S.I.; Taylor, R.E.

1979-01-01

An in vitro method has been developed to determine quantitatively the permeability of the perineurium to radiotracers at room temperature. The permeability to [ 14 C]sucrose of the isolated perineurium of the sciatic nerve of the frog, Rana pipiens, was measured at rest length, when the perineurium was stretched and after the perineurium had been subjected to hypertonic treatment. Mean permeability at rest length was calculated to be 5.6 +- 0.27 (S.E.M., n=45)x10 -7 cm/sec, and both stretch and hypertonic treatment increased the permeability. A 10% stretch increased permeability reversibly, whereas a 20% stretch or immersion of the perineurium in a hypertonic bath increased permeability irreversibly. Altered permeability under these conditions might be related to changes in the ultrastructure of tight junctions in the perineurium. (Auth.)

Radiolabelling of isopeptide N{sup {epsilon}}-({gamma}-glutamyl)-L-lysine by conjugation with N-succinimidyl-4-[{sup 18}F]fluorobenzoate

Energy Technology Data Exchange (ETDEWEB)

Wuest, F; Hultsch, C; Bergmann, R; Johannsen, B; Henle, T

2003-07-01

The isopeptide N{sup {epsilon}}-({gamma}-glutamyl)-L-lysine 4 was labelled with {sup 18}F via N-succinimidyl-4-[{sup 18}F]fluorobenzoate ([{sup 18}F]SFB). A modified approach for the convenient synthesis of [{sup 18}F]SFB was used, and [{sup 18}F]SFB could be obtained in decay-corrected radiochemical yields of 44-53% (n=20) and radiochemical purity >95% within 40 min after EOB. For labelling N{sup {epsilon}}-({gamma}-glutamyl)-L-lysine with [{sup 18}F]SFB the effects of isopeptide concentration, temperature, and pH were studied to determine the optimum reaction conditions. The coupling reaction was shown to be temperature and pH independent while being strongly affected by the isopeptide concentration. Using the optimized labelling conditions, in a typical experiment 1.3 GBq of [{sup 18}F]SFB could be converted into 447 MBq (46%, decay-corrected) of [{sup 18}F]fluorobenzoylated isopeptide within 45 min, including HPLC purification.

Simulation of stretch forming with intermediate heat treatments of aircraft skins - A physically based modeling approach

NARCIS (Netherlands)

Kurukuri, S.; Miroux, Alexis; Wisselink, H.H.; van den Boogaard, Antonius H.

2011-01-01

In the aerospace industry stretch forming is often used to produce skin parts. During stretch forming a sheet is clamped at two sides and stretched over a die, such that the sheet gets the shape of the die. However for complex shapes it is necessary to use expensive intermediate heat-treatments in

Muscular and stato-kinetic functions rehabilitation by means of subaquatic stretching (hydrostretching

Directory of Open Access Journals (Sweden)

Zoltàn Pàsztay

2008-12-01

Full Text Available Stretching is a physical therapeutical way for maintaining the standard parameters of the body functions from a tender to anadvanced age. The most important parameter that is influenced by the different techniques of stretching, especially byhydrostretching, is flexibility. This article presents the technique and the effects of hydrostretching on human body (onmuscular balance, strength, muscular metabolism and circulation.

Experimental study on the deformation of erythrocytes under optically trapping and stretching

International Nuclear Information System (INIS)

Liu, Y.P.; Li Chuan; Lai, A.C.K.

2006-01-01

The mechanical behavior of erythrocytes is studied experimentally and numerically. In the experiment, prepared silica microbeads are attached to the surface of spherically swollen erythrocytes (red blood cells, RBCs) at room temperature (25 deg. C). The cells are then stretched by single laser beam via the microbeads. The relation of deformation and stretching force is quantitatively assessed by the image processing of digital pictures. Meanwhile, a physical model for an axisymmetric cell is introduced to study its deformation by different level of stretching force. By comparing the experimental and numerical data, stiffness of the cell membrane can be determined and the optimal values are found to agree with other studies by different techniques such as micropipette aspiration or high frequency electric field

Anomalies in the coil-stretch transition of flexible polymers

Science.gov (United States)

Ghosal, Aishani; Cherayil, Binny J.

2018-03-01

The flow-induced coil-stretch transition of high molecular weight polymers has generally been held to be of first order. But evidence of significant slowing down in the rate at which the polymers relax to equilibrium in the vicinity of the transition suggests that the thermodynamic character of the transition may be less clear-cut. The above slowing down effect is actually characteristic of a second-order transition, and it points to the existence of a broad spectrum of conformational states in the transition region, analogous to the existence of fluctuations of all length scales at a critical point. In this paper, using a path integral approach based on a free-draining finitely extensible chain model, we calculate various polymer properties as a function of elongational flow as a way of exploring different statistical mechanical details of the coil-stretch transition. These properties include the molecular weight dependence of the flow-extension curve of the polymer, the distribution of its steady-state end-to-end distances, and the characteristic relaxation time τR of these distances. Among other findings, our calculations indicate that the coil-stretch transition is discontinuous in the N → ∞ limit, that the effective free energy of the chain is unimodal at all values of the flow, becoming broad and flat in the immediate vicinity of the transition, and that the ratio of τR to the Rouse relaxation time increases abruptly at the transition before eventually reaching a plateau value at large flow strengths. These aspects of the coil-stretch transition place it among a larger class of unconventional nominally first-order single chain transitions that include the adsorption transition of surface-tethered polymers and the escape transition of compressed polymers.

Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

Science.gov (United States)

Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

2014-03-01

The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

Hyperglycemia Augments the Adipogenic Transdifferentiation Potential of Tenocytes and Is Alleviated by Cyclic Mechanical Stretch.

Science.gov (United States)

Wu, Yu-Fu; Huang, Yu-Ting; Wang, Hsing-Kuo; Yao, Chung-Chen Jane; Sun, Jui-Sheng; Chao, Yuan-Hung

2017-12-28

Diabetes mellitus is associated with damage to tendons, which may result from cellular dysfunction in response to a hyperglycemic environment. Tenocytes express diminished levels of tendon-associated genes under hyperglycemic conditions. In contrast, mechanical stretch enhances tenogenic differentiation. However, whether hyperglycemia increases the non-tenogenic differentiation potential of tenocytes and whether this can be mitigated by mechanical stretch remains elusive. We explored the in vitro effects of high glucose and mechanical stretch on rat primary tenocytes. Specifically, non-tenogenic gene expression, adipogenic potential, cell migration rate, filamentous actin expression, and the activation of signaling pathways were analyzed in tenocytes treated with high glucose, followed by the presence or absence of mechanical stretch. We analyzed tenocyte phenotype in vivo by immunohistochemistry using an STZ (streptozotocin)-induced long-term diabetic mouse model. High glucose-treated tenocytes expressed higher levels of the adipogenic transcription factors PPAR γ and C/EBPs. PPARγ was also highly expressed in diabetic tendons. In addition, increased adipogenic differentiation and decreased cell migration induced by high glucose implicated a fibroblast-to-adipocyte phenotypic change. By applying mechanical stretch to tenocytes in high-glucose conditions, adipogenic differentiation was repressed, while cell motility was enhanced, and fibroblastic morphology and gene expression profiles were strengthened. In part, these effects resulted from a stretch-induced activation of ERK (extracellular signal-regulated kinases) and a concomitant inactivation of Akt. Our results show that mechanical stretch alleviates the augmented adipogenic transdifferentiation potential of high glucose-treated tenocytes and helps maintain their fibroblastic characteristics. The alterations induced by high glucose highlight possible pathological mechanisms for diabetic tendinopathy

Tail modeling in a stretched magnetosphere 1. Methods and transformations

International Nuclear Information System (INIS)

Stern, D.P.

1987-01-01

A new method is developed for representing the magnetospheric field B as a distorted dipole field. Because delxB = 0 must be maintained,such a distortion may be viewed as a transformation of the vector potential A. The simplest form is a one-dimensional ''stretch transformation'' along the x axis, a generalization of a method introduced by Voigt. The transformation is concisely represented by the ''stretch function'' f(x), which is also a convenient tool for representing features of the substorm cycle. Onedimensional stretch transformations are extended to spherical, cylindrical, and parabolic coordinates and then to arbitrary coordinates. It is next shown that distortion transformations can be viewed as mappings of field lines from one pattern to another: Euler potentials are used in the derivation, but the final result only requires knowledge of the field and not of the potentials. General transformations in Cartesian and arbitrary coordinates are then derived,and applications to field modeling, field line motion, MHD modeling, and incompressible fluid dynamics are considered. copyrightAmerican Geophysical Union 1987

Development of EPSILON. A gamma ray imaging system for the nuclear industry

International Nuclear Information System (INIS)

Durrant, P.T.

1999-06-01

In recent years, much effort has been focused on the need to characterise, stabilise, decontaminate and eventually decommission radioactively contaminated nuclear facilities. These tasks can be complex and hazardous and are often hampered by a lack of knowledge of the nature and distribution of the contamination. A gamma-ray imaging system, capable of remotely mapping a contaminated scene, could be a useful tool in many tasks related to the decommissioning of nuclear facilities. This thesis describes and discusses the design, development, commissioning and characterisation of EPSILON, a multipurpose gamma-ray imaging system designed to meet the needs of a range of applications in the nuclear industry. Following a review of the range of potential applications and a critical assessment of the imaging systems available at the time, a set of design criteria for a multi-purpose gamma-ray imaging system are identified. The design and development of an imaging system to meet these criteria is described in detail. Suitable image-formation techniques are discussed and a pinhole collimator selected as the most appropriate. Consideration is given to the use of a scintillator-photodiode array as the imager detection plane but this option is rejected in favour of a position-sensitive photomultiplier tube (PSPMT). The development of two data-acquisition systems is described and comparisons made between the performance of these two techniques. The factors affecting the performance and image quality of this pinhole imaging system are discussed and a prototype design presented for a well-shielded, high-sensitivity imager. Experimental results obtained with this prototype are presented. These results demonstrate a good angular resolution of 1.6 deg across a 12.8 deg FOV and a factor of 7 improvement in sensitivity over a comparable resolution, single-pixel scanning-system. The spectral resolution of this prototype imager did not meet the design criteria. A modified design is

Effect of halloysite nanotubes on the thermal degradation behaviour of poly(.epsilon.-caprolactone)/poly(lactic acid) microfibrillar composites

Czech Academy of Sciences Publication Activity Database

Luyt, A. S.; Kelnar, Ivan

2017-01-01

Roč. 60, July (2017), s. 166-172 ISSN 0142-9418 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:61389013 Keywords : poly(lactic acid) * poly(epsilon-caprolactone) * halloysite nanotubes Subject RIV: JI - Composite Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 2.464, year: 2016

Plasmonic Lithography Utilizing Epsilon Near Zero Hyperbolic Metamaterial.

