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Sample records for macro-residual strains due

  1. Spread of Amikacin Resistance in Acinetobacter baumannii Strains Isolated in Spain Due to an Epidemic Strain

    PubMed Central

    Vila, Jordi; Ruiz, Joaquim; Navia, Margarita; Becerril, Berta; Garcia, Isabel; Perea, Sofia; Lopez-Hernandez, Inmaculada; Alamo, Isabel; Ballester, Frederic; Planes, Anna M.; Martinez-Beltran, Jesus; De Anta, Teresa Jimenez

    1999-01-01

    Sixteen amikacin-resistant clinical Acinetobacter baumannii isolates from nine different hospitals in Spain were investigated to determine whether the high incidence of amikacin-resistant A. baumannii was due to the dissemination of an amikacin-resistant strain or to the spread of an amikacin resistance gene. The epidemiological relationship studied by repetitive extragenic palindromic PCR and low-frequency restriction analysis of chromosomal DNA showed that the same clone was isolated in eight of nine hospitals, although other clones were also found. The strains were studied for the presence of the aph(3′)-VIa and aac(6′)-I genes, which encode enzymes which inactivate amikacin, by PCR. All 16 clinical isolates had positive PCRs with primers specific for the amplification of the aph(3′)-VIa gene, whereas none had a positive reaction for the amplification of the aac(6′)-I gene. Therefore, the high incidence of amikacin resistance among clinical A. baumannii isolates in Spain was mainly due to an epidemic strain, although the spread of the aph(3′)-VI gene cannot be ruled out. PMID:9986846

  2. Spontaneous bacterial peritonitis due to a group IIk-2 strain.

    PubMed Central

    Dhawan, V K; Rajashekaraiah, K R; Metzger, W I; Rice, T W; Kallick, C A

    1980-01-01

    This paper describes a patient with spontaneous bacterial peritonitis caused by a group IIk-2 strain. No other organism was isolated from the peritoneal fluid cultured aerobically and anaerobically. PMID:7381015

  3. Are quantum dots in unexpected locations due to strain?

    NASA Astrophysics Data System (ADS)

    Zimmerman, Neil; Thorbeck, Ted

    It is a fairly common occurrence that, in top-gated Si quantum dots, the dots appear in reproducible but unexpected positions. For instance, sometimes a group will make gates in order to electrostatically generate tunnel barriers, but discover that the quantum dot is formed underneath the gate rather than between two barrier gates. We will discuss the possibility that such quantum dots arise from the mechanical strain induced by the gate. The model is simple: i) We simulate metal or polysilicon gates on top of a Si/SiO2 wafer, and calculate the stress and strain from differential thermal contraction of the materials; ii) Using the fact that the energy of the Si conduction band depends on strain through the deformation potential, we then convert the strain modulation to a potential energy modulation. As an example, we find that, for a single Al gate, there is a potential well directly underneath the gate with the size of a few meV, in agreement with recent experimental results. We also show that polysilicon gates will not produce such strain-induced quantum dots.

  4. Strain intermittency due to avalanches in ferroelastic and porous materials.

    PubMed

    Soprunyuk, Viktor; Puchberger, Sabine; Tröster, Andreas; Vives, Eduard; Salje, Ekhard; Schranz, Wilfried

    2017-04-06

    The avalanche statistics in porous materials and ferroelastic domain wall systems has been studied for slowly increasing compressive uniaxial stress with stress rates between 0.2 and 17 kPa/s. Velocity peaks vm=dh/dt are calculated from the measured strain drops and used to determine the corresponding Energy distributions N(E = vm2). Power law distributions N(vm2) ~(vm2) have been obtained over 4-6 decades. For most of the porous materials and domain wall systems an exponent ε= 1.5 ± 0.1 was obtained in good agreement with mean-field theory of the interface pinning transition. For charcoal, shale and calcareous schist we found significant deviations of the exponents from mean-field values in agreement with recent acoustic emission experiments.

  5. Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles.

    PubMed

    Zhao, Wei; Ji, Songbai

    2017-04-01

    Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29-17.89 % in the whole brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9 %) but not pattern (correlation coefficient of 0.94-0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91 % on average, with a typical range of 0-6 %). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future.

  6. Monitoring Concrete Deterioration Due to Reinforcement Corrosion by Integrating Acoustic Emission and FBG Strain Measurements

    PubMed Central

    Li, Weijie; Xu, Changhang; Ho, Siu Chun Michael; Wang, Bo; Song, Gangbing

    2017-01-01

    Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface. PMID:28327510

  7. Monitoring Concrete Deterioration Due to Reinforcement Corrosion by Integrating Acoustic Emission and FBG Strain Measurements.

    PubMed

    Li, Weijie; Xu, Changhang; Ho, Siu Chun Michael; Wang, Bo; Song, Gangbing

    2017-03-22

    Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface.

  8. Neonatal infections due to multi-resistant strains: Epidemiology, current treatment, emerging therapeutic approaches and prevention.

    PubMed

    Tzialla, Chryssoula; Borghesi, Alessandro; Pozzi, Margherita; Stronati, Mauro

    2015-12-07

    Severe infections represent the main cause of neonatal mortality accounting for more than one million neonatal deaths worldwide every year. Antibiotics are the most commonly prescribed medications in neonatal intensive care units. The benefits of antibiotic therapy when indicated are clearly enormous, but the continued and widespread use of antibiotics has generated over the years a strong selective pressure on microorganisms, favoring the emergence of resistant strains. Health agencies worldwide are galvanizing attention toward antibiotic resistance in gram-positive and gram-negative bacteria. Infections in neonatal units due to multidrug and extensively multidrug resistant bacteria are rising and are already seriously challenging antibiotic treatment options. While there is a growing choice of agents against multi-resistant gram-positive bacteria, new options for multi-resistant gram-negative bacteria in the clinical practice have decreased significantly in the last 20 years making the treatment of infections caused by multidrug-resistant pathogens challenging mostly in neonates. Treatment options are currently limited and will be some years before any new treatment for neonates become available for clinical use, if ever. The aim of the review is to highlight the current knowledge on antibiotic resistance in the neonatal population, the possible therapeutic choices, and the prevention strategies to adopt in order to reduce the emergency and spread of resistant strains.

  9. A case of intoxication due to a highly cytotoxic Bacillus cereus strain isolated from cooked chicken.

    PubMed

    López, Ana C; Minnaard, Jessica; Pérez, Pablo F; Alippi, Adriana M

    2015-04-01

    Outbreaks of Bacillus cereus infection/intoxication are not commonly reported because symptoms are often mild, and the disease is self-limiting. However, hypervirulent strains increase health risks. We report a case, which occurred in Argentina, of severe food poisoning illness on a healthy adult woman associated to B. cereus strain MVL2011. The studied strain was highly cytotoxic, showed high ability to detach Caco-2 cells and was positive for the hblA, hblB, and hblC genes of the hbl complex, bceT, entS and ces. As it is considered that B. cereus emetic cluster evolved from a panmictic population of diarrheal strains, B. cereus MVL2011 could constitute an intermediate strain between diarrheal and emetic strains.

  10. In vitro quantification of strain patterns in the craniofacial skeleton due to masseter and temporalis activities.

    PubMed

    Maloul, Asmaa; Regev, Eran; Whyne, Cari M; Beek, Marteen; Fialkov, Jeffrey A

    2012-09-01

    Many complications in craniofacial surgery can be attributed to a lack of characterization of facial skeletal strain patterns. This study aimed to delineate human midfacial strain patterns under uniform muscle loading. The left sides of 5 fresh-frozen human cadaveric heads were dissected of all soft tissues except the temporalis and masseter muscles. Tensile forces were applied to the free mandibular ends of the muscles. Maxillary alveolar arches were used to restrain the skulls. Eight strain gauges were bonded to the surface of the midface to measure the strain under single muscle loading conditions (100 N). Maxillary strain gauges revealed a biaxial load state for both muscles. Thin antral bone experienced high maximum principal tensile strains (maximum of 685.5 με) and high minimum principal compressive strains (maximum of -722.44 με). Similar biaxial patterns of lower magnitude were measured on the zygoma (maximum of 208.59 με for maximum principal strains and -78.11 με for minimum principal strains). Results, consistent for all specimens and counter to previously accepted concepts of biomechanical behavior of the midface under masticatory muscle loading, included high strain in the thin maxillary antral wall, rotational bending through the maxilla and zygoma, and a previously underestimated contribution of the temporalis muscle. This experimental model produced repeatable strain patterns quantifying the mechanics of the facial skeleton. These new counterintuitive findings underscore the need for accurate characterization of craniofacial strain patterns to address problems in the current treatment methods and develop robust design criteria.

  11. Atomistic mechanisms of strain relaxation due to ductile void growth in ultrathin films of face-centered-cubic metals

    NASA Astrophysics Data System (ADS)

    Gungor, M. Rauf; Maroudas, Dimitrios

    2005-06-01

    A comprehensive computational analysis is reported of the atomistic mechanisms of strain relaxation and failure in free-standing Cu thin films under applied biaxial tensile strain for strain levels up to 6%. The analysis focuses on nanometer-scale-thick films with a preexisting void extending across the film thickness and the film plane oriented normal to the [111] crystallographic direction. Our computational study is based on isothermal-isostrain large-scale molecular-dynamics simulations within an embedded-atom-method parametrization for Cu. Our analysis has revealed various regimes in the film's mechanical response as the applied strain level increases. Within the considered strain range, after an elastic response at a low strain (<2%), void growth is the major strain relaxation mechanism mediated by the emission of perfect screw dislocation pairs from the void surface and subsequent dislocation propagation; as a result, a plastic zone forms around the void. Plastic deformation is accompanied by the glide motion of the dislocations emitted from the void surface, void surface morphological transitions, formation of a step pattern on the film's surfaces, dislocation jogging, vacancy generation due to gliding jogged dislocations, dislocation-vacancy interactions, vacancy pipe diffusion along dislocation cores, as well as dislocation-dislocation interactions. The increase in film surface roughness with increasing strain eventually leads to nucleation and propagation from the film surfaces of threading dislocation loops, which ultimately break up when they reach the opposite free surface of the thin film.

  12. Comparative evaluation of two vaccine candidates against experimental leishmaniasis due to Leishmania major infection in four inbred mouse strains.

    PubMed

    Benhnini, Fouad; Chenik, Mehdi; Laouini, Dhafer; Louzir, Hechmi; Cazenave, Pierre André; Dellagi, Koussay

    2009-11-01

    Experimental leishmaniasis in BALB/c and C57BL/6 mice are the most investigated murine models that were used for the preclinical evaluation of Leishmania vaccine candidates. We have previously described two new inbred mouse strains named PWK and MAI issued from feral founders that also support the development of experimental leishmaniasis due to L. major. In this study, we sought to determine whether different mouse inbred strains generate concordant or discordant results when used to evaluate the potential of Leishmania proteins to protect against experimental leishmaniasis. To this end, two Leishmania proteins, namely, LACK (for Leishmania homolog of receptor for activated C kinase) and LmPDI (for L. major protein disulfide isomerase) were compared for their capacity to protect against experimental leishmaniasis in PWK, MAI, BALB/c, and C57BL/6 inbred mouse strains. Our data show that the capacity of Leishmania proteins to confer protection depends on the mouse strain used, stressing the important role played by the genetic background in shaping the immune response against the pathogen. These results may have important implications for the preclinical evaluation of candidate Leishmania vaccines: rather than using a single mouse strain, a panel of different inbred strains of various genetic backgrounds should be tested in parallel. The antigen that confers protection in the larger range of inbred strains may have better chances to be also protective in outbred human populations and should be selected for clinical trials.

  13. Infections due to gentamicin-resistant Staphylococcus aureus strain in a nursery for neonatal infants.

    PubMed Central

    Vogel, L; Nathan, C; Sweeney, H M; Kabins, S A; Cohen, S

    1978-01-01

    An apparently homogeneous strain of Staphylococcus aureus resistant to gentamicin (Gmr), kanamycin, tobramycin, and sisomicin, but susceptible to amikacin and netilmicin, caused multiple infections in neonatal infants in a special care nursery. Nasal cultures revealed a high rate of carriage of the Gmr staphylococcus in infants without clinical infection. Segregating patients according to a modified cohort system and use of careful aseptic techniques led to apparent elimination of the Gmr strain. The resistance to aminoglycosides in this strain was mediated by an aminoglycoside 6'-N-acetyltransferase and a gentamicin phosphotransferase. Genetic determinants for these enzymes were borne on a circular covalently closed plasmid of approximately 11 megadaltons. These resistance determinants closely resemble those found in isolates of S. aureus that have caused nosocomial infections in patients in Europe. PMID:263886

  14. Determining horizontal displacement and strains due to subsidence. Rept. of Investigations/1991

    SciTech Connect

    Tandanand, S.; Powell, L.R.

    1991-01-01

    Horizontal displacements and ground strains induced by mine subsidence are significant information needed for calculating damage and developing precautions against subsidence effects on surface structures. To devise a simple method for determining the surface horizontal displacements and strains simultaneously with the subsidence prediction, the U.S. Bureau of Mines examined the significance of the tilt number, which is the proportionality constant in the relationship between the horizontal displacement and the slope of the subsidence profile. The ratio of the tilt number to the critical radius of the subsidence trough is identical to the ratio of the maximum possible horizontal displacement to the full subsidence, which is found to be constant in most European coalfields. If this ratio is known for a particular minesite in the United States, then horizontal displacement and ground strains can be readily obtained from the primary subsidence data.

  15. Strain distribution due to surface domains: a self-consistent approach with respect to surface elasticity

    PubMed Central

    Fuhr, Javier

    2015-01-01

    Summary Elastically mediated interactions between surface domains are classically described in terms of point forces. Such point forces lead to local strain divergences that are usually avoided by introducing a poorly defined cut-off length. In this work, we develop a self-consistent approach in which the strain field induced by the surface domains is expressed as the solution of an integral equation that contains surface elastic constants, S ij. For surfaces with positive S ij the new approach avoids the introduction of a cut-off length. The classical and the new approaches are compared in case of 1-D periodic ribbons. PMID:25821670

  16. Impact comminution of solids due to local kinetic energy of high shear strain rate: II-Microplane model and verification

    NASA Astrophysics Data System (ADS)

    Caner, Ferhun C.; Bažant, Zdeněk P.

    2014-03-01

    The new theory presented in the preceding paper, which models the dynamic comminution of concrete due to very high shear strain rate, is now compared to recent test data on the penetration of projectiles through concrete walls of different thicknesses, ranging from 127 to 254 mm. These data are analyzed by an explicit finite element code using the new microplane constitutive model M7 for concrete, which was previously shown to provide the most realistic description of the quasi-static uni-, bi- and tri-axial test data with complex loading path and unloading. Model M7 incorporates the quasi-static strain rate effects due viscoelasticity and to the rate of cohesive crack debonding based on activation energy of bond ruptures, which are expected to extend to very high rates. Here model M7 is further enhanced by apparent viscosity capturing the energy dissipation due to the strain-rate effect of comminution. The maximum shear strain rates in the computations are of the order of 105 s-1. The simulations document that, within the inevitable uncertainties, the measured exit velocities of the projectiles can be matched quite satisfactorily and the observed shapes of the entry and exit craters can be reproduced correctly.

  17. Changing epidemiology of invasive Haemophilus influenzae in Ontario, Canada: evidence for herd effects and strain replacement due to Hib vaccination.

    PubMed

    Adam, H J; Richardson, S E; Jamieson, F B; Rawte, P; Low, D E; Fisman, D N

    2010-05-28

    The epidemiology of invasive Haemophilus influenzae infections was evaluated in Ontario between 1989 and 2007 to assess the impact of the introduction of the conjugate H. influenzae serotype b (Hib) vaccine in the early 1990 s on Hib and non-Hib serotypes in both vaccinated and unvaccinated cohorts as well as the possibility of "strain replacement" with non-vaccine H. influenzae strains. Data were collected by the provincial Public Health Laboratories-Toronto, Ontario Agency for Health Protection and Promotion, which performed almost all serotyping on invasive (blood, CSF, other sterile sites) H. influenzae strains isolated in the province during the study period. Temporal trends for Hib, other typeable strains, and non-typeable H. influenzae were evaluated by Poisson regression, controlling for the specimen submissions. Prior to infant Hib vaccination, the most commonly observed serotype was serotype b (64.9%). Subsequently, 70.3%, 13.6%, and 9.4% of isolates were non-typeable, serotype f, and serotype b, respectively. Infant Hib vaccination resulted in a decrease in Hib incidence in all age groups (pooled IRR 0.432) and marked increases of non-typeable and serotype f H. influenzae in children aged <5 years (IRR 2.4 and 3.0, respectively). Vaccination against Hib has altered the epidemiology of invasive H. influenzae infections in Ontario. Prevention of invasive Hib disease was observed in both vaccinated and unvaccinated age groups. Invasive H. influenzae infection now commonly presents as sepsis due to non-typeable H. influenzae in older individuals. However, strain replacement of Hib with serotype f and non-typeable strains in children under 5 years was documented.

  18. Effects of nutritional supplementation with l-arginine on repair of injuries due to muscle strain: experimental study on rats☆

    PubMed Central

    Couto, Lauren Izabel Medeiros; Wuicik, William Luiz; Kuhn, Ivan; Capriotti, Juan Rodolfo Vilela; Repka, João Carlos

    2015-01-01

    Objective To evaluate the influence of oral supplementation with arginine on regeneration of injuries due to straining of the anterior tibial muscle of rats. Methods Twenty-four Wistar rats of weight 492.5 ± 50.45 g were used. Injuries were induced through straining the anterior tibial muscles. The rats were separated into three groups of eight rats each. In the untreated group (UTG), after induction of injuries, the rats were observed for 24 h. In the simulation group (SG) and the arginine group (AG) respectively, the rats received isotonic saline solution and arginine solution via direct gavage, over a seven-day period. At the end of the period, blood samples were collected for serum evaluations of creatine kinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and C-reactive protein (CRP). The right and left anterior tibial muscles were resected for histopathological evaluations on the muscle injuries, investigating edema, hemorrhage and disorganization or morphometric alteration of the muscle fibers. The tissue repair was investigated in terms of proliferation of adipose tissue, angiogenesis and collagen fibers. The ANOVA and Student's t methods were used and p ≤ 0.05 was taken to be statistically significant. Results In the serum evaluations, the AG showed lower CK assay values and higher AST values. In the histopathological evaluation, the UTG presented edema and hemorrhage compatible with injuries due to strain; the SG presented edema and hemorrhage with proliferation of adipose tissue and collagen fibers; and the AG presented not only the findings of the SG but also, especially, intense angiogenesis. Conclusion Oral supplementation with arginine did not cause any significant metabolic alterations that would contraindicate its use and it induced angiogenesis during the repair of muscles injured due to strain. PMID:26401505

  19. Marked increase in biofilm-derived rough pneumococcal variants and rifampin-resistant strains not due to hex gene mutations.

    PubMed

    McEllistrem, M Catherine; Scott, Jennifer R; Zuniga-Castillo, Jacobo; Khan, Saleem A

    2009-06-01

    Otitis, pneumonia, and meningitis are tissue-based pneumococcal infections that can be associated with biofilms. The emergence of phenotypic rough variants, also known as acapsular small-colony variants, is essential for pneumococcal biofilm formation. These rough variants can increase nearly 100-fold in biofilms over time and can arise through single nucleotide polymorphisms (SNPs), deletions, or tandem duplications in the first gene of the capsular operon, cps3D. We detected a 100-fold increase in rifampin-resistant (Rif(r)) mutants in biofilms compared to planktonic cultures using a nonvaccine serotype 3 strain, which is causing an increasing number of cases of otitis in the 7-valent pneumococcal conjugate vaccine era. Since both rough variants and Rif(r) strains can arise through SNPs, they could emerge due to alteration of the mismatch repair (MMR) system. The Hex system, a pneumococcal MMR system, repairs mismatches during replication and transformation. In this study, no mutations were detected in the hexAB gene sequences among several rough variants with unique mutations in the cps3D gene. Within a hexA null mutant grown in broth, we detected only a 17.5-fold increase in rough variants compared to the wild-type parental strain. Taken together, these data suggest that mutations in the hex genes and modulation of hexA activity are unlikely to account for the generation of biofilm-derived rough variants.

  20. TESTING AND ANALYSIS OF CAP CONCRETE STRESS AND STRAIN DUE TO SHRINKAGE, CREEP, AND EXPANSION FINAL REPORT

    SciTech Connect

    Guerrero, H.; Restivo, M.

    2011-08-01

    In-situ decommissioning of Reactors P- and R- at the Savannah River Site will require filling the reactor vessels with a special concrete based on materials such as magnesium phosphate, calcium aluminate or silica fume. Then the reactor vessels will be overlain with an 8 ft. thick layer of Ordinary Portland Cement (OPC) steel reinforced concrete, called the 'Cap Concrete'. The integrity of this protective layer must be assured to last for a sufficiently long period of time to avoid ingress of water into the reactor vessel and possible movement of radioactive contamination into the environment. During drying of this Cap Concrete however, shrinkage strains are set up in the concrete as a result of diffusion and evaporation of water from the top surface. This shrinkage varies with depth in the poured slab due to a non-uniform moisture distribution. This differential shrinkage results in restraint of the upper layers with larger shrinkage by lower layers with lesser displacements. Tensile stresses can develop at the surface from the strain gradients in the bulk slab, which can lead to surface cracking. Further, a mechanism called creep occurs during the curing period or early age produces strains under the action of restraining forces. To investigate the potential for surface cracking, an experimental and analytical program was started under TTQAP SRNL-RP-2009-01184. Slab sections made of Cap Concrete mixture were instrumented with embedded strain gages and relative humidity sensors and tested under controlled environmental conditions of 23 C and relative humidities (RH) of 40% and 80% over a period of 50 days. Calculation methods were also developed for predictions of stress development in the full-scale concrete placement over the reactor vessels. These methods were evaluated by simulating conditions for the test specimens and the calculation results compared to the experimental data. A closely similar test with strain gages was performed by Kim and Lee for a

  1. Efficacy of Ampicillin plus Ceftriaxone in Treatment of Experimental Endocarditis Due to Enterococcus faecalis Strains Highly Resistant to Aminoglycosides

    PubMed Central

    Gavaldà, Joan; Torres, Carmen; Tenorio, Carmen; López, Pedro; Zaragoza, Myriam; Capdevila, Josep A.; Almirante, Benito; Ruiz, Fernanda; Borrell, Nuria; Gomis, Xavier; Pigrau, Carles; Baquero, Fernando; Pahissa, Albert

    1999-01-01

    The purpose of this work was to evaluate the in vitro possibilities of ampicillin-ceftriaxone combinations for 10 Enterococcus faecalis strains with high-level resistance to aminoglycosides (HLRAg) and to assess the efficacy of ampicillin plus ceftriaxone, both administered with humanlike pharmacokinetics, for the treatment of experimental endocarditis due to HLRAg E. faecalis. A reduction of 1 to 4 dilutions in MICs of ampicillin was obtained when ampicillin was combined with a fixed subinhibitory ceftriaxone concentration of 4 μg/ml. This potentiating effect was also observed by the double disk method with all 10 strains. Time-kill studies performed with 1 and 2 μg of ampicillin alone per ml or in combination with 5, 10, 20, 40, and 60 μg of ceftriaxone per ml showed a ≥2 log10 reduction in CFU per milliliter with respect to ampicillin alone and to the initial inoculum for all 10 E. faecalis strains studied. This effect was obtained for seven strains with the combination of 2 μg of ampicillin per ml plus 10 μg of ceftriaxone per ml and for six strains with 5 μg of ceftriaxone per ml. Animals with catheter-induced endocarditis were infected intravenously with 108 CFU of E. faecalis V48 or 105 CFU of E. faecalis V45 and were treated for 3 days with humanlike pharmacokinetics of 2 g of ampicillin every 4 h, alone or combined with 2 g of ceftriaxone every 12 h. The levels in serum and the pharmacokinetic parameters of the humanlike pharmacokinetics of ampicillin or ceftriaxone in rabbits were similar to those found in humans treated with 2 g of ampicillin or ceftriaxone intravenously. Results of the therapy for experimental endocarditis caused by E. faecalis V48 or V45 showed that the residual bacterial titers in aortic valve vegetations were significantly lower in the animals treated with the combinations of ampicillin plus ceftriaxone than in those treated with ampicillin alone (P < 0.001). The combination of ampicillin and ceftriaxone showed in vitro and

  2. Temperature increase of Zircaloy-4 cladding tubes due to plastic heat dissipation during tensile tests at 0.1-10 s-1 strain rates

    NASA Astrophysics Data System (ADS)

    Hellouin de Menibus, Arthur; Auzoux, Quentin; Besson, Jacques; Crépin, Jérôme

    2014-11-01

    This study is focused on the impact of rapid Reactivity Initiated Accident (RIA) representative strain rates (about 1 s-1 NEA, 2010) on the behavior and fracture of unirradiated cold work stress relieved Zircaloy-4 cladding tubes. Uniaxial ring tests (HT) and plane strain ring tensile tests (PST) were performed in the 0.1-10 s-1 strain rate range, at 25 °C. The local temperature increase due to plastic dissipation was measured with a high-speed infrared camera. Limited temperature increases were measured at 0.1 s-1 strain rate. Limited but not strongly localized temperature increases were measured at 1 s-1. Large temperature increase were measured at 5 and 10 s-1 (142 °C at 5 s-1 strain rate in HT tests). The local temperature increase induced heterogeneous temperature fields, which enhanced strain localization and resulted in a reduction of the plastic elongation at fracture.

  3. In vitro anti-Helicobacter pylori activity of the probiotic strain Bacillus subtilis 3 is due to secretion of antibiotics.

    PubMed

    Pinchuk, I V; Bressollier, P; Verneuil, B; Fenet, B; Sorokulova, I B; Mégraud, F; Urdaci, M C

    2001-11-01

    A limited number of antibiotics can be used against Helicobacter pylori infection, and resistance jeopardizes the success of treatment. Therefore, a search for new agents is warranted. The use of probiotics to enhance gastrointestinal health has been proposed for many years, but the scientific basis of the prophylactic and therapeutic actions of probiotics has not yet been clearly delineated. Probiotic strain Bacillus subtilis 3, whose safety has previously been demonstrated, is known to have antagonistic properties against species of the family Enterobacteriaceae. In the present study, it was also found to inhibit H. pylori. The anti-H. pylori activity present in the cell-free supernatant was not related to pH or organic acid concentration. It was heat stable and protease insensitive. At least two antibiotics, detected by thin-layer chromatography (R(f) values, 0.47 and 0.85, respectively) and confirmed by high-performance liquid chromatographic analysis, were found to be responsible for this anti-H. pylori activity. All H. pylori strains tested were sensitive to both compounds. One of these compounds was identified as amicoumacin A, an antibiotic with anti-inflammatory properties. MICs for H. pylori determined in solid and liquid media ranged between 1.7 and 6.8 microg/ml and 0.75 and 2.5 microg/ml, respectively. The underestimation of MICs determined in solid medium may be due to physicochemical instability of the antibiotic under these test conditions. An additive effect between amicoumacin A and the nonamicoumacin antibiotic against H. pylori was demonstrated.

  4. In Vitro Anti-Helicobacter pylori Activity of the Probiotic Strain Bacillus subtilis 3 Is Due to Secretion of Antibiotics

    PubMed Central

    Pinchuk, Irina V.; Bressollier, Philippe; Verneuil, Bernard; Fenet, Bernard; Sorokulova, Irina B.; Mégraud, Francis; Urdaci, Maria C.

    2001-01-01

    A limited number of antibiotics can be used against Helicobacter pylori infection, and resistance jeopardizes the success of treatment. Therefore, a search for new agents is warranted. The use of probiotics to enhance gastrointestinal health has been proposed for many years, but the scientific basis of the prophylactic and therapeutic actions of probiotics has not yet been clearly delineated. Probiotic strain Bacillus subtilis 3, whose safety has previously been demonstrated, is known to have antagonistic properties against species of the family Enterobacteriaceae. In the present study, it was also found to inhibit H. pylori. The anti-H. pylori activity present in the cell-free supernatant was not related to pH or organic acid concentration. It was heat stable and protease insensitive. At least two antibiotics, detected by thin-layer chromatography (Rf values, 0.47 and 0.85, respectively) and confirmed by high-performance liquid chromatographic analysis, were found to be responsible for this anti-H. pylori activity. All H. pylori strains tested were sensitive to both compounds. One of these compounds was identified as amicoumacin A, an antibiotic with anti-inflammatory properties. MICs for H. pylori determined in solid and liquid media ranged between 1.7 and 6.8 μg/ml and 0.75 and 2.5 μg/ml, respectively. The underestimation of MICs determined in solid medium may be due to physicochemical instability of the antibiotic under these test conditions. An additive effect between amicoumacin A and the nonamicoumacin antibiotic against H. pylori was demonstrated. PMID:11600371

  5. Hypermotility in Clostridium perfringens strain SM101 is due to spontaneous mutations in genes linked to cell division.

    PubMed

    Liu, Hualan; McCord, Kristin D; Howarth, Jonathon; Popham, David L; Jensen, Roderick V; Melville, Stephen B

    2014-07-01

    Clostridium perfringens is a Gram-positive anaerobic pathogen of humans and animals. Although they lack flagella, C. perfringens bacteria can still migrate across surfaces using a type of gliding motility that involves the formation of filaments of bacteria lined up in an end-to-end conformation. In strain SM101, hypermotile variants are often found arising from the edges of colonies on agar plates. Hypermotile cells are longer than wild-type cells, and video microscopy of their gliding motility suggests that they form long, thin filaments that move rapidly away from a colony, analogously to swarmer cells in bacteria with flagella. To identify the cause(s) of the hypermotility phenotype, the genome sequences of normal strains and their direct hypermotile derivatives were determined and compared. Strains SM124 and SM127, hypermotile derivatives of strains SM101 and SM102, respectively, contained 10 and 6 single nucleotide polymorphisms (SNPs) relative to their parent strains. While SNPs were located in different genes in the two sets of strains, one feature in common was mutations in cell division genes, an ftsI homolog in strain SM124 (CPR_1831) and a minE homolog in strain SM127 (CPR_2104). Complementation of these mutations with wild-type copies of each gene restored the normal motility phenotype. A model explaining the principles underlying the hypermotility phenotype is presented.

  6. Strain changes on the cortical shell of vertebral bodies due to spine ageing: a parametric study using a finite element model evaluated by strain measurements.

    PubMed

    Lu, Yongtao; Rosenau, Eike; Paetzold, Helge; Klein, Anke; Püschel, Klaus; Morlock, Michael M; Huber, Gerd

    2013-12-01

    The probability of fractures of the cortical shell of vertebral bodies increases as ageing progresses. Ageing involves all the spinal component changes. However, the effect of the spinal component ageing on the fracture risk of the cortical shell remains poorly understood. In this study, the influence of the ageing of the spinal components on cortical shell strain was investigated. A lumbar spinal specimen (L3-L5) was mechanically tested under a quasi-static axial compressive load. Clinical computed tomography images of the same specimen were used to create a corresponding finite element model. The material properties were determined by calibrating the finite element model using the L4 cortical shell strains of the anterior centre measurement site. The remaining experiment data (axial displacement, the intra-discal pressures, L4 cortical shell strain on the lateral measurement site) were used to evaluate the model. The individual ageing process of the six spinal components (cortical shell, cancellous bone, bony endplate, posterior elements, nucleus pulposus and annulus matrix) was simulated by changing their Young's moduli and Poisson's ratios, and the effect on cortical shell strain was investigated. Results show that the cortical shell strain is more sensitive to the ageing of the cortical shell and the cancellous bone than to the ageing of the nucleus pulposus, the annulus matrix, and the bony endplates and of the posterior elements. The results can help the clinicians focus on the aspects that mainly influence the vertebral cortex fracture risk factor.

  7. Local strain evolution due to athermal γ→ε martensitic transformation in biomedical CoCrMo alloys.

    PubMed

    Yamanaka, Kenta; Mori, Manami; Koizumi, Yuichiro; Chiba, Akihiko

    2014-04-01

    Locally developed strains caused by athermal γ face-centered cubic (fcc)→ε hexagonal close-packed (hcp) martensitic transformation were investigated for the γ matrix of Ni-free Co-29Cr-6Mo (wt%) alloys prepared with or without added nitrogen. Electron-backscatter-diffraction-(EBSD)-based strain analysis revealed that in addition to ε-martensite interiors, the N-free alloy that had a duplex microstructure consisting of the γ matrix and athermal ε-martensite plates showed larger magnitudes of both elastic and plastic strains in the γ phase matrix than the N-doped counterpart that did not have a ε-martensite phase. Transmission electron microscopy (TEM) results indicated that the ε-martensite microplates were aggregates of thin ε-layers, which were formed by three different {111}γ〈112¯〉γ Shockley partial dislocations in accordance with a previously proposed mechanism (Putaux and Chevalier, 1996) that canceled the shear strains of the individual variants. The plastic strains are believed to have originated from the martensitic transformation itself, and the activity of dislocations is believed to be the origin of the transformation. We have revealed that the elastic strains in the γ matrix originate from interactions among the ε-martensite phase, extended dislocations, and/or thin ε-layers. The dislocations highly dissociated into stacking faults, making stress relaxation at intersections difficult and further introducing local strain evolution.

  8. Prediction of plastic strains in ultra-high molecular weight polyethylene due to microscopic asperity interactions during sliding wear.

    PubMed

    McNie, C; Barton, D C; Stone, M H; Fisher, J

    1998-01-01

    Studies of explanted femoral heads have shown that scratches caused by bone cement, bone or metallic particles are present on the rubbing surface. This damage has been cited as a cause of increased wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and it is known that the particulate wear debris produced leads to osteolysis. A series of explanted Charnley femoral heads have been surface characterized using a Talysurf 6 profilometer and found to have scratches with lip heights in the size range 0.1-3.25 microns with an average height of 1 micron giving an average aspect ratio (defined as height/half-width) of 0.1. These geometries were incorporated into a finite element model of a stainless steel asperity sliding over UHMWPE under conditions similar to those in an artificial hip system. It was found that as the aspect ratio of the asperity lip increased, the plastic strains both on and below the surface of the UHMWPE increased non-linearly, but that the magnitude of the strain was independent of the asperity height. The asperity aspect ratio was also found to affect the position of the maximum sub-surface strain, as the asperity aspect ratio was increased the maximum strain rose to the surface. The high plastic strains predicted offer an explanation for the highly elevated wear rates in scratched counterface tests and the aspect ratio of scratch lips is therefore a critical determinant of plastic strain.

  9. Common skin infection due to Panton-Valentine leucocidin-producing Staphylococcus aureus strains in asylum seekers from Eritrea: a genome-based investigation of a suspected outbreak.

    PubMed

    Jaton, L; Pillonel, T; Jaton, K; Dory, E; Prod'hom, G; Blanc, D S; Tissot, F; Bodenmann, P; Greub, G

    2016-08-01

    Since late 2014, multiple cases of abscesses and boils due to methicillin-susceptible Staphylococcus aureus (MSSA) expressing the Panton-Valentine leucocidin (PVL) were observed in Eritrean asylum seekers in Lausanne, Switzerland. Strains isolated from infected Eritrean and non-Eritrean patients were compared by whole genome sequencing to determine whether these numerous cases result from an outbreak. The genome of S. aureus PVL-producing strains were sequenced and compared. Clinical and epidemiological characteristics of patients infected by PVL-producing strains were investigated. This work reports 15 cases of infections due to PVL-producing strains affecting mostly asylum seekers (n = 10), people working with refugees and/or exposed to Africans (n = 3). Most infections were due to closely related strains of CC152 (n = 8) and CC15 (n = 3), two distantly related (>34 000 core single nucleotide polymorphisms) clonal complexes. An epidemiological link between the 15 cases could be ruled out by whole genome sequencing (33 to 172 core single nucleotide polymorphisms between the different strains of a given complex). Altogether, these results reflect the probable high incidence of CC15 and CC152 PVL-producing strains in eastern Africa. Clinicians facing unusual skin infections in African refugees (or in any person returning from this region of high endemicity) should consider S. aureus PVL-producer before suspecting rare infections such as leishmaniasis or rickettsiosis. Clinicians should also remember that PVL are frequently expressed by MSSA in some regions of the world and that antibiotics that are efficient on toxin expression, such as clindamycin, represent the best therapeutic option.

  10. Finite element modelling predicts changes in joint shape and cell behaviour due to loss of muscle strain in jaw development

    PubMed Central

    Brunt, Lucy H.; Norton, Joanna L.; Bright, Jen A.; Rayfield, Emily J.; Hammond, Chrissy L.

    2015-01-01

    Abnormal joint morphogenesis is linked to clinical conditions such as Developmental Dysplasia of the Hip (DDH) and to osteoarthritis (OA). Muscle activity is known to be important during the developmental process of joint morphogenesis. However, less is known about how this mechanical stimulus affects the behaviour of joint cells to generate altered morphology. Using zebrafish, in which we can image all joint musculoskeletal tissues at high resolution, we show that removal of muscle activity through anaesthetisation or genetic manipulation causes a change to the shape of the joint between the Meckel's cartilage and Palatoquadrate (the jaw joint), such that the joint develops asymmetrically leading to an overlap of the cartilage elements on the medial side which inhibits normal joint function. We identify the time during which muscle activity is critical to produce a normal joint. Using Finite Element Analysis (FEA), to model the strains exerted by muscle on the skeletal elements, we identify that minimum principal strains are located at the medial region of the joint and interzone during mouth opening. Then, by studying the cells immediately proximal to the joint, we demonstrate that biomechanical strain regulates cell orientation within the developing joint, such that when muscle-induced strain is removed, cells on the medial side of the joint notably change their orientation. Together, these data show that biomechanical forces are required to establish symmetry in the joint during development. PMID:26253758

  11. Phase shift of TE and TM modes in an optical fiber due to axial strain (exact solution)

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1992-01-01

    Axial strain may be determined by monitoring the phase shift of modes of a variety of optical fiber sensors. In this paper, the exact solution of a circular optical fiber is used to calculate the phase shift of the TE and TM modes. Whenever an optical fiber is stressed, the optical path length, the index of refraction, and the propagation constants of each fiber mode change. In consequence, the modal phase term, beta(ln)z, of the fields is shifted by an amount Delta phi. In certain cases, it is desirable to control the phase shift term in order to make the fiber either more or less sensitive to certain kinds of strain. It is shown that it can be accomplished by choosing appropriate fiber parameters.

  12. Functional MRI for characterization of renal perfusion impairment and edema formation due to acute kidney injury in different mouse strains

    PubMed Central

    Chen, Rongjun; Gutberlet, Marcel; Jang, Mi-Sun; Meier, Martin; Mengel, Michael; Hartung, Dagmar; Wacker, Frank; Rong, Song; Hueper, Katja

    2017-01-01

    Purpose The purpose was to characterize acute kidney injury (AKI) in C57BL/6 (B6)- and 129/Sv (Sv)-mice by noninvasive measurement of renal perfusion and tissue edema using functional MRI. Methods Different severities of AKI were induced in B6- and Sv-mice by renal ischemia reperfusion injury (IRI). Unilateral clamping of the renal pedicle for 35 min (moderate AKI) or 45 min (severe AKI) was done. MRI (7-Tesla) was performed 1, 7 and 28 days after surgery using a flow alternating inversion recovery (FAIR) arterial spin labeling (ASL) sequence. Maps of perfusion and T1-relaxation time were calculated. Relative MRI-parameters of the IRI kidney compared to the contralateral not-clipped kidney were compared between AKI severities and between mouse strains using unpaired t-tests. In addition, fibrosis was assessed by Masson Trichrome and collagen IV staining. Results After moderate AKI relative perfusion impairment was significantly higher in B6- than in Sv-mice at d7 (55±7% vs. 82±8%, p<0.05) and d28 (76±7% vs. 102±3%, p<0.01). T1-values increased in the early phase after AKI in both mouse strains. T1-increase was more severe after prolonged ischemia times of 45 min compared to 35 min in both mouse strains, measured in the renal cortex and outer stripe of outer medulla. Kidney volume loss (compared to the contralateral kidney) occurred already after 7 days but proceeded markedly towards 4 weeks in severe AKI. Early renal perfusion impairment was predictive for later kidney volume loss. The progression to chronic kidney disease (CKD) in the severe AKI model was similar in both mouse strains as revealed by histology. Conclusion Quantification of renal perfusion and tissue edema by functional MRI allows characterization of strain differences upon AKI. Renal perfusion impairment was stronger in B6- compared to Sv-animals following moderate AKI. Prolonged ischemia times were associated with more severe perfusion impairment and edema formation in the early phase and

  13. The 1998 Senegal Epidemic of Meningitis Was Due to the Clonal Expansion of A:4:P1.9, Clone III-1, Sequence Type 5 Neisseria meningitidis Strains

    PubMed Central

    Nicolas, Pierre; Raphenon, Georges; Guibourdenche, Martine; Decousset, Laurent; Stor, Richard; Gaye, Abou Beckr

    2000-01-01

    Between January and April 1998, a meningitis outbreak due to serogroup A meningococcus took place in Senegal. The outbreak began in Gandiaye, 165 km to the east of Dakar, and progressed towards the towns of Gossas, Niakkhar, Guinguineo, Fatik, Foundiougne, Dioffior, Sokone, Kaolack, and Nioro. At the same time, the outbreak reached regions of Kaffrine, Koungheul, and Tambacounda in the east of Senegal. A total of 1,350 cases and 200 deaths were reported. The WHO Collaborating Center in Marseilles received 24 strains for analysis. All were serogroup A Neisseria meningitidis, type 4 and subtype P1.9. Multilocus enzyme electrophoresis, performed by Institut Pasteur Paris, showed that the strains belonged to clone III-1. DNA restriction fragments generated by endonuclease BglII and analyzed by pulsed-field gel electrophoresis showed 24 indistinguishable fingerprint patterns similar to those of meningococcus strains isolated from African outbreaks since 1988. Three strains were studied by multilocus sequence typing (MLST) with seven loci. The comparison between sequences and existing alleles on the MLST website (http://mlst.zoo.ox.ac.uk) allowed us to assign these strains to sequence type 5 (ST5), as their sequences were identical to the consensus at seven loci. All 24 strains were susceptible to penicillin, amoxicillin, chloramphenicol, and rifampin. Subgroup III is finishing its spread towards west of the meningitis belt of Africa. To our knowledge, this is the first time subgroup III, and more precisely ST5, strains are reported as being responsible for a meningitis outbreak in Senegal. PMID:10618087

  14. Is the effect of job strain on myocardial infarction risk due to interaction between high psychological demands and low decision latitude? Results from Stockholm Heart Epidemiology Program (SHEEP).

    PubMed

    Hallqvist, J; Diderichsen, F; Theorell, T; Reuterwall, C; Ahlbom, A

    1998-06-01

    The objectives are to examine if the excess risk of myocardial infarction from exposure to job strain is due to interaction between high demands and low control and to analyse what role such an interaction has regarding socioeconomic differences in risk of myocardial infarction. The material is a population-based case-referent study having incident first events of myocardial infarction as outcome (SHEEP: Stockholm Heart Epidemiology Program). The analysis is restricted to males 45-64 yr of age with a more detailed analysis confined to those still working at inclusion. In total, 1047 cases and 1450 referents were included in the analysis. Exposure categories of job strain were formed from self reported questionnaire information. The results show that high demands and low decision latitude interact with a synergy index of 7.5 (95% C.I.: 1.8-30.6) providing empirical support for the core mechanism of the job strain model. Manual workers are more susceptible when exposed to job strain and its components and this increased susceptibility explains about 25-50% of the relative excess risk among manual workers. Low decision latitude may also, as a causal link, explain about 30% of the socioeconomic difference in risk of myocardial infarction. The distinction between the interaction and the causal link mechanisms identifies new etiologic questions and intervention alternatives. The specific causes of the increased susceptibility among manual workers to job strain and its components seem to be an interesting and important research question.

  15. Use of multiple molecular subtyping techniques to investigate a Legionnaires' disease outbreak due to identical strains at two tourist lodges.

    PubMed Central

    Mamolen, M; Breiman, R F; Barbaree, J M; Gunn, R A; Stone, K M; Spika, J S; Dennis, D T; Mao, S H; Vogt, R L

    1993-01-01

    A multistate outbreak of Legionnaires' disease occurred among nine tour groups of senior citizens returning from stays at one of two lodges in a Vermont resort in October 1987. Interviews and serologic studies of 383 (85%) of the tour members revealed 17 individuals (attack rate, 4.4%) with radiologically documented pneumonia and laboratory evidence of legionellosis. A survey of tour groups staying at four nearby lodges and of Vermont-area medical facilities revealed no additional cases. Environmental investigation of common tour stops revealed no likely aerosol source of Legionella infection outside the lodges. Legionella pneumophila serogroup 1 was isolated from water sources at both implicated lodges, and the monoclonal antibody subtype matched those of the isolates from six patients from whom clinical isolates were obtained. The cultures reacted with monoclonal antibodies MAB1, MAB2, 33G2, and 144C2 to yield a 1,2,5,7 or a Benidorm 030E pattern. The strains were also identical by alloenzyme electrophoresis and DNA ribotyping techniques. The epidemiologic and laboratory data suggest that concurrent outbreaks occurred following exposures to the same L. pneumophila serogroup 1 strain at two separate lodges. Multiple molecular subtyping techniques can provide essential information for epidemiologic investigations of Legionnaires' disease. PMID:8253953

  16. True polar wander of a quasi-fluid planet with a fossil shape: Effect of strain energy due to tidal deformation

    NASA Astrophysics Data System (ADS)

    Harada, Y.

    2011-12-01

    In the present study, temporal variation of a paleo-pole position due to TPW is formulated and calculated based on strain energy in a previous study. Especially, quasi-fluid approximation is suitable to deal with large-scale and long-term variation of a paleo-pole position. Thus, an orientation of a paleo-rotation axis in each time step is estimated in here by following conventional formulation with the quasi-fluid approximation for TPW, and simultaneously by taking total energy minimization into account. In practice, this procedure is physically same as to incorporate elastic torque due to tidal deformation of a lithosphere into the Liouville equation including the quasi-fluid approximation. In this study, like the previous one, only one symmetric surface load is regarded as a driving force of TPW for convenience sake. In this calculation, variable parameters are defined as follows: a location of emplacement, duration of formation, and maximum of intensity of a load. The result with strain energy is compared with that without strain energy. As a result, the case with the strain energy indicates different characteristics from that without the strain energy in the following points. First, the paleo-poles under steady states are different each other in the cases for same parameters. These results are not consistent even with the previous results concerning just the final condition. Second, also in the cases for same parameters, time scales when the paleo-poles reach the static limits are different. These results demonstrate the fact that strain energy within a lithosphere effectively weakens influence of a load on TPW. Although this kind of influence has already been pointed out by the previous results just in the cases of the steady states, the present results further revealed similar effect also on a characteristic time scale of TPW. Strictly speaking, however, it is impossible to estimate this exact time scale only by reducing an effective size of a load. This is

  17. Antibiotic Resistance in Pseudomonas aeruginosa Strains with Increased Mutation Frequency Due to Inactivation of the DNA Oxidative Repair System▿

    PubMed Central

    Mandsberg, L. F.; Ciofu, O.; Kirkby, N.; Christiansen, L. E.; Poulsen, H. E.; Høiby, N.

    2009-01-01

    The chronic Pseudomonas aeruginosa infection of the lungs of cystic fibrosis (CF) patients is characterized by the biofilm mode of growth and chronic inflammation dominated by polymorphonuclear leukocytes (PMNs). A high percentage of P. aeruginosa strains show high frequencies of mutations (hypermutators [HP]). P. aeruginosa is exposed to oxygen radicals, both those generated by its own metabolism and especially those released by a large number of PMNs in response to the chronic CF lung infection. Our work therefore focused on the role of the DNA oxidative repair system in the development of HP and antibiotic resistance. We have constructed and characterized mutT, mutY, and mutM mutants in P. aeruginosa strain PAO1. The mutT and mutY mutants showed 28- and 7.5-fold increases in mutation frequencies, respectively, over that for PAO1. These mutators had more oxidative DNA damage (higher levels of 7,8-dihydro-8-oxodeoxyguanosine) than PAO1 after exposure to PMNs, and they developed resistance to antibiotics more frequently. The mechanisms of resistance were increased β-lactamase production and overexpression of the MexCD-OprJ efflux-pump. Mutations in either the mutT or the mutY gene were found in resistant HP clinical isolates from patients with CF, and complementation with wild-type genes reverted the phenotype. In conclusion, oxidative stress might be involved in the development of resistance to antibiotics. We therefore suggest the possible use of antioxidants for CF patients to prevent the development of antibiotic resistance. PMID:19332676

  18. Diarrhea, bacteremia and multiorgan dysfunction due to an extraintestinal pathogenic Escherichia coli strain with enteropathogenic E. coli genes.

    PubMed

    Kessler, Robert; Nisa, Shahista; Hazen, Tracy H; Horneman, Amy; Amoroso, Anthony; Rasko, David A; Donnenberg, Michael S

    2015-11-01

    A 55-year-old man with well-controlled HIV had severe diarrhea for 3 weeks and developed multiorgan dysfunction and bacteremia due to Escherichia coli. The genome of the patient's isolate had features characteristic of extraintestinal pathogenic E. coli and genes distantly related to those defining enteropathogenic E. coli.

  19. An international invasive meningococcal disease outbreak due to a novel and rapidly expanding serogroup W strain, Scotland and Sweden, July to August 2015

    PubMed Central

    Lucidarme, Jay; Scott, Kevin J; Ure, Roisin; Smith, Andrew; Lindsay, Diane; Stenmark, Bianca; Jacobsson, Susanne; Fredlund, Hans; Cameron, J Claire; Smith-Palmer, Alison; McMenamin, Jim; Gray, Steve J; Campbell, Helen; Ladhani, Shamez; Findlow, Jamie; Mölling, Paula; Borrow, Ray

    2016-01-01

    The 23rd World Scout Jamboree in 2015 took place in Japan and included over 33,000 scouts from 162 countries. Within nine days of the meeting ending, six cases of laboratory-confirmed invasive serogroup W meningococcal disease occurred among scouts and their close contacts in Scotland and Sweden. The isolates responsible were identical to one-another by routine typing and, where known (4 isolates), belonged to the ST-11 clonal complex (cc11) which is associated with large outbreaks and high case fatality rates. Recent studies have demonstrated the need for high-resolution genomic typing schemes to assign serogroup W cc11 isolates to several distinct strains circulating globally over the past two decades. Here we used such schemes to confirm that the Jamboree-associated cases constituted a genuine outbreak and that this was due to a novel and rapidly expanding strain descended from the strain that has recently expanded in South America and the United Kingdom. We also identify the genetic differences that define the novel strain including four point mutations and three putative recombination events involving the horizontal exchange of 17, six and two genes, respectively. Noteworthy outcomes of these changes were antigenic shifts and the disruption of a transcriptional regulator. PMID:27918265

  20. Rat strain differences in levels and effects of chronic inflammation due to intratracheal instillation of quartz on lung tumorigenesis induced by DHPN.

    PubMed

    Nakano, Yuko; Yokohira, Masanao; Hashimoto, Nozomi; Yamakawa, Keiko; Kishi, Sosuke; Ninomiya, Fumiko; Kanie, Shohei; Saoo, Kousuke; Imaida, Katsumi

    2014-10-01

    Chronic inflammatory effects of single intratracheal instillation (i.t.) of quartz on rat lung tumorigenesis were examined using 4 different animal models. At first, in order to determine an appropriate dose of quartz i.t. to promote lung tumorigenesis, F344 male rats were administrated single 0, 0.5, 1, 2 or 4 mg quartz/rat after initiation by N-bis(2-hydroxypropyl) nitrosamine (DHPN). Further studies were performed to examine strain differences of the effects of chronic inflammation caused by quartz i.t. in 3 strains of rat, i.e. F344, Wistar-Hannover and SD. Each was instilled with 2mg quartz/rat after DHPN administration and sacrificed in week 24. In addition, strain differences in generation of inflammation were determined at days 1 and 28. Finally, for determination of long-term effects period, F344 and Wistar-Hannover rats were similarly treated, but the experiment was terminated at week 52. In F344 rats, the tumor areas in DHPN treated groups showed a tendency to increase along with the dose of quartz. F344 rats demonstrated the highest and Wistar-Hannover rats the lowest sensitivity to quartz in acute and chronic phases in the 3 strains. In 52 week, in F344 rats, the multiplicity of tumors and the serum concentration of IL-6 in the group treated with DHPN and quartz were significantly increased. The present experiments indicated that chronic inflammation due to quartz instillation exerted promoting effects on lung carcinogenesis in F344, SD and Wistar-Hannover rats. The strain differences in tumor promotion appeared to correlate with inflammatory reactions to quartz and increase of IL-6.

  1. Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains

    PubMed Central

    Liu, Chao; Pan, Fei; Guo, Jun; Yan, Weifeng; Jin, Yi; Liu, Changting; Qin, Long; Fang, Xiangqun

    2016-01-01

    Background: Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare. Methods: A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined. Results: The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like. The main type was blaOXA-114q. The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate. Conclusion: Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes. PMID:27242678

  2. Gd5(Si,Ge)4 thin film displaying large magnetocaloric and strain effects due to magnetostructural transition

    NASA Astrophysics Data System (ADS)

    Hadimani, Ravi L.; Silva, Joao H. B.; Pereira, Andre M.; Schlagel, Devo L.; Lograsso, Thomas A.; Ren, Yang; Zhang, Xiaoyi; Jiles, David C.; Araújo, Joao P.

    2015-01-01

    Magnetic refrigeration based on the magnetocaloric effect is one of the best alternatives to compete with vapor-compression technology. Despite being already in its technology transfer stage, there is still room for optimization, namely, on the magnetic responses of the magnetocaloric material. In parallel, the demand for different magnetostrictive materials has been greatly enhanced due to the wide and innovative range of technologies that emerged in the last years (from structural evaluation to straintronics fields). In particular, the Gd5(SixGe1-x)4 compounds are a family of well-known alloys that present both giant magnetocaloric and colossal magnetostriction effects. Despite their remarkable properties, very few reports have been dedicated to the nanostructuring of these materials: here, we report a ˜800 nm Gd5Si2.7Ge1.3 thin film. The magnetic and structural investigation revealed that the film undergoes a first order magnetostructural transition and as a consequence exhibits large magnetocaloric effect (-ΔSmMAX ˜ 8.83 J kg-1 K-1, ΔH = 5T) and giant thermal expansion (12000 p.p.m). The thin film presents a broader magnetic response in comparison with the bulk compound, which results in a beneficial magnetic hysteresis reduction. The ΔSmMAX exhibited by the Gd5(Si,Ge)4 thin film makes it a promising candidate for micro/nano magnetic refrigeration area.

  3. The first clinical case due to AP92 like strain of Crimean-Congo Hemorrhagic Fever virus and a field survey

    PubMed Central

    2009-01-01

    Background Crimean-Congo Hemorrhagic Fever (CCHF) is a fatal infection, but no clinical case due to AP92 strain was reported. We described the first clinical case due to AP92 like CCHFV. Methods A case infected by a AP92 like CCHFV was detected in Balkanian part of Turkey. Diagnosis was confirmed by RT-PCR and sequencing. A human serologic and tick survey studies were performed in the region, where the case detected. Results Thirty eight individuals out of 741 were found to be anti CCHFV IgM positive. The attack rate for overall CCHFV was calculated as 5.2%. In univariate analyses, CCHFV IgM positivity was found to be associated with the age (p < 0.001), male gender (p = 0.001), agricultural activity (p = 0.036), and history of tick bite (p = 0.014). In multivariate analysis, older age (OR: 1.03, CI:1.01–1.05, p < 0.001), male gender were found to be the risk factors (OR: 2.5, CI:1.15–5.63, p = 0.020) for CCHFV infection. Conclusion This is the first human case with AP92 like CCHFV infection. Furthermore, this is the first report of AP92 like strain in Turkey. In the region, elderly males carry the highest risk for CCHFV infection. PMID:19515251

  4. Enhancement of UV Light Sensitivity of a Vibrio parahaemolyticus O3:K6 Pandemic Strain Due to Natural Lysogenization by a Telomeric Phage▿

    PubMed Central

    Zabala, Beatriz; García, Katherine; Espejo, Romilio T.

    2009-01-01

    The Vibrio parahaemolyticus O3:K6 pandemic clonal strain was first observed in southern Chile in 2004 and has since caused approximately 8,000 seafood-related diarrhea cases in this region. The massive proliferation of the original clonal population offers a unique opportunity to study the evolution of a bacterial pathogen in its natural environment by detection and characterization of emerging bacterial variants. Here, we describe a group of pandemic variants characterized by the presence of a 42-kb extrachromosomal DNA that can be recovered by alkaline extraction. Upon treatment with mitomycin C, these variants lyse with production of a myovirus containing DNA of equal size to the plasmid but which cannot be recovered by alkaline extraction. Plasmid and phage DNAs show similar restriction patterns corresponding to enzyme sites in a circular permutation. Sequenced regions showed 81 to 99% nucleotide similarity to bacteriophage VHML of Vibrio harveyi. Altogether these observations indicate that the 42-kb plasmid corresponds to a prophage, consisting of a linear DNA with terminal hairpins of a telomeric temperate phage with a linear genome. Bacteria containing the prophage were 7 to 15 times more sensitive to UV radiation, likely due to phage induction by UV irradiation as plasmid curing restored the original sensitivity. The enhanced UV sensitivity could have a significant role in reducing the survival and propagation capability of the V. parahaemolyticus pandemic strain in the ocean. PMID:19151181

  5. Efficacies of colistin and tigecycline in mice with experimental pneumonia due to NDM-1-producing strains of Klebsiella pneumoniae and Escherichia coli.

    PubMed

    Docobo-Pérez, Fernando; Nordmann, Patrice; Domínguez-Herrera, Juan; López-Rojas, Rafael; Smani, Younes; Poirel, Laurent; Pachón, Jerónimo

    2012-03-01

    New Delhi metallo-β-lactamase-1 (NDM-1)-producing Enterobacteriaceae have emerged as a global threat. The aim of this study was to assess the efficacies of colistin and tigecycline in an experimental model of pneumonia caused by NDM-1-producing Escherichia coli and Klebsiella pneumoniae. The susceptibilities of K. pneumoniae NDM, E. coli NDM and K. pneumoniae ATCC 29665 were determined using the broth microdilution technique. The pharmacokinetics of colistin and tigecycline in an experimental model of pneumonia were performed using immunocompetent C57BL/6 mice. Mice were treated with colistin (60 mg/kg/day) or tigecycline (10 mg/kg/day). Mortality, bacteraemia and lung bacterial concentrations were recorded. The strains were susceptible to colistin and tigecycline. The ratio of area under the concentration-time curve/minimum inhibitory concentration (AUC/MIC) for colistin was 158.5 (all three strains) and that for tigecycline was 18.5 (K. pneumoniae NDM) and 37 (K. pneumoniae ATCC 29665 and E. coli NDM). In vivo, colistin decreased bacterial lung concentrations of K. pneumoniae NDM and K. pneumoniae ATCC 29665 by 1.16 log colony-forming units (CFU)/g and 2.23 logCFU/g, respectively, compared with controls (not significant). Tigecycline reduced K. pneumoniae NDM and K. pneumoniae ATCC 29665 load by 2.67 logCFU/g and 4.62 logCFU/g (P<0.05). Colistin and tigecycline decreased lung concentrations of E. coli NDM by 2.27 logCFU/g and 4.15 logCFU/g (P<0.05), respectively, compared with controls, and was more active than colistin (P<0.05). In conclusion, these results suggest that colistin is inappropriate for treating pneumonia due to NDM-1-producing K. pneumoniae and its efficacy was suboptimal against NDM-1-producing E. coli. A high tigecycline dose was efficacious for treating experimental pneumonia due to NDM-1-producing E. coli and K. pneumoniae.

  6. New aspects about reduced LCF-life time of spherical ductile cast iron due to dynamic strain aging at intermediate temperatures

    NASA Astrophysics Data System (ADS)

    Mouri, Hayato; Wunderlich, Wilfried; Hayashi, Morihito

    2009-06-01

    Spherical ductile cast iron (FCD400) is widely used as container material in nuclear energy processing line due to its superior mechanical properties and low price. Fatigue properties in low cycle fatigue (LCF) can be described well by the Manson-Coffin-Basquin's rule. However, at intermediate temperature range between 453 and 723 K the elongation-temperature-diagram shows a significantly 20-10% reduced elongation and an increase in yield stress in tensile test experiments. These non-linear deviations and the phenomenon of less ductility at intermediate temperatures are known for a long time [1] [K. Chijiiwa, M. Hayashi, Mechanical properties of ductile cast iron at temperature in the region of room temperature to liquid, Imono 51 (7) (2004) 395-400]. But the following explanation is presented for the first time. In the same temperature range as the reduced fatigue life time dynamic strain ageing (DSA) also known as Portevin-le-Chartelier effect with the formation of visible serrations occurs. Both phenomena are explained by interaction effects between carbon diffusion and dislocation velocity which have at this temperature the same order of magnitude. However, this phenomenon shows interesting behavior at intermediate temperature range. During the low cycle fatigue test, DSA phenomenon disappeared, but mechanical properties show clear evidence of DSA phenomenon. Therefore, the purpose of this paper is to study the correlation of DSA occurrence, LCF and mechanical properties.

  7. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the bla NDM-1 element and clonal spread of progenitor resistant strains.

    PubMed

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the bla NDM-1 element, and the rest of 24 CRE strains were all positive for bla KPC-2. The 21 bla NDM-1-borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of bla NDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to bla NDM-1, several CRE strains were also found to harbor the bla KPC-2, bla VIM-1, and bla IMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas.

  8. [Efficacy of levofloxacin, lomefloxacin and moxifloxacin vs. other fluoroquinolones in experimental plague due to FI+ and FI- strains of Yersinia pestis in Albino mice].

