WorldWideScience

Sample records for stress concentration due

  1. Stress distributions due to hydrogen concentrations in electrochemically charged and aged austenitic stainless steel

    International Nuclear Information System (INIS)

    Rozenak, P.; Loew, A.

    2008-01-01

    As a result of hydrogen concentration gradients in type austenitic stainless steels, formed during electrochemical charging and followed by hydrogen loss during aging, at room temperature, surface stresses were developed. These stresses were measured by X-ray technique and the crack formation thus induced could be studied using equilibrium stress equations. After various electrochemical charging and aging times, X-ray diffraction patterns obtained from samples indicated that the reflected and broadened diffraction peaks are the result of the formation of a non-uniform but continuous solid solution in the austenitic matrix. Since both hydrogen penetrations during charging and hydrogen release during aging are diffusion controlled processes and huge hydrogen concentration gradients in the thin surface layer, at depths comparable with the depth of X-ray penetration, are observed. The non-uniform hydrogen concentration in the austenitic matrix, results to the non-uniform expansion of the atomic microstructure and latter inevitably leads to the development of internal stresses. The internal stresses development formulae's are very similar to those relating to non-uniform heating of the materials, where thermal stresses appear due to non-uniform expansion or contraction. The relevant well developed theory is applicable in our case of non-uniform hydrogen concentrations in a solid solution of electrochemically charged and aged austenitic matrix. A few cracks were present on the surface after some minutes of electrochemical charging and the severity of cracking increased as hydrogen was lost during subsequent aging. This is consistent with the expectation of high compressive stresses in the bulk of the specimen during charging and high tensile surface stresses (at the level of 1 x 10 11 Pa) during the aging process. These stresses can induce the formation of surface cracks during the aging process after electrochemical charging in the AISI 316 stainless steel

  2. Stress concentration at notches

    CERN Document Server

    Savruk, Mykhaylo P

    2017-01-01

    This book compiles solutions of linear theory of elasticity problems for isotropic and anisotropic bodies with sharp and rounded notches. It contains an overview of established and recent achievements, and presents the authors’ original solutions in the field considered with extensive discussion. The volume demonstrates through numerous, useful examples the effectiveness of singular integral equations for obtaining exact solutions of boundary problems of the theory of elasticity for bodies with cracks and notches. Incorporating analytical and numerical solutions of the problems of stress concentrations in solid bodies with crack-like defects, this volume is ideal for scientists and PhD students dealing with the problems of theory of elasticity and fracture mechanics. Stands as a modern and extensive compendium of solutions to the problems of linear theory of elasticity of isotropic and anisotropic bodies with sharp and rounded notches; Adopts a highly reader-friendly layout of tables, charts, approximation ...

  3. Concentration changes due to cathodic protection

    NARCIS (Netherlands)

    Gellings, P.J.

    1978-01-01

    By solving the appropriate diffusion equations the concentration changes are calculated in the environment of underground structures protected cathodically. It is shown that these changes are negligible under all practical circumstances.

  4. Stress concentration effects in high pressure components

    International Nuclear Information System (INIS)

    Aller, J.E.

    1990-01-01

    This paper examines the stress concentration effects of sideholes in thick walled, high pressure cylinders. It has been shown that the theoretical stress concentration factor at the intersection of a small crossbore in a closed end, thick walled cylinder varies between 3.0 and 4.0. Tests have shown that this effect can be greatly reduced in practice by carefully radiusing the bore intersection and autofrettaging the cylinder. It has also been shown that the minimum stress concentration factor occurs when the main bore and sidehole or crossbore have the same diameter, and the radius of the intersection is approximately equal to the sidehole radius. When the bore and sidehole intersection angle decreases from 90 degrees, the stress concentration factor increases significantly. Knowledge of these fundamental relationships can be used in maintaining, as well ad designing, high pressure equipment

  5. Stress Concentration around Holes in Anistropic Sheets

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    The formulation of stress concentration problems of plane anisotropic elasticity in terms of integral equations is discussed. First the singular solutions of a concentrated force and a dislocation are formulated so that they remain valid in the case of double roots. The distribution of singularit...

  6. Optimization of bolt thread stress concentrations

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    Designs of threaded fasteners are controlled by different standards, and the number of different thread definitions is large. The most commonly used thread is probably the metric ISO thread, and this design is therefore used in the present paper. Thread root design controls the stress concentration...... are found in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool....

  7. Existence of black holes due to concentration of angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Khuri, Marcus A. [Department of Mathematics, Stony Brook University,Stony Brook, NY 11794 (United States)

    2015-06-29

    We present a general sufficient condition for the formation of black holes due to concentration of angular momentum. This is expressed in the form of a universal inequality, relating the size and angular momentum of bodies, and is proven in the context of axisymmetric initial data sets for the Einstein equations which satisfy an appropriate energy condition. A brief comparison is also made with more traditional black hole existence criteria based on concentration of mass.

  8. PREDICTION OF STRESS CONCENTRATION FACTORS IN

    African Journals Online (AJOL)

    ES OBE

    consider the effect of brace spacing on strengths of tubular K joints without consideration of same effect on square section K Joints. This lack of studies design strengths of gapped square section K joints makes availability of information on stress concentration factors in same joints scarce. However, information on 'Hot Spot' ...

  9. Stress concentration factors for pressurized elliptic crossbores in blocks

    International Nuclear Information System (INIS)

    Badr, Elie A.

    2006-01-01

    Intersecting bore geometries are used in a number of industrial applications including heavy-walled pressure vessels containing oil holes for lubrication, ports for valves and fluid ends of reciprocating pumps. The bore intersection location is a stress concentration point where the maximum hoop stress can be many times the fluid pressure in the bores. Intersecting circular holes in heavy-walled cylinders and rectangular blocks have been extensively investigated. Specifically, stress/pressure concentration curves for intersecting circular bores in rectangular blocks were presented by Sorem et al. [Sorem JR, Shadley JR, Tipton SM. Design curves for maximum stresses in blocks containing pressurized bore intersections. ASME J Mech Des 1990; 113: 427-31.]. However, stress/pressure concentrations due to intersecting elliptic bores have not been broadly investigated. With the availability of computer numerical control (CNC) machinery, bores with elliptic crosssection can be produced with relative ease. In this paper, hoop stress concentration ratios are developed for elliptic crossbores in rectangular blocks. Results indicate that introducing elliptic crossbores, rather than circular ones, significantly reduces the hoop stress concentration factor at the crossbore intersection. Also, the presence of intersecting crossbores has a major effect on the fatigue life of pressure vessels [Badr EA, Sorem JR, Jr Tipton SM. Evaluation of the autofrettage effect on fatigue lives of steel blocks with crossbores using a statistical and a strain-based method. ASTM J Test Eval 2000; 28: 181-8.] and the reduction of hoop stress concentration is expected to enhance the fatigue life of pressure vessels containing crossbores

  10. Theoretical basis for convective invigoration due to increased aerosol concentration

    Directory of Open Access Journals (Sweden)

    Z. J. Lebo

    2011-06-01

    Full Text Available The potential effects of increased aerosol loading on the development of deep convective clouds and resulting precipitation amounts are studied by employing the Weather Research and Forecasting (WRF model as a detailed high-resolution cloud resolving model (CRM with both detailed bulk and bin microphysics schemes. Both models include a physically-based activation scheme that incorporates a size-resolved aerosol population. We demonstrate that the aerosol-induced effect is controlled by the balance between latent heating and the increase in condensed water aloft, each having opposing effects on buoyancy. It is also shown that under polluted conditions, increases in the CCN number concentration reduce the cumulative precipitation due to the competition between the sedimentation and evaporation/sublimation timescales. The effect of an increase in the IN number concentration on the dynamics of deep convective clouds is small and the resulting decrease in domain-averaged cumulative precipitation is shown not to be statistically significant, but may act to suppress precipitation. It is also shown that even in the presence of a decrease in the domain-averaged cumulative precipitation, an increase in the precipitation variance, or in other words, andincrease in rainfall intensity, may be expected in more polluted environments, especially in moist environments.

    A significant difference exists between the predictions based on the bin and bulk microphysics schemes of precipitation and the influence of aerosol perturbations on updraft velocity within the convective core. The bulk microphysics scheme shows little change in the latent heating rates due to an increase in the CCN number concentration, while the bin microphysics scheme demonstrates significant increases in the latent heating aloft with increasing CCN number concentration. This suggests that even a detailed two-bulk microphysics scheme, coupled to a detailed activation scheme, may not be

  11. Crack initiation criteria for singular stress concentrations Part I: A universal assessment of singular stress concentrations

    Czech Academy of Sciences Publication Activity Database

    Knésl, Zdeněk; Klusák, Jan; Náhlík, Luboš

    2007-01-01

    Roč. 14, č. 6 (2007), s. 399-408 ISSN 1802-1484 R&D Projects: GA ČR(CZ) GA101/05/0320; GA ČR GA101/05/0227 Institutional research plan: CEZ:AV0Z20410507 Keywords : fracture mechanics * stability criteria * singular stress concentrations * crack initiation * critical stress Subject RIV: JL - Materials Fatigue, Friction Mechanics

  12. Evaluation of stress intensity factors due to welding residual stresses for circumferential cracked pipes

    International Nuclear Information System (INIS)

    Oh, Chang-Young; Kim, Yun-Jae; Oh, Young-Jin; Kim, Jong-Sung; Song, Tae-Kwang; Kim, Yong-Beum

    2013-01-01

    To investigate the applicability of existing methods to estimate stress intensity factors due to welding residual stresses, comparisons with finite element (FE) solutions are made for two types of generic welding residual stress profiles, generated by simulating repair welds. It is found that fitting residual stresses over the crack depth using third-order polynomials gives good estimates of stress intensity factors but fitting over the entire thickness can result in inaccurate estimates even with fourth-order polynomials. Noting that welding residual stresses are often determined from FE analyses, linearization of residual stresses to estimate stress intensity factors is proposed. Comparison with FE solutions shows good agreements. -- Highlights: ► Applicability of K estimation methods is investigated for welding residual stresses. ► Two types of generic residual stress profiles with repair welds are considered. ► Fitting residual stresses over the crack depth gives good estimates of K. ► A method to estimate K by linearising residual stress profiles is proposed

  13. Heat exchanger nozzle stresses due to pipe vibration

    International Nuclear Information System (INIS)

    Wolgemuth, G.A.

    1983-01-01

    A large diameter pipe in a heavy water production plant was excited into a low frequency vibration due to void collapse of the pipe contents at a sharp vertical drop in the pipe run. Fears that this vibration would fatigue the inlet nozzle to the heat exchanger prompted the introduction of a flow of cold water into the pipe to prevent the two-phase flow from developing but at the cost of reduced heat exchanger efficiency. An investigation was carried out to determine the stress levels in the nozzle with the quenching flow off and suggest means of reducing them if excessive. A finite element dynamic simulation of the pipe run was performed to determine the likely mode shapes. This information was used to optimize the placement of velocity probes on the pipe. Field measurements of vibration were taken for several operating conditions. This data was analyzed and the results used to refine the support stiffness used in the finite element simulation. The finite element model was then used to predict the nozzle forces and moments. In turn this data was used to determine the local stresses in the nozzle. The ASME Section III code was used to determine the allowable fully reversing stresses for the unit in question. It was found that the endurance limit of 83 MPa was exceeded in the analysis only when using the most conservative estimates for each uncertainty. It was recommended that if the safety factor was not deemed high enough, the nozzle should be built up with a reinforcing pad no thicker than 12 mm

  14. Projecting future summer mortality due to ambient ozone concentration and temperature changes

    Science.gov (United States)

    Lee, Jae Young; Lee, Soo Hyun; Hong, Sung-Chul; Kim, Ho

    2017-05-01

    Climate change is known to affect the human health both directly by increased heat stress and indirectly by altering environments, particularly by altering the rate of ambient ozone formation in the atmosphere. Thus, the risks of climate change may be underestimated if the effects of both future temperature and ambient ozone concentrations are not considered. This study presents a projection of future summer non-accidental mortality in seven major cities of South Korea during the 2020s (2016-2025) and 2050s (2046-2055) considering changes in temperature and ozone concentration, which were predicted by using the HadGEM3-RA model and Integrated Climate and Air Quality Modeling System, respectively. Four Representative Concentration Pathway (RCP) scenarios (RCP 2.6, 4.5, 6.0, and 8.5) were considered. The result shows that non-accidental summer mortality will increase by 0.5%, 0.0%, 0.4%, and 0.4% in the 2020s, 1.9%, 1.5%, 1.2%, and 4.4% in the 2050s due to temperature change compared to the baseline mortality during 2001-2010, under RCP 2.6, 4.5, 6.0, and 8.5, respectively, whereas the mortality will increase by 0.0%, 0.5%, 0.0%, and 0.5% in the 2020s, and 0.2%, 0.2%, 0.4%, and 0.6% in the 2050s due to ozone concentration change. The projection result shows that the future summer morality in South Korea is increased due to changes in both temperature and ozone, and the magnitude of ozone-related increase is much smaller than that of temperature-related increase, especially in the 2050s.

  15. Stress analysis in curved composites due to thermal loading

    Science.gov (United States)

    Polk, Jared Cornelius

    Many structures in aircraft, cars, trucks, ships, machines, tools, bridges, and buildings, consist of curved sections. These sections vary from straight line segments that have curvature at either one or both ends, segments with compound curvatures, segments with two mutually perpendicular curvatures or Gaussian curvatures, and segments with a simple curvature. With the advancements made in multi-purpose composites over the past 60 years, composites slowly but steadily have been appearing in these various vehicles, compound structures, and buildings. These composite sections provide added benefits over isotropic, polymeric, and ceramic materials by generally having a higher specific strength, higher specific stiffnesses, longer fatigue life, lower density, possibilities in reduction of life cycle and/or acquisition cost, and greater adaptability to intended function of structure via material composition and geometry. To be able to design and manufacture a safe composite laminate or structure, it is imperative that the stress distributions, their causes, and effects are thoroughly understood in order to successfully accomplish mission objectives and manufacture a safe and reliable composite. The objective of the thesis work is to expand upon the knowledge of simply curved composite structures by exploring and ascertaining all pertinent parameters, phenomenon, and trends in stress variations in curved laminates due to thermal loading. The simply curved composites consist of composites with one radius of curvature throughout the span of the specimen about only one axis. Analytical beam theory, classical lamination theory, and finite element analysis were used to ascertain stress variations in a flat, isotropic beam. An analytical method was developed to ascertain the stress variations in an isotropic, simply curved beam under thermal loading that is under both free-free and fixed-fixed constraint conditions. This is the first such solution to Author's best knowledge

  16. Suggested benchmarks for shape optimization for minimum stress concentration

    DEFF Research Database (Denmark)

    Pedersen, Pauli

    2008-01-01

    Shape optimization for minimum stress concentration is vital, important, and difficult. New formulations and numerical procedures imply the need for good benchmarks. The available analytical shape solutions rely on assumptions that are seldom satisfied, so here, we suggest alternative benchmarks...

  17. Pipe cracking due to thermal stresses produced by valve opening

    International Nuclear Information System (INIS)

    Sanchez Sarmiento, G.

    1982-01-01

    The thermal stresses produced in a tube whose internal surface is abrupt cooled during a valve opening so that the water volume increases linearly with time are studied. A general solution for these stresses and its stress intensity factors in terms of non-dimensional parameters is presented. (E.G.) [pt

  18. Stress Concentration Factor and Stress Intensity Factor with U-notch and Crack in the Beam

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Bo Seong; Lee, Kwang Ho [Kyungpook National Univ., Daegu (Korea, Republic of)

    2016-05-15

    The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and photoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1-2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used, where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length α(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

  19. Transient thermal stresses in composite hollow circular cylinder due to partial heat generation

    International Nuclear Information System (INIS)

    Goshima, Takahito; Miyao, Kaju

    1979-01-01

    Clad materials are adopted for the machines and structures used in contact with high temperature, corrosive atmosphere in view of their strength and economy. Large thermal stress sometimes arises in clad cylinders due to uneaven temperature field and the difference in linear thermal expansion. Vessels are often heated uneavenly, and shearing stress occurs, which is not observed in uniform heating. In this study, infinitely long, concentric cylinders of two layers were analyzed, when the internal heat changing in stepped state is generated in cylindrical form. The unsteady thermal stress occurred was determined, using thermo-elastic potential and stress functions, and assuming the thermal properties and elastic modulus of materials as constant regardless of the temperature. Laplace transformation was used, and the basic equations for thermo-elastic displacement were employed as the basis of calculation. The analysis of the temperature distribution and stress is explained. Numerical calculation was carried out on the example of an internal cylinder of SUS 304 stainless steel and an external cylinder of mild steel. The maximum shearing stress occurred in the direction of 40 deg from the heat source, and was affected largely by the position of heat generation. The effect became remarkable as time elapsed. (Kako, I.)

  20. Plain bearing stresses due to forming and oil film pressure

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Veliz, A; Reed, P A S; Syngellakis, S [University of Southampton, School of Engineering Sciences, Southampton SO17 1BJ (United Kingdom); Wang, D; Wahdy, N; Merritt, D, E-mail: allan.burke@itesm.m [MAHLE Engine Systems UK Ltd, 2 Central park Drive, Rugby CV23 0WE (United Kingdom)

    2009-08-01

    This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

  1. Plain bearing stresses due to forming and oil film pressure

    International Nuclear Information System (INIS)

    Burke-Veliz, A; Reed, P A S; Syngellakis, S; Wang, D; Wahdy, N; Merritt, D

    2009-01-01

    This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

  2. Post-traumatic stress disorder due to childbirth: the aftermath.

    Science.gov (United States)

    Beck, Cheryl Tatano

    2004-01-01

    Childbirth qualifies as an extreme traumatic stressor that can result in post-traumatic stress disorder. The reported prevalence of post-traumatic stress disorder after childbirth ranges from 1.5% to 6%. The aim of this phenomenologic study was to describe the essence of mothers' experiences of post-traumatic stress disorder after childbirth. The qualitative research design used for this study was descriptive phenomenology. The main recruitment approach was via the Internet through the help of Trauma and Birth Stress, a charitable trust in New Zealand. Purposive sampling was used and resulted in 38 mothers participating from the countries of New Zealand, the United States, Australia, and the United Kingdom. The participants were asked to describe their experiences with post-traumatic stress disorder after childbirth. Their stories were analyzed using Colaizzi's method of data analysis. Mothers with post-traumatic stress disorder attributable to childbirth struggle to survive each day while battling terrifying nightmares and flashbacks of the birth, anger, anxiety, depression, and painful isolation from the world of motherhood. This glimpse into the lives of mothers with post-traumatic stress disorder attributable to childbirth provides an impetus to increase research efforts in this neglected area.

  3. Imaging shear stress distribution and evaluating the stress concentration factor of the human eye

    Science.gov (United States)

    Joseph Antony, S.

    2015-03-01

    Healthy eyes are vital for a better quality of human life. Historically, for man-made materials, scientists and engineers use stress concentration factors to characterise the effects of structural non-homogeneities on their mechanical strength. However, such information is scarce for the human eye. Here we present the shear stress distribution profiles of a healthy human cornea surface in vivo using photo-stress analysis tomography, which is a non-intrusive and non-X-ray based method. The corneal birefringent retardation measured here is comparable to that of previous studies. Using this, we derive eye stress concentration factors and the directional alignment of major principal stress on the surface of the cornea. Similar to thermometers being used for monitoring the general health in humans, this report provides a foundation to characterise the shear stress carrying capacity of the cornea, and a potential bench mark for validating theoretical modelling of stresses in the human eye in future.

  4. Magnetostriction of a sphere: stress development during magnetization and residual stresses due to the remanent field

    Science.gov (United States)

    Reich, Felix A.; Rickert, Wilhelm; Stahn, Oliver; Müller, Wolfgang H.

    2017-03-01

    Based on the principles of rational continuum mechanics and electrodynamics (see Truesdell and Toupin in Handbuch der Physik, Springer, Berlin, 1960 or Kovetz in Electromagnetic theory, Oxford University Press, Oxford, 2000), we present closed-form solutions for the mechanical displacements and stresses of two different magnets. Both magnets are initially of spherical shape. The first (hard) magnet is uniformly magnetized and deforms due to the field induced by the magnetization. In the second problem of a (soft) linear-magnetic sphere, the deformation is caused by an applied external field, giving rise to magnetization. Both problems can be used for modeling parts of general magnetization processes. We will address the similarities between both settings in context with the solutions for the stresses and displacements. In both problems, the volumetric Lorentz force density vanishes. However, a Lorentz surface traction is present. This traction is determined from the magnetic flux density. Since the obtained displacements and stresses are small in magnitude, we may use Hooke's law with a small-strain approximation, resulting in the Lamé- Navier equations of linear elasticity theory. If gravity is neglected and azimuthal symmetry is assumed, these equations can be solved in terms of a series. This has been done by Hiramatsu and Oka (Int J Rock Mech Min Sci Geomech Abstr 3(2):89-90, 1966) before. We make use of their series solution for the displacements and the stresses and expand the Lorentz tractions of the analyzed problems suitably in order to find the expansion coefficients. The resulting algebraic system yields finite numbers of nonvanishing coefficients. Finally, the resulting stresses, displacements, principal strains and the Lorentz tractions are illustrated and discussed.

  5. Effects of high concentration of chromium stress on physiological ...

    African Journals Online (AJOL)

    We studied the effects of high concentration of chromium (Cr) stress on physiological and biochemical characters and accumulation of Cr in Pingyang Tezao tea [Camellia sinensis (L) O. Kutze 'Pingyangtezao'] through a pot experiment. The results show that the indicators of photosynthesis were all suppressed with ...

  6. Creep cavitation in the neighborhood of stress concentrations

    International Nuclear Information System (INIS)

    Liu, T.S.; Delph, T.J.; Fields, R.J.

    1983-01-01

    The results of several experiments into the formation and distribution of creep cavitation in the neighborhood of stress concentrations is reported. Of particular interest is the use of an image analyzing computer to construct quantitative maps of cavity sizes and distributions. Comparisons are drawn in one case with the results of a finite element simulation, and some degree of overall agreement is noted. (orig.)

  7. L5 radiculopathy due to sacral stress fracture

    International Nuclear Information System (INIS)

    Aylwin, Anthony; Saifuddin, Asif; Tucker, Stuart

    2003-01-01

    We report the case of a 70-year-old man who presented with a history of left buttock pain with radiation into the left leg in an L5 distribution. MRI of the lumbar spine revealed a left sacral stress fracture with periosteal reaction involving the left L5 nerve root anterior to the sacral ala. With spontaneous healing of the fracture, the patient's symptoms resolved completely. (orig.)