Science.gov (United States)

Chen, Xi; Zhang, Cheng; Yang, Fan; Liang, Gaofeng; Li, Qiaochu; Guo, L Jay

2017-10-24

In this work, a special hyperbolic metamaterial (HMM) metamaterial is investigated for plasmonic lithography of period reduction patterns. It is a type II HMM (ϵ ∥ 0) whose tangential component of the permittivity ϵ ∥ is close to zero. Due to the high anisotropy of the type II epsilon-near-zero (ENZ) HMM, only one plasmonic mode can propagate horizontally with low loss in a waveguide system with ENZ HMM as its core. This work takes the advantage of a type II ENZ HMM composed of aluminum/aluminum oxide films and the associated unusual mode to expose a photoresist layer in a specially designed lithography system. Periodic patterns with a half pitch of 58.3 nm were achieved due to the interference of third-order diffracted light of the grating. The lines were 1/6 of the mask with a period of 700 nm and ∼1/7 of the wavelength of the incident light. Moreover, the theoretical analyses performed are widely applicable to structures made of different materials such as silver as well as systems working at deep ultraviolet wavelengths including 193, 248, and 365 nm.

Prediction of Ductile Failure in the Stretch-Forming of AA2024 Sheets

International Nuclear Information System (INIS)

Vallellano, C.; Guzman, C.; Garcia-Lomas, F. J.

2007-01-01

A number of ductile failure criteria are nowadays being used to predict the formability of aluminium alloy sheets. Generally speaking, integral criteria (e.g. those proposed by Cockcroft and Latham, Brozzo et al., Oyane et al Chaouadi et al., etc.) have been probed to work well when the principal strains are of opposite sign, i.e. in the left side of the Forming Limit Diagram (FLD). However, when tensile biaxial strains are present, as occurs in stretch-forming practice, their predictions are usually very poor and even non-conservatives. As an alternative, local criteria, such as the classical Tresca's and Bressan and Williams' criteria, have demonstrated a good capability to predict the failure in some automotive aluminum alloys under stretching. The present work analyses experimentally and numerically the failure in AA2024-T3 sheets subjected to biaxial stretching. A series of out-of-plane stretching tests have been simulated using ABAQUS. The experimental and the numerical FLD for different failure criteria are compared. The influence on the failure of the hydrostatic pressure and the normal stress to the fracture plane is also discussed

A Novel Stretch Sensor to Measure Venous Hemodynamics

Directory of Open Access Journals (Sweden)

Syrpailyne Wankhar

2018-07-01

Full Text Available Chronic venous insufficiency is a debilitating condition causing varicose veins and venous ulcers. The pathophysiology includes reflux and venous obstruction. The diagnosis is often made by clinical examination and confirmed by Venous Doppler studies. Plethysmography helps to quantitatively examine the reflux and diagnose the burden of deep venous pathology to better understand venous hemodynamics, which is not elicited by venous duplex examination alone. However, most of these tests are qualitative, expensive, and not easily available. In this paper, we demonstrate the potential use of a novel stretch sensor in the assessment of venous hemodynamics during different maneuvers by measuring the change in calf circumference. We designed the stretch sensor by using semiconductor strain gauges pasted onto a small metal bar to form a load cell. The elastic and Velcro material attached to the load cell form a belt. It converts the change in limb circumference to a proportional tension (force of distension when placed around the calf muscle. We recorded the change in limb circumference from arrays of stretch sensors by using an in-house data acquisition system. We calculated the venous volume (VV, venous filling index (VFI, ejection fraction (EF and residual venous volume (RVV on two normal subjects and on two patients to assess venous hemodynamics. The values (VV > 60 ml, VFI 60%, RVV 2ml/s, EF 35% in patients were comparable to those reported in the literature.

Acute effect of different time periods of passive static stretching on the hamstring flexibility.

Science.gov (United States)

Cini, Anelize; de Vasconcelos, Gabriela Souza; Lima, Claudia Silveira

2017-01-01

Several factors are associated with the presence of chronic low back pain; one of them is the flexibility of the hamstring muscles that influences the posture of the pelvic spine. Investigate the influence of two different time periods of passive static stretching on the flexibility of the hamstring. Forty-six physiotherapy students were divided into two groups performing stretching exercises: 30 s and 60 s duration. The collections consisted of: (1) pre-test: evaluation of the flexibility of the hip and knee, using a manual goniometer by means of the following tests: Straight Leg Raise Test (SLR), Passive Hip Flexion Test (PHFT) and Modified Knee Extension Test (MKET), (2) intervention: stretching with different runtimes, (3) post-test: reappraisal of flexibility, conducted immediately after the intervention. Significant difference was observed intra groups, group that did stretching exercises lasting 30 seconds (G30) (SLR p = 0.000. PHFT p = 0.003 and MKET p = 0.000) and group that did stretching exercises lasting 60 seconds (G60) (SLR p = 0.000. PHFT p = 0.001 and MKET p = 0.002). Comparing the groups, no significant difference was found (SLR p = 0.307; PHFT p = 0.904; MKET p = 0.132). Thus it can be inferred that 30 seconds are sufficient for increased flexibility of young women. Therefore the time-treatment sessions can be optimized. Only the acute effect of stretching was observed; further investigation of the long-term effect is required.

The computation of turbulent recirculating flow using curvilinear finite differences. Application of the k - epsilon model to the flow in dredged trenches

International Nuclear Information System (INIS)

Alfrink, B.J.

1981-08-01

The report treats the computation of turbulent recirculating flow in dredged trenches. The mathematical model consists of the full two-dimensional unsteady Reynolds equations, formulated in primitive variables. Turbulence closure is obtained by means of a two-equation (k - epsilon) model. The numerical technique is based on the use of curvilinear finite differences in space and of fractional steps in time. A procedure is proposed to apply the model for varying roughness circumstances. The value of the Von Karman constant can be determined from geometric information. Afterwards, only the c 1 -constant is adapted by means of a degenerated epsilon-equation. The report describes an extensive sensitivity study for the inlet conditions and the empirical constants. Ultimately, the results of the mathematical model are very satisfactory. Compared with laboratory experiments, the recirculation length is only underpredicted with 10%

Hemodynamic responses during and after multiple sets of stretching exercises performed with and without the Valsalva maneuver.

Science.gov (United States)

Lima, Tainah P; Farinatti, Paulo T V; Rubini, Ercole C; Silva, Elirez B; Monteiro, Walace D

2015-05-01

This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver. Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated by 48-hour intervals. Hemodynamic responses were measured by photoplethysmography pre-exercise, during the stretching sets, and post-exercise. The effects of stretching sets on systolic and diastolic blood pressure were cumulative until the fourth set in protocols performed with and without the Valsalva maneuver. The heart rate and rate pressure product increased in both protocols, but no additive effect was observed due to the number of sets. Hemodynamic responses were always higher when stretching was performed with the Valsalva maneuver, causing an additional elevation in the rate pressure product. Multiple sets of unilateral hip flexion stretching significantly increased blood pressure, heart rate, and rate pressure product values. A cumulative effect of the number of sets occurred only for systolic and diastolic blood pressure, at least in the initial sets of the stretching protocols. The performance of the Valsalva maneuver intensified all hemodynamic responses, which resulted in significant increases in cardiac work during stretching exercises.

Comparison between Steroid Injection and Stretching Exercise on the Scalene of Patients with Upper Extremity Paresthesia: Randomized Cross-Over Study.

Science.gov (United States)

Kim, Yong Wook; Yoon, Seo Yeon; Park, Yongbum; Chang, Won Hyuk; Lee, Sang Chul

2016-03-01

To compare the therapeutic effects on upper extremity paresthesia of intra-muscular steroid injections into the scalene muscle with those of stretching exercise only. Twenty patients with upper extremity paresthesia who met the criteria were recruited to participate in this single-blind, crossover study. Fourteen of 20 patients were female. The average age was 45.0 ± 10.5 years and duration of symptom was 12.2 ± 8.7 months. Each participant completed one injection and daily exercise program for 2 weeks. After randomization, half of all patients received ultrasound-guided injection of scalene muscles before exercise, while the other was invested for the other patients. After two weeks, there was a significant decrease of the visual analog scale score of treatment effect compared with baseline in both groups (6.90 to 2.85 after injection and 5.65 to 4.05 after stretching exercise, p50% reduction in post-treatment visual analog scale, was 18 of 20 (90.0%) after injection, compared to 5 of 20 (25.0%) after stretching exercise. There were no cases of unintended brachial plexus block after injection. Ultrasound-guided steroid injection or stretching exercise of scalene muscles led to reduced upper extremity paresthesia in patients who present with localized tenderness in the scalene muscle without electrodiagnostic test abnormalities, although injection treatment resulted in more improvements. The results suggest that symptoms relief might result from injection into the muscle alone not related to blockade of the brachial plexus.

Stretched flow of Carreau nanofluid with convective boundary ...

Indian Academy of Sciences (India)

journal of. January 2016 physics pp. 3–17. Stretched flow of Carreau nanofluid with ... fluid over a flat plate subjected to convective surface condition. ... the steady laminar boundary layer flow over a permeable plate with a convective boundary.

The passive hamstring stretch test: clinical evaluation.

Science.gov (United States)

Fisk, J W

1979-03-28

The passive hamstring stretch test is described. Using a modified goniometer it is shown that independent measurements taken by trained examiners approximate very closely to each other. This establishes the test as a valid objective measurement. The possible value of this test as a research tool in low back pain problems is discussed.

Studies of elements used in hertzian interferometry (millimetric waves). Measurement of the permittivity of a liquid dielectric; Etudes d'elements utilises en interferometrie hertzienne (ondes millimetriques). Mesure de la permittivite de dielectrique liquide

Energy Technology Data Exchange (ETDEWEB)

Dagai, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-12-01

Study of some elements used in EHF interferometry (bond of millimeter waves). This study is about design of the following elements: horns, horns associated with lens, power separators: -) Study of assemblies allowing measurements of complex dielectric constants of liquids. These devices are used in free propagation about wave lengths {<=} 2 mm; -) Studied devices: Interferometer for 2 separated waves and Michelson's type interferometer; -) 4 liquids have been used: {epsilon}'{sub r} Octane from -50 to 70 C (-58 to 158 F), {epsilon}'{sub r} and {epsilon}'' [Monochlorobenzene at 22,8 C (73 F), Mixture of octane with 10,8 per cent citral at 22 C (72 F) and Benzene at 21 C (70 F)]. -) Precision obtained about measurements: {delta}{epsilon}'/{epsilon}' de 1 a 2%, {delta}{epsilon}''/{epsilon}'' de 4 a 6%.(author) [French] Etudes d'elements utilises en interferometrie hertzienne fonctionnant en ondes millimetriques. Cette etude porte sur la realisation des elements suivants: cornets, cornets associes aux lentilles, separateurs de puissance. Etudes des montages permettant les mesures de la constante dielectrique complexe des corps liquides. Ces montages fonctionnent en propagation libre, sur des longueurs d'onde inferieures ou egales a 2 millimetres. Les montages etudies sont: interferometre a deux ondes separees et interferometre du type Michelson. De plus 4 liquides ont ete etudies: {epsilon}'{sub r} octane de -50 a 70 C, {epsilon}'{sub r} et {epsilon}'' [monochlorobenzene a 22,8 C et melange octane avec 10,8 pour cent citral a 22 C, Benzene a 21 C]. Les precisions obtenues sur les mesures sont: {delta}{epsilon}'/{epsilon}' de 1 a 2 pour cent, {delta}{epsilon}''/{epsilon}'' de 4 a 6 pour cent.