    PubMed

    Ryzhko, I V; Tsuraeva, R I; Anisimov, B I; Trishina, A V

    2009-01-01

    Activity of levofloxacin, lomefloxacin and moxifloxacin against 20 FI+ and 20 FI- strains of Yersinia pestis was studied. It was shown that the strains were highly susceptible to the fluoroquinolones. In the experiments on mice subcutaneously infected with suspension of strains 231 FI+ and 231 FI- of Y. pestis in a dose of about 1000 LD50 (10(4) microbial cells) the ED50 of levofloxacin and moxifloxacin was 5.5-14.0 mg/kg independent of the infective culture phenotype and that of lomefloxacin was 18.5 mg/kg. Estimation of the impact of the pathogen infective dose value on the results of the experimental plague treatment with the therapeutic dose equivalent to the human one showed high efficacy of the fluoroquinolones (efficacy index of 10(4)). The treatment for 7 days provided 90-100-percent survival of the animals. The prophylactive use of lomefloxacin (in 5 hours - 5 days) was less efficient (70-80% of the survivals) in the animals infected with the antigen-changed (FI-) variant of the pathogen. Levofloxacin and moxifloxacin provided 90-100-percent survival of the animals treated for a course of 5 days independent of the pathogen phenotype. The study demonstrated that the use oflevofloxacin, lomefloxacin and moxifloxacin was prospective for the prophylaxis and therapy of experimental plague.

  9. Conjugal immunity of Streptomyces strains carrying the integrative element pSAM2 is due to the pif gene (pSAM2 immunity factor).

    PubMed

    Possoz, Christophe; Gagnat, Josette; Sezonov, Guennadi; Guérineau, Michel; Pernodet, Jean-Luc

    2003-03-01

    Mechanisms of conjugal immunity preventing redundant exchange between two cells harbouring the same conjugative element have been reported in diverse bacteria. Such a system does exist for pSAM2, a conjugative and integrative element of Streptomyces. The apparition of the conjugative free form of pSAM2 in the donor strain during mating can be considered as the initial step of transfer. We analysed the genes involved in transfer inhibition by mating donors harbouring pSAM2 with recipient strains containing different regions of pSAM2. The conjugal immunity was previously thought to be mediated by the transcriptional repressor KorSA. Although the transfer efficiency is reduced by its presence in the recipient, the initiation of the transfer process is not affected. In contrast, the presence in the recipient strain of a single pSAM2 gene, pif (pSAM2 immunity factor), was sufficient to abolish both transfer and initiation of transfer. Thus, the clustered genes korSA and pif act complementarily to maintain pSAM2 in a 'prophage' state under non-conjugal conditions. KorSA is involved in intracellular signalling, whereas Pif participates in intercellular signalling. The Pif nudix motif is essential for its activity. This is the first protein of the nudix family shown to be involved in bacterial conjugation.

  10. Ciprofloxacin treatment failure in a murine model of pyelonephritis due to an AAC(6')-Ib-cr-producing Escherichia coli strain susceptible to ciprofloxacin in vitro.

    PubMed

    Guillard, T; Cambau, E; Chau, F; Massias, L; de Champs, C; Fantin, B

    2013-12-01

    AAC(6')-Ib-cr is a plasmid-mediated quinolone resistance mechanism described worldwide for Escherichia coli. Since it confers in vitro only a low level of resistance to ciprofloxacin, we evaluated its impact on the in vivo activity of ciprofloxacin. Isogenic strains were obtained by transferring plasmid p449, harboring aac(6')-Ib-cr, into the quinolone-susceptible strain E. coli CFT073-RR and its D87G gyrA mutant. MICs were 0.015, 0.06, 0.25, and 0.5 μg/ml against E. coli strains CFT073-RR, CFT073-RR/p449, CFT073-RR GyrA(r), and CFT073-RR GyrA(r)/p449, respectively. Bactericidal activity was reduced at 1× the MIC for the three resistant derivatives, while at a fixed concentration of 0.5 μg/ml, 99.9% killing was observed for all strains except E. coli CFT073-RR GyrA(r)/p449. In the murine model of pyelonephritis, an optimal regimen of ciprofloxacin (10 mg/kg of body weight twice a day [b.i.d.]) significantly decreased the bacterial count in the kidneys of mice infected with E. coli CFT073 (1.6 versus 4.3 log10 CFU/g of kidney compared to untreated controls; P = 0.0001), while no significant decrease was observed for E. coli CFT073-RR/p449 (2.7 versus 3.1 log10 CFU/g; P = 0.84), E. coli CFT073-RR GyrA(r) (4.2 versus 4.1 log10 CFU/g; P = 0.35), or E. coli CFT073-RR GyrA(r)/p449 (2.9 versus 3.6 log10 CFU/g; P = 0.47). While pharmacokinetic and pharmacodynamic (PK/PD) parameters accounted for ciprofloxacin failure against gyrA-containing mutants, this was not the case for the aac(6')-Ib-cr-containing strains, suggesting an in situ hydrolysis of ciprofloxacin in the latter case.

  11. A family cluster of hepatitis A virus due to an uncommon IA strain circulating in Campania (southern Italy), not associated with raw shellfish or berries: a wake-up call to implement vaccination against hepatitis A?

    PubMed

    Tosone, Grazia; Mascolo, Silvia; Bruni, Roberto; Taffon, Stefania; Equestre, Michele; Tosti, Maria Elena; Ciccaglione, Anna Rita; Martucci, Fiorella; Liberti, Alfonso; Iannece, Maria Donata; Orlando, Raffaele

    2016-09-01

    Hepatitis A virus is a widely occurring disease, with different prevalence rates between countries in the North and West and those in the South and East. In Italy endemicity is low/medium, but not homogeneously distributed: in the northern/central regions a large hepatitis A outbreak due to genotype IA, related to the consumption of contaminated mixed frozen berries, occurred between 2013 and 2014, whereas in southern Italian regions recurrent outbreaks of hepatitis A, due to the IB genotype, still result from consumption of raw seafood. In 2014 an uncommon genotype IA strain was isolated from five patients (2 adults and 3 children) with hepatitis A, living in the surroundings of Naples (Campania) who did not have any of the most common risk factors for hepatitis A in Italy, such as consumption of raw shellfish or frozen berries, or travel to endemic countries. Moreover, based on the analysis of viral sequences obtained, this strain differed from several others in the national database, which had been recently isolated during Italian outbreaks. This case report reinforces the need to implement both information campaigns about the prevention of hepatitis A and vaccination programmes in childhood; in addition, it would be suitable to sequence strains routinely not only during large outbreaks of hepatitis A in order to obtain a more detailed national database of HAV strains circulating in Italy.

  12. Strain Localization in Thin Films of Bi(Fe,Mn)O3 Due to the Formation of Stepped Mn(4+)-Rich Antiphase Boundaries.

    PubMed

    MacLaren, I; Sala, B; Andersson, S M L; Pennycook, T J; Xiong, J; Jia, Q X; Choi, E-M; MacManus-Driscoll, J L

    2015-12-01

    The atomic structure and chemistry of thin films of Bi(Fe,Mn)O3 (BFMO) films with a target composition of Bi2FeMnO6 on SrTiO3 are studied using scanning transmission electron microscopy imaging and electron energy loss spectroscopy. It is shown that Mn(4+)-rich antiphase boundaries are locally nucleated right at the film substrate and then form stepped structures that are approximately pyramidal in three dimensions. These have the effect of confining the material below the pyramids in a highly strained state with an out-of-plane lattice parameter close to 4.1 Å. Outside the area enclosed by the antiphase boundaries, the out-of-plane lattice parameter is much closer to bulk values for BFMO. This suggests that to improve the crystallographic perfection of the films whilst retaining the strain state through as much of the film as possible, ways need to be found to prevent nucleation of the antiphase boundaries. Since the antiphase boundaries seem to form from the interaction of Mn with the Ti in the substrate, one route to perform this would be to grow a thin buffer layer of pure BiFeO3 on the SrTiO3 substrate to minimise any Mn-Ti interactions.

  13. Strain localization in thin films of Bi(Fe,Mn)O3 due to the formation of stepped Mn4+-rich antiphase boundaries

    DOE PAGES

    MacLaren, I.; Sala, B.; Andersson, S. M. L.; ...

    2015-10-17

    Here, the atomic structure and chemistry of thin films of Bi(Fe,Mn)O3 (BFMO) films with a target composition of Bi2FeMnO6 on SrTiO3 are studied using scanning transmission electron microscopy imaging and electron energy loss spectroscopy. It is shown that Mn4+-rich antiphase boundaries are locally nucleated right at the film substrate and then form stepped structures that are approximately pyramidal in three dimensions. These have the effect of confining the material below the pyramids in a highly strained state with an out-of-plane lattice parameter close to 4.1 Å. Outside the area enclosed by the antiphase boundaries, the out-of-plane lattice parameter is muchmore » closer to bulk values for BFMO. This suggests that to improve the crystallographic perfection of the films whilst retaining the strain state through as much of the film as possible, ways need to be found to prevent nucleation of the antiphase boundaries. Since the antiphase boundaries seem to form from the interaction of Mn with the Ti in the substrate, one route to perform this would be to grow a thin buffer layer of pure BiFeO3 on the SrTiO3 substrate to minimise any Mn-Ti interactions.« less

  14. Long Range Ferromagnetic Order in LaCoO3-δ epitaxial films due to the interplay of epitaxial strain and oxygen vacancy ordering

    DOE PAGES

    Mehta, Virat; Biskup, Nevenko; Arenholz, E; ...

    2015-04-23

    We demonstrate that a combination of electronic structure modification and oxygen vacancy ordering can stabilize a long-range ferromagnetic ground state in epitaxial LaCoO3 thin films. Highest saturation magnetization values are found in the thin films in tension on SrTiO3 and (La,Sr)(Al,Ta)O3 substrates and the lowest values are found in thin films in compression on LaAlO3. Electron microscopy reveals oxygen vacancy ordering to varying degrees in all samples, although samples with the highest magnetization are the most defective. Element-specific x-ray absorption techniques reveal the presence of high spin Co2+ and Co3+ as well as low spin Co3+ in different proportions dependingmore » on the strain state. The interactions among the high spin Co ions and the oxygen vacancy superstructure are correlated with the stabilization of the long-range ferromagnetic order.« less

  15. Long-range ferromagnetic order in LaCoO3 -δ epitaxial films due to the interplay of epitaxial strain and oxygen vacancy ordering

    NASA Astrophysics Data System (ADS)

    Mehta, V. V.; Biskup, N.; Jenkins, C.; Arenholz, E.; Varela, M.; Suzuki, Y.

    2015-04-01

    We demonstrate that a combination of electronic structure modification and oxygen vacancy ordering can stabilize a long-range ferromagnetic ground state in epitaxial LaCoO3 thin films. Highest saturation magnetization values are found in the thin films in tension on SrTiO3 and (La ,Sr )(Al ,Ta )O3 substrates and the lowest values are found in thin films in compression on LaAlO3. Electron microscopy reveals oxygen vacancy ordering to varying degrees in all samples, although samples with the highest magnetization are the most defective. Element-specific x-ray absorption techniques reveal the presence of high spin Co2 + and Co3 + as well as low spin Co3 + in different proportions depending on the strain state. The interactions among the high spin Co ions and the oxygen vacancy superstructure are correlated with the stabilization of the long-range ferromagnetic order.

  16. Decrease of U(VI) Immobilization Capability of the Facultative Anaerobic Strain Paenibacillus sp. JG-TB8 under Anoxic Conditions Due to Strongly Reduced Phosphatase Activity

    PubMed Central

    Reitz, Thomas; Rossberg, Andre; Barkleit, Astrid; Selenska-Pobell, Sonja; Merroun, Mohamed L.

    2014-01-01

    Interactions of a facultative anaerobic bacterial isolate named Paenibacillus sp. JG-TB8 with U(VI) were studied under oxic and anoxic conditions in order to assess the influence of the oxygen-dependent cell metabolism on microbial uranium mobilization and immobilization. We demonstrated that aerobically and anaerobically grown cells of Paenibacillus sp. JG-TB8 accumulate uranium from aqueous solutions under acidic conditions (pH 2 to 6), under oxic and anoxic conditions. A combination of spectroscopic and microscopic methods revealed that the speciation of U(VI) associated with the cells of the strain depend on the pH as well as on the aeration conditions. At pH 2 and pH 3, uranium was exclusively bound by organic phosphate groups provided by cellular components, independently on the aeration conditions. At higher pH values, a part (pH 4.5) or the total amount (pH 6) of the dissolved uranium was precipitated under oxic conditions in a meta-autunite-like uranyl phosphate mineral phase without supplying an additional organic phosphate substrate. In contrast to that, under anoxic conditions no mineral formation was observed at pH 4.5 and pH 6, which was clearly assigned to decreased orthophosphate release by the cells. This in turn was caused by a suppression of the indigenous phosphatase activity of the strain. The results demonstrate that changes in the metabolism of facultative anaerobic microorganisms caused by the presence or absence of oxygen can decisively influence U(VI) biomineralization. PMID:25157416

  17. GENERAL ENHANCEMENT OF MUTAGENIC POTENCY OF VARIOUS MUTAGENS DUE TO DELETED GENES IN THE ΔuvrB STRAINS TA 98 AND TA 100 OF SALMONELLA COMPARED WITH STRAINS CONTAINING ONLY A POINT MUTATION IN uvrB

    EPA Science Inventory

    The two most common strains used in Ames mutagenicity assays, TA98 and TA 100, contain a �uvrB mutation designed to enhance the mutagenicity of compounds, presumably due to the loss of the nucleotide excision repair system. We showed previously that the �uvrB mutations in these s...

  18. Catheter colonization and abscess formation due to Staphylococcus epidermidis with normal and small-colony-variant phenotype is mouse strain dependent.

    PubMed

    Sander, Gunnar; Börner, Tina; Kriegeskorte, André; von Eiff, Christof; Becker, Karsten; Mahabir, Esther

    2012-01-01

    Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 10(6) to 10(9) colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 10(7) or 10(8) CFUs of the normal phenotype, respectively. A minimum dose of 10(8) or 10(9) CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm(2) vs. 28 mm(2)). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice.

  19. Long Range Ferromagnetic Order in LaCoO3-δ epitaxial films due to the interplay of epitaxial strain and oxygen vacancy ordering

    SciTech Connect

    Mehta, Virat; Biskup, Nevenko; Arenholz, E; Varela del Arco, Maria; Suzuki, Yuri

    2015-04-23

    We demonstrate that a combination of electronic structure modification and oxygen vacancy ordering can stabilize a long-range ferromagnetic ground state in epitaxial LaCoO3 thin films. Highest saturation magnetization values are found in the thin films in tension on SrTiO3 and (La,Sr)(Al,Ta)O3 substrates and the lowest values are found in thin films in compression on LaAlO3. Electron microscopy reveals oxygen vacancy ordering to varying degrees in all samples, although samples with the highest magnetization are the most defective. Element-specific x-ray absorption techniques reveal the presence of high spin Co2+ and Co3+ as well as low spin Co3+ in different proportions depending on the strain state. The interactions among the high spin Co ions and the oxygen vacancy superstructure are correlated with the stabilization of the long-range ferromagnetic order.

  20. [Case report of the first world death due to a new strain of human influenza A H1N1 virus and behavior of human influenzae in pregnant women].

    PubMed

    Noguera Sánchez, Marcelo Fidias; Karchmer Krivitzky, Samuel; EsliRabadán, Martínez Cesar; Antonio Sánchez, Pedro

    2013-01-01

    Influenza A H1N1 is an acute respiratory illness caused by a new strain of H1N1. Human influenza is a subtype of influenza Avirus, from the family of Orthomyxoviridae. This strain is the cause of new influenza pandemic declared by the World Health Organization in June, 2009. This paper reports the first case occurred in Mexico: a 39-year-old woman with a history of diabetes mellitus type 2 and obesity grade II, which suffered atypical and aggressive pneumonia positive to coronavirus. Patient died 98 hours after her admission to the hospital unit. Due to the clinical presentation of the case, the doctors sent samples to the Instituto Nacional de Diagnóstico y Referencia Epidemiológica that sent an aliquot of the National Center for Immunization and Respiratory Diseases of theAgency of Public Health in Canada, that reported positivity to influenza virus, and catalogued it as a new global strain called influenza A virus H1N1. The notice of 229E/NL63 coronavirus and its relationship to the recent outbreaks of avian influenza in humans and the clinical presentation of the case were the epidemiological circumstances that prevented the nation epidemiology system to establish global containment strategies to prevent the spread of this emerging infection. The consequence was the declaration of WHO pandemic alert level 6. Its behavior in pregnancy, reported by Assistant General Direction of Epidemiology in Mexico, has placed this infection as a risk factor for women.

  1. Efficacies of Imipenem, Meropenem, Cefepime, and Ceftazidime in Rats with Experimental Pneumonia Due to a Carbapenem-Hydrolyzing β-Lactamase-Producing Strain of Enterobacter cloacae

    PubMed Central

    Mimoz, Olivier; Leotard, Sophie; Jacolot, Anne; Padoin, Christophe; Louchahi, Kamel; Petitjean, Olivier; Nordmann, Patrice

    2000-01-01

    The antibacterial activities of imipenem-cilastatin, meropenem-cilastatin, cefepime and ceftazidime against Enterobacter cloacae NOR-1, which produces the carbapenem-hydrolyzing β-lactamase NmcA and a cephalosporinase, and against one of its in vitro-obtained ceftazidime-resistant mutant were compared by using an experimental model of pneumonia with immunocompetent rats. The MICs of the β-lactams with an inoculum of 5 log10 CFU/ml were as follows for E. cloacae NOR-1 and its ceftazidime-resistant mutant, respectively: imipenem, 16 and 128 μg/ml, meropenem, 4 and 32 μg/ml, cefepime, <0.03 and 1 μg/ml, and ceftazidime, 1 and 512 μg/ml. The chromosomally located cephalosporinase and carbapenem-hydrolyzing β-lactamase NmcA were inducible by cefoxitin and meropenem in E. cloacae NOR-1, and both were stably overproduced in the ceftazidime-resistant mutant. Renal impairment was induced (uranyl nitrate, 1 mg/kg of body weight) in rats to simulate the human pharmacokinetic parameters for the β-lactams studied. Animals were intratracheally inoculated with 8.5 log10 CFU of E. cloacae, and therapy was initiated 3 h later. At that time, animal lungs showed bilateral pneumonia containing more than 6 log10 CFU of E. cloacae per g of tissue. Despite the relative low MIC of meropenem for E. cloacae NOR-1, the carbapenem-treated rats had no decrease in bacterial counts in their lungs 60 h after therapy onset compared to the counts for the controls, regardless of whether E. cloacae NOR-1 or its ceftazidime-resistant mutant was inoculated. A significant decrease in bacterial titers was observed for the ceftazidime-treated rats infected with E. cloacae NOR-1 only. Cefepime was the only β-lactam tested effective as treatment against infections due to E. cloacae NOR-1 or its ceftazidime-resistant mutant. PMID:10722486

  2. High temperature strain gage apparent strain compensation

    NASA Technical Reports Server (NTRS)

    Holmes, Harlan K.; Moore, T. C., Sr.

    1992-01-01

    Once an installed strain gage is connected to a strain indicating device and the instrument is balanced, a subsequent change in temperature of the gage installation will generally produce a resistance change in the gage. This purely temperature-induced resistance will be registered by the indicating device as a strain and is referred to as 'apparent strain' to distinguish it from strain due to applied stress. One desirable technique for apparent strain compensation is to employ two identical gages with identical mounting procedures which are connected with a 'half bridge' configuration where gages see the same thermal environment but only one experiences a mechanical strain input. Their connection in adjacent arms of the bridge will then balance the thermally induced apparent strains and, in principle, only the mechanical strain remains. Two approaches that implement this technique are discussed.

  3. Characterization of a Nosocomial Outbreak Caused by a Multiresistant Acinetobacter baumannii Strain with a Carbapenem-Hydrolyzing Enzyme: High-Level Carbapenem Resistance in A. baumannii Is Not Due Solely to the Presence of β-Lactamases

    PubMed Central

    Bou, Germán; Cerveró, Gonzalo; Domínguez, M. Angeles; Quereda, Carmen; Martínez-Beltrán, Jesús

    2000-01-01

    From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid, Spain, were determined to be either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs, 128 to 256 μg/ml). A wide antibiotic multiresistance profile was observed with IMRAB strains. For typing IMRAB isolates, pulsed-field gel electrophoresis was used. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during, and after the outbreak were included in this study. The molecular-typing results showed that the outbreak was caused by a single IMRAB strain (genotype A). By cloning experiments we identified a class D β-lactamase (OXA-24) encoded in the chromosomal DNA of this IMRAB strain which showed carbapenem hydrolysis. Moreover, the outer membrane profile of the IMRAB strain showed a reduction in the expression of two porins at 22 and 33 kDa when compared with genetically related IMSAB isolates. In addition no efflux mechanisms were identified in the IMRAB strains. In summary, we report here the molecular characterization of a nosocomial outbreak caused by one multiresistant A. baumannii epidemic strain that harbors a carbapenem-hydrolyzing enzyme. Although alterations in the penicillin-binding proteins cannot be ruled out, the reduction in the expression of two porins and the presence of this OXA-derived β-lactamase are involved in the carbapenem resistance of the epidemic nosocomial IMRAB strain. PMID:10970374

  4. Natural Strain

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1995-01-01

    The purpose of this paper is to present a consistent and thorough development of the strain and strain-rate measures affiliated with Hencky. Natural measures for strain and strain-rate, as I refer to them, are first expressed in terms of of the fundamental body-metric tensors of Lodge. These strain and strain-rate measures are mixed tensor fields. They are mapped from the body to space in both the Eulerian and Lagrangian configurations, and then transformed from general to Cartesian fields. There they are compared with the various strain and strain-rate measures found in the literature. A simple Cartesian description for Hencky strain-rate in the Lagrangian state is obtained.

  5. Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi2Sr2CaCu2Ox multifilament round wires

    NASA Astrophysics Data System (ADS)

    Ye, Liyang; Li, Pei; Jaroszynski, Jan; Schwartz, Justin; Shen, Tengming

    2017-02-01

    The critical current of many practical superconductors is sensitive to strain, and this sensitivity is exacerbated during a quench that induces a peak local strain which can be fatal to superconducting magnets. Here, a new method is introduced to quantify the influence of the conductor stress and strain state during normal operation on the margin to degradation during a quench, as measured by the maximum allowable hot spot temperature T allowable, for composite wires within superconducting magnets. The first conductor examined is Ag-sheathed Bi2Sr2CaCu2Ox round wire carrying high engineering critical current density, J E, of 550 A mm-2 at 4.2 K and 15 T. The critical axial tensile stress of this conductor is determined to be 150 MPa and, in the absence of Lorentz forces, T allowable is greater than 450 K. With increasing axial tensile stress, σ a, however, T allowable decreases nonlinearly, dropping to 280 K for σ a = 120 MPa and to 160 K for σ a = 145 MPa. T allowable(σ a) is shown to be nonlinear and independent of magnetic field from 15 to 30 T. T allowable(σ a) dictates the balance between magnetic field generation, which increases with the magnet operating current and stress, and the safety margin, which decreases with decreasing T allowable, and therefore has important engineering value. It is also shown that T allowable(σ a) can be predicted accurately by a general strain model, showing that strain control is the key to preventing degradation of superconductors during a quench.

  6. An Outbreak of Diarrhea in Mandera, Kenya, Due to Escherichia coli Serogroup O-Nontypable Strain That Had a Coding Gene for Enteroaggregative E. coli Heat-Stable Enterotoxin 1.

    PubMed

    Ochi, Sadayuki; Shah, Mohammad; Odoyo, Erick; Bundi, Martin; Miringu, Gabriel; Guyo, Sora; Wandera, Ernest; Kathiiko, Cyrus; Kariuki, Samuel; Karama, Mohamed; Tsuji, Takao; Ichinose, Yoshio

    2017-02-08

    In an outbreak of gastroenteritis in December 2009, in Mandera, Kenya, Escherichia coli O-nontypable (ONT) strain was isolated from stool specimens of patients (18/24, 75%). The E. coli ONT organisms could not be assigned to any of the recognized diarrheagenic groups of E. coli However, they possessed the enteroaggregative E. coli heat-stable enterotoxin-1 gene. The cell-free culture filtrates of the E. coli ONT strain isolated from the outbreak cases induced considerable amount of fluid accumulation in suckling mouse intestine, indicating production of an enterotoxic factor(s). These results identify E. coli that did not have any diarrheagenic characteristics except astA as the etiological agent of the diarrheal outbreak in Mandera. It is however considered necessary to characterize the fluid accumulation factor(s) to determine whether any novel toxins were responsible for the fluid accumulation. Moreover, it is important to study dissemination of strains producing the enterotoxic factor(s) to assess their public health significance distribution in the environment.

  7. Antipathogenic activity of probiotics against Salmonella Typhimurium and Clostridium difficile in anaerobic batch culture systems: is it due to synergies in probiotic mixtures or the specificity of single strains?

    PubMed

    Tejero-Sariñena, Sandra; Barlow, Janine; Costabile, Adele; Gibson, Glenn R; Rowland, Ian

    2013-12-01

    Probiotics are currently being investigated for prevention of infections caused by enteric pathogens. The aim of this in vitro study was to evaluate the influence of three single probiotics: Lactobacillus casei NCIMB 30185 (PXN 37), Lactobacillus acidophilus NCIMB 30184 (PXN 35), Bifidobacterium breve NCIMB 30180 (PXN 25) and a probiotic mixture containing the above strains plus twelve other strains belonging to the Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus and Bacillus genera on the survival of Salmonella Typhimurium and Clostridium difficile using pH-controlled anaerobic batch cultures containing mixed faecal bacteria. Changes in relevant bacterial groups and effects of probiotic addition on survival of the two pathogens were assessed over 24 h. Quantitative analysis of bacterial populations revealed that there was a significant increase in lactobacilli and/or bifidobacteria numbers, depending on probiotic addition, compared with the control (no added probiotic). There was also a significant reduction in S. Typhimurium and C. difficile numbers in the presence of certain probiotics compared with controls. Of the probiotic treatments, two single strains namely L. casei NCIMB 30185 (PXN 37), and B. breve NCIMB 30180 (PXN 25) were the most potent in reducing the numbers of S. Typhimurium and C. difficile. In addition, the supplementation with probiotics into the systems influenced some fermentations parameters. Acetate was found in the largest concentrations in all vessels and lactate and formate were generally detected in higher amounts in vessels with probiotic addition compared to controls.

  8. Strain localization in thin films of Bi(Fe,Mn)O3 due to the formation of stepped Mn4+-rich antiphase boundaries

    SciTech Connect

    MacLaren, I.; Sala, B.; Andersson, S. M. L.; Pennycook, T. J.; Xiong, Jia; Jia, Q. X.; Choi, E. -M.; MacManus-Driscoll, J. L.

    2015-10-17

    Here, the atomic structure and chemistry of thin films of Bi(Fe,Mn)O3 (BFMO) films with a target composition of Bi2FeMnO6 on SrTiO3 are studied using scanning transmission electron microscopy imaging and electron energy loss spectroscopy. It is shown that Mn4+-rich antiphase boundaries are locally nucleated right at the film substrate and then form stepped structures that are approximately pyramidal in three dimensions. These have the effect of confining the material below the pyramids in a highly strained state with an out-of-plane lattice parameter close to 4.1 Å. Outside the area enclosed by the antiphase boundaries, the out-of-plane lattice parameter is much closer to bulk values for BFMO. This suggests that to improve the crystallographic perfection of the films whilst retaining the strain state through as much of the film as possible, ways need to be found to prevent nucleation of the antiphase boundaries. Since the antiphase boundaries seem to form from the interaction of Mn with the Ti in the substrate, one route to perform this would be to grow a thin buffer layer of pure BiFeO3 on the SrTiO3 substrate to minimise any Mn-Ti interactions.

  9. Strain Gage

    NASA Technical Reports Server (NTRS)

    1995-01-01

    HITEC Corporation developed a strain gage application for DanteII, a mobile robot developed for NASA. The gage measured bending forces on the robot's legs and warned human controllers when acceptable forces were exceeded. HITEC further developed the technology for strain gage services in creating transducers out of "Indy" racing car suspension pushrods, NASCAR suspension components and components used in motion control.

  10. 38 CFR 4.58 - Arthritis due to strain.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... With service incurred lower extremity amputation or shortening, a disabling arthritis, developing in... associated with the leg amputation or shortening, will be considered as service incurred, provided, however... amputation will not be granted service connection. This will generally require separate evaluation of...

  11. 38 CFR 4.58 - Arthritis due to strain.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... With service incurred lower extremity amputation or shortening, a disabling arthritis, developing in... associated with the leg amputation or shortening, will be considered as service incurred, provided, however... amputation will not be granted service connection. This will generally require separate evaluation of...

  12. 38 CFR 4.58 - Arthritis due to strain.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... With service incurred lower extremity amputation or shortening, a disabling arthritis, developing in... associated with the leg amputation or shortening, will be considered as service incurred, provided, however... amputation will not be granted service connection. This will generally require separate evaluation of...

  13. 38 CFR 4.58 - Arthritis due to strain.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... With service incurred lower extremity amputation or shortening, a disabling arthritis, developing in... associated with the leg amputation or shortening, will be considered as service incurred, provided, however... amputation will not be granted service connection. This will generally require separate evaluation of...

  14. 38 CFR 4.58 - Arthritis due to strain.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... With service incurred lower extremity amputation or shortening, a disabling arthritis, developing in... associated with the leg amputation or shortening, will be considered as service incurred, provided, however... amputation will not be granted service connection. This will generally require separate evaluation of...

  15. Enhancement of two dimensional electron gas concentrations due to Si{sub 3}N{sub 4} passivation on Al{sub 0.3}Ga{sub 0.7}N/GaN heterostructure: strain and interface capacitance analysis

    SciTech Connect

    Dinara, Syed Mukulika Jana, Sanjay Kr.; Ghosh, Saptarsi; Mukhopadhyay, Partha; Kumar, Rahul; Chakraborty, Apurba; Biswas, Dhrubes; Bhattacharya, Sekhar

    2015-04-15

    Enhancement of two dimensional electron gas (2DEG) concentrations at Al{sub 0.3}Ga{sub 0.7}N/GaN hetero interface after a-Si{sub 3}N{sub 4} (SiN) passivation has been investigated from non-destructive High Resolution X-ray Diffraction (HRXRD) analysis, depletion depth and capacitance-voltage (C-V) profile measurement. The crystalline quality and strained in-plane lattice parameters of Al{sub 0.3}Ga{sub 0.7}N and GaN were evaluated from double axis (002) symmetric (ω-2θ) diffraction scan and double axis (105) asymmetric reciprocal space mapping (DA RSM) which revealed that the tensile strain of the Al{sub 0.3}Ga{sub 0.7}N layer increased by 15.6% after SiN passivation. In accordance with the predictions from theoretical solution of Schrödinger-Poisson’s equations, both electrochemical capacitance voltage (ECV) depletion depth profile and C-V characteristics analyses were performed which implied effective 9.5% increase in 2DEG carrier density after passivation. The enhancement of polarization charges results from increased tensile strain in the Al{sub 0.3}Ga{sub 0.7}N layer and also due to the decreased surface states at the interface of SiN/Al{sub 0.3}Ga{sub 0.7}N layer, effectively improving the carrier confinement at the interface.

  16. Simulation and Analysis of Strain Sensitivity of CNT-Based Strain Sensors

    NASA Astrophysics Data System (ADS)

    Sapra, Gaurav; Vig, Renu; Sharma, Manu

    2016-10-01

    Carbon nanotubes (CNT) is turning out to be a replacement to all the existing traditional sensors due to their high gauge factor, multidirectional sensing capability, high flexibility, low mass density, high dynamic range and high sensitivity to strains at nano and macro- scales. The strain sensitivity of CNT-based strain sensors depends on number of parameters; quality and quantity of CNT used, type of polymer used, deposition and dispersion technique adopted and also on environmental conditions. Due to all these parameters, the piezoresistive behavior of CNT is diversified and it needs to be explored. This paper theoretically analyses the strain sensitivity of CNT-based strain sensors. The strain sensitivity response of CNT strain sensor is a result of change in total resistance of CNT network with respect to applied strain. The total resistance of CNT network consists of intrinsic resistance and inter-tube resistance. It has been found that the change in intrinsic resistance under strain is due to the variation of bandgap of individual, which depends on the chirality of the tube and it varies exponentially with strain. The inter-tube resistance of CNT network changes nonlinearly due to change in distance between neighboring CNTs with respect to applied strain. As the distance d between CNTs increases due to applied strain, tunneling resistance Rtunnel increases nonlinearly in exponential manner. When the concentration of CNTs in composite is close to percolation threshold, then the change of inter-tube resistances is more dominant than intrinsic resistance. At percolation threshold, the total resistance of CNT networks changes nonlinearly and this effect of nonlinearity is due to tunneling effect. The strain sensitivity of CNT-based strain sensors also varies nonlinearly with the change in temperature. For the change of temperature from -20∘C to 50∘C, there is more than 100% change in strain sensitivity of CNT/polymer composite strain sensor. This change is

  17. Sadovskii vortex in strain

    NASA Astrophysics Data System (ADS)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2015-11-01

    Sadovskii vortices are patches of fluid with uniform vorticity surrounded by a vortex sheet. They were first constructed as models for wakes behind bluff objects. We investigate the Sadovskii vortex in a straining field and examine limiting cases to validate our computational method. One limit is the patch vortex in strain (Moore & Saffman, Aircraft wake turbulence and its detection 1971), where there is no vortex sheet. We solve this as a free-boundary problem, and show that a simple method using the Biot-Savart law quickly gives solutions for stable shapes. When used for the more elongated (stronger straining field) situations, the method also leads to new vortex shapes. In the hollow vortex case, where there is no vortex patch and the circulation is entirely due to the vortex sheet (Llewellyn Smith and Crowdy, J. Fluid Mech. 691 2012), we use the Birkhoff-Rott equation to calculate the velocity of the fluid on the vortex boundary. The combination of these two methods can then be used to calculate the shape and velocity field of the Sadovksii vortex in strain.

  18. Strain balanced quantum posts

    SciTech Connect

    Alonso-Alvarez, D.; Alen, B.; Ripalda, J. M.; Llorens, J. M.; Taboada, A. G.; Briones, F.; Roldan, M. A.; Hernandez-Saz, J.; Hernandez-Maldonado, D.; Herrera, M.; Molina, S. I.

    2011-04-25

    Quantum posts are assembled by epitaxial growth of closely spaced quantum dot layers, modulating the composition of a semiconductor alloy, typically InGaAs. In contrast with most self-assembled nanostructures, the height of quantum posts can be controlled with nanometer precision, up to a maximum value limited by the accumulated stress due to the lattice mismatch. Here, we present a strain compensation technique based on the controlled incorporation of phosphorous, which substantially increases the maximum attainable quantum post height. The luminescence from the resulting nanostructures presents giant linear polarization anisotropy.

  19. Geobacteraceae strains and methods

    DOEpatents

    Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

    2015-07-07

    Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

  20. Sadovskii vortex in strain

    NASA Astrophysics Data System (ADS)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2014-11-01

    A Sadovskii vortex is a patch of fluid with uniform vorticity surrounded by a vortex sheet. Using a boundary element type method, we investigate the steady states of this flow in an incompressible, inviscid straining flow. Outside the vortex, the fluid is irrotational. In the limiting case where the entire circulation is due to the vortex patch, this is a patch vortex (Moore & Saffman, Aircraft wake turbulence and its detection 1971). In the other limiting case, where all the circulation is due to the vortex sheet, this is a hollow vortex (Llewellyn Smith and Crowdy, J. Fluid Mech. 691, 2012). This flow has two governing nondimensional parameters, relating the strengths of the straining field, vortex sheet, and patch vorticity. We study the relationship between these two parameters, and examine the shape of the resulting vortices. We also work towards a bifurcation diagram of the steady states of the Sadovskii vortex in an attempt to understand the connection between vortex sheet and vortex patch desingularizations of the point vortex. Support from NSF-CMMI-0970113.

  1. Muscle strain treatment

    MedlinePlus

    Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...

  2. Muscle strain (image)

    MedlinePlus

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  3. Due process traditionalism.

    PubMed

    Sunstein, Cass R

    2008-06-01

    In important cases, the Supreme Court has limited the scope of "substantive due process" by reference to tradition, but it has yet to explain why it has done so. Due process traditionalism might be defended in several distinctive ways. The most ambitious defense draws on a set of ideas associated with Edmund Burke and Friedrich Hayek, who suggested that traditions have special credentials by virtue of their acceptance by many minds. But this defense runs into three problems. Those who have participated in a tradition may not have accepted any relevant proposition; they might suffer from a systematic bias; and they might have joined a cascade. An alternative defense sees due process traditionalism as a second-best substitute for two preferable alternatives: a purely procedural approach to the Due Process Clause, and an approach that gives legislatures the benefit of every reasonable doubt. But it is not clear that in these domains, the first-best approaches are especially attractive; and even if they are, the second-best may be an unacceptably crude substitute. The most plausible defense of due process traditionalism operates on rule-consequentialist grounds, with the suggestion that even if traditions are not great, they are often good, and judges do best if they defer to traditions rather than attempting to specify the content of "liberty" on their own. But the rule-consequentialist defense depends on controversial and probably false assumptions about the likely goodness of traditions and the institutional incapacities of judges.

  4. Novel pre-strain method for dielectric electroactive polymers

    NASA Astrophysics Data System (ADS)

    Newell, Brittany; Krutz, Gary; Stewart, Frank; Pascal, Kevin

    2016-04-01

    Dielectric electroactive polymers have demonstrated their significant potential in a variety of applications due to their material strength and elastomeric material properties. Mechanical pre-strain has been shown to enhance material actuation potential significantly. However, with this enhancement comes sacrifices. Mechanical pre-strain imposes a stiff mechanical boundary on the dielectric material in order to maintain the strain. In this research, investigations were made into the mechanisms of mechanical pre-strain and into alternate pre-strain methods. These studies discovered alternate methods capable of producing enhanced pre-strains and final actuation without the addition of the solid strain boundary.

  5. Strain amplification in the bone mechanosensory system.

    PubMed

    Cowin, S C; Weinbaum, S

    1998-09-01

    This article discusses the potential mechanisms by which the strain induced at the membrane of an osteocyte may be amplified from the strain experienced by the whole bone due to mechanical loading. These mechanisms address the question of how these mechanical load-induced small strains of (typically) about 0.1% (but up to 0.5%) applied to a whole bone are amplified to strains of 1% or larger at the membrane of the osteocyte buried in its lacuna in the bone matrix. The answer to this question is an important link in the mechanosensory system in bone and in relating in vitro cell studies to in vivo cellular response.

  6. Superlattice strain gage

    DOEpatents

    Noel, B.W.; Smith, D.L.; Sinha, D.N.

    1988-06-28

    A strain gage comprising a strained-layer superlattice crystal exhibiting piezoelectric properties is described. A substrate upon which such a strained-layer superlattice crystal has been deposited is attached to an element to be monitored for strain. A light source is focused on the superlattice crystal and the light reflected from, passed through, or emitted from the crystal is gathered and compared with previously obtained optical property data to determine the strain in the element. 8 figs.

  7. Superlattice strain gage

    DOEpatents

    Noel, Bruce W.; Smith, Darryl L.; Sinha, Dipen N.

    1990-01-01

    A strain gage comprising a strained-layer superlattice crystal exhibiting piezoelectric properties is described. A substrate upon which such a strained-layer superlattice crystal has been deposited is attached to an element to be monitored for strain. A light source is focused on the superlattice crystal and the light reflected from, passed through, or emitted from the crystal is gathered and compared with previously obtained optical property data to determine the strain in the element.

  8. Distributed strain monitoring for bridges: temperature effects

    NASA Astrophysics Data System (ADS)

    Regier, Ryan; Hoult, Neil A.

    2014-03-01

    To better manage infrastructure assets as they reach the end of their service lives, quantitative data is required to better assess structural behavior and allow for more informed decision making. Distributed fiber optic strain sensors are one sensing technology that could provide comprehensive data for use in structural assessments as these systems potentially allow for strain to be measured with the same accuracy and gage lengths as conventional strain sensors. However, as with many sensor technologies, temperature can play an important role in terms of both the structure's and sensor's performance. To investigate this issue a fiber optic distributed strain sensor system was installed on a section of a two span reinforced concrete bridge on the TransCanada Highway. Strain data was acquired several times a day as well as over the course of several months to explore the effects of changing temperature on the data. The results show that the strain measurements are affected by the bridge behavior as a whole. The strain measurements due to temperature are compared to strain measurements that were taken during a load test on the bridge. The results show that even a small change in temperature can produce crack width and strain changes similar to those due to a fully loaded transport truck. Future directions for research in this area are outlined.

  9. Mechanical strain effects on black phosphorus nanoresonators.

    PubMed

    Wang, Cui-Xia; Zhang, Chao; Jiang, Jin-Wu; Park, Harold S; Rabczuk, Timon

    2016-01-14

    We perform classical molecular dynamics simulations to investigate the effects of mechanical strain on single-layer black phosphorus nanoresonators at different temperatures. We find that the resonant frequency is highly anisotropic in black phosphorus due to its intrinsic puckered configuration, and that the quality factor in the armchair direction is higher than in the zigzag direction at room temperature. The quality factors are also found to be intrinsically larger than those in graphene and MoS2 nanoresonators. The quality factors can be increased by more than a factor of two by applying tensile strain, with uniaxial strain in the armchair direction being the most effective. However, there is an upper bound for the quality factor increase due to nonlinear effects at large strains, after which the quality factor decreases. The tension induced nonlinear effect is stronger along the zigzag direction, resulting in a smaller maximum strain for quality factor enhancement.

  10. Optical Strain Measurement System Development

    NASA Technical Reports Server (NTRS)

    Lant, C. T.

    1985-01-01

    Investigations of physical phenomena affecting the durability of SSME components require measurement systems operational in hostile environments. The need for such instrumentation caused the definition and operation of an optical strain measurement system. This optical strain measurement system based on the speckle shift method is being developed. This is a noncontact, automatic method of measuring surface strain in one dimension that corrects for error due to rigid body motion. It provides a gauge length of 1 to 2 mm and allows the region of interest on the test specimen to be mapped point by point. The output is a graphics map of the points inspected on the specimen; data points is stored in quasi-real time. This is the first phase of a multiphase effort in optical strain measurement. The speckle pattern created by the test specimen is interpreted as high order interference fringes resulting from a random diffraction grating, being the natural surface roughness of the specimen. Strain induced on the specimen causes a change in spacing of the surface roughness, which in turn shifts the position of the interference pattern (speckles).

  11. [Onychomycoses due to molds].

    PubMed

    Chabasse, D; Pihet, M

    2014-12-01

    Onychomycoses represent about 30% of superficial mycosis that are encountered in Dermatology consults. Fungi such as dermatophytes, which are mainly found on the feet nails, cause nearly 50% of these onychopathies. Yeasts are predominantly present on hands, whereas non-dermatophytic moulds are very seldom involved in both foot and hand nails infections. According to literature, these moulds are responsible for 2 to 17% of onychomycoses. Nevertheless, we have to differentiate between onychomycoses due to pseudodermatophytes such as Neoscytalidium (ex-Scytalidium) and Onychocola canadensis, which present a high affinity for keratin, and onychomycoses due to filamentous fungi such as Aspergillus, Fusarium, Scopulariopsis, Acremonium... These saprophytic moulds are indeed most of the time considered as colonizers rather than real pathogens agents. Mycology and histopathology laboratories play an important role. They allow to identify the species that is involved in nail infection, but also to confirm parasitism by the fungus in the infected nails. Indeed, before attributing any pathogenic role to non-dermatophytic moulds, it is essential to precisely evaluate their pathogenicity through samples and accurate mycological and/or histological analysis. The treatment of onychomycoses due to non-dermatophytic moulds is difficult, as there is today no consensus. The choice of an antifungal agent will first depend on the species that is involved in the infection, but also on the severity of nail lesions and on the patient himself. In most cases, the onychomycosis will be cured with chemical or mechanical removing of the infected tissues, followed by a local antifungal treatment. In some cases, a systemic therapy will be discussed.

  12. Credit where due.

    PubMed

    Friedman, Steven G

    2016-08-01

    The history of medicine is filled with stories of tireless researchers who failed to get credit for their hard work. Examples of this include Rosalind Franklin, who helped to elucidate the structure of DNA; Frederick Banting, who helped to discover insulin; and Jay McLean, who discovered heparin. The founding of the field of vascular surgery provides one of the most vivid examples of uncredited work. Even though Alexis Carrel was an unpaid, untitled assistant in Charles Guthrie's laboratory, it was Carrel alone who received a Nobel Prize for their work. In an attempt to give credit where due, the reasons for this injustice are described.

  13. Elevated temperature strain gages

    NASA Technical Reports Server (NTRS)

    Brittain, J. O.; Geslin, D.; Lei, J. F.

    1985-01-01

    Materials were evaluated that could be used in manufacturing electrical resistance strain gages for static strain measurements at temperatures at or above 1273 K. Strain gage materials must have a characteristic response to strain, temperature and time that is reproducible or that varies in a predictable manner within specified limits. Several metallic alloys were evaluated, as well as a series of transition metal carbides, nitrides and silicides.

  14. Sprains and Strains

    MedlinePlus

    ... happens. A strain is a stretched or torn muscle or tendon. Tendons are tissues that connect muscle to bone. Twisting or pulling these tissues can ... suddenly or develop over time. Back and hamstring muscle strains are common. Many people get strains playing ...

  15. Strain powered antennas

    NASA Astrophysics Data System (ADS)

    Domann, John P.; Carman, Greg P.

    2017-01-01

    This paper proposes the creation of strain powered antennas that radiate electromagnetic energy by mechanically vibrating a piezoelectric or piezomagnetic material. A closed form analytic model of electromagnetic radiation from a strain powered electrically small antenna is derived and analyzed. Fundamental scaling laws and the frequency dependence of strain powered antennas are discussed. The radiation efficiency of strain powered electrically small antennas is contrasted with a conventional electric dipole. Analytical results show that operating at the first mechanical resonance produces the most efficient strain powered radiation relative to electric dipole antennas. A resonant analysis is exploited to determine the material property space that produces efficient strain powered antennas. These results show how a properly designed strain powered antenna can radiate more efficiently than an equally sized electric dipole antenna.

  16. Extraordinary strain hardening by gradient structure.

    PubMed

    Wu, XiaoLei; Jiang, Ping; Chen, Liu; Yuan, Fuping; Zhu, Yuntian T

    2014-05-20

    Gradient structures have evolved over millions of years through natural selection and optimization in many biological systems such as bones and plant stems, where the structures change gradually from the surface to interior. The advantage of gradient structures is their maximization of physical and mechanical performance while minimizing material cost. Here we report that the gradient structure in engineering materials such as metals renders a unique extra strain hardening, which leads to high ductility. The grain-size gradient under uniaxial tension induces a macroscopic strain gradient and converts the applied uniaxial stress to multiaxial stresses due to the evolution of incompatible deformation along the gradient depth. Thereby the accumulation and interaction of dislocations are promoted, resulting in an extra strain hardening and an obvious strain hardening rate up-turn. Such extraordinary strain hardening, which is inherent to gradient structures and does not exist in homogeneous materials, provides a hitherto unknown strategy to develop strong and ductile materials by architecting heterogeneous nanostructures.

  17. Highly Invasive Listeria monocytogenes Strains Have Growth and Invasion Advantages in Strain Competition.

    PubMed

    Zilelidou, Evangelia A; Rychli, Kathrin; Manthou, Evanthia; Ciolacu, Luminita; Wagner, Martin; Skandamis, Panagiotis N

    2015-01-01

    Multiple Listeria monocytogenes strains can be present in the same food sample; moreover, infection with more than one L. monocytogenes strain can also occur. In this study we investigated the impact of strain competition on the growth and in vitro virulence potential of L. monocytogenes. We identified two strong competitor strains, whose growth was not (or only slightly) influenced by the presence of other strains and two weak competitor strains, which were outcompeted by other strains. Cell contact was essential for growth inhibition. In vitro virulence assays using human intestinal epithelial Caco2 cells showed a correlation between the invasion efficiency and growth inhibition: the strong growth competitor strains showed high invasiveness. Moreover, invasion efficiency of the highly invasive strain was further increased in certain combinations by the presence of a low invasive strain. In all tested combinations, the less invasive strain was outcompeted by the higher invasive strain. Studying the effect of cell contact on in vitro virulence competition revealed a complex pattern in which the observed effects depended only partially on cell-contact suggesting that competition occurs at two different levels: i) during co-cultivation prior to infection, which might influence the expression of virulence factors, and ii) during infection, when bacterial cells compete for the host cell. In conclusion, we show that growth of L. monocytogenes can be inhibited by strains of the same species leading potentially to biased recovery during enrichment procedures. Furthermore, the presence of more than one L. monocytogenes strain in food can lead to increased infection rates due to synergistic effects on the virulence potential.

  18. Highly Invasive Listeria monocytogenes Strains Have Growth and Invasion Advantages in Strain Competition

    PubMed Central

    Manthou, Evanthia; Ciolacu, Luminita; Wagner, Martin; Skandamis, Panagiotis N.

    2015-01-01

    Multiple Listeria monocytogenes strains can be present in the same food sample; moreover, infection with more than one L. monocytogenes strain can also occur. In this study we investigated the impact of strain competition on the growth and in vitro virulence potential of L. monocytogenes. We identified two strong competitor strains, whose growth was not (or only slightly) influenced by the presence of other strains and two weak competitor strains, which were outcompeted by other strains. Cell contact was essential for growth inhibition. In vitro virulence assays using human intestinal epithelial Caco2 cells showed a correlation between the invasion efficiency and growth inhibition: the strong growth competitor strains showed high invasiveness. Moreover, invasion efficiency of the highly invasive strain was further increased in certain combinations by the presence of a low invasive strain. In all tested combinations, the less invasive strain was outcompeted by the higher invasive strain. Studying the effect of cell contact on in vitro virulence competition revealed a complex pattern in which the observed effects depended only partially on cell-contact suggesting that competition occurs at two different levels: i) during co-cultivation prior to infection, which might influence the expression of virulence factors, and ii) during infection, when bacterial cells compete for the host cell. In conclusion, we show that growth of L. monocytogenes can be inhibited by strains of the same species leading potentially to biased recovery during enrichment procedures. Furthermore, the presence of more than one L. monocytogenes strain in food can lead to increased infection rates due to synergistic effects on the virulence potential. PMID:26529510

  19. Resolution of axial shear strain elastography

    NASA Astrophysics Data System (ADS)

    Thitaikumar, Arun; Righetti, Raffaella; Krouskop, Thomas A.; Ophir, Jonathan

    2006-10-01

    The technique of mapping the local axial component of the shear strain due to quasi-static axial compression is defined as axial shear strain elastography. In this paper, the spatial resolution of axial shear strain elastography is investigated through simulations, using an elastically stiff cylindrical lesion embedded in a homogeneously softer background. Resolution was defined as the smallest size of the inclusion for which the strain value at the inclusion/background interface was greater than the average of the axial shear strain values at the interface and inside the inclusion. The resolution was measured from the axial shear strain profile oriented at 45° to the axis of beam propagation, due to the absence of axial shear strain along the normal directions. The effects of the ultrasound system parameters such as bandwidth, beamwidth and transducer element pitch along with signal processing parameters such as correlation window length (W) and axial shift (ΔW) on the estimated resolution were investigated. The results show that the resolution (at 45° orientation) is determined by the bandwidth and the beamwidth. However, the upper bound on the resolution is limited by the larger of the beamwidth and the window length, which is scaled inversely to the bandwidth. The results also show that the resolution is proportional to the pitch and not significantly affected by the axial window shift.

  20. Strained graphene Hall bar

    NASA Astrophysics Data System (ADS)

    Milovanović, S. P.; Peeters, F. M.

    2017-02-01

    The effects of strain, induced by a Gaussian bump, on the magnetic field dependent transport properties of a graphene Hall bar are investigated. The numerical simulations are performed using both classical and quantum mechanical transport theory and we found that both approaches exhibit similar characteristic features. The effects of the Gaussian bump are manifested by a decrease of the bend resistance, R B, around zero-magnetic field and the occurrence of side-peaks in R B. These features are explained as a consequence of bump-assisted scattering of electrons towards different terminals of the Hall bar. Using these features we are able to give an estimate of the size of the bump. Additional oscillations in R B are found in the quantum description that are due to the population/depopulation of Landau levels. The bump has a minor influence on the Hall resistance even for very high values of the pseudo-magnetic field. When the bump is placed outside the center of the Hall bar valley polarized electrons can be collected in the leads.

  1. Three dimensional strained semiconductors

    DOEpatents

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  2. Strain sensor comprising a strain sensitive, two-mode optical

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

    1994-01-01

    A strain sensor uses an optical fiber including a strain sensitive portion and at least one strain insensitive portion. The strain sensitive portion is mounted on the surface of a structure at a location where a strain is desired to be measured. The strain insensitive portion(s) may be fused to the strain sensitive portion to transmit light therethrough, so that the resulting pattern may be detected to determine the amount of strain by comparison with a similar fiber not subjected to strain, or with the light pattern produced when the fiber is not under strain.

  3. Thin film strain transducer

    NASA Technical Reports Server (NTRS)

    Rand, J. L. (Inventor)

    1984-01-01

    A strain transducer system and process for making the same is disclosed. A beryllium copper ring having four strain gages is electrically connected in Wheatstone bridge fashion to the output instrumentation. Tabs are bonded to a balloon or like surface with strain on the surface causing bending of a ring which provides an electrical signal through the gages proportional to the surface strain. A photographic pattern of a one half ring segment as placed on a sheet of beryllium copper for chem-mill etch formation is illustrated.

  4. The Course of Due Process.

    ERIC Educational Resources Information Center

    Getty, Laura A.; Summy, Sarah E.

    2004-01-01

    Discussion of due process rights for children with disabilities considers common issues leading to due process requests, due process procedures, hearing officers, procedural violations, effects of due process meetings, and areas for improvement (i.e., accountability, paperwork). Tables list categories of procedural violations with examples and…

  5. Mechanical strain isolator mount

    NASA Technical Reports Server (NTRS)

    James, Gordon E. (Inventor)

    1991-01-01

    Certain devices such as optical instruments must preserve their alignmental integrity while being subjected to mechanical strain. A mechanical strain isolator mount is provided to preserve the alignmental integrity of an alignment sensitive instrument. An alignment sensitive instrument is mounted on a rectangular base. Flexural legs are connected at their proximal ends to the rectangular base. Flexural legs are also spaced parallel to the sides. Mounting pads are connected to the legs at the distal end and the mechanical strain isolator mount is attached to the substrate by means of threaded bolts. When a mounting pad and its respective leg is subjected to lateral strain in either the X or Y direction via the substrate, the respective leg relieves the strain by bending in the direction of the strain. An axial strain on a mounting pad in the Z direction is relieved by a rotational motion of the legs in the direction of the strain. When the substrate is stress free, the flexural legs return to their original condition and thus preserve the original alignment integrity of the alignment sensitive instrument.

  6. Light intensity strain analysis

    NASA Technical Reports Server (NTRS)

    Williams, J. G. (Inventor)

    1973-01-01

    A process is described for the analysis of the strain field of structures subjected to large deformations involving a low modulus substrate having a high modulus, relatively thin coating. The optical properties of transmittance and reflectance are measured for the coated substrate while stressed and unstressed to indicate the strain field for the coated substrate.

  7. Negative strain rate sensitivity in bulk metallic glass and its similarities with the dynamic strain aging effect during deformation

    SciTech Connect

    Dalla Torre, Florian H.; Dubach, Alban; Siegrist, Marco E.; Loeffler, Joerg F.

    2006-08-28

    Detailed investigations were carried out on the deformation behavior of Zr-based monolithic bulk metallic glass and bulk metallic glass matrix composites. The latter, due to splitting and multiplication of shear bands, exhibits larger compressive strains than the former, without significant loss of strength. Serrated flow in conjunction with a negative strain rate sensitivity was observed in both materials. This observation, together with an increase in stress drops with increasing strain and their decrease with increasing strain rate, indicates phenomenologically close similarities with the dynamic strain aging deformation mechanism known for crystalline solids. The micromechanical mechanism of a shear event is discussed in light of these results.

  8. The complex evolution of strain during nanoscale patterning of 60 nm thick strained silicon layer directly on insulator

    NASA Astrophysics Data System (ADS)

    Moutanabbir, O.; Reiche, M.; Erfurth, W.; Naumann, F.; Petzold, M.; Gösele, U.

    2009-06-01

    The strain behavior in nanoscale patterned biaxial tensile strained Si layer on insulator is investigated in 60-nm-thick nanostructures with dimensions in the 80-400 nm range. The in-plane strain is evaluated by using UV micro-Raman. We found that less than 30% of the biaxial strain is maintained in the 200×200 nm2 nanostructures. This relaxation, due to the formation of free surfaces, becomes more important in smaller nanostructures. The strain is completely relieved at 80 nm. This phenomenon is described based on detailed three-dimensional finite element simulations. The anisotropic relaxation in rectangular nanostructures is also discussed.

  9. Molecular typing of Brucella melitensis endemic strains and differentiation from the vaccine strain Rev-1.

    PubMed

    Noutsios, Georgios T; Papi, Rigini M; Ekateriniadou, Loukia V; Minas, Anastasios; Kyriakidis, Dimitrios A

    2012-03-01

    In the present study forty-four Greek endemic strains of Br. melitensis and three reference strains were genotyped by Multi locus Variable Number Tandem Repeat (ML-VNTR) analysis based on an eight-base pair tandem repeat sequence that was revealed in eight loci of Br. melitensis genome. The forty-four strains were discriminated from the vaccine strain Rev-1 by Restriction Fragment Length Polymorphism (RFLP) and Denaturant Gradient Gel Electrophoresis (DGGE). The ML-VNTR analysis revealed that endemic, reference and vaccine strains are genetically closely related, while most of the loci tested (1, 2, 4, 5 and 7) are highly polymorphic with Hunter-Gaston Genetic Diversity Index (HGDI) values in the range of 0.939 to 0.775. Analysis of ML-VNTRs loci stability through in vitro passages proved that loci 1 and 5 are non stable. Therefore, vaccine strain can be discriminated from endemic strains by allele's clusters of loci 2, 4, 6 and 7. RFLP and DGGE were also employed to analyse omp2 gene and reveled different patterns among Rev-1 and endemic strains. In RFLP, Rev-1 revealed three fragments (282, 238 and 44 bp), while endemic strains two fragments (238 and 44 bp). As for DGGE, the electrophoretic mobility of Rev-1 is different from the endemic strains due to heterologous binding of DNA chains of omp2a and omp2b gene. Overall, our data show clearly that it is feasible to genotype endemic strains of Br. melitensis and differentiate them from vaccine strain Rev-1 with ML-VNTR, RFLP and DGGE techniques. These tools can be used for conventional investigations in brucellosis outbreaks.

  10. Controlled-strain rate tests at very low strain rates of 2618 aluminum at 200 C

    NASA Technical Reports Server (NTRS)

    Ding, J. L.; Lee, S. R.

    1988-01-01

    Constant strain rate tests and constant load creep tests were performed on 2618 aluminum at 200 C. The strain rates used in the constant strain rate tests were 10 to the minus 6, 10 to the minus 7, 10 to the minum 8, and 10 to the minus 9/sec. Due to the fact that the strain rates in both tests were comparable to each other, the similarities between them can therefore be studied. It was concluded that metals are essentially rate sensitive at elevated temperatures. The traditional definition of creep and plasticity used in the classical creep analysis is actually a reflection of the material behavior under different loading conditions. A constitutive equation based on the test data under one loading condition should work well for other loading conditions as long as the strain rates are in the same range as those under which the material constants are determined.

  11. Thin film strain transducer

    NASA Astrophysics Data System (ADS)

    Rand, J. L.

    1981-01-01

    Previous attempts to develop an appropriate sensor for measuring the stress or strain of high altitude balloons during flight are reviewed as well as the various conditions that must be met by such a device. The design, development and calibration of a transducer which promises to satisfy the necessary design constraints are described. The thin film strain transducer has a low effective modulus so as not to interfere with the strain that would naturally occur in the balloon. In addition, the transducer has a high sensitivity to longitudinal strain (7.216 mV/V/unit strain) which is constant for all temperature from room temperature to -80 C and all strains from 5 percent compression to 10 percent tensile strain. At the same time, the sensor is relatively insensitive (0.27 percent) to transverse forces. The device has a standard 350 ohm impedance which is compatible with available bridge balance, amplification and telemetry instrumentation now available for balloon flight. Recommendations are included for improved coatings to provide passive thermal control as well as model, tethered and full scale flight testing.

  12. Anemia Due to Excessive Bleeding

    MedlinePlus

    ... Anemia Due to Excessive Bleeding Iron Deficiency Anemia Vitamin Deficiency Anemia Anemia of Chronic Disease Aplastic Anemia Autoimmune ... Anemia Due to Excessive Bleeding Iron Deficiency Anemia Vitamin Deficiency Anemia Anemia of Chronic Disease Aplastic Anemia Autoimmune ...

  13. Strain gauge installation tool

    DOEpatents

    Conard, Lisa Marie

    1998-01-01

    A tool and a method for attaching a strain gauge to a test specimen by maaining alignment of, and applying pressure to, the strain gauge during the bonding of the gauge to the specimen. The tool comprises rigid and compliant pads attached to a spring-loaded clamp. The pads are shaped to conform to the specimen surface to which the gauge is to be bonded. The shape of the pads permits the tool to align itself to the specimen and to maintain alignment of the gauge to the specimen during the bond curing process. A simplified method of attaching a strain gauge is provided by use of the tool.

  14. Sprains and Strains

    MedlinePlus

    ... Typically, people with a strain experience pain, limited motion, muscle spasms, and possibly muscle weakness. They also ... program designed to prevent stiffness, improve range of motion, and restore the joint's normal flexibility and strength. ...

  15. Strains and Sprains

    MedlinePlus

    ... in the joint or muscle swelling and bruising warmth and redness of the injured area difficulty moving ... looks "bent" or misshapen signs of infection (increased warmth, redness, streaks, swelling, and pain) a strain or ...