  8. Modified Weibull theory and stress-concentration factors of polycrystalline graphite

    International Nuclear Information System (INIS)

    Ho, F.H.

    1980-12-01

    Stress concentration factors (SCF) due to geometric discontinuities in graphite specimens are observed to be much less than the theoretical SCF in an elastic material. In fact, the experimental SCF is always less than two and sometimes even less than one. A four parameter Weibull theory which recognizes the grain size effect is found to give an adequate explanation of the above observed discrepancies

  9. 38 CFR 4.129 - Mental disorders due to traumatic stress.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Mental disorders due to... SCHEDULE FOR RATING DISABILITIES Disability Ratings Mental Disorders § 4.129 Mental disorders due to traumatic stress. When a mental disorder that develops in service as a result of a highly stressful event is...

  10. Lithospheric stresses due to radiogenic heating of an ice-silicate planetary body - Implications for Ganymede's tectonic evolution

    Science.gov (United States)

    Zuber, M. T.; Parmentier, E. M.

    1984-01-01

    Thermal evolution models of differentiated and undifferentiated ice-silicate bodies containing long-lived radiogenic heat sources are examined. Lithospheric sresses arise due to volume change of the interior and temperature change in the lithosphere. For an undifferentiated body, the surface stress peaks early in the evolution, while in the differentiated case, stresses peak later and continue to accumulate for longer periods of time. The variation of near-surface stress with depth shows that stresses for the undifferentiated body initially penetrate to great depths, but rapidly concentrate within a few kilometers of the surface. For the differentiated body, elastic stresses never accumulate at a depth greater than a few kilometers. These models are applied to consider long-term rdioactive heating as a possible mechanism of tectonic activity and bright terrain formation on Ganymede.

  11. Stress concentrations in keyways and optimization of keyway design

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2010-01-01

    Keys and keyways are one of the most common shaft–hub connections. Despite this fact very little numerical analysis has been reported. The design is often regulated by standards that are almost half a century old, and most results reported in the literature are based on experimental photoelastic...... analysis. The present paper shows how numerical finite element (FE) analysis can improve the prediction of stress concentration in the keyway. Using shape optimization and the simple super elliptical shape, it is shown that the fatigue life of a keyway can be greatly improved with up to a 50 per cent...... reduction in the maximum stress level. The design changes are simple and therefore practical to realize with only two active design parameters....

  12. Prediction of residual stress distributions due to surface machining and welding and crack growth simulation under residual stress distribution

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Katsuyama, JInya; Onizawa, Kunio; Hashimoto, Tadafumi; Mikami, Yoshiki; Mochizuki, Masahito

    2011-01-01

    Research highlights: → Residual stress distributions due to welding and machining are evaluated by XRD and FEM. → Residual stress due to machining shows higher tensile stress than welding near the surface. → Crack growth analysis is performed using calculated residual stress. → Crack growth result is affected machining rather than welding. → Machining is an important factor for crack growth. - Abstract: In nuclear power plants, stress corrosion cracking (SCC) has been observed near the weld zone of the core shroud and primary loop recirculation (PLR) pipes made of low-carbon austenitic stainless steel Type 316L. The joining process of pipes usually includes surface machining and welding. Both processes induce residual stresses, and residual stresses are thus important factors in the occurrence and propagation of SCC. In this study, the finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining. The thermoelastic-plastic analysis was performed for the welding simulation, and the thermo-mechanical coupled analysis based on the Johnson-Cook material model was performed for the surface machining simulation. In addition, a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stress distributions that are generated by welding and surface machining. The surface machining analysis showed that tensile residual stress due to surface machining only exists approximately 0.2 mm from the machined surface, and the surface residual stress increases with cutting speed. The crack growth analysis showed that the crack depth is affected by both surface machining and welding, and the crack length is more affected by surface machining than by welding.

  13. Optical losses due to tracking error estimation for a low concentrating solar collector

    International Nuclear Information System (INIS)

    Sallaberry, Fabienne; García de Jalón, Alberto; Torres, José-Luis; Pujol-Nadal, Ramón

    2015-01-01

    Highlights: • A solar thermal collector with low concentration and one-axis tracking was tested. • A quasi-dynamic testing procedure for IAM was defined for tracking collector. • The adequation between the concentrator optics and the tracking was checked. • The maximum and long-term optical losses due to tracking error were calculated. - Abstract: The determination of the accuracy of a solar tracker used in domestic hot water solar collectors is not yet standardized. However, while using optical concentration devices, it is important to use a solar tracker with adequate precision with regard to the specific optical concentration factor. Otherwise, the concentrator would sustain high optical losses due to the inadequate focusing of the solar radiation onto its receiver, despite having a good quality. This study is focused on the estimation of long-term optical losses due to the tracking error of a low-temperature collector using low-concentration optics. For this purpose, a testing procedure for the incidence angle modifier on the tracking plane is proposed to determinate the acceptance angle of its concentrator even with different longitudinal incidence angles along the focal line plane. Then, the impact of maximum tracking error angle upon the optical efficiency has been determined. Finally, the calculation of the long-term optical error due to the tracking errors, using the design angular tracking error declared by the manufacturer, is carried out. The maximum tracking error calculated for this collector imply an optical loss of about 8.5%, which is high, but the average long-term optical loss calculated for one year was about 1%, which is reasonable for such collectors used for domestic hot water

  14. Transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations

    International Nuclear Information System (INIS)

    Sugano, Y.

    1980-01-01

    The transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations on two edges are studied by means of the Airy stress function. The purposes of this paper are to present a method of determing the transient thermal stresses in an orthographic rectangular plate with four edges of distinct thermal boundary condition of the third kind which exactly satisfy the traction-free conditions of shear stress over all boundaries including four corners of the plate, and to consider the effects of the anisotropies of material properties and the convective heat transfer on the upper and lower surfaces on the thermal stress distribution. (orig.)

  15. Physiological responses of sweet potato (Ipomoea batatas L. plants due to different copper concentrations

    Directory of Open Access Journals (Sweden)

    Cristina Copstein Cuchiara

    2015-12-01

    Full Text Available At low concentrations, Cu is considered as an essential micronutrient for plants and as a constituent and activator of several enzymes. However, when in excess, Cu can negatively affect plant growth and metabolism. Therefore, the aim of this study was to evaluate physiological responses of sweet potato plants at different Cu concentrations by measuring morphological parameters, antioxidant metabolism, stomatal characteristics, and mineral profile. For this purpose, sweet potato plants were grown hydroponically in complete nutrient solution for six days. Then, the plants were transferred to solutions containing different Cu concentrations, 0.041 (control, 0.082, and 0.164 mM, and maintained for nine days. The main effect of increased Cu concentration was observed in the roots. The sweet potato plants grown in 0.082 mM Cu solution showed increased activity of antioxidant enzymes and no changes in growth parameters. However, at a concentration of 0.164 mM, Cu was transported from the roots to the shoots. This concentration altered morpho-anatomical characteristics and activated the antioxidant system because of the stress generated by excess Cu. On the basis of the results, it can be concluded that the sweet potato plants were able to tolerate Cu toxicity until 0.082 mM.

  16. Airborne concentrations of benzene due to diesel locomotive exhaust in a roundhouse.

    Science.gov (United States)

    Madl, Amy K; Paustenbach, Dennis J

    2002-12-13

    Concentrations of airborne benzene due to diesel exhaust from a locomotive were measured during a worst-case exposure scenario in a roundhouse. To understand the upper bound human health risk due to benzene, an electromotive diesel and a General Electric four-cycle turbo locomotive were allowed to run for four 30-min intervals during an 8-h workshift in a roundhouse. Full-shift and 1-h airborne concentrations of benzene were measured in the breathing zone of surrogate locomotive repairmen over the 8-h workshift on 2 consecutive days. In addition, carbon monoxide was measured continuously; elemental carbon (surrogate for diesel exhaust) was sampled with full-shift area samples; and nitrogen dioxide/nitric oxide was sampled using full-shift and 15-min (nitrogen dioxide only) area samples. Peak concentrations of carbon monoxide ranged from 22.5 to 93 ppm. The average concentration of elemental carbon for each day of the roundhouse study was 0.0543 and 0.0552 microg/m(3 )for an 8-h workshift. These were considered "worst-case" conditions since the work environment was intolerably irritating to the eyes, nose, and throat. Short-term nitrogen dioxide concentrations ranged from 0.81 to 2.63 ppm during the diesel emission events with the doors closed. One-hour airborne benzene concentrations ranged from 0.001 to 0.015 ppm with 45% of the measurements below the detection limit of 0.002-0.004 ppm. Results indicated that the 8-h time-weighted average for benzene in the roundhouse was approximately 100-fold less than the current threshold limit value (TLV) of 0.5 ppm. These data are consistent with other studies, which have indicated that benzene concentrations due to diesel emissions, even in a confined environment, are quite low.

  17. Analysis of Mechanical Stresses Due to Voltage Dips in Fixed-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Veluri, Badrinath; Santos-Martin, David; Jensen, Henrik Myhre

    2011-01-01

    stresses transients that may have a detrimental effect on the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method for the stress history during the voltage dip event, analyses mean and amplitudes of the counted cycles, their occurrence moment and time of duration.......Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque which result in significant high stresses and noticeable vibrations for the wind turbine mechanical system. These events may also have a detrimental effect on the fatigue life of important...

  18. Stresses and strains in pavement structures due to the effect of temperatures

    Directory of Open Access Journals (Sweden)

    Svilar Mila

    2016-01-01

    Full Text Available At its absolute amount, stresses due to the effect of temperature in the pavement structures, especially those rigid, are often of the same order of magnitude as those resulting from vehicles' load, but it happens that due to such impact many slabs become cracked before the road is handed over into operation. The temperature stresses which occur in pavement structures include stresses due to bending and buckling, stresses due to friction and hidden stresses. Stresses caused by the influence of temperature in the pavement structure during the day are generally below the strength of the component materials so they do not cause the consequences for structure. However, appearance of residual stresses and their accumulation after a sufficiently long period of time may lead to failure in structure, i.e. thermal fatigue. The paper presents the effects of temperature changes on the pavement structures in the physical and mechanical terms, and the manner in which the temperature is taken into account during the design of pavement structures.

  19. Method to estimate the internal stresses due to moisture in wood using transmission properties of microwaves

    International Nuclear Information System (INIS)

    Takemura, T.; Taniguchi, T.

    2004-01-01

    The purpose of this paper is to offer a new method for detecting stress in wood due to moisture along the lines of a theory reported previously. According to the theory, the stress in wood could be estimated from the moisture content of the wood and the power voltage of a microwave moisture meter (i.e., attenuation of the projected microwave). This seems to suggest a possibility of utilizing microwaves in the field of stress detection. To develop such an idea, the stress formulas were initially modified to the form of an uni-variable function of power voltage, and the application method of the formulas to detection was tried. Finally, these results were applied to the data of sugi (Cryptomeria japonica) lumber in the previous experiment. The estimated strains showed fairly good agreement with those observed. It could be concluded from this study that the proposed method might be available for detecting stress in wood due to moisture

  20. A Study on Effect of Local Wall Thinning in Carbon Steel Elbow Pipe on Elastic Stress Concentration

    International Nuclear Information System (INIS)

    Kim, Jong Sung; Seo, Jae Seok

    2009-01-01

    Feeder pipes that connect the inlet and outlet headers to the reactor core in CANDU nuclear power plants are considered as safety Class 1 piping items. Therefore, fatigue of feeder pipes should be assessed at design stage in order to verify structural integrity during design lifetime. In accordance with the fatigue assessment result, cumulative usage factors of some feeder pipes have significant values. The feeder pipes made of SA-106 Grade B or C carbon steel have some elbows and bends. An active degradation mechanism for the carbon steel outlet feeder piping is local wall thinning due to flow-accelerated corrosion. Inspection results from plants and metallurgical examinations of removed feeders indicated the presence of localized thinning in the vicinity of the welds in the lower portion of outlet feeders, such as Grayloc hub-to-bend weld, Grayloc hub-to-elbow weld, elbow-to-elbow, and elbow-to-pipe weld. This local wall thinning can cause increase of peak stress due to stress concentration by notch effect. The increase of peak stress results in increase of cumulative usage factor. However, present fatigue assessment doesn't consider the stress concentration due to local wall-thinning. Therefore, it is necessary to assess the effect of local wall thinning on stress concentration. This study investigates the effect of local wall thinning geometry on stress concentration by performing finite element elastic stress analysis

  1. Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

    International Nuclear Information System (INIS)

    Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won

    2016-01-01

    To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m"2. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

  2. Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m{sup 2}. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

  3. Rotation of principal axes and changes of stress due to mine-induced stresses

    Czech Academy of Sciences Publication Activity Database

    Ptáček, Jiří; Koníček, Petr; Staš, Lubomír; Waclawik, Petr; Kukutsch, Radovan

    2015-01-01

    Roč. 52, č. 10 (2015), s. 1440-1447 ISSN 0008-3674. [International Colloquium on Geomechanics and Geophysics /5./. Karolinka, 25.06.2014-27.06.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : mining * principal stress * stress distribution * modified overcoring Subject RIV: DH - Mining , incl. Coal Mining Impact factor: 1.877, year: 2015 http://www.nrcresearchpress.com/doi/full/10.1139/cgj-2014-0364#.VgqDPpc70mt

  4. Geometrically Nonlinear Shell Analysis of Wrinkled Thin-Film Membranes with Stress Concentrations

    Science.gov (United States)

    Tessler, Alexander; Sleight, David W.

    2006-01-01

    Geometrically nonlinear shell finite element analysis has recently been applied to solar-sail membrane problems in order to model the out-of-plane deformations due to structural wrinkling. Whereas certain problems lend themselves to achieving converged nonlinear solutions that compare favorably with experimental observations, solutions to tensioned membranes exhibiting high stress concentrations have been difficult to obtain even with the best nonlinear finite element codes and advanced shell element technology. In this paper, two numerical studies are presented that pave the way to improving the modeling of this class of nonlinear problems. The studies address the issues of mesh refinement and stress-concentration alleviation, and the effects of these modeling strategies on the ability to attain converged nonlinear deformations due to wrinkling. The numerical studies demonstrate that excessive mesh refinement in the regions of stress concentration may be disadvantageous to achieving wrinkled equilibrium states, causing the nonlinear solution to lock in the membrane response mode, while totally discarding the very low-energy bending response that is necessary to cause wrinkling deformation patterns.

  5. Assessment of fructosamine concentrations in cats with acute and chronic stress

    Directory of Open Access Journals (Sweden)

    Lívia Fagundes Moraes

    2011-10-01

    Full Text Available Fructosamine are glycated serum proteins that are formed continuously due to the reaction between glucose and circulating proteins, and corresponding to the blood glucose control assessment over the last one to two weeks in cats. The fructosamine concentration has been used for differentiation between persistent and transient hyperglycemia. Therefore, the determination of fructosamine is considered the gold standard for monitoring glycemia into control in diabetic cats. The objective of this study was to evaluate the influence of acute and chronic stress of cats on serum fructosamine. 62 cats were selected from the Veterinary Hospital of FMVZ - UNESP, Botucatu campus. They were distributed into three groups: cats with a history of any illness or stress condition, excluding Diabetes Mellitus (DM, for a maximum of 48 hours (Group A, n = 21 or for a period exceeding 120 hours (Group B n = 27. The third group (Group C = control was formed by 14 health cats. The groups were evaluated for serum fructosamine, glucose, protein and albumin. In this study, there was a significant increase in the values of fructosamine in animals subjected to acute and chronic stress, but these values remained within the reference range. The animals were, on average, normoglycemic, despite the positive correlation between fructosamine and glucose concentrations. We conclude that the fructosamine concentration is influenced by acute and chronic stress in cats, remaining, however, within the reference range, and therefore, still useful in the diagnosis of DM.

  6. Activity concentration and population dose from 226Ra due to consumption of dietary components

    International Nuclear Information System (INIS)

    Wagh, S.S.; Patra, A.K.; Ravi, P.M.; Sarkar, P.K.

    2012-01-01

    226 Ra (T 1/2 = 1620 years, α-energy 4.78 MeV, 4.59 MeV, γ-energy 186 keV), a product of natural uranium decay series, is abundantly observed in natural environment. Radium, along with its homologue calcium, an essential element in the plant system, is absorbed from the soil by plants and gets redistributed. within different parts of the plants. Because of the long half-life of 226 Ra, it gets accumulated in the human body for along time. The hazard due to ingestion of 226 Ra dissolved in water is reported to be about 40 times higher than that of 90 Sr. This paper deals with the concentration of 226 Ra in different dietary components and ingestion dose from 226 Ra due to consumption of dietary components. Internal radiation exposure to non-human biota due to 226 Ra is also discussed

  7. Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

    International Nuclear Information System (INIS)

    Buznikov, N.A.; Antonov, A.S.; Granovsky, A.B.

    2014-01-01

    The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress

  8. Asymmetric magnetoimpedance in amorphous microwires due to bias current: Effect of torsional stress

    Energy Technology Data Exchange (ETDEWEB)

    Buznikov, N.A., E-mail: n_buznikov@mail.ru [Scientific-Research Institute of Natural Gases and Gas Technologies – GAZPROM VNIIGAZ, Razvilka, Leninsky District, Moscow Region 142717 (Russian Federation); Antonov, A.S. [Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Granovsky, A.B. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

    2014-04-15

    The influence of torsional stress on the asymmetric magnetoimpedance in a glass-coated negative magnetostrictive amorphous microwire due to bias current is studied theoretically. The longitudinal and off-diagonal impedance components are found assuming a simplified spatial distribution of the magnetoelastic anisotropy induced by the torsional stress. The asymmetry in the field dependence of the impedance components is attributed to the combination of the circular magnetic field produced by the bias current and a helical anisotropy induced by the torsional stress. The asymmetry in the magnetoimpedance and the low-field hysteresis are analyzed as a function of the bias current and torsional stress. It is shown that the application of torsional stress significantly changes the value of the bias current required to suppress the hysteresis effect. The results obtained may be useful for applications in magnetic-field and stress sensors. - Highlights: • Effects of torsional stress on magnetoimpedance in amorphous microwire are studied. • Asymmetry in magnetoimpedance is analyzed as a function of bias current and stress. • Torsional stress changes the anisotropy and effects on the microwire impedance. • Field-dependence of impedance is anhysteretic when bias current exceeds threshold value. • Threshold bias current can be tuned by the application of torsional stress.

  9. Average thermal stress in the Al+SiC composite due to its manufacturing process

    International Nuclear Information System (INIS)

    Miranda, Carlos A.J.; Libardi, Rosani M.P.; Marcelino, Sergio; Boari, Zoroastro M.

    2013-01-01

    The numerical analyses framework to obtain the average thermal stress in the Al+SiC Composite due to its manufacturing process is presented along with the obtained results. The mixing of Aluminum and SiC powders is done at elevated temperature and the usage is at room temperature. A thermal stress state arises in the composite due to the different thermal expansion coefficients of the materials. Due to the particles size and randomness in the SiC distribution, some sets of models were analyzed and a statistical procedure used to evaluate the average stress state in the composite. In each model the particles position, form and size are randomly generated considering a volumetric ratio (VR) between 20% and 25%, close to an actual composite. The obtained stress field is represented by a certain number of iso stress curves, each one weighted by the area it represents. Systematically it was investigated the influence of: (a) the material behavior: linear x non-linear; (b) the carbide particles form: circular x quadrilateral; (c) the number of iso stress curves considered in each analysis; and (e) the model size (the number of particles). Each of above analyzed condition produced conclusions to guide the next step. Considering a confidence level of 95%, the average thermal stress value in the studied composite (20% ≤ VR ≤ 25%) is 175 MPa with a standard deviation of 10 MPa. Depending on its usage, this value should be taken into account when evaluating the material strength. (author)

  10. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-01-01

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  11. Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming.

    Science.gov (United States)

    Paital, Biswaranjan; Panda, Sumana Kumari; Hati, Akshaya Kumar; Mohanty, Bobllina; Mohapatra, Manoj Kumar; Kanungo, Shyama; Chainy, Gagan Bihari Nityananda

    2016-02-26

    The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to

  12. Surplus dietary tryptophan reduces plasma cortisol and noradrenaline concentrations and enhances recovery after social stress in pigs.

    Science.gov (United States)

    Koopmans, Sietse Jan; Ruis, Marko; Dekker, Ruud; van Diepen, Hans; Korte, Mechiel; Mroz, Zdzislaw

    2005-07-21

    Social stress occurs in intensive pig farming due to aggressive behavior. This stress may be reduced at elevated dietary levels of tryptophan (TRP). In this study, we compared the effects of high (13.2%) vs. normal (3.4%) dietary TRP to large neutral amino acid (LNAA) ratios on behavior and stress hormones in catheterized pigs ( approximately 50 kg BW), which were exposed to social stress by placing them twice into the territory of a dominant pig ( approximately 60 kg) for 15 min. Pre-stress plasma TRP concentrations were 156+/-15 vs. 53+/-6 micromol/l (psocial confrontations, pigs on the high vs. normal TRP diets show a tendency towards reduced active avoidance behavior (3.2+/-1.1 vs. 6.7+/-1.2 min, psocial confrontations, the post-stress plasma cortisol, noradrenaline and adrenaline concentrations and/or curves (from +5 min to 2 h) were lower/steeper (psurplus TRP in diets for pigs (1) does not significantly affect behavior when exposed to social stress, (2) reduces basal plasma cortisol and noradrenaline concentrations, (3) does not affect the immediate hormonal response to stress, and (4) reduces the long-term hormonal response to stress. In general, pigs receiving high dietary TRP were found to be less affected by stress.

  13. Trends in Pinus ponderosa foliar pigment concentration due to chronic exposure of ozone and acid rain

    International Nuclear Information System (INIS)

    Neuman, L.; Houpis, J.; Anderson, P.