Alternative splicing and expression of the insulin-like growth factor (IGF-1) gene in osteoblasts under mechanical stretch

Institute of Scientific and Technical Information of China (English)

XIAN Chengyu; WANG Yuanliang; ZHANG Bingbing; TANG Liling; PAN Jun; LUO Yanfeng; JIANG Peng; LI Dajun

2006-01-01

Insulin-like growth factor 1 (IGF-1) promotes osteoblasts differentiation and bone formation,and its expression is induced by mechanical stretch,thus IGF-1 has been considered an effector molecule that links mechanical stimulation and local tissue responses. In this study, a mechanical stretching device was designed to apply physiological level static or cyclic stretching stimulation to osteoblasts.Different isoforms of IGF-1 mRNA were amplified by RT-PCR from the cells using respective primers and these amplified products were sequenced. An isoform of IGF-1 splicing product was found to be selectively produced by osteoblasts under stretching stimulation. This IGF-1 isoform had identical sequence with the mechano growth factor (MGF) which was originally identified in muscle cells. Regulations of the expression of the liver-type IGF (L.IGF-1) and MGF in osteoblasts under stretch stimulation were further studied using semi-quantitative RT-PCR.Stretch stimulation was found to promot the expression of IGF-1 (L.IGF-1 and MGF), and for both isoforms expression was more effectively stimulated by cyclic stretch than static stretch. MGF was detected only in osteoblasts subjected to mechanical stretch,suggesting MGF was a stretch sensitive growth factor.Expression of MGF peaked earlier than that of L.IGF-1, which was similar to their regulation in muscie and suggested similar roles of MGF and L.IGF-1in bone as in muscle cells. The functions of MGF and L.IGF-1 in osteoblasts shall be established by further experimental studies.

The mechanical properties of dry, electrospun fibrinogen fibers

Energy Technology Data Exchange (ETDEWEB)

Baker, Stephen; Sigley, Justin; Helms, Christine C. [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States); Stitzel, Joel [Department of Biomedical Engineering, Wake Forest University Health Sciences, Winston-Salem, NC, 27157 (United States); Berry, Joel; Bonin, Keith [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States); Guthold, Martin, E-mail: gutholdm@wfu.edu [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States)

2012-02-01

Due to their low immunogenicity, biodegradability and native cell-binding domains, fibrinogen fibers may be good candidates for tissue engineering scaffolds, drug delivery vehicles and other medical devices. We used a combined atomic force microscope (AFM)/optical microscope technique to study the mechanical properties of individual, electrospun fibrinogen fibers in dry, ambient conditions. The AFM was used to stretch individual fibers suspended over 13.5 {mu}m wide grooves in a transparent substrate. The optical microscope, located below the sample, was used to monitor the stretching process. Electrospun fibrinogen fibers (diameter, 30-200 nm) can stretch to 74% beyond their original length before rupturing at a stress of 2.1 GPa. They can stretch elastically up to 15% beyond their original length. Using incremental stress-strain curves the viscoelastic behavior of these fibers was determined. The total stretch modulus was 4.2 GPa while the relaxed elastic modulus was 3.7 GPa. When held at constant strain, fibrinogen fibers display stress relaxation with a fast and slow relaxation time of 1.2 s and 11 s. In comparison to native and electrospun collagen fibers, dry electrospun fibrinogen fibers are significantly more extensible and elastic. In comparison to wet electrospun fibrinogen fibers, dry fibers are about 1000 times stiffer. - Highlights: Black-Right-Pointing-Pointer Fabricated dry, electrospun, fibrinogen fibers; average diameter, D{sub avg.} = 95 nm. Black-Right-Pointing-Pointer Determined mechanical properties with combined atomic force/optical microscope. Black-Right-Pointing-Pointer Fibers are very extensible ({epsilon}{sub max} = 74%) and elastic ({epsilon}{sub elastic} = 15%). Black-Right-Pointing-Pointer Fiber total modulus, E{sub tot.} = 4.2 GPa; elastic modulus, E{sub el.} = 3.7 GPa. Black-Right-Pointing-Pointer Fiber stress relaxation times: {tau}{sub 1} = 1.2 s and {tau}{sub 2} = 11 s.

A study of extracellular matrix remodeling in aortic heart valves using a novel biaxial stretch bioreactor.

Science.gov (United States)

Lei, Ying; Masjedi, Shirin; Ferdous, Zannatul

2017-11-01

In aortic valves, biaxial cyclic stretch is known to modulate cell differentiation, extracellular matrix (ECM) synthesis and organization. We designed a novel bioreactor that can apply independent and precise stretch along radial and circumferential directions in a tissue culture environment. While this bioreactor can be used for either native or engineered tissues, this study determined matrix remodeling and strain distribution of aortic cusps after culturing under biaxial stretch for 14 days. The contents of collagen and glycosaminoglycans were determined using standard biochemical assays and compared with fresh controls. Strain fields in static cusps were more uniform than those in stretched cusps, which indicated degradation of the ECM fibers. The glycosaminoglycan content was significantly elevated in the static control as compared to fresh or stretched cusps, but no difference was observed in collagen content among the groups. The strain profile of freshly isolated fibrosa vs. ventricularis and left, right, and noncoronary cusps were also determined by Digital Image Correlation technique. Distinct strain patterns were observed under stretch on fibrosa and ventricularis sides and among the three cusps. This work highlights the critical role of the anisotropic ECM structure for proper functions of native aortic valves and the beneficial effects of biaxial stretch for maintenance of the native ECM structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

STRETCHING EXERCISES - EFFECT ON PASSIVE EXTENSIBILITY AND STIFFNESS IN SHORT HAMSTRINGS OF HEALTHY-SUBJECTS

NARCIS (Netherlands)

HALBERTSMA, JPK; GOEKEN, LNH

Passive muscle stretch tests are common practice in physical therapy and rehabilitation medicine. However, the effects of stretching exercises are not well known. With an instrumental straight-leg-raising set-up the extensibility, stiffness, and electromyographic activity of the hamstring muscles

Cyclic mechanical stretch contributes to network development of osteocyte-like cells with morphological change and autophagy promotion but without preferential cell alignment in rat.

Science.gov (United States)

Inaba, Nao; Kuroshima, Shinichiro; Uto, Yusuke; Sasaki, Muneteru; Sawase, Takashi

2017-09-01

Osteocytes play important roles in controlling bone quality as well as preferential alignment of biological apatite c -axis/collagen fibers. However, the relationship between osteocytes and mechanical stress remains unclear due to the difficulty of three-dimensional (3D) culture of osteocytes in vitro . The aim of this study was to investigate the effect of cyclic mechanical stretch on 3D-cultured osteocyte-like cells. Osteocyte-like cells were established using rat calvarial osteoblasts cultured in a 3D culture system. Cyclic mechanical stretch (8% amplitude at a rate of 2 cycles min -1 ) was applied for 24, 48 and 96 consecutive hours. Morphology, cell number and preferential cell alignment were evaluated. Apoptosis- and autophagy-related gene expression levels were measured using quantitative PCR. 3D-cultured osteoblasts became osteocyte-like cells that expressed osteocyte-specific genes such as Dmp1 , Cx43 , Sost , Fgf23 and RANKL , with morphological changes similar to osteocytes. Cell number was significantly decreased in a time-dependent manner under non-loaded conditions, whereas cyclic mechanical stretch significantly prevented decreased cell numbers with increased expression of anti-apoptosis-related genes. Moreover, cyclic mechanical stretch significantly decreased cell size and ellipticity with increased expression of autophagy-related genes, LC3b and atg7 . Interestingly, preferential cell alignment did not occur, irrespective of mechanical stretch. These findings suggest that an anti-apoptotic effect contributes to network development of osteocyte-like cells under loaded condition. Spherical change of osteocyte-like cells induced by mechanical stretch may be associated with autophagy upregulation. Preferential alignment of osteocytes induced by mechanical load in vivo may be partially predetermined before osteoblasts differentiate into osteocytes and embed into bone matrix.

Comparison of the effects of local cryotherapy and passive cross-body stretch on extensibility in subjects with posterior shoulder tightness.

Science.gov (United States)

Park, Kyue-Nam; Kwon, Oh-Yun; Weon, Jong-Hyuck; Choung, Sung-Dae; Kim, Si-Hyun

2014-01-01

The objective was to compare the immediate effects of local cryotherapy (LC) and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR) range of motion (ROM) greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group). Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA) using numerical rating scale, and the pressure pain threshold (PPT) at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort. Key PointsLocal cryotherapy (LC) decreased the

Calcineurin /NFAT activation-dependence of leptin synthesis and vascular growth in response to mechanical stretch

Directory of Open Access Journals (Sweden)

Nadia Soudani

2016-09-01

Full Text Available Background and Aims- Hypertension and obesity are important risk factors of cardiovascular disease. They are both associated with high leptin levels and have been shown to promote vascular hypertrophy, through the RhoA/ROCK and ERK1/2 phosphorylation. Calcineurin/NFAT activation also induces vascular hypertrophy by upregulating various genes. This study aimed to decipher whether a crosstalk exists between the RhoA/ROCK pathway, Ca+2/calcineurin/NFAT pathway, and ERK1/2 phosphorylation in the process of mechanical stretch-induced vascular smooth muscle cell (VSMC hypertrophy and leptin synthesis. Methods and Results- Rat portal vein (RPV organ culture was used to investigate the effect of mechanical stretch and exogenous leptin (3.1 nM on VSMC hypertrophy and leptin synthesis. Results showed that stretching the RPV significantly upregulated leptin secretion, mRNA and protein expression, which were inhibited by the calcium channel blocker nifedipine (10 μM, the selective calcineurin inhibitor FK506 (1 nM and the ERK1/2 inhibitor PD98059 (1 μM. The transcription inhibitor actinomycin D (0.1M and the translation inhibitor cycloheximide (1 mM significantly decreased stretch-induced leptin protein expression. Mechanical stretch or leptin caused an increase in wet weight changes and protein synthesis, considered as hypertrophic markers, while they were inhibited by FK506 (0.1 nM; 1 nM. In addition, stretch or exogenous leptin significantly increased calcineurin activity and MCIP1 expression whereas leptin induced NFAT nuclear translocation in VSMCs. Moreover, in response to stretch or exogenous leptin, the Rho inhibitor C3 exoenzyme (30 ng/mL, the ROCK inhibitor Y-27632 (10 μM, and the actin depolymerization agents Latrunculin B (50 nM and cytochalasin D (1 μM reduced calcineurin activation and NFAT nuclear translocation. ERK1/2 phosphorylation was inhibited by FK506 and C3. Conclusions- Mechanical stretch-induced VSMC hypertrophy and leptin

A unique airborne observation. [Martian atmospheric temperature and abundances from occultation of Epsilon Geminorum

Science.gov (United States)

Elliot, J. L.; Dunham, E.; Church, C.