  16. Strain and magnetic remanence

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham John

    1993-05-01

    Experimental data may be compatible with the hypothesis that a single direction of magnetic remanence rotates as a rigid marker with strains up to 40% shortening in coaxial, perfect flattening ( X = Y > Z). Detailed agreement with the passive line model is relatively poor for the specimens in which remanance is carried by magnetite. However, for this range of strains the differences with the passive line model (Wettstein's equation) are so slight that the latter model may be more easily employed to de-strain or restore deformed remanance to its original attitude. In the case of hematite-bearing remanences, the differences between the passive line and rigid marker model are even smaller because of the higher aspect ratios of grains of hematite. Therefore it is suggested that Wettstein's equation may be safely used to restore remanence after even higher strains, where the remanence is carried by hematite.

  17. Resistance fail strain gage technology as applied to composite materials

    NASA Technical Reports Server (NTRS)

    Tuttle, M. E.; Brinson, H. F.

    1985-01-01

    Existing strain gage technologies as applied to orthotropic composite materials are reviewed. The bonding procedures, transverse sensitivity effects, errors due to gage misalignment, and temperature compensation methods are addressed. Numerical examples are included where appropriate. It is shown that the orthotropic behavior of composites can result in experimental error which would not be expected based on practical experience with isotropic materials. In certain cases, the transverse sensitivity of strain gages and/or slight gage misalignment can result in strain measurement errors.

  18. Theory of strain in single-layer transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Rostami, Habib; Roldán, Rafael; Cappelluti, Emmanuele; Asgari, Reza; Guinea, Francisco

    2015-11-01

    Strain engineering has emerged as a powerful tool to modify the optical and electronic properties of two-dimensional crystals. Here we perform a systematic study of strained semiconducting transition metal dichalcogenides. The effect of strain is considered within a full Slater-Koster tight-binding model, which provides us with the band structure in the whole Brillouin zone (BZ). From this, we derive an effective low-energy model valid around the K point of the BZ, which includes terms up to second order in momentum and strain. For a generic profile of strain, we show that the solutions for this model can be expressed in terms of the harmonic oscillator and double quantum well models, for the valence and conduction bands respectively. We further study the shift of the position of the electron and hole band edges due to uniform strain. Finally, we discuss the importance of spin-strain coupling in these 2D semiconducting materials.

  19. Computer modelling of bone's adaptation: the role of normal strain, shear strain and fluid flow.

    PubMed

    Tiwari, Abhishek Kumar; Prasad, Jitendra

    2017-04-01

    Bone loss is a serious health problem. In vivo studies have found that mechanical stimulation may inhibit bone loss as elevated strain in bone induces osteogenesis, i.e. new bone formation. However, the exact relationship between mechanical environment and osteogenesis is less clear. Normal strain is considered as a prime stimulus of osteogenic activity; however, there are some instances in the literature where osteogenesis is observed in the vicinity of minimal normal strain, specifically near the neutral axis of bending in long bones. It suggests that osteogenesis may also be induced by other or secondary components of mechanical environment such as shear strain or canalicular fluid flow. As it is evident from the literature, shear strain and fluid flow can be potent stimuli of osteogenesis. This study presents a computational model to investigate the roles of these stimuli in bone adaptation. The model assumes that bone formation rate is roughly proportional to the normal, shear and fluid shear strain energy density above their osteogenic thresholds. In vivo osteogenesis due to cyclic cantilever bending of a murine tibia has been simulated. The model predicts results close to experimental findings when normal strain, and shear strain or fluid shear were combined. This study also gives a new perspective on the relation between osteogenic potential of micro-level fluid shear and that of macro-level bending shear. Attempts to establish such relations among the components of mechanical environment and corresponding osteogenesis may ultimately aid in the development of effective approaches to mitigating bone loss.

  20. Shock due to urosepsis: A multicentre study

    PubMed Central

    Yamamichi, Fukashi; Shigemura, Katsumi; Kitagawa, Koichi; Takaba, Kei; Tokimatsu, Issei; Arakawa, Soichi; Fujisawa, Masato

    2017-01-01

    Introduction Urosepsis is a severe infection that can cause shock afterwards. The purpose of this study is to investigate the clinical and bacterial risk factors for shock in those cases with urosepsis caused by urinary tract infection in a multicentre study. Methods Our study included 77 consecutive urosepsis cases from four hospitals. We examined factors such as patient characteristics, underlying disease, serum white blood cell (WBC) count, platelet count, C-reactive protein (CRP) level at the time of diagnosis of urosepsis, urinary tract occlusion, causative bacteria, and bacterial antibiotic susceptibilities. Statistical analyses were performed to assess the potential risk factors for shock during the clinical course of urosepsis by a multivariate analysis. Results We had 38 male and 39 female patients aged 25–104 (median 73). Underlying diseases included cancers (n=22, 28.6 %) and diabetes mellitus (n=17, 22.1 %). Positive blood culture was seen in 74 cases; these involved 88 bacterial strains, of which Escherichia coli was the most common (34 strains, 38.6 %). There were 31 cases with shock (40.3 %) and multivariate analyses demonstrated that serum CRP was the only clinical risk factor for shock due to urosepsis. Conclusions Our study demonstrated that serum CRP was a risk factor for shock during urosepsis in a multicentre analysis. Further prospective studies with a greater number of patients are needed to draw more definitive conclusions. PMID:28360956

  1. Flexible photonic crystals for strain sensing

    NASA Astrophysics Data System (ADS)

    Fortes, Luís M.; Gonçalves, M. Clara; Almeida, Rui M.

    2011-01-01

    Three-dimensional (3-D) photonic crystals (PCs) have been studied as possible strain sensing materials, based on strain-induced stop band frequency shifting. Self-assembly of polystyrene microspheres, achieved by sedimentation over a flexible polyimide tape substrate whose surface hydrophilicity was optimized in order to achieve maximum wettability, led to an organized 3-D direct opal template. This was infiltrated with a silica sol-gel solution by dip-coating or by chemical vapour deposition and an inverse opal structure was ultimately obtained by chemical dissolution of the polymer template. The structural and optical properties of these PCs have been studied by scanning electron microscopy (FE-SEM) and UV/visible spectroscopy under variable degrees of strain. FE-SEM showed the presence of ordered domains up to ∼30 μm2. A mechano-optical effect was evidenced by strain-induced shifting of the photonic stop band peak wavelength of the direct, infiltrated and inverse opals up to 50 nm in transmission mode, due to changes in interplanar spacing upon bending the flexible PCs. Optical response strain cycles were studied, suggesting the possible use of these structures in reversible photonic strain sensors integrated in sensor/actuator devices.

  2. Strain responsive concave and convex microlens arrays

    NASA Astrophysics Data System (ADS)

    Chandra, Dinesh; Yang, Shu; Lin, Pei-Chun

    2007-12-01

    We report the fabrication of single-component, strain responsive microlens arrays with real-time tunability. The concave lens array is fabricated by patterning hard oxide layer on a bidirectionally prestretched soft elastomer, poly(dimethylsiloxane) (PDMS) followed by confined buckling upon release of the prestrain. The convex microlens array is replica molded from the concave lenses in PDMS. Due to difference in lens formation mechanisms, the two types of lenses show different tunable range of focal length in response to the applied strain: large focal length change is observed from the concave microlens array, whereas that from the convex microlens array is much smaller.

  3. Ecoepidemics with Two Strains: Diseased Prey.

    NASA Astrophysics Data System (ADS)

    Elena, Elisa; Grammauro, Maria; Venturino, Ezio

    2011-09-01

    In this work we present a minimal model for an ecoepidemic situation with two diseases affecting the prey population. The main assumptions are the following ones. The predators recognize and hunt only the healthy prey. An infected prey of one strain becomes immune to the other one. The major finding shows that the two strains cannot simultaneously thrive in the system, contrary to the standard assumptions in epidemiology. But this rather unexpected and remarkable result, paralleling another one when the epidemics affects the predators, is most likely due to the assumptions made.

  4. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  5. Strain avalanches in plasticity

    NASA Astrophysics Data System (ADS)

    Argon, A. S.

    2013-09-01

    Plastic deformation at the mechanism level in all solids occurs in the form of discrete thermally activated individual stress relaxation events. While there are clear differences in mechanisms between dislocation mediated events in crystalline solids and by individual shear transformations in amorphous metals and semiconductors, such relaxation events interact strongly to form avalanches of strain bursts. In all cases the attendant distributions of released energy as amplitudes of acoustic emissions, or in serration amplitudes in flow stress, the levels of strain bursts are of fractal character with fractal exponents in the range from -1.5 to -2.0, having the character of phenomena of self-organized criticality, SOC. Here we examine strain avalanches in single crystals of ice, hcp metals, the jerky plastic deformations of nano-pillars of fcc and bcc metals deforming in compression, those in the plastic flow of bulk metallic glasses, all demonstrating the remarkable universality of character of plastic relaxation events.

  6. Strain gauge installation tool

    DOEpatents

    Conard, L.M.

    1998-06-16

    A tool and a method are disclosed for attaching a strain gauge to a test specimen by maintaining alignment of, and applying pressure to, the strain gauge during the bonding of the gauge to the specimen. The tool comprises rigid and compliant pads attached to a spring-loaded clamp. The pads are shaped to conform to the specimen surface to which the gauge is to be bonded. The shape of the pads permits the tool to align itself to the specimen and to maintain alignment of the gauge to the specimen during the bond curing process. A simplified method of attaching a strain gauge is provided by use of the tool. 6 figs.

  7. Radio frequency strain monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor); Rogowski, Robert S. (Inventor); Holben, Jr., Milford S. (Inventor)

    1989-01-01

    A radio frequency strain monitor includes a voltage controlled oscillator for generating an oscillating signal that is input into a propagation path. The propagation path is preferably bonded to the surface of a structure to be monitored and produces a propagated signal. A phase difference between the oscillating and propagated signals is detected and maintained at a substantially constant value which is preferably a multiple of 90.degree. by changing the frequency of the oscillating signal. Any change in frequency of the oscillating signal provides an indication of strain in the structure to which the propagation path is bonded.

  8. Muscle strain injuries.

    PubMed

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  9. The apparent strain stability and repeatability of a BCL3 resistance strain gage

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen

    1991-01-01

    Experiments were conducted at NASA-Lewis to study the effect of microstructural instability on the apparent strain stability and reproducibility of a BCL3 resistance strain gage. The resistance drift of the gage at various temperatures in the phase transition temperature range (PTTR) was measured. The effects of the heating and cooling rates with which the gage passed through the PTTR on the apparent strain characteristics of the gage were also studied. BCL3 gage, like other Fe-Cr-Al based gages, exhibited apparent strain instability in the temperature range of 700 to 1100 F due to the reversible microstructural transition the gage materials experienced in this temperature range. The BCL3 gage had a maximum apparent strain drift in the neighborhood of 770 F with an average drift rate of approx. -440 microstrain/hr in 2 hrs. The use of the BCL3 gage as well as other Fe-Cl-Al based gages for static strain measurements within the PTTR should be avoided unless the time durations in the PTTR are small enough to introduce a neglible drift. The microstructure transition that the BCL3 gage underwent occurred in the temperature range of 750 to 1050 F during heating and around 1000 to 800 F during cooling. The heating rate, and, in particular, the cooling rate with which the gage passed through the PTTR affected the shape and the repeatability of the apparent strain curve of the gage.

  10. Identification of diarrheagenic Escherichia coli strains from avian organic fertilizers.

    PubMed

    Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

    2014-08-28

    The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  11. The breaking strain of neutron star crust

    SciTech Connect

    Kadau, Kai; Horowitz, C J

    2009-01-01

    Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking strain of neutron star crust. With multimillion ion molecular dynamics simulations of Coulomb solids representing the crust, we show that the breaking strain of pure single crystals is very large and that impurities, defects, and grain boundaries only modestly reduce the breaking strain to around 0.1. Due to the collective behavior of the ions during failure found in our simulations, the neutron star crust is likely very strong and can support mountains large enough so that their gTavitational wave radiation could limit the spin periods of some stars and might be detectable in large scale interferometers. Furthermore, our microscopic modeling of neutron star crust material can help analyze mechanisms relevant in Magnetar Giant and Micro Flares.

  12. Onychomycosis Due to Nondermatophytic Molds

    PubMed Central

    Hwang, Sung Min; Ha, Gyoung Yim

    2012-01-01

    Background Although there have been many studies about onychomycosis due to nondermatophytic molds (NDM), few studies about etiologic agents including NDM in onychomycosis have been reported in Korea. Objective: This study investigated onychomycosis due to NDM in the Gyeongju area of Korea. Objective This study investigated onychomycosis due to NDM in the Gyeongju area of Korea. Methods In the 10-year period from 1999~2009, we reviewed 59 patients with onychomycosis due to NDM. The etiologic agents were identified by cultures on Sabouraud's Dextrose agar with and without cycloheximide. In some cases, internal transcribed spacer sequence analysis was done. NDM isolated considered pathogens when the presence of fungal elements was identified by direct microscopy observation and in follow-up cultures yielding the same fungi. Results Onychomycosis due to NDM comprised 2.3% of all onychomycosis. Of the 59 patients with onychomycosis due to NDM, 84.7% were toenail onychomycosis and 15.3% were fingernail onychomycosis. The incidence rate was highest in the fifth decade (27.1%). The ratio of male to female patients was 1:1.6. The frequency of associated diseases, in descending order, was hypertension, diabetes mellitus, and cerebral hematoma. Distal and lateral subungual onychomycosis (86.4%) was the most common clinical type of onychomycosis. Aspergillus spp. was the most frequently isolated etiologic agent of onychomycosis due to NDM (83.0%). Other causative agents were Scopulariopsis brevicaulis (10.2%), Acremonium spp. (3.4%), Fusarium solani (1.7%), and Chaetomium globosum (1.7%). Conclusion Because of the increase in onychomycosis due to NDM, we suggest the need of a careful mycological examination in patients with onychomycosis. PMID:22577268

  13. Occupational asthma due to azodicarbonamide.

    PubMed

    Kim, Cheol-Woo; Cho, Jae-Hwa; Leem, Jong-Han; Ryu, Jeong-Seon; Lee, Hong-Lyeol; Hong, Yun-Chul

    2004-04-30

    Azodicarbonamide is a low molecular weight foaming agent for plastics and rubbers. Azodicarbonamide can elicit acute and chronic health related problems due to its potential for pulmonary and cutaneous sensitization. Some cases of occupational asthma associated with exposure to azodicarbonamide have been reported, of which only a few cases were confirmed by specific inhalation challenges. Here, the first case of occupational asthma due to azodicarbonamide in Korea, in which the diagnosis was confirmed by specific inhalation challenge, is reported.

  14. [Otomycosis due to Scopulariopsis brevicaulis].

    PubMed

    Besbes, M; Makni, F; Cheikh-Rouhou, F; Sellami, H; Kharrat, K; Ayadi, A

    2002-01-01

    We report a case of otomycosis due to Scopulariopsis brevicaulis in a patient with left cholesteatomatous chronic otitis media who presented with otorrhea associated with left otalgia. Scopulariopsis brevicaulis is a fungus which is rarely described as causing otomycosis although it is a saprophyte and widespread in the environment. In this case the contamination could be due to intensive gardening with poor hygiene. Its mycologic diagnosis is relatively easy and nystatin remains the most effective treatment in this region.

  15. Strain gage barometric transmitter

    NASA Technical Reports Server (NTRS)

    Viton, P.

    1977-01-01

    A strain gage barometric transmitter for measuring the atmospheric pressure in severe environmental conditions is described. This equipment specifications are presented and its performance assessed. It is shown that this barometric sensor can measure the atmospheric pressure with a precision of 0.5 mb during a 6 month period.

  16. Hamstring strain - aftercare

    MedlinePlus

    ... not to push yourself too hard or too fast. A hamstring strain can recur, or your hamstring may tear. Talk to your provider before returning to work or any physical activity. Returning to normal activity too early can cause re-injury.

  17. Repetitive strain injury.

    PubMed

    Al-Otaibi, S T

    2001-05-01

    Repetitive strain injury is a group of musculoskeletal disorders affecting muscles, tendons, nerves and blood vessels. These disorders could be attributed to occupational causes; however non-occupational causes should be excluded. The management of these cases required a multidisciplinary team approach.

  18. Balloon film strain measurement

    NASA Astrophysics Data System (ADS)

    Rand, James L.

    In order to understand the state of stress in scientific balloons, a need exists for the measurement of film deformation in flight. The results of a flight test program are reported where material strain was measured for the first time during the inflation, launch, ascent and float of a typical natural shape, zero pressure scientific balloon.

  19. Apparent-Strain Correction for Combined Thermal and Mechanical Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; O'Neil, Teresa L.

    2007-01-01

    Combined thermal and mechanical testing requires that the total strain be corrected for the coefficient of thermal expansion mismatch between the strain gage and the specimen or apparent strain when the temperature varies while a mechanical load is being applied. Collecting data for an apparent strain test becomes problematic as the specimen size increases. If the test specimen cannot be placed in a variable temperature test chamber to generate apparent strain data with no mechanical loads, coupons can be used to generate the required data. The coupons, however, must have the same strain gage type, coefficient of thermal expansion, and constraints as the specimen to be useful. Obtaining apparent-strain data at temperatures lower than -320 F is challenging due to the difficulty to maintain steady-state and uniform temperatures on a given specimen. Equations to correct for apparent strain in a real-time fashion and data from apparent-strain tests for composite and metallic specimens over a temperature range from -450 F to +250 F are presented in this paper. Three approaches to extrapolate apparent-strain data from -320 F to -430 F are presented and compared to the measured apparent-strain data. The first two approaches use a subset of the apparent-strain curves between -320 F and 100 F to extrapolate to -430 F, while the third approach extrapolates the apparent-strain curve over the temperature range of -320 F to +250 F to -430 F. The first two approaches are superior to the third approach but the use of either of the first two approaches is contingent upon the degree of non-linearity of the apparent-strain curve.

  20. Torsion Strain Effects on Critical Currents of Hts Superconducting Tapes

    NASA Astrophysics Data System (ADS)

    Takayasu, Makoto; Minervini, Joseph V.; Bromberg, Leslie

    2010-04-01

    A torsional twist strain effect on the critical current of a thin HTS tape has been found to be well described by a longitudinal strain model taking into account the internal shortening compressive strains accompanied with the tensile longitudinal strains due to a torsional twist. The critical current of a twisted tape is given by the integration of the critical current densities corresponding to the strain distribution over the tape cross-section using axial strain data of the tape. The model is supported with experimental results of YBCO and BSCCO-2223 tapes. It has been also found that torsional twisting effects on the critical currents of a tape composing of the conventional lapped-tape cable and the twisted stacked-tape cable are described by the same equation as that of a twisted single tape.

  1. Biaxial compressive strain engineering in graphene/boron nitride heterostructures.

    PubMed

    Pan, Wei; Xiao, Jianliang; Zhu, Junwei; Yu, Chenxi; Zhang, Gang; Ni, Zhenhua; Watanabe, K; Taniguchi, T; Shi, Yi; Wang, Xinran

    2012-01-01

    Strain engineered graphene has been predicted to show many interesting physics and device applications. Here we study biaxial compressive strain in graphene/hexagonal boron nitride heterostructures after thermal cycling to high temperatures likely due to their thermal expansion coefficient mismatch. The appearance of sub-micron self-supporting bubbles indicates that the strain is spatially inhomogeneous. Finite element modeling suggests that the strain is concentrated on the edges with regular nano-scale wrinkles, which could be a playground for strain engineering in graphene. Raman spectroscopy and mapping is employed to quantitatively probe the magnitude and distribution of strain. From the temperature-dependent shifts of Raman G and 2D peaks, we estimate the TEC of graphene from room temperature to above 1000K for the first time.

  2. Strain engineering of diamond silicon vacancy centers in MEMS cantilevers

    NASA Astrophysics Data System (ADS)

    Meesala, Srujan; Sohn, Young-Ik; Atikian, Haig; Holzgrafe, Jeffrey; Zhang, Mian; Burek, Michael; Loncar, Marko

    2016-05-01

    The silicon vacancy (SiV) center in diamond has recently attracted attention as a solid state quantum emitter due to its attractive optical properties. We fabricate diamond MEMS cantilevers, and use electrostatic actuation to apply controlled strain fields to single SiV centers implanted in these devices. The strain response of the four electronic transitions of the SiV at 737 nm is measured via cryogenic (4 K) photoluminescence excitation. We demonstrate over 300 GHz of tuning for the mean transition frequency between the ground and excited states, and over 100 GHz of tuning for the orbital splittings within the ground and excited states. The interaction Hamiltonian for strain fields is inferred, and large strain susceptibilities of the order 1 PHz/strain are measured. We discuss prospects to utilize our device to reduce phonon-induced decoherence in SiV spin qubits, and to exploit the large strain susceptibilities for hybrid quantum systems based on nanomechanical resonators.

  3. Stochastic disease extinction in multistrain diseases with interacting strains

    NASA Astrophysics Data System (ADS)

    Bianco, Simone; Shaw, Leah; Schwartz, Ira

    2009-03-01

    The study of multistrain diseases, diseases with several coexisting strains, is a major challenge for mathematical biology. Examples of such diseases are influenza, HIV, dengue and ebola. In this work we present an agent-based model for multistrain diseases with strain interactions mediated by antibody-dependent enhancement. An individual infected with a strain develops antibodies which will protect him/her against all the strains. When the level of protection wanes, the presence of antibodies will enhance the infectiousness of the individual when an infection with a different strain occurs. This mechanism is called antibody-dependent enhancement (ADE). We use this model to investigate the role that fluctuations due to system size have on disease extinction paths and discuss how interactions mediated by ADE affect rates of disease fade-out. Finally, we discuss the effect that varying the number of strains has on disease extinction.

  4. Biaxial Compressive Strain Engineering in Graphene/Boron Nitride Heterostructures

    PubMed Central

    Pan, Wei; Xiao, Jianliang; Zhu, Junwei; Yu, Chenxi; Zhang, Gang; Ni, Zhenhua; Watanabe, K.; Taniguchi, T.; Shi, Yi; Wang, Xinran

    2012-01-01

    Strain engineered graphene has been predicted to show many interesting physics and device applications. Here we study biaxial compressive strain in graphene/hexagonal boron nitride heterostructures after thermal cycling to high temperatures likely due to their thermal expansion coefficient mismatch. The appearance of sub-micron self-supporting bubbles indicates that the strain is spatially inhomogeneous. Finite element modeling suggests that the strain is concentrated on the edges with regular nano-scale wrinkles, which could be a playground for strain engineering in graphene. Raman spectroscopy and mapping is employed to quantitatively probe the magnitude and distribution of strain. From the temperature-dependent shifts of Raman G and 2D peaks, we estimate the TEC of graphene from room temperature to above 1000K for the first time. PMID:23189242

  5. In vivo cranial bone strain and bite force in the agamid lizard Uromastyx geyri

    PubMed Central

    Porro, Laura B.; Ross, Callum F.; Iriarte-Diaz, Jose; O'Reilly, James C.; Evans, Susan E.; Fagan, Michael J.

    2014-01-01

    In vivo bone strain data are the most direct evidence of deformation and strain regimes in the vertebrate cranium during feeding and can provide important insights into skull morphology. Strain data have been collected during feeding across a wide range of mammals; in contrast, in vivo cranial bone strain data have been collected from few sauropsid taxa. Here we present bone strain data recorded from the jugal of the herbivorous agamid lizard Uromastyx geyri along with simultaneously recorded bite force. Principal and shear strain magnitudes in Uromastyx geyri were lower than cranial bone strains recorded in Alligator mississippiensis, but higher than those reported from herbivorous mammals. Our results suggest that variations in principal strain orientations in the facial skeleton are largely due to differences in feeding behavior and bite location, whereas food type has little impact on strain orientations. Furthermore, mean principal strain orientations differ between male and female Uromastyx during feeding, potentially because of sexual dimorphism in skull morphology. PMID:24577443

  6. Network of flexible capacitive strain gauges for the reconstruction of surface strain

    NASA Astrophysics Data System (ADS)

    Wu, Jingzhe; Song, Chunhui; Saleem, Hussam S.; Downey, Austin; Laflamme, Simon

    2015-05-01

    Monitoring of surface strain on mesosurfaces is a difficult task, often impeded by the lack of scalability of conventional sensing systems. A solution is to deploy large networks of flexible strain gauges, a type of large area electronics. The authors have recently proposed a soft elastomeric capacitor (SEC) as an economical skin-type solution for large-scale deployment onto mesosurfaces. The sensing principle is based on a measurable change in the sensor’s capacitance upon strain. In this paper, we study the performance of the sensor at reconstructing surface strain map and deflection shapes. A particular feature of the sensor is that it measures surface strain additively, because it is not utilized within a Wheatstone bridge configuration. An algorithm is proposed to decompose the additive in-plane strain measurements from the SEC into principal components. The algorithm consists of assuming a polynomial shape function, and deriving the strain based on Kirchhoff plate theory. A least-squares estimator (LSE) is used to minimize the error between the assumed model and the SEC signals after the enforcement of boundary conditions. Numerical simulations are conducted on a symmetric rectangular cantilever thin plate under symmetric and asymmetric static loads to demonstrate the accuracy and real-time applicability of the algorithm. The performance of the algorithm is further examined on an asymmetric cantilever laminated thin plate constituted with orthotropic materials mimicking a wind turbine blade, and subjected to a non-stationary wind load. Results from simulations show good performance of the algorithm at reconstructing the surface strain maps for both in-plane principal strain components, and that it can be applied in real time. However, its performance can be improved by strengthening assumptions on boundary conditions. The algorithm exhibits robustness in performance with respect to load and noise in signals, except when most of the sensors’ signals are

  7. Marble decay due to microcracking

    NASA Astrophysics Data System (ADS)

    Shushakova, V.; Fuller, E. R., Jr.; Heidelbach, F.; Siegesmund, S.

    2012-04-01

    An actual degradation phenomenon of marble structures, i.e., microcracking, is examined via computer simulations with a microstructure-based finite element modelling. Crack initiation and crack propagation were characterized, as well their dependence on grain- shape preferred orientation (SPO), lattice preferred orientation (LPO), grain size and grain-boundary fracture toughness. Calcite is used as an illustrative example. Results are expected to be general for myriad marble microstructures, as the thermophysical properties of various marbles do not differ that much. Three SPOs were analyzed: equiaxed grains; elongated grains and a mixture of equiaxed and elongated grains. Six LPOs were considered: a random orientation distribution function (ODF); an ODF with strong directional crystal texture generated via March Dollase fiber-texture; and four types of actual marble texture as measured on marble samples with electron back-scattered diffraction (EBSD). Two different grain sizes were analyzed: fine grains range up to 200μm and medium size grains of approximate 1mm. The fracture surface energy for the grain boundaries was chosen to be 20 % and 40 % of the fracture surface energy of a grain, so that both intergranular and transgranular fractures were possible. Simulations were performed for both heating and cooling by 50 °C in steps of 1 °C. Microcracking results were correlated with the thermoelastic responses (indicators) related to degradation. Certain combinations of SPO, LPO, grain size, and grain-boundary fracture toughness have a significant influence on the thermal-elastic response of marble. For instance, thermal stresses and elastic strain energy are a strong function of the LPO. With increasing LPO the strain energy density and the maximum principal stress decreases. With decreasing grain size and increasing LPO and SPO, the area of microcracking is smaller and microcracking commences at a higher temperature differential.

  8. [Dehydration due to "mouth broken"].

    PubMed

    Meijler, D P M; van Mossevelde, P W J; van Beek, R H T

    2012-09-01

    Two children were admitted to a medical centre due to dehydration after an oral injury and the extraction of a tooth. One child complained of "mouth broken". Dehydration is the most common water-electrolyte imbalance in children. Babies and young children are prone to dehydration due to their relatively large body surface area, the high percentage extracellular fluid, and the limited ability of the kidneys to conserve water. After the removal ofa tooth, after an oral trauma or in case of oral discomfort, a child is at greater risk of dehydration by reduced fluid and food intake due to oral pain and/or discomfort and anxiety to drink. In those cases, extra attention needs to be devoted to the intake of fluids.

  9. Dysphagia due to cervical osteophytes.

    PubMed

    Khan, Mohammad Saeed; Bansal, Meghana; Agarwal, Abhishek

    2012-05-01

    Cervical bony outgrowths or osteophytes are common and usually asymptomatic. In some cases, they may be associated with dysphagia, dysphonia, dyspnea and pulmonary aspiration. The most common causes of cervical osteophytes are osteoarthritis, ankylosing spondylitis and ankylosing hyperostosis or Diffuse Idiopathic Spinal Hyperostosis (DISH), also known as Forestier's Disease. Other causes are hypoparathyroidism, trauma, acromegaly, ochronosis and flourosis. However, while dysphagia due to osteophytes is reported in the setting of DISH, it is very rare with osteoarthritis. We report a case of a patient who developed dysphagia due to anterior cervical osteophytes in the setting of osteoarthritis.

  10. Hypercalcemia due to talc granulomatosis.

    PubMed

    Woywodt, A; Schneider, W; Goebel, U; Luft, F C

    2000-04-01

    Pulmonary disease due to talc, a group of hydrous magnesium silicates, is almost exclusively encountered after occupational exposure. One form of this rare disorder is talc granulomatosis. In varying degrees, hypercalcemia is typical of granulomatous disease but has not yet been reported in talcosis. We report the case of a former mold maker who presented with hypercalcemia. Laboratory findings indicated extra-renal 1-alpha-hydroxylation of 25-hydroxyvitamin D. Pulmonary infiltrates prompted a lung biopsy that disclosed talc granulomatosis. We suggest that talc granulomatosis should be added to the list of granulomatous disorders capable of causing hypercalcemia due to increased extra-renal 1-alpha-hydroxylation of 25-hydroxyvitamin D.

  11. Highly stretchable miniature strain sensor for large dynamic strain measurement

    DOE PAGES

    Song, Bo; Yao, Shurong; Nie, Xu; ...

    2016-01-01

    In this paper, a new type of highly stretchable strain sensor was developed to measure large strains. The sensor was based on the piezo-resistive response of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite thin films. The piezo-resistive response of CNT composite gives accurate strain measurement with high frequency response, while the ultra-soft PDMS matrix provides high flexibility and ductility for large strain measurement. Experimental results show that the CNT/PDMS sensor measures large strains (up to 8 %) with an excellent linearity and a fast frequency response. The new miniature strain sensor also exhibits much higher sensitivities than the conventional foil strain gages,more » as its gauge factor is 500 times of that of the conventional foil strain gages.« less

  12. Highly stretchable miniature strain sensor for large dynamic strain measurement

    SciTech Connect

    Song, Bo; Yao, Shurong; Nie, Xu; Yu, Xun; Blecke, Jill

    2016-01-01

    In this paper, a new type of highly stretchable strain sensor was developed to measure large strains. The sensor was based on the piezo-resistive response of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite thin films. The piezo-resistive response of CNT composite gives accurate strain measurement with high frequency response, while the ultra-soft PDMS matrix provides high flexibility and ductility for large strain measurement. Experimental results show that the CNT/PDMS sensor measures large strains (up to 8 %) with an excellent linearity and a fast frequency response. The new miniature strain sensor also exhibits much higher sensitivities than the conventional foil strain gages, as its gauge factor is 500 times of that of the conventional foil strain gages.

  13. Strain patterns and strain accumulation along plate margins

    NASA Technical Reports Server (NTRS)

    Savage, J. C.

    1978-01-01

    Observations of strain accumulation along plate margins in Japan, New Zealand, and the United States indicate that: (1) a typical maximum rate of secular strain accumulation is on the order of 0.3 ppm/a, (2) a substantial part of the strain accumulation process can be attributed to slip at depth on the major plate boundary faults, and (3) some plastic deformation in a zone 100 km or more in width is apparently involved in the strain accumulation process.

  14. Due Process Hearing Case Study

    ERIC Educational Resources Information Center

    Bateman, David F.

    2008-01-01

    Ben is a 16-year-old student who resides with his family in an unnamed School District. He is eligible for special education by reason of specific learning disability and ADHD. His parents requested a due process hearing, alleging that the District failed to provide him with a free appropriate public education (FAPE) and requesting reimbursement…

  15. Due Process Hearing Case Study

    ERIC Educational Resources Information Center

    Bateman, David F.; Jones, Marni Gail

    2010-01-01

    This article presents a due process hearing case study of a mother who contended that his son, D.J., has been denied of a free and appropriate public education (FAPE) of his School District after being suspended from school. D.J., an elementary student, had been described as hyperactive, inattentive, defiant, and often volatile. He was identified…

  16. Elephantine nose due to rhinoentomophthoromycosis.

    PubMed

    Ghorpade, Ashok; Sarma, Podila S A; Iqbal, Syed Md

    2006-01-01

    Rhinoentomophthoromycosis in an immunocompetent Indian male due to Basidiobolus species resulting in a huge (elephantine) nasal deformity, is reported. The diagnosis was done by demonstration of hyphae in direct tissue smear examination in potassium hydroxide, histopathological examination and by cultural characteristics. He showed an excellent response to oral potassium iodide solution.

  17. High temperature strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); You, Tao (Inventor)

    2011-01-01

    A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500.degree. C. A scanning electron microscopy (SEM) of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity. Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. ITO strain sensors were prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.

  18. Strained Ring Energetic Binders

    DTIC Science & Technology

    1993-08-27

    polyhomobenzvalene ( PHBV ). PHBV was not found to have the mechanical instability problems of PBV, but was still thermally unstable (Tonset - 660C, Tmax - 1090C...DISCUSSION 4 Polybenzvalene (PBV) 4 Polyhomobenzvalene ( PHBV ) 6 Chain-Transfer Studies 11 CONCLUSIONS 15 EXPERIMENTAL PROCEDURES 16 .F 4E 19 APPENDICES A...strained ring polymers similar to PBV are known. The investigation of one of these polymers, polyhomobenzvalene ( PHBV ), is also described in this report

  19. Strain Gage Signal Interpretation.

    DTIC Science & Technology

    1986-02-01

    blades and vanes in many engines have been collected, played back and examined. The engine types encompass GE’s stable of turbine engines from the small...aeromechanical engineer . 1.3 SUMMARY OF RESULTS Strain gage signals from vibrating rotor blades and vanes were collected, examined, classified, and generalized...turboprops, to turbojets and to the large high bypass turbofan engines . Test conditions include all the phases that are investigated

  20. Strain Measurement - Unidirectional.

    DTIC Science & Technology

    1983-04-20

    a ballpoint pen or a rounded piece of brass rod. If critical alignment is not necessary, gage lines may be located outside the immediate gage location...supplemented as needed by tabulated values. If the test design includes specification limits for the values, they should be included on the plots. Plots of...enough baseline before the event to allow estimation of the noise and stability. If the strain is to be correlated to specific events, the events should

  1. Production of WTC.ZI-zi rat congenic strain and its pathological and genetic analyses.

    PubMed

    Kuramoto, T; Yamasaki, K; Kondo, A; Nakajima, K; Yamada, M; Serikawa, T

    1998-04-01

    A new rat congenic strain, WTC.ZI-zi, was produced after eleven generations of backcrossing between ZI strain as a donor strain and WTC strain as an inbred partner. WTC.ZI-zi/zi homozygous rats generally exhibit more conspicuous body tremor and much earlier occurrence of flaccid paresis than the original ZI strain. The average life span of the congenic strain is approximately nine months, which is also much shorter than that of the original ZI strain. Pathological analysis of the central nervous system of the congenic strain revealed more aggravated vacuolation and hypomyelination than in the original ZI strain. Establishment of the genetic profile with microsatellite markers showed that the congenic strain was genetically almost identical to the WTC strain except for a small chromosome segment bearing the zitter gene. Analysis of markers in this region implied that the length of the donor segment was approximately 13.4 centimorgans which corresponded to 0.65% of the total genome. Thus, these results suggested that expressional alterations of zitter gene were due to replacement of the genetic background from the original ZI strain to the WTC strain. Furthermore, the WTC.ZI-zi congenic strain could provide a refined tool for the analysis of zitter mutation, because the congenic strain has a strict control strain, WTC, and the length of the donor chromosome is genetically defined.

  2. Prosthetic Valve Endocarditis and Bloodstream Infection Due to Mycobacterium chimaera

    PubMed Central

    Achermann, Yvonne; Rössle, Matthias; Hoffmann, Matthias; Deggim, Vanessa; Kuster, Stefan; Zimmermann, Dieter R.; Hombach, Michael; Hasse, Barbara

    2013-01-01

    Prosthetic valve endocarditis (PVE) due to fast-growing nontuberculous mycobacteria (NTM) has been reported anecdotally. Reports of PVE with slowly growing NTM, however, are lacking. We present here one case of PVE and one case of bloodstream infection caused by Mycobacterium chimaera. Randomly amplified polymorphic DNA (RAPD)-PCR indicated a relatedness of the two M. chimaera strains. Both patients had heart surgery 2 years apart from each other. A nosocomial link was not detected. PMID:23536407

  3. Prosthetic valve endocarditis and bloodstream infection due to Mycobacterium chimaera.

    PubMed

    Achermann, Yvonne; Rössle, Matthias; Hoffmann, Matthias; Deggim, Vanessa; Kuster, Stefan; Zimmermann, Dieter R; Bloemberg, Guido; Hombach, Michael; Hasse, Barbara

    2013-06-01

    Prosthetic valve endocarditis (PVE) due to fast-growing nontuberculous mycobacteria (NTM) has been reported anecdotally. Reports of PVE with slowly growing NTM, however, are lacking. We present here one case of PVE and one case of bloodstream infection caused by Mycobacterium chimaera. Randomly amplified polymorphic DNA (RAPD)-PCR indicated a relatedness of the two M. chimaera strains. Both patients had heart surgery 2 years apart from each other. A nosocomial link was not detected.

  4. What Are Sprains and Strains?

    MedlinePlus

    ... hands and arms a lot. Examples are gymnastics, tennis, rowing, and golf. People who play these sports sometimes strain their hand or arm. Elbow strains can also happen when playing sports. What ...

  5. Reliable strain measurement in transistor arrays by robust scanning transmission electron microscopy

    SciTech Connect

    Kim, Suhyun; Kim, Joong Jung; Jung, Younheum; Lee, Kyungwoo; Byun, Gwangsun; Hwang, KyoungHwan; Lee, Sunyoung; Lee, Kyupil

    2013-09-15

    Accurate measurement of the strain field in the channels of transistor arrays is critical for strain engineering in modern electronic devices. We applied atomic-resolution high-angle annular dark-field scanning transmission electron microscopy to quantitative measurement of the strain field in transistor arrays. The quantitative strain profile over 20 transistors was obtained with high reliability and a precision of 0.1%. The strain field was found to form homogeneously in the channels of the transistor arrays. Furthermore, strain relaxation due to the thin foil effect was quantitatively investigated for thicknesses of 35 to 275 nm.

  6. Chylothorax due to tuberculosis lymphadenitis

    PubMed Central

    Kutlu, Orkide; Demirbas, Soner; Sakin, Abdullah

    2016-01-01

    Chylothorax is a rare clinical condition characterized by high triglyceride and low cholesterol levels in milky pleural aspirate. Generally, it occurs through leakage of chyle as result of trauma or malignancy. Chylothorax due to tuberculous lymphadenitis is very rare clinical condition that has only been documented in a few cases. Although precise pathogenesis is not known, enlarged mediastinal and hilar lymph nodes are thought to be associated with opening of collateral anastomosis between thoracic duct and the azygos and intercostal veins by creating pressure on thoracic duct and cisterna chyli. Presently described is case of chylothorax thought to be due to compression from mediastinal tuberculous lymphadenitis, and which had complete remission after antituberculosis treatment. PMID:28275756

  7. Necrotizing fasciitis due to appendicitis.

    PubMed

    Groth, D; Henderson, S O

    1999-10-01

    Necrotizing fasciitis, although rare, is one of the more serious, life-threatening complications of missed acute appendicitis. Patients who are predisposed to developing necrotizing fasciitis, regardless of the cause, are typically immunocompromised. We present a case of a 49-year-old immunocompetent female whose diagnosis of acute appendicitis was missed and who subsequently developed necrotizing fasciitis of the abdominal wall and flank. She recovered 1 month after admission due to aggressive surgical and medical therapy.

  8. Molecular Epidemiology of sil Locus in Clinical Streptococcus pyogenes Strains

    PubMed Central

    Plainvert, Céline; Dinis, Márcia; Ravins, Miriam; Hanski, Emanuel; Touak, Gérald; Dmytruk, Nicolas; Fouet, Agnès

    2014-01-01

    Streptococcus pyogenes (group A Streptococcus [GAS]) causes a wide variety of diseases, ranging from mild noninvasive to severe invasive infections. Mutations in regulatory components have been implicated in the switch from colonization to invasive phenotypes. The inactivation of the sil locus, composed of six genes encoding a quorum-sensing complex, gives rise to a highly invasive strain. However, studies conducted on limited collections of GAS strains suggested that sil prevalence is around 15%; furthermore, whereas a correlation between the presence of sil and the genetic background was suggested, no link between the presence of a functional sil locus and the invasive status was assessed. We established a collection of 637 nonredundant strains covering all emm genotypes present in France and of known clinical history; 68%, 22%, and 10% were from invasive infections, noninvasive infections, and asymptomatic carriage, respectively. Among the 637 strains, 206 were sil positive. The prevalence of the sil locus varied according to the emm genotype, being present in >85% of the emm4, emm18, emm32, emm60, emm87, and emm90 strains and absent from all emm1, emm28, and emm89 strains. A random selection based on 2009 French epidemiological data indicated that 16% of GAS strains are sil positive. Moreover, due to mutations leading to truncated proteins, only 9% of GAS strains harbor a predicted functional sil system. No correlation was observed between the presence or absence of a functional sil locus and the strain invasiveness status. PMID:24671796

  9. Subsidence due to geothermal fluid withdrawal

    SciTech Connect

    Narasimhan, T. N.; Goyal, K. P.

    1984-12-01

    Single-phase and two-phase geothermal reservoirs are currently being exploited for power production in Italy, Mexico, New Zealand, the United States, and elsewhere. Vertical ground displacements of up to 4.5 m and horizontal ground displacements of up to 0.5 m have been observed at Wairakei, New Zealand, that are clearly attributable to the resource exploitation. Similarly, vertical displacements of about 0.13 m have been recorded at The Geysers, California. No significant ground displacements that are attributable to large-scale fluid production have been observed at Larderello, Italy, and Cerro Prieto, Mexico. In this paper, observations show that subsidence due to geothermal fluid production is characterized by such features as an offset of the subsidence bowl from the main area of production, time-lag between production and subsidence, and nonlinear stress-strain relationships. Several plausible conceptual models, of varying degrees of sophistication, have been proposed to explain the observed features. At present, relatively more is known about the physical mechanisms that govern subsidence than the relevant thermal mechanisms. Finally, although attempts have been made to simulate observed geothermal subsidence, the modeling efforts have been seriously limited by a lack of relevant field data needed to sufficiently characterize the complex field system.

  10. Subsidence due to geothermal fluid withdrawal

    SciTech Connect

    Narasimhan, T.N.; Goyal, K.P.

    1982-10-01

    Single-phase and two-phase geothermal reservoirs are currently being exploited for power production in Italy, Mexico, New Zealand, the U.S. and elsewhere. Vertical ground displacements of upto 4.5 m and horizontal ground displacements of up t o 0.5 m have been observed at Wairakei, New Zealand that are clearly attributable to the resource exploitation. Similarly, vertical displacements of about 0.13 m have been recorded at The Geysers, California. No significant ground displacements that are attributable to large-scale fluid production have been observed at Larderello, Italy and Cerro Prieto, Mexico. Observations show that subsidence due to geothermal fluid production is characterized by such features as an offset of the subsidence bowl from the main area of production, time-lag between production and subsidence and nonlinear stress-strain relationships. Several plausible conceptual models, of varying degrees of sophistication, have been proposed to explain the observed features. At present, relatively more is known about the physical mechanisms that govern subsidence than the relevant therma mechanisms. Although attempts have been made to simulate observed geothermal subsidence, the modeling efforts have been seriously limited by a lack of relevant field data needed to sufficiently characterize the complex field system.

  11. Disruption of ubiquitin-related genes in laboratory yeast strains enhances ethanol production during sake brewing.

    PubMed

    Wu, Hong; Watanabe, Tomoko; Araki, Yoshio; Kitagaki, Hiroshi; Akao, Takeshi; Takagi, Hiroshi; Shimoi, Hitoshi

    2009-06-01

    Sake yeast can produce high levels of ethanol in concentrated rice mash. While both sake and laboratory yeast strains belong to the species Saccharomyces cerevisiae, the laboratory strains produce much less ethanol. This disparity in fermentation activity may be due to the strains' different responses to environmental stresses, including ethanol accumulation. To obtain more insight into the stress response of yeast cells under sake brewing conditions, we carried out small-scale sake brewing tests using laboratory yeast strains disrupted in specific stress-related genes. Surprisingly, yeast strains with disrupted ubiquitin-related genes produced more ethanol than the parental strain during sake brewing. The elevated fermentation ability conferred by disruption of the ubiquitin-coding gene UBI4 was confined to laboratory strains, and the ubi4 disruptant of a sake yeast strain did not demonstrate a comparable increase in ethanol production. These findings suggest different roles for ubiquitin in sake and laboratory yeast strains.

  12. Genotypic comparison of Pantoea agglomerans plant and clinical strains

    PubMed Central

    2009-01-01

    Background Pantoea agglomerans strains are among the most promising biocontrol agents for a variety of bacterial and fungal plant diseases, particularly fire blight of apple and pear. However, commercial registration of P. agglomerans biocontrol products is hampered because this species is currently listed as a biosafety level 2 (BL2) organism due to clinical reports as an opportunistic human pathogen. This study compares plant-origin and clinical strains in a search for discriminating genotypic/phenotypic markers using multi-locus phylogenetic analysis and fluorescent amplified fragment length polymorphisms (fAFLP) fingerprinting. Results Majority of the clinical isolates from culture collections were found to be improperly designated as P. agglomerans after sequence analysis. The frequent taxonomic rearrangements underwent by the Enterobacter agglomerans/Erwinia herbicola complex may be a major problem in assessing clinical associations within P. agglomerans. In the P. agglomerans sensu stricto (in the stricter sense) group, there was no discrete clustering of clinical/biocontrol strains and no marker was identified that was uniquely associated to clinical strains. A putative biocontrol-specific fAFLP marker was identified only in biocontrol strains. The partial ORF located in this band corresponded to an ABC transporter that was found in all P. agglomerans strains. Conclusion Taxonomic mischaracterization was identified as a major problem with P. agglomerans, and current techniques removed a majority of clinical strains from this species. Although clear discrimination between P. agglomerans plant and clinical strains was not obtained with phylogenetic analysis, a single marker characteristic of biocontrol strains was identified which may be of use in strain biosafety determinations. In addition, the lack of Koch's postulate fulfilment, rare retention of clinical strains for subsequent confirmation, and the polymicrobial nature of P. agglomerans clinical reports

  13. Endocarditis due to Kingella kingae.

    PubMed

    Odum, L; Jensen, K T; Slotsbjerg, T D

    1984-06-01

    Four cases of endocarditis due to Kingella kingae are described in compromised patients. All had primary heart disease, and two had systemic lupus erythematosis and congenital heart defect respectively, in addition. Confirmation of Kingella kingae was made in one case at autopsy. The literature on 11 cases of endocarditis, 2 bacteremia, 4 osteomyelitis, 5 septic arthritis and 1 intervertebral disc infection, all caused by Kingella kingae, is reviewed. Our findings confirm that the organism is of low pathogenicity. Children may be predisposed to infection with Kingella kingae.

  14. Anaphylaxis due to head injury.

    PubMed

    Bruner, Heather C; Bruner, David I

    2015-05-01

    Both anaphylaxis and head injury are often seen in the emergency department, but they are rarely seen in combination. We present a case of a 30-year-old woman who presented with anaphylaxis with urticaria and angioedema following a minor head injury. The patient responded well to intramuscular epinephrine without further complications or airway compromise. Prior case reports have reported angioedema from hereditary angioedema during dental procedures and maxillofacial surgery, but there have not been any cases of first-time angioedema or anaphylaxis due to head injury.

  15. Anaphylaxis Due to Head Injury

    PubMed Central

    Bruner, Heather C.; Bruner, David I.

    2015-01-01

    Both anaphylaxis and head injury are often seen in the emergency department, but they are rarely seen in combination. We present a case of a 30-year-old woman who presented with anaphylaxis with urticaria and angioedema following a minor head injury. The patient responded well to intramuscular epinephrine without further complications or airway compromise. Prior case reports have reported angioedema from hereditary angioedema during dental procedures and maxillofacial surgery, but there have not been any cases of first-time angioedema or anaphylaxis due to head injury. PMID:25987924

  16. The relationship between strain geometry and geometrically necessary dislocations

    NASA Astrophysics Data System (ADS)

    Hansen, Lars; Wallis, David

    2016-04-01

    The kinematics of past deformations are often a primary goal in structural analyses of strained rocks. Details of the strain geometry, in particular, can help distinguish hypotheses about large-scale tectonic phenomena. Microstructural indicators of strain geometry have been heavily utilized to investigate large-scale kinematics. However, many of the existing techniques require structures for which the initial morphology is known, and those structures must undergo the same deformation as imposed macroscopically. Many deformed rocks do not exhibit such convenient features, and therefore the strain geometry is often difficult (if not impossible) to ascertain. Alternatively, crystallographic textures contain information about the strain geometry, but the influence of strain geometry can be difficult to separate from other environmental factors that might affect slip system activity and therefore the textural evolution. Here we explore the ability for geometrically necessary dislocations to record information about the deformation geometry. It is well known that crystallographic slip due to the motion of dislocations yields macroscopic plastic strain, and the mathematics are established to relate dislocation glide on multiple slip systems to the strain tensor of a crystal. This theoretical description generally assumes that dislocations propagate across the entire crystal. However, at any point during the deformation, dislocations are present that have not fully transected the crystal, existing either as free dislocations or as dislocations organized into substructures like subgrain boundaries. These dislocations can remain in the lattice after deformation if the crystal is quenched sufficiently fast, and we hypothesize that this residual dislocation population can be linked to the plastic strain geometry in a quantitative manner. To test this hypothesis, we use high-resolution electron backscatter diffraction to measure lattice curvatures in experimentally deformed

  17. Strain analysis of a chiral smectic-A elastomer.

    PubMed

    Spillmann, Christopher M; Konnert, John H; Adams, James M; Deschamps, Jeffrey R; Naciri, Jawad; Ratna, Banahalli R

    2010-09-01

    We present a detailed analysis of the molecular packing of a strained liquid crystal elastomer composed of chiral mesogens in the smectic-A phase. X-ray diffraction patterns of the elastomer collected over a range of orientations with respect to the x-ray beam were used to reconstruct the three-dimensional scattering intensity as a function of tensile strain. We show that the smectic domain order is preserved in these strained elastomers. Changes in the intensity within a given scattering plane are due to reorientation, and not loss, of the molecular order in directions orthogonal to the applied strain. Incorporating the physical parameters of the elastomer, a nonlinear elastic model is presented to describe the rotation of the smectic-layered domains under strain, thus providing a fundamental analysis to the mechanical response of these unique materials.

  18. Tuning surface Dirac valleys by strain in topological crystalline insulators

    NASA Astrophysics Data System (ADS)

    Zhao, Lu; Wang, Jianfeng; Gu, Bing-Lin; Duan, Wenhui

    2015-05-01

    A topological crystalline insulator has an even number of Dirac cones (i.e., multiple valleys) in its surface band structure, thus potentially leading to valleytronic applications such as graphene. Using the density-functional-theory method, we systematically investigate the strain-induced evolution of topological surface states on the SnTe(111) surface. Our results show that compressive strain can shift the Dirac cones at the Γ ¯ and M ¯ valleys to different extents (even oppositely) in energy, while the tensile strain can induce different band gaps at the valleys due to the enhanced penetration depths of surface states. Exploiting a strain-induced nanostructure with well-defined edges on the (111) surface, we demonstrate strong valley-selective filtering for massless Dirac fermions by dynamically applying local external pressure. Our findings may pave the way for strain-engineered valley-resolved manipulation of Dirac fermions with high tunability and scalability.

  19. Development of a high temperature static strain sensor

    NASA Technical Reports Server (NTRS)

    Hulse, Charles O.; Bailey, Richard S.; Grant, Howard P.

    1986-01-01

    The goal of this program is to develop an electrical resistance strain gage system which will accurately measure the static strains of superalloy blades and vanes in gas turbine engines running on a test stand. Accurate knowledge of these strains is essential to reaching the goals of the HOST program in the selection and experimental verification of the various theoretical models developed to understand and improve the performance of these engines. The specific objective is to develop a complete system capable of making strain measurements of up to + or - 10 percent of full scale during a 50 hour period at temperatures as high as 1250 K. In addition to survival and stability, attaining a low temperature coefficient of resistance, of the order of 20 ppm/K or less, was a major goal. This requirement arises from the presently unavoidable uncertainties in measurement of the exact temperatures inside gas turbines for use in making corrections for apparent strain due to temperature.

  20. Strain relaxation in graphene grown by chemical vapor deposition

    SciTech Connect

    Troppenz, Gerald V. Gluba, Marc A.; Kraft, Marco; Rappich, Jörg; Nickel, Norbert H.

    2013-12-07

    The growth of single layer graphene by chemical vapor deposition on polycrystalline Cu substrates induces large internal biaxial compressive strain due to thermal expansion mismatch. Raman backscattering spectroscopy and atomic force microscopy were used to study the strain relaxation during and after the transfer process from Cu foil to SiO{sub 2}. Interestingly, the growth of graphene results in a pronounced ripple structure on the Cu substrate that is indicative of strain relaxation of about 0.76% during the cooling from the growth temperature. Removing graphene from the Cu substrates and transferring it to SiO{sub 2} results in a shift of the 2D phonon line by 27 cm{sup −1} to lower frequencies. This translates into additional strain relaxation. The influence of the processing steps, used etching solution and solvents on strain, is investigated.

  1. Decoherence due to Scattering Atoms

    NASA Astrophysics Data System (ADS)

    Uys, Hermann; Perreault, John; Cronin, Alex

    2004-05-01

    Coherent manipulation of a quantum system is difficult because of uncontrolled interactions with the system's environment. The study of decoherence so introduced is important for progress in quantum mechanical engineering, and for understanding the transition from quantum to classical behavior. We have observed loss of fringe contrast in a Mach-Zhender atom interferometer due to scattering background gas atoms and propose that this might be interpreted as quantum decoherence. Progress will be reported on the use of a general model of decoherence incorporating a semi-classical picture of atom scattering to explain the contrast loss [1]. A formal analogy is made to decoherence due to scattering photons from atoms in an interferometer [2]. [1] S.M. Tan, D.F. Waals, ``Loss of coherence in interferometry", Phys. Rev. A 47 p.4663 (1993) [2] D.A. Kokorowski, A.D. Cronin, T.D. Roberts, and D.E. Pritchard, ``From single- to multiple-photon decoherence in an atom interferometer", Phys. Rev. Lett. 86 p. 2191 (2001)

  2. Thermal strain analysis of optic fiber sensors.

    PubMed

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2013-01-31

    An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  3. Quality Control On Strained Semiconductor Devices

    SciTech Connect

    Dommann, Alex; Neels, Antonia

    2010-11-24

    New semiconductor devices are based very often on strained silicon which promises to squeeze more device performance out of current devices. With strained silicon it is possible to get the same device performance using less power. The technique is using strain as a 'design element' for silicon to improve the device performance and has become a hot topic in semiconductor research in the past years. However in the same time topics like 'System in Package'(SiP) on thin wafers are getting more and more important. The chips of thin wafers in advanced packaging are extremely sensitive to induced stresses due to packaging issues. If we are using now strain as a design element for improving device performance we increase the sensitivity again and therefore also the risk of aging of such SiP's. High Resolution X-ray diffraction (HRXRD) techniques such as Rocking Curves (RC's) and Reciprocal Space Mapping (RSM) are therefore very powerful tools to study the stresses in packaged devices.

  4. High strain-rate magnetoelasticity in Galfenol

    NASA Astrophysics Data System (ADS)

    Domann, J. P.; Loeffler, C. M.; Martin, B. E.; Carman, G. P.

    2015-09-01

    This paper presents the experimental measurements of a highly magnetoelastic material (Galfenol) under impact loading. A Split-Hopkinson Pressure Bar was used to generate compressive stress up to 275 MPa at strain rates of either 20/s or 33/s while measuring the stress-strain response and change in magnetic flux density due to magnetoelastic coupling. The average Young's modulus (44.85 GPa) was invariant to strain rate, with instantaneous stiffness ranging from 25 to 55 GPa. A lumped parameters model simulated the measured pickup coil voltages in response to an applied stress pulse. Fitting the model to the experimental data provided the average piezomagnetic coefficient and relative permeability as functions of field strength. The model suggests magnetoelastic coupling is primarily insensitive to strain rates as high as 33/s. Additionally, the lumped parameters model was used to investigate magnetoelastic transducers as potential pulsed power sources. Results show that Galfenol can generate large quantities of instantaneous power (80 MW/m3 ), comparable to explosively driven ferromagnetic pulse generators (500 MW/m3 ). However, this process is much more efficient and can be cyclically carried out in the linear elastic range of the material, in stark contrast with explosively driven pulsed power generators.

  5. Vortex Evolution due to Straining: A Mechanism for Dominance of Strong, Interior Anticyclones

    DTIC Science & Technology

    2006-06-01

    questions is a rotating, conservative, Shallow-water model with Asymmetric and Gradient-wind Balance approximations. The controlling mechanisms are vortex...Red Spot of Jupiter (figure 1). Coherent vortices have also been found in computational turbulence studies of initially randomly distributed...Many studies have noted the preferential existence of anticyclones both in nature (e.g., atmospheric blocking anticylones and submesoscale coherent

  6. Shear Stress at a Film-Substrate Interface Due to Mismatch Strain,

    DTIC Science & Technology

    1988-01-01

    situation provides useful results on the edge effect for very wide films, it provides no basis for assessing the influence of lateral dimension of the film...the edge stress concentration is more severe than it would be in a more complete description of the edge effect . Indeed, for points very close to the

  7. Forming patterns and mechanical properties of austenitic chromium-nickel steel due to strain aging

    NASA Astrophysics Data System (ADS)

    Kamyshanchenko, N. V.; Krasilnikov, V. V.; Nikulin, I. S.; Gal'tsev, A. V.; Belenko, V. A.; Gal'tseva, I. N.

    2016-02-01

    The work presents the results of studies of forming patterns and mechanical properties of martensite transformation, found in the chromium-nickel steels of 08X18H10T grade, subjected to pre-heat treatment followed by deformation aging. Internal energy state is determined by using acoustic emission. The observed patterns improve the mechanical parameters of steels quenched and plastically deformed at low temperature and then subjected to temper under load in the optimum temperature being associated with obtaining a more stable condition of the structure through the processes of relaxation of internal stresses, high dispersion and uniform distribution of carbides and intermetallic particles, increasing the density of dislocations as well as through other processes occurring during deformation aging martensite. Start your abstract here...

  8. Errors Due to Counting Statistics in the Triaxial Strain (Stress) Tensor Determined by Diffraction.

    DTIC Science & Technology

    2014-09-26

    Distribution of this docimnt Reproduction in whole or in part in unlimited is permitted for any purpose of the United States Government L" __j a m...1973). 3) S. Taira, T. Abe and T. Ehiro, X-ray Study of Surface Residual Stress Produced in Fatigue Process of Annealed Metals, Bull J.S.M.E., 12:53

  9. Repetitive strain injury.

    PubMed

    van Tulder, Maurits; Malmivaara, Antti; Koes, Bart

    2007-05-26

    Repetitive strain injury remains a controversial topic. The term repetitive strain injury includes specific disorders such as carpal tunnel syndrome, cubital tunnel syndrome, Guyon canal syndrome, lateral epicondylitis, and tendonitis of the wrist or hand. The diagnosis is usually made on the basis of history and clinical examination. Large high-quality studies using newer imaging techniques, such as MRI and ultrasonography are few. Consequently, the role of such imaging in diagnosis of upper limb disorders remains unclear. In many cases, no specific diagnosis can be established and complaints are labelled as non-specific. Little is known about the effectiveness of treatment options for upper limb disorders. Strong evidence for any intervention is scarce and the effect, if any, is mainly short-term pain relief. Exercise is beneficial for non-specific upper limb disorders. Immobilising hand braces and open carpal tunnel surgery release are beneficial for carpal tunnel syndrome, and topical and oral non-steroidal anti-inflammatory drugs, and corticosteroid injections are helpful for lateral epicondylitis. Exercise is probably beneficial for neck pain, as are corticosteroid injections and exercise for shoulder pain. Although upper limb disorders occur frequently in the working population, most trials have not exclusively included a working population or assessed effects on work-related outcomes. Further high-quality trials should aim to include sufficient sample sizes, working populations, and work-related outcomes.

  10. Probing Impulsive Strain Propagation with X-Ray Pulses

    SciTech Connect

    Reis, D. A.; DeCamp, M. F.; Bucksbaum, P. H.; Clarke, R.; Dufresne, E.; Hertlein, M.; Merlin, R.; Falcone, R.; Kapteyn, H.; Murnane, M. M.

    2001-04-02

    Pump-probe time-resolved x-ray diffraction of allowed and nearly forbidden reflections in InSb is used to follow the propagation of a coherent acoustic pulse generated by ultrafast laser excitation. The surface and bulk components of the strain could be simultaneously measured due to the large x-ray penetration depth. Comparison of the experimental data with dynamical diffraction simulations suggests that the conventional model for impulsively generated strain underestimates the partitioning of energy into coherent modes.

  11. Probing Impulsive Strain Propagation with X-Ray Pulses

    NASA Astrophysics Data System (ADS)

    Reis, D. A.; Decamp, M. F.; Bucksbaum, P. H.; Clarke, R.; Dufresne, E.; Hertlein, M.; Merlin, R.; Falcone, R.; Kapteyn, H.; Murnane, M. M.; Larsson, J.; Missalla, Th.; Wark, J. S.

    2001-04-01

    Pump-probe time-resolved x-ray diffraction of allowed and nearly forbidden reflections in InSb is used to follow the propagation of a coherent acoustic pulse generated by ultrafast laser excitation. The surface and bulk components of the strain could be simultaneously measured due to the large x-ray penetration depth. Comparison of the experimental data with dynamical diffraction simulations suggests that the conventional model for impulsively generated strain underestimates the partitioning of energy into coherent modes.