    1991-01-01

    To determine the effects of ozone and acid rain on mature Ponderosa pine trees, Lawrence Livermore National Lab. has collaborated with University of California Berkeley, University of California Davis, California State University Chico, and the US Forest Service at the latter's Chico Tree Improvement Center. Foliar tissue from mature grafted scions of Pinus ponderosa were exposed to two times ambient ozone for ten months and to acid rain (3.0 pH) weekly for 10 weeks using branch exposure chambers. Pigment extracts were analyzed spectrophotometrically for concentrations of chlorophylls a and b, and carotenoid pigments, at 662 nm, 644 nm, and 470 nm, respectively. Pigment concentrations were expressed on a surface area basis. Preliminary results revealed that chlorophyll a showed a downward trend due to the ozone treatment. Acid rain caused no effects on these three pigments, however, chlorophyll b showed an upward trend due to the interaction of ozone and acid rain. The carotenoid pigments showed no changes due to the treatments either singly, or in combination

  14. Multiaxial Stress-Strain Modeling and Effect of Additional Hardening due to Nonproportional Loading

    International Nuclear Information System (INIS)

    Rashed, G.; Ghajar, R.; Farrahi, G.

    2007-01-01

    Most engineering components are subjected to multiaxial rather than uniaxial cyclic loading, which causes multiaxial fatigue. The pre-requisite to predict the fatigue life of such components is to determine the multiaxial stress strain relationship. In this paper the multiaxial cyclic stress-strain model under proportional loading is derived using the modified power law stress-strain relationship. The equivalent strain amplitude consisted of the normal strain excursion and maximum shear strain amplitude is used in the proportional model to include the additional hardening effect due to nonproportional loading. Therefore a new multiaxial cyclic stress-strain relationship is devised for out of phase nonproportional loading. The model is applied to the nonproportional loading case and the results are compared with the other researchers' experimental data published in the literature, which are in a reasonable agreement with the experimental data. The relationship presented here is convenient for the engineering applications

  15. Extreme concentration fluctuations due to local reversibility of mixing in turbulent flows

    Science.gov (United States)

    Xia, Hua; Francois, Nicolas; Punzmann, Horst; Szewc, Kamil; Shats, Michael

    2018-05-01

    Mixing of a passive scalar in a fluid (e.g. a radioactive spill in the ocean) is the irreversible process towards homogeneous distribution of a substance. In a moving fluid, due to the chaotic advection [H. Aref, J. Fluid Mech. 143 (1984) 1; J. M. Ottino, The Kinematics of Mixing: Stretching,Chaos and Transport (Cambridge University Press, Cambridge, 1989)] mixing is much faster than if driven by molecular diffusion only. Turbulence is known as the most efficient mixing flow [B. I. Shraiman and E. D. Siggia, Nature 405 (2000) 639]. We show that in contrast to spatially periodic flows, two-dimensional turbulence exhibits local reversibility in mixing, which leads to the generation of unpredictable strong fluctuations in the scalar concentration. These fluctuations can also be detected from the analysis of the fluid particle trajectories of the underlying flow.

  16. Micro-buckling of periodically layered composites in regions of stress concentration

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Niordson, Christian Frithiof

    2016-01-01

    -buckling related failure in regions of stress concentrations. A series of parametric studies show the effect of non-uniform stress distributions due to bending loads and the presence of geometrical features such as notches and holes on the initiation of micro-buckling. The contribution of the bending stiffness...... of the reinforcing layers on the resistance against micro-buckling introduces a dependence on the layer thickness, resulting in size-scale dependent strength limits. Therefore, both the shape and dimensions of the considered geometrical features and the layering thickness of the micro-structure are varied as part...... of the parametric studies. Moreover, the impact of imperfections in the composite micro-structure on the strength of the considered specimens is investigated....

  17. Nonlinear Heart Rate Variability features for real-life stress detection. Case study: students under stress due to university examination.

    Science.gov (United States)

    Melillo, Paolo; Bracale, Marcello; Pecchia, Leandro

    2011-11-07

    This study investigates the variations of Heart Rate Variability (HRV) due to a real-life stressor and proposes a classifier based on nonlinear features of HRV for automatic stress detection. 42 students volunteered to participate to the study about HRV and stress. For each student, two recordings were performed: one during an on-going university examination, assumed as a real-life stressor, and one after holidays. Nonlinear analysis of HRV was performed by using Poincaré Plot, Approximate Entropy, Correlation dimension, Detrended Fluctuation Analysis, Recurrence Plot. For statistical comparison, we adopted the Wilcoxon Signed Rank test and for development of a classifier we adopted the Linear Discriminant Analysis (LDA). Almost all HRV features measuring heart rate complexity were significantly decreased in the stress session. LDA generated a simple classifier based on the two Poincaré Plot parameters and Approximate Entropy, which enables stress detection with a total classification accuracy, a sensitivity and a specificity rate of 90%, 86%, and 95% respectively. The results of the current study suggest that nonlinear HRV analysis using short term ECG recording could be effective in automatically detecting real-life stress condition, such as a university examination.

  18. Stress analysis on passenger deck due to modification from passenger ship to vehicle-carrying ship

    Science.gov (United States)

    Zubaydi, A.; Sujiatanti, S. H.; Hariyanto, T. R.

    2018-03-01

    Stress is a basic concept in learning about material mechanism. The main focus that needs to be brought to attention in analyzing stress is strength, which is the structural capacity to carry or distribute loads. The structural capacity not only measured by comparing the maximum stress with the material’s yield strength but also with the permissible stress required by the Indonesian Classification Bureau (BKI), which certainly makes it much safer. This final project analyzes stress in passenger deck that experiences modification due to load changes, from passenger load to vehicle one, carrying: 6-wheels truck with maximum weight of 14 tons, a passenger car with maximum weight of 3.5 tons, and a motorcycle with maximum weight of 0.4 tons. The deck structure is modelled using finite element software. The boundary conditions given to the structural model are fix and simple constraint. The load that works on this deck is the deck load which comes from the vehicles on deck with three vehicles’ arrangement plans. After that, software modelling is conducted for analysis purpose. Analysis result shows a variation of maximum stress that occurs i.e. 135 N/mm2, 133 N/mm2, and 152 N/mm2. Those maximum stresses will not affect the structure of passenger deck’s because the maximum stress that occurs indicates smaller value compared to the Indonesian Classification Bureau’s permissible stress (175 N/mm2) as well as the material’s yield strength (235 N/mm2). Thus, the structural strength of passenger deck is shown to be capable of carrying the weight of vehicles in accordance with the three vehicles’ arrangement plans.

  19. A modeling study of effective radiative forcing and climate response due to increased methane concentration

    Directory of Open Access Journals (Sweden)

    Bing Xie

    2016-12-01

    Full Text Available An atmospheric general circulation model BCC_AGCM2.0 and observation data from ARIS were used to calculate the effective radiative forcing (ERF due to increased methane concentration since pre-industrial times and its impacts on climate. The ERF of methane from 1750 to 2011 was 0.46 W m−2 by taking it as a well-mixed greenhouse gas, and the inhomogeneity of methane increased its ERF by about 0.02 W m−2. The change of methane concentration since pre-industrial led to an increase of 0.31 °C in global mean surface air temperature and 0.02 mm d−1 in global mean precipitation. The warming was prominent over the middle and high latitudes of the Northern Hemisphere (with a maximum increase exceeding 1.4 °C. The precipitation notably increased (maximum increase of 1.8 mm d−1 over the ocean between 10°N and 20°N and significantly decreased (maximum decrease >–0.6 mm d−1 between 10°S and 10°N. These changes caused a northward movement of precipitation cell in the Intertropical Convergence Zone (ITCZ. Cloud cover significantly increased (by approximately 4% in the high latitudes in both hemispheres, and sharply decreased (by approximately 3% in tropical areas.

  20. Estimates concentrations in bottled 222Rn of the dose due to mineral waters in Iran

    International Nuclear Information System (INIS)

    Assadi, M. R.; Esmaealnejad, M.; Rahmatinejad, Z.

    2006-01-01

    Radon is a radionuclide that has the main role in exposure. Radon in water causes exposure in whole body but the largest dose being received by the stomach, as EPA (Environmental Protection Agency) estimates that radon in drinking water causes about 168 cancer deaths per year: 89 p ercent f rom lung cancer caused by breathing released to the indoor air from water and 11 p ercent f rom stomach cancer caused by consuming water containing radon. Now days the consumption of bottled mineral waters has become very popular. As is known, some kinds of mineral waters contain naturally occurring radionuclides in higher concentration than the usual drinking (tap) water. Surveys and reports on radon in most surface waters is low compared with radon level in groundwater and mineral water. In our work, the concentration of Rn(222) was determined in some bottled mineral waters available in Iran , and in next step the dose contribution ; due to ingestion ; for 1 l d -1 bottled mineral water consumption.

  1. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-01-01

    High energy synchrotron XRD was employed to determine the lattice strain ε{111}and diffraction peak intensity ratio R{200}in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the ε{111}–cos 2 ψ plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90° ferroelectric domains, quantified in terms of R{200}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks

  2. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    Science.gov (United States)

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-07-01

    High energy synchrotron XRD was employed to determine the lattice strain ɛ{111} and diffraction peak intensity ratio R{200} in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the ɛ{111}-cos2 ψ plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90° ferroelectric domains, quantified in terms of R{200}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks.

  3. Differences in response to heat stress due to production level and breed of dairy cows

    Science.gov (United States)

    Gantner, Vesna; Bobic, Tina; Gantner, Ranko; Gregic, Maja; Kuterovac, Kresimir; Novakovic, Jurica; Potocnik, Klemen

    2017-09-01

    The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

  4. The concentration of fear: mice's behavioural and physiological stress responses to different degrees of predation risk

    Science.gov (United States)

    Sánchez-González, Beatriz; Planillo, Aimara; Navarro-Castilla, Álvaro; Barja, Isabel

    2018-02-01

    Predation is an unavoidable and dangerous fact in the lifetime of prey animals and some sign of the proximity of a predator may be enough to trigger a response in the prey. We investigated whether different degrees of predation risk by red foxes ( Vulpes vulpes) evoke behavioural and physiological stress responses in wood mice ( Apodemus sylvaticus) . We examined the variation in mice responses due to individual factors (sex and reproductive status) and related them to the concentration of the volatile compounds from fox faeces over time. In our experiment, we introduced predation cues into four plots, each subjected to a different concentration treatment (0, 10, 50 and 100% concentration of fresh faeces of red fox), based on the following outline: initial odourless phase 0, phase1 in which predation treatment was renewed daily, and phase 2 in which we renewed the treatment only on the first day. Wood mice were live trapped during all three phases and the physiological response was measured non-invasively by analysing faecal corticosterone metabolites (FCM) in freshly collected faeces. Data were analysed by Generalized Linear Mixed Models. Overall, males were trapped less often than females, and reproductively active individuals from both sexes avoided traps more than non-reproductively active individuals, especially in medium- and high- concentration plots. Variations in FCM concentrations were explained by plot, the interaction between plot and treatment phase, and the interaction between the treatment phase and the reproductive status. During phase 1, we detected a significant rise in FCM levels that increased with predator faecal odour concentration. Additionally, reproductively active individuals showed a strong physiological response during both phases 1 and 2 in all plots, except the control plot. Our results indicated that wood mice are able to discriminate different degrees of predation risk, which allows them to trigger gradual changes in their

  5. Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix

    Energy Technology Data Exchange (ETDEWEB)

    Tummala, Hareesh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Capolungo, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-19

    This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution of mechanical fields due to dislocations was found to have a non-negligible effect on such process.

  6. Polonium-210 concentration of cigarettes traded in Cuba and their estimated dose contribution due to smoking

    International Nuclear Information System (INIS)

    Brigido Flores, O.; Montalvan Estrada, A.; Fabelo Bonet, O.; Barreras Caballero, A.

    2015-01-01

    Cigarette smoking is one of the pathways that might contribute significantly to the increase in the radiation dose reaching man, due to the relatively large concentrations of polonium-210 found in tobacco leaves. The results of 200 Po determination on the 11 most frequently smoked brands of cigarettes and cigars which constitute over 75% of the total cigarette consumption in Cuba are presented and discussed. Moreover, the polonium content in cigarette smoke was estimated on the basis of its activity in cigarettes, ash, fresh filters and post-smoking filters. 210 Po was determined by gas flow proportional detector after spontaneous deposition of 210 Po on a high copper-content disk. The annual committed equivalent dose for lungs and the annual effective dose for smokers between 12-17 years old and for adults were calculated on the basis of the 210 Po inhalation through cigarette smoke. The results showed concentration ranging from 9.3 to 14.4 mBq per cigarette with a mean value of 11.8 ± 0.6 mBq.Cig -1 . the results of this work indicate that Cuban smokers who smoke one pack (20 cigarettes) per day inhale from 62 to 98 mBq.d -1 of 210 Po and smokers between 12-17 years old who consume 10 cigarettes daily inhale from 30-50 mBq.d -1 . The average committed equivalent dose for lungs is estimated to be 466 ± 36 and 780 ± 60 μSv.year -1 for young and adult smokers, respectively and annual committed effective dose is calculated to be 60 ± 5 and 100 ± 8 μSv for these two groups of smokers, respectively. (Author)

  7. Stress triggering of earthquakes and subsidence in the Louisiana coastal zone due to hydrocarbon production

    Science.gov (United States)

    Mallman, Ellen P.

    This thesis presents contributions towards better understanding of the interaction between earthquakes through elastic stress triggering and the role of hydrocarbon production on subsidence and land loss in southern Louisiana. The first issue addressed in this thesis is that of the role of static stress changes on earthquake triggering. The first study investigated whether observed changes in seismicity rate following the 1992 Landers, California and 1995 Kobe, Japan earthquakes are accurately predicted by elastic Coulomb stress transfer models. The analyses found that for all the tested DeltaCFS models wherever seismicity rate changes could be resolved the rate increased regardless of whether the DeltaCFS theoretically promoted or inhibited failure. The second study the common definition of a stress shadow was extended to independently test the stress shadow hypothesis using a global catalog of seismicity. The analyses indicated that while stress shadows are subtle, they are present in the global catalog. It also explains why "classical" stress shadows, similar to what was observed following the 1906 San Francisco earthquake are rarely observed for individual main shocks. The second issue addressed in this thesis is the role of hydrocarbon production on subsidence and land loss in the Louisiana Coastal Zone. The two studies in this thesis extend previous work by modeling the effect of oil and gas production in the region in two ways. First, multiple producing oil and gas fields and multiple epochs of leveling data are considered to provide constraints on predicted subsidence. Second, the role of compaction of the reservoir bounding shales on the regional subsidence signal is included. The results of the two studies on the role of hydrocarbon production on subsidence in the Louisiana Coastal Zone indicate that regional models of subsidence must include the effects of production-induced subsidence due to both sands and shales, but that this can not account for the

  8. Analysis of stress concentration in the Dutton groove regions of the Super Lightweight External Tank

    Science.gov (United States)

    Ahmed, R.

    1995-05-01

    Because the 2195 aluminum-lithium material of the super lightweight external tank (SLWT ET) has a lower toughness than the 2219 aluminum used in previous ET's, careful attention must be paid to stress concentrations. This report details the analysis performed on some of the stress concentrations in the orthogrid panels of the liquid hydrogen tank.

  9. Evaluation of Activity Concentration Values and Doses due to the Transport of Low Level Radioactive Material

    Energy Technology Data Exchange (ETDEWEB)

    Rawl, Richard R [ORNL; Scofield, Patricia A [ORNL; Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL

    2010-04-01

    The International Atomic Energy Agency (IAEA) initiated an international Coordinated Research Project (CRP) to evaluate the safety of transport of naturally occurring radioactive material (NORM). This report presents the United States contribution to that IAEA research program. The focus of this report is on the analysis of the potential doses resulting from the transport of low level radioactive material. Specific areas of research included: (1) an examination of the technical approach used in the derivation of exempt activity concentration values and a comparison of the doses associated with the transport of materials included or not included in the provisions of Paragraph 107(e) of the IAEA Safety Standards, Regulations for the Safe Transport of Radioactive Material, Safety Requirements No. TS-R-1; (2) determination of the doses resulting from different treatment of progeny for exempt values versus the A{sub 1}/A{sub 2} values; and (3) evaluation of the dose justifications for the provisions applicable to exempt materials and low specific activity materials (LSA-I). It was found that the 'previous or intended use' (PIU) provision in Paragraph 107(e) is not risk informed since doses to the most highly exposed persons (e.g., truck drivers) are comparable regardless of intended use of the transported material. The PIU clause can also have important economic implications for co-mined ores and products that are not intended for the fuel cycle but that have uranium extracted as part of their industrial processing. In examination of the footnotes in Table 2 of TS-R-1, which identifies the progeny included in the exempt or A1/A2 values, there is no explanation of how the progeny were selected. It is recommended that the progeny for both the exemption and A{sub 1}/A{sub 2} values should be similar regardless of application, and that the same physical information should be used in deriving the limits. Based on the evaluation of doses due to the transport of low

  10. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    Science.gov (United States)

    Bandriyana, B.; Utaja

    2010-06-01

    Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  11. Axial contraction in etched optical fiber due to internal stress reduction.

    Science.gov (United States)

    Lim, Kok-Sing; Yang, Hang-Zhou; Chong, Wu-Yi; Cheong, Yew-Ken; Lim, Chin-Hong; Ali, Norfizah M; Ahmad, Harith

    2013-02-11

    When an optical fiber is dipped in an etching solution, the internal stress profile in the fiber varies with the fiber diameter. We observed a physical contraction as much as 0.2% in the fiber axial dimension when the fiber was reduced from its original diameter to ~6 µm through analysis using high resolution microscope images of the grating period of an etched FBG at different fiber diameters. This axial contraction is related to the varying axial stress profile in the fiber when the fiber diameter is reduced. On top of that, the refractive index of fiber core increases with reducing fiber diameter due to stress-optic effect. The calculated index increment is as much as 1.8 × 10(-3) at the center of fiber core after the diameter is reduced down to ~6 µm. In comparison with the conventional model that assumes constant grating period and neglects the variation in stress-induced index change in fiber core, our proposed model indicates a discrepancy as much as 3nm in Bragg wavelength at a fiber diameter of ~6 µm.

  12. Evaluation of local stress and local hydrogen concentration at grain boundary using three-dimensional polycrystalline model

    International Nuclear Information System (INIS)

    Ebihara, Ken-ichi; Itakura, Mitsuhiro; Yamaguchi, Masatake; Kaburaki, Hideo; Suzudo, Tomoaki

    2010-01-01

    The decohesion model in which hydrogen segregating at grain boundaries reduces cohesive energy is considered to explain hydrogen embrittlement. Although there are several experimental and theoretical supports of this model, its total process is still unclear. In order to understand hydrogen embrittlement in terms of the decohesion model, therefore, it is necessary to evaluate stress and hydrogen concentration at grain boundaries under experimental conditions and to verify the grain boundary decohesion process. Under this consideration, we evaluated the stress and the hydrogen concentration at grain boundaries in the three-dimensional polycrystalline model which was generated by the random Voronoi tessellation. The crystallographic anisotropy was given to each grain. As the boundary conditions of the calculations, data extracted from the results calculated in the notched round-bar specimen model under the tensile test condition in which fracture of the steel specimen is observed was given to the polycrystalline model. As a result, it was found that the evaluated stress does not reach the fracture stress which was estimated under the condition of the evaluated hydrogen concentration by first principles calculations. Therefore, it was considered that the initiation of grain boundary fracture needs other factors except the stress concentration due to the crystallographic anisotropy. (author)

  13. Minimization of stress concentration factor in cylindrical pressure vessels with ellipsoidal heads

    International Nuclear Information System (INIS)

    Magnucki, K.; Szyc, W.; Lewinski, J.

    2002-01-01

    The paper presents the problem of stress concentration in a cylindrical pressure vessel with ellipsoidal heads subject to internal pressure. At the line, where the ellipsoidal head is adjacent to the circular cylindrical shell, a shear force and bending moment occur, disturbing the membrane stress state in the vessel. The degree of stress concentration depends on the ratio of thicknesses of both the adjacent parts of the shells and on the relative convexity of the ellipsoidal head, with the range for radius-to-thickness ratio between 75 and 125. The stress concentration was analytically described and, afterwards, the effect of these values on the stress concentration ratio was numerically examined. Results of the analysis are shown on charts

  14. Heavy Metal Stress, Signaling, and Tolerance Due to Plant-Associated Microbes: An Overview

    Science.gov (United States)

    Tiwari, Shalini; Lata, Charu

    2018-01-01

    Several anthropogenic activities including mining, modern agricultural practices, and industrialization have long-term detrimental effect on our environment. All these factors lead to increase in heavy metal concentration in soil, water, and air. Soil contamination with heavy metals cause several environmental problems and imparts toxic effect on plant as well as animals. In response to these adverse conditions, plants evolve complex molecular and physiological mechanisms for better adaptability, tolerance, and survival. Nowadays conventional breeding and transgenic technology are being used for development of metal stress resistant varieties which, however, are time consuming and labor intensive. Interestingly the use of microbes as an alternate technology for improving metal tolerance of plants is gaining momentum recently. The use of these beneficial microorganisms is considered as one of the most promising methods for safe crop-management practices. Interaction of plants with soil microorganisms can play a vital role in acclimatizing plants to metalliferous environments, and can thus be explored to improve microbe-assisted metal tolerance. Plant-associated microbes decrease metal accumulation in plant tissues and also help to reduce metal bioavailability in soil through various mechanisms. Nowadays, a novel phytobacterial strategy, i.e., genetically transformed bacteria has been used to increase remediation of heavy metals and stress tolerance in plants. This review takes into account our current state of knowledge of the harmful effects of heavy metal stress, the signaling responses to metal stress, and the role of plant-associated microbes in metal stress tolerance. The review also highlights the challenges and opportunities in this continued area of research on plant–microbe–metal interaction. PMID:29681916

  15. Heavy Metal Stress, Signaling, and Tolerance Due to Plant-Associated Microbes: An Overview

    Directory of Open Access Journals (Sweden)

    Shalini Tiwari

    2018-04-01

    Full Text Available Several anthropogenic activities including mining, modern agricultural practices, and industrialization have long-term detrimental effect on our environment. All these factors lead to increase in heavy metal concentration in soil, water, and air. Soil contamination with heavy metals cause several environmental problems and imparts toxic effect on plant as well as animals. In response to these adverse conditions, plants evolve complex molecular and physiological mechanisms for better adaptability, tolerance, and survival. Nowadays conventional breeding and transgenic technology are being used for development of metal stress resistant varieties which, however, are time consuming and labor intensive. Interestingly the use of microbes as an alternate technology for improving metal tolerance of plants is gaining momentum recently. The use of these beneficial microorganisms is considered as one of the most promising methods for safe crop-management practices. Interaction of plants with soil microorganisms can play a vital role in acclimatizing plants to metalliferous environments, and can thus be explored to improve microbe-assisted metal tolerance. Plant-associated microbes decrease metal accumulation in plant tissues and also help to reduce metal bioavailability in soil through various mechanisms. Nowadays, a novel phytobacterial strategy, i.e., genetically transformed bacteria has been used to increase remediation of heavy metals and stress tolerance in plants. This review takes into account our current state of knowledge of the harmful effects of heavy metal stress, the signaling responses to metal stress, and the role of plant-associated microbes in metal stress tolerance. The review also highlights the challenges and opportunities in this continued area of research on plant–microbe–metal interaction.