1976-01-01

The occultation of 3rd magnitude Epsilon Geminorum by Mars was observed using a 36-inch telescope equipped with a photoelectric photometer at the bent Cassegrain focus, carried aboard the Kuiper Airborne Observatory at altitudes up to 45,000 feet. Scintillation from the earth's atmosphere was greatly reduced in comparison with ground observations. The observations clearly show the central flash, caused by the symmetrical refraction of light by the atmosphere of Mars. The data are being analyzed to obtain temperature profiles and to assess the relative abundance of argon and carbon dioxide in the atmosphere of the planet.

Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties.

Science.gov (United States)

Konrad, A; Stafilidis, S; Tilp, M

2017-10-01

The purpose of this study was to investigate the influence of a single static, ballistic, or proprioceptive neuromuscular facilitation (PNF) stretching exercise on the various muscle-tendon parameters of the lower leg and to detect possible differences in the effects between the methods. Volunteers (n = 122) were randomly divided into static, ballistic, and PNF stretching groups and a control group. Before and after the 4 × 30 s stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle of the gastrocnemius medialis. Passive resistive torque (PRT) and maximum voluntary contraction (MVC) were measured with a dynamometer. Observation of muscle-tendon junction (MTJ) displacement with ultrasound allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate stiffness. Although RoM increased (static: +4.3%, ballistic: +4.5%, PNF: +3.5%), PRT (static: -11.4%, ballistic: -11.5%, PNF: -13,7%), muscle stiffness (static: -13.1%, ballistic: -20.3%, PNF: -20.2%), and muscle-tendon stiffness (static: -11.3%, ballistic: -10.5%, PNF: -13.7%) decreased significantly in all the stretching groups. Only in the PNF stretching group, the pennation angle in the stretched position (-4.2%) and plantar flexor MVC (-4.6%) decreased significantly. Multivariate analysis showed no clinically relevant difference between the stretching groups. The increase in RoM and the decrease in PRT and muscle-tendon stiffness could be explained by more compliant muscle tissue following a single static, ballistic, or PNF stretching exercise. © 2017 The Authors Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.

On MHD nonlinear stretching flow of Powell–Eyring nanomaterial

Directory of Open Access Journals (Sweden)

Tasawar Hayat

Full Text Available This communication addresses the magnetohydrodynamic (MHD flow of Powell–Eyring nanomaterial bounded by a nonlinear stretching sheet. Novel features regarding thermophoresis and Brownian motion are taken into consideration. Powell–Eyring fluid is electrically conducted subject to non-uniform applied magnetic field. Assumptions of small magnetic Reynolds number and boundary layer approximation are employed in the mathematical development. Zero nanoparticles mass flux condition at the sheet is selected. Adequate transformation yield nonlinear ordinary differential systems. The developed nonlinear systems have been computed through the homotopic approach. Effects of different pertinent parameters on velocity, temperature and concentration fields are studied and analyzed. Further numerical data of skin friction and heat transfer rate is also tabulated and interpreted. Keywords: Powell–Eyring fluid, Magnetohydrodynamics, Nanomaterial, Nonlinear stretching surface

Versatile Production of Poly(Epsilon-Caprolactone Fibers by Electrospinning Using Benign Solvents

Directory of Open Access Journals (Sweden)

Liliana Liverani

2016-04-01

Full Text Available The electrospinning technique is widely used for the fabrication of micro- and nanofibrous structures. Recent studies have focused on the use of less toxic and harmful solvents (benign solvents for electrospinning, even if those solvents usually require an accurate and longer process of optimization. The aim of the present work is to demonstrate the versatility of the use of benign solvents, like acetic acid and formic acid, for the fabrication of microfibrous and nanofibrous electrospun poly(epsilon-caprolactone mats. The solvent systems were also shown to be suitable for the fabrication of electrospun structures with macroporosity, as well as for the fabrication of composite electrospun mats, fabricated by the addition of bioactive glass (45S5 composition particles in the polymeric solution.

Cooperativity Between Oncogenic PKC Epsilon and Pten Loss in Prostate Cancer Progression

Science.gov (United States)

2016-10-01

are elevated in prostate cancer cells and that PKCε is causally associated with the elevated production and release of this chemokine. We also...Contents Page 1. Introduction …………………………………………………………. 1 2. Keywords……………………………………………………………. 1 3. Accomplishments………..…………………………………………... 1 4... INTRODUCTION A main goal is to understand how protein kinase C epsilon (PKCε) contributes to the progression of human prostate cancer. We and others have

Ontogeny of human natural killer (NK) cells: fetal NK cells mediate cytolytic function and express cytoplasmic CD3 epsilon,delta proteins

NARCIS (Netherlands)

Phillips, J. H.; Hori, T.; Nagler, A.; Bhat, N.; Spits, H.; Lanier, L. L.

1992-01-01

Natural killer (NK) cells have been defined as CD3 epsilon-, CD16+ and/or CD56+ lymphocytes that mediate major histocompatibility complex (MHC)-unrestricted cytotoxicity against certain tumors and virus-infected cells. Unlike T lymphocytes, NK cells do not rearrange or productively express T cell

A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

KAUST Repository

Chang, Y.-H.; Chen, S.-C.; Wang, T.-J.; Guo, J.

2018-01-01

Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non

Monorail snare technique for the recovery of stretched platinum coils: technical case report.

Science.gov (United States)

Fiorella, David; Albuquerque, Felipe C; Deshmukh, Vivek R; McDougall, Cameron G

2005-07-01

Coil stretching represents a potentially hazardous technical complication not infrequently encountered during the embolization of cerebral aneurysms. Often, the stretched coil cannot be advanced into the aneurysm or withdrawn intact. The operator is then forced to attempt to retract the damaged coil, which may result in coil breakage, leaving behind a significant length of potentially thrombogenic stretched coil material within the parent vessel. To overcome this problem, we devised a technique to snare the distal, unstretched, intact portion of the platinum coil by use of the indwelling microcatheter and stretched portion of the coil as a monorail guide. We have used this technique successfully in four patients to snare coils stretched during cerebral aneurysm embolization. Three of these patients were undergoing Neuroform (Boston Scientific/Target, Fremont, CA) stent-supported coil embolization of unruptured aneurysms. In all cases, the snare was advanced easily to the targeted site for coil engagement by use of the microcatheter as a monorail guide. Once the intact distal segment of the coil was ensnared, coil removal was uneventful, with no disturbance of the remainder of the indwelling coil pack or Neuroform stent. A 2-mm Amplatz Goose Neck microsnare (Microvena Corp., White Bear Lake, MN) was placed through a Prowler-14 microcatheter (Cordis Corp., Miami, FL). The hub of the indwelling SL-10 microcatheter (Boston Scientific, Natick, MA) was then cut away with a scalpel, leaving the coil pusher wire intact, and removed. The open 2-mm snare was then advanced over the outside of the coil pusher wire and microcatheter. The snare and Prowler-14 microcatheter were then advanced into the guiding catheter (6- or 7-French) as a unit over the indwelling SL-10 microcatheter. By use of the SL-10 microcatheter and coil as a "monorail" guide, the snare was advanced over and beyond the microcatheter and the stretched portion of the coil until the snare was in position to

Assessing the stretch-blow moulding FE simulation of PET over a large process window

Science.gov (United States)

Nixon, J.; Menary, G. H.; Yan, S.

2017-10-01

Injection stretch blow moulding has been extensively researched for numerous years and is a well-established method of forming thin-walled containers. This paper is concerned with validating the finite element analysis of the stretch-blow-moulding (SBM) process in an effort to progress the development of injection stretch blow moulding of poly(ethylene terephthalate). Extensive data was obtained experimentally over a wide process window accounting for material temperature, air flow rate and stretch-rod speed while capturing cavity pressure, stretch-rod reaction force, in-mould contact timing and material thickness distribution. This data was then used to assess the accuracy of the correlating FE simulation constructed using ABAQUS/Explicit solver and an appropriate user-defined viscoelastic material subroutine. Results reveal that the simulation was able to pick up the general trends of how the pressure, reaction force and in-mould contact timings vary with the variation in preform temperature and air flow rate. Trends in material thickness were also accurately predicted over the length of the bottle relative to the process conditions. The knowledge gained from these analyses provides insight into the mechanisms of bottle formation, subsequently improving the blow moulding simulation and potentially providing a reduction in production costs.

Directive Emission Obtained by Mu and Epsilon-Near-Zero Metamaterials

Directory of Open Access Journals (Sweden)

J. Yang

2009-06-01

Full Text Available In this work, we use Mu and Epsilon-Near-Zero (MENZ metamaterials to realize the substrates that can modify the emission of an embedded line source. Simulation results show that the cylindrical waves emitted from the line source can be perfectly converted to plane wave through the MENZ metamaterial slab with planar exit face. Hence the line source together with the metamaterial slab constructs a high directive slab antenna. The directive radiation pattern of the MENZ metamaterial-assisted slab antenna is independent on the thickness of the slab, the position of the line source, and the shape of the entrance face of the slab, but the slab with grooved entrance side will result in stronger far-field intensity. We also show that the MENZ metamaterials can be applied to the design of antenna array. Moreover, compared with the high directive slab antenna obtained by coordinate transformation approach, the MENZ metamaterial-assisted antenna is more preferable.

A workplace stretching program. Physiologic and perception measurements before and after participation.