  12. Strain mapping on gold thin film buckling and siliconblistering

    SciTech Connect

    Goudeau, P.; Tamura, N.; Parry, G.; Colin, J.; Coupeau, C.; Cleymand, F.; Padmore, H.

    2005-09-01

    Stress/Strain fields associated with thin film buckling induced by compressive stresses or blistering due to the presence of gas bubbles underneath single crystal surfaces are difficult to measure owing to the microscale dimensions of these structures. In this work, we show that micro Scanning X-ray diffraction is a well suited technique for mapping the strain/stress tensor of these damaged structures.

  13. Inductance due to spin current

    SciTech Connect

    Chen, Wei

    2014-03-21

    The inductance of spintronic devices that transport charge neutral spin currents is discussed. It is known that in a media that contains charge neutral spins, a time-varying electric field induces a spin current. We show that since the spin current itself produces an electric field, this implies existence of inductance and electromotive force when the spin current changes with time. The relations between the electromotive force and the corresponding flux, which is a vector calculated by the cross product of electric field and the trajectory of the device, are clarified. The relativistic origin generally renders an extremely small inductance, which indicates the advantage of spin current in building low inductance devices. The same argument also explains the inductance due to electric dipole current and applies to physical dipoles consist of polarized bound charges.

  14. [Infections due to Mycobacterium simiae].

    PubMed

    García-Martos, Pedro; García-Agudo, Lidia; González-Moya, Enrique; Galán, Fátima; Rodríguez-Iglesias, Manuel

    2015-10-01

    Mycobacterium simiae is a slow-growing photochromogenic environmental mycobacterium, first described in 1965. Rarely associated with human infections, possibly due to its limited pathogenicity, it mainly produces lung infection in immunocompetent elderly patients with underlying lung disease, and in disseminated infections in immunosuppressed young patients with AIDS. A microbiological culture is needed to confirm the clinical suspicion, and genetic sequencing techniques are essential to correctly identify the species. Treating M. simiae infections is complicated, owing to the multiple resistance to tuberculous drugs and the lack of correlation between in vitro susceptibility data and in vivo response. Proper treatment is yet to be defined, but must include clarithromycin combined with other antimicrobials such as moxifloxacin and cotrimoxazole. It is possible that M. simiae infections are undiagnosed.

  15. Collisional Aggregation Due to Turbulence

    NASA Astrophysics Data System (ADS)

    Pumir, Alain; Wilkinson, Michael

    2016-03-01

    Collisions between particles suspended in a fluid play an important role in many physical processes. As an example, collisions of microscopic water droplets in clouds are a necessary step in the production of macroscopic raindrops. Collisions of dust grains are also conjectured to be important for planet formation in the gas surrounding young stars and to play a role in the dynamics of sand storms. In these processes, collisions are favored by fast turbulent motions. Here we review recent advances in the understanding of collisional aggregation due to turbulence. We discuss the role of fractal clustering of particles and caustic singularities of their velocities. We also discuss limitations of the Smoluchowski equation for modeling such processes. These advances lead to a semiquantitative understanding on the influence of turbulence on collision rates and point to deficiencies in the current understanding of rainfall and planet formation.

  16. Thermal conductivity of graphene mediated by strain and size

    DOE PAGES

    Kuang, Youdi; Shi, Sanqiang; Wang, Xinjiang; ...

    2016-06-09

    Based on first-principles calculations and full iterative solution of the linearized Boltzmann–Peierls transport equation for phonons, we systematically investigate effects of strain, size and temperature on the thermal conductivity k of suspended graphene. The calculated size-dependent and temperature-dependent k for finite samples agree well with experimental data. The results show that, contrast to the convergent room-temperature k = 5450 W/m-K of unstrained graphene at a sample size ~8 cm, k of strained graphene diverges with increasing the sample size even at high temperature. Out-of-plane acoustic phonons are responsible for the significant size effect in unstrained and strained graphene due tomore » their ultralong mean free path and acoustic phonons with wavelength smaller than 10 nm contribute 80% to the intrinsic room temperature k of unstrained graphene. Tensile strain hardens the flexural modes and increases their lifetimes, causing interesting dependence of k on sample size and strain due to the competition between boundary scattering and intrinsic phonon–phonon scattering. k of graphene can be tuned within a large range by strain for the size larger than 500 μm. These findings shed light on the nature of thermal transport in two-dimensional materials and may guide predicting and engineering k of graphene by varying strain and size.« less

  17. Thermal conductivity of graphene mediated by strain and size

    SciTech Connect

    Kuang, Youdi; Shi, Sanqiang; Wang, Xinjiang; Huang, Baoling; Lindsay, Lucas

    2016-06-09

    Based on first-principles calculations and full iterative solution of the linearized Boltzmann–Peierls transport equation for phonons, we systematically investigate effects of strain, size and temperature on the thermal conductivity k of suspended graphene. The calculated size-dependent and temperature-dependent k for finite samples agree well with experimental data. The results show that, contrast to the convergent room-temperature k = 5450 W/m-K of unstrained graphene at a sample size ~8 cm, k of strained graphene diverges with increasing the sample size even at high temperature. Out-of-plane acoustic phonons are responsible for the significant size effect in unstrained and strained graphene due to their ultralong mean free path and acoustic phonons with wavelength smaller than 10 nm contribute 80% to the intrinsic room temperature k of unstrained graphene. Tensile strain hardens the flexural modes and increases their lifetimes, causing interesting dependence of k on sample size and strain due to the competition between boundary scattering and intrinsic phonon–phonon scattering. k of graphene can be tuned within a large range by strain for the size larger than 500 μm. These findings shed light on the nature of thermal transport in two-dimensional materials and may guide predicting and engineering k of graphene by varying strain and size.

  18. Bicrystals with strain gradient effects

    SciTech Connect

    Shu, J.Y.

    1997-01-09

    Boundary between two perfectly bonded single crystals plays an important role in determining the deformation of the bicrystals. This work addresses the role of the grain boundary by considering the elevated hardening of a slip system due to a slip gradient. The slip gradients are associated with geometrically necessary dislocations and their effects become pronounced when a representative length scale of the deformation field is comparable to the dominant microstructural length scale of a material. A new rate-dependent crystal plasticity theory is presented and has been implemented within the finite element method framework. A planar bicrystal under uniform in-plane loading is studied using the new crystal theory. The strain is found to be continuous but nonuniform within a boundary layer around the interface. The lattice rotation is also nonuniform within the boundary layer. The width of the layer is determined by the misorientation of the grains, the hardening of slip systems, and most importantly by the characteristic material length scales. The overall yield strength of the bicrystal is also obtained. A significant grain-size dependence of the yield strength, the Hall- Petch effect is predicted.

  19. Surface-state spin textures in strained bulk HgTe: Strain-induced topological phase transitions

    NASA Astrophysics Data System (ADS)

    Kirtschig, Frank; van den Brink, Jeroen; Ortix, Carmine

    2016-12-01

    The opening of a band gap due to compressive uniaxial strain renders bulk HgTe a strong three-dimensional topological insulator with protected gapless surface states at any surface. By employing a six-band k .p model, we determine the spin textures of the topological surface states of bulk HgTe uniaxially strained along the (100 ) direction. We show that at the (010 ) and (001 ) surfaces, an increase in the strain magnitude triggers a topological phase transition where the winding number of the surface-state spin texture is flipped while the four topological invariants characterizing the bulk band structure of the material are unchanged.

  20. Influence of Lysobacter enzymogenes Strain C3 on Nematodes

    PubMed Central

    Chen, J.; Moore, W. H.; Yuen, G. Y.; Kobayashi, D.; Caswell-Chen, E. P.

    2006-01-01

    Chitinolytic microflora may contribute to biological control of plant-parasitic nematodes by causing decreased egg viability through degradation of egg shells. Here, the influence of Lysobacter enzymogenes strain C3 on Caenorhabditis elegans, Heterodera schachtii, Meloidogyne javanica, Pratylenchus penetrans, and Aphelenchoides fragariae is described. Exposure of C. elegans to L. enzymogenes strain C3 on agar resulted in almost complete elimination of egg production and death of 94% of hatched juveniles after 2 d. Hatch of H. schachtii eggs was about 50% on a lawn of L. enzymogenes strain C3 on agar as compared to 80% on a lawn of E. coli. Juveniles that hatched on a lawn of L. enzymogenes strain C3 on agar died due to disintegration of the cuticle and body contents. Meloidogyne javanica juveniles died after 4 d exposure to a 7-d-old chitin broth culture of L. enzymogenes strain C3. Immersion of A. fragariae, M. javanica, and P. penetrans juveniles and adults in a nutrient broth culture of L. enzymogenes strain C3 led to rapid death and disintegration of the nematodes. Upon exposure to L. enzymogenes strain C3 cultures in nutrient broth, H. schachtii juveniles were rapidly immobilized and then lysed after three days. The death and disintegration of the tested nematodes suggests that toxins and enzymes produced by this strain are active against a range of nematode species. PMID:19259452

  1. First report of an infant botulism case due to Clostridium botulinum type Af.

    PubMed

    de Jong, Laura I T; Fernández, Rafael A; Pareja, Virtudes; Giaroli, Gabriel; Guidarelli, Sergio R; Dykes, Janet K; Lúquez, Carolina

    2015-02-01

    Most infant botulism cases worldwide are due to botulinum toxin types A and B. Rarely, Clostridium botulinum strains that produce two serotypes (Ab, Ba, and Bf) have also been isolated from infant botulism cases. This is the first reported case of infant botulism due to C. botulinum type Af worldwide.

  2. Strain Pattern in Supercooled Liquids

    NASA Astrophysics Data System (ADS)

    Illing, Bernd; Fritschi, Sebastian; Hajnal, David; Klix, Christian; Keim, Peter; Fuchs, Matthias

    2016-11-01

    Investigations of strain correlations at the glass transition reveal unexpected phenomena. The shear strain fluctuations show an Eshelby-strain pattern [˜cos (4 θ ) /r2 ], characteristic of elastic response, even in liquids, at long times. We address this using a mode-coupling theory for the strain fluctuations in supercooled liquids and data from both video microscopy of a two-dimensional colloidal glass former and simulations of Brownian hard disks. We show that the long-ranged and long-lived strain signatures follow a scaling law valid close to the glass transition. For large enough viscosities, the Eshelby-strain pattern is visible even on time scales longer than the structural relaxation time τ and after the shear modulus has relaxed to zero.

  3. Searching for Strain Transients in PBO data

    NASA Astrophysics Data System (ADS)

    Wei, M.; McGuire, J. J.; Richardson, E.; Kraft, R. L.; Hardwig, M. D.

    2011-12-01

    We applied a recently developed strain anomaly detector, the Network Stain Filter [Ohtani et al., 2010], to the continuous GPS datasets from the PBO in Alaska and Salton Trough. The strategy of the filter is to find spatially and temporally coherent signals by processing data from the entire network simultaneously. Compared to previous Network Inversion Filter [Segall and Matthews, 1997], the new detector does not require the knowledge of potential sources, which can be either unknown and/or very numerous in a large tectonically active area. At Alaska, we find a strain anomaly between Kodiak Island and Kenai Peninsula that began in early 2010. There are earthquakes that are likely related to the strain anomaly. The physical interpretation of the strain anomaly is still in progress. The secular motion since 2006 that PBO recorded is consistent with a model that consist of two locked patches on Kodiak Island and Kenai Peninsula and a creeping patch near Cook Inlet as determined earlier by Zweck et al. [2002]. Seasonal signals dominate in the data and are highly correlated between stations in the horizontal components. The reason for this correlation in seasonal term azimuths between stations is not clear. At Salton Trough, the post-seismic deformation of the 2010 Mw 7.2 El Mayor Earthquake dominates the transient signals. The maximum post-seismic slip recorded by the GPS is 23 mm during 1.5 years after the earthquake (Site ID P494). Additionally, we are exploring using InSAR data as a complimentary method for detecting strain anomaly in areas with shallow sources, such as in the Salton Trough. A creep event on the Superstition Hills Fault in October 2006 has been observed by InSAR but missed by nearby GPS stations due to low amplitude at the location [Wei et al., 2009].

  4. Colloid straining within saturated heterogeneous porous media.

    PubMed

    Porubcan, Alexis A; Xu, Shangping

    2011-02-01

    The transport of 0.46 μm, 2.94 μm, 5.1 μm and 6.06 μm latex particles in heterogeneous porous media prepared from the mixing of 0.78 mm, 0.46 mm and 0.23 mm quartz sands was investigated through column transport experiments. It was observed that the 0.46 μm particles traveled conservatively within the heterogeneous porous media, suggesting that under the experimental conditions employed in this research the strong repulsive interactions between the negatively charged latex particles and the clean quartz sands led to minimal colloid immobilization due to physicochemical filtration. The immobilization of the 2.94 μm, 5.1 μm and 6.06 μm latex particles was thus attributed to colloid straining. Experimental results showed that the straining of colloidal particles within heterogeneous sand mixtures increased when the fraction of finer sands increased. The mathematical model that was developed and tested based on results obtained using uniform sands (Xu et al., 2006) was found to be able to describe colloid straining within heterogeneous porous media. Examination of the relationship between the best-fit values of the clean-bed straining rate coefficients (k(0)) and the ratio of colloid diameter (d(p)) and sand grain size (d(g)) indicated that when number-average sizes were used to represent the size of the heterogeneous porous media, there existed a consistent relationship for both uniform sands and heterogeneous sand mixtures. Similarly, the use of the number-averaged sizes for the heterogeneous porous media produced a uniform relationship between the colloid straining capacity term (λ) and the ratio of d(p)/d(g) for all the sand treatments.

  5. Hydrogen production from microbial strains

    DOEpatents

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  6. Strain relaxation mechanisms in compressively strained thin SiGe-on-insulator films grown by selective Si oxidation

    NASA Astrophysics Data System (ADS)

    Gunji, Marika; Marshall, Ann F.; McIntyre, Paul C.

    2011-01-01

    We report on strain relaxation mechanisms in highly compressive-strained (0.67%-2.33% biaxial strain), thin SiGe-on-insulator (SGOI) structures with Ge atomic fraction ranging from 0.18 to 0.81. SGOI layers (8.7-75 nm thickness) were fabricated by selective oxidization of Si from compressively strained SiGe films epitaxially grown on single crystalline Si-on-insulator (SOI) layers. During high temperature oxidation annealing, strain relaxation occurred due to both intrinsic stacking fault (SF) formation and biaxial stress-driven buckling of the SiGe layers through viscous flow of the overlying and underlying SiO2 layers. Transmission electron microscopy (TEM) and x-ray diffraction were performed to confirm the simultaneous occurrence of these two strain relaxation mechanisms. The results indicate that ˜30 % of the observed strain relaxation can be attributed to formation of intrinsic SFs and the remaining strain relaxation to stress-driven buckling of the SiGe layers. In addition, cross-sectional TEM images show that some of the SFs and layer buckling roughness appears to be spatially correlated.

  7. Otomycosis due to filamentous fungi.

    PubMed

    García-Agudo, Lidia; Aznar-Marín, Pilar; Galán-Sánchez, Fátima; García-Martos, Pedro; Marín-Casanova, Pilar; Rodríguez-Iglesias, Manuel

    2011-10-01

    Otomycosis is common throughout the world but barely studied in Spain. Our objective was to determine the microbiological and epidemiological characteristics of this pathology in Cadiz (Spain) between 2005 and 2010. Samples from patients with suspicion of otomycosis underwent a direct microscopic examination and culture on different media for fungi and bacteria. Mycological cultures were incubated at 30°C for at least seven days. Identification of fungi was based on colonial morphology and microscopic examination of fungal structure. From a total of 2,633 samples, microbial growth was present in 1,375 (52.2%) and fungal isolation in 390 (28.4%). We identified 228 yeasts and 184 filamentous fungi (13.4% of positive cultures and 47.2% of otomycosis), associated with yeasts in 22 cases (5.6%). The most frequent species were Aspergillus flavus (42.4%), A. niger (35.9%), A. fumigatus (12.5%), A. candidus (7.1%), A. terreus (1.6%), and Paecilomyces variotii (0.5%). Infection was predominant in men (54.9%) and patients beyond 55 years old (46.8%). The most common clinical symptoms were itching (98.9%), otalgia (59.3%), and hypoacusis (56.0%). Fall season reported the lowest number of cases (20.1%). Incidence of otomycosis and fungi producing otomycosis vary within the distinct geographical areas. In Cadiz, this infection is endemic due to warm temperatures, high humidity, sea bathing, and wind, which contributes to disseminate the conidia. Despite Aspergillus niger has been reported as the main causative agent, A. flavus is predominant in Cadiz. Although infection is usually detected in warm months, we observed a homogeneous occurrence of otomycosis in almost all the seasons.

  8. Silicon Germanium Strained Layers and Heterostructures

    NASA Astrophysics Data System (ADS)

    Willander, M.; Nur, O.; Jain, S. C.

    2004-01-01

    The integration of strained-Si1 xGex into Si technology has enhanced the performance and extended the functionality of Si based circuits. The improvement of device performance is observed in both AC as well as DC characteristics of these devices. The category of such devices includes field effect as well as bipolar families. Speed performance in some based circuits has reached limits previously dominated by III-V heterostructures based devices. In addition, for some optoelectronics applications including photodetectors it is now possible to easily integrate strained-Si1 xGex based optical devices into standard Silicon technology. The impact of integrating strained and relaxed Si1 xGex alloys into Si technology is important. It has lead to stimulate Si research as well as offers easy options for performances that requires very complicated and costly process if pure Si has to be used. In this paper we start by discussing the strain and stability of Si1 xGex alloys. The origin and the process responsible for transient enhanced diffusion (TED) in highly doped Si containing layers will be mentioned. Due to the importance of TED for thin highly doped Boron strained-Si1 xGex layers and its degrading consequences, possible suppression design methods will be presented. Quantum well pchannel MOSFETs (QW-PMOSFETs) based on thin buried QW are solution to the low speed and weak current derivability. Different aspects of designing these devices for a better performance are briefly reviewed. Other FETs based on tensile strained Si on relaxed Si1 xGex for n-channel and modulation doped field effect transistors (MODFETs) showed excellent performance. Record AC performance well above 200GHz for fmax is already observed and this record is expected to increase in the coming years. Heterojunction bipolar transistors (HPTs) with thin strained-Si1 xGex highly doped base have lead to optimize the performance of the bipolar technology for many applications easily. The strategies of design

  9. Strain Dependence of Photoluminescense of Individual Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Nikolaev, Pavel N.; Leeuw, Tonya K.; Tsyboulski, Dmitri A.; Bachilo, Sergei M.; Weisman, Bruce; Arepalli, Sivaram

    2007-01-01

    We have investigated strain dependence of photoluminescense (PL) spectra of single wall carbon nanotubes (SWNT). Nanotubes were sparsely dispersed in a thin PMMA film applied to acrylic bar, and strained in both compression and extension by bending this bar in either direction in a homebuilt four-point bending rig. The average surface strain was measured with high accuracy by a resistive strain gage applied on top of the film. The near infrared imaging and spectroscopy were performed on the inverted microscope equipped with high numerical aperture reflective objective lens and InGaAs CCD cameras. PL was excited with a diode laser at either 658, 730 or 785 nm, linearly polarized in the direction of the strain. We were able to measure (n,m) types and orientation of individual nanotubes with respect to strain direction and strain dependence of their PL maxima. It was found that PL peak shifts with respect to the values measured in SDS micelles are a sum of three components. First, a small environmental shift due to difference in the dielectric constant of the surrounding media, that is constant and independent of the nanotube type. Second, shift due to isotropic compression of the film during drying. Third, shifts produced by the uniaxial loading of the film in the experiment. Second and third shifts follow expression based on the first-order expansion of the TB hamiltonian. Their magnitude is proportional to the nanotube chiral angle and strain, and direction is determined by the nanotube quantum number. PL strain dependence measured for a number of various nanotube types allows to estimate TB carbon-carbon transfer integral.

  10. A Practical Data Recovery Technique for Long-Term Strain Monitoring of Mega Columns during Construction

    PubMed Central

    Choi, Se Woon; Kwon, EunMi; Kim, Yousok; Hong, Kappyo; Park, Hyo Seon

    2013-01-01

    A practical data recovery method is proposed for the strain data lost during the safety monitoring of mega columns. The analytical relations among the measured strains are derived to recover the data lost due to unexpected errors in long-term measurement during construction. The proposed technique is applied to recovery of axial strain data of a mega column in an irregular building structure during construction. The axial strain monitoring using the wireless strain sensing system was carried out for one year and five months between 23 July 2010 and 22 February 2012. During the long-term strain sensing, three different types of measurement errors occurred. Using the recovery technique, the strain data that could not be measured at different intervals in the measurement were successfully recovered. It is confirmed that the problems that may occur during long-term wireless strain sensing of mega columns during construction could be resolved through the proposed recovery method. PMID:23966189

  11. Experimental study on strain distribution of ionic polymer-metal composite actuator using digital image correlation

    NASA Astrophysics Data System (ADS)

    Liu, Hongguang; Xiong, Ke; Wang, Man; Bian, Kan; Zhu, Kongjun

    2017-02-01

    Ionic polymer-metal composite (IPMC) cantilever actuators demonstrate significant bending deformation upon application of excitation voltage across the electrodes. In this paper a cantilever beam shaped IPMC actuator with platinum (Pt) electrodes is fabricated to investigate the micro-scale lateral deformation behavior under DC voltages using a digital microscope to measure the deformation. The digital image correlation (DIC) method is utilized to analyze the displacement and strain fields of the sample. The experimental results indicate that the longitudinal normal strain is linearly distributed along the thickness direction and the strain gradient is approximately exponential with excitation voltage. The amplitude of the transverse strain is bigger than the longitudinal strain, and the strains are also found to decrease along the length direction of the IPMC cantilever actuator. The longitudinal and transverse normal strains of the IPMC actuator under DC voltages are compressive strains due to water loss effect in the air.

  12. Strain relaxation in nanopatterned strained silicon round pillars

    NASA Astrophysics Data System (ADS)

    Himcinschi, C.; Singh, R.; Radu, I.; Milenin, A. P.; Erfurth, W.; Reiche, M.; Gösele, U.; Christiansen, S. H.; Muster, F.; Petzold, M.

    2007-01-01

    Periodic arrays of strained Si (sSi) round nanopillars were fabricated on sSi layers deposited on SiGe virtual substrates by electron-beam lithography and subsequent reactive-ion etching. The strain in the patterned sSi nanopillars was determined using high-resolution UV micro-Raman spectroscopy. The strain relaxes significantly upon nanostructuring: from 0.9% in the unpatterned sSi layer to values between 0.22% and 0.57% in the round sSi pillars with diameters from 100 up to 500nm. The strain distribution in the sSi nanopillars was analyzed by finite element (FE) modeling. The FE calculations confirm the strain relaxation after patterning, in agreement with the results obtained from Raman spectroscopy.

  13. Adaptor for Measuring Principal Strains with Tuckerman Strain Gage

    NASA Technical Reports Server (NTRS)

    Mcpherson, A E

    1943-01-01

    An adapter is described which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.

  14. The effects of academic and interpersonal stress on dating violence among college students: a test of classical strain theory.

    PubMed

    Mason, Brandon; Smithey, Martha

    2012-03-01

    This study examines Merton's Classical Strain Theory (1938) as a causative factor in intimate partner violence among college students. We theorize that college students experience general life strain and cumulative strain as they pursue the goal of a college degree. We test this strain on the likelihood of using intimate partner violence. Strain due to unrealistic expectations of intimate partnership and economic strain are also examined. The analysis examines the following causative factors representing strain: 1) the College Undergraduate Stress Scale (Renner & Mackin, 1998); 2) cumulative academic strain measured by college classification; 3) cumulative intimate partner strain measured as the length of time in the relationship; 4) academic strain measured by number of hours studied weekly, and 5) economic strain measured by number of hours worked weekly. Additionally, we examine the extent to which gender and race/ethnicity differentially affect intimate partner in the context of these measures of strain. The Conflict Tactics Scales II (Straus et al, 1996) are used to measure dating violence and include indicators for sexual coercion, physical aggression, injury, and psychological aggression. Data were collected from 142 students in lower-division classes from Texas Tech University. Results show that general strain and cumulative intimate partner strain increase the use of dating violence among college students. The longer dating partners are in a relationship, the higher the chances of psychological aggression, physical assault, and sexual coercion. Converse to our expectations, time spent working reduces psychological aggression due to reducing time spent together rather than reflecting economic strain.

  15. Highly Stretchable Strain Sensors Using an Electrospun Polyurethane Nanofiber/Graphene Composite.

    PubMed

    Hu, Daqing; Wang, Qinghe; Yu, Jixian; Hao, Wentao; Lu, Hongbo; Zhang, Guobing; Wang, Xianghua; Qiu, Longzhen

    2016-06-01

    A highly flexible and stretchable strain sensor has been prepared by coating chemical reduction of graphene oxide on electrospun polyurethane nanofiber mats. The sensor exhibits an ohmic behavior regardless of applied strains and the current monotonically increases with the increase of the tensile strain. The morphology and stability of electrospun polyurethane nanocomposite mats were also studied. The flexible and stretchable strain sensor has great potential for practical application such as efficient human-motion detection. This cheap and simple process of graphene layer provides an effective fabrication for graphene stretchable electronic devices and strain sensors due to excellent stability and electrical proper.

  16. Measured strain in Nb3Sn coils during excitation and quence

    SciTech Connect

    Caspi, S.; Barlett, S.E.; Dietderich, D. R.; Ferracin, P.; Gourlay, S. A.; Hannaford, C. R.; Hafalia, A.R.; Lietzke, A.F.; Mattafirri, S.; Nyman, M.; Sabbi, G.

    2005-06-01

    The strain in a high field Nb{sub 3}Sn coil was measured during magnet assembly, cool-down, excitation and spot heater quenches. Strain was measured with a full bridge strain gauge mounted directly over the turns and impregnated with the coil. Two such coils were placed in a 'common coil' fashion capable of reaching 11 T at 4.2 K. The measured steady state strain in the coil is compared with results obtained using the FEM code ANSYS. During quenches, the transient strain (due to temperature rise) was also measured and compared with the calculated mechanical time response to a quench.

  17. Measured Strain of Nb3Sn Coils During Excitation and Quench

    SciTech Connect

    Caspi, S.; Bartlett, S.E.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hannaford, C.R.; Hafalia, A.R.; Lietzke, S.; Mattafirri,M.; Nyman, M.; Sabbi, G.

    2005-04-16

    The strain in a high field Nb{sub 3}Sn coil was measured during magnet assembly, cool-down, excitation and spot heater quenches. Strain was measured with a full bridge strain gauge mounted directly over the turns and impregnated with the coil. Two such coils were placed in a ''common coil'' fashion capable of reaching 11T at 4.2K. The measured steady state strain in the coil is compared with results obtained using the FEM code ANSYS. During quenches, the transient strain (due to temperature rise) was also measured and compared with the calculated mechanical time response to a quench.

  18. Biomechanical strain of goldsmiths.

    PubMed

    Cândido, Paula Emanuela Fernandes; Teixeira, Juliana Vieira Schmidt; Moro, Antônio Renato Pereira; Gontijo, Leila Amaral

    2012-01-01

    The work of the goldsmiths consists in the manufacture of jewelry. The piece, be it an earring, bracelet or necklace, is hand-assembled. This task requires precision, skill, kindness and patience. In this work, we make use of tools such as cuticle clippers and rounded tip, beads or precious stones and also pieces of metal. This type of activity requires a biomechanical stress of hands and wrists. In order to quantify the biomechanical stress, we performed a case study to measure the movements performed by an assembly of pieces of jewelry. As method for research, filming was done during assembly of parts to a paste, using a Nikon digital camera, for 1 (one) hour. The film was edited by Kinovea software, and the task was divided into cycles, each cycle corresponds to a complete object. In one cycle, there are four two movements of supination and pronation movements of the forearm. The cycle lasts approximately sixteen seconds, totaling 1800 cycles in eight hours. Despite the effort required of the wrists, the activity shows no complaints from the employees, but this fact does not mischaracterizes the ability of employees to acquire repetitive strain injuries and work-related musculoskeletal disorders.

  19. Characterization of Salmonella enteritidis strains.

    PubMed Central

    Poppe, C; McFadden, K A; Brouwer, A M; Demczuk, W

    1993-01-01

    A study was conducted to characterize 318 Salmonella enteritidis strains that were mainly isolated from poultry and their environment in Canada. Biotype, phagetype (PT), plasmid profile (PP), hybridization with a plasmid-derived virulence sequence probe, antibiotic resistance, outer membrane proteins (OMPs), and lipopolysaccharide (LPS) profiles were determined. Relationships of these properties to one another, and their diagnostic and pathogenic significance were assessed. Biotyping indicated that failure to ferment rhamnose was sometimes useful as a marker for epidemiologically related strains. Phagetyping was the most effective method for subdividing S. enteritidis; it distinguished 12 PTs. Phagetype 13 was occasionally associated with septicemia and mortality in chickens. The strains belonged to 15 PPs. A 36 megadalton (MDa) plasmid was found in 97% of the strains. Only the 36 MDa plasmid hybridized with the probe. Seventeen percent of the strains were drug resistant; all strains were sensitive to ciprofloxacin. Thirty-five of 36 strains possessed the same OMP profile, and 36 of 41 strains contained smooth LPS. Images Fig. 1. PMID:8358678

  20. Difference Between Strain and Sprain.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    Provided in this description of the differences between a strain (damage to the muscle or tendon) and a sprain (damage to the ligament) are definitions of mild, moderate, and severe (first, second, and third degree) strains and sprains. A final caution is given that these are two separate and distinct problems and should be treated as such. (DC)

  1. Hypothetical strain-free oligoradicals

    PubMed Central

    Hoffmann, Roald; Eisenstein, Odile; Balaban, Alexandru T.

    1980-01-01

    Several new classes of oligoradicals free of angle strain are suggested and examined by means of molecular orbital calculations. The collapse products of these hypothetical radicals are highly strained molecules. Various electronic strategies for the stabilization of these oligoradicals have been explored. PMID:16592882

  2. Occurrence of Urease in T Strains of Mycoplasma

    PubMed Central

    Shepard, Maurice C.; Lunceford, Carl D.

    1967-01-01

    A previously unknown metabolite necessary for growth of T strains of Mycoplasma in artificial culture media has been identified as urea. The source of this metabolite was the mammalian plasma or serum enrichment of the culture medium. Normal horse serum was the most satisfactory native protein enrichment for cultivation of T strains of mycoplasma, and it is believed that its superior performance in agar and fluid culture media is associated with its relatively high urea content (approximately 40 mg/100 ml). T-strain urease activity was maximal at pH 6.0 ± 0.5. This is also the optimal pH for growth of T strains. Substrate concentrations greater than 1.0% urea were inhibitory to growth and urease activity of T-strain organisms, and optimal urea concentrations in fluid media appeared to lie within the range of 0.008 to 0.01 m. This range of urea concentration permitted maximal growth of T-strain organisms without rapid loss of viability due to excessive ammonia accumulation and rise in pH to lethal levels. T strains of Mycoplasma were cultivated in a serum-free fluid medium containing urea as the only added metabolite and nitrogen source. T strains are the only known human mycoplasmas which exhibit urease activity, and this biochemical marker can be employed as an aid in the detection and identification of T strains of Mycoplasma (urease color test) and in distinguishing T strains from other members of the human Mycoplasma group. PMID:6025439

  3. Building up strain in colloidal metal nanoparticle catalysts

    NASA Astrophysics Data System (ADS)

    Sneed, Brian T.; Young, Allison P.; Tsung, Chia-Kuang

    2015-07-01

    The focus on surface lattice strain in nanostructures as a fundamental research topic has gained momentum in recent years as scientists investigated its significant impact on the surface electronic structure and catalytic properties of nanomaterials. Researchers have begun to tell a more complete story of catalysis from a perspective which brings this concept to the forefront of the discussion. The nano-`realm' makes the effects of surface lattice strain, which acts on the same spatial scales, more pronounced due to a higher ratio of surface to bulk atoms. This is especially evident in the field of metal nanoparticle catalysis, where displacement of atoms on surfaces can significantly alter the sorption properties of molecules. In part, the concept of strain-engineering for catalysis opened up due to the achievements that were made in the synthesis of a more sophisticated nanoparticle library from an ever-expanding set of methodologies. Developing synthesis methods for metal nanoparticles with well-defined and strained architectures is a worthy goal that, if reached, will have considerable impact in the search for catalysts. In this review, we summarize the recent accomplishments in the area of surface lattice-strained metal nanoparticle synthesis, framing the discussion from the important perspective of surface lattice strain effects in catalysis.

  4. Strain gage system evaluation program

    NASA Technical Reports Server (NTRS)

    Dolleris, G. W.; Mazur, H. J.; Kokoszka, E., Jr.

    1978-01-01

    A program was conducted to determine the reliability of various strain gage systems when applied to rotating compressor blades in an aircraft gas turbine engine. A survey of current technology strain gage systems was conducted to provide a basis for selecting candidate systems for evaluation. Testing and evaluation was conducted in an F 100 engine. Sixty strain gage systems of seven different designs were installed on the first and third stages of an F 100 engine fan. Nineteen strain gage failures occurred during 62 hours of engine operation, for a survival rate of 68 percent. Of the failures, 16 occurred at blade-to-disk leadwire jumps (84 percent), two at a leadwire splice (11 percent), and one at a gage splice (5 percent). Effects of erosion, temperature, G-loading, and stress levels are discussed. Results of a post-test analysis of the individual components of each strain gage system are presented.

  5. Effect of coating on the strain transfer of optical fiber sensors.

    PubMed

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2011-01-01

    Optical fiber strain sensors with light weight, small dimensions and immunity to electromagnetic interference are widely used in structural health monitoring devices. As a sensor, it is expected that the strains between the optical fiber and host structure are the same. However, due to the shear deformation of the protective coating, the optical fiber strain is different from that of host structure. To improve the measurement accuracy, the strain measured by the optical fiber needs to be modified to reflect the influence of the coating. In this investigation, a theoretical model of the strain transferred from the host material to the optical fiber is developed to evaluate the interaction between the host material and coating. The theoretical predictions are validated with a numerical analysis using the finite element method. Experimental tests are performed to reveal the differential strains between the optical fiber strain sensor and test specimen. The Mach-Zehnder interferometric type fiber-optic sensor is adopted to measure the strain. Experimental results show that the strain measured at the optical fiber is lower than the true strain in the test specimen. The percentage of strain in the test specimen actually transferred to the optical fiber is dependent on the bonded length of the optical fiber and the protective coating. The general trend of the strain transformation obtained from both experimental tests and theoretical predictions shows that the longer the bonded length and the stiffer the coating the more strain is transferred to the optical fiber.

  6. Strain Insensitive Optical Phase Locked Loop

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O. (Inventor); Rogowski, Robert S. (Inventor)

    1998-01-01

    A strain sensor uses optical fibers including strain insensitive portions and a strain sensitive portion. The optical fibers form a sensitive arm of an optical phase locked loop (OPLL). The use of the OPLL allows for multimode optical fiber to be used in a strain insensitive configuration. Only strain information for the strain sensitive portion is monitored rather than the integrated strain measurements commonly made with optical fiber sensors.

  7. Management of severe pain due to lumbar disk protrusion.

    PubMed

    Conroy, Liam

    2015-03-01

    Lumbar intervertebral disk protrusion can cause excruciating pain in severe cases, which can be exacerbated by activity such as sitting down and straining at stool. Acute sciatica due to disk rupture will improve within 1 to 3 months. The efficacy of drugs used for the management of sciatica in primary care is unclear. Severe cases can require opioid analgesia, however people taking opioids for pain relief frequently present with opioid-induced bowel dysfunction. The use of transforaminal steroid injections is a controversial issue and repeat steroid injections should be considered in light of the risk-benefit profile of the individual patient.

  8. High Strain Rate Behavior of Polyurea Compositions

    NASA Astrophysics Data System (ADS)

    Joshi, Vasant; Milby, Christopher

    2011-06-01

    Polyurea has been gaining importance in recent years due to its impact resistance properties. The actual compositions of this viscoelastic material must be tailored for specific use. It is therefore imperative to study the effect of variations in composition on the properties of the material. High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with titanium bars. The polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. The materials have been tested up to strain rates of 6000/s. Results from these tests have shown interesting trends on the high rate behavior. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Refinement in experimental methods and comparison of results using aluminum Split Hopkinson Bar is presented.

  9. Spherical nanoindentation stress–strain curves

    SciTech Connect

    Pathak, Siddhartha; Kalidindi, Surya R.

    2015-03-24

    Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elastic–plastic response of materials under contact loading has only been realized in the past few years – mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stress–strain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stress–strain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength in the sample, as well as certain aspects of their post-yield behavior, and have been critically validated through numerical simulations using finite element models as well as direct in situ scanning electron microscopy (SEM) measurements on micro-pillars. Much of this recent progress was made possible through the introduction of a new measure of indentation strain and the development of new protocols to locate the effective zero-point of initial contact between the indenter and the sample in the measured datasets. As a result, this has led to an important key advance in this field where it is now possible to reliably identify and analyze the initial loading segment in the indentation experiments.

  10. Ultrasound strain imaging using Barker code

    NASA Astrophysics Data System (ADS)

    Peng, Hui; Tie, Juhong; Guo, Dequan

    2017-01-01

    Ultrasound strain imaging is showing promise as a new way of imaging soft tissue elasticity in order to help clinicians detect lesions or cancers in tissues. In this paper, Barker code is applied to strain imaging to improve its quality. Barker code as a coded excitation signal can be used to improve the echo signal-to-noise ratio (eSNR) in ultrasound imaging system. For the Baker code of length 13, the sidelobe level of the matched filter output is -22dB, which is unacceptable for ultrasound strain imaging, because high sidelobe level will cause high decorrelation noise. Instead of using the conventional matched filter, we use the Wiener filter to decode the Barker-coded echo signal to suppress the range sidelobes. We also compare the performance of Barker code and the conventional short pulse in simulation method. The simulation results demonstrate that the performance of the Wiener filter is much better than the matched filter, and Baker code achieves higher elastographic signal-to-noise ratio (SNRe) than the short pulse in low eSNR or great depth conditions due to the increased eSNR with it.

  11. Spherical nanoindentation stress–strain curves

    DOE PAGES

    Pathak, Siddhartha; Kalidindi, Surya R.

    2015-03-24

    Although indentation experiments have long been used to measure the hardness and Young's modulus, the utility of this technique in analyzing the complete elastic–plastic response of materials under contact loading has only been realized in the past few years – mostly due to recent advances in testing equipment and analysis protocols. This paper provides a timely review of the recent progress made in this respect in extracting meaningful indentation stress–strain curves from the raw datasets measured in instrumented spherical nanoindentation experiments. These indentation stress–strain curves have produced highly reliable estimates of the indentation modulus and the indentation yield strength inmore » the sample, as well as certain aspects of their post-yield behavior, and have been critically validated through numerical simulations using finite element models as well as direct in situ scanning electron microscopy (SEM) measurements on micro-pillars. Much of this recent progress was made possible through the introduction of a new measure of indentation strain and the development of new protocols to locate the effective zero-point of initial contact between the indenter and the sample in the measured datasets. As a result, this has led to an important key advance in this field where it is now possible to reliably identify and analyze the initial loading segment in the indentation experiments.« less

  12. High temperature strain measurement with a resistance strain gage

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Fichtel, ED; Mcdaniel, Amos

    1993-01-01

    A PdCr based electrical resistance strain gage was demonstrated in the laboratory to be a viable sensor candidate for static strain measurement at high temperatures. However, difficulties were encountered while transferring the sensor to field applications. This paper is therefore prepared for recognition and resolution of the problems likely to be encountered with PdCr strain gages in field applications. Errors caused by the measurement system, installation technique and lead wire attachment are discussed. The limitations and some considerations related to the temperature compensation technique used for this gage are also addressed.

  13. Recent advances in echocardiography: strain and strain rate imaging

    PubMed Central

    Mirea, Oana; Duchenne, Jurgen; Voigt, Jens-Uwe

    2016-01-01

    Deformation imaging by echocardiography is a well-established research tool which has been gaining interest from clinical cardiologists since the introduction of speckle tracking. Post-processing of echo images to analyze deformation has become readily available at the fingertips of the user. New parameters such as global longitudinal strain have been shown to provide added diagnostic value, and ongoing efforts of the imaging societies and industry aimed at harmonizing methods will improve the technique further. This review focuses on recent advances in the field of echocardiographic strain and strain rate imaging, and provides an overview on its current and potential future clinical applications. PMID:27158476

  14. Inelastic Strain Analysis of Solder Joint in NASA Fatigue Specimen

    NASA Technical Reports Server (NTRS)

    Dasgupta, Abhijit; Oyan, Chen

    1991-01-01

    The solder fatigue specimen designed by NASA-GSFC/UNISYS is analyzed in order to obtain the inelastic strain history during two different representative temperature cycles specified by UNISYS. In previous reports (dated July 25, 1990, and November 15, 1990), results were presented of the elastic-plastic and creep analysis for delta T = 31 C cycle, respectively. Subsequent results obtained during the current phase, from viscoplastic finite element analysis of the solder fatigue specimen for delta T = 113 C cycle are summarized. Some common information is repeated for self-completeness. Large-deformation continuum formulations in conjunction with a standard linear solid model is utilized for modeling the solder constitutive creep-plasticity behavior. Relevant material properties are obtained from the literature. Strain amplitudes, mean strains, and residual strains (as well as stresses) accumulated due to a representative complete temperature cycle are obtained as a result of this analysis. The partitioning between elastic strains, time-independent inelastic (plastic) strains, and time-dependent inelastic (creep) strains is also explicitly obtained for two representative cycles. Detailed plots are presented for two representative temperature cycles. This information forms an important input for fatigue damage models, when predicting the fatigue life of solder joints under thermal cycling

  15. High-sensitivity strain visualization using electroluminescence technologies

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Jo, Hongki

    2016-04-01

    Visualizing mechanical strain/stress changes is an emerging area in structural health monitoring. Several ways are available for strain change visualization through the color/brightness change of the materials subjected to the mechanical stresses, for example, using mechanoluminescence (ML) materials and mechanoresponsive polymers (MRP). However, these approaches were not effectively applicable for civil engineering system yet, due to insufficient sensitivity to low-level strain of typical civil structures and limitation in measuring both static and dynamic strain. In this study, design and validation for high-sensitivity strain visualization using electroluminescence technologies are presented. A high-sensitivity Wheatstone bridge, of which bridge balance is precisely controllable circuits, is used with a gain-adjustable amplifier. The monochrome electroluminescence (EL) technology is employed to convert both static and dynamic strain change into brightness/color change of the EL materials, through either brightness change mode (BCM) or color alternation mode (CAM). A prototype has been made and calibrated in lab, the linearity between strain and brightness change has been investigated.

  16. Strain rate sensitivity of nanoindentation creep in an AlCoCrFeNi high-entropy alloy

    NASA Astrophysics Data System (ADS)

    Jiao, Z. M.; Wang, Z. H.; Wu, R. F.; Qiao, J. W.

    2016-09-01

    Creep behaviors of an AlCoCrFeNi high-entropy alloy with the body-centered cubic structure were investigated by nanoindentation. The enhanced strain gradient induced by higher strain rate leads to decreased strain rate sensitivity during creep process. The present alloy exhibits excellent creep resistance, mainly due to its large entropy of mixing and highly distorted lattice structure.

  17. Reversible Modulation of Spontaneous Emission by Strain in Silicon Nanowires

    PubMed Central

    Shiri, Daryoush; Verma, Amit; Selvakumar, C. R.; Anantram, M. P.

    2012-01-01

    We computationally study the effect of uniaxial strain in modulating the spontaneous emission of photons in silicon nanowires. Our main finding is that a one to two orders of magnitude change in spontaneous emission time occurs due to two distinct mechanisms: (A) Change in wave function symmetry, where within the direct bandgap regime, strain changes the symmetry of wave functions, which in turn leads to a large change of optical dipole matrix element. (B) Direct to indirect bandgap transition which makes the spontaneous photon emission to be of a slow second order process mediated by phonons. This feature uniquely occurs in silicon nanowires while in bulk silicon there is no change of optical properties under any reasonable amount of strain. These results promise new applications of silicon nanowires as optoelectronic devices including a mechanism for lasing. Our results are verifiable using existing experimental techniques of applying strain to nanowires. PMID:22708056

  18. Laser-based strain measurements for high temperature applications

    NASA Technical Reports Server (NTRS)

    Lant, Christian T.

    1992-01-01

    The Instrumentation and Control Technology Division at NASA Lewis Research Center has developed a high performance optical strain measurement system for high temperature applications using wires and fibers. The system is based on Yamaguchi's two-beam speckle-shift strain measurement technique. The system automatically calculates surface strains at a rate of 5 Hz using a digital signal processor in a high speed micro-computer. The system is fully automated, and can be operated remotely. This report describes the speckle-shift technique and the latest NASA system design. It also shows low temperature strain test results obtained from small diameter tungsten, silicon carbide, and sapphire specimens. These specimens are of interest due to their roles in composite materials research at NASA Lewis.

  19. Effect of asymmetric strain relaxation on dislocation relaxation processes in heteroepitaxial semiconductors

    NASA Astrophysics Data System (ADS)

    Andersen, D.; Hull, R.

    2017-02-01

    The effect of asymmetric interfacial strain configurations upon the generation of misfit dislocation arrays in lattice mismatched epitaxy is considered. For example, elastic strain relaxation for Si1-xGex/Si(110) films is uniaxial, assuming glide on {111} planes as expected for the diamond cubic system, which leads to asymmetric strain relief. Here, we extend our previously developed relaxation model for generation of dislocation arrays in SiGe/Si, by accounting for how the different energetics of asymmetrically strained films affect the kinetics of the relaxation process. Similarly, non-polar III-nitride epitaxial films have asymmetric strain from the outset of growth due to the different c/a lattice parameter ratios. In both systems, the asymmetric strain is represented by an additional term in the misfit dislocation applied stress equation. In SiGe/Si(110), a simple elasticity analysis of the strain produced by the uniaxial array of dislocations predicts that the relaxation orthogonal to the dislocation line direction occurs at a faster rate than predicted by purely biaxial strain relief due to the contributions of the strain parallel to the dislocations. This difference is because the strain parallel to the dislocation line directions continues to resolve stress onto the misfit dislocations even as the orthogonal strain is minimized. As a result, the minimum strain energy is predicted to occur for a dislocation spacing, which produces tensile layer strain in the orthogonal direction. Such tensile strain may modify the (opto)electronic properties of a Si, Ge, or GeSi epilayer but is only predicted to occur for advanced stages of relaxation. These asymmetric derivations are applicable to any thin film system where strain is not strictly biaxial.

  20. Low TCR nanocomposite strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); Chen, Ximing (Inventor)

    2012-01-01

    A high temperature thin film strain gage sensor capable of functioning at temperatures above 1400.degree. C. The sensor contains a substrate, a nanocomposite film comprised of an indium tin oxide alloy, zinc oxide doped with alumina or other oxide semiconductor and a refractory metal selected from the group consisting of Pt, Pd, Rh, Ni, W, Ir, NiCrAlY and NiCoCrAlY deposited onto the substrate to form an active strain element. The strain element being responsive to an applied force.

  1. Virtual strain gage size study

    SciTech Connect

    Reu, Phillip L.

    2015-09-22

    DIC is a non-linear low-pass spatial filtering operation; whether we consider the effect of the subset and shape function, the strain window used in the strain calculation, of other post-processing of the results, each decision will impact the spatial resolution, of the measurement. More fundamentally, the speckle size limits, the spatial resolution by dictating the smallest possible subset. After this decision the processing settings are controlled by the allowable noise level balanced by possible bias errors created by the data filtering. This article describes a process to determine optimum DIC software settings to determine if the peak displacements or strains are being found.

  2. Radio Frequency (RF) strain monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor); Rogowski, Robert S. (Inventor); Holben, Milford S., Jr. (Inventor)

    1988-01-01

    This invention relates to an apparatus for measuring strain in a structure. In particular, the invention detects strain in parts per million to over ten percent along an entire length (or other dimension) of a structure measuring a few millimeters to several kilometers. By using a propagation path bonded to the structure, the invention is not limited by the signal attenuation characteristics of the structure and thus frequencies in the megahertz to gigahertz range may be used to detect strain in part per million to over ten percent with high precision.

  3. Strain accumulation in quasicrystalline solids

    NASA Technical Reports Server (NTRS)

    Nori, Franco; Ronchetti, Marco; Elser, Veit

    1988-01-01

    The relaxation of two-dimensional quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously is studied. Whereas ideal, quasi-periodic networks are stable against such perturbations, significant accumulations of strain in a class of disordered networks generated by a growth process are found. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation observed in these networks also grows linearly with system size. Finally, dependence of strain accumulation on cooling rate is found.

  4. Plasmid-mediate transfer of FLO1 into industrial Saccharomyces cerevisiae PE-2 strain creates a strain useful for repeat-batch fermentations involving flocculation-sedimentation.

    PubMed

    Gomes, Daniel G; Guimarães, Pedro M R; Pereira, Francisco B; Teixeira, José A; Domingues, Lucília

    2012-03-01

    The flocculation gene FLO1 was transferred into the robust industrial strain Saccharomyces cerevisiae PE-2 by the lithium acetate method. The recombinant strain showed a fermentation performance similar to that of the parental strain. In 10 repeat-batch cultivations in VHG medium with 345 g glucose/L and cell recycling by flocculation-sedimentation, an average final ethanol concentration of 142 g/L and an ethanol productivity of 2.86 g/L/h were achieved. Due to the flocculent nature of the recombinant strain it is possible to reduce the ethanol production cost because of lower centrifugation and distillation costs.

  5. Genotype characterization of commonly used Newcastle disease virus vaccine strains of India.

    PubMed

    Dey, Sohini; Chellappa, Madhan Mohan; Gaikwad, Satish; Kataria, Jag Mohan; Vakharia, Vikram N

    2014-01-01

    Newcastle disease is an avian pathogen causing severe economic losses to the Indian poultry industry due to recurring outbreaks in vaccinated and unvaccinated flocks. India being an endemic country, advocates vaccination against the virus using lentogenic and mesogenic strains. Two virus strains which are commonly used for vaccination are strain F (a lentogenic virus) and strain R2B (a mesogenic virus). Strain F is given to 0-7 days old chicks and R2B is given to older birds which are around 6-8 weeks old. To understand the genetic makeup of these two strains, a complete genome study and phylogenetic analysis of the F, HN genes of these vaccine strains were carried out. Both the viral strains had a genome length of 15,186 nucleotides and consisted of six genes with conserved complimentary 3' leader and 5' trailer regions. The fusion protein cleavage site of strain F is GGRQGRL and strain R2B is RRQKRF. Although both the viral strains had different virulence attributes, the length of the HN protein was similar with 577 amino acids. Phylogenetic analysis of F, HN and complete genome sequences grouped these two strains in genotype II category which are considered as early genotypes and corroborated with their years of isolation.

  6. Mechanical and electronic properties of monolayer and bilayer phosphorene under uniaxial and isotropic strains

    NASA Astrophysics Data System (ADS)

    Hu, Ting; Han, Yang; Dong, Jinming

    2014-11-01

    The mechanical and electronic properties of both the monolayer and bilayer phosphorenes under either isotropic or uniaxial strain have been systematically investigated using first-principles calculations. It is interesting to find that: 1) Under a large enough isotropic tensile strain, the monolayer phosphorene would lose its pucker structure and transform into a flat hexagonal plane, while two inner sublayers of the bilayer phosphorene could be bonded due to its interlayer distance contraction. 2) Under the uniaxial tensile strain along a zigzag direction, the pucker distance of each layer in the bilayer phosphorene can exhibit a specific negative Poisson’s ratio. 3) The electronic properties of both the monolayer and bilayer phosphorenes are sensitive to the magnitude and direction of the applied strains. Their band gaps decrease more rapidly under isotropic compressive strain than under uniaxial strain. Also, their direct-indirect band gap transitions happen at the larger isotropic tensile strains compared with that under uniaxial strain. 4) Under the isotropic compressive strain, the bilayer phosphorene exhibits a transition from a direct-gap semiconductor to a metal. In contrast, the monolayer phosphorene initially has the direct-indirect transition and then transitions to a metal. However, under isotropic tensile strain, both the bilayer and monolayer phosphorene show the direct-indirect transition and, finally, the transition to a metal. Our numerical results may open new potential applications of phosphorene in nanoelectronics and nanomechanical devices by external isotropic strain or uniaxial strain along different directions.

  7. PLASTICITY AND NON-LINEAR ELASTIC STRAINS

    DTIC Science & Technology

    conditions existing in plane waves in an extended medium to give the time rate of change of stress as a function of the time rate of change of strain, the stress invariants, the total strain and the plastic strain. (Author)

  8. Variation in genotype and higher virulence of a strain of Sporothrix schenckii causing disseminated cutaneous sporotrichosis.

    PubMed

    Zhang, Zhenying; Liu, Xiaoming; Lv, Xuelian; Lin, Jingrong

    2011-12-01

    Sporotrichosis is usually a localized, lymphocutaneous disease, but its disseminated type was rarely reported. The main objective of this study was to identify specific DNA sequence variation and virulence of a strain of Sporothrix schenckii isolated from the lesion of disseminated cutaneous sporotrichosis. We confirmed this strain to be S. schenckii by(®) tubulin and chitin synthase gene sequence analysis in addition to the routine mycological and partial ITS and NTS sequencing. We found a 10-bp deletion in the ribosomal NTS region of this strain, in reference to the sequence of control strains isolated from fixed cutaneous sporotrichosis. After inoculated into immunosuppressed mice, this strain caused more extensive system involvement and showed stronger virulence than the control strain isolated from a fixed cutaneous sporotrichosis. Our study thus suggests that different clinical manifestation of sporotrichosis may be associated with variation in genotype and virulence of the strain, independent of effects due to the immune status of the host.

  9. Stress Corrosion Cracking Behavior of Interstitial Free Steel Via Slow Strain Rate Technique

    NASA Astrophysics Data System (ADS)

    Murkute, Pratik; Ramkumar, J.; Mondal, K.

    2016-07-01

    An interstitial free steel is subjected to slow strain rate tests to investigate the stress corrosion cracking (SCC) behavior at strain rates ranging from 10-4 to 10-6s-1 in air and 3.5 wt.% NaCl solution. The ratios of time to failure, failure strain, and ultimate tensile stress at different strain rates in air to that in corrosive were considered as SCC susceptibility. Serrated stress-strain curve observed at lowest strain rate is explained by the Portevin-Le Chatelier effect. Maximum susceptibility to SCC at lowest strain rate is attributed to the soluble γ-FeOOH in the rust analyzed by Fourier Transformed Infrared spectroscopy. Mechanism for SCC relates to the anodic dissolution forming the groove, where hydrogen embrittlement can set in and finally fracture happens due to triaxiality.

  10. Effect of thermally induced strain on optical fiber sensors embedded in cement-based composites

    NASA Astrophysics Data System (ADS)

    Yuan, Li-bo; Zhou, Li-min; Jin, Wei; Lau, K. T.; Poon, Chi-kin

    2003-04-01

    A critical issue in developing a fiber-optic strain gauge is its codependency on temperature and strain. Any changes in the output of the optical fiber sensor due to its own thermal sensitivity and the thermal expansion of the most material will be misinterpreted as a change in shape-induced strain in the structure. This codependence is often referred to as thermally induced apparent strain or simply apparent strain. In this paper, an analytical model was developed to evaluate the thermally induced strain in fiber optic sensors embedded in cement-based composites. The effects of thermal induced strain on embedded optical fiber were measured with a white-light fiber-optic Michelson sensing interferometer for a number of cement-based host materials.

  11. Carbon fiber-ZnO nanowire hybrid structures for flexible and adaptable strain sensors.

    PubMed

    Liao, Qingliang; Mohr, Markus; Zhang, Xiaohui; Zhang, Zheng; Zhang, Yue; Fecht, Hans-Jörg

    2013-12-21

    We report the flexible piezotronic strain sensors fabricated using carbon fiber-ZnO nanowire hybrid structures by a novel and reliable method. The I-V characteristic of the sensor shows high sensitivity to external strain due to the change in Schottky barrier height (SBH), which has a linear relationship with strain. This fabricated strain sensor has a quick, real-time current response under both static and dynamic mechanical loads. The change in SBH resulted from the strain-induced piezoelectric potential is investigated by band gap theory. In this work we develop a new feasible method to fabricate a flexible strain sensor within the fabric adapted to textile structures, able to measure their strain.

  12. Magnetic Domain Strain Sensor Program

    DTIC Science & Technology

    1990-08-01

    static strain measurement at elevated temperatures. 2.2 Magnetic Strain Measurement Theory The initial work at GED investigated the Barkhausen effect...including large and small Barkhausen jumps. This is a wave propaga- tion phenomenon in which a magnetic wave velocity is measured. The wave velocity in a...theory explaining the phenomenon that deviates from the Barkhausen effect. Some basic concepts had to be examined to better understand magnetic phenomena

  13. HIGH-TEMPERATURE STRAIN GAGE,

    DTIC Science & Technology

    The patent involves a high-temperature tensometer consisting of a strain-sensitive wire grid, a connecting and insulating material, a sub-layer of...heat-resistant material, deposited on the part being investigated or on a backing by gas flame deposition, and a connector to fasten the strain...adhesion, the tension-sensitive wire grid is fastened through the sub-layer to the part being tested by the connecting and insulating material. (Author)

  14. NUTRITION OF FIVE BACTEROIDES STRAINS

    PubMed Central

    Quinto, Grace

    1962-01-01

    Quinto, Grace (University of Kentucky College of Medicine, Lexington). Nutrition of five Bacteroides strains. J. Bacteriol. 84:559–562. 1962.—Some of the nutritional requirements of five gram-negative anaerobic bacilli, including Ristella perfoetens, Zuberella clostridiformis, and three Bacteroides strains freshly isolated from clinical exudates, were investigated. A fluid maintenance medium was developed in which the three freshly isolated strains, C-4, C-7, and C-2795, grew maximally in 12 to 24 hr. The maintenance medium contained 2.0% Trypticase and Proteose Peptone, 0.5% glucose, and 0.1% sodium thioglycolate; it was adjusted to pH 7.2 and supplemented with 0.1 μg of hemin/ml. Strains C-4, C-7, and C-2795 were cultivated through 14 serial cultures in fluid maintenance medium containing 0.1 μg of hemin/ml. The most satisfactory inoculum was a 1:100 or 1:1,000 dilution of a 24-hr seed culture. All the strains except Z. clostridiformis grew serially in a defined medium. R. perfoetens required pantothenic acid, nicotinic acid, and the following amino acids: histidine, tryptophan, tyrosine, valine, phenylalanine, cystine, and probably arginine, glutamic acid, methionine, glycine, isoleucine, leucine, and lysine. The C-4, C-7, and C-2795 strains required the hemin supplement in defined medium, but not vitamins, purines, or pyrimidines. PMID:13972793

  15. Compliant intracortical implants reduce strains and strain rates in brain tissue in vivo

    NASA Astrophysics Data System (ADS)

    Sridharan, Arati; Nguyen, Jessica K.; Capadona, Jeffrey R.; Muthuswamy, Jit

    2015-06-01

    Objective. The objective of this research is to characterize the mechanical interactions of (1) soft, compliant and (2) non-compliant implants with the surrounding brain tissue in a rodent brain. Understanding such interactions will enable the engineering of novel materials that will improve stability and reliability of brain implants. Approach. Acute force measurements were made using a load cell in n = 3 live rats, each with 4 craniotomies. Using an indentation method, brain tissue was tested for changes in force using established protocols. A total of 4 non-compliant, bare silicon microshanks, 3 non-compliant polyvinyl acetate (PVAc)-coated silicon microshanks, and 6 compliant, nanocomposite microshanks were tested. Stress values were calculated by dividing the force by surface area and strain was estimated using a linear stress-strain relationship. Micromotion effects from breathing and vascular pulsatility on tissue stress were estimated from a 5 s interval of steady-state measurements. Viscoelastic properties were estimated using a second-order Prony series expansion of stress-displacement curves for each shank. Main results. The distribution of strain values imposed on brain tissue for both compliant nanocomposite microshanks and PVAc-coated, non-compliant silicon microshanks were significantly lower compared to non-compliant bare silicon shanks. Interestingly, step-indentation experiments also showed that compliant, nanocomposite materials significantly decreased stress relaxation rates in the brain tissue at the interface (p < 0.05) compared to non-compliant silicon and PVAc-coated silicon materials. Furthermore, both PVAc-coated non-compliant silicon and compliant nanocomposite shanks showed significantly reduced (by 4-5 fold) stresses due to tissue micromotion at the interface. Significance. The results of this study showed that soft, adaptive materials reduce strains and strain rates and micromotion induced stresses in the surrounding brain tissue

  16. Molecular dynamics simulation of a solid platinum nanowire under uniaxial tensile strain: Temperature and strain-rate effects

    NASA Astrophysics Data System (ADS)

    Koh, S. J. A.; Lee, H. P.; Lu, C.; Cheng, Q. H.