  16. Initial stresses in two-layer metal domes due to imperfections of their production and assemblage

    Directory of Open Access Journals (Sweden)

    Lebed Evgeniy Vasil’evich

    2015-04-01

    Full Text Available The process of construction of two-layer metal domes is analyzed to illustrate the causes of initial stresses in the bars of their frames. It has been noticed that it is impossible to build such structures with ideal geometric parameters because of imperfections caused by objective reasons. These imperfections cause difficulties in the process of connection of the elements in the joints. The paper demonstrates the necessity of fitting operations during assemblage that involve force fitting and yield initial stresses due to imperfections. The authors propose a special method of computer modeling of enforced elimination of possible imperfections caused by assemblage process and further confirm the method by an analysis of a concrete metal dome.

  17. Assessment of stress due to hot ambience in donkeys from arid tracts in India

    Directory of Open Access Journals (Sweden)

    Kataria N.

    2010-11-01

    Full Text Available To assess the stress due to hot ambience in donkeys from arid tracts in Rajasthan state, India, serum prolactin and cortisol levels were determined by radioimmunoassay. The blood samples to harvest the serum were collected from the same animals during moderate (maximum temperature of 28 C - 29 C and hot (maximum temperature of 45 C- 46 C ambiences. During hot ambience the animals showed significantly (p0.05 higher levels of serum prolactin and cortisol when compared to the moderate ambience. The mean rise in prolactin was 4.42 times whereas cortisol levels were 4.22 times higher. Further a multiple fold rise in serum prolactin clearly suggested that it can also be used as an indicator of stress in donkeys along with the cortisol.

  18. Numerical simulation of the double pits stress concentration in a curved casing inner surface

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2016-12-01

    Full Text Available Sour or sweet oil fields development is common in recent years. Casing and tubing are usually subjected to pitting corrosion because of exposure to the strong corrosion species, such as CO2, H2S, and saline water. When the corrosion pits formed in the casing inner surface, localized stress concentration will occur and the casing strength will be degraded. Thus, it is essential to evaluate the degree of stress concentration factor accurately. This article performed a numerical simulation on double pits stress concentration factor in a curved inner surface using the finite element software ABAQUS. The results show that the stress concentration factor of double pits mainly depends on the ratio of two pits distance to the pit radius (L/R. It should not be only assessed by the absolute distance between the two pits. When the two pits are close and tangent, the maximum stress concentration factor will appear on the inner tangential edges. Stress concentration increased by double pits in a curved casing inner surface is more serious than that in a flat surface. A correction factor of 1.9 was recommended in the curved inner surface double pits stress concentration factor predict model.

  19. Stress Concentration and Its Mitigation Techniques in Flat Plate with Singularities - A Critical Review

    Directory of Open Access Journals (Sweden)

    Shubhashish Sanyal

    2012-01-01

    Full Text Available A number of analytical, numerical & experimental techniques are available for the reduction of stress concentration factor around discontinuities. Using various techniques the SCF around different discontinuities in a rectangular plate made up of different materials under different loading conditions have been reported in literature. Mitigation of stress concentration around different types of discontinuity is also reported in literature. This paper is to present an analysis and overview of emerging techniques developed for analysis as well as mitigation of stress concentration. The proposed methods in literature are compared.

  20. Lithosphere stress changes due to groundwater unloading in North China Plain

    Science.gov (United States)

    Pang, Yajin; Zhang, Huai; Shi, Yaolin

    2015-04-01

    During the past 50 years, excessive groundwater pumping has led to the continuous decline of groundwater table in North China Plain, which becomes one of the global hotspots of groundwater depletion. Over most of the rural areas of the plain, the shallow aquifer has experienced a water-table decline of more than 15m, with greater declines up to 50m in most urban centres, such as Beijing, Tangshan, Shijiangzhuang and so forth in 1960-2000. The entire groundwater depletion area covers a total area of approximately 56,273 km2 , more than 40% of the North China Plain. The vast area of enormous groundwater exploitation in North China Plain will definitely unload the lithosphere and create stress perturbations, the problem is if the stresses change large enough to affect tectonic activities. In this essay, we set up a 3 dimensional numerical visco-elastic model to discuss the effect of groundwater over-pumping on the lithosphere deformation and stress state in North China Plain. Based on the records of total groundwater-table decline during 1960-2010 in North China Plain, we estimate the accumulated deformation and lithosphere stress due to unloading of human-induced groundwater depletion. The area in the model ranges from 34° To 42°N, and 112° To 119°E, including the major groundwater depression cones in North China Plain. According to the simulating result, the maximum surface vertical uplift caused by groundwater unloading is 8cm. Meanwhile cumulative horizontal crustal stress changes near the surface goes up to 100kPa, and up to 40kPa at 15km depth where most earthquakes occurred in this area. The tectonic compressive stress rate is about 0.25kPa per year. Therefore, the stress changes due to groundwater pumping is significant compared with the tectonic driven stress changes. As China developed rapidly since 1978, the groundwater table mainly declined after 1978. Taking the earthquake catalog in the vicinity of groundwater depression zone into consideration, we

  1. Cortisol and ghrelin concentrations following a cold pressor stress test in overweight individuals with and without night eating.

    Science.gov (United States)

    Geliebter, A; Carnell, S; Gluck, M E

    2013-08-01

    To explore appetite-related hormones following stress in overweight individuals, and their relationship with night eating (NE) status. We measured plasma cortisol and ghrelin concentrations, and recorded ratings of stress and hunger in response to a physiological laboratory stressor (cold pressor test, CPT), in overweight women with (n=11; NE) and without (n=17; non-NE) NE. Following the CPT, cortisol (Plevels increased, as did stress and hunger ratings (all Pcortisol (Plevels than non-NE. NE also had greater cortisol area under the curve (AUC) than non-NE (P=0.019), but not when controlling for baseline cortisol levels. Ghrelin baseline and AUC did not differ between groups. NE showed higher AUC stress (Pcortisol, ghrelin, stress and hunger following a laboratory stressor, and there was some evidence for greater increases in cortisol and subjective stress among NE. The greater AUC cortisol level in NE was due to higher baseline levels, but the group difference in stress was in direct response to the stressor. Our results support a role for cortisol and stress in NE.

  2. Polyol concentrations in Aspergillus repens grown under salt stress.

    Science.gov (United States)

    Kelavkar, U P; Chhatpar, H S

    1993-09-01

    Na(+), K(+) and the ratio of Na(+)/K(+) were higher in cells of the halotolerant Aspergillus repens grown with 2 M NaCl than without NaCl. The osmolytes, proline, glycerol, betaine and glutamate, did not affect the Na(+)/K(+) ratio, nor the polyol content of cells under any conditions. The concentrations of polyols, consisting of glycerol, arabitol, erythritol and mannitol, changed markedly during growth, indicating that they have a crucial role in osmotic adaptation.

  3. Emotion regulation's relationships with depression, anxiety and stress due to imagined smartphone and social media loss.

    Science.gov (United States)

    Elhai, Jon D; Hall, Brian J; Erwin, Meredith Claycomb

    2018-03-01

    A sample of 359 students participated in a web survey, administered the Emotion Regulation Questionnaire, and Depression Anxiety Stress Scale-21 (DASS-21) as a pre-test. We subsequently randomly assigned subjects to either 1) a smart phone loss group or 2) social media accounts loss group. We asked them to imagine losing two days' access to the technology in their respective group, and rate associated symptoms using the DASS-21. Compared to subjects in the smartphone loss group, social media loss subjects evidenced stronger relations between suppressive emotion regulation with depression, anxiety and stress from imagined loss. Controlling for age and gender, social media loss subjects' increased use of suppression, and decreased use of cognitive reappraisal in emotion regulation, were related to depression, stress and (for suppression only) anxiety due to imagined lost social media. Emotion regulation was not related to psychopathology for subjects in the smartphone loss scenario. Results suggest that emotion dysregulation may be associated with psychopathology from social media loss. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Prenatal Stress due to a Natural Disaster Predicts Adiposity in Childhood: The Iowa Flood Study

    Directory of Open Access Journals (Sweden)

    Kelsey N. Dancause

    2015-01-01

    Full Text Available Prenatal stress can affect lifelong physical growth, including increased obesity risk. However, human studies remain limited. Natural disasters provide models of independent stressors unrelated to confounding maternal characteristics. We assessed degree of objective hardship and subjective distress in women pregnant during severe flooding. At ages 2.5 and 4 years we assessed body mass index (BMI, subscapular plus triceps skinfolds (SS + TR, an index of total adiposity, and SS : TR ratio (an index of central adiposity in their children (n=106. Hierarchical regressions controlled first for several potential confounds. Controlling for these, flood exposure during early gestation predicted greater BMI increase from age 2.5 to 4, as well as total adiposity at 2.5. Greater maternal hardship and distress due to the floods, as well as other nonflood life events during pregnancy, independently predicted greater increase in total adiposity between 2.5 and 4 years. These results support the hypothesis that prenatal stress increases adiposity beginning in childhood and suggest that early gestation is a sensitive period. Results further highlight the additive effects of maternal objective and subjective stress, life events, and depression, emphasizing the importance of continued studies on multiple, detailed measures of maternal mental health and experience in pregnancy and child growth.

  5. Quantifying Cyclic Thermal Stresses Due to Solar Exposure in Rock Fragments in Gale Crater, Mars

    Science.gov (United States)

    Hallet, B.; Mackenzie-Helnwein, P.; Sletten, R. S.

    2017-12-01

    Curiosity and earlier rovers on Mars have revealed in detail rocky landscapes with decaying outcrops, rubble, stone-littered regolith, and bedrock exposures that reflect the weathering processes operating on rock exposed to Mars' cold and hyperarid environment. Evidence from diverse sources points to the importance of thermal stresses driven by cyclic solar exposure in contributing to the mechanical weathering of exposed rock and generation of regolith in various settings on Earth [1,2,3], and even more so on extraterrestrial bodies where large, rapid cyclic temperature variations are frequent (e.g. Mars [4], as well as comets [5], asteroids [6] and other airless bodies [7]). To study these thermal stresses, we use a 3d finite element (FE) model constrained by ground-based surface temperature measurements from Curiosity's Environmental Monitoring Station (REMS). The numerical model couples radiation and conduction with elastic response to determine the temperature and stress fields in individual rocks on the surface of Mars based on rock size and thermo-mechanical properties. We provide specific quantitative results for boulder-size basalt rocks resting on the ground using a realistic thermal forcing that closely matches the REMS temperature observations, and related thermal inertia data. Moreover, we introduce analytical studies showing that these numerical results can readily be generalized. They are quite universal, informing us about thermal stresses due to cyclic solar exposure in general, for rock fragments of different sizes, lithologies, and fracture- thermal- and mechanical-properties. Using Earth-analogue studies to gain insight, we also consider how the shapes, fractures, and surface details of rock fragments imaged by Curiosity likely reflect the importance of rock breakdown due to thermal stresses relative to wind-driven rock erosion and other surface processes on Mars. References:[1] McFadden L et al. (2005) Geol. Soc.Am. Bull. 117(1-2): 161-173 [2

  6. Stress concentration factor and stress intensity factor on hard metals in connection with the wear characteristics

    International Nuclear Information System (INIS)

    Dawihl, W.; Altmeyer, G.

    1977-01-01

    Description of a method to determine stress intensity factors on hard metals by lapping in notches of different diameter. Dependence of the values of the stress intensity factors on the size of the notch base diameter. For tungsten carbide hard metals with 6% Co, determination of a final value of 250 Nmm -3 / 2 . Characterisation of the stress intensity factor governed by the surface roughness which is decisive for the assessment of the wear-resistant behaviour. (orig.) [de

  7. Stress concentrations in an impregnated fibre bundle with random fibre packing

    OpenAIRE

    Swolfs, Y.; Gorbatikh, L.; Romanov, V.; Orlova, S.; Lomov, S. V.; Verpoest, I.

    2013-01-01

    The stress redistribution after a single fibre break is a fundamental issue in longitudinal strength models for unidirectional composites. Current models assume hexagonal or square fibre packings. In the present work, random fibre packings were modelled using 3D finite element analysis and compared to ordered fibre packings. Significant differences in the stress redistribution are found. Compared to square and hexagonal packings, random fibre packings result in smaller stress concentration fa...

  8. Activity concentration and AACED due to 40K in some selected medicinal plants

    International Nuclear Information System (INIS)

    Chandrashekara, K.; Radhakrishna, A.P.; Somashekarappa, H.M.

    2017-01-01

    The activity concentrations in soil and medicinal plants, soil to plant transfer factors (TF), and Average Annual Committed Effective Dose (AACED) of 40 K in prominent medicinal plants of Malnad Kerala were estimated. The range of activity concentrations were 144.15 - 558.99 and 405.87 - 2990.75 Bq kg -1 in soil and medicinal plants respectively. The TF was found to vary from 2.34 to 14.84, whereas AACED varied in the range 2.51 - 18.54 mSv y -1 . The study may help to form the database and safety regulations connected with 40 K activity in medicinal plants. (author)

  9. Study on fatigue strength of specimens with stress concentrators accounting for inelastic cyclic strains

    International Nuclear Information System (INIS)

    Troshchenko, V.T.; Khamaza, L.A.; Mishchenko, Yu.D.

    1978-01-01

    A possibility of plotting the fatigue curves for structural elements with stress concentrators was examined according to the results of testing smooth specimens made of 1Kh2M steel. The technique has been suggested, based on using the Neuber formula, while taking into account the dependence of the effective coefficient of stresses concentration on the number of cycles prior to failure. A good agreement between the calculated and the experimental data has been obtained

  10. High concentrations of cadmium, cerium and lanthanum in indoor air due to environmental tobacco smoke

    International Nuclear Information System (INIS)

    Böhlandt, Antje; Schierl, Rudolf; Diemer, Juergen; Koch, Christoph; Bolte, Gabriele; Kiranoglu, Mandy; Fromme, Hermann; Nowak, Dennis

    2012-01-01

    Background: Environmental tobacco smoke (ETS) is one of the most important sources for indoor air pollution and a substantial threat to human health, but data on the concentrations of the trace metals cerium (Ce) and lanthanum (La) in context with ETS exposure are scarce. Therefore the aim of our study was to quantify Ce and La concentrations in indoor air with high ETS load. Methods: In two subsequent investigations Ce, La and cadmium (Cd) in 3 smokers' (11 samples) and 7 non-smokers' (28 samples) households as well as in 28 hospitality venues in Southern Germany were analysed. Active sampling of indoor air was conducted continuously for seven days in every season in the smokers' and non-smokers' residences, and for 4 h during the main visiting hours in the hospitality venues (restaurants, pubs, and discotheques). Results: In terms of residences median levels of Cd were 0.1 ng/m 3 for non-smokers' and 0.8 ng/m 3 for smokers' households. Median concentrations of Ce were 0.4 ng/m 3 and 9.6 ng/m 3 , and median concentrations of La were 0.2 ng/m 3 and 5.9 ng/m 3 for non-smokers' and for smokers' households, respectively. In the different types of hospitality venues median levels ranged from 2.6 to 9.7 ng/m 3 for Cd, from 18.5 to 50.0 ng/m 3 for Ce and from 10.6 to 23.0 ng/m 3 for La with highest median levels in discotheques. Conclusions: The high concentrations of Ce and La found in ETS enriched indoor air of smokers' households and hospitality venues are an important finding as Ce and La are associated with adverse health effects and data on this issue are scarce. Further research on their toxicological, human and public health consequences is urgently required. - Highlights: ► We quantified cer, lanthanum and cadmium concentrations in indoor air. ► Cer and lanthanum concentrations were high in tobacco smoke enriched locations. ► Both elements can be considered as good markers for indoor air quality.

  11. Effects of stress concentration on low-temperature fracture behavior of A356 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Guanghui; Li, Runxia; Li, Rongde

    2016-06-14

    The effect of stress concentration on the dislocation motion, the Si particles and the crack propagation path in A356 alloy at the temperature of 20 °C to −60 °C was analyzed by scanning electron microscope and optical microscope using a series of notched tensile specimens and normal tensile specimens. The results show that the sensitivity of A356 alloy to the stress concentration increases, the tensile strength and yield strength of normal specimens and notched specimens increase, and the elongation shows a decreasing trend with the decrease of test temperature from 20 °C to −60 °C. The yield strength is not affected by the notch, and the tensile strength is sensitive to the stress concentration. Stress concentration leads to a large number of dislocation generation. Local plastic deformation occurred in the stress concentration region during the tensile process firstly. With the stress concentration in the aluminum matrix between the Si phase and the crack further increasing, the distribution of cracks along the Si phase leads to the cracking of aluminum matrix particle.

  12. The effect of couple-stresses on the stress concentration around a moving crack

    Directory of Open Access Journals (Sweden)

    S. Itou

    1981-01-01

    Full Text Available The problem of a uniformly propagating finite crack in an infinite medium is solved within the linearized couple-stress theory. The self-equilibrated system of pressure is applied to the crack surfaces. The problem is reduced to dual integral equations and solved by a series-expansion method. The dynamic stress-intensity factor is computed numerically.

  13. Effect of Heat Stress on Concentrations of Faecal Cortisol Metabolites in Dairy Cows.

    Science.gov (United States)

    Rees, A; Fischer-Tenhagen, C; Heuwieser, W

    2016-06-01

    The negative impact of heat stress on health and productivity of dairy cows is well known. Heat stress can be quantified with the temperature-humidity index (THI) and is defined as a THI ≥ 72. Additionally, animal welfare is affected in cows living under heat stress conditions. Finding a way to quantify heat stress in dairy cows has been of increasing interest over the past decades. Therefore, the objective of this study was to evaluate concentrations of faecal glucocorticoid metabolites [i.e. 11,17-dioxoandrostanes (11,17-DOA)] as an indirect stress parameter in dairy cows without heat stress (DOA 0), with heat stress on a single day (acute heat stress, DOA 1) or with more than a single day of heat stress (chronic heat stress, DOA 2). Cows were housed in five farms under moderate European climates. Two statistical approaches (approach 1 and approach 2) were assessed. Using approach 1, concentrations of faecal 11,17-DOA were compared among DOA 0, DOA 1 and DOA 2 samples regardless of their origin (i.e. cow, unpaired comparison with a one-way anova). Using approach 2, a cow was considered as its own control; that is 11,17-DOA was treated as a cow-specific factor and only paired samples were included in the analysis for this approach (paired comparison with t-tests). In approach 1 (p = 0.006) and approach 2 (p = 0.038), 11,17-DOA values of cows under acute heat stress were higher compared to those of cows without heat stress. Our results also indicate that acute heat stress has to be considered as a confounder in studies measuring faecal glucocorticoid metabolites in cows to evaluate other stressful situations. © 2016 Blackwell Verlag GmbH.

  14. Less-studied TCE: are their environmental concentrations increasing due to their use in new technologies?

    Science.gov (United States)

    Filella, M; Rodríguez-Murillo, J C

    2017-09-01

    The possible environmental impact of the recent increase in use of a group of technology-critical elements (Nb, Ta, Ga, In, Ge and Te) is analysed by reviewing published concentration profiles in environmental archives (ice cores, ombrotrophic peat bogs, freshwater sediments and moss surveys) and evaluating temporal trends in surface waters. No increase has so far been recorded. The low potential direct emissions of these elements, resulting from their absolute low production levels, make it unlikely that the increasing use of these elements in modern technology has any noticeable effect on their environmental concentrations on a global scale. This holds particularly true for those of these elements that are probably emitted in relatively high amounts from other human activities (i.e., coal combustion and non-ferrous smelting), such as In, the most studied element of the group. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    Science.gov (United States)

    Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

  16. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    International Nuclear Information System (INIS)

    Guihua Wang; Ogden, Joan M.; Chang, Daniel P.Y.

    2007-01-01

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x ) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air

  17. Effect of nitrogen concentration and temperature on the critical resolved shear stress and strain rate sensitivity of vanadium

    International Nuclear Information System (INIS)

    Rehbein, D.K.

    1980-08-01

    The critical resolved shear stress and strain rate sensitivity were measured over the temperature range from 77 to 400 0 K for vanadium-nitrogen alloys containing from 0.0004 to 0.184 atom percent nitrogen. These properties were found to be strongly dependent on both the nitrogen concentration and temperature. The following observations were seen in this investigation: the overall behavior of the alloys for the temperature and concentration range studied follows a form similar to that predicted; the concentration dependence of the critical resolved shear stress after subtracting the hardening due to the pure vanadium lattice obeys Labusch's c/sup 2/3/ relationship above 200 0 K and Fleischer's c/sup 1/2/ relationship below 200 0 K; the theoretical predictions of Fleischer's model for the temperature dependence of the critical resolved shear stress are in marked disagreement with the behavior found; and the strain rate sensitivity, par. delta tau/par. deltaln γ, exhibits a peak at approximately 100 0 K that decreases in height as the nitrogen concentration increases. A similar peak has been observed in niobium by other investigators but the effect of concentration on the peak height is quite different

  18. Relationship between depression anxiety stress scale (DASS) and urinary hydroxyproline and proline concentrations in hospital workers.

    Science.gov (United States)

    Lee, Keou Won; Kim, Soo Jeong; Park, Jae Beom; Lee, Kyung Jong

    2011-01-01

    Although increased reactive oxygen species (ROS) is caused by stress accelerates collagen degradation, there was no data on the relationship between stress and urinary hydroxyproline (Hyp) and proline (Pro), a good marker of collagen degradation. The purpose of this study was to evaluate the relationship between depression, anxiety, and stress (DAS) and concentrations of urinary Hyp and Pro. 97 hospital employees aged 20 to 58 were asked to fill out comprehensive self-administrated questionnaires containing information about their medical history, lifestyle, length of the work year, shift-work and DAS. depression anxiety stress scale (DASS) was applied to evaluate chronic mental disorders. Urine samples were analyzed using high performance liquid chromatography (HPLC) with double derivatization for the assay of hydroxyproline and proline. The mean value of Hyp and Pro concentration in all subjects was 194.1 ± 113.4 μmol/g and 568.2 ± 310.7 μmol/g. DASS values and urinary Pro concentrations were differentiated by sex (female > male, p others, p < 0.05). In the stepwise multiple linear regressions, urinary Hyp and Pro concentrations were influenced by stress (Adjusted r2 = 0.051) and anxiety and job (Adjusted r2 = 0.199), respectively. We found that stress and anxiety were correlated with urinary Hyp and Pro concentrations. To identifying a definite correlation, further study in large populations will be needed.