Science.gov (United States)

Moore, T M

1998-12-01

The purpose of this study was to implement a primary prevention program in the workplace targeted to prevent muscle strains. Physiologic and perception measurements were taken before and after participation in a stretching program developed to improve flexibility through conditioning. A one group pre-test post-test design was used with 60 employees enrolled in a 36 session stretching program in the workplace. Flexibility was measured by a flexibility profile including the sit and reach test, bilateral body rotation measurements, and shoulder rotation measurements. A statistically significant increase was found in all flexibility measurements at the conclusion of the study for the participants as a total group. Perception, as measured by the Fox Physical Self Perception Profile, was statistically significant in relation to participants' perceptions of their body attractiveness, physical conditioning, and overall self worth at the program's conclusion. In addition, participants who completed the program had zero occurrences of musculoskeletal injuries during the 2 month period. The results of this study suggest that continued development and implementation of stretching programs in the workplace may benefit employees by increasing flexibility and potentially preventing injuries due to muscle strains. Stretching programs in the workplace also may improve components of employees' perceptions of their physical bodies.

Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

International Nuclear Information System (INIS)

Josefsson, Gabriella; Gamstedt, E. Kristofer; Ahvenainen, Patrik; Mushi, Ngesa Ezekiel

2015-01-01

The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils

Effect of stretching program in an industrial workplace on hamstring flexibility and sagittal spinal posture of adult women workers: a randomized controlled trial.

Science.gov (United States)

Muyor, José M; López-Miñarro, Pedro A; Casimiro, Antonio J

2012-01-01

To determine the effect of a stretching program performed in the workplace on the hamstring muscle extensibility and sagittal spinal posture of adult women. Fifty-eight adult women volunteers (mean age of 44.23 ± 8.87 years) from a private fruit and vegetable company were randomly assigned to experimental (n=27) or control (n=31) groups. The experimental group performed three exercises of hamstrings stretching of 20 seconds per exercise, three sessions a week for a period of 12 weeks. The control group did not participate in any hamstring stretching program. Hamstring flexibility was evaluated through the passive straight leg raise test and toe-touch test, performed both before and after the stretching program. Thoracic and lumbar curvatures and pelvic inclination were measured in relaxed standing and toe-touch test with a Spinal Mouse. Significant increases (p < 0.01) in toe-touch score and straight leg raise angle (in both legs) were found in the experimental group during post-test, while the control group showed a non-significant decrease for both toe-touch score and straight leg raise test. A significant decrease in thoracic curve and significant increase in pelvic inclination were found in the toe-touch test for the experimental group (p <0.05). However, no significant changes were found in standing posture for any group. Hamstring stretching exercises performed in the working place are effective for increasing hamstring muscle extensibility. This increase generates a more aligned thoracic curve and more anterior pelvic inclination when maximal trunk flexion is performed.

Origin of the blue shift of the CH stretching band for 2-butoxyethanol in water.

Science.gov (United States)

Katsumoto, Yukiteru; Komatsu, Hiroyuki; Ohno, Keiichi

2006-07-26

The blue shift of the isolated CD stretching band of 2-butoxyethanol (C4E1), which is observed for the aqueous solution during the dilution process, has been investigated by infrared (IR) spectroscopy and quantum chemical calculations. Mono-deuterium-labeled C4E1's were employed to remove the severe overlapping among the CH stretching bands. The isolated CD stretching mode of the alpha-methylene in the butoxy group shows a large blue shift, while those of the beta-methylene and methyl groups are not largely shifted. The spectral simulation results for the C4E1/H2O complexes indicate that the large blue shift of the CD stretching band of the butoxy group arises mainly from the hydration of the ether oxygen atom.

Tibialis anterior stretch reflex in early stance is suppressed by repetitive transcranial magnetic stimulation

DEFF Research Database (Denmark)

Zuur, Abraham T; Christensen, Mark Schram; Sinkjær, Thomas

2009-01-01

Abstract A rapid plantar flexion perturbation in the early stance phase of walking elicits a large stretch reflex in tibialis anterior (TA). In this study we use repetitive Transcranial Magnetic Stimulation (rTMS) to test if this response is mediated through a transcortical pathway. TA stretch...

Stretched exponential distributions in Nature and Economy: ``Fat tails'' with characteristic scales

OpenAIRE

Laherrère, Jean; Sornette, D.

1998-01-01

To account quantitatively for many reported ``natural'' fat tail distributions in Nature and Economy, we propose the stretched exponential family as a complement to the often used power law distributions. It has many advantages, among which to be economical with only two adjustable parameters with clear physical interpretation. Furthermore, it derives from a simple and generic mechanism in terms of multiplicative processes. We show that stretched exponentials describe very well the distributi...

Transient photoresponse in amorphous In-Ga-Zn-O thin films under stretched exponential analysis

Science.gov (United States)

Luo, Jiajun; Adler, Alexander U.; Mason, Thomas O.; Bruce Buchholz, D.; Chang, R. P. H.; Grayson, M.

2013-04-01

We investigated transient photoresponse and Hall effect in amorphous In-Ga-Zn-O thin films and observed a stretched exponential response which allows characterization of the activation energy spectrum with only three fit parameters. Measurements of as-grown films and 350 K annealed films were conducted at room temperature by recording conductivity, carrier density, and mobility over day-long time scales, both under illumination and in the dark. Hall measurements verify approximately constant mobility, even as the photoinduced carrier density changes by orders of magnitude. The transient photoconductivity data fit well to a stretched exponential during both illumination and dark relaxation, but with slower response in the dark. The inverse Laplace transforms of these stretched exponentials yield the density of activation energies responsible for transient photoconductivity. An empirical equation is introduced, which determines the linewidth of the activation energy band from the stretched exponential parameter β. Dry annealing at 350 K is observed to slow the transient photoresponse.

The effect of streptomycin on stretch-induced electrophysiological changes of isolated acute myocardial infarcted hearts in rats.

Science.gov (United States)

Fu, Lu; Cao, Jun-xian; Xie, Rong-sheng; Li, Jia; Han, Ying; Zhu, Li-qun; Dai, Ying-nan

2007-08-01

To explore whether the stretch of ischaemic myocardium could modulate the electrophysiological characteristics, especially repolarization via mechanoelectric feedback (MEF), as well as the effect of streptomycin (SM) on these changes. Methods Thirty-six wistar rats were randomly divided into four groups: control group (n = 9), SM group (n = 9), myocardial infarction (MI) group (n = 9), and MI + SM group (n = 9). After perfused on Langendorff, the isolated hearts were stretched for 5s by a ballon inflation of 0.2mL. After being stretched, the effect of the stretch was observed for 30s, including the 20, 20-70, 70, and 90% monophasic action potential duration (MAPD), i.e. MAPD(20), MAPD(20-70), MAPD(70), and MAPD(90), respectively, premature ventricular beats (PVB), and ventricular tachycardia (VT). Results The stretch caused a decrease in MAPD(20-70) (both P 0.05, except MAPD(20-70) between the control and SM groups, P maintenance of malignant arrhythmias. SM could significantly inhibit the occurrence of arrhythmias, which may correlate with the effect on blocking stretch-activated ion channels.

SEISMOTECTONIC DEFORMATION IN THE CONTACT AREA OF THE NAZCA AND SOUTH AMERICAN LITHOSPHERIC PLATES IN RELATION TO THE FEBRUARY 27, 2010 MW 8.8 MAULE EARTHQUAKE

Directory of Open Access Journals (Sweden)

P. G. Dyadkov

2017-01-01

Full Text Available Based on the data on earthquake focal mechanisms, we estimated seismotectonic deformation related to the 2010 Мw 8.8 Maule earthquake and analyzed the deformation at different depths. In the main seismic dislocation of the Maule earthquake and the northern area, the deformation field to a depth of 70 km is typical of subduction zones as evidenced by shortening in the direction of the oceanic plate subduction. Below a depth of 70 km, the deformation pattern changes sharply to horizontal stretching. After the main seismic event, as well as before it, nearlatitudinal shortening was dominant in the focal zone, while the region of the main seismic dislocations was surrounded by separate areas of near-latitudinal stretching, which is an opposite type of deformation. We conducted a detailed analysis of the seismotectonic deformations in the oceanic uplift area to the west of the deep-water trough and identified local zones of near-latitudinal stretching near the southern and northern boundaries of the future Maule earthquake zone. Detecting such zones can provide important data for early forecasting of regions wherein strong subduction-related earthquakes are being prepared.

An economical analysis of stretch-out for Angra 1

International Nuclear Information System (INIS)

Sakai, M.; Mascarenhas, H.A.

1990-01-01

An economical assessment of Angra 1 fuel cycle stretch-out is performed by means of NUCOST 1.0, a PWR power cost calculation code. International basic costs and an interest rate of 10%a were utilized. During the natural part of the fuel cycle an hypothetical capacity factor of 70% and in the stretch-out part a decrease in Plant's thermal efficiency have also been taken into account. The neutronic data were generated by FASER, MULTIMEDIUM, MEDIUM and PINPOW code system, simulating Angra 1 in the CAOC (constant Axial-Offset Control) operation. Assumming no proplems in the Plant's strecth-out phase, an optimum extension pont of 1 MWd/kg would be attained, what affords an US$700,000 savings by cycle when fuel and operation and maintenance costs are considered. (author) [pt

Automation of a single-DNA molecule stretching device

DEFF Research Database (Denmark)

Sørensen, Kristian Tølbøl; Lopacinska, Joanna M.; Tommerup, Niels

2015-01-01

We automate the manipulation of genomic-length DNA in a nanofluidic device based on real-time analysis of fluorescence images. In our protocol, individual molecules are picked from a microchannel and stretched with pN forces using pressure driven flows. The millimeter-long DNA fragments free...

Transient filament stretching rheometer I: force balance analysis

DEFF Research Database (Denmark)

Szabo, Peter

1997-01-01

The filament stretching device which is used increasingly as an apparatus for measuring extensional properties of polymeric liquids isanalysed. A force balance that includes the effects of inertia and surface tension is derived.The force balance may be used to correct for the effects of inertia...

Effects of hamstring stretch with pelvic control on pain and work ability in standing workers.

Science.gov (United States)

Han, Hyun-Il; Choi, Ho-Suk; Shin, Won-Seob

2016-11-21

Hamstring tightness induces posterior pelvic tilt and decreased lumbar lordosis, which can result in low back painOBJECTIVE: We investigated effects of hamstring stretch with pelvic control on pain and work ability in standing workers. One hundred adult volunteers from a standing workers were randomly assigned to pelvic control hamstring stretching (PCHS) (n = 34), general hamstring stretching (GHS) (n = 34), control (n = 32) groups. The control group was performed self-home exercise. All interventions were conducted 3 days per week for 6 weeks, and included in the hamstring stretching and lumbopelvic muscle strengthening. Outcomes were evaluated through the visual analog scale (VAS), straight leg raise test (SLR), sit and reach test (SRT), Oswestry disability index (ODI), and work ability index (WAI). Significant difference in VAS, SLR, SRT, ODI, and WAI were found in the PCHS and GHS groups. The control group was a significant difference only in ODI. The PCHS group showed a greater difference than the GHS group and control group in VAS, SLR, SRT, and ODI. The pelvic control hamstring stretch exercise would be more helpful in back pain reduction and improvement of work ability in an industrial setting.