    2005-08-01

    Nanoscale research has been an area of active research over the past fifteen years. This is due to the overall enhanced properties of nanomaterials due to size effects, surface effects, and interface effects, which typically showed up in materials with characteristic size smaller than 100nm . This study focuses on the molecular dynamics (MD) simulation of an infinitely long, cylindrical platinum nanowire, with an approximate diameter of 1.4nm . The nanowire was subjected to uniaxial tensile strain along the [001] axis. The changes in crystal structure during deformation were analyzed and its mechanical properties were deduced from the simulation. Classical MD simulation was employed in this study, with the empirical Sutton-Chen pair functional used to describe the interatomic potential between the platinum atoms. The Berendsen loose-coupling thermostat was selected for finite-temperature control of the simulated system, with a time constant of 25% of the total relaxation time during each strain increment. The nanowire was subjected to strain rates of 0.04%, 0.4%, and 4.0%ps-1 , at simulation temperatures of 50 and 300K , in order to study the effects of different strain rates and thermal conditions on the deformation characteristics and mechanical properties of the nanowire. It was found that the stress-strain response of the nanowire showed clear periodic, stepwise dislocation-relaxation-recrystallization behavior at low temperature and strain rate, where crystal order and stability were highly preserved. The onset of amorphous crystal deformation occurred at 0.4%ps-1 , and fully amorphous deformation took place at 4.0%ps-1 , with amorphous melting detected at 300K . Due to higher entropy of the nanowire at higher temperature and strain rate, periodic stress-strain behavior became less clearly defined, and superplasticity behavior was observed. This characteristic was significantly enhanced due to the development of a single-walled helical substructure at 300K

  17. Strain-dependent permeability of volcanic rocks.

    NASA Astrophysics Data System (ADS)

    Farquharson, Jamie; Heap, Michael; Baud, Patrick

    2016-04-01

    the degree of strain to which is subjected. Volcanic processes such as dome extrusion, which involve progressive strain on complex fault systems, have been seen to cause fault sliding and the prolific generation of fault gouge. Our results indicate that the permeability of these faults will tend to remain constant or increase during continued extrusion, allowing magmatic gases to readily outgas through permeable fault architectures despite the generation and accumulation of gouge. On the other hand, deeper regions of the edifice that will typically be compacting due to the relatively higher confining pressures, will exhibit a continuous decrease in permeability. The interplay between permeability-increasing and permeability-decreasing processes within the edifice is likely to influence outgassing and eruptive cycles at active volcanoes.

  18. The variation of the yield stress of Ti alloys with strain rate at high temperatures

    SciTech Connect

    Rosen, R.S.; Paddon, S.P.; Kassner, M.E.

    1999-06-01

    This study extended investigation on the elevated-temperature yield-strength dependence of beta-phase titanium alloys on strain rate and temperature. Yield stresses were found to increase substantially with increasing strain rate at elevated temperatures due to the high strain-rate sensitivity of titanium at high temperatures. Above 1000 C, the strain-rate sensitivities were found to increase substantially with increasing temperature and/or decreasing strain rate. The six alloys examined were TIMETAL 21S, Ti-15-3-, Ti-6-4, Ti-13-11-3, Beta C, and Beta III. There was particular interest in determining the strain-rate sensitivity of these alloys through strain-rate change tests above 1000 C. The yield stresses of all the titanium alloys at temperatures above 1093 C were less than 1% of their ambient temperature values. strain hardening was negligible in the alloys tested at these high temperatures. Extended tensile ductilities of 100 to 200% were observed due to the pronounced strain-rare sensitivity. The rate controlling mechanism for plasticity, based on activation energy and the strain-rate sensitivity measurements, is discussed.

  19. In Situ Neutron Diffraction Studies of Increasing Tension Strains of Superelastic Nitinol

    NASA Astrophysics Data System (ADS)

    Pelton, Alan R.; Clausen, Bjørn; Stebner, Aaron P.

    2015-09-01

    A micromechanical study of the effect of varying amounts of tensile strains on the microstructures and subsequent mechanical behaviors of superelastic Nitinol rods is presented. It is found that strains up to ~8-9 % develop microstructures that assist both forward and reverse transformation relative to un-strained material. This superelastic phenomenon is explained to be analogous to two-way shape memory effect in Nitinol actuation materials. These results provide understanding as to why such "pre-strains" may lead to improvements in subsequent superelastic fatigue life. Beyond 9 %, a drastic change is observed, as large amounts of martensite (75 % and more) are retained in unloaded samples. Thus, a competition between transformation, plasticity, and reorientation is found to give rise to microstructures that inhibit complete transformation. Furthermore, even though similar inelastic strain magnitudes are observed in loading and unloading plateaus, micromechanical mechanisms differ substantially from samples with less pre-strain. For example, in highly pre-strained samples at least half of the plateau strains are due to martensite reorientation, whereas, in low and moderately pre-strained samples nearly the entirety of the plateau strain is due to transformation. We also find that latent heat of plastic flow is larger than latent heat of transformation.

  20. Two interbreeding populations of Saccharomyces cerevisiae strains coexist in cachaça fermentations from Brazil.

    PubMed

    Badotti, Fernanda; Vilaça, Sibelle T; Arias, Armando; Rosa, Carlos A; Barrio, Eladio

    2014-03-01

    In this study, the phylogenetic relationships between cachaça strains of Saccharomyces cerevisiae isolated from different geographical areas in Brazil were obtained on the basis of sequences of one mitochondrial (COX2) and three nuclear (EGT2, CAT8, and BRE5) genes. This analysis allowed us to demonstrate that different types of strains coexist in cachaça fermentations: wine strains, exhibiting alleles related or identical to those present in European wine strains; native strains, containing alleles similar to those found in strains isolated from traditional fermentations from Latin America, North America, Malaysian, Japan, or West Africa; and their intraspecific hybrids or 'mestizo' strains, heterozygous for both types of alleles. Wine strains and hybrids with high proportions of wine-type alleles predominate in southern and southeastern Brazil, where cachaça production coexists with winemaking. The high frequency of 'wine-type' alleles in these regions is probably due to the arrival of wine immigrant strains introduced from Europe in the nearby wineries due to the winemaking practices. However, in north and northeastern states, regions less suited or not suited for vine growing and winemaking, wine-type alleles are much less frequent because 'mestizo' strains with intermediate or higher proportions of 'native-type' alleles are predominant.

  1. Strain characterization of embedded aerospace smart materials using shearography

    NASA Astrophysics Data System (ADS)

    Anisimov, Andrei G.; Müller, Bernhard; Sinke, Jos; Groves, Roger M.

    2015-04-01

    The development of smart materials for embedding in aerospace composites provides enhanced functionality for future aircraft structures. Critical flight conditions like icing of the leading edges can affect the aircraft functionality and controllability. Hence, anti-icing and de-icing capabilities are used. In case of leading edges made of fibre metal laminates heater elements can be embedded between composite layers. However this local heating causes strains and stresses in the structure due to the different thermal expansion coefficients of the different laminated materials. In order to characterize the structural behaviour during thermal loading full-field strain and shape measurement can be used. In this research, a shearography instrument with three spatially-distributed shearing cameras is used to measure surface displacement gradients which give a quantitative estimation of the in- and out-of-plane surface strain components. For the experimental part, two GLARE (Glass Laminate Aluminum Reinforced Epoxy) specimens with six different embedded copper heater elements were manufactured: two copper mesh shapes (straight and S-shape), three connection techniques (soldered, spot welded and overlapped) and one straight heater element with delaminations. The surface strain behaviour of the specimens due to thermal loading was measured and analysed. The comparison of the connection techniques of heater element parts showed that the overlapped connection has the smallest effect on the surface strain distribution. Furthermore, the possibility of defect detection and defect depth characterisation close to the heater elements was also investigated.

  2. Draft Genome Sequence for Caulobacter sp. Strain OR37, a Bacterium Tolerant to Heavy Metals

    PubMed Central

    Utturkar, Sagar M.; Brzoska, Ryann M.; Klingeman, Dawn M.; Epstein, Slava E.; Palumbo, Anthony V.

    2013-01-01

    Caulobacter sp. strain OR37 belongs to the class Alphaproteobacteria and was isolated from subsurface sediments in Oak Ridge, TN. Strain OR37 is noteworthy due to its tolerance to high concentrations of heavy metals, such as uranium, nickel, cobalt, and cadmium, and we present its draft genome sequence here. PMID:23792749

  3. Prediction of thermal strains in fibre reinforced plastic matrix by discretisation of the temperature exposure history

    NASA Astrophysics Data System (ADS)

    Ngoy, E. K.

    2016-07-01

    Prediction of environmental effects on fibre reinforced plastics habitually is made difficult due to the complex variability of the natural service environment. This paper suggests a method to predict thermal strain distribution over the material lifetime by discretisation of the exposure history. Laboratory results show a high correlation between predicted and experimentally measured strain distribution

  4. Self-Repairing Polymer Optical Fiber Strain Sensor

    NASA Astrophysics Data System (ADS)

    Song, Young Jun

    This research develops a self-repairing polymer optical fiber strain sensor for structural health monitoring applications where the sensor network must survive under extreme conditions. Inspired by recent research in self-healing material systems, this dissertation demonstrates a self-repairing strain sensor waveguide, created by self-writing in a photopolymerizable resin system. In an initial configuration, the waveguide sensor was fabricated between two multi-mode (MM) optical fibers via ultraviolet (UV) lightwaves in the UV curable resin and operated as a strain sensor by interrogation of the infrared (IR) power transmission through the waveguide. After failure of the sensor occurred due to loading, the waveguide re-bridged the gap between the two optical fibers through the UV resin. The response of the waveguide sensors was sensitive to the applied strain and repeatable during multiple loading cycles with low observed hysteresis, however was not always monotonic. The strain response of the original sensor and the self-repaired sensor showed similar behaviors. Packaging the sensor in a polymer capillary improved the performance of the sensor by removing previous "no-response" zones. The resulting sensor output was monotonic throughout the measurement range. The hysteresis in the sensor behavior between multiple loading cycles was also significantly reduced. However, a jump in sensor output voltage was observed after the sensor self-repair process, which presents challenges for calibration of the sensor. The sensor configuration was modified to a Fabry-Perot interferometer to improve the sensor response. The measurable strain range was extended through multiple sensor self-repairs, and strain measurements were demonstrated up to 150% applied tensile strain. A hybrid sensor was fabricated by splicing a short segment of MM optical fiber to the input single-mode (SM) optical fiber. The hybrid sensor provided the high quality of waveguide fabrication previously

  5. Forming limit strains of interstitial free-IF steel sheet

    NASA Astrophysics Data System (ADS)

    Bressan, José Divo; Moreira, Luciano Pessanha; Freitas, Maria Carolina dos Santos

    2016-10-01

    behavior during the biaxial stretching of sheet metals. Theoretical predicted curves of local necking limits are plotted in the positive and negative region of MPLS for different defect values fo and λ/μ parameters. Limit strains are obtained from a software developed by the authors. Experimental results of FLC obtained from experiments for IF steel sheets were compared with the theoretical predicted curves: the correlation is reasonable good in the positive quadrant, but the predicted values are above the experimental points in the negative quadrant due to punch friction, non-linear strain path and grid measurements.

  6. Elevated temperature stress strain behavior of beryllium powder product

    SciTech Connect

    Abeln, S.P.; Field, R.; Mataya, M.C.

    1995-09-01

    Several grades of beryllium powder product were tested under isothermal conditions in compression over a temperature range of room temperature to 1000 C and a strain rate range from 0.001 s{sup {minus}1} to 1 s{sup {minus}1}. Samples were compressed to a total strain of 1 (64% reduction in height). It is shown that all the grades are strain rate sensitive and that strain rate sensitivity increases with temperature. Yield points were exhibited by some grades up to a temperature of 500 C, and appeared to be primarily dependent on prior thermal history which determined the availability of mobile dislocations. Serrated flow in the form of stress drops was seen in all the materials tested and was most pronounced at 500 C. The appearance and magnitude of the stress drops were dependent on accumulated strain, strain rate, sample orientation, and composition. The flow stress and shape of the flow curves differed significantly from grade to grade due to variations in alloy content, the size and distribution of BeO particles, aging precipitates, and grain size. The ductile-brittle transition temperature (DBTT) was determined for each grade of material and shown to be dependent on composition and thermal treatment. Structure/property relationships are discussed using processing history, microscopy (light and transmission), and property data.

  7. Growth of highly strained CeO2 ultrathin films

    DOE PAGES

    Shi, Yezhou; Lee, Sang Chul; Monti, Matteo; ...

    2016-11-07

    Large biaxial strain is a promising route to tune the functionalities of oxide thin films. However, large strain is often not fully realized due to the formation of misfit dislocations at the film/substrate interface. In this work, we examine the growth of strained ceria (CeO2) thin films on (001)-oriented single crystal yttria-stabilized zirconia (YSZ) via pulsed-laser deposition. By varying the film thickness systematically between 1 and 430 nm, we demonstrate that ultrathin ceria films are coherently strained to the YSZ substrate for thicknesses up to 2.7 nm, despite the large lattice mismatch (~5%). The coherency is confirmed by both X-raymore » diffraction and high-resolution transmission electron microscopy. This thickness is several times greater than the predicted equilibrium critical thickness. Partial strain relaxation is achieved by forming semirelaxed surface islands rather than by directly nucleating dislocations. In situ reflective high-energy electron diffraction during growth confirms the transition from 2-D (layer-by-layer) to 3-D (island) at a film thickness of ~1 nm, which is further supported by atomic force microscopy. We propose that dislocations likely nucleate near the surface islands and glide to the film/substrate interface, as evidenced by the presence of 60° dislocations. Finally, an improved understanding of growing oxide thin films with a large misfit lays the foundation to systematically explore the impact of strain and dislocations on properties such as ionic transport and redox chemistry.« less

  8. Applications of strained layer superlattices

    NASA Astrophysics Data System (ADS)

    Smith, D. L.; Laurich, B. K.; Mailhiot, C.

    1990-04-01

    Because of different band edge lineups, strain conditions, and growth orientations, various strained layer superlattice (SLS) materials can exhibit qualitatively new physical behavior in their optical properties. Two examples are given of new physical behavior in SLS: strain generated electric fields in polar growth axis superlattices and strained type 2 superlattices. In SLS, large electric fields can be generated by the piezoelectric effect. The fields are largest for SLS with a (111) growth axis; they vanish for SLS with a (100) growth axis. The strain generated electric fields strongly modify the optical properties of the superlattice. Photogenerated electron-hole pairs screen the fields leading to a large nonlinear optical response. Application of an external electric field leads to a large linear electrooptical response. The absorption edge can be either red or blue shifted. Optical studies of (100), (111), and (211) oriented GaInAs/GaAs superlattices confirm the existence of the strain generated electric fields. Small band gap semiconductors are useful for making intrinsic long wavelength infrared detectors. Arbitrarily small band gaps can be reached in the type 2 superlattice InAs/GaSb. However, for band gaps less than 0.1 eV, the layer thicknesses are large and the overlap of electron and hole wavefunctions are small. Thus, the absorption coefficient is too small for useful infrared (IR) detection. Including In in the GaSb introduces strain in he InAs/GaInSb superlattice which shifts the band edges so that small band gaps can be reached in thin layer superlattices. Good absorption at long IR wavelengths is thus achieved.

  9. Magnetic susceptibility, petrofabrics and strain

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham John

    1988-12-01

    Magnetic susceptibility is a non-destructive technique for quantifying the average fabric of a small sample of rock. The interpretation of the magnetic fabric is not always straightforward. However, the principal directions of the magnitude ellipsoid of susceptibility commonly show orientations consistent with the kinematic interpretations of folds, shear zones and other structural features. The directions may correspond with the orientations of strained objects or with the planar-linear mineral orientations. There will usually be multiple mineralogical sources of susceptibility, often involving silicates. If the sources are known, or if the susceptibility can be attributed to a single mineral species, it may be possible to establish a correlation between the strain ellipsoid and the susceptibility ellipsoid. This correlation will be of principal directions in many instances and occasionally there may be a weak correlation of strain magnitudes as well. In other circumstances it may be possible to establish a correlation between changes in susceptibility and the strain. Nevertheless magnetic fabric studies are not routine substitutes for strain analysis. Even where information on strain is not provided, the magnetic fabrics (and subfabrics) yield a measure of the preferred crystallographic orientation or preferred dimensional orientation of the minerals that may be integrated profitably with other petrofabric data. Experimental deformation of certain synthetic aggregates indicates that directions of magnetic susceptibility spin rapidly with advancing strain, especially where the matrix grains undergo crystal-plastic deformation. In certain experiments, simple shear appears to change the intensity of magnetic fabric more effectively than pure shear. Experiments indicate also that the initial anisotropy of a rock-like material is not easily overprinted by deformation whereas field studies are equivocal.

  10. Strain engineered high reflectivity DBRs in the deep UV

    NASA Astrophysics Data System (ADS)

    Franke, A.; Hoffmann, M. P.; Hernandez-Balderrama, L.; Kaess, F.; Bryan, I.; Washiyama, S.; Bobea, M.; Tweedie, J.; Kirste, R.; Gerhold, M.; Collazo, R.; Sitar, Z.

    2016-02-01

    The maximum achievable reflectivity of current III-nitride Bragg reflectors in the UV-C spectral range is limited due to plastic relaxation of thick multilayer structures. Cracking due to a large mismatch of the thermal expansion and lattice constants between AlxGa1-xN/AlyGa1-yN alloys of different composition and the substrate at the heterointerface is the common failure mode. Strain engineering and strain relaxation concepts by the growth on a strain reduced Al0.85Ga0.15N template and the implementation of low temperature interlayers is demonstrated. A significant enhancement of the maximum reflectivity above 97% at a resonance wavelength of 270 nm due to an increase of the critical thickness of our AlN/Al0.65Ga0.35N DBRs to 1.45 μm (25.5 pairs) prove their potential. By comparing the growth of identical Bragg reflectors on different pseudo-templates, the accumulated mismatch strain energy in the DBR, not the dislocation density provided by the template/substrate, was identified to limit the critical thickness. To further enhance the reflectivity low temperature interlays were implemented into the DBR to partially relief the misfit strain. Relaxation is enabled by the nucleation of small surface domains facilitating misfit dislocation injection and glide. Detailed structural and optical investigations will be conducted to prove the influence of the LT-AlN interlayers on the strain state, structural integrity and reflectivity properties. Coherent growth and no structural and optical degradation of the Bragg mirror properties was observed proving the fully applicability of the relaxation concept to fabricate thick high reflectivity DBR and vertical cavity laser structures.

  11. When you pass your due date

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000515.htm When you pass your due date To use the sharing features ... link between you and your baby. As you pass your due date, the placenta may not work ...

  12. Experiments to study strain gage load calibrations on a wing structure at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Monaghan, R. C.; Fields, R. A.

    1973-01-01

    Laboratory experiments were performed to study changes in strain-gage bridge load calibrations on a wing structure heated to temperatures of 200 F, 400 F, and 600 F. Data were also obtained to define the experimental repeatability of strain-gage bridge outputs. Experiments were conducted to establish the validity of the superposition of bridge outputs due to thermal and mechanical loads during a heating simulation of Mach 3 flight. The strain-gage bridge outputs due to load cycle at each of the above temperature levels were very repeatable. A number of bridge calibrations were found to change significantly as a function of temperature. The sum of strain-gage bridge outputs due to individually applied thermal and mechanical loads compared well with that due to combined or superimposed loads. The validity of superposition was, therefore, established.

  13. Fabric strain sensor integrated with CNPECs for repeated large deformation

    NASA Astrophysics Data System (ADS)

    Yi, Weijing

    Flexible and soft strain sensors that can be used in smart textiles for wearable applications are much desired. They should meet the requirements of low modulus, large working range and good fatigue resistance as well as good sensing performances. However, there were no commercial products available and the objective of the thesis is to investigate fabric strain sensors based on carbon nanoparticle (CNP) filled elastomer composites (CNPECs) for potential wearing applications. Conductive CNPECs were fabricated and investigated. The introduction of silicone oil (SO) significantly decreased modulus of the composites to less than 1 MPa without affecting their deformability and they showed good stability after heat treatment. With increase of CNP concentration, a percolation appeared in electrical resistivity and the composites can be divided into three ranges. I-V curves and impedance spectra together with electro-mechanical studies demonstrated a balance between sensitivity and working range for the composites with CNP concentrations in post percolation range, and were preferred for sensing applications only if the fatigue life was improved. Due to the good elasticity and failure resist property of knitted fabric under repeated extension, it was adopted as substrate to increase the fatigue life of the conductive composites. After optimization of processing parameters, the conductive fabric with CNP concentration of 9.0CNP showed linear I-V curves when voltage is in the range of -1 V/mm and 1 V/mm and negligible capacitive behavior when frequency below 103 Hz even with strain of 60%. It showed higher sensitivity due to the combination of nonlinear resistance-strain behavior of the CNPECs and non-even strain distribution of knitted fabric under extension. The fatigue life of the conductive fabric was greatly improved. Extended on the studies of CNPECs and the coated conductive fabrics, a fabric strain sensor was designed, fabricated and packaged. The Young's modulus of

  14. The Due Care Paradigm of School Leadership.

    ERIC Educational Resources Information Center

    Osborne, Bill

    The Due Care paradigm for the successful restructuring of organizations is presented in this paper, with attention to the paradigm's role in creating a fundamental shift from vertical (top/down) decision making to shared governance. The first section explains how due care is linked to three legal terms in tort law--substantive due process, due…

  15. 29 CFR 4007.11 - Due dates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Due dates. (a) In general. For flat-rate and variable-rate premiums, the premium filing due date for... variable-rate premium payment must be made by the last day of the sixteenth full calendar month following... payment year. (ii) The due date for the variable-rate premium required by § 4006.3(b) of this chapter...

  16. Two-strain competition in quasineutral stochastic disease dynamics

    NASA Astrophysics Data System (ADS)

    Kogan, Oleg; Khasin, Michael; Meerson, Baruch; Schneider, David; Myers, Christopher R.

    2014-10-01

    We develop a perturbation method for studying quasineutral competition in a broad class of stochastic competition models and apply it to the analysis of fixation of competing strains in two epidemic models. The first model is a two-strain generalization of the stochastic susceptible-infected-susceptible (SIS) model. Here we extend previous results due to Parsons and Quince [Theor. Popul. Biol. 72, 468 (2007), 10.1016/j.tpb.2007.04.002], Parsons et al. [Theor. Popul. Biol. 74, 302 (2008), 10.1016/j.tpb.2008.09.001], and Lin, Kim, and Doering [J. Stat. Phys. 148, 646 (2012), 10.1007/s10955-012-0479-9]. The second model, a two-strain generalization of the stochastic susceptible-infected-recovered (SIR) model with population turnover, has not been studied previously. In each of the two models, when the basic reproduction numbers of the two strains are identical, a system with an infinite population size approaches a point on the deterministic coexistence line (CL): a straight line of fixed points in the phase space of subpopulation sizes. Shot noise drives one of the strain populations to fixation, and the other to extinction, on a time scale proportional to the total population size. Our perturbation method explicitly tracks the dynamics of the probability distribution of the subpopulations in the vicinity of the CL. We argue that, whereas the slow strain has a competitive advantage for mathematically "typical" initial conditions, it is the fast strain that is more likely to win in the important situation when a few infectives of both strains are introduced into a susceptible population.

  17. Vacancy-mediated diffusion in biaxially strained Si

    NASA Astrophysics Data System (ADS)

    Caliste, Damien; Rushchanskii, Konstantin Z.; Pochet, Pascal

    2011-01-01

    We present an analysis of stress-enhanced vacancy-mediated diffusion in biaxially deformed Si (100) films as measured by the strain derivative (Q') of the activation energy. The strain dependence of Q' is demonstrated by means of a reanalysis of previously published experimental data, which both take into account the temperature dependence of and highlight the differences between tensile and compressive stress. Based on ab initio calculations, we predict that Q' in pure silicon is higher under compressive conditions due to a broken degeneracy of the split-vacancy configuration.

  18. High strain-rate model for fiber-reinforced composites

    SciTech Connect

    Aidun, J.B.; Addessio, F.L.

    1995-07-01

    Numerical simulations of dynamic uniaxial strain loading of fiber-reinforced composites are presented that illustrate the wide range of deformation mechanisms that can be captured using a micromechanics-based homogenization technique as the material model in existing continuum mechanics computer programs. Enhancements to the material model incorporate high strain-rate plastic response, elastic nonlinearity, and rate-dependent strength degradation due to material damage, fiber debonding, and delamination. These make the model relevant to designing composite structural components for crash safety, armor, and munitions applications.

  19. Direct in vivo strain measurements in human bone-a systematic literature review.

    PubMed

    Al Nazer, R; Lanovaz, J; Kawalilak, C; Johnston, J D; Kontulainen, S

    2012-01-03

    Bone strain is the governing stimuli for the remodeling process necessary in the maintenance of bone's structure and mechanical strength. Strain gages are the gold standard and workhorses of human bone experimental strain analysis in vivo. The objective of this systematic literature review is to provide an overview for direct in vivo human bone strain measurement studies and place the strain results within context of current theories of bone remodeling (i.e. mechanostat theory). We employed a standardized search strategy without imposing any time restriction to find English language studies indexed in PubMed and Web of Science databases that measured human bone strain in vivo. Twenty-four studies met our final inclusion criteria. Seven human bones were subjected to strain measurements in vivo including medial tibia, second metatarsal, calcaneus, proximal femur, distal radius, lamina of vertebra and dental alveolar. Peak strain magnitude recorded was 9096 με on the medial tibia during basketball rebounding and the peak strain rate magnitude was -85,500 με/s recorded at the distal radius during forward fall from standing, landing on extended hands. The tibia was the most exposed site for in vivo strain measurements due to accessibility and being a common pathologic site of stress fracture in the lower extremity. This systematic review revealed that most of the strains measured in vivo in different bones were generally within the physiological loading zone defined by the mechanostat theory, which implies stimulation of functional adaptation necessary to maintain bone mechanical integrity.

  20. Characterization of different food-isolated Enterococcus strains by MALDI-TOF mass fingerprinting.

    PubMed

    Quintela-Baluja, Marcos; Böhme, Karola; Fernández-No, Inmaculada C; Morandi, Stefano; Alnakip, Mohammed E; Caamaño-Antelo, Sonia; Barros-Velázquez, Jorge; Calo-Mata, Pilar

    2013-08-01

    Enterococcus is a controversial genus due to its great variability; this genus includes pathogenic strains, spoilage strains, and apparently safe strains including some probiotic strains. Previous studies focused on the characterization of strains of Enterococcus spp. involved in nosocomial infections. However, little research has been conducted on Enterococcus strains in foodstuffs. In the present work, 36 strains of different species of Enterococcus have been characterized by means of MALDI-TOF MS, resulting in highly specific mass spectral fingerprints. Characteristic peak masses common to certain bacterial species of Enterococcus have been identified. Thus, a peak at m/z 4426 ± 1 was assigned as a genus-specific biomarker. In addition, phyloproteomic relationships based on the mass spectral data were compared to the results of a phylogenetic analysis based on the 16S rRNA gene sequence. A better grouping at the species level was observed in the phyloproteomic tree, especially for the Enterococcus faecium group. Presumably, the assortment of some strains or ecotypes could be related to their ecological niche specialization. The approach described in this study leads the way toward the rapid and specific identification of different strains and species of Enterococcus in food based on molecular protein markers, aiming at the early detection of pathogenic strains and strains implicated in food poisoning or food spoilage.

  1. Molecular characterization of Vibrio cholerae O1 strains isolated during cholera outbreaks in Guinea-Bissau.

    PubMed Central

    Dalsgaard, A; Mortensen, H F; Mølbak, K; Dias, F; Serichantalergs, O; Echeverria, P

    1996-01-01

    In the present study, 19 strains of Vibrio cholerae O1 biotype El Tor isolated during outbreaks of cholera in Guinea-Bissau in 1987, 1994, and 1995 were characterized to investigate a possible epidemiological relationship among the isolates. On the basis of ribotyping with the restriction enzyme BglI, 5 strains isolated in 1987 showed two closely related ribotypes, while 14 strains isolated in 1994 and 1995 showed the same ribotype that was distinct from the ribotypes of strains isolated in 1987. Southern blot hybridization of BglI-digested genomic DNA with a cholera toxin probe demonstrated that the strains isolated in 1987 showed an identical cholera toxin genotype, whereas O1 strains isolated in 1994 and 1995 showed the same genotype that was distinct from the genotype of strains isolated in 1987. These results were supported by the results of antibiotic susceptibility testing, in which strains isolated in 1987 showed resistance to polymyxin B only, while each of the strains from 1994 and 1995 showed resistance to polymyxin B, trimethoprim-sulfamethoxazole, and the vibriostatic agent O/129. Although our results are based on a limited number of V. cholerae O1 strains, they suggest that the epidemic in Guinea-Bissau in 1994 and 1995 was due to the introduction of a new strain to the country. PMID:8727901

  2. Inelastic strain rate in the seismogenic layer of Kyushu Island, Japan

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Nishimura, Takuya; Ohkura, Takahiro

    2016-12-01

    Seismic activity is associated with crustal stress relaxation, creating inelastic strain in a medium due to faulting. Inelastic strain affects the stress field around a weak body and causes stress concentration around the body, because the body itself has already released stress. Therefore, the understanding of inelastic deformation is important as it generates earthquakes. We investigated average inelastic strain in a spatial bin of Kyushu Island, Japan, and obtained the inelastic strain rate distribution associated with crustal earthquakes, based on the analysis of fault plane solutions and seismic moments. Large inelastic strains (>10-7 year-1) were found in the Beppu-Shimabara area, located in the center of Kyushu Island. The strain rate tensor was similar to that of the stress tensor except the absolute value in the area, implying that the inelastic strain was controlled by the stress field. The 2016 Kumamoto earthquake sequence (maximum magnitude 7.3) occurred in the Beppu-Shimabara area, with the major earthquakes located around the high inelastic strain rate area. Inelastic strain in the volume released the stress. In addition, the inelastic strain created an increment of stress around the volume. This indicates that the spatial heterogeneity of inelastic strain might concentrate stress.[Figure not available: see fulltext.

  3. Measuring mine roof bolt strains

    DOEpatents

    Steblay, Bernard J.

    1986-01-01

    A mine roof bolt and a method of measuring the strain in mine roof bolts of this type are disclosed. According to the method, a flat portion on the head of the mine roof bolt is first machined. Next, a hole is drilled radially through the bolt at a predetermined distance from the bolt head. After installation of the mine roof bolt and loading, the strain of the mine roof bolt is measured by generating an ultrasonic pulse at the flat portion. The time of travel of the ultrasonic pulse reflected from the hole is measured. This time of travel is a function of the distance from the flat portion to the hole and increases as the bolt is loaded. Consequently, the time measurement is correlated to the strain in the bolt. Compensation for various factors affecting the travel time are also provided.

  4. Quantification of muscle fiber strain during in vivo repetitive stretch-shortening cycles.

    PubMed

    Butterfield, Timothy A; Herzog, Walter

    2005-08-01

    Muscles subjected to lengthening contractions exhibit evidence of subcellular disruption, arguably a result of fiber strain magnitude. Due to the difficulty associated with measuring fiber strains during lengthening contractions, fiber length estimates have been used to formulate relationships between the magnitude of injury and mechanical measures such as fiber strain. In such protocols, the series compliance is typically minimized by removing the distal tendon and/or preactivating the muscle. These in vitro and in situ experiments do not represent physiological contractions well where fiber strain and muscle strain may be disassociated; thus the mechanisms of in vivo muscle injury remain elusive. The purpose of this paper was to quantify fiber strains during lengthening contractions in vivo and assess the potential role of fiber strain in muscle injury following repetitive stretch-shortening cycles. Using intact New Zealand White rabbit dorsiflexors, fiber strain and joint torque were measured during 50 stretch-shortening cycles. We were able to show that fiber length changes are disassociated from muscle tendon unit length changes and that complex fiber dynamics during these cycles prevent easy estimates of fiber strains. In addition, fiber strains vary, depending on how they are defined, and vary from repetition to repetition, thereby further complicating the potential relationship between muscle injury and fiber strain. We conclude from this study that, during in vivo stretch-shortening cycles, the relationship between fiber strain and muscle injury is complex. This is due, in part, to temporal effects of repeated loading on fiber strain magnitude that may be explained by an increasing compliance of the contractile element as exercise progresses.

  5. Genetic engineering using fungal flavohemoglobin for constructing Pseudomonas stutzeri strain emitting less nitrous oxide.

    PubMed

    Takaya, Naoki; Shoun, Hirofumi

    2002-01-01

    Most denitrifiers produce the greenhouse gas nitrous oxide (N2O) due to insufficient anaerobiosis. We constructed a recombinant Pseudomonas stutzeri strain producing Fusarium oxysporum flavohemoglobin (fhb) and found that it emitted less N2O than the wild-type strain under aerobic and anaerobic conditions. The rate of N2 production was higher than in the wild-type strain after the depletion of oxygen in culture, suggesting that fhb enhanced the reduction of N2O to N2. The strain is the first recombinant bacterial denitrifier that reduces N2O production.

  6. Combined diffusion and strain tensor MRI reveals a heterogeneous, planar pattern of strain development during isometric muscle contraction.

    PubMed

    Englund, Erin K; Elder, Christopher P; Xu, Qing; Ding, Zhaohua; Damon, Bruce M

    2011-05-01

    The purposes of this study were to create a three-dimensional representation of strain during isometric contraction in vivo and to interpret it with respect to the muscle fiber direction. Diffusion tensor MRI was used to measure the muscle fiber direction of the tibialis anterior (TA) muscle of seven healthy volunteers. Spatial-tagging MRI was used to measure linear strains in six directions during separate 50% maximal isometric contractions of the TA. The strain tensor (E) was computed in the TA's deep and superficial compartments and compared with the respective diffusion tensors. Diagonalization of E revealed a planar strain pattern, with one nonzero negative strain (ε(N)) and one nonzero positive strain (ε(P)); both strains were larger in magnitude (P < 0.05) in the deep compartment [ε(N) = -40.4 ± 4.3%, ε(P) = 35.1 ± 3.5% (means ± SE)] than in the superficial compartment (ε(N) = -24.3 ± 3.9%, ε(P) = 6.3 ± 4.9%). The principal shortening direction deviated from the fiber direction by 24.0 ± 1.3° and 39.8 ± 6.1° in the deep and superficial compartments, respectively (P < 0.05, deep vs. superficial). The deviation of the shortening direction from the fiber direction was due primarily to the lower angle of elevation of the shortening direction over the axial plane than that of the fiber direction. It is concluded that three-dimensional analyses of strain interpreted with respect to the fiber architecture are necessary to characterize skeletal muscle contraction in vivo. The deviation of the principal shortening direction from the fiber direction may relate to intramuscle variations in fiber length and pennation angle.

  7. Invasive infection in an acute myeloblastic leukemia patient due to triazole-resistant Candida tropicalis.

    PubMed

    de Carvalho Parahym, Ana Maria Rabelo; da Silva, Carolina Maria; Leão, Mariele Porto Carneiro; Macario, Michele Chianca; Filho, Gustavo Antônio da Trindade Meira Henriques; de Oliveira, Neiva Tinti; Neves, Rejane Pereira

    2011-11-01

    Non-albicans Candida species are being increasingly reported as causes of nosocomial fungal infections. For example, invasive candidiasis caused by C. tropicalis has been associated with hematologic malignancies. In this study, we report a fatal case of fungemia and a possible urinary and pulmonary infection in a leukemia patient that was due to a strain of C. tropicalis resistant to 2 triazole antifungals.

  8. Flow sensor using optical fiber strain gauges

    NASA Astrophysics Data System (ADS)

    Schmitt, Nicolas F.; Morgan, R.; Scully, Patricia J.; Lewis, Elfed; Chandy, Rekha

    1995-09-01

    A novel technique for the measurement of air flow velocity using an optical fiber sensor is reported. The sensor measures the deformation of a rubber cantilever beam when subjected to the stresses induced by drag forces in the presence of the airflow. Tests performed in a wind tunnel have indicated a sensitivity of 2 (mu) /(m/s). A qualitative model based on fiber mode propagation has been developed which allows the sensor to be characterized in terms of optical losses. A single 1 mm diameter polymer fiber is mounted on the rectangular section rubber cantilever (section 14 mm by 6 mm) and six grooves are etched into the fiber which extend into the core of the fiber. As the beam deviates the surface deforms (stretches or contracts) and the fiber is subjected to strain. As the strain is increased the grooves become wider and the amount of light transmitted through the fiber is reduced due to increased losses. The sensor described has all the advantages of optical fiber sensors including electrical noise immunity and intrinsic safety for use in hazardous environments. However, its simple construction, robustness, versatility for a number of different fluid applications, as well as relatively low cost make it attractive for use in a wide variety of measurement applications e.g. wind velocity measurement where airborne moisture or chemicals are present.

  9. Photoacoustic spectroscopy of Entamoeba histolytica strains

    NASA Astrophysics Data System (ADS)

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Silva, E. F.; Orozco, E.; de Menezes, L. F.; Vargas, H.

    2005-06-01

    Pathogenic and non-pathogenic strains of E. histolytica are studied using photoacoustic spectroscopy. It is shown that the pathogenic strain presents a spectrum similar to that of iron sulfur proteins. The non-pathogenic strain does not show any relevant absorption at the studied wavelength range. The differences observed between the optical absorption spectra of both strains opens the possibility of using photoacoustic spectroscopy as a reliable and simple technique to identify different types of E. histolytica strains.

  10. Characterization of strains of Corynebacterium bovis.

    PubMed Central

    Brooks, B W; Barnum, D A

    1984-01-01

    The biochemical and morphological characteristics of 104 strains of Corynebacterium bovis isolated from bovine milk samples and the C. bovis reference strain were found to be uniform. Valuable criteria for identification were presence of catalase and oxidase, production of acid from glucose and fructose and a requirement for enriched basal media. Six strains of human and three strains of bovine origin were found to be inconsistent with the reference strain. PMID:6722650

  11. Engineering Clostridium Strain to Accept Unmethylated DNA

    PubMed Central

    Dong, Hongjun; Zhang, Yanping; Dai, Zongjie; Li, Yin

    2010-01-01

    It is difficult to genetically manipulate the medically and biotechnologically important genus Clostridium due to the existence of the restriction and modification (RM) systems. We identified and engineered the RM system of a model clostridial species, C. acetobutylicum, with the aim to allow the host to accept the unmethylated DNA efficiently. A gene CAC1502 putatively encoding the type II restriction endonuclease Cac824I was identified from the genome of C. acetobutylicum DSM1731, and disrupted using the ClosTron system based on group II intron insertion. The resulting strain SMB009 lost the type II restriction endonuclease activity, and can be transformed with unmethylated DNA as efficiently as with methylated DNA. The strategy reported here makes it easy to genetically modify the clostridial species using unmethylated DNA, which will help to advance the understanding of the clostridial physiology from the molecular level. PMID:20161730

  12. Brittle dynamic damage due to earthquake rupture

    NASA Astrophysics Data System (ADS)

    Bhat, Harsha; Thomas, Marion

    2016-04-01

    The micromechanical damage mechanics formulated by Ashby and Sammis, 1990, and generalized by Deshpande and Evans 2008 has been extended to allow for a more generalized stress state and to incorporate an experimentally motivated new crack growth (damage evolution) law that is valid over a wide range of loading rates. This law is sensitive to both the crack tip stress field and its time derivative. Incorporating this feature produces additional strain-rate sensitivity in the constitutive response. The model is also experimentally verified by predicting the failure strength of Dionysus-Pentelicon marble over wide range of strain rates. We then implement this constitutive response to understand the role of dynamic brittle off-fault damage on earthquake ruptures. We show that off-fault damage plays an important role in asymmetry of rupture propagation and is a source of high-frequency ground motion in the near source region.

  13. Finite element stress analysis of polymers at high strains

    NASA Technical Reports Server (NTRS)

    Durand, M.; Jankovich, E.

    1973-01-01

    A numerical analysis is presented for the problem of a flat rectangular rubber membrane with a circular rigid inclusion undergoing high strains due to the action of an axial load. The neo-hookean constitutive equations are introduced into the general purpose TITUS program by means of equivalent hookean constants and initial strains. The convergence is achieved after a few iterations. The method is not limited to any specific program. The results are in good agreement with those of a company sponsored photoelastic stress analysis. The theoretical and experimental deformed shapes also agree very closely with one another. For high strains it is demonstrated that using the conventional HOOKE law the stress concentration factor obtained is unreliable in the case of rubberlike material.

  14. Tensile stress-strain behavior of hybrid composite laminates

    NASA Technical Reports Server (NTRS)

    Kennedy, J. M.

    1983-01-01

    A study was made of the stress-strain response of several hybrid laminates, and the damage was correlated with nonlinear stress-strain response and ultimate strength. The fibers used in the laminates were graphite, S-glass, and Kevlar. Some laminates with graphite fibers had perforated Mylar film between plies, which lowered the interlaminar bond strength. The laminate configurations were chosen to be like those of buffer strips in large panels and fracture coupons. Longitudinal and transverse specimens were loaded in tension to failure. Some specimens were radiographed to reveal damage due to edge effects. Stress-strain response is discussed in terms of damage shown by the radiographs. Ultimate strengths are compared with simple failure criteria, one of which account for damage.

  15. Piezoresistive Strain Sensors Made from Carbon Nanotubes Based Polymer Nanocomposites

    PubMed Central

    Alamusi; Hu, Ning; Fukunaga, Hisao; Atobe, Satoshi; Liu, Yaolu; Li, Jinhua

    2011-01-01

    In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity. PMID:22346667

  16. Ignition, Burning, and Extinction of a Strained Fuel Strip

    NASA Technical Reports Server (NTRS)

    Selerland, T.; Karagozian, A. R.

    1996-01-01

    Flame structure and ignition and extinction processes associated with a strained fuel strip are explored numerically using detailed transport and complex kinetics for a propane-air reaction. Ignition modes are identified that are similar to those predicted by one-step activation energy asymptotics, i.e., modes in which diffusion flames can ignite as independent or dependent interfaces, and modes in which single premixed or partially premixed flames ignite. These ignition modes are found to be dependent on critical combinations of strain rate, fuel strip thickness, and initial reactant temperatures. Extinction in this configuration is seen to occur due to fuel consumption by adjacent flames, although viscosity is seen to have the effect of delaying extinction by reducing the effective strain rate and velocity field experienced by the flames.

  17. Remote Strain Sensing of CFRP Using Microwave Frequency Domain Reflectometry

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    NASA's Advanced Composites Project is investigating technologies that increase automated remote inspection of aircraft composite structures. Therefore, microwave Frequency Domain Reflectometry (FDR) is being investigated as a method of enabling rapid remote measurement of strain occurring at the first ply of a composite fiber reinforced polymer (CFRP) structure using Radio Frequency (RF) Electro-Magnetic (EM) radiation. While microwave reflectometry has been used to detect disbonds in CFRP structures, its use in detecting strain has been limited. This work will present data demonstrating the measurement of the reactance changes due to loading conditions that are indicative of strain in a CFRP structure. In addition, the basic EM signature will be presented along with an analysis of temperature and humidity effects.

  18. Flexible and printable paper-based strain sensors for wearable and large-area green electronics.

    PubMed

    Liao, Xinqin; Zhang, Zheng; Liao, Qingliang; Liang, Qijie; Ou, Yang; Xu, Minxuan; Li, Minghua; Zhang, Guangjie; Zhang, Yue

    2016-07-14

    Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control.

  19. Detection of pap-, sfa- and afa-specific DNA sequences in Escherichia coli strains isolated from extraintestinal material.

    PubMed

    Bogyiová, E; Kmetová, M; Biros, E; Siegfried, L

    2002-01-01

    P-fimbriae, S-fimbriae and AFA-adhesins are virulence factors responsible for adherence of Escherichia coli strains to extraintestinal host-cell surface. Detection of pap-, sfa- and afa-specific sequences performed by PCR revealed 74% pap+, 65% sfa+, and 8.3% afa+ strains in a group of 84 extraintestinal E. coli isolates. Detection in a group of fecal strains showed 29% pap+, 21% sfa+ and 4% afa+ strains. pap together with sfa were found as the most frequent combination (56%) among extraintestinal isolates probably due to localization of pap- and sfa-operons on a common pathogenicity island. The occurrence of afa-specific sequence among 56 urine strains was 11%, although no afa+ strain was detected among 28 gynecological isolates. No strains with detected adhesin operons were found among twenty (24%) extraintestinal E. coli strains.

  20. Complete genome analysis of three live attenuated Rinderpest virus vaccine strains derived through serial passages in different culture systems.

    PubMed

    Jeoung, Hye-Young; Lee, Myoung-Heon; Yeh, Jung-Yong; Lim, Ji-Ae; Lim, Seong-In; Oem, Jae-Ku; Song, Jae-Young; Lee, Won-Ha; Park, Jong-Hwan; An, Dong-Jun

    2012-12-01

    The genomes of three South Korean Rinderpest virus vaccine strains (L72, LA77, and LA96) were analyzed in order to investigate their genetic variability. These three vaccine strains were all derived from the same virus strain origin (Fusan) through repeated passages in different culture systems. The full genome length of the three strains was 15,882 nucleotides, and the sequence similarity between the three South Korean RPV strains at the nucleotide level was 98.1 to 98.9%. The genetic distance between Nakamura III, L72, LA77, LA96, and LATC06 and the Kabete strain was greater than that between the Fusan and Kabete strains for the P, V, and C genes. The difference in pathogenicity among these strains might be due to the V gene, which has a positive (>1) selection ratio based on the analysis of synonymous (dS) and nonsynonymous (dN) substitution rates (dN/dS ratio [ω]).

  1. Characterization of nanoscale local lattice strains in silicon CMOS devices by TEM/CBED

    NASA Astrophysics Data System (ADS)

    Huang, Jiang

    Strained-Si technology has become one of the leading approaches to further improve the performance of the metal-oxide-semiconductor field effect transistors (MOSFETs) as traditional device scaling faces its physical limitation. In particular, mechanical strain induced in the Si channel region is used to increase the carrier mobility and the transistor drive current. To be able to understand and engineer the local lattice strain incorporated in the nanoscale device region, a strain measurement technique with high spatial resolution and high sensitivity is essential. Currently, transmission electron microscope (TEM)/convergent beam electron diffraction (CBED) is the only method to measure local changes in lattice parameters due to strain in advanced CMOS devices, because this technique provides nanometer spatial resolution and strain sensitivity on the order of 10-4. In this study, a novel experimental methodology is developed to measure the strain effectively and efficiently. Site-specific TEM samples are prepared by focused ion beam (FIB) with controlled thickness. Zone axes such as <230>, <340>, <560> and <910> are evaluated for obtaining CBED patterns. The specimen-tilt projection and dynamical effects related to the zone axis are discussed. CBED pattern simulation and matching procedures are explained to extract the strain tensors. The accuracy of the strain measurement depends on the clarity of the CBED pattern, which can be improved by using an energy-filter or sample cooling stage. The direct strain measurements are performed in sub-100 nm CMOS devices with either structure-induced or process-induced strains. It is found that the compressive strains are induced when the shallow trench structure (STI) is filled with isolation films. The compressive strains on the order of 10 -3 are observed under the gate region in a Si <110> PMOS transistor with a 37 nm gate length. One-dimensional quantitative strain-mapping is demonstrated using the nanometer probe. The

  2. Chronic occupational repetitive strain injury.

    PubMed Central

    O'Neil, B. A.; Forsythe, M. E.; Stanish, W. D.

    2001-01-01

    OBJECTIVE: To review common repetitive strain injuries (RSIs) that occur in the workplace, emphasizing diagnosis, treatment, and etiology of these conditions. QUALITY OF EVIDENCE: A MEDLINE search from January 1966 to June 1999 focused on articles published since 1990 because RSIs are relatively new diagnoses. MeSH headings that were explored using the thesaurus included "cumulative trauma disorder," "overuse injury," and "repetitive strain injury." The search was limited to English articles only, and preference was given to randomized controlled trials. MAIN MESSAGE: Repetitive strain injuries result from repeated stress to the body's soft tissue structures including muscles, tendons, and nerves. They often occur in patients who perform repetitive movements either in their jobs or in extracurricular activities. Common RSIs include tendon-related disorders, such as rotator cuff tendonitis, and peripheral nerve entrapment disorders, such as carpal tunnel syndrome. A careful history and physical examination often lead to the diagnosis, but newer imaging techniques, such as magnetic resonance imaging and ultrasound, can help in refractory cases. Conservative management with medication, physiotherapy, or bracing is the mainstay of treatment. Surgery is reserved for cases that do not respond to treatment. CONCLUSION: Repetitive strain injury is common; primary care physicians must establish a diagnosis and, more importantly, its relationship to occupation. Treatment can be offered by family physicians who refer to specialists for cases refractory to conservative management. PMID:11228032

  3. Trials with a Strain Gauge.

    ERIC Educational Resources Information Center

    Auty, Geoff

    1996-01-01

    Describes an attempt to match the goals of the practical demonstration of the use of a strain gauge and the technical applications of science and responding to student questions in early trials, while keeping within the level of electronics in advanced physics. (Author/JRH)

  4. Bacteriocins and novel bacterial strains.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry is thought to be a significant source of Campylobacter in human disease. We evaluated anti-Campylobacter activity among 365 Bacillus and Paenibacillus isolates from poultry. One novel antagonistic Bacillus circulans and three Paenibacillus polymyxa strains were identified and further studi...

  5. Extreme Temperature Strain Measurement System

    DTIC Science & Technology

    1990-08-01

    Electrix Industries, Inc., P.O. Box 306, Lombard, IL 60148, Phone (312) 627-6802 38 Foil Strain gages. ° HiTEC Corp., Nardone Industrial Park...Planer Ltd., CERL-Planer Capacitive Transducer, Windmill Road, Sunbury -on- Thames, Middx., England, Phone: Sunbury 86262-3-4-5 • HiTEC Corp., Nardone

  6. Temperature affects the morphology and calcification of Emiliania huxleyi strains

    NASA Astrophysics Data System (ADS)

    Rosas-Navarro, Anaid; Langer, Gerald; Ziveri, Patrizia

    2016-05-01

    The global warming debate has sparked an unprecedented interest in temperature effects on coccolithophores. The calcification response to temperature changes reported in the literature, however, is ambiguous. The two main sources of this ambiguity are putatively differences in experimental setup and strain specificity. In this study we therefore compare three strains isolated in the North Pacific under identical experimental conditions. Three strains of Emiliania huxleyi type A were grown under non-limiting nutrient and light conditions, at 10, 15, 20 and 25 °C. All three strains displayed similar growth rate versus temperature relationships, with an optimum at 20-25 °C. Elemental production (particulate inorganic carbon (PIC), particulate organic carbon (POC), total particulate nitrogen (TPN)), coccolith mass, coccolith size, and width of the tube element cycle were positively correlated with temperature over the sub-optimum to optimum temperature range. The correlation between PIC production and coccolith mass/size supports the notion that coccolith mass can be used as a proxy for PIC production in sediment samples. Increasing PIC production was significantly positively correlated with the percentage of incomplete coccoliths in one strain only. Generally, coccoliths were heavier when PIC production was higher. This shows that incompleteness of coccoliths is not due to time shortage at high PIC production. Sub-optimal growth temperatures lead to an increase in the percentage of malformed coccoliths in a strain-specific fashion. Since in total only six strains have been tested thus far, it is presently difficult to say whether sub-optimal temperature is an important factor causing malformations in the field. The most important parameter in biogeochemical terms, the PIC : POC ratio, shows a minimum at optimum growth temperature in all investigated strains. This clarifies the ambiguous picture featuring in the literature, i.e. discrepancies between PIC : POC

  7. Pediatric Sialadenosis Due to Valproic Acid.

    PubMed

    Derin, Hatice; Derin, Serhan; Oltulu, Pembe; Özbek, Orhan; Çaksen, Hüseyin

    2016-12-23

    Sialadenosis is a rare entity characterized by bilateral diffuse, painless swelling of the parotid glands. Its etiology is not clear; however, it may occur due to adverse effects of some drugs. To our knowledge, sialadenosis due to valproic acid has not been reported in the literature up to date in any child. In this article, the authors presented a child who developed sialadenosis due to valproic acid, and improved after stopping use of the drug.

  8. Modelling of elastoplastic damage in concrete due to desiccation shrinkage

    NASA Astrophysics Data System (ADS)

    Bourgeois, F.; Burlion, N.; Shao, J. F.

    2002-07-01

    We present a numerical modelling of elastoplastic damage due to drying shrinkage of concrete in the framework of mechanics of partially saturated porous media. An elastoplastic model coupled with isotropic damage is first formulated. Two plastic flow mechanisms are involved, controlled by applied stress and suction, respectively. A general concept of net effective stress is used in take into account effects of capillary pressure and material damage on stress-controlled plastic deformation. Damage evolution depends both on elastic and plastic strains. The model's parameters are determined or chosen from relevant experimental data. Comparisons between numerical simulations and experimental data are presented to show the capacity of model to reproduce mains features of concrete behaviour under mechanical loading and during drying shrinkage of concrete. An example of application concerning drying of a concrete wall is finally presented. The results obtained allow to show potential capacity of proposed model for numerical modelling of complex coupling processes in concrete structures.

  9. MORPHOLOGICAL ABERRATION OF ARTHROBACTER GLOBIFORMIS CELLS DUE TO BIOTIN DEFICIENCY.

    PubMed

    CHAN, E C

    1964-03-01

    Chan, E. C. S. (University of New Brunswick, Fredericton, New Brunswick, Canada). Morphological aberration of Arthrobacter globiformis cells due to biotin deficiency. J. Bacteriol. 87:641-651. 1964.-Morphological aberration of Arthrobacter globiformis strain 425 was shown to occur during growth in a chemically defined medium without added biotin. Such aberrant cells could revert back to normal coccoid forms upon inoculation into fresh medium supplemented with the vitamin. This abnormal cellular development occurred even when there was good growth (turbidity) or increase in total cell mass. Light photomicrographs of negative and cell-wall stains of the organism at different times of the morphological growth cycle are presented in support of these observations. The relationship between cellular aberration and the biochemical role of biotin is briefly discussed.

  10. Lattice strains and polarized luminescence in homoepitaxial growth of a-plane ZnO

    NASA Astrophysics Data System (ADS)

    Matsui, Hiroaki; Tabata, Hitoshi

    2012-12-01

    In-plane lattice strains in a-plane zinc oxide (ZnO) homoepitaxial layers were selectively introduced by changing substrate type and growth conditions. Strain-free layers were observed when using a Crystec ZnO substrate, which resulted in atomically flat surfaces with nano-facets consisting of the m-plane (10-10) at atomic scale. In contrast, ZnO layers on Goodwill ZnO substrates possessed in-plane lattice strains due to generation of basal-plane stacking faults. The degree of lattice strains was systematically changed by the oxygen pressure, which clarified the close correlation between photoluminescence (PL) polarization and lattice strains. The polarization ratio of PL enhanced with the lattice strains.

  11. [Antibiotic resistance of Shigella strains isolated in Cádiz (author's transl)].

    PubMed

    García Martos, P; Marín Casanova, P; García Herruzo, J; Fernández Gutiérrez del Alamo, C

    1980-12-15

    The incidence of shigellosis at the Residencia Sanitaria Fernando Zamacola (Cáciz, Spain) and the antibiotic sensitivity of 94 strains of Shigella sonnei and 40 strains of Shigella flexneri, isolated during the year 1979, has been studied taking into account the present status of strain resistance to the major antibiotics. Three epidemic bouts of shigellosis were detected: one in february by Shigella sonnei (16 cases), and two others in august-september and november due to Shigella flexneri (43 and 29 cases). Children 2 to 5 years old had the highest incidence of Shigella infection. Almost all strains isolated were resistant to the sulphonamides (99.77%). Ampicillin and chloramphenicol had little efficacy against Shigella flexneri (95.00 and 92.50% resistance). The percent resistance of Shigella sonnei strains to phosphomycin was elevated (44.69%). All strains studied were sensitive to colimycin and showed little resistance to the combination trimethoprim-sulfamethoxazol (16.42%).

  12. Temperature calibration of fiber optic strain sensor for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Kesavan, K.; Ravisankar, K.; Narayanan, T.; Parivallal, S.; Sreeshylam, P.; Aravindan, P. K.

    2003-10-01

    Major civil engineering structures, such as bridges constitute a significant portion of national wealth, and the cost of maintenance of these structures is very high. Structural health monitoring is a cost effective method of maintenance, and it predicts the structural integrity by early detection of degradation of health of the structure. One of the best ways of structural health monitoring is by the use of fiber optic strain sensors, which are eminently suitable for long term monitoring. However, the apparent strain due to variations in temperature at different measurement times may be very large and has to be accounted for. The apparent strain calibration curves of fiber optic strain sensors bonded to three structural materials, namely, steel, aluminum and concrete are obtained from laboratory experiments which can be used for correcting the temperature induced apparent strain from the total strain measured in the structures.

  13. Electronic origin of strain effects on solute stabilities in iron

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Li, Xiangyan; Xu, Yichun; Liu, C. S.; Liang, Yunfeng

    2016-08-01

    Nonuniform strain fields might induce the segregation of alloying solutes and ultimately lead to the mechanical performance degradation of body-centered-cubic (bcc) Fe based steels serving in extreme environments, which is worthy of investigation. In this paper, two typical volume-conserving strains, shear strain (SS) and normal strain (NS), are proposed to investigate the strain effects on solute stabilities in bcc iron by first-principles calculations. For solutes in each transition metal group, the calculated substitution energy change due to SS exhibits a linear dependence on the valence d radius of the solutes, and the slope decreases in an exponential manner as a function of the absolute difference between the Watson's electronegativity of iron and the averaged value of each transition metal group. This regularity is attributed to the Pauli repulsion between the solutes and the nearest neighboring Fe ions modulated by the hybridization of valence d bands and concluded to be originated from the characteristics of valence d bonding between the transition-metal solutes and Fe ions under SS. For main-group and post transition-metal solutes, the considerable drop of substitution energy change due to NS is concluded to be originated from the low-energy side shift of the widened valence s and p bands of the solutes. Our results indicate that the stabilities of substitutional solutes in iron under volume-conserving strain directly correlate with the intrinsic properties of the alloying elements, such as the valence d radius and occupancy, having or not having valence s and p bands.

  14. Thermomechanical analysis of strain localization in a ductile detachment zone

    NASA Astrophysics Data System (ADS)

    Mulch, A.; Teyssier, C.; Cosca, M. A.; Vennemann, T. W.

    2006-12-01

    At the latitude of the Thor-Odin dome (British Columbia) the Columbia River Detachment defines the eastern margin of the Shuswap metamorphic core complex and localizes in a 1 km thick muscovite-bearing quartzite mylonite. We present a combined 40Ar/39Ar, (micro)structural, and oxygen isotope study of the deformation history in the detachment and evaluate the spatial and temporal relationships between microstructure formation and localization of strain. High-precision 40Ar/39Ar geochronology from different levels in the mylonite delineates a pattern of increasingly younger (49.0 to 47.9 Ma) deformation ages in deeper levels of the mylonitic footwall. The correlation of 40Ar/39Ar ages with decreasing deformation temperatures (˜550°-400°C) in the top 200 m of the mylonite indicates that deformation migrated downward from the contact with the hanging wall. Strain localization was diachronous in progressively deeper levels of the footwall and was likely controlled by fluid-assisted strain hardening due to advective heat removal and contemporaneous reaction weakening due to dissolution-reprecipitation of white mica. The observed constant high-stress microstructures across the entire detachment indicate that flow stress was buffered by the interplay of strain rate and temperature, where high strain rates at elevated temperature produced the same microstructure as lower strain rates under decreasing temperature conditions. The combined data suggest that the complex interplay among temporally nonuniform rates of footwall exhumation, heat advection, and embrittlement by meteoric fluids strongly determines the thermomechanical behavior of extensional detachments.

  15. Strain-Controlled Low-Cycle Fatigue Properties of a Newly Developed Extruded Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Begum, S.; Chen, D. L.; Xu, S.; Luo, Alan A.

    2008-12-01

    To reduce fuel consumption and greenhouse gas emissions, magnesium alloys are being considered for automotive and aerospace applications due to their low density, high specific strength and stiffness, and other attractive traits. Structural applications of magnesium components require low-cycle fatigue (LCF) behavior, since cyclic loading or thermal stresses are often encountered. The aim of this article was to study the cyclic deformation characteristics and evaluate LCF behavior of a recently developed AM30 extruded magnesium alloy. This alloy exhibited a strong cyclic hardening characteristic, with a cyclic strain-hardening exponent of 0.33 compared to the monotonic strain-hardening exponent of 0.15. With increasing total strain amplitude, both plastic strain amplitude and mean stress increased and fatigue life decreased. A significant difference between the tensile and compressive yield stresses occurred, leading to asymmetric hysteresis loops at high strain amplitudes due to twinning in compression and subsequent detwinning in tension. A noticeable change in the modulus was observed due to the pseudoelastic behavior of this alloy. The Coffin-Manson law and Basquin equation could be used to describe the fatigue life. At low strain ratios the alloy showed strong cyclic hardening, which became less significant as the strain ratio increased. The lower the strain ratio, the lower the stress amplitude and mean stress but the higher the plastic strain amplitude, corresponding to a longer fatigue life. Fatigue life also increased with increasing strain rate. Fatigue crack initiation occurred from the specimen surface and crack propagation was mainly characterized by striation-like features. Multiple initiation sites at the specimen surface were observed at higher strain amplitudes.

  16. Flexible and printable paper-based strain sensors for wearable and large-area green electronics

    NASA Astrophysics Data System (ADS)

    Liao, Xinqin; Zhang, Zheng; Liao, Qingliang; Liang, Qijie; Ou, Yang; Xu, Minxuan; Li, Minghua; Zhang, Guangjie; Zhang, Yue

    2016-06-01

    Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control.Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02172g

  17. Strain effects on thermal conductivity of nanostructured silicon by Raman piezothermography

    NASA Astrophysics Data System (ADS)

    Murphy, Kathryn Fay

    A fundamental problem facing the rational design of materials is the independent control of electrical and thermal properties, with implications for a wide range of applications including thermoelectrics, solar thermal power generation, and thermal logic. One strategy for controlling transport involves manipulating the length scales which affect it. For instance, Si thermal conductivity may be reduced with relatively little change in electrical properties when the confining dimension (e.g., nanowire diameter) is small enough that heat carriers are preferentially scattered at free surfaces. However, tailoring properties by geometry or chemistry alone does not allow for on-demand modification, precluding applications which require responsive behavior such as thermal transistors, thermoelectric modules which adapt to their environmental temperature, or switchable thermal barriers. One means of tuning transport is elastic strain, which has long been exploited to improve carrier mobility in electronic devices. Uniform strain is predicted to affect thermal conductivity primarily via changes in heat capacity and phonon velocity, and crystalline defects such as vacancies or dislocations---which induce large strain gradients---should lower thermal conductivity by decreasing the phonon mean free path. Nanowires are ideal for the study of strain and defect effects due to the availability of a range of elastic strain an order of magnitude larger than in bulk and due to their small volumes. However, experimental measurements of strain-mediated thermal conductivity in nanowires have been limited due to the complexity of simultaneously applying and measuring stress or strain, heating, and measuring temperature. In this dissertation, we measure strain effects on thermal conductivity using a novel non-contact approach which we name Raman piezothermography. We apply a uniaxial load to individual Si nanowires, Si thin films, and Si micromeshes under a confocal mu-Raman microscope and

  18. Pathogenic Potential of Saccharomyces Strains Isolated from Dietary Supplements

    PubMed Central

    Monteoliva, Lucía; Querol, Amparo; Molina, María; Fernández-Espinar, María T.