  19. Event terms in the response spectra prediction equation and their deviation due to stress drop variations

    Science.gov (United States)

    Kawase, H.; Nakano, K.

    2015-12-01

    We investigated the characteristics of strong ground motions separated from acceleration Fourier spectra and acceleration response spectra of 5% damping calculated from weak and moderate ground motions observed by K-NET, KiK-net, and the JMA Shindokei Network in Japan using the generalized spectral inversion method. The separation method used the outcrop motions at YMGH01 as reference where we extracted site responses due to shallow weathered layers. We include events with JMA magnitude equal to or larger than 4.5 observed from 1996 to 2011. We find that our frequency-dependent Q values are comparable to those of previous studies. From the corner frequencies of Fourier source spectra, we calculate Brune's stress parameters and found a clear magnitude dependence, in which smaller events tend to spread over a wider range while maintaining the same maximum value. We confirm that this is exactly the case for several mainshock-aftershock sequences. The average stress parameters for crustal earthquakes are much smaller than those of subduction zone, which can be explained by their depth dependence. We then compared the strong motion characteristics based on the acceleration response spectra and found that the separated characteristics of strong ground motions are different, especially in the lower frequency range less than 1Hz. These differences comes from the difference between Fourier spectra and response spectra found in the observed data; that is, predominant components in high frequency range of Fourier spectra contribute to increase the response in lower frequency range with small Fourier amplitude because strong high frequency component acts as an impulse to a Single-Degree-of-Freedom system. After the separation of the source terms for 5% damping response spectra we can obtain regression coefficients with respect to the magnitude, which lead to a new GMPE as shown in Fig.1 on the left. Although stress drops for inland earthquakes are 1/7 of the subduction

  20. Changes of electronic structure of SnTe due to high concentration of Sn vacancies

    International Nuclear Information System (INIS)

    Masek, J.; Nuzhnyj, D.N.

    1997-01-01

    Non-stoichiometric Sn 1-y Te is a strongly degenerated n-type semiconductor. This is important for understanding unusual features of magnetic behaviour of Sn 1-x Gd x Te where the relative positions of the Fermi energy and the atomic d-level of Gd govern the exchange coupling.The influence of the Sn vacancies on the band structure cannot be neglect if their concentration reaches a few atomic percent. We address this problem by using a tight-binding coherent potential approach and show that although the character of the bands remains unchanged, they are modified so that ε d can come out above the heavy-hole band. (author)

  1. Preliminary Estimation of Radioactive Cesium Concentration due to Hypothetical Accident in East Sea

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung-Il; Kim, Sora; Park, Kihyun; Suh, Kyung-suk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The sea has no large islands, bays or capes. Its water balance is mostly determined by the inflow (Korea Strait) and outflow (Tsugaru Strait and Soya Strait) through the straits connecting it to the neighboring seas and Pacific Ocean. All of the Korean nuclear power plants are located in the coastal area, 3 sites in the east coast and 1 site in the west coast. So the Korean nuclear power plants there may be possibility that such dangerous substances spread out of the East Sea. The East Sea is a fertile fishing ground for surrounding counties. The environmental radionuclides concentration estimation is important for fish and sea plants may be contaminated by those radioactive materials. In order to simplify the problem, the experiment has been considered the many simplifying assumptions. The bed sediments are uniform over all the model domain, using the monthly mean ocean current data set and ignored effect of the facilities for damage preventions.

  2. Residual stresses due to weld repairs, cladding and electron beam welds and effect of residual stresses on fracture behavior. Annual report, September 1, 1977--November 30, 1978

    International Nuclear Information System (INIS)

    Rybicki, E.F.

    1978-11-01

    The study is divided into three tasks. Task I is concerned with predicting and understanding the effects of residual stresses due to weld repairs of pressure vessels. Task II examines residual stresses due to an electron beam weld. Task III addresses the problem of residual stresses produced by weld cladding at a nozzle vessel intersection. The objective of Task I is to develop a computational model for predicting residual stress states due to a weld repair of pressure vessel and thereby gain an understanding of the mechanisms involved in the creation of the residual stresses. Experimental data from the Heavy Section Steel Technology (HSST) program at Oak Ridge National Laboratories (ORNL) is used to validate the computational model. In Task II, the residual stress model is applied to the case of an electron beam weld of a compact tension freacture specimen. The results in the form of residual stresses near the weld are then used to explain unexpected fracture behavior which is observed in the testing of the specimen. For Task III, the residual stress model is applied to the cladding process used in nozzle regions of nuclear pressure vessels. The residual stresses obtained from this analysis are evaluated to determine their effect on the phenomena of under-clad cracking

  3. Stress reaction in crayfish: chlorides help to withstand stress in high nitrite concentration conditions – preliminary study

    Directory of Open Access Journals (Sweden)

    Kozák P.

    2011-06-01

    Full Text Available A non-invasive method of recording cardiac activity (heart rate – HR and stress reaction (stress index – SI was used to understand the immediate and ongoing stress reaction of crayfish to the chemical stimuli. This method detects changes in the shape and amplitude parameters of the response to the stress factors, which characterized the crayfish functional state. Experimental animals (Astacus leptodactylus were divided to the two groups with (400 mg·L-1 Cl− and without added chlorides and then exposed to a stepwise increased level of nitrite to the final (sublethal-lethal concentration of 60 mg·L-1 N-NO\\hbox{$_{2}^{-}$}−2 within 24 hours. The course of crayfish reaction was evident and provided information about their reaction to the sublethal-lethal concentration over time. As expected, a less prominent stress reaction was detected in the group with chlorides. The non-invasive method successfully evaluated the sensing of chemical stimuli in water through HR and SI changes.

  4. Pre-analytical variation in glucose concentration due to atmospheric temperature and clot in blood specimens

    International Nuclear Information System (INIS)

    Butt, T.; Masud, K.; Khan, J.A.; Bhatti, M.S.

    2016-01-01

    Objective: To determine the effect of temperature and contact of clot with serum on laboratory results of glucose concentration in blood. Study Design: Quasi-experimental study. Place and Duration of Study: December 2014 to August 2015 at the laboratory of Shoaib Hospital, Fateh Jang, Attock Pakistan. Material and Methods: Samples were collected for estimation of blood glucose (Random) concentration from patients reporting to the hospital. Blood specimens (n=94) of such volunteers were analyzed for glucose level. Each sample was put up in five tubes. When the blood clotted the serum from tube-1 was analyzed for glucose level within 30 minutes. In tube-2 and tube-3 serum was kept for 24 hours at room temperature and refrigerator temperature respectively before glucose estimation. In tube-4 and tube-5 serum was not separated from clot and kept at room temperature and refrigerator temperature respectively before glucose estimation. The value of tube 1 was taken as reference value for comparison with other parts of the specimen. The equipment used for blood glucose level estimation was semi auto chemistry analyzer (Rayto, China). The kit used for analysis was Glucose - Liquizyme (Germany). Results: The difference between the mean reference value (tube-1) and refrigerated serum without clot (tube-3) was 4.63 mg/100 ml while that of unrefrigerated portion (tube-2) had a difference of 10.68 mg/100 ml. The mean of unrefrigerated (tube-4) and refrigerated (tube-5) portions of serum kept with the clot had difference of 42.05 mg/100 ml and 25.84 mg/100 ml respectively. The fall in the blood glucose level in all (n=94) the samples in the tube number 3 (serum separated and kept at refrigerated temperature) was 4.63 mg/100 ml +- 3.68 (Mean +- SD) and it ranged from 0 to 20 mg/100 ml whereas fall was maximum in the tube number 4 (serum with clotted blood and kept at room temperature) was 42.04 mg/100 ml +- 10.61 (Mean +- SD) and it ranged from 13 to 82 mg/100 ml. The sample in

  5. Low mercury concentration produces vasoconstriction, decreases nitric oxide bioavailability and increases oxidative stress in rat conductance artery.

    Directory of Open Access Journals (Sweden)

    Núbia Belem Lemos

    Full Text Available Mercury is an environmental pollutant that reduces nitric oxide (NO bioavailability and increases oxidative stress, having a close link with cardiovascular diseases, as carotid atherosclerosis, myocardial infarction, coronary heart disease and hypertension. One of the main sites affected by oxidative stress, which develops atherosclerosis, is the aorta. Under acute exposure to low mercury concentrations reactive oxygen species (ROS production were only reported for resistance vessels but if low concentrations of mercury also affect conductance arteries it is still unclear. We investigated the acute effects of 6 nM HgCl(2 on endothelial function of aortic rings measuring the reactivity to phenylephrine in rings incubated, or not, with HgCl(2 for 45 min, the protein expression for cyclooxygenase 2 (COX-2 and the AT1 receptor. HgCl(2 increased Rmax and pD2 to phenylephrine without changing the vasorelaxation induced by acetylcholine and sodium nitroprusside. Endothelial damage abolished the increased reactivity to phenylephrine. The increase of Rmax and pD2 produced by L-NAME was smaller in the presence of HgCl(2. Enalapril, losartan, indomethacin, furegrelate, the selective COX-2 inhibitor NS 398, superoxide dismutase and the NADPH oxidase inhibitor apocynin reverted HgCl(2 effects on the reactivity to phenylephrine, COX-2 protein expression was increased, and AT1 expression reduced. At low concentration, below the reference values, HgCl(2 increased vasoconstrictor activity by reducing NO bioavailability due to increased ROS production by NADPH oxidase activity. Results suggest that this is due to local release of angiotensin II and prostanoid vasoconstrictors. Results also suggest that acute low concentration mercury exposure, occurring time to time could induce vascular injury due to endothelial oxidative stress and contributing to increase peripheral resistance, being a high risk factor for public health.

  6. Stress Concentrations.

    Science.gov (United States)

    1982-09-01

    a joJo p~ ~qJO iju;~33 oa~u UO~u~aUuo3-s;JS I I awnh!d pu1 IuwLaqdsawq aqlI i~ pjO3U u L1 t 3AIWSOd NANOHS 3AIIISOd NAMONS SQOl Q3liddV 3Y 1 0 SOV0I...caesgi 30332 50S King Avenue Drxel University Clmu.Oi 30 Department of mechanical enginserieg prof essor Graham.?. Carey ClmuOi 30 and mechanics

  7. Influence of structural parameter included in nonlocal rock mass model on stress concentration around circular tunnel

    Science.gov (United States)

    Lavrikov, SV; Mikenina, OA; Revuzhenko, AF

    2018-03-01

    A model of elastic body, including local curvature of elementary volume, is matched with a nonlocal model with a linear structural parameter in the differential approximation. The problem on deformation of rock mass around a circular cross section tunnel is solved numerically. The contours of the calculated stresses are plotted. It is shown that inclusion of local bends in the model results in expansion of influence zone of the tunnel and reduces stress concentration factor at the tunnel boundary.

  8. Immunoelectron microscopic studies on metallothionein induction in Nile cichlid due to heavy metal stress

    International Nuclear Information System (INIS)

    Chatterjee, S.; Singh, L.; Das, T.K.; Mukhopadhyay, S.K.

    2010-01-01

    Heavy metals are important environmental pollutants and many of them are toxic even in low concentrations. The uncontrolled input of such elements in milieu is undesirable because once accumulated, are hard to remove. The release of toxic metals in biologically available forms by human activity may damage or alter both natural and man-made ecosystems. The cellular adaptation to toxicity of metals is one of the important factors for organisms living in the stressful conditions. The major type of cellular effect at the cytoplasmic level involves binding of metals through specific metal binding proteins. One of these metalloproteins is metallothionein (MT), MT is a low-molecular-weight (6-7 kDa) cysteine rich protein ubiquitous in the animal kingdom and can bind with essential (Cu + and Zn 2+ ) and nonessential (Cd 2+ , Hg 2+ and Ag + ) metals with a high thermodynamic and low kinetic stability. Again, the induction of MT by other heavy metals such as Cr, Mn and Pb was also reported by several workers

  9. Isopleths of surface air concentration and surface air kerma rate due to a radioactive cloud released from a stack (3)

    International Nuclear Information System (INIS)

    Tachibana, Haruo; Kikuchi, Masamitsu; Sekita, Tsutomu; Yamaguchi, Takenori

    2004-06-01

    This report is a revised edition of 'Isopleths of Surface Air Concentration and Surface Air Absorbed Dose Rate due to a Radioactive Cloud Released from a Stack(II) '(JAERI-M 90-206) and based on the revised Nuclear Safety Guidelines reflected the ICRP1990 Recommendation. Characteristics of this report are the use of Air Karma Rate (Gy/h) instead of Air Absorbed Dose Rate (Gy/h), and the record of isopleths of surface air concentration and surface air karma rate on CD-ROM. These recorded data on CD-ROM can be printed out on paper and/or pasted on digital map by personal computer. (author)

  10. Stress concentration factors for an internally pressurized circular vessel containing a radial U-notch

    International Nuclear Information System (INIS)

    Carvalho, E.A. de

    2005-01-01

    This paper evaluates the stress concentration factors for an internally pressurized cylinder containing a radial U-notch along its length. This work studies the cases where the external to internal radius ratio (Ψ) is equal to 1.26, 1.52, 2.00, and 3.00 and the notch radius to internal radius ratio (Φ) is fixed and equal to 0.026. The U-notch depth varies from 0.1 to 0.6 of the wall thickness. Results are also presented for a fixed size semi-circular notch. Hoop stresses at the external wall are presented, showing regions where the stress matches the nominal one and the favourable places to install strain sensors. The finite element method is used to determine the stress concentration factors (K t ) for the above described situations and for a special case where a varying semi-circular notch is present with Ψ=3.00. This notch depth varies from 0.013 to 0.3 of the wall thickness. It is pointed out that even relatively small notches introduce large stress concentrations and disrupt the hoop stress distribution all over the cross section. Results are also compared to an example found in the literature for semi-circular notches and K t curves for both cases present the same shape

  11. Numerical Analysis of Stress Concentration in Isotropic and Laminated Plates with Inclined Elliptical Holes

    Science.gov (United States)

    Khechai, Abdelhak; Tati, Abdelouahab; Belarbi, Mohamed Ouejdi; Guettala, Abdelhamid

    2018-03-01

    The design of high-performance composite structures frequently includes discontinuities to reduce the weight and fastener holes for joining. Understanding the behavior of perforated laminates is necessary for structural design. In the current work, stress concentrations taking place in laminated and isotropic plates subjected to tensile load are investigated. The stress concentrations are obtained using a recent quadrilateral finite element of four nodes with 32 DOFs. The present finite element (PE) is a combination of two finite elements. The first finite element is a linear isoparametric membrane element and the second is a high precision Hermitian element. One of the essential objectives of the current investigation is to confirm the capability and efficiency of the PE for stress determination in perforated laminates. Different geometric parameters, such as the cutout form, sizes and cutout orientations, which have a considerable effect on the stress values, are studied. Using the present finite element formulation, the obtained results are found to be in good agreement with the analytical findings, which validates the capability and the efficiency of the proposed formulation. Finally, to understand the material parameters effect such as the orientation of fibers and degree of orthotropy ratio on the stress values, many figures are presented using different ellipse major to minor axis ratio. The stress concentration values are considerably affected by increasing the orientation angle of the fibers and degree of orthotropy.

  12. Relationships between soluble sugar concentrations in roots and ecosystem stress for first-year sugar maple seedlings

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, J.W.; Reed, D.D.; Jurgensen, M.F.; Mroz, G.D.; Bagley, S.T. [Michigan Technological University, Houghton, MI (United States). School of Forestry and Wood Products

    1996-03-01

    Accumulation of reducing sugars (i.e. glucose and fructose) in plant roots has been consistently correlated with forest dieback and decline and, therefore, has potential as a biological indicator of ecosystem stress. In this study, the relationships between acidic deposition and `natural` (temperature, mycorrhizae, and nutrition) factors with first-year sugar maple seedling root sugar concentrations and growth were assessed in two sugar maple dominated forests in Michigan. Seedlings at the southern site (Wellston) had greater root growth, phosphorus, total sugar, and sucrose concentrations in roots, but lower reducing sugar concentration in roots. In addition, percent root length colonized by vesicular-arbuscular mycorrhizal fungi was less than that found for seedlings growing at the northern site (Alberta). Throughfall deposition of nitrate, sulfate, and hydrogen ions was not significantly correlated with seedling total or reducing sugar concentration. Total sugar concentration in seedling roots was positively correlated with air and soil temperatures at the southern site, but not at the northern site. Seedling tissue phosphorus concentration was correlated with total sugars at both sites, with sucrose at the southern site, and reducing sugars at the northern site. Mycorrhizal colonization rates at the Alberta site were positively correlated with reducing sugar concentration in seedling roots and negatively correlated with sucrose concentration. The results suggest that differences in seedling root sugar concentrations in these two forests are related to seedling root growth and are most likely due to ecological variables, such as available soil phosphorus, temperature, and growing season length through some complex interaction with mycorrhizae rather than acidic deposition stress. 56 refs., 3 figs.

  13. Running Reduces Uncontrollable Stress-Evoked Serotonin and Potentiates Stress-Evoked Dopamine Concentrations in the Rat Dorsal Striatum.

    Directory of Open Access Journals (Sweden)

    Peter J Clark

    Full Text Available Accumulating evidence from both the human and animal literature indicates that exercise reduces the negative consequences of stress. The neurobiological etiology for this stress protection, however, is not completely understood. Our lab reported that voluntary wheel running protects rats from expressing depression-like instrumental learning deficits on the shuttle box escape task after exposure to unpredictable and inescapable tail shocks (uncontrollable stress. Impaired escape behavior is a result of stress-sensitized serotonin (5-HT neuron activity in the dorsal raphe (DRN and subsequent excessive release of 5-HT into the dorsal striatum following exposure to a comparatively mild stressor. However, the possible mechanisms by which exercise prevents stress-induced escape deficits are not well characterized. The purpose of this experiment was to test the hypothesis that exercise blunts the stress-evoked release of 5-HT in the dorsal striatum. Changes to dopamine (DA levels were also examined, since striatal DA signaling is critical for instrumental learning and can be influenced by changes to 5-HT activity. Adult male F344 rats, housed with or without running wheels for 6 weeks, were either exposed to tail shock or remained undisturbed in laboratory cages. Twenty-four hours later, microdialysis was performed in the medial (DMS and lateral (DLS dorsal striatum to collect extracellular 5-HT and DA before, during, and following 2 mild foot shocks. We report wheel running prevents foot shock-induced elevation of extracellular 5-HT and potentiates DA concentrations in both the DMS and DLS approximately 24 h following exposure to uncontrollable stress. These data may provide a possible mechanism by which exercise prevents depression-like instrumental learning deficits following exposure to acute stress.

  14. Red blood cells sensitivity to oxidative stress in the presence of low concentrations of uranium compound

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, O.G. [Institute of Biology, Komi Scientific Centre, Ural Branch of Russian Academy of Sciences, 167982, Syktyvkar (Russian Federation)

    2014-07-01

    Uranium is a natural radioactive element widespread in biosphere. There are a few works that examined cellular and molecular mechanisms of uranium toxicity. Red blood cells are classical model to investigate toxicity mechanisms on cell membrane system. The aim of present work is to study the effect of uranyl ion in nano-molar concentrations on erythrocytes sensitivity (in vitro) to factors provoking acute oxidative stress. Uranyl ions were added to suspension of mice red blood cells in PBS as UO{sub 2}Cl{sub 2} solution. Samples were incubated in a thermostatic shaker at 37 deg. C during 3-5 hours. Than acute oxidative stress was induced by H{sub 2}O{sub 2} (0.9 mM) or AAPH (5 mM) solutions. Destabilization of the membrane was induced by nonionic detergent Triton X-100. The hemolysis degree and the content of LPO secondary products reacting with 2-thiobarbituric acid in the incubation mixture were determined spectrophotometrically. The ratio of hemoglobin various forms (oxyHb, metHb and ferrylHb) was calculated taking into account extinction coefficients. It was shown that uranyl chloride enhances cell sensitivity to nonionic detergent Triton X-100 effects, indicating alterations of membrane acyl chain order due to contact with the radionuclide ions. Uranium exposure also caused an increase in the cell sensitivity to the AAPH effects, resulted in a decrease in red cell survival rate, a sharp increase in accumulation of hemoglobin oxidation products and a slight increase in the concentration of LPO secondary products. Thus, uranyl ions change physicochemical properties of the erythrocyte membranes that resulted in increased sensitivity to effects of peroxyl radicals formed by thermal decomposition of AAPH. On the contrary, use of another source of free radicals - H{sub 2}O{sub 2} - after uranyl ions exposure resulted in marked decrease of oxidative hemolysis, inhibition of LPO and hemoglobin oxidation. Since the uranium chemical properties similar to properties of

  15. Interstitial relaxations due to hydrostatic stress in niobium--oxygen alloys

    International Nuclear Information System (INIS)

    Tewari, S.N.

    1974-01-01

    Experimental investigations of the anelastic relaxation induced by hydrostatic stress in the range from ambient to 81 ksi were made for niobium--oxygen alloys. The anelastic responses, both for the pressurization and the pressure release experiments, were followed by measuring the relative length change between the oxygenated niobium sample and a pure niobium frame with a precision of about 2 A. The relaxation spectrum observed was shown to be made up of three distinct relaxations with unique relaxation times and strengths. The pressure dependence of the relaxation times gave the apparent activation volume for these relaxations of the order of 4 cm 3 /mole. The relaxations were observed to have relaxation strengths of the order of 10 -4 which were found to be independent of pressure up to 81 ksi. The relaxation times for these relaxations were found to occur in the same general temperature range as those for the Snoek relaxations of oxygen clusters in niobium. The temperature dependence of the relaxation times, however, gave activation energies of about 11 to 15 kcal/mole, as compared with roughly 27 to 29 kcal/mole for the Snoek relaxation of oxygen clusters in niobium. Several possible models for these relaxations were developed, however, none could predict the observed temperature dependence. The best interpretation of the data is that due to some anomalous competing relaxation the actual temperature dependence of these relaxations could not be observed. A completely self-consistent analysis is found which is based upon this assumption. (U.S.)