The stretch zone of automotive steel sheets

Indian Academy of Sciences (India)

The stretch zone of automotive steel sheets. L' AMBRIŠKO1,∗ and L PEŠEK2. 1Institute of Structural Engineering, Faculty of Civil Engineering,. Technical University of Košice, Vysokoškolská 4, 042 00 Košice, Slovak Republic. 2Department of Materials Science, Faculty of Metallurgy,. Technical University of Košice, Letná 9, ...

The Considere condition and rapid stretching of linear and branched polymer melts

DEFF Research Database (Denmark)

McKinley, Gareth H; Hassager, Ole

1999-01-01

to larger Hencky strains as the number of branches is increased. Numerical computations at finite Deborah numbers also show that there is an optimal range of deformation rates over which homogeneous extensions can be maintained to large strain. We also consider other rapid homogeneous stretching...... deformations, such as biaxial and planar stretching, and show that the degree of stabilization afforded by inclusion of material with long-chain branching is a sensitive function of the imposed mode of deformation....

MESA models for the evolutionary status of the epsilon Aurigae disk-eclipsed binary system

Science.gov (United States)

Stencel, Robert E.; Gibson, Justus

2018-06-01

The brightest member of the class of disk-eclipsed binary stars is the Algol-like long-period binary, epsilon Aurigae (HD 31964, F0Iap + disk, http://adsabs.harvard.edu/abs/2016SPIE.9907E..17S ). Using MESA (Modules for Experiments in Stellar Astrophysics, version 9575), we have made an evaluation of its evolutionary state. We sought to satisfy several observational constraints, including: (1) requiring evolutionary tracks to pass close to the current temperature and luminosity of the primary star; (2) obtaining a period near the observed value of 27.1 years; (3) matching a mass function of 3.0; (4) concurrent Roche lobe overflow and mass transfer; (5) an isotopic ratio 12C / 13C = 5 and, (6) matching the interferometrically determined angular diameter. A MESA model starting with binary masses of 9.85 + 4.5 solar masses, with a 100 day initial period, produces a 1.2 + 10.6 solar masses result having a 547 day period, plus a single digit 12C / 13C ratio. These values were reached near an age of 20 Myr, when the donor star comes close to the observed luminosity and temperature for epsilon Aurigae A, as a post-RGB/pre-AGB star. Contemporaneously, the accretor then appears as an upper main sequence, early B-type star. This benchmark model can provide a basis for further exploration of this interacting binary, and other long period binary stars. This report has been submitted to MNRAS, along with a parallel investigation of mass transfer stream and disk sub-structure. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver.

Time-stretch microscopy based on time-wavelength sequence reconstruction from wideband incoherent source

International Nuclear Information System (INIS)

Zhang, Chi; Xu, Yiqing; Wei, Xiaoming; Tsia, Kevin K.; Wong, Kenneth K. Y.

2014-01-01

Time-stretch microscopy has emerged as an ultrafast optical imaging concept offering the unprecedented combination of the imaging speed and sensitivity. However, dedicated wideband and coherence optical pulse source with high shot-to-shot stability has been mandated for time-wavelength mapping—the enabling process for ultrahigh speed wavelength-encoded image retrieval. From the practical point of view, exploiting methods to relax the stringent requirements (e.g., temporal stability and coherence) for the source of time-stretch microscopy is thus of great value. In this paper, we demonstrated time-stretch microscopy by reconstructing the time-wavelength mapping sequence from a wideband incoherent source. Utilizing the time-lens focusing mechanism mediated by a narrow-band pulse source, this approach allows generation of a wideband incoherent source, with the spectral efficiency enhanced by a factor of 18. As a proof-of-principle demonstration, time-stretch imaging with the scan rate as high as MHz and diffraction-limited resolution is achieved based on the wideband incoherent source. We note that the concept of time-wavelength sequence reconstruction from wideband incoherent source can also be generalized to any high-speed optical real-time measurements, where wavelength is acted as the information carrier

Citizen Sky, Solving the Mystery of epsilon Aurigae

Science.gov (United States)

Turner, Rebecca; Price, A.; Kloppenborg, B.; Henden, A.

2010-01-01

Citizen Sky is a multi-year, NSF funded citizen science project involving the bright star eps Aur. The project was conceived by the IYA 2009 working group on Research Experiences for Students, Teachers, and Citizen-Scientists. Citizen Sky goes beyond simple observing to include a major data analysis component. The goal is to introduce the participant to the full scientific process from background research to paper writing for a peer-reviewed journal. It begins with a 10 Star Training Program of several types of binary and transient variable stars that are easy to observe from suburban locations with the naked eye. Participants then move on to monitoring the rare and mysterious 2009-2011 eclipse (already underway) of epsilon Aurigae. This object undergoes eclipses only every 27.1 years and each eclipse lasts nearly two years. The star is bright enough to be seen with the naked eye from most urban areas. Training will be provided in observing techniques as well as basic data analysis of photometric and visual datasets (light curve and period analysis). The project also involves two public workshops, one on observing (already held in August of 2009) and one on data analysis and scientific paper writing (to be held in 2010.) This project has been made possible by the National Science Foundation.

ACUTE EFFECTS OF STATIC STRETCHING, DYNAMIC EXERCISES, AND HIGH VOLUME UPPER EXTREMITY PLYOMETRIC ACTIVITY ON TENNIS SERVE PERFORMANCE

Directory of Open Access Journals (Sweden)

Ertugrul Gelen

2012-12-01

Full Text Available The purpose of this study was to compare the acute effects of static stretching; dynamic exercises and high volume upper extremity plyometric activity on tennis serve performance. Twenty-six elite young tennis players (15.1 ± 4.2 years, 167.9 ± 5.8 cm and 61.6 ± 8.1 kg performed 4 different warm-up (WU routines in a random order on non-consecutive days. The WU methods consisted of traditional WU (jogging, rally and serve practice (TRAD; traditional WU and static stretching (TRSS; traditional WU and dynamic exercise (TRDE; and traditional WU and high volume upper extremity plyometric activity (TRPLYP. Following each WU session, subjects were tested on a tennis serve ball speed test. TRAD, TRSS, TRDE and TRPLYO were compared by repeated measurement analyses of variance and post-hoc comparisons. In this study a 1 to 3 percent increase in tennis serve ball speed was recorded in TRDE and TRPLYO when compared to TRAD (p 0.05. ICCs for ball speed showed strong reliability (0.82 to 0.93 for the ball speed measurements.The results of this study indicate that dynamic and high volume upper extremity plyometric WU activities are likely beneficial to serve speed of elite junior tennis players.

Stretching of macromolecules and proteins

International Nuclear Information System (INIS)

Strick, T R; Dessinges, M-N; Charvin, G; Dekker, N H; Allemand, J-F; Bensimon, D; Croquette, V

2003-01-01

In this paper we review the biophysics revealed by stretching single biopolymers. During the last decade various techniques have emerged allowing micromanipulation of single molecules and simultaneous measurements of their elasticity. Using such techniques, it has been possible to investigate some of the interactions playing a role in biology. We shall first review the simplest case of a non-interacting polymer and then present the structural transitions in DNA, RNA and proteins that have been studied by single-molecule techniques. We shall explain how these techniques permit a new approach to the protein folding/unfolding transition

Goos-Hänchen shift of partially coherent light fields in epsilon-near-zero metamaterials

Science.gov (United States)

Ziauddin; Chuang, You-Lin; Qamar, Sajid; Lee, Ray-Kuang

2016-05-01

The Goos-Hänchen (GH) shifts in the reflected light are investigated both for p and s polarized partial coherent light beams incident on epsilon-near-zero (ENZ) metamaterials. In contrary to the coherent counterparts, the magnitude of GH shift becomes non-zero for p polarized partial coherent light beam; while GH shift can be relatively large with a small degree of spatial coherence for s polarized partial coherent beam. Dependence on the beam width and the permittivity of ENZ metamaterials is also revealed for partial coherent light fields. Our results on the GH shifts provide a direction on the applications for partial coherent light sources in ENZ metamaterials.

Evaluation of functional nerve recovery after reconstruction with a poly (DL-lactide-epsilon-caprolactone) nerve guide, filled with modified denatured muscle tissue

NARCIS (Netherlands)

Meek, MF; Den Dunnen, WFA; Schakenraad, JM; Robinson, PH

1996-01-01

The aim of this study was to compare the speed of functional nerve recovery after reconstruction with a biodegradable p(DLLA-epsilon -CL) nerve guide, as filled with either modified denatured muscle tissue (MDMT) or phosphate-buffered saline (PBS). To evaluate both motor and sensory nerve recovery,

Comparison of the Effects of Local Cryotherapy and Passive Cross-Body Stretch on Extensibility in Subjects with Posterior Shoulder Tightness

Directory of Open Access Journals (Sweden)

Kyue-nam Park

2014-03-01

Full Text Available The objective was to compare the immediate effects of local cryotherapy (LC and passive cross-body stretch on the extensibility of the posterior shoulder muscle in individuals with posterior shoulder tightness. Eighty-seven healthy subjects with a between-shoulder difference in internal rotation (IR range of motion (ROM greater than 10° were randomly divided into three groups: LC group, stretching group, and control group (n = 29 in each group. Subjects in the LC group received LC on infraspinatus and posterior deltoid muscles and subjects in the stretching group performed passive cross-body stretch. Stretch sensation was measured at the end range of passive IR and horizontal adduction (HA using numerical rating scale, and the pressure pain threshold (PPT at the infraspinatus and posterior deltoid muscles was measured using pressure algometry. Passive and active ROM of IR and HA of the glenohumeral joint were measured using an inclinometer. All measurements were performed at pre-intervention, post- intervention, and 10-min follow-up. Stretch sensation was significantly decreased and PPT was significantly increased in the LC and stretching groups at post-intervention, and these effects were maintained at 10-min follow-up, compared to the control group. Both the LC group and stretching group had a significantly greater increase in passive and active ROM of IR and HA, compared to the control group at post-intervention and 10-min follow-up. However, there were no significant differences in stretch sensation, PPT, or ROM of IR and HA between the LC group and stretching group. LC can be used to decrease the stretch sensation and increase PPT and ROM of IR and HA as much as a stretching exercise. LC could be an alternative method for increasing the restricted ROM of glenohumeral IR and HA for individuals with posterior shoulder tightness, especially for patients and sports players who have severe stretching discomfort.

Presentation And Management Of Gastroschisis: Experience In 8 ...