    2014-01-01

    Saccharomyces cerevisiae plays a beneficial role in health because of its intrinsic nutritional value and bio-functional properties, which is why it is also used as a dietary supplement. However, the perception that S. cerevisiae is harmless has changed due to an increasing number of infections caused by this yeast. Given this scenario, we have tested whether viable strains contained in dietary supplements displayed virulence-associated phenotypic traits that could contribute to virulence in humans. We have also performed an in vivo study of the pathogenic potential of these strains using a murine model of systemic infection by intravenous inoculation. A total of 5 strains were isolated from 22 commercial products and tested. Results highlight one strain (D14) in terms of burden levels in brains and kidneys and ability to cause death, whereas the other two strains (D2 and D4) were considered of low virulence. Our results suggest a strong relationship between some of the virulence-associated phenotypic traits (ability to grow at 39°C and pseudohyphal growth) and the in vivo virulence in a mouse model of intravenous inoculation for isolates under study. The isolate displaying greatest virulence (D14) was evaluated in an experimental murine model of gastrointestinal infection with immunosuppression and disruption of mucosal integrity, which are common risk factors for developing infection in humans, and results were compared with an avirulent strain (D23). We showed that D14 was able to spread to mesenteric nodes and distant organs under these conditions. Given the widespread consumption of dietary supplements, we recommend only safe strains be used. PMID:24879417

  19. Strain transfer analysis of optical fiber based sensors embedded in an asphalt pavement structure

    NASA Astrophysics Data System (ADS)

    Wang, Huaping; Xiang, Ping

    2016-07-01

    Asphalt pavement is vulnerable to random damage, such as cracking and rutting, which can be proactively identified by distributed optical fiber sensing technology. However, due to the material nature of optical fibers, a bare fiber is apt to be damaged during the construction process of pavements. Thus, a protective layer is needed for this application. Unfortunately, part of the strain of the host material is absorbed by the protective layer when transferring the strain to the sensing fiber. To account for the strain transfer error, in this paper a theoretical analysis of the strain transfer of a three-layered general model has been carried out by introducing Goodman’s hypothesis to describe the interfacial shear stress relationship. The model considers the viscoelastic behavior of the host material and protective layer. The effects of one crack in the host material and the sensing length on strain transfer relationship are been discussed. To validate the effectiveness of the strain transfer analysis, a flexible asphalt-mastic packaged distributed optical fiber sensor was designed and tested in a laboratory environment to monitor the distributed strain and appearance of cracks in an asphalt concrete beam at two different temperatures. The experimental results indicated that the developed strain transfer formula can significantly reduce the strain transfer error, and that the asphalt-mastic packaged optical fiber sensor can successfully monitor the distributed strain and identify local cracks.

  20. SVAS3: Strain Vector Aided Sensorization of Soft Structures

    PubMed Central

    Culha, Utku; Nurzaman, Surya G.; Clemens, Frank; Iida, Fumiya

    2014-01-01

    Soft material structures exhibit high deformability and conformability which can be useful for many engineering applications such as robots adapting to unstructured and dynamic environments. However, the fact that they have almost infinite degrees of freedom challenges conventional sensory systems and sensorization approaches due to the difficulties in adapting to soft structure deformations. In this paper, we address this challenge by proposing a novel method which designs flexible sensor morphologies to sense soft material deformations by using a functional material called conductive thermoplastic elastomer (CTPE). This model-based design method, called Strain Vector Aided Sensorization of Soft Structures (SVAS3), provides a simulation platform which analyzes soft body deformations and automatically finds suitable locations for CTPE-based strain gauge sensors to gather strain information which best characterizes the deformation. Our chosen sensor material CTPE exhibits a set of unique behaviors in terms of strain length electrical conductivity, elasticity, and shape adaptability, allowing us to flexibly design sensor morphology that can best capture strain distributions in a given soft structure. We evaluate the performance of our approach by both simulated and real-world experiments and discuss the potential and limitations. PMID:25036332

  1. Volumetric Stress-Strain Analysis of Optohydrodynamically Suspended Biological Cells

    PubMed Central

    Liang, Yu; Saha, Asit K.

    2011-01-01

    Ongoing investigations are exploring the biomechanical properties of isolated and suspended biological cells in pursuit of understanding single-cell mechanobiology. An optical tweezer with minimal applied laser power has positioned biologic cells at the geometric center of a microfluidic cross-junction, creating a novel optohydrodynamic trap. The resulting fluid flow environment facilitates unique multiaxial loading of single cells with site-specific normal and shear stresses resulting in a physical albeit extensional state. A recent two-dimensional analysis has explored the cytoskeletal strain response due to these fluid-induced stresses [Wilson and Kohles, 2010, “Two-Dimensional Modeling of Nanomechanical Stresses-Strains in Healthy and Diseased Single-Cells During Microfluidic Manipulation,” J Nanotechnol Eng Med, 1(2), p. 021005]. Results described a microfluidic environment having controlled nanometer and piconewton resolution. In this present study, computational fluid dynamics combined with multiphysics modeling has further characterized the applied fluid stress environment and the solid cellular strain response in three dimensions to accompany experimental cell stimulation. A volumetric stress-strain analysis was applied to representative living cell biomechanical data. The presented normal and shear stress surface maps will guide future microfluidic experiments as well as provide a framework for characterizing cytoskeletal structure influencing the stress to strain response. PMID:21186894

  2. Highly tensile-strained Ge/InAlAs nanocomposites

    PubMed Central

    Jung, Daehwan; Faucher, Joseph; Mukherjee, Samik; Akey, Austin; Ironside, Daniel J.; Cabral, Matthew; Sang, Xiahan; Lebeau, James; Bank, Seth R.; Buonassisi, Tonio; Moutanabbir, Oussama; Lee, Minjoo Larry

    2017-01-01

    Self-assembled nanocomposites have been extensively investigated due to the novel properties that can emerge when multiple material phases are combined. Growth of epitaxial nanocomposites using lattice-mismatched constituents also enables strain-engineering, which can be used to further enhance material properties. Here, we report self-assembled growth of highly tensile-strained Ge/In0.52Al0.48As (InAlAs) nanocomposites by using spontaneous phase separation. Transmission electron microscopy shows a high density of single-crystalline germanium nanostructures coherently embedded in InAlAs without extended defects, and Raman spectroscopy reveals a 3.8% biaxial tensile strain in the germanium nanostructures. We also show that the strain in the germanium nanostructures can be tuned to 5.3% by altering the lattice constant of the matrix material, illustrating the versatility of epitaxial nanocomposites for strain engineering. Photoluminescence and electroluminescence results are then discussed to illustrate the potential for realizing devices based on this nanocomposite material. PMID:28128282

  3. Guiding Spin Spirals by Local Uniaxial Strain Relief

    NASA Astrophysics Data System (ADS)

    Hsu, Pin-Jui; Finco, Aurore; Schmidt, Lorenz; Kubetzka, André; von Bergmann, Kirsten; Wiesendanger, Roland

    2016-01-01

    We report on the influence of uniaxial strain relief on the spin spiral state in the Fe double layer grown on Ir(111). Scanning tunneling microscopy (STM) measurements reveal areas with reconstruction lines resulting from uniaxial strain relief due to the lattice mismatch of Fe and Ir atoms, as well as pseudomorphic strained areas. Magnetic field-dependent spin-polarized STM measurements of the reconstructed Fe double layer reveal cycloidal spin spirals with a period on the nm scale. Globally, the spin spiral wave fronts are guided along symmetry-equivalent [11 2 ¯ ] crystallographic directions of the fcc(111) substrate. On an atomic scale the spin spiral propagation direction is linked to the [001] direction of the bcc(110)-like Fe, leading to a zigzag shaped wave front. The isotropically strained pseudomorphic areas also exhibit a preferred magnetic periodicity on the nm scale but no long-range order. We find that already for local strain relief with a single set of reconstruction lines a strict guiding of the spin spiral is realized.

  4. Time-dependent strains and stresses in a pumpkin balloon

    NASA Astrophysics Data System (ADS)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    This paper presents a study of pumpkin-shaped superpressure balloons consisting of gores made from a thin polymeric film attached to high stiffness meridional tendons This type of design is being used for the NASA ULDB balloons The gore film shows considerable time-dependent stress relaxation whereas the behaviour of the tendons is essentially time-independent Upon inflation and pressurization the instantaneous i e linear-elastic strain and stress distributions in the film show significantly higher values in the meridional direction However over time and due to the biaxial visco-elastic stress relaxation of the the gore material the em hoop strains increase and the em meridional stresses decrease whereas the em remaining strain and stress components remain substantially unchanged These results are important for a correct assessment of the structural integrity of a pumpkin balloon in a long-duration mission both in terms of the material performance and the overall stability of the shape of the balloon An experimental investigation of the time dependence of the biaxial strain distribution in the film of a 4 m diameter 48 gore pumpkin balloon is presented The inflated shape of selected gores has been measured using photogrammetry and the time variation in strain components at some particular points of these gores has been measured under constant pressure and temperature The results show good correlation with a numerical study using the ABAQUS finite-element package that includes a widely used model of

  5. Time-dependent strains and stresses in a pumpkin balloon

    NASA Technical Reports Server (NTRS)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    2006-01-01

    This paper presents a study of pumpkin-shaped superpressure balloons, consisting of gores made from a thin polymeric film attached to high stiffness, meridional tendons. This type of design is being used for the NASA ULDB balloons. The gore film shows considerable time-dependent stress relaxation, whereas the behaviour of the tendons is essentially time-independent. Upon inflation and pressurization, the "instantaneous", i.e. linear-elastic strain and stress distribution in the film show significantly higher values in the meridional direction. However, over time, and due to the biaxial visco-elastic stress relaxation of the the material, the hoop strains increase and the meridional stresses decrease, whereas the remaining strain and stress components remain substantially unchanged. These results are important for a correct assessment of the structural integrity of a pumpkin balloon in a long-duration mission, both in terms of the material performance and the overall stability of the shape of the balloon. An experimental investigation of the time dependence of the biaxial strain distribution in the film of a 4 m diameter, 48 gore pumpkin balloon is presented. The inflated shape of selected gores has been measured using photogrammetry and the time variation in strain components at some particular points of these gores has been measured under constant pressure and temperature. The results show good correlation with a numerical study, using the ABAQUS finite-element package, that includes a widely used model of the visco-elastic response of the gore material:

  6. Tuning nanoparticle structure and surface strain for catalysis optimization.

    PubMed

    Zhang, Sen; Zhang, Xu; Jiang, Guangming; Zhu, Huiyuan; Guo, Shaojun; Su, Dong; Lu, Gang; Sun, Shouheng

    2014-05-28

    Controlling nanoparticle (NP) surface strain, i.e. compression (or stretch) of surface atoms, is an important approach to tune NP surface chemistry and to optimize NP catalysis for chemical reactions. Here we show that surface Pt strain in the core/shell FePt/Pt NPs with Pt in three atomic layers can be rationally tuned via core structural transition from cubic solid solution [denoted as face centered cubic (fcc)] structure to tetragonal intermetallic [denoted as face centered tetragonal (fct)] structure. The high activity observed from the fct-FePt/Pt NPs for oxygen reduction reaction (ORR) is due to the release of the overcompressed Pt strain by the fct-FePt as suggested by quantum mechanics-molecular mechanics (QM-MM) simulations. The Pt strain effect on ORR can be further optimized when Fe in FePt is partially replaced by Cu. As a result, the fct-FeCuPt/Pt NPs become the most efficient catalyst for ORR and are nearly 10 times more active in specific activity than the commercial Pt catalyst. This structure-induced surface strain control opens up a new path to tune and optimize NP catalysis for ORR and many other chemical reactions.

  7. A NEW STRAIN OF TRANSMISSIBLE LEUCEMIA IN FOWLS (STRAIN H).

    PubMed

    Ellermann, V

    1921-03-31

    1. A new strain of fowl leucosis has been transmitted through twelve generations of fowls. 2. An increase in virulence was observed during its passage. This was shown in a shortening of the interval between inoculation and death. The increase in virulence does not affect the number of successful inoculations, which remains approximately constant in from 20 to 40 per cent of the birds employed. 3. As with former strains, the disease manifests itself in various forms; i.e., myeloid and intravascular lymphoid types. A single lymphatic case was observed. 4. In several intravascular cases a diminution in the hemolytic power of the serum was established. This phenomenon was absent in a number of myeloid cases. 5. Active immunization cannot be produced by means of the subcutaneous injection of virulent material. 6. The finding of previous experiments that the virus is filterable has been confirmed. 7. The inoculation of human leucemic material into fowls gave negative results.

  8. Material mechanical characterization method for multiple strains and strain rates

    SciTech Connect

    Erdmand, III, Donald L.; Kunc, Vlastimil; Simunovic, Srdjan; Wang, Yanli

    2016-01-19

    A specimen for measuring a material under multiple strains and strain rates. The specimen including a body having first and second ends and a gage region disposed between the first and second ends, wherein the body has a central, longitudinal axis passing through the first and second ends. The gage region includes a first gage section and a second gage section, wherein the first gage section defines a first cross-sectional area that is defined by a first plane that extends through the first gage section and is perpendicular to the central, longitudinal axis. The second gage section defines a second cross-sectional area that is defined by a second plane that extends through the second gage section and is perpendicular to the central, longitudinal axis and wherein the first cross-sectional area is different in size than the second cross-sectional area.

  9. Sudden death due to pulmonary aspergillosis.

    PubMed

    Bhagavath, Prashantha; Rastogi, Prateek; Menezes, Ritesh G; Valiathan, Manna; Mohan Kumar, T S; Raghavendra Babu, Y P; Kanchan, Tanuj; Monteiro, Francis N P; Nayak, Vinod C

    2009-01-01

    Sudden death due to respiratory pathology is not uncommon and tuberculosis with its complications is well known to cause death. We report a case of a male, train passenger, who started coughing out blood and died on reaching the hospital. Medicolegal autopsy confirmed the sudden unexpected death to be due to pulmonary aspergillosis in the person with past medical history of tuberculosis.

  10. Procedural Due Process Rights in Student Discipline.

    ERIC Educational Resources Information Center

    Pressman, Robert; Weinstein, Susan

    To assist administrators in understanding procedural due process rights in student discipline, this manual draws together hundreds of citations and case summaries of federal and state court decisions and provides detailed commentary as well. Chapter 1 outlines the general principles of procedural due process rights in student discipline, such as…

  11. Due Process in Adverse Personnel Action.

    ERIC Educational Resources Information Center

    Scriven, Michael

    1997-01-01

    A detailed checklist and timeline for ensuring due process are provided for adverse personnel actions, and the need to supplement this with expert, same-jurisdiction legal advice is stressed. This approach emphasizes the importance of treating due process as an ethical as well as a legal requirement. (SLD)

  12. Strains

    MedlinePlus

    Pulled muscle ... can include: Pain and difficulty moving the injured muscle Discolored and bruised skin Swelling ... if you still have pain. Rest the pulled muscle for at least a day. If possible, keep ...

  13. Modelling to very high strains

    NASA Astrophysics Data System (ADS)

    Bons, P. D.; Jessell, M. W.; Griera, A.; Evans, L. A.; Wilson, C. J. L.

    2009-04-01

    Ductile strains in shear zones often reach extreme values, resulting in typical structures, such as winged porphyroclasts and several types of shear bands. The numerical simulation of the development of such structures has so far been inhibited by the low maximum strains that numerical models can normally achieve. Typical numerical models collapse at shear strains in the order of one to three. We have implemented a number of new functionalities in the numerical platform "Elle" (Jessell et al. 2001), which significantly increases the amount of strain that can be achieved and simultaneously reduces boundary effects that become increasingly disturbing at higher strain. Constant remeshing, while maintaining the polygonal phase regions, is the first step to avoid collapse of the finite-element grid required by finite-element solvers, such as Basil (Houseman et al. 2008). The second step is to apply a grain-growth routine to the boundaries of polygons that represent phase regions. This way, the development of sharp angles is avoided. A second advantage is that phase regions may merge or become separated (boudinage). Such topological changes are normally not possible in finite element deformation codes. The third step is the use of wrapping vertical model boundaries, with which optimal and unchanging model boundaries are maintained for the application of stress or velocity boundary conditions. The fourth step is to shift the model by a random amount in the vertical direction every time step. This way, the fixed horizontal boundary conditions are applied to different material points within the model every time step. Disturbing boundary effects are thus averaged out over the whole model and not localised to e.g. top and bottom of the model. Reduction of boundary effects has the additional advantage that model can be smaller and, therefore, numerically more efficient. Owing to the combination of these existing and new functionalities it is now possible to simulate the

  14. Internal-strain effect on the valence band of strained silicon and its correlation with the bond angles

    SciTech Connect

    Inaoka, Takeshi Yanagisawa, Susumu; Kadekawa, Yukihiro

    2014-02-14

    By means of the first-principles density-functional theory, we investigate the effect of relative atom displacement in the crystal unit cell, namely, internal strain on the valence-band dispersion of strained silicon, and find close correlation of this effect with variation in the specific bond angles due to internal strain. We consider the [111] ([110]) band dispersion for (111) ((110)) biaxial tensility and [111] ([110]) uniaxial compression, because remarkably small values of hole effective mass m* can be obtained in this dispersion. Under the practical condition of no normal stress, biaxial tensility (uniaxial compression) involves additional normal compression (tensility) and internal strain. With an increase in the internal-strain parameter, the energy separation between the highest and second-highest valence bands becomes strikingly larger, and the highest band with conspicuously small m* extends remarkably down to a lower energy region, until it intersects or becomes admixed with the second band. This is closely correlated with the change in the specific bond angles, and this change can reasonably explain the above enlargement of the band separation.

  15. Development of the average lattice phase-strain and global elastic macro-strain in Al/TiC composites

    SciTech Connect

    Shi, N.; Bourke, M.A.M.; Goldstone, J.A.; Allison, J.E.

    1994-02-01

    The development of elastic lattice phase strains and global elastic macro-strain in a 15 vol% TiC particle reinforced 2219-T6 Al composite was modeled by finite element method (FEM) as a function of tensile uniaxial loading. The numerical predictions are in excellent agreement with strain measurements at a spallation neutron source. Results from the measurements and modeling indicate that the lattice phase-strains go through a ``zigzag`` increase with the applied load in the direction perpendicular to the load, while the changes of slope in the parallel direction are monotonic. FEM results further showed that it is essential to consider the effect of thermal residual stresses (TRS) in understanding this anomalous behavior. It was demonstrated that, due to TRS, the site of matrix plastic flow initiation changed. On the other hand, the changes of slope of the elastic global macrostrain is solely determined by the phase-stress partition in the composite. An analytical calculation showed that both experimental and numerical slope changes during elastic global strain response under loading could be accurately reproduced by accounting for the changes of phase-stress ratio between the matrix and the matrix.

  16. Cutaneous infections due to Corynebacterium diphtheriae

    PubMed Central

    Cockcroft, W. H.; Boyko, W. J.; Allen, D. E.

    1973-01-01

    Toxigenic Corynebacterium diphtheriae was grown from skin lesions of 44 indigent patients seen at the emergency or out-patient departments of this hospital, 43 of them within the last 16 months of the study period. In all cases staphylococci or hemolytic streptococci were also present in the wounds. An increase in the incidence of clinical diphtheria occurred in the few months preceding and overlapping the period of recognition of the cutaneous infections. The gravis strains, which accounted for the majority of the infections, were sensitive to erythromycin and to penicillin, but were relatively resistant to cloxacillin. PMID:4632361

  17. Genome Sequence of Mannheimia haemolytica Serotype 1 Strain 16041065 BH

    PubMed Central

    Ayalew, Sahlu; Confer, Anthony W.; Hansen, Richard D.

    2017-01-01

    ABSTRACT Here, we report the genome sequence of Mannheimia haemolytica serotype 1 strain 16041065 BH, which was recently isolated from a Midwestern calf that died due to Mannheimia haemolytica–induced pneumonia. This genome comprised a total of 2.7 Mb, with an N50 of 122 kb, and maintained hemolytic activity when grown on blood heart infusion agar supplemented with 5% sheep’s blood. PMID:28385859

  18. Theory of dendritic growth in the presence of lattice strain.

    PubMed

    Pilipenko, D; Brener, E A; Hüter, C

    2008-12-01

    We discuss elastic effects due to lattice strain which are a new key ingredient in the theory of dendritic growth for solid-solid transformations. Both thermal and elastic fields are eliminated by Green's function techniques, and a closed nonlinear integro-differential equation for the evolution of the interface is derived. We find dendritic patterns even without the anisotropy of the surface energy required by classical dendritic growth theory. In this sense, elastic effects serve as a new selection mechanism.

  19. Strain tolerant microfilamentary superconducting wire

    DOEpatents

    Finnemore, Douglas K.; Miller, Theodore A.; Ostenson, Jerome E.; Schwartzkopf, Louis A.; Sanders, Steven C.

    1993-02-23

    A strain tolerant microfilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments.

  20. Virtual strain gage size study

    DOE PAGES

    Reu, Phillip L.

    2015-09-22

    DIC is a non-linear low-pass spatial filtering operation; whether we consider the effect of the subset and shape function, the strain window used in the strain calculation, of other post-processing of the results, each decision will impact the spatial resolution, of the measurement. More fundamentally, the speckle size limits, the spatial resolution by dictating the smallest possible subset. After this decision the processing settings are controlled by the allowable noise level balanced by possible bias errors created by the data filtering. This article describes a process to determine optimum DIC software settings to determine if the peak displacements or strainsmore » are being found.« less

  1. Heroin fatality due to penile injection.

    PubMed

    Winek, C L; Wahba, W W; Rozin, L

    1999-03-01

    Death due to heroin overdose and/or rapid injection of heroin is a frequent occurrence among opioid addicts. We present an unusual case of heroin fatality due to the injection of the drug in the penis. Blood, urine, bile, and vitreous humor concentrations of morphine were 0.68, 0.49, 0.32 and 0.062 microg/ml, respectively. Ethanol was detected at concentrations of 104, 124, 106, and 94 mg/dl in the blood, urine, bile, and vitreous humor, respectively. The cause of death was determined to be due to heroin and ethanol intoxication.

  2. Levofloxacin resistance of Helicobacter pylori strains isolated from patients in southern Poland, between 2006-2012.

    PubMed

    Karczewska, Elzbieta; Klesiewicz, Karolina; Wojtas-Bonior, Izabela; Skiba, Iwona; Sito, Edward; Czajecki, Krzysztof; Zwolińska-Wcisło, Małgorzata; Budak, Alicja

    2014-01-01

    An increasing resistance of Helicobacter pylori (H. pylori) to antimicrobial agents leads to the need of regional monitoring of the prevalence resistant strains (according to the Maastricht/Florence consensus report, 2012). The aim of the study was to assess the resistance to levofloxacin of H. pylori strains isolated from adult patients of Małopolska region in Poland. Bioptates taken from gastric mucosa during gastroscopy constituted the material for the study. Two hundred ten H. pylori strains were isolated from 811 patients. A majority of strains (171) came from patients before the treatment of H. pylori infections while the remaining 39 strains were isolated from patients after the failed therapy. Susceptibility of H. pylori to levofloxacin was determined by strips impregnated with antibiotic gradient (E-test, bioMerieux). The obtained minimum inhibitory concentration (MIC) values ranged from 0.002 mg/L to 32 mg/L. The percentage of strains resistant to levofloxacin amounted to 8.10% (17/210). Among the group of strains isolated from patients before the treatment, 5.85% (10/171) of H. pylori strains were resistant to levofloxacin. In the group of strains isolated from patients after the treatment 17.95% (7/39) of strains were resistant. The difference in the frequency of H. pylori strains resistant to levofloxacin in patients before and after the treatment of the infection due to H. pylori was statistically significant (p = 0.0297). The low percentage of H. pylori strains resistant to levofloxacin justify that the introduction of a triple therapy with levofloxacin is a good alternative in the treatment of H. pylori infections, especially in regions with high prevalence of H. pylori strains resistant to clarithromycin (> 20%).

  3. Strain softening in stretched DNA

    PubMed Central

    Luan, Binquan; Aksimentiev, Aleksei

    2010-01-01

    The microscopic mechanics of DNA stretching was characterized using extensive molecular dynamics simulations. By employing an anisotropic pressure control method, realistic force-extension dependences of effectively infinite DNA molecules were obtained. A coexistence of B- and S-DNA domains was observed during the overstretching transition. The simulations revealed that strain softening may occur in the process of stretching torsionally constrained DNA. The latter observation was qualitatively reconciled with available experimental data using a random-field Ising model. PMID:18851334

  4. High Temperature Capacitive Strain Gage

    NASA Technical Reports Server (NTRS)

    Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

    1990-01-01

    Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

  5. High temperature capacitive strain gage

    NASA Astrophysics Data System (ADS)

    Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

    1990-01-01

    Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

  6. Strain-Detecting Composite Materials

    NASA Technical Reports Server (NTRS)

    Wallace, Terryl A. (Inventor); Smith, Stephen W. (Inventor); Piascik, Robert S. (Inventor); Horne, Michael R. (Inventor); Messick, Peter L. (Inventor); Alexa, Joel A. (Inventor); Glaessgen, Edward H. (Inventor); Hailer, Benjamin T. (Inventor)

    2016-01-01

    A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700.degree. C. to form the composite material.

  7. Long FBG sensor characterization of residual strains in AS4/PPS thermoplastic laminates

    NASA Astrophysics Data System (ADS)

    Sorensen, Larissa K.; Gmur, Thomas; Botsis, John

    2004-07-01

    The consolidation of thermoplastic composites produces internal residual strains due to the differences between the coefficients of thermal expansion of the component materials. In the case of AS4/PPS (carbon fibre-polyphenylene sulphide), where the melting/solidification temperature is 280°C, there exists a 255°C range wherein the various constituents will contract/expand to different degrees. A fibre Bragg grating (FBG) sensor may be embedded into this laminate with the goal of characterizing the residual strains; however, these strains may be non-uniform in the longitudinal and transverse directions, and may also vary depending on the laminate architecture. Non-uniform axial strains typically broaden and split the FBG sensor's spectral response, making it difficult to measure the strain distribution. Also, load-induced birefringence caused by the consolidation process will complicate the interpretation of the spectral response. This research is directed at understanding the residual strain state in FBG sensors due to the fabrication process. It is the aim of this study to experimentally investigate the residual strains in long and short gauge length FBG sensors embedded in the 0° plies of AS4/PPS unidirectional and cross-ply laminates (200 x 50 x 3.6 mm). Long gauge length sensors are monitored throughout the fabrication process, to provide insight into the development of the residual strains.

  8. Cushing syndrome due to adrenal tumor

    MedlinePlus

    ... syndrome. It occurs when a tumor of the adrenal gland releases excess amounts of the hormone cortisol. Causes ... hormone cortisol. This hormone is made in the adrenal glands . Too much cortisol can be due to various ...

  9. [Recurrent intestinal ischemia due to factor VIII].

    PubMed

    Castellanos Monedero, Jesús Javier; Legaz Huidobro, María Luisa; Galindo Andugar, María Angeles; Rodríguez Pérez, Alvaro; Mantrana del Valle, José María

    2008-01-01

    Intestinal ischemia is difficult to diagnose and can be caused by several etiologic processes. We report the case of a female patient with recurrent bowel ischemia due to small vessel thrombosis, which is caused by factor VIII, a procoagulant factor.

  10. Termination of Faculty due to Financial Exigency.

    ERIC Educational Resources Information Center

    Holloway, John P.

    1980-01-01

    Recent court cases involving termination of faculty due to financial exigency are summarized. Sections include an introduction, definition, a survey of recent cases, recommendations, conclusions and questions, and a bibliography. (Author/LC)

  11. Occurrence of pneumomediastinum due to dental procedures.

    PubMed

    Aslaner, Mehmet Ali; Kasap, Gül Nihal; Demir, Cihat; Akkaş, Meltem; Aksu, Nalan M

    2015-01-01

    The occurrence of pneumomediastinum and massive subcutaneous emphysema due to dental procedures is quite rare. We present a case of pneumomediastinum and massive subcutaneous emphysema that occurred during third molar tooth extraction with air-turbine handpiece.

  12. Facial nerve palsy due to birth trauma

    MedlinePlus

    Seventh cranial nerve palsy due to birth trauma; Facial palsy - birth trauma; Facial palsy - neonate; Facial palsy - infant ... infant's facial nerve is also called the seventh cranial nerve. It can be damaged just before or at ...

  13. Detection of Left Ventricular Regional Function in Asymptomatic Children with beta-Thalassemia Major by Longitudinal Strain and Strain Rate Imaging

    PubMed Central

    Bay, Ali; Başpınar, Osman; Leblebisatan, Göksel; Yalçın, Ali Seçkin; İrdem, Ahmet

    2013-01-01

    Objective: Cardiac failure due to iron overload remains the most common cause of death in patients with beta-thalassemia major. This study aimed to evaluate myocardial function in children with beta-thalassemia major using standard echocardiography technique and strain rate imaging. Materials and Methods: Conventional echocardiographic analysis, tissue velocity imaging, and strain/strain rate imaging of the left ventricle were evaluated in 48 children with beta-thalassemia major (19 girls, 29 boys; 8.39±4.05 years) and 22 healthy children (11 girls, 11 boys; 8±3.72 years). Results: Conventional echocardiographic examinations revealed that beta-thalassemia patients had larger left ventricular end-systolic diameter, end-diastolic and end-systolic volume, left ventricular mass index, and mitral early/late diastolic flow velocity ratio (p<0.05). Strain and strain rate imaging study of the basal lateral wall of the left ventricle was higher in patients than in controls, at p=0.035 and p=0.008, respectively. Conclusion: We found that superior systolic strain and strain rate imaging of the left ventricle indicated the presence of regional systolic function in the left ventricular wall. We suggest that left ventricle volume and mass index parameters might be more sensitive than the other conventional and strain/strain rate imaging parameters during childhood. However, the adulthood strain and strain rate imaging values may be lower than controls, exceeding the critical level of iron overload. Conflict of interest:None declared. PMID:24385808

  14. Strains and Sprains Are a Pain

    MedlinePlus

    ... strain at some point. Strains and sprains are common injuries, especially for kids who are very active or ... such as twisting your ankle. This kind of injury is common in sports, but also can happen any time ...

  15. Greenhouse effect due to atmospheric nitrous oxide

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Wang, W. C.; Lacis, A. A.

    1976-01-01

    The greenhouse effect due to nitrous oxide in the present atmosphere is about 0.8 K. Increase in atmospheric N2O due to perturbation of the nitrogen cycle by man may lead to an increase in surface temperature as large as 0.5 K by 2025, or 1.0 K by 2100. Other climatic effects of N2O are briefly discussed.

  16. Strain Monitoring of Flexible Structures

    NASA Technical Reports Server (NTRS)

    Litteken, Douglas A.

    2017-01-01

    , such as tensile testing, fatigue testing, and shear testing, but common measurement techniques cannot be used on fabric. Measuring strain in a material and during a test is a critical parameter for an engineer to monitor the structure during the test and correlate to an analytical model. The ability to measure strain in fabric structures is a challenge for NASA. Foil strain gauges, for example, are commonplace on metallic structures testing, but are extremely difficult to interface with a fabric substrate. New strain measuring techniques need to be developed for use with fabric structures. This paper investigates options for measuring strain in fabric structures for both ground testing and in-space structural health monitoring. It evaluates current commercially available options and outlines development work underway to build custom measurement solutions for NASA's fabric structures.

  17. Turbulent Plane Wakes Subjected to Successive Strains

    NASA Technical Reports Server (NTRS)

    Rogers, Michael M.

    2003-01-01

    Six direct numerical simulations of turbulent time-evolving strained plane wakes have been examined to investigate the response of a wake to successive irrotational plane strains of opposite sign. The orientation of the applied strain field has been selected so that the flow is the time-developing analogue of a spatially developing wake evolving in the presence of either a favourable or an adverse streamwise pressure gradient. The magnitude of the applied strain rate a is constant in time t until the total strain e(sup at) reaches about four. At this point, a new simulation is begun with the sign of the applied strain being reversed (the original simulation is continued as well). When the total strain is reduced back to its original value of one, yet another simulation is begun with the sign of the strain being reversed again back to its original sign. This process is done for both initially "favourable" and initially "adverse" strains, providing simulations for each of these strain types from three different initial conditions. The evolution of the wake mean velocity deficit and width is found to be very similar for all the adversely strained cases, with both measures rapidly achieving exponential growth at the rate associated with the cross-stream expansive strain e(sup at). In the "favourably" strained cases, the wake widths approach a constant and the velocity deficits ultimately decay rapidly as e(sup -2at). Although all three of these cases do exhibit the same asymptotic exponential behaviour, the time required to achieve this is longer for the cases that have been previously adversely strained (by at approx. equals 1). These simulations confirm the generality of the conclusions drawn in Rogers (2002) regarding the response of plane wakes to strain. The evolution of strained wakes is not consistent with the predictions of classical self-similar analysis; a more general equilibrium similarity solution is required to describe the results. At least for the cases

  18. Using BEEM To Probe Strains In Semiconductors

    NASA Technical Reports Server (NTRS)

    Bell, L. Douglas; Milliken, Autumn M.; Manion, Stephen J.; Kaiser, William J.

    1996-01-01

    Ballistic-electron-emission microscopy (BEEM) useful in determining strains in semiconductors under some conditions. More specifically, BEEM is variant of scanning tunneling microscopy and sensitive to electronic structure of probed material. In present approach, BEEM used to obtain data on those aspects of variations in electronic structures related to variations in strains. Then by use of mathematical modeling of relationships between electronic structures and strains, variations in strains deduced from BEEM data.

  19. Temperature-Compensating Inactive Strain Gauge

    NASA Technical Reports Server (NTRS)

    Moore, Thomas C., Sr.

    1993-01-01

    Thermal contribution to output of active gauge canceled. High-temperature strain gauges include both active gauge wires sensing strains and inactive gauge wires providing compensation for thermal contributions to gauge readings. Inactive-gauge approach to temperature compensation applicable to commercially available resistance-type strain gauges operating at temperatures up to 700 degrees F and to developmental strain gauges operating at temperatures up to 2,000 degrees F.

  20. Optical Fibers Would Sense Local Strains

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Proposed fiber-optic transducers measure local strains. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift is sensitive to strain. Phase shifts in single-mode fibers vary with strains. In alternative version, multiple portions of optical fiber sensitive to strains characteristic of specific vibrational mode of object. Same principle also used with two-mode fiber.

  1. Strain Rate Effects on Ultimate Strain of Copper

    DTIC Science & Technology

    1979-05-01

    34Dogbone" Specimen Used for Quasi-Static 5 and Intermediate Rate Tests 2 Schematic of Split Hopkinso’v Bar Apparatus 7 3a PETN Filled Tube Specimen...48 Experiment 25 Calculated Stress Components in Copper Cylinder 52 Expanded by PETN 26 Fracture of Explosively Expanded Cylindrical 54 Tube A-la...Record of Shot No. 10 73 A7b Framing Camera Record of Shot No. 10 74 A-8 Strain Versus Time for Copper Tube Expanded 75 by PETN vi

  2. Haemophilus ducreyi Cutaneous Ulcer Strains Are Nearly Identical to Class I Genital Ulcer Strains

    PubMed Central

    Gangaiah, Dharanesh; Webb, Kristen M.; Humphreys, Tricia L.; Fortney, Kate R.; Toh, Evelyn; Tai, Albert; Katz, Samantha S.; Pillay, Allan; Chen, Cheng-Yen; Roberts, Sally A.; Munson, Robert S.; Spinola, Stanley M.

    2015-01-01

    Background Although cutaneous ulcers (CU) in the tropics is frequently attributed to Treponema pallidum subspecies pertenue, the causative agent of yaws, Haemophilus ducreyi has emerged as a major cause of CU in yaws-endemic regions of the South Pacific islands and Africa. H. ducreyi is generally susceptible to macrolides, but CU strains persist after mass drug administration of azithromycin for yaws or trachoma. H. ducreyi also causes genital ulcers (GU) and was thought to be exclusively transmitted by microabrasions that occur during sex. In human volunteers, the GU strain 35000HP does not infect intact skin; wounds are required to initiate infection. These data led to several questions: Are CU strains a new variant of H. ducreyi or did they evolve from GU strains? Do CU strains contain additional genes that could allow them to infect intact skin? Are CU strains susceptible to azithromycin? Methodology/Principal Findings To address these questions, we performed whole-genome sequencing and antibiotic susceptibility testing of 5 CU strains obtained from Samoa and Vanuatu and 9 archived class I and class II GU strains. Except for single nucleotide polymorphisms, the CU strains were genetically almost identical to the class I strain 35000HP and had no additional genetic content. Phylogenetic analysis showed that class I and class II strains formed two separate clusters and CU strains evolved from class I strains. Class I strains diverged from class II strains ~1.95 million years ago (mya) and CU strains diverged from the class I strain 35000HP ~0.18 mya. CU and GU strains evolved under similar selection pressures. Like 35000HP, the CU strains were highly susceptible to antibiotics, including azithromycin. Conclusions/Significance These data suggest that CU strains are derivatives of class I strains that were not recognized until recently. These findings require confirmation by analysis of CU strains from other regions. PMID:26147869

  3. EDITORIAL: Excelling under strain: band engineering in nanomaterials Excelling under strain: band engineering in nanomaterials

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2013-08-01

    interest in strain studies as well. Researchers in China investigated the effects of tensile strain on the thermal conductivity of graphene nanoribbons. Tuning the thermal conductivity of nanomaterials is highly desirable to optimize their functionality [5]. Wei and colleagues use computer simulations based on reverse nonequilibrium molecular dynamics (RNEMD) to demonstrate what they describe as 'a strain-induced magic flexibility of thermal engineering for carbon-based nanostructures', which may provide a new approach for tailoring nanomaterial functionality. Despite the attractions of more recently discovered carbon nanomaterials silicon remains the bedrock of the semiconductor device industry. Germanium nanostructures also hold significant interest, such as Ge nanowires, which have high mobility and a conveniently low synthesis temperature [6]. In fact the potential applications of germanium nanowires in field effect transistors and nanobridge devices prompted Jagadish and colleagues in Australia, Korea and the UK to investigate the growth of taper-free kinked Ge nanowires in silicon [7]. As they point out many recent reports have highlighted such kinked nanowires as valuable components for novel nanodevices. The work reported by Hrauda and colleagues in this issue looks at the growth of germanium islands on a silicon substrate rather than nanowires [2]. They grow islands on pre-patterned silicon with different levels of Ge deposition with the aim of better understanding how to manage the effects of strain due to lattice mismatch between the two metals. Their results show that considerably more Ge can be deposited without dislocations forming than previously thought and reveal a distinctive cycle of changing island morphologies as Ge is deposited. They add, 'Strain relaxation is revealed to be the main driving force of a rather complex evolution of island shape and Ge distribution'. In reference to his theory of atoms Bohr is once said to have told Werner Heisenberg

  4. An institutional outbreak of Salmonellosis due to lactose-fermenting Salmonella newport.

    PubMed

    Anand, C M; Finlayson, M C; Garson, J Z; Larson, M L

    1980-11-01

    An institutional outbreak of salmonellosis predominantly due to a lactose-fermenting Salmonella newport is described. Control of the outbreak was hampered by delay in the initial recognition of the aberrant strain. On primary culture, salmonellae were detected on bismuth sulfite agar only; colonies that formed on MacConkey agar and Salmonella-Shigella agar could not be differentiated from lactose-fermenting nonpathogenic organisms. The reactions in triple sugar iron were atypical for Salmonella. The lactose-fermenting property was plasmid-mediated and was readily transferable. Phage typing suggested chicken as a possible source of the strain. The need for awareness of the occurrence of such strains of Salmonella that may not be recognized by cultural procedures in common use, the necessity of the routine use of bismuth sulfite agar in procedures for isolation of salmonellae, and the use of lysine iron agar in conjunction with the triple sugar iron agar are emphasized.

  5. Pile Model Tests Using Strain Gauge Technology

    NASA Astrophysics Data System (ADS)

    Krasiński, Adam; Kusio, Tomasz

    2015-09-01

    Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model. To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements: - a linear and stable relationship between measured and physical values, - the force measurement accuracy of about 0.1 kN, - the range of measured forces up to 30 kN, - resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture, - insensitivity to pile bending, - economical factor. These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

  6. Intraplate Deformation Due to Motion of Plates over a Nonspherical Earth

    NASA Astrophysics Data System (ADS)

    Woodworth, D.; Gordon, R. G.

    2015-12-01

    The central tenet of plate tectonics is that the plates are rigid. Not long after the acceptance of plate tectonics, however, it was recognized that the motion of plates over a non-spherical Earth should cause intraplate deformation [McKenzie, 1972; Turcotte & Oxburgh, 1974]. Even so, no firm connection between hypothesized deformation and observed deformation has yet been made. An alternative cause of intraplate deformation is the horizontal contraction of lithosphere as it cools with age [Collette, 1974]. The rate of horizontal thermal contraction decreases as ~1/age and the resulting intraplate deformation should be large enough to cause observed plate circuit non-closures [Kumar & Gordon, 2009]. Strain rates thus obtained for 0 Ma-old, 0.1 Ma-old, 1 Ma-old, and 10 Ma-old oceanic lithosphere respectively are 2 × 10-2 Ma-1 (5 × 10-16 s-1), 8 × 10-3 s-1 (3 × 10-16 s-1), 1.5 × 10-3 Ma-1 (5 × 10-17 s-1), 2 × 10-4 Ma-1 (5 × 10-18 s-1) [Mishra & Gordon, 2015]. Across the Pacific Plate, such strains sum to intraplate relative velocities of up to ≈2 mm yr-1 [Kreemer & Gordon, 2014].Here we attempt to quantify rates of intraplate strain due to motion of plates over a nonspherical Earth to compare with strain rates due to horizontal contraction and due to observed intraplate deformation. We determine rates of northward motion of lithosphere using the SKS-MORVEL set of plate angular velocities relative to the deep mantle [Zheng et al., 2014]. Following Turcotte [1974], we use the approximation of a spherical Earth whose radius of curvature changes with the latitudinal motion of the plate. We considered two end-member cases—no radial strain and no change in thickness—in our calculations. We estimate average strain rates for the twenty-five major plates ranging from ~10-11 to 10-4 Ma-1 (3 × 10-25 to 3 × 10-18 s-1). For the Pacific Plate, we estimate strain rates that approach or exceed those due to thermal contraction only in the oldest lithosphere, where

  7. Disruption of the NADPH-dependent glutamate dehydrogenase affects the morphology of two industrial strains of Penicillium chrysogenum.

    PubMed

    Thykaer, Jette; Rueksomtawin, Kanchana; Noorman, Henk; Nielsen, Jens

    2009-02-23

    New morphological aspects of Penicillium chrysogenum were found during physiological characterisation of two NADPH-dependent glutamate dehydrogenase mutant strains. A morphological characterisation of the previously constructed strains, together with the two beta-lactam producing industrial recipient strains, was conducted. The reference strains showed a compact structure with highly branched hyphal elements whereas the morphology of the DeltagdhA strains consisting of long elongated hyphal elements with few branches. On solid medium, the hyphal growth unit (length) increased from an average of 47 microm tip(-1) in the reference strains to 117 microm tip(-1) in the DeltagdhA strains and in submerged cultures a decrease of 18% in branching frequency was measured due to the gdhA deletion. P. chrysogenum Wis 54-1255, the ancestor of most production strains was also characterised and this strain showed morphology similar to the industrial strains. Interestingly, the constructed strains showed morphology similar to wild type Aspergillus nidulans another species carrying the penicillin biosynthetic cluster. Thus, the results showed that elimination of glutamate dehydrogenase activity in high producing strains of P. chrysogenum has a radical impact on morphology.

  8. Thickness-dependent electronic structure modulation of ferromagnetic films on shape memory alloy substrates based on a pure strain effect

    NASA Astrophysics Data System (ADS)

    Feng, Chun; Hu, Di; Gong, Kui; Jiang, Xumin; Yin, Jianjuan; Cao, Yi; Tang, Xiao-Lei; Yang, Feng; Zhou, Zhongfu; Yu, Guanghua; Andrew Evans, D.

    2016-11-01

    Pure strain-induced electronic structure modulation in ferromagnetic films is critical for developing reliable strain-assisted spintronic devices with low power consumption. For the conventional electricity-controlled strain engineering, it is difficult to reveal the pure strain effect on electronic structure tunability due to the inseparability of pure strain effect and surface charge effect. Here, a non-electrically controlled NiTi shape memory alloy was utilized as a strain output substrate to induce a pure strain on attached Fe films through a thermally controlled shape memory effect. The pure strain induced electronic structure evolution was revealed by in-situ X-ray photoelectron spectroscopy and correlated with first-principles calculations and magnetic anisotropy measurements. A compressive strain enhances the shielding effect for core electrons and significantly tunes their binding energy. Meanwhile, the strain modifies the partial density of states of outer d orbits, which may affect spin-orbit coupling strength and related magnetic anisotropy. This work helps for clarifying the physical nature of the pure strain effect and developing the pure-strain-assisted spintronic devices.

  9. Strain tunable ferroelectric and dielectric properties of BaZrO{sub 3}

    SciTech Connect

    Zhang, Yajun; Liu, Man; Shimada, Takahiro; Kitamura, Takayuki; Wang, Jie

    2014-06-14

    The crucial role of epitaxial (in-plane) strain on the structural, electronic, energetic, ferroelectric, and dielectric properties of BaZrO{sub 3} (BZO) is investigated using density-functional theory calculations. We demonstrate that the BZO crystal subjected to a critical compressive (or tensile) strain exhibits non-trivial spontaneous polarization that is higher than that of well-known ferroelectrics BaTiO{sub 3}, while the BZO crystal is essentially paraelectric in the absence of strain. The electronic structure and Born-effective-charge analyses elucidate that the strain-induced paraelectric-to-ferroelectric transition is driven by the orbital hybridization of d-p electrons between zirconium and oxygen. Through the strain-induced paraelectric-to-ferroelectric phase transition, the dielectric response of BZO is significantly enhanced by the in-plane strain. The tensile strain increases the in-plane dielectric constant by a factor of seven with respect to that without the strain, while the compression tends to enhance the out-of-plane dielectric response. Therefore, strain engineering makes BZO an important electromechanical material due to the diversity in ferroelectric and dielectric properties.

  10. Strain Gated Bilayer Molybdenum Disulfide Field Effect Transistor with Edge Contacts.

    PubMed

    Chai, Yu; Su, Shanshan; Yan, Dong; Ozkan, Mihrimah; Lake, Roger; Ozkan, Cengiz S

    2017-02-10

    Silicon nitride stress capping layer is an industry proven technique for increasing electron mobility and drive currents in n-channel silicon MOSFETs. Herein, the strain induced by silicon nitride is firstly characterized through the changes in photoluminescence and Raman spectra of a bare bilayer MoS2 (Molybdenum disulfide). To make an analogy of the strain-gated silicon MOSFET, strain is exerted to a bilayer MoS2 field effect transistor (FET) through deposition of a silicon nitride stress liner that warps both the gate and the source-drain area. Helium plasma etched MoS2 layers for edge contacts. Current on/off ratio and other performance metrics are measured and compared as the FETs evolve from back-gated, to top-gated and finally, to strain-gated configurations. While the indirect band gap of bilayer MoS2 at 0% strain is 1.25 eV, the band gap decreases as the tensile strain increases on an average of ~100 meV per 1% tensile strain, and the decrease in band gap is mainly due to lowering the conduction band at K point. Comparing top- and strain-gated structures, we find a 58% increase in electron mobility and 46% increase in on-current magnitude, signalling a benign effect of tensile strain on the carrier transport properties of MoS2.

  11. Lactobacillus brevis strains from fermented aloe vera survive gastroduodenal environment and suppress common food borne enteropathogens.

    PubMed

    Kim, Young-Wook; Jeong, Young-Ju; Kim, Ah-Young; Son, Hyun-Hee; Lee, Jong-Am; Jung, Cheong-Hwan; Kim, Chae-Hyun; Kim, Jaeman

    2014-01-01

    Five novel Lactobacillus brevis strains were isolated from naturally fermented Aloe vera leaf flesh. Each strain was identified by Random Amplified Polymorphic DNA (RAPD) analysis and 16S rRNA sequence comparison. These strains were highly tolerant to acid, surviving in pH2.5 for up to 4 hours, and resistant to 5% bile salts at 37°C for 18 hours. Due to its tolerance to acid and bile salts, one strain passed through the gastric barrier and colonised the intestine after oral administration. All five strains inhibited the growth of many harmful enteropathogens without restraining most of normal commensals in the gut and hence named POAL (Probiotics Originating from Aloe Leaf) strains. Additionally, each strain exhibited discriminative resistance to a wide range of antibiotics. The L. brevis POAL strains, moreover, expressed high levels of the glutamate decarboxylase (GAD) gene which produces a beneficial neurotransmitter, γ-aminobutyric acid (GABA). These characteristics in all suggest that the novel L. brevis strains should be considered as potential food additives and resources for pharmaceutical research.

  12. Lactobacillus brevis Strains from Fermented Aloe vera Survive Gastroduodenal Environment and Suppress Common Food Borne Enteropathogens

    PubMed Central

    Kim, Young-Wook; Jeong, Young-Ju; Kim, Ah-Young; Son, Hyun-Hee; Lee, Jong-Am; Jung, Cheong-Hwan; Kim, Chae-Hyun; Kim, Jaeman

    2014-01-01

    Five novel Lactobacillus brevis strains were isolated from naturally fermented Aloe vera leaf flesh. Each strain was identified by Random Amplified Polymorphic DNA (RAPD) analysis and 16S rRNA sequence comparison. These strains were highly tolerant to acid, surviving in pH2.5 for up to 4 hours, and resistant to 5% bile salts at 37°C for 18 hours. Due to its tolerance to acid and bile salts, one strain passed through the gastric barrier and colonised the intestine after oral administration. All five strains inhibited the growth of many harmful enteropathogens without restraining most of normal commensals in the gut and hence named POAL (Probiotics Originating from Aloe Leaf) strains. Additionally, each strain exhibited discriminative resistance to a wide range of antibiotics. The L. brevis POAL strains, moreover, expressed high levels of the glutamate decarboxylase (GAD) gene which produces a beneficial neurotransmitter, γ-aminobutyric acid (GABA). These characteristics in all suggest that the novel L. brevis strains should be considered as potential food additives and resources for pharmaceutical research. PMID:24598940

  13. Strain-specific protective immunity following vaccination against experimental Trypanosoma cruzi infection.

    PubMed

    Haolla, Filipe A; Claser, Carla; de Alencar, Bruna C G; Tzelepis, Fanny; de Vasconcelos, José Ronnie; de Oliveira, Gabriel; Silvério, Jaline C; Machado, Alexandre V; Lannes-Vieira, Joseli; Bruna-Romero, Oscar; Gazzinelli, Ricardo T; dos Santos, Ricardo Ribeiro; Soares, Milena B P; Rodrigues, Mauricio M

    2009-09-18

    Immunisation with Amastigote Surface Protein 2 (asp-2) and trans-sialidase (ts) genes induces protective immunity in highly susceptible A/Sn mice, against infection with parasites of the Y strain of Trypanosoma cruzi. Based on immunological and biological strain variations in T. cruzi parasites, our goal was to validate our vaccination results using different parasite strains. Due to the importance of the CD8(+) T cells in protective immunity, we initially determined which strains expressed the immunodominant H-2K(k)-restricted epitope TEWETGQI. We tested eight strains, four of which elicited immune responses to this epitope (Y, G, Colombian and Colombia). We selected the Colombian and Colombia strains for our studies. A/Sn mice were immunised with different regimens using both T. cruzi genes (asp-2 and ts) simultaneously and subsequently challenged with blood trypomastigotes. Immune responses before the challenge were confirmed by the presence of specific antibodies and peptide-specific T cells. Genetic vaccination did not confer protective immunity against acute infection with a lethal dose of the Colombian strain. In contrast, we observed a drastic reduction in parasitemia and a significant increase in survival, following challenge with an otherwise lethal dose of the Colombia strain. In many surviving animals with late-stage chronic infection, we observed alterations in the heart's electrical conductivity, compared to naive mice. In summary, we concluded that immunity against T. cruzi antigens, similar to viruses and bacteria, may be strain-specific and have a negative impact on vaccine development.

  14. Strain Gated Bilayer Molybdenum Disulfide Field Effect Transistor with Edge Contacts

    NASA Astrophysics Data System (ADS)

    Chai, Yu; Su, Shanshan; Yan, Dong; Ozkan, Mihrimah; Lake, Roger; Ozkan, Cengiz S.

    2017-02-01

    Silicon nitride stress capping layer is an industry proven technique for increasing electron mobility and drive currents in n-channel silicon MOSFETs. Herein, the strain induced by silicon nitride is firstly characterized through the changes in photoluminescence and Raman spectra of a bare bilayer MoS2 (Molybdenum disulfide). To make an analogy of the strain-gated silicon MOSFET, strain is exerted to a bilayer MoS2 field effect transistor (FET) through deposition of a silicon nitride stress liner that warps both the gate and the source-drain area. Helium plasma etched MoS2 layers for edge contacts. Current on/off ratio and other performance metrics are measured and compared as the FETs evolve from back-gated, to top-gated and finally, to strain-gated configurations. While the indirect band gap of bilayer MoS2 at 0% strain is 1.25 eV, the band gap decreases as the tensile strain increases on an average of ~100 meV per 1% tensile strain, and the decrease in band gap is mainly due to lowering the conduction band at K point. Comparing top- and strain-gated structures, we find a 58% increase in electron mobility and 46% increase in on-current magnitude, signalling a benign effect of tensile strain on the carrier transport properties of MoS2.

  15. Strain effects on oxygen vacancy energetics in KTaO3

    DOE PAGES

    Xi, Jianqi; Xu, Haixuan; Zhang, Yanwen; ...

    2017-02-07

    Due to lattice mismatch between epitaxial films and substrates, in-plane strain fields are produced in the thin films, with accompanying structural distortions, and ion implantation can be used to controllably engineer the strain throughout the film. Because of the strain profile, local defect energetics are changed. In this study, the effects of in-plane strain fields on the formation and migration of oxygen vacancies in KTaO3 are investigated using first-principles calculations. In particular, the doubly positive charged oxygen vacancy (V2+O) is studied, which is considered to be the main charge state of the oxygen vacancy in KTaO3. We find that themore » formation energies for oxygen vacancies are sensitive to in-plane strain and oxygen position. The local atomic configuration is identified, and strong relaxation of local defect structure is mainly responsible for the formation characteristics of these oxygen vacancies. Based on the computational results, formation-dependent site preferences for oxygen vacancies are expected to occur under epitaxial strain, which can result in orders of magnitude differences in equilibrium vacancy concentrations on different oxygen sites. In addition, all possible migration pathways, including intra- and inter-plane diffusions, are considered. In contrast to the strain-enhanced intra-plane diffusion, the diffusion in the direction normal to the strained plane is impeded under the epitaxial strain field. Lastly, these anisotropic diffusion processes can further enhance site preferences.« less

  16. Study of Unrecovered Strain and Critical Stresses in One-Way Shape Memory Nitinol

    NASA Astrophysics Data System (ADS)

    Honarvar, Mohammad; Datla, Naresh V.; Konh, Bardia; Podder, Tarun K.; Dicker, Adam P.; Yu, Yan; Hutapea, Parsaoran

    2014-08-01

    Unique thermomechanical properties of Nitinol known as shape memory and superelasticity make it applicable for different fields such as biomedical, structural, and aerospace engineering. These unique properties are due to the comparatively large recoverable strain, which is being produced in a martensitic phase transformation. However, under certain ranges of stresses and temperatures, Nitinol wires exhibit unrecovered strain. For cyclic applications, it is important to understand the strain behavior of Nitinol wires. In this study, the unrecovered strain of different Nitinol wire diameters was investigated using constant stress experiment. Uniaxial tensile test has been also performed to find the range of critical stresses. It was observed that the unrecovered strain produced in the first loading-unloading cycle affects the total strain in the subsequent cycles. Moreover, a critical range of stress was found beyond which the unrecovered strain was negligible while the wires heated up to the range of 70-80°C, depending on the wire diameters. The unrecovered strain of wire diameters of 0.19 mm and less was found to be sensitive to the critical stress. On the other hand, for wire diameters bigger than 0.19 mm this connection between the unrecovered strain and the critical stress was not observed for the same range of heating temperature.

  17. Strain Gated Bilayer Molybdenum Disulfide Field Effect Transistor with Edge Contacts

    PubMed Central

    Chai, Yu; Su, Shanshan; Yan, Dong; Ozkan, Mihrimah; Lake, Roger; Ozkan, Cengiz S.

    2017-01-01

    Silicon nitride stress capping layer is an industry proven technique for increasing electron mobility and drive currents in n-channel silicon MOSFETs. Herein, the strain induced by silicon nitride is firstly characterized through the changes in photoluminescence and Raman spectra of a bare bilayer MoS2 (Molybdenum disulfide). To make an analogy of the strain-gated silicon MOSFET, strain is exerted to a bilayer MoS2 field effect transistor (FET) through deposition of a silicon nitride stress liner that warps both the gate and the source-drain area. Helium plasma etched MoS2 layers for edge contacts. Current on/off ratio and other performance metrics are measured and compared as the FETs evolve from back-gated, to top-gated and finally, to strain-gated configurations. While the indirect band gap of bilayer MoS2 at 0% strain is 1.25 eV, the band gap decreases as the tensile strain increases on an average of ~100 meV per 1% tensile strain, and the decrease in band gap is mainly due to lowering the conduction band at K point. Comparing top- and strain-gated structures, we find a 58% increase in electron mobility and 46% increase in on-current magnitude, signalling a benign effect of tensile strain on the carrier transport properties of MoS2. PMID:28186113

  18. Antigenic differentiation of classical swine fever vaccinal strain PAV-250 from other strains, including field strains from Mexico.

    PubMed

    Mendoza, Susana; Correa-Giron, Pablo; Aguilera, Edgar; Colmenares, Germán; Torres, Oscar; Cruz, Tonatiuh; Romero, Andres; Hernandez-Baumgarten, Eliseo; Ciprián, Abel

    2007-10-10

    Twenty-nine classical swine fever virus (CSFv) strains were grown in the PK15 or SK6 cell lines. Antigenic differentiation studies were performed using monoclonal antibodies (McAbs), produced at Lelystad (CDI-DLO), The Netherlands. The monoclonals which were classified numerically as monoclonals 2-13. Epitope map patterns that resulted from the reactivity with McAbs were found to be unrelated to the pathogenicity of the viruses studied. Antigenic determinants were recognized by McAbs 5 and 8, were not detected in some Mexican strains; however, sites for McAb 6 were absent in all strains. The PAV-250 vaccine strain was recognized by all MAbs, except by MAb 6. Furthermore, the Chinese C-S vaccine strain was found to be very similar to the GPE(-) vaccine. None of the studied Mexican vaccines or field strains was found to be similar to the PAV-250 vaccine strain.

  19. Differences in virulence gene expression between atypical enteropathogenic Escherichia coli strains isolated from diarrheic and healthy ruminants.

    PubMed

    Horcajo, Pilar; Domínguez-Bernal, Gustavo; Carrión, Javier; De La Fuente, Ricardo; Ruiz-Santa-Quiteria, José A; Orden, José A

    2013-04-01

    Differences in the pathogenicity of atypical enteropathogenic Escherichia coli (EPEC) strains may be due, at least partially, to different expression patterns of some virulence genes. To investigate this hypothesis, the virulence gene expression patterns of 6 atypical EPEC strains isolated from healthy and diarrheic ruminants were compared using quantitative real-time reverse transcription polymerase chain reaction after growing the bacteria in culture medium alone or after binding it to HeLa epithelial cells. Some virulence genes in strains from diarrheic animals were upregulated relative to their expression in strains from healthy animals. When bacteria were cultured in the presence of HeLa cells, the ehxA and efa1/lifA genes, previously associated with the production of diarrhea, were expressed at higher levels in strains from diarrheic animals than in strains from healthy animals. Thus, the expression levels of some virulence genes may help determine which atypical EPEC strains cause diarrhea in ruminants.

  20. Differences in virulence gene expression between atypical enteropathogenic Escherichia coli strains isolated from diarrheic and healthy ruminants

    PubMed Central

    Horcajo, Pilar; Domínguez-Bernal, Gustavo; Carrión, Javier; De La Fuente, Ricardo; Ruiz-Santa-Quiteria, José A.; Orden, José A.

    2013-01-01

    Differences in the pathogenicity of atypical enteropathogenic Escherichia coli (EPEC) strains may be due, at least partially, to different expression patterns of some virulence genes. To investigate this hypothesis, the virulence gene expression patterns of 6 atypical EPEC strains isolated from healthy and diarrheic ruminants were compared using quantitative real-time reverse transcription polymerase chain reaction after growing the bacteria in culture medium alone or after binding it to HeLa epithelial cells. Some virulence genes in strains from diarrheic animals were upregulated relative to their expression in strains from healthy animals. When bacteria were cultured in the presence of HeLa cells, the ehxA and efa1/lifA genes, previously associated with the production of diarrhea, were expressed at higher levels in strains from diarrheic animals than in strains from healthy animals. Thus, the expression levels of some virulence genes may help determine which atypical EPEC strains cause diarrhea in ruminants. PMID:24082409

  1. Ab initio study of the strain dependence of thermopower in electron-doped SrTiO3.

    PubMed

    Fumega, Adolfo O; Pardo, Victor

    2017-02-15

    In this paper we explore the different mechanisms that affect the thermopower of a band insulating perovskite (in this case, SrTiO3) when subject to strain (both compressive or tensile). We analyze the high temperature, entropy-dominated limit and the lower temperature, energy-transport regime. We observe that the effect of strain in the high-temperature Seebeck coefficient is small at the concentration levels of interest for thermoelectric applications. However, the effective mass changes substantially with strain, which produces an opposite effect to that of the degeneracy breakups brought about by strain. In particular, we find that the thermopower can be enhanced by applying tensile strain in the adequate regime. We conclude that the detrimental effect of strain in thermopower due to band splitting is a minor effect that will not hamper the optimization of the thermoelectric properties of oxides with t 2g -active bands by applying strain.