  16. Oxidative stress responses of submerged macrophyte Vallisneria asiatica to different concentrations of cyanobacteria

    Science.gov (United States)

    Kang, Caixia; Kuba, Takahiro; Hao, Aimin; Iseri, Yasushi; Li, Chunjie; Zhang, Zhenjia

    2015-03-01

    In a 10-day aquarium experiment, this investigation examines macrophyte restoration in eutrophic Lake Taihu, the physiological effects of different plant biomass levels and of increasing natural cyanobacterial concentrations on a submerged macrophyte, Vallisneria asiatica. Cyanobacterial stress suppressed the superoxide dismutase (SOD) activity of the plant's leaves and induced the catalase (CAT) and peroxidase (POD) activities of its roots. The soluble protein content in V. asiatica decreased with an increase in natural cyanobacterial concentrations, whereas the malonaldehyde (MDA) increased significantly at chlorophyll a (Chl a) concentrations of 222 and 262 μg/L in water. V. asiatica adapted to the stress caused by cyanobacterial concentrations by adjusting its antioxidant defense system to remove the excessive reactive oxygen species when the algal Chl a concentration was >109 μg/L. Additionally, high biomass of V. asiatica (2 222 g FW/m2) can inhibit the reproduction of cyanobacteria more significantly than low biomass (1 111 g FW/m2). High biomass of V. asiatica increased the oxidative stress in an individual plant when the initial Chl a concentration in the water reached 222 and 262 μg/L, as expressed by the increased MDA in leaves, compared with low biomass of V. asiatica. This provides a basis for controlling cyanobacterial concentrations and V. asiatica biomass for the recovery of V. asiatica in eutrophic Lake Taihu.

  17. Relaxation of Si-SiO2 interfacial stress in bipolar screen oxides due to ionizing radiation

    International Nuclear Information System (INIS)

    Witczak, S.C.; Galloway, K.F.; Schrimpf, R.D.; Suehle, J.S.

    1995-01-01

    Current gain degradation due to ionizing radiation in complementary single-crystalline emitter bipolar transistors was found to grow progressively worse upon subjecting the transistors to repeated cycles of radiation exposure and high-temperature anneal. The increase in radiation sensitivity is independent of the emitter polarity or geometry and is most dramatic between the first and second radiation and anneal cycles. In parallel with the current gain measurements, samples from a monitor wafer simulating the screen oxide region above the extrinsic base in the npn transistors were measured for mechanical stress while undergoing similar cycles of irradiation and anneal. The oxide on the monitor wafer consisted of a 45 nm thermal layer and a 640 nm deposited layer. The results indicate that ionizing radiation helped relieve compressive stress at the Si surface. The magnitude of the stress change due to radiation is smaller than the stress induced by the emitter contact metallization followed by a post-metallization anneal. Correlation of radiation sensitivity in the bipolar transistors and mechanical stress in the monitor wafer suggests that mechanical stress may be influential in determining the radiation hardness of bipolar transistors and lends validation to previously reported observations that Si-SiO 2 interfaces are increasingly more susceptible to radiation damage with decreasing Si compressive stress. Possible mechanisms for the observed changes in stress and their effect on the radiation sensitivity of the bipolar transistors are discussed

  18. Simulation of stresses, residual stresses, and distortion in stepped cylinders of AISI 4140 due to martensitical hardening by immersion cooling

    Energy Technology Data Exchange (ETDEWEB)

    Ehlers, M.; Mueller, H.; Loehe, D. [Karlsruhe Univ. (Germany). Inst. for Materials Science and Engineering I

    1999-09-01

    Heat treatment improves mechanical properties of steel parts, but also causes residual stresses and distortion. Stresses and deformation occurring during heat treatment can not be measured in-situ with appropriate temporal and spatial resolution. In order to evaluate the processes occurring in the workpiece during quenching as well as the residual stresses and distortions, numerical methods have to be used. Heat conduction, phase transformations, and mechanical behaviour of the material as well as the couplings between the processes such as transformation plasticity have to be modeled for the simulation of steel hardening. Temperature and phase dependent properties (including TTT-data) have to incorporated into calculations. One of the major factors determining the evolution of stress and deformation is the heat-transfer coefficient between component and quenching medium. For vapourizing liquids, heat transfer depends on temperature and location. But heat transfer is not only influenced by the quenchant but also by part geometry and size. Stepped cylinders of AISI 4140 steel were quenched in water and oil. Both experimental measurements and numerical calculations were carried out. The variation of dive-in direction strongly influences the rewetting of the specimen surface and therefore the cooling behaviour, stress and deformation evolution, and resultant residual stresses and distortion. Excellent agreement is obtained between calculated and experimental results. (orig.)

  19. Effects of fiber ellipticity and orientation on dynamic stress concentrations in porous fiber-reinforced composites

    Science.gov (United States)

    Hasheminejad, Seyyed M.; Sanaei, Roozbeh

    2007-11-01

    Interaction of time harmonic fast longitudinal and shear incident plane waves with an elliptical fiber embedded in a porous elastic matrix is studied. The novel features of Biot dynamic theory of poroelasticity along with the classical method of eigen-function expansion and the pertinent boundary conditions are employed to develop a closed form series solution involving Mathieu and modified Mathieu functions of complex arguments. The complications arising due to the non-orthogonality of angular Mathieu functions corresponding to distinct wave numbers in addition to the problems associated with appearance of additional angular dependent terms in the boundary conditions are all avoided by expansion of the angular Mathieu functions in terms of transcendental functions and subsequent integration, leading to a linear set of independent equations in terms of the unknown scattering coefficients. A MATHEMATICA code is developed for computing the Mathieu functions in terms of complex Fourier coefficients which are themselves calculated by numerically solving appropriate sets of eigen-systems. The analytical results are illustrated with numerical examples in which an elastic fiber of elliptic cross section is insonified by a plane fast compressional or shear wave at normal incidence. The effects of fiber cross sectional ellipticity, angle of incidence (fiber two-dimensional orientation), and incident wave polarization (P, SV, SH) on dynamic stress concentrations are studied in a relatively wide frequency range. Limiting cases are considered and fair agreements with well-known solutions are established.

  20. Elevated CSF Corticotropin-Releasing Factor Concentrations in Posttraumatic Stress Disorder

    Science.gov (United States)

    Bremner, J. Douglas; Licinio, Julio; Darnell, Adam; Krystal, John H.; Owens, Michael J.; Southwick, Steven M.; Nemeroff, Charles B.; Charney, Dennis S.

    2011-01-01

    Objective Corticotropin-releasing factor (CRF) and somatostatin both play important roles in mediating responses to acute and chronic stress. The purpose of this study was to measure CSF concentrations of CRF and somatostatin in patients with chronic combat-related post-traumatic stress disorder (PTSD) and comparison subjects. Method Lumbar punctures for collection of CSF were performed in Vietnam combat veterans with PTSD (N=11) and comparison subjects (N=17). CSF concentrations of CRF and somatostatin were compared between the two groups. Results CSF concentrations of CRF were higher in the PTSD patients than in the comparison subjects (mean=29.0 pg/ml, SD=7.8, versus mean=21.9 pg/ml, SD=6.0). This group difference remained significant after covariance for age. CSF somatostatin concentrations in PTSD patients were higher than those of the comparison subjects (mean=19.9 pg/ml, SD=5.4, versus mean=13.7 pg/ml, SD=8.0). However, covarying for age reduced the level of significance. Conclusions Higher CSF CRF concentrations in patients with PTSD may reflect alterations in stress-related neurotransmitter systems. The higher CSF CRF concentrations may play a role in disturbances of arousal in patients with PTSD. PMID:9137116

  1. Structural transformations in Mn2NiGa due to residual stress

    International Nuclear Information System (INIS)

    Singh, Sanjay; Maniraj, M.; D'Souza, S. W.; Barman, S. R.; Ranjan, R.

    2010-01-01

    Powder x-ray diffraction study of Mn 2 NiGa ferromagnetic shape memory alloy shows the existence of a 7M monoclinic modulated structure at room temperature (RT). The structure of Mn 2 NiGa is found to be highly dependent on residual stress. For higher stress, the structure is tetragonal at RT, and for intermediate stress it is 7M monoclinic. However, only when the stress is considerably relaxed, the structure is cubic, as is expected at RT since the martensitic transition temperature is 230 K.

  2. Blood Biochemistry and Plasma Corticosterone Concentration in Broiler Chickens Under Heat Stress

    Directory of Open Access Journals (Sweden)

    Elvis Alexander Díaz López

    2014-07-01

    Full Text Available High ambient temperatures cause susceptibility to heat stress in broiler chickens, generating metabolic changes. This paper seeks to determine the changes in blood biochemistry and plasma corticosterone concentration, as well as in glucose, total protein, albumin, globulin, sodium, chlorine, potassium, magnesium, phosphorus, and calcium in broiler chickens under chronic heat stress and at ambient temperature conditions at the Colombian Amazonian piedmont. 21-days-old male chickens of two lines were studied, distributed in an unrestricted random design, in a two-factor scheme, with four treatments. Five repetitions per treatment were performed, and 25 animals per experimental unit examined. Broilers were fed a basic diet of corn and soybean meal with 3,100 kcal ME and 19.5% protein until they reached 42 days of age. The line factor had no effect on the evaluated variables (p ≥ 0.05. However, there was statistically significant difference (p ≤ 0.05 in all variables when concentrations of metabolites in broilers under chronic heat stress were compared to those of chickens exposed to ambient temperatures at the Colombian Amazon piedmont. In conclusion, blood biochemistry suffered significant changes under both experimental temperatures, with more physiological detriment in broilers under chronic heat stress. Concentration of corticosterone became the most sensitive and consistent indicator of the physiological condition of chronic heat stress.

  3. Generating false negatives and false positives for As and Mo concentrations in groundwater due to well installation.

    Science.gov (United States)

    Wallis, Ilka; Pichler, Thomas

    2018-08-01

    Groundwater monitoring relies on the acquisition of 'representative' groundwater samples, which should reflect the ambient water quality at a given location. However, drilling of a monitoring well for sample acquisition has the potential to perturb groundwater conditions to a point that may prove to be detrimental to the monitoring objective. Following installation of 20 monitoring wells in close geographic proximity in central Florida, opposing concentration trends for As and Mo were observed. In the first year after well installation As and Mo concentrations increased in some wells by a factor of 2, while in others As and Mo concentrations decreased by a factor of up to 100. Given this relatively short period of time, a natural change in groundwater composition of such magnitude is not expected, leaving well installation itself as the likely cause for the observed concentration changes. Hence, initial concentrations were identified as 'false negatives' if concentrations increased with time or as 'false positives' if concentrations decreased. False negatives were observed if concentrations were already high, i.e., the As or Mo were present at the time of drilling. False positives were observed if concentrations were relatively lower, i.e., As or Mo were present at low concentrations of approximately 1 to 2μg/L before drilling, but then released from the aquifer matrix as a result of drilling. Generally, As and Mo were present in the aquifer matrix in either pyrite or organic matter, both of which are susceptible to dissolution if redox conditions change due to the addition of oxygen. Thus, introduction of an oxidant into an anoxic aquifer through use of an oxygen saturated drilling fluid served as the conceptual model for the trends where concentrations decreased with time. Mixing between drilling fluid and groundwater (i.e., dilution) was used as the conceptual model for scenarios where increasing trends were observed. Conceptual models were successfully tested

  4. Transient thermal stresses due to a zonal heat source moving back and forth over the surface on an infinite plate

    International Nuclear Information System (INIS)

    Sumi, N.; Hetnarski, R.B.

    1989-01-01

    A solution is given for the transient thermal stresses due to a zonal heat source moving back and forth with a constant angular frequency over the surface of an infinite elastic plate. The transient temperature distribution is obtained by using the complex Fourier and Laplace transforms, and the associated thermal stresses are obtained by means of the thermoelastic displacement potential and the Galerkin function. Graphical representations for the solution in dimensionless terms are included in this paper. (orig.)

  5. Hydrocortisone at stress-associated concentrations helps maintain human heart rate variability during subsequent endotoxin challenge.

    Science.gov (United States)

    Rassias, Athos J; Guyre, Paul M; Yeager, Mark P

    2011-12-01

    We evaluated the differential impact of stress-associated vs high pharmacologic concentrations of hydrocortisone pretreatment on heart rate variability (HRV) during a subsequent systemic inflammatory stimulus. Healthy volunteers were randomized to receive placebo (Control) and hydrocortisone at 1.5 μg/kg per minute (STRESS) or at 3.0 μg/kg per minute (PHARM) as a 6-hour infusion. The STRESS dose was chosen to replicate the condition of physiologic adrenal cortical output during acute systemic stress. The PHARM dose was chosen to induce a supraphysiologic concentration of cortisol. The next day, all subjects received 2 ng/kg Escherichia coli endotoxin (lipopolysaccharide). Heart rate variability was analyzed with the statistic approximate entropy (ApEn). A lower ApEn correlates with decreased HRV. At the 3-hour nadir, the decrease in ApEn in the STRESS group was significantly less compared to placebo (P statistically different. We also found that the maximal decrease in ApEn preceded maximal increase in heart rate in all groups. The decrease in R-R interval was maximal at 4 hours, whereas the ApEn nadir was 1 hour earlier at 3 hours. Pretreatment with a stress dose of hydrocortisone but not a higher pharmacologic dose maintained a significantly higher ApEn after endotoxin exposure when compared to a placebo. In addition, decreases in ApEn preceded increases in heart rate. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Investigation of Stress Concentration and Casing Strength Degradation Caused by Corrosion Pits

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2016-01-01

    Full Text Available Downhole casing and tubing are subjected to corrosion in many cases because of the exposure to corrosive environment. A more serious problem is that pitting corrosion occurs in the casing inner surface. Meanwhile, downhole strings are subjected to various forms of mechanical loads, for example, internal pressure load, external collapse load, or both. These loads acting on the corrosion pits will cause stress concentration and degrade the casing strength. Thus, it is essential to evaluate the stress concentration degree reasonably. The SCF (stress concentration factor is usually used to characterize the degree of stress concentration induced by corrosion pits. This paper presented a comparison on the SCFs regarding the analytical method for a single pit and experimental method for double pits. The results show that the SCF of a single pit depends mainly on the depth of the corrosion pit; however, the SCF of the double pits strongly depends on the pits distance. A correction factor of 1.3 was recommended in the double pits SCF prediction model.

  7. Stress in film/substrate system due to diffusion and thermal misfit effects

    International Nuclear Information System (INIS)

    Shao Shanshan; Xuan Fuzhen; Wang Zhengdong; Tu Shantung

    2009-01-01

    The stress in film/substrate systems has been analysed taking into consideration the coupling effects of diffusion and thermal misfit within the framework of Fick's second law. The solution of diffusion-induced stress in a film/substrate system involving the thermal misfit stress feedback is developed. The effects of modulus ratios, diffusivity ratios, thickness ratios of the substrate and the film and the partial molar volume of the diffusing component on the stress distribution in the film/substrate system are then discussed with the help of the finite difference method. Results indicate that the stresses in the film/substrate system vary with diffusion time. Diffusion enhances the magnitudes of film stress when the thermal misfit stress is compressive in the film. Furthermore, the absolute values of stress in the film increase with the increasing modulus ratios of the substrate and film, while they reduce with the increasing partial molar volume of the diffusing component and the diffusivity ratio of the substrate and the film.

  8. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    Science.gov (United States)

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  9. Effects of stress concentrations on the fatigue life of a gamma based titanium aluminide

    International Nuclear Information System (INIS)

    Trail, S.J.; Bowen, P.

    1995-01-01

    S-N curves for a gamma based titanium aluminide alloy of composition Ti-47.2Al-2.1Mn-1.9Nb(at.%)+2TiB 2 (wt.%) have been used to define fatigue life. Effects of residual stress, stressed volume, loading ratio, loading mode, elevated temperature and surface roughness have been considered. Residual tensile stresses and micro-cracking are introduced by Electro Discharge Machining and the fatigue life is reduced slightly compared with polished samples. Notched fatigue tests show a significant notch strengthening effect which increases with increasing stress concentration factor. The fracture surfaces of specimens tested at room temperature reveal fully brittle failure mechanisms and no evidence of stable crack growth is observed. The fatigue life appears, therefore, to be determined predominantly by the number of cycles to crack initiation. At the elevated temperature of 830 C, evidence for some stable fatigue crack growth has been found. Probable sites for crack initiation are addressed

  10. Probabilistic Prognosis of Environmental Radioactivity Concentrations due to Radioisotopes Discharged to Water Bodies from Nuclear Power Plants.

    Science.gov (United States)

    Tomás Zerquera, Juan; Mora, Juan C; Robles, Beatriz

    2017-11-15

    Due to their very low values, the complexity of comparing the contribution of nuclear power plants (NPPs) to environmental radioactivity with modeled values is recognized. In order to compare probabilistic prognosis of radioactivity concentrations with environmental measurement values, an exercise was performed using public data of radioactive routine discharges from three representative Spanish nuclear power plants. Specifically, data on liquid discharges from three Spanish NPPs: Almaraz, Vandellós II, and Ascó to three different aquatic bodies (river, lake, and coast) were used. Results modelled using generic conservative models together with Monte Carlo techniques used for uncertainties propagation were compared with values of radioactivity concentrations in the environment measured in the surroundings of these NPPs. Probability distribution functions were inferred for the source term, used as an input to the model to estimate the radioactivity concentrations in the environment due to discharges to the water bodies. Radioactivity concentrations measured in bottom sediments were used in the exercise due to their accumulation properties. Of all the radioisotopes measured in the environmental monitoring programs around the NPPs, only Cs-137, Sr-90, and Co-60 had positive values greater than their respective detection limits. Of those, Sr-90 and Cs-137 are easily measured in the environment, but significant contribution from the radioactive fall-out due to nuclear explosions in the atmosphere exists, and therefore their values cannot be attributed to the NPPs. On the contrary, Co-60 is especially useful as an indicator of the radioactive discharges from NPPs because its presence in the environment can solely be attributed to the impact of the closer nuclear facilities. All the modelled values for Co-60 showed a reasonable correspondence with measured environmental data in all cases, being conservative in two of them. The more conservative predictions obtained with

  11. Effect of Electrical Discharge Machining on Stress Concentration in Titanium Alloy Holes.

    Science.gov (United States)

    Hsu, Wei-Hsuan; Chien, Wan-Ting

    2016-11-24

    Titanium alloys have several advantages, such as a high strength-to-weight ratio. However, the machinability of titanium alloys is not as good as its mechanical properties. Many machining processes have been used to fabricate titanium alloys. Among these machining processes, electrical discharge machining (EDM) has the advantage of processing efficiency. EDM is based on thermoelectric energy between a workpiece and an electrode. A pulse discharge occurs in a small gap between the workpiece and electrode. Then, the material from the workpiece is removed through melting and vaporization. However, defects such as cracks and notches are often detected at the boundary of holes fabricated using EDM and the irregular profile of EDM holes reduces product quality. In this study, an innovative method was proposed to estimate the effect of EDM parameters on the surface quality of the holes. The method combining the finite element method and image processing can rapidly evaluate the stress concentration factor of a workpiece. The stress concentration factor was assumed as an index of EDM process performance for estimating the surface quality of EDM holes. In EDM manufacturing processes, Ti-6Al-4V was used as an experimental material and, as process parameters, pulse current and pulse on-time were taken into account. The results showed that finite element simulations can effectively analyze stress concentration in EDM holes. Using high energy during EDM leads to poor hole quality, and the stress concentration factor of a workpiece is correlated to hole quality. The maximum stress concentration factor for an EDM hole was more than four times that for the same diameter of the undamaged hole.

  12. 210Po and 210Pb concentration of cigarettes traded in Hungary and their estimated dose contribution due to smoking

    International Nuclear Information System (INIS)

    Kovacs, Tibor; Somlai, Janos; Nagy, Katalin; Szeiler, Gabor

    2007-01-01

    It is known that tobacco leaves may contain 210 Pb and 210 Po in significant concentrations. The cumulative alpha-radiation dose due to the radioactive content of inhaled cigarette smoke and the increasing number of lung cancer cases explain the importance of the investigation. The present study investigated the activity concentrations of these two radionuclides in 29 Hungarian cigarette samples. The relation between 210 Po/ 210 Pb activity and nicotine/tar content of these cigarettes was also examined. 210 Po was determined by alpha spectrometry using a PIPS detector after chemical leaching and spontaneous deposition of 210 Po on a high nickel-content (25%) stainless steel disk. The 210 Pb activity was calculated from the 210 Po originated from the decay of 210 Pb after a waiting period of eight months. The 210 Po activity concentrations of the measured types of cigarettes ranged from 10.0 to 33.5 mBq/cigarette, and the activity of 210 Pb varied from 9.6 to 32.5 mBq/cigarette. The average annual committed effective dose is estimated to be 185.6±70.6μSv/y and 58.7±22.7μSv/y due to cigarette smoking (20 cigarettes/day) for 210 Po and 210 Pb, respectively

  13. The effect of acute physical and mental stress on soluble cellular adhesion molecule concentration.

    Science.gov (United States)

    Crabb, E Blake; Franco, R Lee; Caslin, Heather L; Blanks, Anson M; Bowen, Mary K; Acevedo, Edmund O

    2016-07-15

    This study investigated the impact of acute physical and mental stress on serum concentrations of vascular cell adhesion molecule (VCAM)-1 and CX3CL1/fractalkine. Male volunteers (n=20; 21.3±0.55years of age) completed a graded treadmill test to exhaustion and a 20-minute mental stress task (Stroop Color-Word Test, mental arithmetic) on separate, non-consecutive days. Heart rate (HR) was measured at baseline and throughout exercise and mental stress. Blood was collected at baseline (PRE), immediately following (POST) and 30min after (POST30) exercise and mental stress. Soluble VCAM-1 and fractalkine were quantified in participant serum via enzyme-linked immunosorbent assays. Both treadmill exercise and the mental stress task significantly increased participant HR; although, exercise resulted in a substantially greater increase in participant HR compared to mental stress (197.82±11.99 vs. 38.67±3.10% [pstress task did not significantly alter serum VCAM-1 or fractalkine at any time point. In conclusion, maximal aerobic exercise results in a significant elevation of the soluble adhesion molecules VCAM-1 and fractalkine in the serum of adult males that does not occur following laboratory-induced mental stress. The findings of the current investigation may suggest a novel protective role for acute aerobic exercise in vascular health via exercise-induced CAM proteolysis. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. A finite element elastic-plastic analysis of residual stresses due to clad welding in reactor vessels

    International Nuclear Information System (INIS)

    Buchalet, C.; Riccardella, P.C.