African Journals Online (AJOL)

Eleven were operated between 4 and 8 hours on presentation. Of the Six that had digital stretching of abdominal cavity, gastric suctioning/rectal irrigation and primary abdominal closure, three died and three survived. The two who had bowel gangrene for which resection/anastomosis and primary abdominal closure were ...

The effectiveness of combined prescription of ankle–foot orthosis and stretching program for the treatment of recalcitrant plantar fasciitis

Directory of Open Access Journals (Sweden)

Rehab A.E. Sallam

2016-01-01

Combined prescription of night-stretch ankle–foot orthosis and stretching exercises for plantar flexors and fascia had greater therapeutic effects compared with each treatment alone. Stretching exercises alone are not beneficial in the treatment of recalcitrant plantar fasciitis.

Curved Piezoelectric Actuators for Stretching Optical Fibers

Science.gov (United States)

Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

2008-01-01

Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

Local and Systemic Changes in Pain Sensitivity After 4 Weeks of Calf Muscle Stretching in a Nonpainful Population

DEFF Research Database (Denmark)

Bartholdy, Cecilie; Zangger, Graziella; Hansen, Lisbeth

2016-01-01

BACKGROUND: Stretching is often used in clinical practice for a variety of purposes, including pain therapy. The possible mechanism behind the effect of stretching remains to be clarified. AIM: To investigate whether 4 weeks of unilateral stretching of the calf muscles would affect local...... and central pain sensitivity. METHOD: This study was a randomized assessor-blinded clinical study. Healthy participants (age 18 to 40) were included and randomized. Participants in the intervention group were instructed to perform 2 stretching exercises targeting the calf muscles; 3 times 30 seconds, 7 days...... a week for 4 weeks on the dominant leg. Participants in the control group were instructed not to do any stretching for 4 weeks. Pressure pain threshold (PPT) and temporal summation (TS) of pressure pain were measured on the stretched calf, the contra-lateral calf, and contra-lateral lower arm using...

[Experiments with sausage meat on the formation of N epsilon-carboxymethyllysine].

Science.gov (United States)

Hartkopf, J; Erbersdobler, H F

1995-07-01

In model experiments the influence of ingredients normally used for sausage production to a meat homogenate on the formation of N epsilon-carboxymethyllysine (CML) was investigated. The formation of CML is obviously more promoted from the reaction of ascorbate with lysine than from that of glucose with lysine. The addition of ascorbate in a practical concentration yielded 35 mg, the addition of glucose only 23 mg compared to 17 mg CML/kg protein in the control sample. The addition of diphosphate in a practical concentration besides glucose significantly increased the CML values from 23 mg to 30 mg CML/kg protein. On the other hand, nitrite did not enhance the formation of CML (21 mg/kg protein) in the sausage when used in concentrations usually applied in meat processing. Generally the values found in the meat products are quite low compared to data in other foods like milk products.

One-Dimensional Chirality: Strong Optical Activity in Epsilon-Near-Zero Metamaterials.

Science.gov (United States)

Rizza, Carlo; Di Falco, Andrea; Scalora, Michael; Ciattoni, Alessandro

2015-07-31

We suggest that electromagnetic chirality, generally displayed by 3D or 2D complex chiral structures, can occur in 1D patterned composites whose components are achiral. This feature is highly unexpected in a 1D system which is geometrically achiral since its mirror image can always be superposed onto it by a 180 deg rotation. We analytically evaluate from first principles the bianisotropic response of multilayered metamaterials and we show that the chiral tensor is not vanishing if the system is geometrically one-dimensional chiral; i.e., its mirror image cannot be superposed onto it by using translations without resorting to rotations. As a signature of 1D chirality, we show that 1D chiral metamaterials support optical activity and we prove that this phenomenon undergoes a dramatic nonresonant enhancement in the epsilon-near-zero regime where the magnetoelectric coupling can become dominant in the constitutive relations.

Apolipoprotein E epsilon 4 allele and outcomes of traumatic spinal cord injury in a Chinese Han population.

Science.gov (United States)

Sun, Chongyi; Ji, Guangrong; Liu, Qingpeng; Yao, Meng

2011-10-01

The association between apolipoprotein E (APOE) epsilon 4 (ε4) allele and outcomes of traumatic spinal cord injury (SCI) is still controversial and ambiguous. The objective of this study was to test the hypothesis that APOE polymorphisms are associated with outcomes after SCI in Chinese Han patients. APOE polymorphisms were determined in 100 patients with cervical SCI (C3-C8). The genotype frequency of this polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism assay. Patients with an APOE ε4 allele had significantly less motor recovery during rehabilitation than did patients without an APOE ε4 allele (mean 3.7 vs. 6.1; P = 0.04) and a longer rehabilitation length of stay (LOS) (mean 117.4 vs. 94.5; P = 0.02), but better sensory-pinprick recovery (mean 6.1 vs. 4.0; P = 0.03). There were no significant differences by APOE ε4 allele status in sensory-light touch recovery or acute LOS. This study suggests that the APOE ε4 allele is associated with outcomes after SCI and longer rehabilitation LOS in Chinese Han patients.

Post-injury stretch promotes recovery in a rat model of muscle damage induced by lengthening contractions.

Science.gov (United States)

Mori, Tomohiro; Agata, Nobuhide; Itoh, Yuta; Inoue-Miyazu, Masumi; Mizumura, Kazue; Sokabe, Masahiro; Taguchi, Toru; Kawakami, Keisuke

2017-06-30

We investigated the cellular mechanisms and therapeutic effect of post-injury stretch on the recovery process from muscle injury induced by lengthening contractions (LC). One day after LC, a single 15-min bout of muscle stretch was applied at an intensity of 3 mNm. The maximal isometric torque was measured before and at 2-21 days after LC. The myofiber size was analyzed at 21 days after LC. Developmental myosin heavy chain-immunoreactive (dMHC-ir) cells, a marker of regenerating myofibers, were observed in the early recovery stage (2-5 days after LC). We observed that LC-induced injury markedly decreased isometric torque and myofiber size, which recovered faster in rats that underwent stretch than in rats that did not. Regenerating myofiber with dMHC-ir cells was observed earlier in rats that underwent stretch. These results indicate that post-injury stretch may facilitate the regeneration and early formation of new myofibers, thereby promoting structural and functional recovery from LC-induced muscle injury.

Towards clinical application of RayStretch for heterogeneity corrections in LDR permanent 125I prostate brachytherapy.

Science.gov (United States)

Hueso-González, Fernando; Ballester, Facundo; Perez-Calatayud, Jose; Siebert, Frank-André; Vijande, Javier

RayStretch is a simple algorithm proposed for heterogeneity corrections in low-dose-rate brachytherapy. It is built on top of TG-43 consensus data, and it has been validated with Monte Carlo (MC) simulations. In this study, we take a real clinical prostate implant with 71 125 I seeds as reference and we apply RayStretch to analyze its performance in worst-case scenarios. To do so, we design two cases where large calcifications are located in the prostate lobules. RayStretch resilience under various calcification density values is also explored. Comparisons against MC calculations are performed. Dose-volume histogram-related parameters like prostate D 90 , rectum D 2cc , or urethra D 10 obtained with RayStretch agree within a few percent with the detailed MC results for all cases considered. The robustness and compatibility of RayStretch with commercial treatment planning systems indicate its applicability in clinical practice for dosimetric corrections in prostate calcifications. Its use during intraoperative ultrasound planning is foreseen. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Light-microscopic and electron-microscopic evaluation of short-term nerve regeneration using a biodegradable poly(DL-lactide-epsilon-caprolacton) nerve guide

NARCIS (Netherlands)

denDunnen, WFA; Stokroos, [No Value; Blaauw, EH; Holwerda, A; Pennings, AJ; Robinson, PH; Schakenraad, JM

The aim of this study was to evaluate short-term peripheral nerve regeneration across a IO-mm gap, using a biodegradable poly(DL-lactide-epsilon-caprolacton) nerve guide, with an internal diameter of 1.5 mm and a wall thickness of 0.30 mm. To do so, we evaluated regenerating nerves using light

Stretched inverse opal colloid crystal substrates-induced orientation of fibroblast

International Nuclear Information System (INIS)

Wang, Y C; Tang, Z M; Feng, Z Q; Xie, Z Y; Gu, Z Z

2010-01-01

Recently, there has been increasing interest in studying the interaction between mammalian cells and nanometer-sized structures. However, the effect of nanostructures on cell behavior, such as cell morphology and alignment, is still largely unknown. Inverse opal colloid crystal substrates, which can be stretched to produce nano-scale pore structures of different degrees of orientation, serve as a convenient model system to study the effect of nanotopography on cell morphology and cell alignment. In this work, we fabricated inverse opal colloidal crystal films that were either unstretched or stretched to three, four or six times their original length, producing pore structures of increasing degree of orientation. Human dermal fibroblast-fetal (HDF-f) cells were seeded and cultured on these four types of substrates. The results from fluorescence microscopy and scanning electron microscopy indicated that cells showed the highest degree of alignment when cultured on inverse opal colloid crystal films that were stretched the most (six times original length). The results also demonstrated that the orientation of nanostructures could affect both the morphology and growth direction of fibroblasts. The ability to control the direction of cell growth through the engineering of nanostructures could have important applications in tissue engineering, especially for tissues with anisotropic structures, such as cardiac muscle, blood vessel, tendon and ligament.

Stretched inverse opal colloid crystal substrates-induced orientation of fibroblast

Energy Technology Data Exchange (ETDEWEB)

Wang, Y C; Tang, Z M; Feng, Z Q; Xie, Z Y; Gu, Z Z, E-mail: gu@seu.edu.c [State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)

2010-06-01

Recently, there has been increasing interest in studying the interaction between mammalian cells and nanometer-sized structures. However, the effect of nanostructures on cell behavior, such as cell morphology and alignment, is still largely unknown. Inverse opal colloid crystal substrates, which can be stretched to produce nano-scale pore structures of different degrees of orientation, serve as a convenient model system to study the effect of nanotopography on cell morphology and cell alignment. In this work, we fabricated inverse opal colloidal crystal films that were either unstretched or stretched to three, four or six times their original length, producing pore structures of increasing degree of orientation. Human dermal fibroblast-fetal (HDF-f) cells were seeded and cultured on these four types of substrates. The results from fluorescence microscopy and scanning electron microscopy indicated that cells showed the highest degree of alignment when cultured on inverse opal colloid crystal films that were stretched the most (six times original length). The results also demonstrated that the orientation of nanostructures could affect both the morphology and growth direction of fibroblasts. The ability to control the direction of cell growth through the engineering of nanostructures could have important applications in tissue engineering, especially for tissues with anisotropic structures, such as cardiac muscle, blood vessel, tendon and ligament.