  2. Ab initio study of the strain dependence of thermopower in electron-doped SrTiO3

    NASA Astrophysics Data System (ADS)

    Fumega, Adolfo O.; Pardo, Victor

    2017-02-01

    In this paper we explore the different mechanisms that affect the thermopower of a band insulating perovskite (in this case, SrTiO3) when subject to strain (both compressive or tensile). We analyze the high temperature, entropy-dominated limit and the lower temperature, energy-transport regime. We observe that the effect of strain in the high-temperature Seebeck coefficient is small at the concentration levels of interest for thermoelectric applications. However, the effective mass changes substantially with strain, which produces an opposite effect to that of the degeneracy breakups brought about by strain. In particular, we find that the thermopower can be enhanced by applying tensile strain in the adequate regime. We conclude that the detrimental effect of strain in thermopower due to band splitting is a minor effect that will not hamper the optimization of the thermoelectric properties of oxides with t 2g -active bands by applying strain.

  3. [A case of osteomyelitis due to Kingella kingae].

    PubMed

    Kuzumoto, Kei; Kubota, Noriko; Saito, Yoshinobu; Fujioka, Fumio; Yumoto, Kayoko; Hidaka, Eiko; Yoshiyuki, Kawakami

    2013-03-01

    Kingella species including K. kingae are non-motile coccobacilli or short straight rods, and their normal habitats appear to be the upper respiratory and oropharyngeal tracts of humans. In recent years, K. kingae strains have been increasingly recognized as common causes of invasive infections in children at the age of less than 4 years. In Japan, however, invasive K. kingae infections including osteomyelitis have rarely been described. We incidentally encountered isolation of a K. kingae strain from intraoperatively obtained specimens from a previously healthy 44-month-old boy. He first consulted a nearby medical facility and a suspected diagnosis of osteomyelitis was made, after which the patient was then transferred to our Nagano Children's hospital. There was evidence of inflammation in his right calcaneus and toe walking was noted. He was treated with surgical drainage. An isolate grown on sheep blood agar with positive oxidase and negative catalase was biochemically characterized with the ID-Test HN20 (Nissui Pharmaceutical Co., Ltd., Tokyo, Japan) kit system together with genetic examinations involving sequencing the 16S rRNA gene, and the infection was finally identified as K. kingae. The patient was successfully treated with cefotiam (CTM) for the first 7 days followed by the administration of trimethoprim-sulfamethoxazole (ST) for an additional 2 months. The K. kingae isolate was confirmed as a sure causative pathogen by observing that the serum showed high agglutinin titers against the isolate. Accumulation of the case reports in Japan with the isolation of this species is essential for clarifying invasive infections due to K. kingae. Our case report is a noteworthy and useful piece of information.

  4. [Dermatomycoses due to pets and farm animals : neglected infections?].

    PubMed

    Nenoff, P; Handrick, W; Krüger, C; Vissiennon, T; Wichmann, K; Gräser, Y; Tchernev, G

    2012-11-01

    Dermatomycoses due to contact with pets and livestock frequently affect children and young adults. Zoophilic dermatophytes are the main important causative agents. It has long been known that the often high inflammatory dermatophytoses of the skin and the scalp are caused mostly by Microsporum canis. Due to an absence of an obligation for reporting fungal infections of the skin to the Public Health Office in Germany, an unnoticed but significant change in responsible pathogens has occurred. Today an increasing number of infections due to zoophilic strains of Trichophyton interdigitale (formerly Trichophyton mentagrophytes) and Trichophyton species of Arthroderma benhamiae are found. The latter mentioned dermatophyte is the anamorph species of the teleomorph Arthroderma benhamiae, which originally was isolated in the Far East (Japan). Source of infection of these dermatophytes are small rodents, in particular guinea pigs. These animals are bought in pet shops by the parents of those children who later are affected by the fungal infection. The coincidental purchase of the relevant fungal pathogen is not obvious to the parents. As a consequence, highly contagious dermatophytoses occur, often tinea capitis sometimes with kerion formation. Further dermatophytes should be considered as cause of a zoophilic dermatomycosis. Both Trichophyton verrucosum, the cause of the ringworm in cattle, and Trichophyton erinacei following contact to hedgehogs are worthy of note. Yeasts cannot be ignored as cause of dermatomycosis, especially Malassezia pachydermatis, the only non-lipophilic species within the genus Malassezia, which can be transferred from dog to men. Cryptococcus neoformans also comes from animal sources. The mucous yeast occurs in bird's dropping, and it causes both pulmonary and central nervous system infections, but also primary and secondary cutaneous cryptococcosis in immunocompromised patients (HIV/AIDS) as possible consequence after contact to these animals.

  5. Effect of strain and strain rate on residual microstructures in copper

    SciTech Connect

    Stevens, M.F.; Follansbee, P.S.

    1986-01-01

    Several specimens of OFE Cu were deformed in compression to study the resulting microstructures at equivalent levels of threshold stress and strain. Equiaxed, diffuse dislocation cells are more persistent in Cu when tested at strain rates exceeding 10/sup 3/ sec/sup -1/. At quasi-static strain rates, dislocation collapse into more distinct, narrow microbands occurs at lower strain levels.

  6. Residual strain change resulting from stress corrosion in Carrara marble

    NASA Astrophysics Data System (ADS)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2016-04-01

    greater relaxation of extensional strains during the preparatory test, leading to a subsequent increase in compression when the samples were returned to the neutral position prior to our measurement. Thin sections of the notch area help confirm these observations, as a narrow but continuous fracture following grain boundaries is evident in M4 and M2. M5 shows a buildup of extensional strains in the notch tip area due to low loading, though no cracking is evident. These results provide exceptional insight into the physics of fracture propagation under typical real-world conditions. We observe notably different mechanical inter- and intragranular responses to long-term static low loading under either wet or dry conditions, a result which contributes significantly to our ability to evaluate the potential impact of changes in (for example) rainfall distribution, chemistry, and meltwater production on tensile fracture propagation and alpine rock slope stability.

  7. Radiation damage due to electromagnetic showers

    SciTech Connect

    Rakhno, Igor; Mokhov, Nikolai; Striganov, Sergei; /Fermilab

    2008-05-01

    Radiation-induced damage due to atomic displacements is essential to correctly predict the behavior of materials in nuclear reactors and at charged-particle accelerators. Traditionally the damage due to hadrons was of major interest. The recent increased interest in high-energy lepton colliders gave rise to the problem of prediction of radiation damage due to electromagnetic showers in a wide energy range--from a few hundred keV and up to a few hundred GeV. The report describes results of an electron- and positron-induced displacement cross section evaluation. It is based on detailed lepton-nucleus cross sections, realistic nuclear form-factors and a modified Kinchin-Pease damage model. Numerical data on displacement cross sections for various target nuclei is presented.

  8. Angioedema-Urticaria Due to Acitretin.

    PubMed

    Solak, Berna; Metin, Nurcan; Erdem, Mustafa Teoman

    2016-01-01

    Acitretin is a synthetic oral retinoid that has been used for a number of dermatological diseases. Several side effects of acitretin have been reported such as teratogenicity, cheilitis, xerosis, dyslipidemia, and photosensitivity. Many drugs, mainly antibiotics and nonsteroidal anti-inflammatory drugs, can cause angioedema-urticaria. We present the case of angioedema-urticaria due to acitretin, confirmed by oral provocation test, in a 61-year-old man with psoriasis. To the best of our knowledge, only 1 case of angioedema due to oral acitretin has been reported in the literature so far. We report this case to draw attention that acitretin may cause angioedema-urticaria and to inform patients about this risk besides other side effects due to acitretin.

  9. Substantive due process after Gonzales v. Carhart.

    PubMed

    Calabresi, Steven G

    2008-06-01

    This Article begins in Part I with a doctrinal evaluation of the status of Washington v. Glucksberg ten years after that decision was handed down. Discussion begins with consideration of the Roberts Court's recent decision in Gonzales v. Carhart and then turns to the subject of Justice Kennedy's views in particular on substantive due process. In Part II, the Article goes on to consider whether the Glucksberg test for substantive due process decision making is correct in light of the original meaning of the Fourteenth Amendment. The Article concludes in Parts II and III that Glucksberg is right to confine substantive due process rights recognition to recognition only of those rights that are deeply rooted in history and tradition.

  10. Outpatient commitment and procedural due process.

    PubMed

    Player, Candice Teri-Lowe

    2015-01-01

    A large empirical literature on Kendra's Law has assessed the impact of court ordered outpatient treatment on outcomes such as treatment adherence, psychiatric hospitalization, quality of life, and treatment costs. Missing from the empirical literature, however, is a better understanding of procedural due process under Kendra's Law. Procedural due process concerns the safeguards that must be in place when governments deprive persons of their liberties, for example--notice, the right to a hearing and the right to appeal. This article reports the findings from a qualitative study of procedural due process and assisted outpatient treatment hearings under Kendra's Law. Attorneys reported significant barriers to effective advocacy on behalf of their clients. Further, despite the shift from a medical model of civil commitment to a judicial model in the 1970s, by and large judges continue to accord great deference to clinical testimony.

  11. Systemic photosensitivity due to Goji berries.

    PubMed

    Gómez-Bernal, Silvia; Rodríguez-Pazos, Laura; Martínez, Francisco Javier García; Ginarte, Manuel; Rodríguez-Granados, María Teresa; Toribio, Jaime

    2011-10-01

    Systemic photosensitivity due to the intake of plants or herbal compounds is a rare phenomenon. Goji berries are widely used as a well-being and anti-aging remedy. In spite of this, only a few adverse reactions and no cases of photosensitivity have been reported to date. A 53-year-old male consulted due to a pruriginous eruption located on sun-exposed areas of 2 weeks of duration. He had been taking Goji berries and infusions of cat's claw herb for 5 and 3 months, respectively. Minimal erythema dose for UVB (MED-UVB) was diminished when the patient was taking these products, and became normal when they were withdrawn. Photoprovocation tests with Goji berries and cat's claw were performed. MED-UVB decreased after the intake of Goji berries, and was normal with cat's claw. We report the first case of systemic photosensitivity due to Goji berries.

  12. Error quantification in strain mapping methods.

    PubMed

    Guerrero, Elisa; Galindo, Pedro; Yáñez, Andrés; Ben, Teresa; Molina, Sergio I

    2007-10-01

    In this article a method for determining errors of the strain values when applying strain mapping techniques has been devised. This methodology starts with the generation of a thickness/defocus series of simulated high-resolution transmission electron microscopy images of InAsxP1-x/InP heterostructures and the application of geometric phase. To obtain optimal defocusing conditions, a comparison of different defocus values is carried out by the calculation of the strain profile standard deviations among different specimen thicknesses. Finally, based on the analogy of real state strain to a step response, a characterization of strain mapping error near an interface is proposed.

  13. Tests of strain analysis by experimental deformation

    NASA Astrophysics Data System (ADS)

    Borradaile, G. J.; McArthur, J.

    1991-01-01

    The linearisation method and Robin's method of strain analysis of granular materials yield accurate strain estimates for a variety of materials deformed experimentally in pure shear. The breakdown of continuum behaviour at high pore fluid pressures causes the methods to overestimate the strain because they do not take added rigid-body rotation into account. Both methods tolerate some variation in initial shape ratio and some degree of initial preferred orientation at modest strains. Results of tests on polymict sandstone indicate that the lower than average ductility of competent clasts may be balanced against an unfavourable degree of preferred orientation to yield an improved strain estimate.

  14. Radio-Frequency Strain Monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Rogowski, Robert S.; Holben, Milford S., Jr.

    1988-01-01

    Radio-frequency (RF) strain monitor developed to measure lengths of objects. RF waveguide or cable bonded to structure monitored. Propagation of RF signal along waveguide results in phase shift proportional to length of path traveled. Impedance mismatches placed in RF cable at nodes of structure. Records mismatches and detects overall length of line and lengths of intervals between nodes. Used to detect changes in elements of large structure with single cable. Monitor has potential for many applications, including monitoring stability of such large structures as aircraft, bridges, and buildings in Earthquake zones.

  15. Mortality due to lung cancer in Mexico.

    PubMed

    Ruíz-Godoy, L; Rizo Rios, P; Sánchez Cervantes, F; Osornio-Vargas, A; García-Cuellar, C; Meneses García, A

    2007-11-01

    The highest mortality due to cancer worldwide for both genders corresponds to lung cancer (1,179,000 deaths). In Mexico, the crude mortality rate due to lung cancer was of 5.01 per 10(5) inhabitants in 1979. The most important risk factor is smoking. The present study was aimed at analyzing the mortality due to lung cancer in Mexico, assessing data from each of the states constituting the Mexican Republic during the 1998-2004 period. Data were obtained from the National Institute of Statistics, Geography and Informatics (INEGI, for its initials in Spanish) corresponding to deaths due to lung cancer (1998-2004). We estimated the mean annual mortality rate (MAMR) for each of the 32 states of Mexico. We used the "World Population Standard". The MAMR was standardized according to age (ARS) direct method, and the standard error was determined by Poisson's approximation at a 95% confidence interval. To know the excess risk due to mortality, we calculated the standardized mortality ratios (SMRs) of ARS for each federal state, using the national rate as reference. In this period, 397,400 deaths due to malignant neoplasms were recorded, corresponding 45,578 (11.5%) to lung cancer; for men, 31,025 (68.1%) with MAMR of 8.9 and the respective ARS of 13.2 both x10(5) inhabitants. For women, results were 4553 (31.9%) deaths with MAMR of 4.1 and ARS of 5.4 both x10(5) inhabitants. The highest mortality rates due to lung cancer in both genders were observed in the north of Mexico, whereas for women this was observed in the central states. Although smoking is the main risk for lung cancer, there are other factors such as environmental pollution or exposure to toxicants that could be associated to this cancer. The years potentially lost due to lung cancer were 258,550 for men and 133,315 for women, with a total of 391,865 according to histopathology registry neoplasm malignant RHNM (1985-1995). Studies focused on the characterization and measurement of polluting agents would be a

  16. Traumatic Endophthalmitis due to Cellulosimicrobium cellulans

    PubMed Central

    Jaru-ampornpan, Pimkwan; Agarwal, Anita; Midha, Narinder K.; Kim, Stephen J.

    2011-01-01

    Purpose. To report a case of traumatic endophthalmitis due to Cellulosimicrobium cellulans. Design. Case report. Methods. Retrospective chart review. Results. To our knowledge, this is the first report of traumatic endophthalmitis due to C. cellulans, which did not respond to intravitreal antibiotics or repeat vitrectomy and ultimately led to the discovery of an occult intraocular foreign body. Conclusions. C. cellulans is a rare cause of endophthalmitis. Greater awareness of this bacterium in the ophthalmic literature as a cause of endophthalmitis and its association with foreign bodies may allow earlier and more purposeful intervention in future cases. PMID:22606461

  17. Frequency of Adverse Events after Vaccination with Different Vaccinia Strains

    PubMed Central

    Kretzschmar, Mirjam; Wallinga, Jacco; Teunis, Peter; Xing, Shuqin; Mikolajczyk, Rafael

    2006-01-01

    Background Large quantities of smallpox vaccine have been stockpiled to protect entire nations against a possible reintroduction of smallpox. Planning for an appropriate use of these stockpiled vaccines in response to a smallpox outbreak requires a rational assessment of the risks of vaccination-related adverse events, compared to the risk of contracting an infection. Although considerable effort has been made to understand the dynamics of smallpox transmission in modern societies, little attention has been paid to estimating the frequency of adverse events due to smallpox vaccination. Studies exploring the consequences of smallpox vaccination strategies have commonly used a frequency of approximately one death per million vaccinations, which is based on a study of vaccination with the New York City Board of Health (NYCBH) strain of vaccinia virus. However, a multitude of historical studies of smallpox vaccination with other vaccinia strains suggest that there are strain-related differences in the frequency of adverse events after vaccination. Because many countries have stockpiled vaccine based on the Lister strain of vaccinia virus, a quantitative evaluation of the adverse effects of such vaccines is essential for emergency response planning. We conducted a systematic review and statistical analysis of historical data concerning vaccination against smallpox with different strains of vaccinia virus. Methods and Findings We analyzed historical vaccination data extracted from the literature. We extracted data on the frequency of postvaccinal encephalitis and death with respect to vaccinia strain and age of vaccinees. Using a hierarchical Bayesian approach for meta-analysis, we estimated the expected frequencies of postvaccinal encephalitis and death with respect to age at vaccination for smallpox vaccines based on the NYCBH and Lister vaccinia strains. We found large heterogeneity between findings from different studies and a time-period effect that showed

  18. Demonstration test of burner liner strain measurements using resistance strain gages

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Anderson, W. L.

    1984-01-01

    A demonstration test of burner liner strain measurements using resistance strain gages as well as a feasibility test of an optical speckle technique for strain measurement are presented. The strain gage results are reported. Ten Kanthal A-1 wire strain gages were used for low cycle fatigue strain measurements to 950 K and .002 apparent strain on a JT12D burner can in a high pressure (10 atmospheres) burner test. The procedure for use of the strain gages involved extensive precalibration and postcalibration to correct for cooling rate dependence, drift, and temperature effects. Results were repeatable within + or - .0002 to .0006 strain, with best results during fast decels from 950 K. The results agreed with analytical prediction based on an axisymmetric burner model, and results indicated a non-uniform circumferential distribution of axial strain, suggesting temperature streaking.

  19. Strain engineering of graphene: a review

    NASA Astrophysics Data System (ADS)

    Si, Chen; Sun, Zhimei; Liu, Feng

    2016-02-01

    Graphene has intrigued the science community by many unique properties not found in conventional materials. In particular, it is the strongest two-dimensional material ever measured, being able to sustain reversible tensile elastic strain larger than 20%, which yields an interesting possibility to tune the properties of graphene by strain and thus opens a new field called ``straintronics''. In this article, the current progress in the strain engineering of graphene is reviewed. We first summarize the strain effects on the electronic structure and Raman spectra of graphene. We then highlight the electron-phonon coupling greatly enhanced by the biaxial strain and the strong pseudomagnetic field induced by the non-uniform strain with specific distribution. Finally, the potential application of strain-engineering in the self-assembly of foreign atoms on the graphene surface is also discussed. Given the short history of graphene straintronics research, the current progress has been notable, and many further advances in this field are expected.

  20. Monitoring and Controlling of Strain During MOCVD of AlGaN for UV Optoelectronics

    SciTech Connect

    Han, J.; Crawford, M.H.; Shul, R.J.; Hearne, S.J.; Chason, E.; Figiel, J.J.; Banas, M.

    1999-01-14

    The grown-in tensile strain, due to a lattice mismatch between AlGaN and GaN, is responsible for the observed cracking that seriously limits the feasibility of nitride-based ultraviolet (UV) emitters. We report in-situ monitoring of strain/stress during MOCVD of AlGaN based on a wafer-curvature measurement technique. The strain/stress measurement confirms the presence of tensile strain during growth of AlGaN pseudomorphically on a thick GaN layer. Further growth leads to the onset of stress relief through crack generation. We find that the growth of AlGaN directly on low-temperature (LT) GaN or AlN buffer layers results in a reduced and possibly controllable strain.

  1. Highly stretchable and sensitive strain sensor based on silver nanowire-elastomer nanocomposite.

    PubMed

    Amjadi, Morteza; Pichitpajongkit, Aekachan; Lee, Sangjun; Ryu, Seunghwa; Park, Inkyu

    2014-05-27

    The demand for flexible and wearable electronic devices is increasing due to their facile interaction with human body. Flexible, stretchable and wearable sensors can be easily mounted on clothing or directly attached onto the body. Especially, highly stretchable and sensitive strain sensors are needed for the human motion detection. Here, we report highly flexible, stretchable and sensitive strain sensors based on the nanocomposite of silver nanowire (AgNW) network and PDMS elastomer in the form of the sandwich structure (i.e., AgNW thin film embedded between two layers of PDMS). The AgNW network-elastomer nanocomposite based strain sensors show strong piezoresistivity with tunable gauge factors in the ranges of 2 to 14 and a high stretchability up to 70%. We demonstrate the applicability of our high performance strain sensors by fabricating a glove integrated with five strain sensors for the motion detection of fingers and control of an avatar in the virtual environment.

  2. Elastic strains at interfaces in InAs/AlSb multilayer structures for quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Nicolai, J.; Gatel, Ch.; Warot-Fonrose, B.; Teissier, R.; Baranov, A. N.; Magen, C.; Ponchet, A.

    2014-01-01

    InAs/AlSb multilayers similar to those used in quantum cascade lasers have been grown by molecular beam epitaxy on (001) InAs substrates. Elastic strain is investigated by high resolution transmission electron microscopy. Thin interfacial regions with lattice distortions significantly different from the strain of the AlSb layers themselves are revealed from the geometrical phase analysis. Strain profiles are qualitatively compared to the chemical contrast of high angle annular dark field images obtained by scanning transmission electron microscopy. The strain and chemical profiles are correlated with the growth sequences used to form the interfaces. Tensile strained AlAs-like interfaces tend to form predominantly due to the high thermal stability of AlAs. Strongly asymmetric interfaces, AlAs-rich and (Al, In)Sb, respectively, can also be achieved by using appropriate growth sequences.

  3. Elastic strains at interfaces in InAs/AlSb multilayer structures for quantum cascade lasers

    SciTech Connect

    Nicolai, J.; Gatel, Ch.; Warot-Fonrose, B.; Ponchet, A.; Teissier, R.; Baranov, A. N.; Magen, C.

    2014-01-20

    InAs/AlSb multilayers similar to those used in quantum cascade lasers have been grown by molecular beam epitaxy on (001) InAs substrates. Elastic strain is investigated by high resolution transmission electron microscopy. Thin interfacial regions with lattice distortions significantly different from the strain of the AlSb layers themselves are revealed from the geometrical phase analysis. Strain profiles are qualitatively compared to the chemical contrast of high angle annular dark field images obtained by scanning transmission electron microscopy. The strain and chemical profiles are correlated with the growth sequences used to form the interfaces. Tensile strained AlAs-like interfaces tend to form predominantly due to the high thermal stability of AlAs. Strongly asymmetric interfaces, AlAs-rich and (Al, In)Sb, respectively, can also be achieved by using appropriate growth sequences.

  4. Formation of strain-induced quantum dots in gated semiconductor nanostructures

    SciTech Connect

    Thorbeck, Ted; Zimmerman, Neil M.

    2015-08-15

    A long-standing mystery in the field of semiconductor quantum dots (QDs) is: Why are there so many unintentional dots (also known as disorder dots) which are neither expected nor controllable. It is typically assumed that these unintentional dots are due to charged defects, however the frequency and predictability of the location of the unintentional QDs suggests there might be additional mechanisms causing the unintentional QDs besides charged defects. We show that the typical strains in a semiconductor nanostructure from metal gates are large enough to create strain-induced quantum dots. We simulate a commonly used QD device architecture, metal gates on bulk silicon, and show the formation of strain-induced QDs. The strain-induced QD can be eliminated by replacing the metal gates with poly-silicon gates. Thus strain can be as important as electrostatics to QD device operation operation.

  5. Fiber Bragg grating dynamic strain sensor using an adaptive reflective semiconductor optical amplifier source.

    PubMed

    Wei, Heming; Tao, Chuanyi; Zhu, Yinian; Krishnaswamy, Sridhar

    2016-04-01

    In this paper, a reflective semiconductor optical amplifier (RSOA) is configured to demodulate dynamic spectral shifts of a fiber Bragg grating (FBG) dynamic strain sensor. The FBG sensor and the RSOA source form an adaptive fiber cavity laser. As the reflective spectrum of the FBG sensor changes due to dynamic strains, the wavelength of the laser output shifts accordingly, which is subsequently converted into a corresponding phase shift and demodulated by an unbalanced Michelson interferometer. Due to the short transition time of the RSOA, the RSOA-FBG cavity can respond to dynamic strains at high frequencies extending to megahertz. A demodulator using a PID controller is used to compensate for low-frequency drifts induced by temperature and large quasi-static strains. As the sensitivity of the demodulator is a function of the optical path difference and the FBG spectral width, optimal parameters to obtain high sensitivity are presented. Multiplexing to demodulate multiple FBG sensors is also discussed.

  6. Theory of Lattice Strain for Materials Undergoing Plastic Deformation

    NASA Astrophysics Data System (ADS)

    Karato, S.

    2008-12-01

    Radial x-ray diffraction is used to probe physical properties of materials including elastic and plastic properties. The theory used behind such an practice is the one developed by Singh (1993) in which the relation between lattice strain and elastic constants and macroscopic stress is derived. In this theory, the variation of inferred stress with the crystallographic planes, (hkl), is due to the elastic anisotropy. However, recent experimental studies showed that in many cases, the variation of stress with (hkl) far exceeds the value expected from this theory. I have developed a modified theory to rectify this problem with Singh's theory. In Singh's theory, the stress distribution in a polycrystalline material is treated only either unrelaxed or relaxed state. The role of plastic deformation is included only to the extent that plastic flow influences this stress state. Such an assumption corresponds to a Voigt model behavior, which is not an appropriate model at high temperatures where continuing plastic flow occurs with concurrent microscopic equilibrium, elastic deformation. This is a Maxwell model type behavior, and my model provides a stress analysis in a Maxwell material with anisotropic and non-linear power-law rheology. In this theory, the lattice strain corresponding to an imposed macroscopic strain-rate is calculated by three steps: (i) conversion of macroscopic strain-rate to macroscopic stress, (ii) conversion of macroscopic stress to microscopic stress at individual grains, and (iii) calculation of microscopic strain due to microscopic stress. The first step involves anisotropy in macroscopic viscosity that depends on anisotropy in crystal plasticity and lattice-preferred orientation. The second step involves anisotropic crystal plasticity and finally the third step involves elastic crystal anisotropy. In most cases, the influence of LPO is weak and in such a case, the lattice strain depends on (hkl) due to the anisotropy in both elastic and plastic

  7. Fiber Optic Strain Sensor for Planetary Gear Diagnostics

    NASA Technical Reports Server (NTRS)

    Kiddy, Jason S.; Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    This paper presents a new sensing approach for helicopter damage detection in the planetary stage of a helicopter transmission based on a fiber optic strain sensor array. Complete helicopter transmission damage detection has proven itself a difficult task due to the complex geometry of the planetary reduction stage. The crowded and complex nature of the gearbox interior does not allow for attachment of sensors within the rotating frame. Hence, traditional vibration-based diagnostics are instead based on measurements from externally mounted sensors, typically accelerometers, fixed to the gearbox exterior. However, this type of sensor is susceptible to a number of external disturbances that can corrupt the data, leading to false positives or missed detection of potentially catastrophic faults. Fiber optic strain sensors represent an appealing alternative to the accelerometer. Their small size and multiplexibility allows for potentially greater sensing resolution and accuracy, as well as redundancy, when employed as an array of sensors. The work presented in this paper is focused on the detection of gear damage in the planetary stage of a helicopter transmission using a fiber optic strain sensor band. The sensor band includes an array of 13 strain sensors, and is mounted on the ring gear of a Bell Helicopter OH-58C transmission. Data collected from the sensor array is compared to accelerometer data, and the damage detection results are presented

  8. Strain-specific Fibril Propagation by an Aβ Dodecamer

    NASA Astrophysics Data System (ADS)

    Dean, Dexter N.; Das, Pradipta K.; Rana, Pratip; Burg, Franklin; Levites, Yona; Morgan, Sarah E.; Ghosh, Preetam; Rangachari, Vijayaraghavan

    2017-01-01

    Low molecular weight oligomers of amyloid-β (Aβ) have emerged as the primary toxic agents in the etiology of Alzheimer disease (AD). Polymorphism observed within the aggregation end products of fibrils are known to arise due to microstructural differences among the oligomers. Diversity in aggregate morphology correlates with the differences in AD, cementing the idea that conformational strains of oligomers could be significant in phenotypic outcomes. Therefore, it is imperative to determine the ability of strains to faithfully propagate their structure. Here we report fibril propagation of an Aβ42 dodecamer called large fatty acid-derived oligomers (LFAOs). The LFAO oligomeric strain selectively induces acute cerebral amyloid angiopathy (CAA) in neonatally-injected transgenic CRND8 mice. Propagation in-vitro occurs as a three-step process involving the association of LFAO units. LFAO-seeded fibrils possess distinct morphology made of repeating LFAO units that could be regenerated upon sonication. Overall, these data bring forth an important mechanistic perspective into strain-specific propagation of oligomers that has remained elusive thus far.

  9. Strain induced novel quantum magnetotransport properties of topological insulators

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Zhang, Shengli; Liu, Daqing

    2016-12-01

    Recent theoretical and experimental researches have revealed that the strained bulk HgTe can be regarded as a three-dimensional topological insulator (TI). Motivated by this, we explore the strain effects on the transport properties of the HgTe surface states, which are modulated by a weak 1D in-plane electrostatic periodic potential in the presence of a perpendicular magnetic field. We analytically derive the zero frequency (dc) diffusion conductivity for the case of quasielastic scattering in the Kubo formalism, and find that, in strong magnetic field regime, the Shubnikov-de Haas oscillations are superimposed on top of the Weiss oscillations due to the electric modulation for null and finite strain. Furthermore, the strain is shown to remove the degeneracy in inversion symmetric Dirac cones on the top and bottom surfaces. This accordingly gives rise to the splitting and mixture of Landau levels, and the asymmetric spectrum of the dc conductivity. These phenomena, not known in a conventional 2D electron gas and even in a strainless TI and graphene, are a consequence of the anomalous spectrum of surface states in a fully stained TI. These results should be valuable for electronic and spintronic applications of TIs, and thus we fully expect to see them in the further experiment.

  10. The plane strain tests in the PROMETRA program

    NASA Astrophysics Data System (ADS)

    Cazalis, B.; Desquines, J.; Carassou, S.; Le Jolu, T.; Bernaudat, C.

    2016-04-01

    A fuel cladding mechanical test, performed under conditions of plane strain deformation in the transverse direction of tube axis, was originally developed at Pennsylvania State University. It was decided to implement this original test within the PROMETRA program using the same experimental procedure and its optimization for a ring mechanical testing on plane strain conditions (PST tests) in hot cells laboratory. This paper presents a detailed description and an interpretation of the Plane Strain Tensile (PST) tests performed in the framework of the PROMETRA program on fresh and irradiated claddings. At first, the context of the PST tests is situated and the specificities of these tests implemented at CEA are justified. Indeed, a significant adjustment of the original experimental procedure is carried out in order to test the irradiated fuel cladding in the best possible conditions. Then, the tests results on fresh Zircaloy-4 and on irradiated Zircaloy-4, M5™ and ZIRLO® specimens are gathered. The main analyses in support of these tests, such as metallographies, fractographic examinations and finite element simulations are detailed. Finally, a synthesis of the interpretation of the tests is proposed. The PST test seems only representative of plane strain fracture conditions when the test material is very ductile (fresh or high temperature or low hydride material like M5TM). However, it provides a relevant representation of the RIA rupture initiation which is observed in irradiated cladding resulting from hydride rim damage due to the strong irradiation of a fuel rod.

  11. Separation of similar yeast strains by IEF techniques.

    PubMed

    Horká, Marie; Růzicka, Filip; Holá, Veronika; Slais, Karel

    2009-06-01

    Rapid and reliable identification of the etiological agents of infectious diseases, especially species that are hardly distinguishable by routinely used laboratory methods, e.g. Candida albicans from C. dubliniensis, is necessary for early administration of an appropriate therapy. Similarly, the differentiation between biofilm-positive and biofilm-negative yeast strains is necessary for the choice of a therapeutic strategy due to higher resistance of the biofilm-positive strains to antifungals. In this study rapid separation and identification of similar strains of Candida, cells and/or their lysates, based on IEF are outlined. The isoelectric points of the monitored "similar pairs" of Candidas, C. albicans and C. dubliniensis and the biofilm-positive C. parapsilosis, C. tropicalis and their biofilm-negative strains were determined by CIEF with UV detection in the acidic pH gradient. The differences between their isoelectric points were up to 0.3 units of pI. Simultaneously, a fast and a simple technique was developed for the lysis of the outer membrane cell and characteristic fingerprints were found in lysate electrophoreograms and in gels from the capillary or the gel IEF, respectively.

  12. Rapid genome resequencing of an atoxigenic strain of Aspergillus carbonarius

    DOE PAGES

    Cabañes, F. Javier; Sanseverino, Walter; Castellá, Gemma; ...

    2015-03-13

    In microorganisms, Ion Torrent sequencing technology has been proved to be useful in whole-genome sequencing of bacterial genomes (5 Mbp). In our study, for the first time we used this technology to perform a resequencing approach in a whole fungal genome (36 Mbp), a non-ochratoxin A producing strain of Aspergillus carbonarius. Ochratoxin A (OTA) is a potent nephrotoxin which is found mainly in cereals and their products, but it also occurs in a variety of common foods and beverages. Due to the fact that this strain does not produce OTA, we focused some of the bioinformatics analyses in genes involvedmore » in OTA biosynthesis, using a reference genome of an OTA producing strain of the same species. This study revealed that in the atoxigenic strain there is a high accumulation of nonsense and missense mutations in several genes. Importantly, a two fold increase in gene mutation ratio was observed in PKS and NRPS encoding genes which are suggested to be involved in OTA biosynthesis.« less

  13. Substrate specificity of the neuraminidase of different mumps virus strains.

    PubMed

    Klamm, H; Pollex, G

    1984-11-01

    The hydrolysis of neuraminlactose, fetuin, ovomucoid, kappa-caseinglycopeptide and mucine from the bovine submaxillary gland with the neuraminidase (NA) of mumps virus strains Jeryl Lynn, Enders and Berlin 9/76 was investigated to determine the pH-dependence of the reaction with the different substrates. The corresponding curves showed splitting into several peaks with reaction maxima ranging from pH 4.7 to pH 6.7. This occurred probably due to the heterogeneity of the virus samples. The NA of each virus strain had the best reaction affinity to neuraminlactose followed by decreasing affinities to ovomucoid, fetuin and kappa-caseinglycopeptide. The mucine from bovine submaxillary gland was not digested at all. The highest hydrolysis of each substrate was found with the Jeryl Lynn strain, which also possessed the lowest substrate specificity. It was followed by that of strain Enders and finally by isolate Berlin 9/76 which, in turn, had the highest substrate specificity. The lower substrate specificity of mumps virus NA seemed to correlate with a lower degree of its cytopathogenicity for hamster ependyma cells.

  14. Spherical nanoindentation stress-strain analysis, Version 1

    SciTech Connect

    Weaver, Jordan S.; Turner, David; Miller, Calvin; Fast, Tony; Al-Harbi, Hamad; Vachhani, Shraddha; Kalidindi, Surya R.

    2016-11-07

    Nanoindentation is a tool that allows the mechanical response of a variety of materials at the nano to micron length scale to be measured. Recent advances in spherical nanoindentation techniques have allowed for a more reliable and meaningful characterization of the mechanical response from nanoindentation experiments in the form on an indentation stress-strain curve. This code base, Spin, is written in MATLAB (The Mathworks, Inc.) and based on the analysis protocols developed by S.R. Kalidindi and S. Pathak [1, 2]. The inputs include the displacement, load, harmonic contact stiffness, harmonic displacement, and harmonic load from spherical nanoindentation tests in the form of an Excel (Microsoft) spreadsheet. The outputs include indentation stress-strain curves and indentation properties as well their variance due to the uncertainty of the zero-point correction in the form of MATLAB data (.mat) and figures (.png). [1] S. Pathak, S.R. Kalidindi. Spherical nanoindentation stress–strain curves, Mater. Sci. Eng R-Rep 91 (2015). [2] S.R. Kalidindi, S. Pathak. Determination of the effective zero-point and the extraction of spherical nanoindentation stress-strain curves, Acta Materialia 56 (2008) 3523-3532.

  15. Wolbachia strains for disease control: ecological and evolutionary considerations

    PubMed Central

    Hoffmann, Ary A; Ross, Perran A; Rašić, Gordana

    2015-01-01

    Wolbachia are endosymbionts found in many insects with the potential to suppress vectorborne diseases, particularly through interfering with pathogen transmission. Wolbachia strains are highly variable in their effects on hosts, raising the issue of which attributes should be selected to ensure that the best strains are developed for disease control. This depends on their ability to suppress viral transmission, invade host populations, persist without loss of viral suppression and not interfere with other control strategies. The potential to achieve these objectives is likely to involve evolutionary constraints; viral suppression may be limited by the ability of infections to spread due to deleterious host fitness effects. However, there are exceptions to these patterns in both natural infections and in novel associations generated following interspecific transfer, suggesting that pathogen blockage, deleterious fitness effects and changes to reproductive biology might be at least partly decoupled to achieve ideal infection attributes. The stability of introduced Wolbachia and its effects on viral transmission remain unclear, but rapid evolutionary changes seem unlikely. Although deliberate transfers of Wolbachia across species remain particularly challenging, the availability of strains with desirable attributes should be expanded, taking advantage of the diversity available across thousands of strains in natural populations. PMID:26366194

  16. Antifungal activity of two Lactobacillus strains with potential probiotic properties.

    PubMed

    Gerbaldo, Gisela A; Barberis, Carla; Pascual, Liliana; Dalcero, Ana; Barberis, Lucila

    2012-07-01

    Aflatoxin (highly toxic and carcinogenic secondary metabolites produced by fungi) contamination is a serious problem worldwide. Modern agriculture and animal production systems need to use high-quality and mycotoxin-free feedstuffs. The use of microorganisms to preserve food has gained importance in recent years due to the demand for reduced use of chemical preservatives by consumers. Lactic acid bacteria are known to produce various antimicrobial compounds that are considered to be important in the biopreservation of food and feed. Lactobacillus rhamnosus L60 and Lactobacillus fermentum L23 are producers of secondary metabolites, such as organic acids, bacteriocins and, in the case of L60, hydrogen peroxide. The antifungal activity of lactobacilli strains was determined by coculture with Aspergillus section Flavi strains by two qualitative and one quantitative methods. Both L23 and L60 completely inhibited the fungal growth of all aflatoxicogenic strains assayed. Aflatoxin B (1) production was reduced 95.7-99.8% with L60 and 27.5-100% with L23. Statistical analysis of the data revealed the influence of L60 and L23 on growth parameters and aflatoxin B (1) production. These results are important given that these aflatoxicogenic fungi are natural contaminants of feed used for animal production, and could be effectively controlled by Lactobacillus L60 and L23 strains with probiotic properties.

  17. Strain Sensitivity in Single Walled Carbon Nanotubes for Multifunctional Materials

    NASA Technical Reports Server (NTRS)

    Heath, D. M. (Technical Monitor); Smits, Jan M., VI

    2005-01-01

    Single walled carbon nanotubes represent the future of structural aerospace vehicle systems due to their unparalleled strength characteristics and demonstrated multifunctionality. This multifunctionality rises from the CNT's unique capabilities for both metallic and semiconducting electron transport, electron spin polarizability, and band gap modulation under strain. By incorporating the use of electric field alignment and various lithography techniques, a single wall carbon nanotube (SWNT) test bed for measurement of conductivity/strain relationships has been developed. Nanotubes are deposited at specified locations through dielectrophoresis. The circuit is designed such that the central, current carrying section of the nanotube is exposed to enable atomic force microscopy and manipulation in situ while the transport properties of the junction are monitored. By applying this methodology to sensor development a flexible single wall carbon nanotube (SWNT) based strain sensitive device has been developed. Studies of tensile testing of the flexible SWNT device vs conductivity are also presented, demonstrating the feasibility of using single walled HiPCO (high-pressure carbon monoxide) carbon nanotubes as strain sensing agents in a multi-functional materials system.

  18. Strain-specific Fibril Propagation by an Aβ Dodecamer

    PubMed Central

    Dean, Dexter N.; Das, Pradipta K.; Rana, Pratip; Burg, Franklin; Levites, Yona; Morgan, Sarah E.; Ghosh, Preetam; Rangachari, Vijayaraghavan

    2017-01-01

    Low molecular weight oligomers of amyloid-β (Aβ) have emerged as the primary toxic agents in the etiology of Alzheimer disease (AD). Polymorphism observed within the aggregation end products of fibrils are known to arise due to microstructural differences among the oligomers. Diversity in aggregate morphology correlates with the differences in AD, cementing the idea that conformational strains of oligomers could be significant in phenotypic outcomes. Therefore, it is imperative to determine the ability of strains to faithfully propagate their structure. Here we report fibril propagation of an Aβ42 dodecamer called large fatty acid-derived oligomers (LFAOs). The LFAO oligomeric strain selectively induces acute cerebral amyloid angiopathy (CAA) in neonatally-injected transgenic CRND8 mice. Propagation in-vitro occurs as a three-step process involving the association of LFAO units. LFAO-seeded fibrils possess distinct morphology made of repeating LFAO units that could be regenerated upon sonication. Overall, these data bring forth an important mechanistic perspective into strain-specific propagation of oligomers that has remained elusive thus far. PMID:28098204

  19. Correlation between strain and defects in Bi implanted Si

    NASA Astrophysics Data System (ADS)

    Palade, C.; Lepadatu, A.-M.; Slav, A.; Ciurea, M. L.; Lazanu, S.

    2016-06-01

    The strain in Si containing group-V impurities is a topical subject of study due to its potential applications in quantum computing. In this paper we study 209Bi implanted Si concerning the correlation between the strain produced by stopped Bi ions and trapping characteristics of the defects resulted from implantation. The depths distributions of stopped ions and primary defects are simulated and the distributions of permanent defects are modelled for Si implanted with low fluence 209Bi ions of 28 MeV kinetic energy. For comparison, these depths distributions were similarly calculated for 127I ions with the same fluence and energy, implanted in Si. The results are compared with each other and correlated with the characteristics of traps in these systems, previously obtained. We demonstrate that the intensity of the strain field is the most important factor in changing of trap parameters, while the superposition between the region with strain and the region where defects are located is a second order effect.

  20. Duodenocolic fistula due to safety pin ingestion.

    PubMed

    Cay, Ali; Imamoğlu, Mustafa; Sarihan, Haluk; Sayil, Ozgür

    2004-01-01

    The authors describe the case of a 16-month-old boy with benign duodenocolic fistula due to safety pin ingestion who presented with abdominal pain, diarrhea and weight loss. Etiology, symptomatology, diagnosis and management are discussed and the literature is reviewed. Early diagnosis and surgical management are necessary to avoid serious morbidity.

  1. Bacterial endocarditis due to Kingella kingae.

    PubMed

    Sage, M J; Maslowski, A H; MacCulloch, D

    1983-10-26

    A case of infective bacterial endocarditis due to Kingella kingae in a 26 year old male involving a prosthetic mitral valve is described. Microbiological features of this organism are outlined, and the treatment of this endocarditis is discussed with reference to the four previously reported cases.

  2. Constructing the Uncertainty of Due Dates

    PubMed Central

    Vos, Sarah C.; Anthony, Kathryn E.; O'Hair, H. Dan

    2015-01-01

    By its nature, the date that a baby is predicted to be born, or the due date, is uncertain. How women construct the uncertainty of their due dates may have implications for when and how women give birth. In the United States as many as 15% of births occur before 39 weeks because of elective inductions or cesarean sections, putting these babies at risk for increased medical problems after birth and later in life. This qualitative study employs a grounded theory approach to understand the decisions women make of how and when to give birth. Thirty-three women who were pregnant or had given birth within the past two years participated in key informant or small group interviews. The results suggest that women interpret the uncertainty of their due dates as a reason to wait on birth and as a reason to start the process early; however, information about a baby's brain development in the final weeks of pregnancy may persuade women to remain pregnant longer. The uncertainties of due dates are analyzed using Babrow's problematic integration, which distinguishes between epistemological and ontological uncertainty. The results point to a third type uncertainty, axiological uncertainty. Axiological uncertainty is rooted in the values and ethics of outcomes. PMID:24266788

  3. Fetal anaemia due to pyruvate kinase deficiency.

    PubMed Central

    Gilsanz, F; Vega, M A; Gómez-Castillo, E; Ruiz-Balda, J A; Omeñaca, F

    1993-01-01

    Pyruvate kinase deficiency was diagnosed in an infant by umbilical vessel sampling at 30 weeks' gestation. Although three previous hydropic siblings had been stillborn or died in the neonatal period, this infant survived with transfusion dependent haemolytic anaemia. Prompt fetal diagnosis of pyruvate kinase deficiency is feasible and allows better management of hydrops fetalis due to this disorder. PMID:8285758

  4. Contact dermatitis due to Alstroemeria (Peruvian lily).

    PubMed

    Apted, J H

    1990-01-01

    Two cases of hand dermatitis due to contact with the plant Alstroemeria (Peruvian Lily) are recorded. This plant has been increasingly used for making floral decorations during the last decade. As it is available throughout the year in Victoria more cases are likely to be discovered in the community.

  5. Rectal bezoars due to pumpkin seeds.

    PubMed

    Mirza, Mohammad Salman; Al-Wahibi, Khalifa; Baloch, Shafiq; Al-Qadhi, Hani

    2009-01-01

    Rectal bezoars commonly occur due to seeds, especially in children living in countries south of the Mediterranean and in the Middle-East. Dried seeds are considered a delicacy and consumed widely. Inadequate chewing or hastily eating without removing the hull may lead to their impaction as bezoars, which may require manual removal under general anaesthesia.

  6. Case report. Onychomycosis due to Microsporum canis.

    PubMed

    Romano, C; Paccagnini, E; Pelliccia, L

    2001-05-01

    A case of distal subungual onychomycosis of the big toe due to Microsporum canis is reported in a 69-year-old male asthma patient who had been treated with systemic corticosteroids for the last 3 years. The nail infection was contracted from a cat who was a healthy carrier. The patient was treated successfully with intermittent itraconazole therapy.

  7. What to Expect After Your Due Date

    MedlinePlus

    ... baby is not born by the due date, tests can help the health care provider check on the baby’s health. Some tests, ... your baby move. Others are done in the health care provider’s office or in the hospital. These tests involve electronic fetal monitoring and include the nonstress ...

  8. The Enlightenment and Due Process of Law.

    ERIC Educational Resources Information Center

    Nettleship, Lois

    The purpose of this module for college students is to describe the economic, social, intellectual, and political changes which took place during the Enlightenment period and to show the interrelationship between these changes and concepts behind due process of law. This resource contains an introduction to the module; a list of objectives for the…

  9. Plagiarism Due to Misunderstanding: Online Instructor Perceptions

    ERIC Educational Resources Information Center

    Greenberger, Scott; Holbeck, Rick; Steele, John; Dyer, Thomas

    2016-01-01

    Plagiarism is an ongoing problem in higher education. This problem exists in both online and face-to-face modalities. The literature indicates that there are three ways higher education institutions define plagiarism, which includes theft, deception, and misunderstanding. Plagiarism due to misunderstanding has received less attention in the…

  10. Human Infections Due to Mycobacterium lentiflavum

    PubMed Central

    Tortoli, Enrico; Bartoloni, Alessandro; Erba, Maria Luigia; Levrè, Egle; Lombardi, Natalia; Mantella, Antonia; Mecocci, Lorenzo

    2002-01-01

    Three cases of human disease due to Mycobacterium lentiflavum are reported. In the first, the mycobacterium was responsible for chronic pulmonary disease in an elderly woman; in the second, it gave rise to cervical lymphadenitis in a child; and in the third, it caused a liver abscess in a young AIDS patient. PMID:11826009

  11. AFT Chief Promises Due-Process Reform

    ERIC Educational Resources Information Center

    Sawchuk, Stephen

    2010-01-01

    The president of the American Federation of Teachers (AFT), Randi Weingarten, is putting the sensitive issue of due process on the education reform table, with a pledge to work with districts to streamline the often-cumbersome procedures for dismissing teachers who fail to improve their performance after receiving help and support. She has also…

  12. Due Process Rights in Student Disciplinary Matters.

    ERIC Educational Resources Information Center

    Swem, Lisa L.

    1987-01-01

    Universities must walk a fine line between competing interests in student disciplinary matters. Courts accord differing levels of procedural protection to the student depending on the dispute's nature. While case law shows that a notice, hearing, and substantive evidence are required, due process does not have to meet criminal law standards. (MSE)

  13. Light incoherence due to background space fluctuations

    NASA Astrophysics Data System (ADS)

    Maziashvili, Michael

    2016-12-01

    Working by analogy, we use the description of light fluctuations due to random collisions of the radiating atoms to figure out why the reduction of the coherence for light propagating a cosmological distance in the fluctuating background space is negligibly small to be observed by the stellar interferometry.

  14. Hair transplantation in alopecia due to radiation

    SciTech Connect

    Nordstroem, R.E.; Holsti, L.R.

    1983-10-01

    Two cases of alopecia due to radiation of the scalp are presented in which it has been possible to achieve a technically and cosmetically satisfactory reconstruction by punch hair grafting. This does not mean that every case is suitable, but it does mean that those without contraindications should at least be given a try.

  15. Thoracic empyema due to migrated gallstones.

    PubMed

    Flores-Franco, René Agustín

    2013-01-01

    Hepatobiliary conditions should be considered in the differential diagnosis of right pleural effusion. Here we present the illustrative images of thoracic empyema due to migrated gallstones in a woman who was treated for laparoscopic cholecystectomy one year before. The gallstones were obtained unexpectedly during a thoracentesis with aid of an Abrams needle. This rare complication is discussed under current literature review.

  16. [Cutaneous abscess due to Gemella morbillorum].

    PubMed

    Villamil, Iago; Villar, Alberto; Masa, Luis A

    2009-10-01

    We report a cutaneous abscess due to Gemella morbillorum, a Gram positive coccus found in oropharyngeal flora, that rarely causes disease in humans. Infections associated to this agent are similar to those related to viridans streptococci. There have been reports of endovascular infections (predominantly endocarditis) and also of acute invasive infections. Few previous reports are available of cutaneous infection.

  17. Timing shifts due to NIF beam repointing

    SciTech Connect

    Koch, J

    2007-08-15

    Repointing a NIF beam to hit a target position off target chamber center (TCC) will introduce a timing shift due to changes in the light pathlength. This shift could be important for target experiment requirements even for targets placed at TCC, since beam timing test shots will place beams up to 15 mm off TCC in order to spatially separate them on foil targets. In particular, timing errors due to beam repointing need to be considered against the 30 ps RMS timing requirement. Since the repointing process will keep the beam passing through a fixed point in the final optics assembly (the conversion crystal) by tip/tilt adjustments of two turning mirrors (LM5 and LM7), the problem naturally divides into two parts: Timing offsets past the conversion crystal due to target positioning changes, and timing offsets behind the fixed point on the conversion crystal due to turning mirror adjustments. Timing offsets past the conversion crystal can be significant, but are trivial to calculate exactly; however, an exact calculation of timing offsets behind the fixed point on the conversion crystal would require a three-dimensional optomechanical raytrace model to be developed for every beamline, and this would be difficult and expensive. In this memo, I estimate the magnitude of timing offsets due to pathlength changes behind the conversion crystal by analysis of a worst-case model. I conclude that these timing offsets are insignificant compared with the current allocation in the 30 ps RMS timing requirement, and that more detailed raytrace modeling of individual beams is not necessary.

  18. Molecular Genetic Studies of Bone Mechanical Strain and of Pedigrees with Very High Bone Density

    DTIC Science & Technology

    2009-11-01

    osteoblast derived IGF caused by varying bone size ( periosteal circumference). As shown in KO mouse produces mechanical strain equivalent to 9N load in...It is known that ap pressure on the periosteal on the periosteal surface o response to loading by fou Figure 3: Cros externally load pQCT after 12...strain on the bone or due to the four-point bending technique produces a considerable amount of new bone formation 8 Dr. Subburaman Mohan 9 periosteal

  19. Electrical Properties of Materials for Elevated Temperature Resistance Strain Gage Application. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen

    1987-01-01

    The objective was to study the electrical resistances of materials that are potentially useful as resistance strain gages at 1000 C. Transition metal carbides and nitrides, boron carbide and silicon carbide were selected for the experimental phase of this research. Due to their low temperature coefficient of resistance and good stability, TiC, ZrC, B sub 4 C and beta-SiC are suggested as good candidates for high temperature resistance strain gage applications.

  20. Usefulness of Sau-PCR for molecular epidemiology of nosocomial outbreaks due to Burkholderia cepacia which occurred in a local hospital in Guangzhou, China.

    PubMed

    Yan, He; Shi, Lei; Alam, M J; Li, Lin; Yang, Liansheng; Yamasaki, Shinji

    2008-05-01

    The aim of the present study was to determine the source of nosocomial outbreak due to Burkholderia cepacia by molecular techniques. A total of 11 B. cepacia strains were isolated; nine from blood and one from sputum of patients without cystic fibrosis, and one from reverse osmosis water at a local hospital in Guangzhou, China. Analyses of 11 strains by the Sau-PCR assay and pulsed-field gel electrophoresis revealed that nine strains obtained from the blood of outpatients in a hemodialysis unit and one strain from reverse osmosis water had identical DNA profiles, indicating that the reverse osmosis water supply could be a source of infection.

  1. Stress-strain state and durability of mechanically inhomogeneous welds under low-cycle loading

    NASA Astrophysics Data System (ADS)

    Brazenas, A.; Daunis, M.

    2008-02-01

    Relations are proposed for the determination of the stress-strain state, strength, and life of butt welds with mild and hard interlayers under cyclic elastoplastic tension-compression. The accumulation of cyclic and quasistatic damages is determined with allowance for the redistribution of the cyclic elastoplastic strains and hardness of the stress state due to changes in the cyclic properties of separate regions of welds. The theoretical distribution of cyclic strains and the durability of welds under cyclic elastoplastic loading are supported by experimental data

  2. Strain induced electronic structure changes in magnetic transition metal oxides thin films

    SciTech Connect

    van der Laan, G.; Chopdekar, R.V.; Suzuki, Y.; Arenholz, E.

    2010-07-08

    We show that the angular dependence of x-ray magnetic circular dichroism (XMCD) is strongly sensitive to strain-induced electronic structure changes in magnetic transition metal oxides. We observe a pronounced dependence of the XMCD spectral shape on the experimental geometry as well as nonvanishing XMCD with distinct spectral features in transverse geometry in compressively strained MnCr{sub 2}O{sub 4} films. The angular dependent XMCD can be described as a sum over an isotropic and anisotropic contribution, the latter linearly proportional to the axial distortion due to strain. The XMCD spectra are well reproduced by atomic multiplet calculations.

  3. Effect of pre-strain on mechanical properties and deformation induced transformation of 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Zulfi, Fahri R.; Korda, Akhmad A.

    2016-08-01

    Effect of pre-strain on mechanical properties and deformation induced phase transformation of 304 stainless steel under tensile deformation has been studied. Pre-strain with the variation percentage of deformation was applied to the tensile test specimens. Tensile and hardness testing were carried out after pre-strain to study the mechanical properties change. Deformation induced phase transformation was investigated by using X-ray diffraction and optical microscope. XRD study indicates that metastable austenite transforms to martensite due to deformation. The martensite volume fraction increases with the increase in percentage of deformation. The increase in strength and hardness were associated with an increase in the volume fraction of martensite.

  4. Effect of pre-strain on ratcheting behavior of A668 Class D steel

    NASA Astrophysics Data System (ADS)

    Tripathy, S.; Mondal, A. K.; Dutta, K.

    2016-02-01

    The aim of this investigation is to study the effect pre-strain (0%, 2%, 4% and 8%) on ratcheting behavior of ASTM A668 Class D steel in different heat treatment conditions (normalized and hardened-tempered). Ratcheting tests were carried out at room temperature on cylindrical specimens having 12.5 mm gauge length and 6 mm gauge diameter. The results include reduced strain accumulation with increasing prestrain level due to work hardening of the pre-strained samples. Further, cyclic hardening takes place during ratcheting deformation.

  5. Sensing the earth crustal deformation with nano-strain resolution fiber-optic sensors.

    PubMed

    Liu, Qingwen; He, Zuyuan; Tokunaga, Tomochika

    2015-06-01

    Crustal deformation measurement with a high resolution on the order of nano-strains in static to low frequency region is required for geophysical research. Optical fiber sensors are very attractive in this research field due to their unique advantages including high resolution, small size and easy deployment. In this paper, a fiber optic strain sensor with nano-strain-resolution and large measurement range for sensing the earth crustal deformation is reported. With this sensor the tide induced crustal deformation and the seismic wave were successfully recorded in field experiments.

  6. Modulations of thermal properties of graphene by strain-induced phonon engineering

    NASA Astrophysics Data System (ADS)

    Tada, Kento; Funatani, Takashi; Konabe, Satoru; Sasaoka, Kenji; Ogawa, Matsuto; Souma, Satofumi; Yamamoto, Takahiro

    2017-02-01

    Modulation of the thermal properties of graphene due to strain-induced phononic band engineering was theoretically investigated by first-principles calculations based on the density functional theory. The high-energy phonon modes are found to exhibit softening owing to the strain, whereas a low-energy acoustic mode (out-of-plane mode) exhibits hardening. Moreover, the dispersion relation of the out-of-plane mode associated with the strain essentially changes from quadratic (∝ k 2) to linear (∝ k). Accordingly, the temperature dependence of the low-temperature specific heat also changes from linear (∝ T) to quadratic (∝ T 2).

  7. Geometric treatment of conduction electron scattering by crystal lattice strains and dislocations

    SciTech Connect

    Viswanathan, Koushik; Chandrasekar, Srinivasan

    2014-12-28

    The problem of conduction electron scattering by inhomogeneous crystal lattice strains is addressed using a tight-binding formalism and the differential geometric treatment of deformations in solids. In this approach, the relative positions of neighboring atoms in a strained lattice are naturally taken into account, even in the presence of crystal dislocations, resulting in a fully covariant Schrödinger equation in the continuum limit. Unlike previous work, the developed formalism is applicable to cases involving purely elastic strains as well as discrete and continuous distributions of dislocations—in the latter two cases, it clearly demarcates the effects of the dislocation strain field and core. It also differentiates between elastic and plastic strain contributions, respectively. The electrical resistivity due to the strain field of edge dislocations is then evaluated and the resulting numerical estimate for Cu shows good agreement with reported experimental values. This indicates that the electrical resistivity of edge dislocations in metals is not entirely due to the core, contrary to current models. Application to the study of strain effects in constrained quantum systems is also discussed.

  8. A Numerical Investigation of the Strain Effect on Saturation Optical Intensity in Electroabsorption Modulators Based on Asymmetric Intra-step-barrier Coupled Double Strained Quantum Wells

    NASA Astrophysics Data System (ADS)

    Abedi, Kambiz

    2011-12-01

    In this paper, the strain effect on saturation optical intensity in electroabsorption modulators (EAMs) based on asymmetric intra-step-barrier coupled double strained quantum well (AICD-SQWs) active region is theoretically investigated and compared with intra-step quantum well (IQW) structure. For this purpose, the thermionic emission and tunneling escape processes are taken into account and the escape times of photogenerated carriers are calculated. Then, the electroabsorption coefficient is calculated for different well strains for TE input light polarization. Finally, the saturation optical intensity of electroabsorption modulators with AICD-SQW structures in comparison with IQW structure is evaluated. Numerical results show that the tensile strain of well has the most significant effect on the saturation optical intensity of electroabsorption modulators with AICD-SQW structures due to reduction in escape times.

  9. Multiplicative earthquake likelihood models incorporating strain rates

    NASA Astrophysics Data System (ADS)

    Rhoades, D. A.; Christophersen, A.; Gerstenberger, M. C.