    1972-01-01

    Residual stresses due to weld deposited cladding on the inside of a typical Westinghouse pressurized water reactor vessel are investigated using an axisymmetric finite element elastic-plastic analysis. At the beginning of the analysis, one head of the weld cladding is assumed to lie on the reactor vessel wall at melting temperature (2600degF), but in the solid phase, while the vessel remains at 300degF (preheat temperature). All material properties used in the calculations are taken as temperature-dependent. Temperature profiles are obtained in the cladding and base metal at several discrete time intervals. These temperatures profiles are used to obtain the stress distribution for the same time intervals. Residual hoop tensile stresses of approximately 25 ksi were found to exist in the cladding. Peak tensile stresses in the hoop direction occur in the base metal near the cladding interface and reach a value of 60 ksi at the end of the transient. The tensile stress decreases very rapidly through the thickness of the base metal and becomes insignificant at about two inches from the inside surface. In order to lower residual stresses, a post-weld heat treatment is performed by uniformly heating the vessel to 1100degF, holding at that temperature for a specified period of time and then cooling slowly. The analysis shows that after this treatment, the peak stresses in the base metal decrease from 60 ksi to 32 ksi, while the stress in the cladding does not change significantly. (author)

  15. Dynamic stress relaxation due to cyclic variation of strain at elevated temperature

    International Nuclear Information System (INIS)

    Suzuki, F.

    1975-01-01

    The relaxation of stress which occurs when low amplitude alternating strains are superimposed on constant mean total strains is studied in this paper. Experiments were carried out on a 0.16 per cent carbon steel and an AISI 347 stainless steel at 450 0 C and 650 0 C respectively in which the decrease of axial mean stress was measured as a function of time. When even a low amplitude alternating strain was applied, the rate of stress relaxation was observed to increase. Analytical predictions based on creep and static relaxation data show fairly good agreement with experiments in the period corresponding to transient creep. (author)

  16. Potential of future seismogenesis in Hebei Province (NE China) due to stress interactions between strong earthquakes

    Science.gov (United States)

    Karakostas, Vassilios; Papadimitriou, Eleftheria; Jin, Xueshen; Liu, Zhihui; Paradisopoulou, Parthena; He, Zhang

    2013-10-01

    Northeast China, a densely populated area, is affected by intense seismic activity, which includes large events that caused extensive disaster and tremendous loss of life. For contributing to the continuous efforts for seismic hazard assessment, the earthquake potential from the active faults near the cities of Zhangjiakou and Langfang in Hebei Province is examined. We estimate the effect of the coseismic stress changes of strong (M ⩾ 5.0) earthquakes on the major regional active faults, and mapped Coulomb stress change onto these target faults. More importantly our calculations reveal that positive stress changes caused by the largest events of the 1976 Tangshan sequence make the Xiadian and part of Daxing fault, thus considered the most likely sites of the next strong earthquake in the study area. The accumulated static stress changes that reached a value of up to 0.4 bar onto these faults, were subsequently incorporated in earthquake probability estimates for the next 30 years.

  17. Neutronic-thermohydraulic oscillatory instability in modern PWRs due to high concentrations of boron in the water

    International Nuclear Information System (INIS)

    Novelli, A.

    1985-01-01

    Conspicuous amounts of boric acid are normally dissolved into the moderator of a modern PWR, especially in BOL operative conditions. If the concentration of such a neutronic poison attains certain limits, the nuclear temperature coefficient of the moderator, which is highly negative in the absence of boron, may turn about and reach positive values, due to the strong thermal expansion of the water. A dynamical model of a PWR system is presented, facilitating a quick stability analysis related to the co-ordination of boric acid solution in the water and control-rod insertion in the core. (author)

  18. Acute pulmonary edema due to stress cardiomyopathy in a patient with aortic stenosis: a case report

    OpenAIRE

    Bayer, Monika F

    2009-01-01

    Introduction Stress cardiomyopathy is a condition of chest pain, breathlessness, abnormal heart rhythms and sometimes congestive heart failure or shock precipitated by intense mental or physical stress. Case presentation A 64-year-old male with a known diagnosis of moderate-to-severe aortic stenosis and advised that valve replacement was not urgent, presented with acute pulmonary edema following extraordinary mental distress. The patient was misdiagnosed as having a "massive heart attack" and...

  19. Physical work load and psychological stress of daily activities as predictors of disability pension due to musculoskeletal disorders.

    Science.gov (United States)

    Ropponen, Annina; Svedberg, Pia; Koskenvuo, Markku; Silventoinen, Karri; Kaprio, Jaakko

    2014-06-01

    Physical work loading and psychological stress commonly co-occur in working life, hence potentially having an interrelationship that may affect work incapacity. This prospective cohort study aimed to investigate the effect of stability and change in physical work loading and stress on the risk of disability pension (DP) due to musculoskeletal diagnoses (MSD), while accounting for familial confounding in these associations. Data on 12,455 twins born before 1958 were surveyed of their physical work loading and psychological stress of daily activities in 1975 and 1981. The follow-up data was collected from pension registers until 2004. Cox proportional hazards regression models were used. During the follow up, 893 participants were granted DP due to MSD. Stable high (hazard ratio, HR, 2.21), but also increased physical work loading (HR 2.05) and high psychological stress (HR 2.22) were associated with increased risk for DP, and had significant interaction (p=0.032). The associations were confirmed when accounting for several confounding factors. Stable high but also increased physical work loading and psychological stress of daily activities between two timepoints with 6 years apart confirms their predictive role for an increased risk of DP. Both physical work loading and psychological stress seem to be independent from various confounding factors hence suggesting direct effect on risk for DP providing potential for occupational health care to early identification of persons at risk. © 2014 the Nordic Societies of Public Health.

  20. THE CONTAMINANT-ASSOCIATED STRESS RESPONSE AND ITS RELATIONSHIP TO PLASMA STRESS AND SEX STERIOD CONCENTRATIONS IN THE FLORIDA GAR, LEPISOSTEUS PLATYRHINCUS

    Science.gov (United States)

    Contaminants can alter the stress response. This study examined the stress response, defined by plasma cortisol concentration, and its relationship to plasma estradiol-17b and testosterone concentrations in adult gar collected from Lake Apopka, Orange Lake and Lake Woodruff NWR, ...

  1. Dramatic effect on Selenium concentration in blood serum due to the difference between the Hungarian and Indian dietary habits

    International Nuclear Information System (INIS)

    Szuecs, Z.; Lahiri, S.; Andrasi, D.; Kovacs, B.

    2012-01-01

    Complete text of publication follows. The importance of Selenium as trace element in animals, as well as in humans is well known. The deficiency of Selenium was observed in case of several heavy or fatal clinical events such as high infant mortality, premature, malformations and even prostate cancer. Hungary is in the top of their worldwide statistic with parallel of the low concentration of Selenium in soil as well as in food. The direct correlation can explain in Venezuela, where the prostate cancer is 'unknown disease'. The concentration of Selenium in India is higher than the worldwide level. Under the scientific bilateral cooperation 'Speciation dependent studies on physicochemical behavior of some elements in trace scale in natural and synthetic system' the Selenium was determined in human blood serum from the group of Hungarian and group of Indian patients. The samples were given in same time from each group. The main goal of the study was explain the effect of the traditional dietary habit for the level of Selenium. Therefore the samples were taken from the visiting scientist just arrived to the host institute as well as from the host scientists too. After 2 weeks stay the sampling was repeated, when the guest scientists eat the same food as the host scientists. The measurements were done in Thermo-2 ICP-MS from blood-serum separated by centrifuge. The results are summarized in Table 1. Dramatic effect was found for the level of Selenium in blood serum. As it was expected the Hungarian samples showed low concentration of Selenium in starting of the visit, as well as the high concentration was found in Indian sample, comparing to the Hungarian sample. After two weeks the Hungarian sample showed much higher concentration, however it was still less, than in Indian sample. Similar effect was found during the visit the Indian scientists in Hungary, however their Selenium concentration decreased not so spectacular due to the Selenium 'store' in body. The general

  2. Concentration of stresses and strains in a notched cyclinder of a viscoplastic material under harmonic loading

    Science.gov (United States)

    Zhuk, Ya A.; Senchenkov, I. K.

    1999-02-01

    Certain aspects of the correct definitions of stress and strain concentration factors for elastic-viscoplastic solids under cyclic loading are discussed. Problems concerning the harmonic kinematic excitation of cylindrical specimens with a lateral V-notch are examined. The behavior of the material of a cylinder is modeled using generalized flow theory. An approximate model based on the concept of complex moduli is used for comparison. Invariant characteristics such as stress and strain intensities and maximum principal stress and strain are chosen as constitutive quantities for concentration-factor definitions. The behavior of time-varying factors is investigated. Concentration factors calculated in terms of the amplitudes of the constitutive quantities are used as representative characteristics over the cycle of vibration. The dependences of the concentration factors on the loads are also studied. The accuracy of Nueber's and Birger's formulas is evaluated. The solution of the problem in the approximate formulation agrees with its solution in the exact formulation. The possibilities of the approximate model for estimating low-cycle fatigue are evaluated.

  3. Remote sensing of soybean stress as an indicator of chemical concentration of biosolid amended surface soils

    Science.gov (United States)

    Sridhar, B. B. Maruthi; Vincent, Robert K.; Roberts, Sheila J.; Czajkowski, Kevin

    2011-08-01

    The accumulation of heavy metals in the biosolid amended soils and the risk of their uptake into different plant parts is a topic of great concern. This study examines the accumulation of several heavy metals and nutrients in soybeans grown on biosolid applied soils and the use of remote sensing to monitor the metal uptake and plant stress. Field and greenhouse studies were conducted with soybeans grown on soils applied with biosolids at varying rates. The plant growth was monitored using Landsat TM imagery and handheld spectroradiometer in field and greenhouse studies, respectively. Soil and plant samples were collected and then analyzed for several elemental concentrations. The chemical concentrations in soils and roots increased significantly with increase in applied biosolid concentrations. Copper (Cu) and Molybdenum (Mo) accumulated significantly in the shoots of the metal-treated plants. Our spectral and Landsat TM image analysis revealed that the Normalized Difference Vegetative Index (NDVI) can be used to distinguish the metal stressed plants. The NDVI showed significant negative correlation with increase in soil Cu concentrations followed by other elements. This study suggests the use of remote sensing to monitor soybean stress patterns and thus indirectly assess soil chemical characteristics.

  4. Isopleths of surface concentration and surface exposure rate due to a radioactive cloud released from a stack

    International Nuclear Information System (INIS)

    Kobayashi, Hideo; Yabuta, Hajimu; Katagiri, Hiroshi; Obata, Kazuichi; Kokubu, Morinobu

    1982-03-01

    Various calculations are made to estimate the distributions of concentration and γ-exposure rate due to a radioactive cloud released from a point source to the atmosphere. In this report, the isopleths of concentration and γ-exposure rate which were calculated are given in graphs to enable rapid prediction of the influence of released radioactive material in the emergency situation. Recently there are facilities which are equipped with a system to display the calculation results on CRT; but such practice is rather rare. By placing the calculated isopleths of reduction scale 1/25000 or 1/50000 on the usual map, any facilities without the CRT system can readily estimate the influence of an accidental release. The graphs of isopleths are given with the release height (11 values of 0 to 200 m at about 20 m intervals) and the atmospheric stability (6 classes) as parameters. Calculations of γ-exposure rates were made using the computer code GAMPUL developed by T. Hayashi and T. Shiraishi. In the calculation of radioactive concentrations and γ-exposure rates, the vertical diffusion depths, σsub(z), exceeding 1000 m are taken to be 1000 m according to the Meteorological Guide for the Safety Analysis of Power Reactor (J.AEC). The comparison between with and without this limitation in σsub(z) is made in the case of downwind axial surface distributions. (author)

  5. Coupling analysis of the target temperature and thermal stress due to pulsed ion beam

    International Nuclear Information System (INIS)

    Yan Jie; Liu Meng; Lin Jufang; An Li; Long Xinggui

    2013-01-01

    Background: Target temperature has an important effect on the target life for the sealed neutron generator without cooling system. Purpose: To carry out the thermal-mechanical coupling analysis of the film-substrate target bombarded by the pulsed ion beam. Methods: The indirect coupling Finite Element Method (FEM) with a 2-dimensional time-space Gaussian axisymmetric power density as heat source was used to simulate the target temperature and thermal stress fields. Results: The effects of the target temperature and thermal stress fields under difference pulse widths and beam sizes were analyzed in terms of the FEM results. Conclusions: Combining with the temperature requirement and the thermal stress inducing film thermal mechanical destruction effect of the sealed neutron generator film-substrate targets, an optimized pulsed ion beam work status was proposed. (authors)

  6. Life time fatality risk assessment due to variation of indoor radon concentration in dwellings in western Haryana, India

    International Nuclear Information System (INIS)

    Kansal, Sandeep; Mehra, Rohit; Singh, N.P.

    2012-01-01

    Indoor radon measurements in 60 dwellings belonging to 12 villages of Sirsa, Fatehbad and Hisar districts of western Haryana, India, have been carried out, using LR-115 type II cellulose nitrate films in the bare mode. The annual average indoor radon value in the studied area varies from 76.00 to 115.46 Bq m −3 , which is well within the recommended action level 200–300 Bq m −3 (). The winter/summer ratio of indoor radon ranges from 0.78 to 2.99 with an average of 1.52. The values of annual average dose received by the residents and Life time fatality risk assessment due to variation of indoor radon concentration in dwellings of studied area suggests that there is no significance threat to the human beings due to the presence of natural radon in the dwellings. - Highlights: ► The radon concentration values in the dwellings are 2–3 times more than the world average of 40 Bq m −3 . ► These values are lower than the recommended action level of 200–300 Bq m −3 (). ► The annual effective dose is less than the recommended action level of 3–10 mSv per year (). ► The values of life time fatality risk determined for the studied area are within safe standards. ► There is no significant threat to the human beings due to the presence of natural radon in the dwellings.

  7. EDXS and XRD Analyses of Coleus with Different Concentration Selenium Supplements Under Lead Stress

    Directory of Open Access Journals (Sweden)

    QIN Hui-yuan

    2014-04-01

    Full Text Available In order to study the changes of the morphologies and element composition in Coleus hlumei Benth(Coleusroots and leaves under1.0 mmol·L-1 Pb2+ stress with selenium ( Setreatments, and to preliminarily investigate the relief mechanism of Se level on lead toxicity from the perspective of spectroscopy, Coleus was cultivated in nutrient solutions with different concentrations of Se. The results showed that the content of C, K and Ca elements in roots decreased, while 0, Mg, Al, Si, Fe and Pb elements increased under Pb stress with Se treatments. In addi-tion, the content of C, Mg, Al, Si, K, Ca and Fe elements in leaves decreased, while 0 and Cl elements increased. The element species and its contents in roots were changed obviously under Pb stress with Se treatments, and crystalline solid and crystal phase in roots were correspond-ingly changed.

  8. Honey bee (Apis mellifera) drones survive oxidative stress due to increased tolerance instead of avoidance or repair of oxidative damage.

    Science.gov (United States)

    Li-Byarlay, Hongmei; Huang, Ming Hua; Simone-Finstrom, Michael; Strand, Micheline K; Tarpy, David R; Rueppell, Olav

    2016-10-01

    Oxidative stress can lead to premature aging symptoms and cause acute mortality at higher doses in a range of organisms. Oxidative stress resistance and longevity are mechanistically and phenotypically linked; considerable variation in oxidative stress resistance exists among and within species and typically covaries with life expectancy. However, it is unclear whether stress-resistant, long-lived individuals avoid, repair, or tolerate molecular damage to survive longer than others. The honey bee (Apis mellifera L.) is an emerging model system that is well-suited to address this question. Furthermore, this species is the most economically important pollinator, whose health may be compromised by pesticide exposure, including oxidative stressors. Here, we develop a protocol for inducing oxidative stress in honey bee males (drones) via Paraquat injection. After injection, individuals from different colony sources were kept in common social conditions to monitor their survival compared to saline-injected controls. Oxidative stress was measured in susceptible and resistant individuals. Paraquat drastically reduced survival but individuals varied in their resistance to treatment within and among colony sources. Longer-lived individuals exhibited higher levels of lipid peroxidation than individuals dying early. In contrast, the level of protein carbonylation was not significantly different between the two groups. This first study of oxidative stress in male honey bees suggests that survival of an acute oxidative stressor is due to tolerance, not prevention or repair, of oxidative damage to lipids. It also demonstrates colony differences in oxidative stress resistance that might be useful for breeding stress-resistant honey bees. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Correlation of Stress Concentration Factors for T-Welded Connections – Finite Element Simulations and Fatigue Behavior

    Directory of Open Access Journals (Sweden)

    Gerardo Terán Méndez

    Full Text Available Abstract The stress concentration factors (SCFs in welded connections usually occur at zones with high stress levels. Stress concentrations reduce the fatigue behavior of welded connections in offshore structures and cracking can develop. By using the grinding technique, cracking can be eliminated. Stress concentration factors are defined as a ratio of maximum stress at the intersection to nominal stress on the brace. Defining the stress concentration factor is an important stage in the fatigue behavior of welded connections. Several approaches have evolved for designing structures with the classical S-N approach for estimating total life. This work correlates to the stress concentration factors of T-welded connections and the fatigue behavior. Stress concentration factors were computed with the finite element employing 3D T-welded connections with intact and grinding depth conditions. Then, T-welded connections were constructed with A36 plate steel and welded with E6013 electrodes to obtain the stress-life (S-N approach. The methodology from previous works was used to compute the SCF and fabricate the T-welded connections. The results indicated that the grinding process could restore the fatigue life of the T-welded connections for SCFs values in the range of 1.29. This value can be considered to be a low SCF value in T-welded connection. However, for higher SCF values, the fatigue life decreased, compromising and reducing the structural integrity of the T-welded connections.

  10. Estimating water stressed dwarf green bean pigment concentration through hyperspectral indices

    International Nuclear Information System (INIS)

    Koksal, E.S.; Ustrun, H.; Ozcan, H.; Gunturk, A.

    2010-01-01

    In this study, the relationship between leaf pigment concentration (analyzed in the laboratory) and four spectral indexes (measured in the field) was investigated. For this purpose, field experiments consisting of six different irrigation treatments were conducted with dwarf green beans during 2005 growing season. Based on spectral data, spectral indexes were plotted against pigment concentration. Results showed that under water stress, the chlorophyll and carotene contents of green bean leaves rose. According to linear regression analysis between spectral indexes and pigment contents, the Normalized Difference Pigment Chlorophyll Index (NPCI) and Normalized Difference Vegetation Index (NDVI) had the highest correlations with the chlorophyll (a, b and total), and carotene content of leaves. (author)

  11. Effect of Abiotic Stresses on the Nondestructive Estimation of Rice Leaf Nitrogen Concentration

    Directory of Open Access Journals (Sweden)

    Stephan M. Haefele

    2010-01-01

    Full Text Available Decision support tools for non-destructive estimation of rice crop nitrogen (N status (e.g., chlorophyll meter [SPAD] or leaf color chart [LCC] are an established technology for improved N management in irrigated systems, but their value in rainfed environments with frequent abiotic stresses remains untested. Therefore, we studied the effect of drought, salinity, phosphorus (P deficiency, and sulfur (S deficiency on leaf N estimates derived from SPAD and LCC measurements in a greenhouse experiment. Linear relations between chlorophyll concentration and leaf N concentration based on dry weight (Ndw between SPAD values adjusted for leaf thickness and Ndw and between LCC scores adjusted for leaf thickness and Ndw could be confirmed for all treatments and varieties used. Leaf spectral reflectance measurements did not show a stress-dependent change in the reflectance pattern, indicating that no specific element of the photosynthetic complex was affected by the stresses and at the stress level applied. We concluded that SPAD and LCC are potentially useful tools for improved N management in moderately unfavorable rice environments. However, calibration for the most common rice varieties in the target region is recommended to increase the precision of the leaf N estimates.

  12. Effect of Crack Tip Stress Concentration Factor on Fracture Resistance in Vacuum Environment

    Science.gov (United States)

    2015-01-20

    indicate: (1) in all alloys, the fracture resistance is highest for blunt-notches (smaller Kt), and is lowest for fatigue -sharpened precracked...paths are transgranular and the fracture mode is ductile void coalescence in all cases, irrespective of the stress concentration factor. 20-01-2015...because of corrosion and/or various loading conditions such as fatigue , fretting, abrasion, etc. Also, the geometry of the structure may cause an

  13. Hardening of particle/oil/water suspensions due to capillary bridges: Experimental yield stress and theoretical interpretation.

    Science.gov (United States)

    Danov, Krassimir D; Georgiev, Mihail T; Kralchevsky, Peter A; Radulova, Gergana M; Gurkov, Theodor D; Stoyanov, Simeon D; Pelan, Eddie G

    2018-01-01

    Suspensions of colloid particles possess the remarkable property to solidify upon the addition of minimal amount of a second liquid that preferentially wets the particles. The hardening is due to the formation of capillary bridges (pendular rings), which connect the particles. Here, we review works on the mechanical properties of such suspensions and related works on the capillary-bridge force, and present new rheological data for the weakly studied concentration range 30-55 vol% particles. The mechanical strength of the solidified capillary suspensions, characterized by the yield stress Y, is measured at the elastic limit for various volume fractions of the particles and the preferentially wetting liquid. A quantitative theoretical model is developed, which relates Y with the maximum of the capillary-bridge force, projected on the shear plane. A semi-empirical expression for the mean number of capillary bridges per particle is proposed. The model agrees very well with the experimental data and gives a quantitative description of the yield stress, which increases with the rise of interfacial tension and with the volume fractions of particles and capillary bridges, but decreases with the rise of particle radius and contact angle. The quantitative description of capillary force is based on the exact theory and numerical calculation of the capillary bridge profile at various bridge volumes and contact angles. An analytical formula for Y is also derived. The comparison of the theoretical and experimental strain at the elastic limit reveals that the fluidization of the capillary suspension takes place only in a deformation zone of thickness up to several hundred particle diameters, which is adjacent to the rheometer's mobile plate. The reported experimental results refer to water-continuous suspension with hydrophobic particles and oily capillary bridges. The comparison of data for bridges from soybean oil and hexadecane surprisingly indicate that the yield strength is

  14. Initialization shock in decadal hindcasts due to errors in wind stress over the tropical Pacific

    Science.gov (United States)

    Pohlmann, Holger; Kröger, Jürgen; Greatbatch, Richard J.; Müller, Wolfgang A.