Lamb's plane problem in a thermo-elastic micropolar medium with stretch

Directory of Open Access Journals (Sweden)

T. K. Chadha

1987-01-01

Full Text Available A study is made of the Lamb plane problem in a thermo-elastic micropolar medium with the effect of stretch. The problem is solved for an arbitrary, normal load distribution by using the double Fourier transform. The displacement components, force stress, couple stress, vector first moment and the temperature field are determined for a half space subjected to an arbitrary normal load. Two special cases of a horizontal force and a torque which are oscillating with a frequency ω have been investigated. It is shown that results of this analysis reduce to those without stretch.

Stiffness of individual quadriceps muscle assessed using ultrasound shear wave elastography during passive stretching

Directory of Open Access Journals (Sweden)

Jingfei Xu

2018-04-01

Full Text Available Background: Until recently it has not been possible to isolate the mechanical behavior of individual muscles during passive stretching. Muscle shear modulus (an index of muscle stiffness measured using ultrasound shear wave elastography can be used to estimate changes in stiffness of an individual muscle. The aims of the present study were (1 to determine the shear modulus–knee angle relationship and the slack angle of the vastus medialis oblique (VMO, rectus femoris (RF, and vastus lateralis (VL muscles; (2 to determine whether this differs between the muscles. Methods: Nine male rowers took part in the study. The shear modulus of VMO, RF, and VL muscles was measured while the quadriceps was passively stretched at 3°/s. The relationship between the muscle shear modulus and knee angle was plotted as shear modulus–knee angle curve through which the slack angle of each muscle was determined. Results: The shear modulus of RF was higher than that of VMO and VL when the muscles were stretched over 54° (all p  0.05. The slack angle was similar among the muscles: 41.3° ± 10.6°, 44.3° ± 9.1°, and 44.3° ± 5.6° of knee flexion for VMO, RF, and VL, respectively (p = 0.626. Conclusion: This is the first study to experimentally determine the muscle mechanical behavior of individual heads of the quadriceps during passive stretching. Different pattern of passive tension was observed between mono- and bi-articular muscles. Further research is needed to determine whether changes in muscle stiffness are muscle-specific in pathological conditions or after interventions such as stretching protocols. Keywords: Muscle tension, Optimal length, Shear modulus, Slack angle, Stretch, Ultrasonography, Vastus lateralis, Vastus medialis

Tip opening of premixed bunsen flames: Extinction with negative stretch and local Karlovitz number

KAUST Repository

Vu, Tranmanh

2015-04-01

The characteristics of tip openings in premixed bunsen flames have been studied experimentally by measuring OH radicals from laser-induced fluorescence and tip curvatures from chemiluminescent images. Results showed that the tip opening occurred at a constant equivalence ratio and was independent of the jet velocity in propane/air mixtures. The observation of a local extinction phenomenon of the negatively stretched flame due to the flame curvature could not be consistently explained based on flame stretch or the Karlovitz number, since they varied appreciably with the jet velocity. The concept of the local Karlovitz number (KaL) was introduced, which is defined as the ratio of the characteristic reaction time in the normal direction for a stretched flame to the characteristic flow time in the tangential direction for the stretched flame. The local Karlovitz number maintained a constant value under tip opening conditions, irrespective of the jet velocity. Tip opening occurred at a reasonably constant local Karlovitz number of about ~1.72 when the nitrogen dilution level in propane and n-butane fuels was varied.

SU-F-BRD-08: Guaranteed Epsilon-Optimal Treatment Plans with Minimum Number of Beams for SBRT Using RayStation

International Nuclear Information System (INIS)

Yarmand, H; Winey, B; Craft, D

2014-01-01

Purpose: To efficiently find quality-guaranteed treatment plans with the minimum number of beams for stereotactic body radiation therapy using RayStation. Methods: For a pre-specified pool of candidate beams we use RayStation (a treatment planning software for clinical use) to identify the deliverable plan which uses all the beams with the minimum dose to organs at risk (OARs) and dose to the tumor and other structures in specified ranges. Then use the dose matrix information for the generated apertures from RayStation to solve a linear program to find the ideal plan with the same objective and constraints allowing use of all beams. Finally we solve a mixed integer programming formulation of the beam angle optimization problem (BAO) with the objective of minimizing the number of beams while remaining in a predetermined epsilon-optimality of the ideal plan with respect to the dose to OARs. Since the treatment plan optimization is a multicriteria optimization problem, the planner can exploit the multicriteria optimization capability of RayStation to navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing quality. For the numerical experiments two liver cases and one lung case with 33 non-coplanar beams are considered. Results: The ideal plan uses an impractically large number of beams. The proposed technique reduces the number of beams to the range of practical application (5 to 9 beams) while remaining in the epsilon-optimal range of 1% to 5% optimality gap. Conclusion: The proposed method can be integrated into a general algorithm for fast navigation of the ideal dose distribution Pareto surface and finding the treatment plan with the minimum number of beams, which corresponds to the delivery time, in epsilon-optimality range of the desired ideal plan. The project was supported by the Federal Share of program income

SU-F-BRD-08: Guaranteed Epsilon-Optimal Treatment Plans with Minimum Number of Beams for SBRT Using RayStation

Energy Technology Data Exchange (ETDEWEB)

Yarmand, H; Winey, B; Craft, D [Massachusetts General Hospital, Boston, MA (United States)

2014-06-15

Purpose: To efficiently find quality-guaranteed treatment plans with the minimum number of beams for stereotactic body radiation therapy using RayStation. Methods: For a pre-specified pool of candidate beams we use RayStation (a treatment planning software for clinical use) to identify the deliverable plan which uses all the beams with the minimum dose to organs at risk (OARs) and dose to the tumor and other structures in specified ranges. Then use the dose matrix information for the generated apertures from RayStation to solve a linear program to find the ideal plan with the same objective and constraints allowing use of all beams. Finally we solve a mixed integer programming formulation of the beam angle optimization problem (BAO) with the objective of minimizing the number of beams while remaining in a predetermined epsilon-optimality of the ideal plan with respect to the dose to OARs. Since the treatment plan optimization is a multicriteria optimization problem, the planner can exploit the multicriteria optimization capability of RayStation to navigate the ideal dose distribution Pareto surface and select a plan of desired target coverage versus OARs sparing, and then use the proposed technique to reduce the number of beams while guaranteeing quality. For the numerical experiments two liver cases and one lung case with 33 non-coplanar beams are considered. Results: The ideal plan uses an impractically large number of beams. The proposed technique reduces the number of beams to the range of practical application (5 to 9 beams) while remaining in the epsilon-optimal range of 1% to 5% optimality gap. Conclusion: The proposed method can be integrated into a general algorithm for fast navigation of the ideal dose distribution Pareto surface and finding the treatment plan with the minimum number of beams, which corresponds to the delivery time, in epsilon-optimality range of the desired ideal plan. The project was supported by the Federal Share of program income

Melting heat transfer in boundary layer stagnation-point flow towards a stretching/shrinking sheet

International Nuclear Information System (INIS)

Bachok, Norfifah; Ishak, Anuar; Pop, Ioan

2010-01-01

An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique.

Bounded energy states in homogeneous turbulent shear flow - An alternative view

Science.gov (United States)

Bernard, P. S.; Speziale, C. G.

1992-01-01

The equilibrium structure of homogeneous turbulent shear flow is investigated from a theoretical standpoint. Existing turbulence models, in apparent agreement with physical and numerical experiments, predict an unbounded exponential time growth of the turbulent kinetic energy and dissipation rate; only the anisotropy tensor and turbulent time scale reach a structural equilibrium. It is shown that if a residual vortex stretching term is maintained in the dissipation rate transport equation, then there can exist equilibrium solutions, with bounded energy states, where the turbulence production is balanced by its dissipation. Illustrative calculations are presented for a k-epsilon model modified to account for net vortex stretching.

Adaptation of the dermal collagen structure of human skin and scar tissue in response to stretch: An experimental study

NARCIS (Netherlands)

Verhaegen, Pauline D.; Schouten, Hennie J.; Tigchelaar-Gutter, Wikky; van Marle, Jan; van Noorden, Cornelis J.; Middelkoop, Esther; van Zuijlen, Paul P.

2012-01-01

Surgeons are often faced with large defects that are difficult to close. Stretching adjacent skin can facilitate wound closure. In clinical practice, intraoperative stretching is performed in a cyclical or continuous fashion. However, exact mechanisms of tissue adaptation to stretch remain unclear.

Short pulse generation from a passively mode-locked fiber optical parametric oscillator with optical time-stretch.

Science.gov (United States)

Qiu, Yi; Wei, Xiaoming; Du, Shuxin; Wong, Kenneth K Y; Tsia, Kevin K; Xu, Yiqing

2018-04-16

We propose a passively mode-locked fiber optical parametric oscillator assisted with optical time-stretch. Thanks to the lately developed optical time-stretch technique, the onset oscillating spectral components can be temporally dispersed across the pump envelope and further compete for the parametric gain with the other parts of onset oscillating sidebands within the pump envelope. By matching the amount of dispersion in optical time-stretch with the pulse width of the quasi-CW pump and oscillating one of the parametric sidebands inside the fiber cavity, we numerically show that the fiber parametric oscillator can be operated in a single pulse regime. By varying the amount of the intracavity dispersion, we further verify that the origin of this single pulse mode-locking regime is due to the optical pulse stretching and compression.

The Magnetohydrodynamic Boundary Layer Flow of a Nanofluid past a Stretching/Shrinking Sheet with Slip Boundary Conditions

Directory of Open Access Journals (Sweden)

Syahira Mansur

2014-01-01

Full Text Available The magnetohydrodynamic (MHD boundary layer flow of a nanofluid past a stretching/shrinking sheet with velocity, thermal, and solutal slip boundary conditions is studied. Numerical solutions to the governing equations were obtained using a shooting method. The skin friction coefficient and the local Sherwood number increase as the stretching/shrinking parameter increases. However, the local Nusselt number decreases with increasing the stretching/shrinking parameter. The range of the stretching/shrinking parameter for which the solution exists increases as the velocity slip parameter and the magnetic parameter increase. For the shrinking sheet, the skin friction coefficient increases as the velocity slip parameter and the magnetic parameter increase. For the stretching sheet, it decreases when the velocity slip parameter and the magnetic parameter increase. The local Nusselt number diminishes as the thermal slip parameter increases while the local Sherwood number decreases with increasing the solutal slip parameter. The local Nusselt number is lower for higher values of Lewis number, Brownian motion parameter, and thermophoresis parameter.

Static stretching vs. dynamic warm-ups: a comparison of their effects on torque and electromyography output of the quadriceps and hamstring muscles.

Science.gov (United States)

Williams, N; Coburn, J; Gillum, T