    2017-01-01

    SUMMARYWe examine the potential for <span class="hlt">strain</span>-rate variables to improve long-term earthquake likelihood models. We derive a set of multiplicative hybrid earthquake likelihood models in which cell rates in a spatially uniform baseline model are scaled using combinations of covariates derived from earthquake catalogue data, fault data, and <span class="hlt">strain</span>-rates for the New Zealand region. Three components of the <span class="hlt">strain</span> rate estimated from GPS data over the period 1991-2011 are considered: the shear, rotational and dilatational <span class="hlt">strain</span> rates. The hybrid model parameters are optimised for earthquakes of M 5 and greater over the period 1987-2006 and tested on earthquakes from the period 2012-2015, which is independent of the <span class="hlt">strain</span> rate estimates. The shear <span class="hlt">strain</span> rate is overall the most informative individual covariate, as indicated by Molchan error diagrams as well as multiplicative modelling. Most models including <span class="hlt">strain</span> rates are significantly more informative than the best models excluding <span class="hlt">strain</span> rates in both the fitting and testing period. A hybrid that combines the shear and dilatational <span class="hlt">strain</span> rates with a smoothed seismicity covariate is the most informative model in the fitting period, and a simpler model without the dilatational <span class="hlt">strain</span> rate is the most informative in the testing period. These results have implications for probabilistic seismic hazard analysis and can be used to improve the background model component of medium-term and short-term earthquake forecasting models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25503536','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25503536"><span><span class="hlt">Strain</span> effects on oxygen migration in perovskites.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mayeshiba, Tam; Morgan, Dane</p> <p>2015-01-28</p> <p>Fast oxygen transport materials are necessary for a range of technologies, including efficient and cost-effective solid oxide fuel cells, gas separation membranes, oxygen sensors, chemical looping devices, and memristors. <span class="hlt">Strain</span> is often proposed as a method to enhance the performance of oxygen transport materials, but the magnitude of its effect and its underlying mechanisms are not well-understood, particularly in the widely-used perovskite-structured oxygen conductors. This work reports on an ab initio prediction of <span class="hlt">strain</span> effects on migration energetics for nine perovskite systems of the form LaBO3, where B = [Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Ga]. Biaxial <span class="hlt">strain</span>, as might be easily produced in epitaxial systems, is predicted to lead to approximately linear changes in migration energy. We find that tensile biaxial <span class="hlt">strain</span> reduces the oxygen vacancy migration barrier across the systems studied by an average of 66 meV per percent <span class="hlt">strain</span> for a single selected hop, with a low of 36 and a high of 89 meV decrease in migration barrier per percent <span class="hlt">strain</span> across all systems. The estimated range for the change in migration barrier within each system is ±25 meV per percent <span class="hlt">strain</span> when considering all hops. These results suggest that <span class="hlt">strain</span> can significantly impact transport in these materials, e.g., a 2% tensile <span class="hlt">strain</span> can increase the diffusion coefficient by about three orders of magnitude at 300 K (one order of magnitude at 500 °C or 773 K) for one of the most <span class="hlt">strain</span>-responsive materials calculated here (LaCrO3). We show that a simple elasticity model, which assumes only dilative or compressive <span class="hlt">strain</span> in a cubic environment and a fixed migration volume, can qualitatively but not quantitatively model the <span class="hlt">strain</span> dependence of the migration energy, suggesting that factors not captured by continuum elasticity play a significant role in the <span class="hlt">strain</span> response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4222745','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4222745"><span>Distribution of Nontuberculous Mycobacteria <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Aim Mycobacteria other than tuberculosis (MOTT) cause increasingly serious infections especially in immunosuppressive patients by direct transmission from the environment or after colonization. However, identification of these species is difficult because of the cost and difficulties in defining to species level. Identification and distribution of these species can help clinician in the choice of treatment. Materials and methods A total of 90 MOTT <span class="hlt">strains</span> obtained from four different centers were included in the study. These <span class="hlt">strains</span> were identified by sequence analysis of 16S rRNA and Hsp65 genetic regions. Results Accordingly, within the 90 MOTT <span class="hlt">strains</span>, 17 different species were identified. In order of frequency, these species were M. gordonea (n = 21), M. abscessus (n = 13), M. lentiflavum (n = 9), M. fortuitum (n = 8), M. intracellulare (n = 6), M. kumamotonense (n = 6), M. neoaurum (n = 5), M. chimaera (n = 5), M. alvei (n = 5), M. peregrinum (n = 3), M. canariasense (n = 3), M. flavescens (n = 1), M. mucogenicum (n = 1), M. chelona (n = 1), M. elephantis (n = 1), M. terrae (n = 1) and M. xenopi (n = 1). Most frequently identified MOTT species according to the geographical origin were as follows: M. abscessus was the most common species either in Istanbul or Malatya regions (n = 6, n = 6, consequently). While M. kumamotonense was the most frequent species isolated from Ankara region (n = 6), M. gordonea was the most common for Samsun region (n = 14). Conclusion Our study revealed that frequency of MOTT varies depending on the number of clinical samples and that frequency of these species were affected by the newly identified species as a result of the use of novel molecular methods. In conclusion, when establishing diagnosis and treatment methods, it is important to know that infections caused by unidentified MOTT species may vary according to the regions in Turkey. The results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28093648','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28093648"><span>Predicting cell viability within tissue scaffolds under equiaxial <span class="hlt">strain</span>: multi-scale finite element model of collagen-cardiomyocytes constructs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Elsaadany, Mostafa; Yan, Karen Chang; Yildirim-Ayan, Eda</p> <p>2017-01-16</p> <p>Successful tissue engineering and regenerative therapy necessitate having extensive knowledge about mechanical milieu in engineered tissues and the resident cells. In this study, we have merged two powerful analysis tools, namely finite element analysis and stochastic analysis, to understand the mechanical <span class="hlt">strain</span> within the tissue scaffold and residing cells and to predict the cell viability upon applying mechanical <span class="hlt">strains</span>. A continuum-based multi-length scale finite element model (FEM) was created to simulate the physiologically relevant equiaxial <span class="hlt">strain</span> exposure on cell-embedded tissue scaffold and to calculate <span class="hlt">strain</span> transferred to the tissue scaffold (macro-scale) and residing cells (micro-scale) upon various equiaxial <span class="hlt">strains</span>. The data from FEM were used to predict cell viability under various equiaxial <span class="hlt">strain</span> magnitudes using stochastic damage criterion analysis. The model validation was conducted through mechanically <span class="hlt">straining</span> the cardiomyocyte-encapsulated collagen constructs using a custom-built mechanical loading platform (EQUicycler). FEM quantified the <span class="hlt">strain</span> gradients over the radial and longitudinal direction of the scaffolds and the cells residing in different areas of interest. With the use of the experimental viability data, stochastic damage criterion, and the average cellular <span class="hlt">strains</span> obtained from multi-length scale models, cellular viability was predicted and successfully validated. This methodology can provide a great tool to characterize the mechanical stimulation of bioreactors used in tissue engineering applications in providing quantification of mechanical <span class="hlt">strain</span> and predicting cellular viability variations <span class="hlt">due</span> to applied mechanical <span class="hlt">strain</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22490733','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22490733"><span>I-V characteristics of in-plane and out-of-plane <span class="hlt">strained</span> edge-hydrogenated armchair graphene nanoribbons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cartamil-Bueno, S. J. E-mail: rbolivar@ugr.es; Rodríguez-Bolívar, S. E-mail: rbolivar@ugr.es</p> <p>2015-06-28</p> <p>The effects of tensile <span class="hlt">strain</span> on the current-voltage (I-V) characteristics of hydrogenated-edge armchair graphene nanoribbons are investigated by using DFT theory. The <span class="hlt">strain</span> is introduced in two different ways related to the two types of systems studied in this work: in-plane <span class="hlt">strained</span> systems (A) and out-of-plane <span class="hlt">strained</span> systems <span class="hlt">due</span> to bending (B). These two kinds of <span class="hlt">strain</span> lead to make a distinction among three cases: in-plane <span class="hlt">strained</span> systems with <span class="hlt">strained</span> electrodes (A1) and with unstrained electrodes (A2), and out-of-plane homogeneously <span class="hlt">strained</span> systems with unstrained, fixed electrodes (B). The systematic simulations to calculate the electronic transmission between two electrodes were focused on systems of 8 and 11 dimers in width. The results show that the differences between cases A2 and B are negligible, even though the <span class="hlt">strain</span> mechanisms are different: in the plane case, the <span class="hlt">strain</span> is uniaxial along its length; while in the bent case, the <span class="hlt">strain</span> is caused by the arc deformation. Based on the study, a new type of nanoelectromechanical system solid state switching device is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70023644','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70023644"><span>Crustal displacements <span class="hlt">due</span> to continental water loading</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Van Dam, T.; Wahr, J.; Milly, P.C.D.; Shmakin, A.B.; Blewitt, G.; Lavallee, D.; Larson, K.M.</p> <p>2001-01-01</p> <p>The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (??rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional <span class="hlt">strains</span> are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ??rM with observed Global Positioning System (GPS) heights (??rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ??rO time series are adjusted by ??rM, their variances are reduced, on average, by an amount equal to the variance of the ??rM. Of the ??rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ??rM. The ??rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010114890&hterms=water+storage+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bstorage%2Bpressure','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010114890&hterms=water+storage+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bstorage%2Bpressure"><span>Crustal Displacements <span class="hlt">Due</span> to Continental Water Loading</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>vanDam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallee, D.; Larson, K. M.</p> <p>2001-01-01</p> <p>The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (delta-r(sub M)) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm with ranges up to 30 mm, and are predominantly annual in character. Regional <span class="hlt">strains</span> are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare delta-r(sub M) with observed Global Positioning System (GPS) heights (delta-r(sub O)) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the delta-r(sub O) time series are adjusted by delta-r(sub M), their variances are reduced, on average, by an amount equal to the variance of the delta-r(sub M). Of the delta-r(sub O) time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the delta-r(sub M). The delta-r(sub M) time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3505779','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3505779"><span>Fingernail Onychomycosis <span class="hlt">Due</span> to Aspergillus niger</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kim, Dong Min; Ha, Gyoung Yim; Sohng, Seung Hyun</p> <p>2012-01-01</p> <p>Onychomycosis is usually caused by dermatophytes, but some species of nondermatophytic molds and yeasts are also associated with nail invasion. Aspergillus niger is a nondermatophytic mold which exists as an opportunistic filamentous fungus in all environments. Here, we report a case of onychomycosis caused by A. niger in a 66-year-old female. The patient presented with a black discoloration and a milky white base and onycholysis on the proximal portion of the right thumb nail. Direct microscopic examination of scrapings after potassium hydroxide (KOH) preparation revealed dichotomous septate hyphae. Repeated cultures on Sabouraud's dextrose agar (SDA) without cycloheximide produced the same black velvety colonies. No colony growth occurred on SDA with cycloheximide slants. Biseriate phialides covering the entire vesicle with radiate conidial heads were observed on the slide culture. The DNA sequence of the internal transcribed spacer region of the clinical sample was a 100% match to that of A. niger <span class="hlt">strain</span> ATCC 16888 (GenBank accession number AY373852). A. niger was confirmed by KOH mount, colony identification, light microscopic morphology, and DNA sequence analysis. The patient was treated orally with 250 mg terbinafine daily and topical amorolfine 5% nail lacquer for 3 months. As a result, the patient was completely cured clinically and mycologically. PMID:23197914</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23866658','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23866658"><span>Physicians in transition: practice <span class="hlt">due</span> diligence.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Paterick, Timothy E</p> <p>2013-01-01</p> <p>The landscape of healthcare is changing rapidly. That landscape is now a business model of medicine. That rapid change resulting in a business model is affecting physicians professionally and personally. The new business model of medicine has led to large healthcare organizations hiring physicians as employees. The role of a physician as an employee has many limitations in terms of practice and personal autonomy. Employed physicians sign legally binding employment agreements that are written by the legal team working for the healthcare organization. Thus physicians should practice <span class="hlt">due</span> diligence before signing the employment agreement. "<span class="hlt">Due</span> diligence" refers to the care a reasonable person should take before entering into an agreement with another party. That reasonable person should seek expertise to represent his or her interests when searching a balanced agreement between the physician and organization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17907889','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17907889"><span>[Acute renal failure <span class="hlt">due</span> to sulfadiazine crystalluria].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>de la Prada Alvarez, F J; Prados Gallardo, A M; Tugores Vázquez, A; Uriol Rivera, M; Morey Molina, A</p> <p>2007-05-01</p> <p>Focal necrotizing encephalitis <span class="hlt">due</span> to Toxoplasma gondii infection represents one of the most common opportunistic infection in patients with the acquired inmunodeficiency syndrome (AIDS), and the treatment is commonly with a combination sulphadiazine, and pyrimethamine. A major side effect of sulfadiazine therapy is the occurrence of crystallization in the urinary collecting system. We report a patient with AIDS and Toxoplasmic encephalitis treated with sulfadiazine who developed acute renal failure. Renal ultrasound demonstrated echogenic areas within the renal parenchyma, presumed to be sulfa crystals. Renal failure and ultrasound findings resolved rapidly with hydratation and administration of alkali. Patients infected with AIDS frequently have characteristic that increase intratubular crystal precipitation and they require treatment with one or more of the drugs that are associated with crystal-induced renal failure. Controlled alkalinization of the urine and high fluid intake are recommended for prophylaxis of crystalluria. The literature concerning crystalluria and renal failure <span class="hlt">due</span> to sulfadiazine is reviewed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27440959','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27440959"><span>Fixed drug eruption <span class="hlt">due</span> to levocetirizine.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jhaj, Ratinder; Asati, Dinesh Prasad; Chaudhary, Deepa</p> <p>2016-01-01</p> <p>A fixed drug eruption (FDE) is a cutaneous adverse drug reaction <span class="hlt">due</span> to Type IV or delayed cell-mediated hypersensitivity. Antihistamines, which antagonize the action of histamine during an allergic reaction by blocking the H1 histamine receptors, are used routinely for the treatment of various allergic disorders such as urticaria, eczemas, and also in itchy lesions of skin like scabies. Levocetirizine, an active (R)-enantiomer of cetirizine, is a newer or second generation antihistamine, with more specific actions and fewer side effects, including cutaneous reactions. FDE <span class="hlt">due</span> to levocetirizine as well as with cetirizine are rare. We report a case of levocetirizine induced FDE in a 49-year-old male patient with scabies. The patient had a history of cetirizine induced FDE in the past.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4936078','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4936078"><span>Fixed drug eruption <span class="hlt">due</span> to levocetirizine</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jhaj, Ratinder; Asati, Dinesh Prasad; Chaudhary, Deepa</p> <p>2016-01-01</p> <p>A fixed drug eruption (FDE) is a cutaneous adverse drug reaction <span class="hlt">due</span> to Type IV or delayed cell-mediated hypersensitivity. Antihistamines, which antagonize the action of histamine during an allergic reaction by blocking the H1 histamine receptors, are used routinely for the treatment of various allergic disorders such as urticaria, eczemas, and also in itchy lesions of skin like scabies. Levocetirizine, an active (R)-enantiomer of cetirizine, is a newer or second generation antihistamine, with more specific actions and fewer side effects, including cutaneous reactions. FDE <span class="hlt">due</span> to levocetirizine as well as with cetirizine are rare. We report a case of levocetirizine induced FDE in a 49-year-old male patient with scabies. The patient had a history of cetirizine induced FDE in the past. PMID:27440959</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IJTFM.129....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IJTFM.129....1S"><span>Information Security <span class="hlt">due</span> to Electromagnetic Environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sekiguchi, Hidenori; Seto, Shinji</p> <p></p> <p>Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage <span class="hlt">due</span> to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security <span class="hlt">due</span> to electromagnetic emissions from information technology equipments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12482279','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12482279"><span>Ocular injury <span class="hlt">due</span> to bungee jumping.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Curtis, Edward B; Collin, H Barry</p> <p>1999-01-01</p> <p>BACKGROUND: Bungee jumping is a well-established recreational activity in New Zealand and Australia which may be associated with injuries to the eyes and other tissues. CASE HISTORY: A patient with a retinal haemorrhage which resulted from bungee jumping is reported and the clinical characteristics described. DISCUSSION: There have been several reports of injury <span class="hlt">due</span> to bungee jumping. The types of ocular injury are reviewed and the aetiological theories discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA630417','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA630417"><span>Insulator Surface Flashover <span class="hlt">Due</span> to UV Illumination</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2009-06-01</p> <p>The surface of an insulator under vacuum and under electrical charge will flashover when illuminated by a critical dose of ultra-violet (UV...fluence (energy per unit area) required to induce surface flashover of vacuum insulators for some candid insulator materials: High Density... Insulator Surface Flashover <span class="hlt">Due</span> to UV Illumination1 J. B. Javedani, T.L. Houck, D.A. Lahowe, G.E. Vogtlin and D.A. Goerz Lawrence Livermore</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26437988','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26437988"><span>Sprue-like enteropathy <span class="hlt">due</span> to olmesartan.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Muñoz-Muñoz, Cándido; López-Vivancos, Josefa; Huaman, Walter; García-Cors, Montserrat</p> <p>2015-10-01</p> <p>A case of spue-like enteropathy <span class="hlt">due</span> to olmesartan is reported to draw attention to this disease, given the high frequency of use of this drug and the difficulty of diagnosis if the entity if it is not known. In his journal one case was published as Clinical Note in 2014 and we wish to emphasize the importance of knowledge about this relatively new entity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21888496','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21888496"><span>Generalized pustular eruptions <span class="hlt">due</span> to terbinafine.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ozturk, Gunseli; Turk, Bengu Gerceker; Karaca, Nezih; Karaarslan, Isil Kilinc; Ertekin, Banu; Ertam, Ilgen; Kazandi, Alican; Kandiloglu, Gulsen</p> <p>2012-03-01</p> <p>Terbinafine, a widely used antifungal agent, may rarely cause cutaneous side effects with an incidence of 2.7%. Generalized pustular eruptions are quite uncommon but severe adverse cutaneous reactions of terbinafine have been reported. The main pustular eruptions <span class="hlt">due</span> to terbinafine include acute generalized exanthematous pustulosis and drug induced pustular psoriasis. In this report, two cases of acute generalized exanthematous pustulosis and one case of generalized pustular psoriasis triggered with terbinafine are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011343','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011343"><span>Exposure fluctuations of astronauts <span class="hlt">due</span> to orientation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, John W.; Nealy, John E.; Wood, James S.; Qualls, Gary; Atwell, William; Shinn, Judy L.; Simonsen, Lisa C.</p> <p>1993-01-01</p> <p>The dose incurred in an anisotropic environment depends on the orientation of the astronaut's body relative to the direction of the radiation field. The fluctuations in exposure of specific organs <span class="hlt">due</span> to astronaut orientation are found to be a factor of 2 or more in a typical space habitation module and typical space radiations. An approximation function is found that overestimates astronaut exposure in most cases studied and is recommended as a shield design guide for future space missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5293127','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5293127"><span>Exposure fluctuations of astronauts <span class="hlt">due</span> to orientation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wilson, J.W.; Nealy, J.E.; Wood, J.S.; Qualls, G.; Atwell, W.; Shinn, J.L.; Simonsen, L.C.</p> <p>1993-09-01</p> <p>The dose incurred in an anisotropic environment depends on the orientation of the astronaut's body relative to the direction of the radiation field. The fluctuations in exposure of specific organs <span class="hlt">due</span> to astronaut orientation are found to be a factor of 2 or more in a typical space habitation module and typical space radiations. An approximation function is found that overestimates astronaut exposure in most cases studied and is recommended as a shield design guide for future space missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25573494','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25573494"><span>Cholestatic hepatitis <span class="hlt">due</span> to Ecballium elaterium ingestion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bizid, Sondès; Sabbah, Mériam; Msakni, Issam; Ben Slimene, Baha; Mohamed, Ghanem; Bouali, Riadh; Ben Abdallah, Hatem; Abdelli, Nabil</p> <p>2015-10-01</p> <p>Ecballium elaterium is an herbaceous plant belonging to the Cucurbitaceae family. This plant is fairly common in the Mediterranean regions. It is frequently consumed in infusion, mixture of fruit or even in aerosol in cases of fever or flu. This plant is known for its respiratory and ocular toxicity. Hepatotoxicity has never been described in the literature. We report a case of acute cholestatic hepatitis <span class="hlt">due</span> to Ecballium elaterium in a 39 years old patient, with no past medical history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5353830','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5353830"><span>Neonatal cholestasis <span class="hlt">due</span> to primary sclerosing cholangitis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shetty, Naman Sadanand; Shah, Ira</p> <p>2016-01-01</p> <p>Neonatal cholestasis is rarely caused <span class="hlt">due</span> to primary sclerosing cholangitis, which is an inflammatory disease of the bile ducts, which results in obstructive fibrosis of the ducts. A 7-month-old male child presented with jaundice along with high-colored urine and clay-colored stools since birth. Liver biopsy showed mild bile duct proliferation with cholangioles showing bile and thrombi suggestive of primary sclerosing cholangitis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010019706','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010019706"><span>Contamination Effects <span class="hlt">Due</span> to Space Environmental Interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Philip T.; Paquin, Krista C. (Technical Monitor)</p> <p>2001-01-01</p> <p>Molecular and particulate contaminants are commonly generated from the orbital spacecraft operations that are under the influence of the space environment. Once generated, these contaminants may attach to the surfaces of the spacecraft or may remain in the vicinity of the spacecraft. In the event these contaminants come to rest on the surfaces of the spacecraft or situated in the line-of-sight of the observation path, they will create various degrees of contamination effect which may cause undesirable effects for normal spacecraft operations, There will be circumstances in which the spacecraft may be subjected to special space environment <span class="hlt">due</span> to operational conditions. Interactions between contaminants and special space environment may alter or greatly increase the contamination effect <span class="hlt">due</span> to the synergistic effect. This paper will address the various types of contamination generation on orbit, the general effects of the contamination on spacecraft systems, and the typical impacts on the spacecraft operations <span class="hlt">due</span> to the contamination effect. In addition, this paper will explain the contamination effect induced by the space environment and will discuss the intensified contamination effect resulting from the synergistic effect with the special space environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..DPPPP1062D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..DPPPP1062D"><span>Density Limit <span class="hlt">due</span> to SOL Convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Ippolito, D. A.; Myra, J. R.; Russell, D. A.</p> <p>2004-11-01</p> <p>Recent measurements on C-Mod(M. Greenwald, Plasma Phys. Contr. Fusion 44), R27 (2002). suggest there is a density limit <span class="hlt">due</span> to rapid convection in the SOL: this region starts in the far SOL but expands inward to the separatrix as the density approaches the Greenwald limit. This idea is supported by a recent analysis(D. A. Russell et al., Lodestar Report LRC-04-99 (2004).) of a 3D BOUT code turbulence simulation(X. Q. Xu et al., Bull. APS 48), 184 (2003), paper KP1-20. with neutral fueling of the X-point region. Our work suggests that rapid outwards convection of plasma by turbulent coherent structures (``blobs'') occurs when the X-point collisionality is sufficiently large. Here, we calculate a density limit <span class="hlt">due</span> to loss of thermal equilibrium in the edge plasma <span class="hlt">due</span> to rapid radial convective heat transport. We expect a synergistic effect between blob convection and X-point cooling. The cooling increases the parallel resistivity at the X-point, ``disconnects'' the blobs electrically from the sheaths, and increases their radial velocity,(D.A. D'Ippolito et al., 2004 Sherwood Meeting, paper 1C 43.) which in turn further cools the X-points. Progress on a theoretical model will be reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26902321','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26902321"><span>Comparison of <span class="hlt">Strain</span> Rosettes and Digital Image Correlation for Measuring Vertebral Body <span class="hlt">Strain</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gustafson, Hannah; Siegmund, Gunter; Cripton, Peter</p> <p>2016-05-01</p> <p><span class="hlt">Strain</span> gages are commonly used to measure bone <span class="hlt">strain</span>, but only provide <span class="hlt">strain</span> at a single location. Digital image correlation (DIC) is an optical technique that provides the displacement, and therefore <span class="hlt">strain</span>, over an entire region of interest on the bone surface. This study compares vertebral body <span class="hlt">strains</span> measured using <span class="hlt">strain</span> gages and DIC. The anterior surfaces of 15 cadaveric porcine vertebrae were prepared with a <span class="hlt">strain</span> rosette and a speckled paint pattern for DIC. The vertebrae were loaded in compression with a materials testing machine, and two high-resolution cameras were used to image the anterior surface of the bones. The mean noise levels for the <span class="hlt">strain</span> rosette and DIC were 1 με and 24 με, respectively. Bland-Altman analysis was used to compare <span class="hlt">strain</span> from the DIC and rosette (excluding 44% of trials with some evidence of <span class="hlt">strain</span> rosette failure or debonding); the mean difference ± 2 standard deviations (SDs) was -108 με ± 702 με for the minimum (compressive) principal <span class="hlt">strain</span> and -53 με ± 332 με for the maximum (tensile) principal <span class="hlt">strain</span>. Although the DIC has higher noise, it avoids the relatively high risk we observed of <span class="hlt">strain</span> gage debonding. These results can be used to develop guidelines for selecting a method to measure <span class="hlt">strain</span> on bone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1723b0001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1723b0001D"><span>Modeling competition between yeast <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Gee, Maarten; van Mourik, Hilda; de Visser, Arjan; Molenaar, Jaap</p> <p>2016-04-01</p> <p>We investigate toxin interference competition between S. cerevisiae colonies grown on a solid medium. In vivo experiments show that the outcome of this competition depends strongly on nutrient availability and cell densities. Here we present a new model for S. cerevisiae colonies, calculating the local height and composition of the colonies. The model simulates yeast colonies that show a good fit to experimental data. Simulations of colonies that start out with a homogeneous mixture of toxin producing and toxin sensitive cells can display remarkable pattern formation, depending on the initial ratio of the <span class="hlt">strains</span>. Simulations in which the toxin producing and toxin sensitive species start at nearby positions clearly show that toxin production is advantageous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008msm..book..423C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008msm..book..423C"><span>Measuring <span class="hlt">Strain</span> in Semiconductor Nanostructures by Convergent Beam Electron Diffraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clément, L.; Rouviere, J.-L.; Cacho, F.; Pantel, R.</p> <p></p> <p>Convergent beam electron diffraction (CBED) experiments and simulations, and finite element calculations are used to measure the <span class="hlt">strain</span> and stress in a complex device such as a series of periodic MOS transistors. When approaching the transistor active regions, the HOLZ lines in the CBED patterns acquired in the silicon substrate, become increasingly broad. This HOLZ line broadening, which is <span class="hlt">due</span> to the relaxation of stress in the lamella, is used to determine quantitatively the <span class="hlt">strain</span> and stress in the thin lamella and then in the bulk device. Two parameters, the intrinsic material stresses in the NiSi and Si3N4 layers of the transistors, are successfully fitted by trial and error. These fitted values are, respectively, equal to 1.2 and 0.95GPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvB..90k5152S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvB..90k5152S"><span>Electronic structure of spontaneously <span class="hlt">strained</span> graphene on hexagonal boron nitride</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>San-Jose, Pablo; Gutiérrez-Rubio, A.; Sturla, Mauricio; Guinea, Francisco</p> <p>2014-09-01</p> <p>Hexagonal boron nitride substrates have been shown to dramatically improve the electric properties of graphene. Recently, it has been observed that when the two honeycomb crystals are close to perfect alignment, strong lattice distortions develop in graphene <span class="hlt">due</span> to the moiré adhesion landscape. Simultaneously, a gap opens at the Dirac point. Here, we derive a simple low-energy electronic model for graphene aligned with the substrate, taking into account spontaneous <span class="hlt">strains</span> at equilibrium and pseudogauge fields. We carry out a detailed characterization of the modified band structure, gap, local and global density of states, and band topology in terms of physical parameters. We show that the overall electronic structure is strongly modified by the spontaneous <span class="hlt">strains</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012itcb.book...99M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012itcb.book...99M"><span>Heat <span class="hlt">Strain</span> in Personal Protective Clothing: Challenges and Intervention Strategies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McLellan, T. M.; Daanen, H. A. M.</p> <p></p> <p>Humans rely on sweat evaporation during exercise in the heat to promote cooling and to maintain thermal homeostasis. In protective clothing, however, sweat evaporation is severely hampered and this may lead to uncompensable heat <span class="hlt">strain</span>, where core body temperature continues to rise leading to physical exhaustion and the cessation of work. The tolerance time depends on three main factors: (1) the initial core temperature that may be reduced by heat acclimation and pre-cooling, (2) the final core temperature, which can be increased <span class="hlt">due</span> to physical training, and (3) the rate of change in body core temperature, which is dependent on the thermal environment, work rate and individual factors like body composition. Methods to reduce heat <span class="hlt">strain</span> in protective clothing include: (1) increasing clothing permeability for air, (2) adjusting pacing strategy, including work/rest schedules, (3) physical training, and (4) cooling interventions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006APS..MARW25007W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006APS..MARW25007W"><span>Large-<span class="hlt">strain</span> deformation and fracture of tough hydrogels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Webber, Rebecca; Miquelard, Guillaume; Creton, Costantino; Gong, Jian Ping</p> <p>2006-03-01</p> <p>Highly-swollen, chemically-crosslinked hydrogels generally behave in a very brittle manner, fracturing suddenly after a small amount of reversible deformation. Because of their importance as biomaterials, it is useful to control and augment the resistance to fracture of these materials. Tougher, stronger hydrogels are emerging, and it is important to understand the structural origins of strength in these relatively robust, highly-swollen, polymer systems. We have investigated the rheological, mechanical and fracture properties of tough hydrogels, using novel testing techniques and focusing on the high-<span class="hlt">strain</span> compression and tension behavior. Results from large-<span class="hlt">strain</span> and fracture experiments were correlated to the chemical structure of the hydrogels. Because we believe that the mechanical properties of these tough hydrogels are <span class="hlt">due</span> to the presence of dissipative mechanisms at the molecular level, we have explored several methods of synthesis to create these materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvB..87l5418W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvB..87l5418W"><span>Pseudomagnetoexcitons in <span class="hlt">strained</span> graphene bilayers without external magnetic fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Zhigang; Fu, Zhen-Guo; Zheng, Fawei; Zhang, Ping</p> <p>2013-03-01</p> <p>We propose a <span class="hlt">strained</span> graphene double-layer (SGDL) system for detecting pseudomagnetoexcitons (PME) in the absence of external magnetic fields. The carriers in each graphene layer experience different strong pseudomagnetic fields (PMFs) <span class="hlt">due</span> to <span class="hlt">strain</span> engineering, which give rise to Landau quantization. The pseudo-Landau levels of electron-hole pairs under inhomogeneous PMFs in the SGDL are obtained analytically in the absence of Coulomb interactions. Based on the derived optical absorption selection rule for PMEs, we interpret the optical absorption spectra as indicating the formation of Dirac-type PMEs. We also predict that in the presence of inhomogeneous PMFs, the superfluidity-normal phase-transition temperature of PMEs is greater than that under homogeneous PMFs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EL....10956002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EL....10956002G"><span>Adsorption-induced <span class="hlt">strain</span> of a nanoscale silicon honeycomb</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grosman, A.; Puibasset, J.; Rolley, E.</p> <p>2015-03-01</p> <p>We report on systematic measurements of both adsorption and anisotropic mechanical deformations of mesoporous silicon, using heptane at room temperature. Porous Si obtained from highly doped (100) Si can be thought of as a nanoscale random honeycomb with pores parallel to the [001] axis. We show that <span class="hlt">strains</span> ε\\parallel and ε\\bot measured along and transversely to the pore axis exhibit a hysteretic behavior as a function of the fluid pressure, which is <span class="hlt">due</span> to the hysteresis in fluid adsorption. The pressure dependence of the <span class="hlt">strains</span> together with the independent measurement of the transverse stress, allows us to determine the biaxial transverse modulus and to estimate the longitudinal Young's modulus of porous Si. We argue that the value of these constants implies that Young's modulus of the 6 nm thick walls of the honeycomb is about 5 times smaller than that of bulk silicon, striking evidence of finite-size effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3497371','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3497371"><span>Phylogenetic Analysis and Polyphasic Characterization of Clavibacter michiganensis <span class="hlt">Strains</span> Isolated from Tomato Seeds Reveal that Nonpathogenic <span class="hlt">Strains</span> Are Distinct from C. michiganensis subsp. michiganensis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Durand, Karine; Orgeur, Geoffrey; Balidas, Samuel; Fricot, Céline; Bonneau, Sophie; Quillévéré, Anne; Audusseau, Corinne; Olivier, Valérie; Grimault, Valérie; Mathis, René</p> <p>2012-01-01</p> <p>The genus Clavibacter comprises one species and five subspecies of plant-pathogenic bacteria, four of which are classified as quarantine organisms <span class="hlt">due</span> to the high economic threat they pose. Clavibacter michiganensis subsp. michiganensis is one of the most important pathogens of tomato, but the recommended diagnostic tools are not satisfactory <span class="hlt">due</span> to false-negative and/or -positive results. To provide a robust analysis of the genetic relatedness among a worldwide collection of C. michiganensis subsp. michiganensis <span class="hlt">strains</span>, relatives (<span class="hlt">strains</span> from the four other C. michiganensis subspecies), and nonpathogenic Clavibacter-like <span class="hlt">strains</span> isolated from tomato, we performed multilocus sequence-based analysis and typing (MLSA and MLST) based on six housekeeping genes (atpD, dnaK, gyrB, ppK, recA, and rpoB). We compared this “framework” with phenotypic and genotypic characteristics such as pathogenicity on tomato, reaction to two antisera by immunofluorescence and to five PCR identification tests, and the presence of four genes encoding the main C. michiganensis subsp. michiganensis pathogenicity determinants. We showed that C. michiganensis subsp. michiganensis is monophyletic and is distinct from its closest taxonomic neighbors. The nonpathogenic Clavibacter-like <span class="hlt">strains</span> were identified as C. michiganensis using 16S rRNA gene sequencing. These <span class="hlt">strains</span>, while cross-reacting with C. michiganensis subsp. michiganensis identification tools, are phylogenetically distinct from the pathogenic <span class="hlt">strains</span> but belong to the C. michiganensis clade. C. michiganensis subsp. michiganensis clonal complexes linked <span class="hlt">strains</span> from highly diverse geographical origins and also <span class="hlt">strains</span> isolated over long periods of time in the same location. This illustrates the importance of seed transmission in the worldwide dispersion of this pathogen and its survival and adaptation abilities in a new environment once introduced. PMID:23001675</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhDT.......100Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhDT.......100Z"><span>Reliable local <span class="hlt">strain</span> characterization in silicon/silicon-germanium based electronic materials system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Wenjun</p> <p>2007-12-01</p> <p>For the first time, we developed a new approach combined with CBED and finite element (FE) modeling and quantitatively investigated the correlation of the <span class="hlt">strain</span> in a thin TEM sample with that in the bulk. The new method successfully determined the <span class="hlt">strain</span> in the <span class="hlt">strained</span> Si layer on a blanket <span class="hlt">strained</span> Si/SiGe wafer, in a good agreement with other measurements. The new results also gave some insight in <span class="hlt">strain</span> relaxation in a TEM sample. We found the [-1,-1,0] <span class="hlt">strain</span> component which is perpendicular to the TEM sample thinning direction stays the same in the TEM sample and in the bulk, while the [001]) <span class="hlt">strain</span> component is relaxed because it is along the same direction as the TEM sample thinning direction. This relaxation causes the deformation of the TEM foil and HOLZ line splitting. Therefore a clear CBED pattern can not be obtained from a TEM sample with a biaxial stain state. Our findings from a recessed SiGe PMOS test structure with a uniaxial compressive <span class="hlt">strain</span> showed a different <span class="hlt">strain</span> redistribution behavior. The data showed that the epsilonx [-1,1,0] <span class="hlt">strain</span> is actually more than 20% higher in a TEM sample than in the bulk. The epsilony [-1,-1,0] <span class="hlt">strain</span> which is parallel to the TEM sample thinning direction turns to tensile in the TEM sample <span class="hlt">due</span> to the loss of constraints, while it is zero in the bulk. The new results can explain our experimental data and others' (which could not be explained before) and are consistent with UV Raman measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5126507','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5126507"><span>The high-<span class="hlt">strain</span>-rate and spallation response of tantalum, Ta-10W, and T-111</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gray, G.T. III; Rollett, A.D.</p> <p>1991-01-01</p> <p>The compressive true stress-true response of tantalum, Ta-10W, and T-111 were found to depend on the applied <span class="hlt">strain</span> rate, in the range 0.001 to 7000 s{sup {minus}1}. The <span class="hlt">strain</span>-rate sensitivities of the flow stress of tantalum, Ta-10W, and T-111 a 1% <span class="hlt">strain</span> are 0.062, 0.031, and 0.024, respectively. The rates of <span class="hlt">strain</span> hardening in Tantalum, Ta-10W, and T-111 are seen to exhibit differing behavior with increasing <span class="hlt">strain</span> rate. The calculated average <span class="hlt">strain</span>-hardening rate in tantalum, {Theta}, for the quasi-static (0.001 s{sup {minus}1}) data at 25{degrees}C is 2080 MPa/unit <span class="hlt">strain</span>. The hardening rate at 3000s{sup {minus}1} at 25{degrees}C decreases to 846 MPa/unit <span class="hlt">strain</span>. Normalizing the work hardening rate in tantalum with the Taylor Factor for a random polycrystal, ({Theta} / (3.07){sup 2}), yields work hardening rates of {mu}/276 at quasi-static <span class="hlt">strain</span> rates and {mu}/680 at high-rates, assuming a shear modulus of 61 GPa for tantalum at room temperature. While the work hardening of all the tantalum-based materials are similar at quasi-static rates, alloying results in a small reduction in hardening rate. With increasing <span class="hlt">strain</span> rate, the work hardening rate in tantalum decreases by approximately a factor of two compared to the alloys. Alloying tantalum with substitutional or interstitial elements is thought to result in increased edge dislocation storage and screw dislocation cross-slip <span class="hlt">due</span> to interactions with the alloying elements at high <span class="hlt">strain</span> rates. 28 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030112383','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030112383"><span>Ceramic <span class="hlt">Strain</span> Gages for Use at Temperatures up to 1500 Celsius</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gregory, Otto; Fralick, Gustave (Technical Monitor)</p> <p>2003-01-01</p> <p>Indium-tin-oxide (ITO) thin film <span class="hlt">strain</span> gages were successfully demonstrated at temperatures beyond 1500 C. High temperature static <span class="hlt">strain</span> tests revealed that the piezoresistive response and electrical stability of the ceramic sensors depended on the thickness of the ITO films comprising the active <span class="hlt">strain</span> elements. When 2.5 microns-thick ITO films were employed as the active <span class="hlt">strain</span> elements, the piezoresistive response became unstable at temperatures above 1225 C. In contrast to this, ceramic sensors prepared with 5 microns-thick ITO were stable beyond 1430 C and sensors prepared with 8 microns-thick ITO survived more than 20 hr of operation at 1481 C. Very thick (10 microns) ITo <span class="hlt">strain</span> gages were extremely stable and responsive at 1528 C. ESCA depth profiles confirmed that an interfacial reaction between the ITO <span class="hlt">strain</span> gage and alumina substrate was responsible for the high temperature electrical stability observed. Similar improvements in high temperature stability were achieved by doping the active ITO <span class="hlt">strain</span> elements with aluminum. Several Sic-Sic CMC constant <span class="hlt">strain</span> beams were instrumented with ITO <span class="hlt">strain</span> gages and delivered to NASA for testing. <span class="hlt">Due</span> to the extreme surface roughness of the CMC substrates, new lithography techniques and surface preparation methods were developed. These techniques relied heavily on a combination of Sic and A12O3 cement layers to provide the necessary surface finish for efficient pattern transfer. Micro-contact printing using soft lithography and PDMS stamps was also used to successfully transfer the thin film <span class="hlt">strain</span> gage patterns to the resist coated CMC substrates. This latter approach has considerable potential for transferring the thin film <span class="hlt">strain</span> gage patterns to the extremely rough surfaces associated with the CMC's.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2680828','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2680828"><span>Simulation suggests that rapid activation of social distancing can arrest epidemic development <span class="hlt">due</span> to a novel <span class="hlt">strain</span> of influenza</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kelso, Joel K; Milne, George J; Kelly, Heath</p> <p>2009-01-01</p> <p>Background Social distancing interventions such as school closure and prohibition of public gatherings are present in pandemic influenza preparedness plans. Predicting the effectiveness of intervention strategies in a pandemic is difficult. In the absence of other evidence, computer simulation can be used to help policy makers plan for a potential future influenza pandemic. We conducted simulations of a small community to determine the magnitude and timing of activation that would be necessary for social distancing interventions to arrest a future pandemic. Methods We used a detailed, individual-based model of a real community with a population of approximately 30,000. We simulated the effect of four social distancing interventions: school closure, increased isolation of symptomatic individuals in their household, workplace nonattendance, and reduction of contact in the wider community. We simulated each of the intervention measures in isolation and in several combinations; and examined the effect of delays in the activation of interventions on the final and daily attack rates. Results For an epidemic with an R0 value of 1.5, a combination of all four social distancing measures could reduce the final attack rate from 33% to below 10% if introduced within 6 weeks from the introduction of the first case. In contrast, for an R0 of 2.5 these measures must be introduced within 2 weeks of the first case to achieve a similar reduction; delays of 2, 3 and 4 weeks resulted in final attack rates of 7%, 21% and 45% respectively. For an R0 of 3.5 the combination of all four measures could reduce the final attack rate from 73% to 16%, but only if introduced without delay; delays of 1, 2 or 3 weeks resulted in final attack rates of 19%, 35% or 63% respectively. For the higher R0 values no single measure has a significant impact on attack rates. Conclusion Our results suggest a critical role of social distancing in the potential control of a future pandemic and indicate that such interventions are capable of arresting influenza epidemic development, but only if they are used in combination, activated without delay and maintained for a relatively long period. PMID:19400970</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22475939','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22475939"><span>Nitrogen requirements of commercial wine yeast <span class="hlt">strains</span> during fermentation of a synthetic grape must.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gutiérrez, Alicia; Chiva, Rosana; Sancho, Marta; Beltran, Gemma; Arroyo-López, Francisco Noé; Guillamon, José Manuel</p> <p>2012-08-01</p> <p>Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each <span class="hlt">strain</span>, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast <span class="hlt">strains</span>. This task was carried out using statistical modeling techniques. The <span class="hlt">strains</span> PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than <span class="hlt">strains</span> ARM and TTA. Likewise, the <span class="hlt">strains</span> PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively <span class="hlt">due</span> to the increase in biomass because the <span class="hlt">strain</span> TTA, which showed the worst growth behavior, had the best fermentation activity. Some <span class="hlt">strains</span> may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the <span class="hlt">strains</span> showed the better and worse fermentation performance with arginine and ammonium, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22402932','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22402932"><span>Dirac points and van Hove singularities of silicene under uniaxial <span class="hlt">strain</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lin, Xianqing; Ni, Jun</p> <p>2015-04-28</p> <p>First-principles calculations have been performed to investigate the low energy electronic properties and van Hove singularities (VHSs) of silicene under uniaxial <span class="hlt">strain</span>. The Dirac points (DPs) persist when silicene is stretched uniaxially, while they are shifted away from the corners (K points) of the first Brillouin zone (FBZ). The relative positions of DPs with respect to the K points for silicene <span class="hlt">strained</span> along the armchair (AC) or zigzag (ZZ) direction show opposite tendency compared with <span class="hlt">strained</span> graphene, which is <span class="hlt">due</span> to the larger deformation of the unit cell of <span class="hlt">strained</span> silicene than that of <span class="hlt">strained</span> graphene. Moreover, for silicene under AC or ZZ <span class="hlt">strain</span>, the Fermi velocities around DPs along the positive and negative directions of the FBZ show rather significant difference. The nature of the VHS just above the Fermi energy undergoes a transition from the π* band to the σ* band for silicene under increasing AC or ZZ <span class="hlt">strain</span>. These observations suggest uniaxial <span class="hlt">strain</span> as an effective route to tune the electronic properties of silicene for potential applications in future electronic devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1538600','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1538600"><span>Immunochemical characterization of polysaccharide antigens from six clinical <span class="hlt">strains</span> of Enterococci</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hsu, Carolyn T; Ganong, Amanda L; Reinap, Barbara; Mourelatos, Zafiria; Huebner, Johannes; Wang, Julia Y</p> <p>2006-01-01</p> <p>Background Enterococci have become major nosocomial pathogens <span class="hlt">due</span> to their intrinsic and acquired resistance to a broad spectrum of antibiotics. Their increasing drug resistance prompts us to search for prominent antigens to develop vaccines against enterococci. Given the success of polysaccharide-based vaccines against various bacterial pathogens, we isolated and characterized the immunochemical properties of polysaccharide antigens from five <span class="hlt">strains</span> of Enterococcus faecalis and one <span class="hlt">strain</span> of vancomycin-resistant E. faecium. Results We cultured large batches of each <span class="hlt">strain</span>, isolated sufficient quantities of polysaccharides, analyzed their chemical structures, and compared their antigenic specificity. Three classes of polysaccharides were isolated from each <span class="hlt">strain</span>, including a polyglucan, a teichoic acid, and a heteroglycan composed of rhamnose, glucose, galactose, mannosamine, and glucosamine. The polyglucans from all six <span class="hlt">strains</span> are identical and appear to be dextran. Yields of the teichoic acids were generally low. The most abundant polysaccharides are the heteroglycans. The six heteroglycans are structurally different as evidenced by NMR spectroscopy. They also differ in their antigenic specificities as revealed by competitive ELISA. The heteroglycans are not immunogenic by themselves but conjugation to protein carriers significantly enhanced their ability to induce antibodies. Conclusion The six clinical <span class="hlt">strains</span> of enterococci express abundant, <span class="hlt">strain</span>-specific cell-surface heteroglycans. These polysaccharides may provide a molecular basis for serological typing of enterococcal <span class="hlt">strains</span> and antigens for the development of vaccines against multi-drug resistant enterococci. PMID:16836754</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3815844','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3815844"><span>Application of nitroarene dioxygenases in the design of novel <span class="hlt">strains</span> that degrade chloronitrobenzenes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ju, Kou‐San; Parales, Rebecca E.</p> <p>2009-01-01</p> <p>Summary Widespread application of chloronitrobenzenes as feedstocks for the production of industrial chemicals and pharmaceuticals has resulted in extensive environmental contamination with these toxic compounds, where they pose significant risks to the health of humans and wildlife. While biotreatment in general is an attractive solution for remediation, its effectiveness is limited with chloronitrobenzenes <span class="hlt">due</span> to the small number of <span class="hlt">strains</span> that can effectively mineralize these compounds and their ability to degrade only select isomers. To address this need, we created engineered <span class="hlt">strains</span> with a novel degradation pathway that reduces the total number of steps required to convert chloronitrobenzenes into compounds of central metabolism. We examined the ability of 2‐nitrotoluene 2,3‐dioxygenase from Acidovorax sp. <span class="hlt">strain</span> JS42, nitrobenzene 1,2‐dioxygenase (NBDO) from Comamonas sp. <span class="hlt">strain</span> JS765, as well as active‐site mutants of NBDO to generate chlorocatechols from chloronitrobenzenes, and identified the most efficient enzymes. Introduction of the wild‐type NBDO and the F293Q variant into Ralstonia sp. <span class="hlt">strain</span> JS705, a <span class="hlt">strain</span> carrying the modified ortho pathway for chlorocatechol metabolism, resulted in bacterial <span class="hlt">strains</span> that were able to sustainably grow on all three chloronitrobenzene isomers without addition of co‐substrates or co‐inducers. These first‐generation engineered <span class="hlt">strains</span> demonstrate the utility of nitroarene dioxygenases in expanding the metabolic capabilities of bacteria and provide new options for improved biotreatment of chloronitrobenzene‐contaminated sites. PMID:21261918</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PMB....56N.153M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PMB....56N.153M"><span>An octahedral shear <span class="hlt">strain</span>-based measure of SNR for 3D MR elastography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McGarry, M. D. J.; Van Houten, E. E. W.; Perriñez, P. R.; Pattison, A. J.; Weaver, J. B.; Paulsen, K. D.</p> <p>2011-07-01</p> <p>A signal-to-noise ratio (SNR) measure based on the octahedral shear <span class="hlt">strain</span> (the maximum shear <span class="hlt">strain</span> in any plane for a 3D state of <span class="hlt">strain</span>) is presented for magnetic resonance elastography (MRE), where motion-based SNR measures are commonly used. The shear <span class="hlt">strain</span>, γ, is directly related to the shear modulus, μ, through the definition of shear stress, τ = μγ. Therefore, noise in the <span class="hlt">strain</span> is the important factor in determining the quality of motion data, rather than the noise in the motion. Motion and <span class="hlt">strain</span> SNR measures were found to be correlated for MRE of gelatin phantoms and the human breast. Analysis of the stiffness distributions of phantoms reconstructed from the measured motion data revealed a threshold for both <span class="hlt">strain</span> and motion SNR where MRE stiffness estimates match independent mechanical testing. MRE of the feline brain showed significantly less correlation between the two SNR measures. The <span class="hlt">strain</span> SNR measure had a threshold above which the reconstructed stiffness values were consistent between cases, whereas the motion SNR measure did not provide a useful threshold, primarily <span class="hlt">due</span> to rigid body motion effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=276780','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=276780"><span>Effects of Mitomycin C and Thymidine Deprivation on Lysogenic and Sensitive <span class="hlt">Strains</span> of Bacillus megaterium1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Maisch, W. F.; Wachsman, J. T.</p> <p>1967-01-01</p> <p>A triple auxotroph of Bacillus megaterium <span class="hlt">strain</span> KM was lysogenized with a phage suspension from B. megaterium 899a. The lysogenic and phage-sensitive derivatives of KM were found to die at the same exponential rate during thymineless incubation, despite the fact that the lysogenic <span class="hlt">strain</span> became induced. The lysogenic <span class="hlt">strain</span> was also induced by mitomycin C, and died at an exponential rate which was approximately twice that of the sensitive <span class="hlt">strain</span>. With both <span class="hlt">strains</span>, the lethality of mitomycin C was the same in the presence and absence of thymidine; thymidine was required for maximal phage production. Mitomycin C preferentially inhibited deoxyribonucleic acid (DNA) synthesis of both <span class="hlt">strains</span> for the first 60 min. The (DNA) synthetic ability of the lysogenic <span class="hlt">strain</span> was subsequently restored, <span class="hlt">due</span> to phage production. Since there was no evidence that sensitive <span class="hlt">strains</span> of KM contained other inducible elements (prophage or probacteriocins), it is concluded that both thymineless death and mitomycin C death can occur via mechanisms not involving induction. PMID:4963773</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3172714','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3172714"><span>An Octahedral Shear <span class="hlt">Strain</span> Based measure of SNR for 3D MR Elastography</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McGarry, MDJ; Van Houten, EEW; Perriñez, PR; Pattison, AJ; Weaver, JB; Paulsen, KD</p> <p>2011-01-01</p> <p>A signal to noise ratio (SNR) measure based on the octahedral shear <span class="hlt">strain</span> (the maximum shear <span class="hlt">strain</span> in any plane for a 3D state of <span class="hlt">strain</span>) is presented for MR elastography, where motion-based SNR measures are commonly used. The shear <span class="hlt">strain</span>, γ, is directly related to the shear modulus, μ, through the definition of shear stress, τ = μγ. Therefore, noise in the <span class="hlt">strain</span> is the important factor in determining the quality of motion data, rather than the noise in the motion. Motion and <span class="hlt">strain</span> SNR measures were found to be correlated for MRE of gelatin phantoms and human breast. Analysis of the stiffness distributions of phantoms reconstructed from the measured motion data revealed a threshold for both <span class="hlt">strain</span> and motion SNR where MRE stiffness estimates match independent mechanical testing. MRE of the feline brain showed significantly less correlation between the two SNR measures. The <span class="hlt">strain</span> SNR measure had a threshold above which the reconstructed stiffness values were consistent between cases, whereas the motion SNR measure did not provide a useful threshold, primarily <span class="hlt">due</span> to rigid body motion effects. PMID:21654044</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21654044','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21654044"><span>An octahedral shear <span class="hlt">strain</span>-based measure of SNR for 3D MR elastography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McGarry, M D J; Van Houten, E E W; Perriñez, P R; Pattison, A J; Weaver, J B; Paulsen, K D</p> <p>2011-07-07</p> <p>A signal-to-noise ratio (SNR) measure based on the octahedral shear <span class="hlt">strain</span> (the maximum shear <span class="hlt">strain</span> in any plane for a 3D state of <span class="hlt">strain</span>) is presented for magnetic resonance elastography (MRE), where motion-based SNR measures are commonly used. The shear <span class="hlt">strain</span>, γ, is directly related to the shear modulus, μ, through the definition of shear stress, τ = μγ. Therefore, noise in the <span class="hlt">strain</span> is the important factor in determining the quality of motion data, rather than the noise in the motion. Motion and <span class="hlt">strain</span> SNR measures were found to be correlated for MRE of gelatin phantoms and the human breast. Analysis of the stiffness distributions of phantoms reconstructed from the measured motion data revealed a threshold for both <span class="hlt">strain</span> and motion SNR where MRE stiffness estimates match independent mechanical testing. MRE of the feline brain showed significantly less correlation between the two SNR measures. The <span class="hlt">strain</span> SNR measure had a threshold above which the reconstructed stiffness values were consistent between cases, whereas the motion SNR measure did not provide a useful threshold, primarily <span class="hlt">due</span> to rigid body motion effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4177381','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4177381"><span>Uniaxial <span class="hlt">strain</span>-induced mechanical and electronic property modulation of silicene</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>We perform first-principles calculations of mechanical and electronic properties of silicene under uniaxial <span class="hlt">strains</span>. Poisson's ratio and the rigidity of silicene show strong chirality dependence under large uniaxial <span class="hlt">strains</span>. The ultimate <span class="hlt">strains</span> of silicene with uniaxial <span class="hlt">strain</span> are smaller than those with biaxial <span class="hlt">strain</span>. We find that uniaxial <span class="hlt">strains</span> induce Dirac point deviation from the high-symmetry points in the Brillouin zone and semimetal-metal transitions. Therefore, no bandgap opens under the uniaxial <span class="hlt">strain</span>. <span class="hlt">Due</span> to its peculiar structure and variable sp3/sp2 ratio of the chemical bond, the deviation directions of Dirac points from the high-symmetry points in the Brillouin zone and variation of Fermi velocities of silicene exhibit significant difference from those of graphene. Fermi velocities show strong anisotropy with respect to the wave vector directions and change slightly before the semimetal-metal transition. We also find that the work function of silicene increases monotonously with the increasing uniaxial <span class="hlt">strains</span>. PACS numbers 61.46.-w; 62.20.D-; 73.22.Dj PMID:25276108</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4005521','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4005521"><span>Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi <span class="hlt">strains</span> in Beagle dogs</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nogueira-Paiva, Nívia Carolina; Fonseca, Kátia da Silva; Vieira, Paula Melo de Abreu; Diniz, Lívia Figueiredo; Caldas, Ivo Santana; de Moura, Sandra Aparecida Lima; Veloso, Vanja Maria; Guedes, Paulo Marcos da Matta; Tafuri, Washington Luiz; Bahia, Maria Terezinha; Carneiro, Cláudia Martins</p> <p>2013-01-01</p> <p>Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi <span class="hlt">strains</span> and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both <span class="hlt">strains</span> infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly <span class="hlt">due</span> to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both <span class="hlt">strains</span>, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y <span class="hlt">strain</span>, while animals infected with the Be-78 <span class="hlt">strain</span> showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both <span class="hlt">strains</span> cause lesions in the digestive tract, the Y <span class="hlt">strain</span> is associated with early control of the lesion, while the Be-78 <span class="hlt">strain</span> results in progressive gut lesions in this model. PMID:24271001</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4632108','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4632108"><span>Flexible CNT-array double helices <span class="hlt">Strain</span> Sensor with high stretchability for Motion Capture</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Cheng; Cui, Ya-Long; Tian, Gui-Li; Shu, Yi; Wang, Xue-Feng; Tian, He; Yang, Yi; Wei, Fei; Ren, Tian-Ling</p> <p>2015-01-01</p> <p>Motion capture is attracting more and more attention <span class="hlt">due</span> to its potential wide applications in various fields. However, traditional methods for motion capture still have weakness such as high cost and space consuming. Based on these considerations, a flexible, highly stretchable <span class="hlt">strain</span> sensor with high gauge factor for motion capture is fabricated with carbon nanotube (CNT) array double helices as the main building block. Ascribed to the unique flexible double helical CNT-array matrix, the <span class="hlt">strain</span> sensor is able to measure <span class="hlt">strain</span> up to 410%, with low hysteresis. Moreover, a demonstration of using this <span class="hlt">strain</span> sensor for capture hand motion and to control a mechanical hand in real time is also achieved. A model based on finite difference method is also made to help understand the mechanism of the <span class="hlt">strain</span> sensors. Our work demonstrates that <span class="hlt">strain</span> sensors can measure very large <span class="hlt">strain</span> while maintaining high sensitivity, and the motion capture based on this <span class="hlt">strain</span> sensor is expected to be less expensive, more convenient and accessible. PMID:26530904</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27586990','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27586990"><span>[Tinea corporis <span class="hlt">due</span> to the rare geophilic dermatophyte Microsporum praecox].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nenoff, P; Overbeck, C; Uhrlaß, S; Krüger, C; Gräser, Y</p> <p>2016-09-01</p> <p>A 10-year-old girl suffered from tinea corporis with erythematosquamous and centrifugal growing, sparse itching lesions of her right lower arm. Fluorescence optical Blankophor® preparation from skin scrapings revealed fungal hyphae. On Sabouraud's dextrose agar, the fast growing dermatophyte formed flat, peripheral radiating and convolved colonies with white, slightly yellowish to beige brown stained granular and powdery surface. The reverse side of the colonies was smooth with luminous yellow colour. Microscopically, an attitude of thin-walled spindle-shaped and echinulate (with small spins) and lanceolate macroconidia appeared. The small based macroconidia are raised in the middle and end part, however, pointy at the end ("spearhead"). Three to six or seven across septae are formed. The small piriform microconidia had an orthotropic arrangement. Chlamydospores were also formed. Urease activity was positive. Macromorphologically, Trichophyton (T.) interdigitale (formerly T. mentagrophytes) was suspected. <span class="hlt">Due</span> to the shape of macroconidia, Microsporum (M.) gypseum and M. fulvum were also considered as possible species identification. Direct uniplex-PCR-EIA of the <span class="hlt">strains</span> revealed negative results for T. rubrum, T. interdigitale, T. anamorph of Arthroderma benhamiae and M. canis. Sequencing analysis of the ribosomal ITS-region (18 S rRNA, ITS1, 5.8 S rRNA, ITS2, 28 S rRNA) and of the translation elongation factor 1‑alpha (tef-1-alpha) gene revealed the dermatophyte species M. praecox. Topical treatment was done using ciclopiroxolamine cream. M. praecox represents a geophilic dermatophyte, morphologically resembling M. gypseum. Horses are often the source of infection. In humans, M. praecox causes tinea corporis and tinea capitis. For oral treatment of dermatomycosis <span class="hlt">due</span> to M. praecox, griseofulvin and terbinafine can be used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7634E..0FZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7634E..0FZ"><span>Temperature independent <span class="hlt">strain</span> sensor based on intensity measurement using a highly birefringent photonic crystal fiber loop mirror</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Chun-Liu; Dong, Xinyong; Zhang, Shuqin; Jin, Wei</p> <p>2009-11-01</p> <p>A fiber-optic <span class="hlt">strain</span> sensor is demonstrated by using a short length of highly birefringent photonic crystal fiber (PCF) as the sensing element inserted in a fiber loop mirror (FLM). <span class="hlt">Due</span> to the ultralow thermal sensitivity of the PCF, the proposed <span class="hlt">strain</span> sensor is inherently insensitive to temperature. When a DFB laser passes through the FLM, the output power will only be affected by the transmission spectral change of the FLM caused by the <span class="hlt">strain</span> applied on the PCF. Based on intensity measurement, an optical power meter is adequate to deduce the <span class="hlt">strain</span> information and an expensive optical spectrum analyzer (OSA) would not be needed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24518385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24518385"><span>The many shades of prion <span class="hlt">strain</span> adaptation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baskakov, Ilia V</p> <p>2014-01-01</p> <p>In several recent studies transmissible prion disease was induced in animals by inoculation with recombinant prion protein amyloid fibrils produced in vitro. Serial transmission of amyloid fibrils gave rise to a new class of prion <span class="hlt">strains</span> of synthetic origin. Gradual transformation of disease phenotypes and PrP(Sc) properties was observed during serial transmission of synthetic prions, a process that resembled the phenomenon of prion <span class="hlt">strain</span> adaptation. The current article discusses the remarkable parallels between phenomena of prion <span class="hlt">strain</span> adaptation that accompanies cross-species transmission and the evolution of synthetic prions occurring within the same host. Two alternative mechanisms underlying prion <span class="hlt">strain</span> adaptation and synthetic <span class="hlt">strain</span> evolution are discussed. The current article highlights the complexity of the prion transmission barrier and <span class="hlt">strain</span> adaptation and proposes that the phenomenon of prion adaptation is more common than previously thought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3824...30W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3824...30W"><span>Miniaturization of speckle interferometry for rapid <span class="hlt">strain</span> analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wegner, Ronny; Ettemeyer, Andreas</p> <p>1999-09-01</p> <p>Today's industry demands high-performance components meeting toughest mechanical features and ultimate safety standards. Especially in automotive and aircraft industry the development focuses on tailor-made design and solutions according to customer specifications. To reconcile economy, light-weight construction has become a key issue. Many companies are looking for new advanced <span class="hlt">strain</span>/stress analysis techniques to improve cost efficiency and the limitations of classical methods. Detection of weak points and fatigue tests are carried out mainly with <span class="hlt">strain</span> gauges which need careful application and experience. ESPI (electronic speckle pattern interferometry) allows a rapid, full field and 3D-measurement without contact. This paper presents the principle and application of a new miniaturized laser optical sensor combining contour and deformation measurement. In its basic employment ESPI is an interferometric method measuring deformations at modern working materials with high accuracy. Here also a module for contouring was developed and integrated into a single interferometer. Therefore even at complex components it is possible to measure and display <span class="hlt">strain</span>-fields and -gradients with respect to the underlying contour. The new sensor is a unique device for flexible <span class="hlt">strain</span>-analysis at welded-materials, extrusions, engines, car-bodies, etc. Without preparation and <span class="hlt">due</span> to the full field and 3D- measurement 'hot spots' are shown, reducing the testing procedure and increasing the reliability of the complex component testing significantly. In this paper the recent development of a miniaturized ESPI-interferometer for <span class="hlt">strain</span> and stress measurement is described. Advanced features according to classical techniques are specified and new applications in material and component testing are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25919624','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25919624"><span>Investigating antimicrobial activity in Rheinheimera sp. <span class="hlt">due</span> to hydrogen peroxide generated by l-lysine oxidase activity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Wen Ming; Lin, Chang Yi; Sheu, Shih Yi</p> <p>2010-05-05</p> <p>A greenish yellow pigmented bacterial <span class="hlt">strain</span>, designated GR5, was recently isolated from a freshwater culture pond for a soft-shell turtle. Phylogenetic analyses based on 16S rRNA gene sequences indicate that <span class="hlt">strain</span> GR5 belongs to the genus Rheinheimera and its only closest neighbor is the type <span class="hlt">strain</span> of Rheinheimera texasensis (98.2%). Based on the antibiogram assay, <span class="hlt">strain</span> GR5 possesses a broad spectrum of antimicrobial activity including Gram-positive and Gram-negative bacteria, yeast, algae, and <span class="hlt">strain</span> GR5 itself. <span class="hlt">Strain</span> GR5 can synthesize a macromolecule with antimicrobial activity <span class="hlt">due</span> to the generation of hydrogen peroxide and this antimicrobial effect can be inhibited by catalase. This antimicrobial activity is active only in complex culture media or chemically defined culture media containing l-lysine. This antimicrobial macromolecule in <span class="hlt">strain</span> GR5 is shown to be a monomeric protein with a molecular mass of 71kDa and isoelectric point of approximately 3.68. Liquid chromatography-tandem mass spectrometry analyses reveal close similarity of a 19-amino acid fragment derived from this protein to the antibacterial protein, AlpP from the marine bacterium Pseudoalteromonas tunicata D2, and to the antibacterial protein, marinocine, from the marine bacterium Marinomonas mediterranea. This study explores the nature of antimicrobial macromolecule such as l-lysine oxidase. This is the first report on a freshwater bacterium producing antimicrobial activity by generating hydrogen peroxide through its enzymatic activity of l-lysine oxidase.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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