    2017-10-01

    Low prediction skill in the tropical Pacific is a common problem in decadal prediction systems, especially for lead years 2-5 which, in many systems, is lower than in uninitialized experiments. On the other hand, the tropical Pacific is of almost worldwide climate relevance through its teleconnections with other tropical and extratropical regions and also of importance for global mean temperature. Understanding the causes of the reduced prediction skill is thus of major interest for decadal climate predictions. We look into the problem of reduced prediction skill by analyzing the Max Planck Institute Earth System Model (MPI-ESM) decadal hindcasts for the fifth phase of the Climate Model Intercomparison Project and performing a sensitivity experiment in which hindcasts are initialized from a model run forced only by surface wind stress. In both systems, sea surface temperature variability in the tropical Pacific is successfully initialized, but most skill is lost at lead years 2-5. Utilizing the sensitivity experiment enables us to pin down the reason for the reduced prediction skill in MPI-ESM to errors in wind stress used for the initialization. A spurious trend in the wind stress forcing displaces the equatorial thermocline in MPI-ESM unrealistically. When the climate model is then switched into its forecast mode, the recovery process triggers artificial El Niño and La Niña events at the surface. Our results demonstrate the importance of realistic wind stress products for the initialization of decadal predictions.

  15. Oxidative Stress in the Developing Rat Brain due to Production of Reactive Oxygen and Nitrogen Species

    Czech Academy of Sciences Publication Activity Database

    Wilhelm, Jiří; Vytášek, Richard; Uhlík, Jiří; Vajner, Luděk

    2016-01-01

    Roč. 2016, č. 2016 (2016), č. článku 5057610. ISSN 1942-0900 R&D Projects: GA ČR(CZ) GAP303/11/0298 Institutional support: RVO:67985823 Keywords : oxidative stress * developing rat brain * lipid peroxidation Subject RIV: ED - Physiology Impact factor: 4.593, year: 2016

  16. Genome-wide association of changes in swine feeding behaviour due to heat stress

    Science.gov (United States)

    Background: Heat stress has a negative impact on pork production, particularly during the grow-finish phase. As temperature increases, feeding behaviour changes in order for pigs to decrease heat production. The objective of this study was to identify genetic markers associated with changes in feedi...

  17. Behavior of surface residual stress in explosion hardened high manganese austenitic cast steel due to repeated impact loads

    International Nuclear Information System (INIS)

    Oda, Akira; Miyagawa, Hideaki

    1985-01-01

    Explosion hardened high manganese austenitic cast steel is being tried for rail crossing recently. From the previous studies, it became clear that high tensile residual stress was generated in the hardened surface layer by explosion and microcracks were observed. In this study, therefore, the behavior of surface residual stress in explosion hardened steel due to repeated impact loads was examined and compared with those of the original and shot peened steels. The results obtained are summarized as follows: (1) In the initial stage of the repetition of impact, high tensile surface residual stress in explosion hardened steel decreased rapidly with the repetition of impact, while those of the original and shot peened steels increased rapidly. This difference was attributed to the difference in depth of the work hardened layer in three testing materials. (2) Beyond 20 impacts the residual stress of three test specimens decreased gradually, and at more than 2000 impacts the compressive stress of about 500 MPa was produced regardless of the histories of working of testing materials. (3) The linear law in the second stage of residual stress fading was applicable to this case, and the range of the linear relationship was related to the depth of the work hardened layer of testing material. (4) From the changes in half-value breadth and peak intensity of diffraction X-ray, it was supposed that a peculiar microscopic strain exists in explosion hardened steel. (author)

  18. Activity concentration and population dose from natural occurring radionuclide (40K) due to consumption of fresh water fish

    International Nuclear Information System (INIS)

    Jha, M.K.; Patra, A.K.; Jaison, T.J.; Ravi, P.M.; Tripathi, R.M.

    2015-01-01

    The objective of this study was to measure the concentration of natural occurring radionuclide ( 40 K) in different fresh water fish collected from Moticher lake near Kakrapar, Gujarat. The three types of commonly available fresh water fish in Moticher lake are Notopterus sps, Ophiocephalus sps. and Tor sps. The 40 K activity (Bq/kg flesh wt.) was found to be in the range of 38-100 (Notopterus sps.), 33-123 (Ophiocephalus sps.) and 80-116 (Tor sps.) respectively. The ingestion dose (μSv/y) to the adult population around Kakrapar was estimated due to the consumption of fresh water fish and found to be in the range of 7.7-20.5 (Notopterus sps.), 6.8-25.0 (Ophiocephalus sps.) and 16.0-24.0 (Tor sps.) respectively. (author)

  19. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  20. Inhomogeneous Relaxation of a Molecular Layer on an Insulator due to Compressive Stress

    Science.gov (United States)

    Bocquet, F.; Nony, L.; Mannsfeld, S. C. B.; Oison, V.; Pawlak, R.; Porte, L.; Loppacher, Ch.

    2012-05-01

    We discuss the inhomogeneous stress relaxation of a monolayer of hexahydroxytriphenylene (HHTP) which adopts the rare line-on-line (LOL) coincidence on KCl(001) and forms moiré patterns. The fact that the hexagonal HHTP layer is uniaxially compressed along the LOL makes this system an ideal candidate to discuss the influence of inhomogeneous stress relaxation. Our work is a combination of noncontact atomic force microscopy experiments, density functional theory and potential energy calculations, and a thorough interpretation by means of the Frenkel-Kontorova model. We show that the assumption of a homogeneous molecular layer is not valid for this organic-inorganic heteroepitaxial system since the best calculated energy configuration correlates with the experimental data only if inhomogeneous relaxations of the layer are taken into account.

  1. Morphological Changes of Yeast Cells due to Oxidative Stress by Mercury and Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Su Hyoun; Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    The yeast Saccharomyces cerevisiae is one of the most important microorganisms employed in industry. Growth rate, mutation, and environmental conditions affect yeast size and shape distributions but, in general, the influence of spatial variations in large-scale bioreactors is not considered. Ionizing radiation induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm, and nucleus. Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. As a metal ion, it induces an oxidative stress or predisposes cells to an oxidative stress, with considerable damage to proteins, lipids and DNA. In this work, we investigated to effect of ionizing radiation (IR) and mercury chloride (II) on cell morphology.

  2. Service Life Of Main Piping Component Due To Low Thermal Stresses.Fatigue

    International Nuclear Information System (INIS)

    Miroshnik, R.; Jeager, A.; Ben Haim, H.

    1998-01-01

    The paper deals with estimating the service life of the power station Main piping component and describing the repair process for extending of its service life. After a long period of service, several circular fatigue cracks have been discovered at the bottom of the Main piping component chamber. Finite element analyses of transient thermal stresses, caused by power station startup, are carried out in the paper. The calculation results show good agreement between the theoretical locations of the maximum stresses and the actual locations of the cracks. There is a good agreement between theoretical evaluation and actual service life, as well. The possibility of machining out the cracks in order to prevent their growing is examined here. The machining enables us to extend the power station component's life service

  3. Storage of spent fuels: implementation of a research program on the risk of waste container rupture due to stress corrosion induced by fission products

    International Nuclear Information System (INIS)

    Parise, M.; Walle, E.; Foct, J.

    2001-01-01

    The following topics were dealt with: research programm on stress corrosion of spent fuel casks materials due to fission products, such as iodine, chemical interactions with zirconium, chemical aspects of stress corrosion, rupture risk assessment

  4. Ferroelectric behavior of a lead titanate nanosphere due to depolarization fields and mechanical stresses

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Landeta, J.; Lascano, I.

    2017-07-01

    A theorical model has been developed based on the theory of Ginzburg-Landau-Devonshire to study and predict the effects the decreasing of size particle in a nanosphere of PbTiO3 subjected to the action of depolarization fields and mechanical stress. It was considered that the nanosphere is surrounded by a layer of space charges on its surface, and containing 180° domains generated by minimizing free energy of depolarization. Energy density of depolarization, wall domain and electro-elastic energy have been incorporated into the free energy of the theory Ginzburg-Landau-Devonshire. Free energy minimization was performed to determine the spontaneous polarization and transition temperature system. These results show that the transition temperature for nanosphere is substantially smaller than the corresponding bulk material. Also, it has been obtained that the stability of the ferroelectric phase of nanosphere is favored for configurations with a large number of 180° domains, with the decreasing of thickness space charge layer, and the application of tensile stress and decreases with compressive stress. (Author)

  5. Surplus dietary tryptophan reduces plasma cortisol and noradrenaline concentrations and enhances recovery after social stress in pigs

    NARCIS (Netherlands)

    Koopmans, S.J.; Ruis, M.A.W.; Dekker, R.A.; Diepen, van J.T.M.; Korte, S.M.; Mroz, Z.

    2005-01-01

    Social stress occurs in intensive pig farming due to aggressive behavior. This stress may be reduced at elevated dietary levels of tryptophan (TRP). In this study, we compared the effects of high (13.2%) vs. normal (3.4%) dietary TRP to large neutral amino acid (LNAA) ratios on behavior and stress

  6. Antioxidant-enzyme reaction to the oxidative stress due to alpha-cypermethrin, chlorpyriphos, and pirimicarb in tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Chahid, Karim; Laglaoui, Amin; Zantar, Said; Ennabili, Abdeslam

    2015-11-01

    Tomato (Lycopersicon esculentum Mill.) becomes one of the world's foremost vegetables, and its world production and consumption have increased fairly quickly. The capacity to induce oxidative stress in tomato plant, exposed to three xenobiotics such as alpha-cypermethrin, chlorpyriphos, and pirimicarb, was investigated by the evaluation of lipid peroxidation by measuring malondialdehyde (MDA) rate; also, we studied the response of tomato to this stress by assessing the response of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione-s-transferase (GST), and glutathione reductase (GR). The effect of the insecticides was observed using four concentrations (25, 50, 75, and 100%) for germinating seeds and only the recommended concentration in agriculture (100%) for growing plants. Our results show an important accumulation of MDA, demonstrating the increase of lipid peroxidation in consequence of the excessive reactive oxygen species (ROS) production due to insecticide treatment. In response to this oxidative stress in tomato seedlings and plants, the activities of antioxidant-enzyme system were generally enhanced. The electrophoretic analysis showed also the apparition of new isoenzymes as the case for CAT and POD.

  7. Worsening of Heat Stress Due To Global Warming in South Korea Based on Multi-RCM Ensemble Projections

    Science.gov (United States)

    Im, Eun-Soon; Choi, Yeon-Woo; Ahn, Joong-Bae

    2017-11-01

    This study assesses the future changes in summer (June-July-August; JJA) heat stress over South Korea under global warming. To better resolve the region-specific changes in terms of geographical patterns and severity of heat stress in the Korean peninsula, four regional climate models (RCMs) are used for dynamical downscaling of Hadley Centre Global Environmental Model version 2—Atmosphere and Ocean global projections forced by two Representative Concentration Pathway (RCP4.5 and RCP8.5) scenarios. Dynamically downscaled simulations (horizontal resolution of 12.5 km and output interval of 3 h) facilitate in-depth analysis of diurnal variation and extremes over South Korea, as well as focusing on the particular location, Daegu, that is characterized by high vulnerability to rising temperature. Both maximum temperature and heat stress indices such as wet bulb globe temperature and apparent temperature, which include the effect of humidity, are examined in order to comprehensively interpret the behaviors of heat stress in response to anthropogenic climate change. Ensemble projections reveal robust patterns of temperature and resultant humidity increases that are roughly constrained by the approximate 7%/K increase in the moisture holding capacity. The changes in temperature and humidity are directly transmitted to the heat stress indices, showing a significant increase. The heat stress is exacerbated in a differentiated way, with more intensification in diurnal variation at nighttime and in regional variation at low-elevation basins. Both RCP4.5 and RCP8.5 scenarios project the statistical likelihood of a notable increase of extreme heat stress indices, much stronger and more extended heat waves, and the emergence of a long period of consecutive tropical nights.

  8. Exploring the uncertainty in attributing sediment contributions in fingerprinting studies due to uncertainty in determining element concentrations in source areas.

    Science.gov (United States)

    Gomez, Jose Alfonso; Owens, Phillip N.; Koiter, Alex J.; Lobb, David

    2016-04-01

    One of the major sources of uncertainty in attributing sediment sources in fingerprinting studies is the uncertainty in determining the concentrations of the elements used in the mixing model due to the variability of the concentrations of these elements in the source materials (e.g., Kraushaar et al., 2015). The uncertainty in determining the "true" concentration of a given element in each one of the source areas depends on several factors, among them the spatial variability of that element, the sampling procedure and sampling density. Researchers have limited control over these factors, and usually sampling density tends to be sparse, limited by time and the resources available. Monte Carlo analysis has been used regularly in fingerprinting studies to explore the probable solutions within the measured variability of the elements in the source areas, providing an appraisal of the probability of the different solutions (e.g., Collins et al., 2012). This problem can be considered analogous to the propagation of uncertainty in hydrologic models due to uncertainty in the determination of the values of the model parameters, and there are many examples of Monte Carlo analysis of this uncertainty (e.g., Freeze, 1980; Gómez et al., 2001). Some of these model analyses rely on the simulation of "virtual" situations that were calibrated from parameter values found in the literature, with the purpose of providing insight about the response of the model to different configurations of input parameters. This approach - evaluating the answer for a "virtual" problem whose solution could be known in advance - might be useful in evaluating the propagation of uncertainty in mixing models in sediment fingerprinting studies. In this communication, we present the preliminary results of an on-going study evaluating the effect of variability of element concentrations in source materials, sampling density, and the number of elements included in the mixing models. For this study a virtual

  9. Physiological effects of autotoxicity due to DHAP stress on Picea schrenkiana regeneration.

    Directory of Open Access Journals (Sweden)

    Li Yang

    Full Text Available Picea Schrenkiana as one of the most important zonal vegetation was an endemic species in Middle Asia. Natural regeneration of P. Schrenkiana is a long existing problem troubling scientists. The autotoxicity of 3,4-dihydroxy-acetophenone (DHAP was found to be a causative factor causing the failure of P. Schrenkiana natural regeneration. The effects of concentrations of DHAP treatment on the viability of root cell, activities of antioxidant enzymes and levels of P. Schrenkiana phytohormones were performed to disclose the physiological mechanism of DHAP autotoxicity. It was observed that high concentration of DHAP could inhibit the seed germination and seedling growth, but had a hormesis at low concentrations. Analyses showed that the root cells significantly lost their viability treated with high DHAP. The enzymes activities of seedlings were significantly stimulated by the treatment of 0.5 mM DHAP to give a transient increase and then decrease as DHAP concentration increased to 1.0 mM except for GR (glutathione reductase in which DHAP treatment had little effect on its activity. Comparing with the control, an increase in the levels of phytohormones ZT (zeatin, GA3 (gibberellic acid and IAA (indole acetic acid was induced by the treatment of DHAP at low concentrations (0.1-0.25 mM, but the significant deficiency was found treated by high concentrations (0.5-1.0 mM. In addition, the ABA (abscisic acid level increased in all experimental observations. These results suggested that DHAP significantly affected indices of growth and physiology, and provided some new information about different effect in P. Schrenkiana treated with DHAP.

  10. Simulation of inter- and transgranular crack propagation in polycrystalline aggregates due to stress corrosion cracking

    International Nuclear Information System (INIS)

    Musienko, Andrey; Cailletaud, Georges

    2009-01-01

    The motivation of the study is the development of a coupled approach able to account for the interaction between environment and plasticity in a polycrystalline material. The paper recalls first the constitutive equations used to describe the behavior of the grain core and of the grain boundary (GB). The procedure that is applied to generate synthetic polycrystalline aggregates with an explicit representation of the grain boundary area by 2D or 3D finite elements is then described. The approach is applied to the modeling of iodine-assisted stress corrosion cracking (IASCC) in Zircaloy tubes used in nuclear power plants.

  11. Advanced LMFBR fuel cladding susceptability to stress corrosion due to reprocessing impurities

    International Nuclear Information System (INIS)

    Henslee, S.P.

    1987-03-01

    The potential degradation of LMFBR fuel cladding alloys by chlorides, when used in metallic fuel systems, was evaluated. The alloys tested were D-9 and HT-9 stainless steels, austenitic and ferritic alloys respectively. These two alloys were tested in parallel with and their performance compared to the austenitic stainless steel Type 316. All alloys were tested for 7400 hours in a stress rupture environment with chloride exposure at either 550/degree/C 650/degree/C. None of the alloys tested were found to exhibit any degradation in time-to-rupture by the presence of chlorides under the conditions imposed during testing. 8 refs., 4 figs., 2 tabs

  12. Reliability assessment of stress concentration performance state for a perforated composite plate under traction

    Directory of Open Access Journals (Sweden)

    Jabbouri A.

    2012-07-01

    Full Text Available Considering a perforated sandwich plate made from two elastic homogenous and isotropic layers, and having a square hole, reliability assessment of stress concentration limit state for which the stress should not exceed a given threshold is performed in this work. Assuming that the plate dimensions and the applied loading are deterministic, focus is done on the square hole centre position and edge length considered to be random variables. The means and the standard deviations of these variables are assumed to be known, but no information is so far available about their densities of probabilities. To assess reliability of the performance state, reliability analysis known methods are applied to a response surface representation of the stress concentration factor of the perforated plate which is obtained through quadratic polynomial regression of finite element results. A parametric study is performed regarding the influence of the distributions of probabilities chosen to model the hole dimensions uncertainties. It is shown that the probability of failure depends largely on the selected densities of probabilities.

  13. Serum thiamine concentration and oxidative stress as predictors of mortality in patients with septic shock.

    Science.gov (United States)

    Costa, Nara Aline; Gut, Ana Lúcia; de Souza Dorna, Mariana; Pimentel, José Alexandre Coelho; Cozzolino, Silvia Maria Franciscato; Azevedo, Paula Schmidt; Fernandes, Ana Angélica Henrique; Zornoff, Leonardo Antonio Mamede; de Paiva, Sergio Alberto Rupp; Minicucci, Marcos Ferreira

    2014-04-01

    The purpose of the study is to determine the influence of serum thiamine, glutathione peroxidase (GPx) activity, and serum protein carbonyl concentrations in hospital mortality in patients with septic shock. This prospective study included all patients with septic shock on admission or during intensive care unit (ICU) stay, older than 18 years, admitted to 1 of the 3 ICUs of the Botucatu Medical School, from January to August 2012. Demographic information, clinical evaluation, and blood sample were taken within the first 72 hours of the patient's admission or within 72 hours after septic shock diagnosis for serum thiamine, GPx activity, and protein carbonyl determination. One hundred eight consecutive patients were evaluated. The mean age was 57.5 ± 16.0 years, 63% were male, 54.6% died in the ICU, and 71.3% had thiamine deficiency. Thiamine was not associated with oxidative stress. Neither vitamin B1 levels nor the GPx activity was associated with outcomes in these patients. However, protein carbonyl concentration was associated with increased mortality. In patients with septic shock, oxidative stress was associated with mortality. On the other hand, thiamine was not associated with oxidative stress or mortality in these patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Glutamate/glutamine concentrations in the dorsal anterior cingulate vary with Post-Traumatic Stress Disorder symptoms.

    Science.gov (United States)

    Harnett, Nathaniel G; Wood, Kimberly H; Ference, Edward W; Reid, Meredith A; Lahti, Adrienne C; Knight, Amy J; Knight, David C

    2017-08-01

    Trauma and stress-related disorders (e.g., Acute Stress Disorder; ASD and Post-Traumatic Stress Disorder; PTSD) that develop following a traumatic event are characterized by cognitive-affective dysfunction. The cognitive and affective functions disrupted by stress disorder are mediated, in part, by glutamatergic neural systems. However, it remains unclear whether neural glutamate concentrations, measured acutely following trauma, vary with ASD symptoms and/or future PTSD symptom expression. Therefore, the current study utilized proton magnetic resonance spectroscopy ( 1 H-MRS) to investigate glutamate/glutamine (Glx) concentrations within the dorsal anterior cingulate cortex (ACC) of recently (i.e., within one month) traumatized individuals and non-traumatized controls. Although Glx concentrations within dorsal ACC did not differ between recently traumatized and non-traumatized control groups, a positive linear relationship was observed between Glx concentrations and current stress disorder symptoms in traumatized individuals. Further, Glx concentrations showed a positive linear relationship with future stress disorder symptoms (i.e., assessed 3 months post-trauma). The present results suggest glutamate concentrations may play a role in both acute and future post-traumatic stress symptoms following a traumatic experience. The current results expand our understanding of the neurobiology of stress disorder and suggest glutamate within the dorsal ACC plays an important role in cognitive-affective dysfunction following a traumatic experience. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Laser-induced cracks in ice due to temperature gradient and thermal stress

    Science.gov (United States)

    Yang, Song; Yang, Ying-Ying; Zhang, Jing-Yuan; Zhang, Zhi-Yan; Zhang, Ling; Lin, Xue-Chun

    2018-06-01

    This work presents the experimental and theoretical investigations on the mechanism of laser-induce cracks in ice. The laser-induced thermal gradient would generate significant thermal stress and lead to the cracking without thermal melting in the ice. The crack density induced by a pulsed laser in the ice critically depends on the laser scanning speed and the size of the laser spot on the surface, which determines the laser power density on the surface. A maximum of 16 cracks within an area of 17 cm × 10 cm can be generated when the laser scanning speed is at 10 mm/s and the focal point of the laser is right on the surface of the ice with a laser intensity of ∼4.6 × 107 W/cm2. By comparing the infrared images of the ice generated at various experimental conditions, it was found that a larger temperature gradient would result in more laser-induced cracks, while there is no visible melting of the ice by the laser beam. The data confirm that the laser-induced thermal stress is the main cause of the cracks created in the ice.

  16. Intragenic origins due to short G1 phases underlie oncogene-induced DNA replication stress.

    Science.gov (United States)

    Macheret, Morgane; Halazonetis, Thanos D

    2018-03-01

    Oncogene-induced DNA replication stress contributes critically to the genomic instability that is present in cancer. However, elucidating how oncogenes deregulate DNA replication has been impeded by difficulty in mapping replication initiation sites on the human genome. Here, using a sensitive assay to monitor nascent DNA synthesis in early S phase, we identified thousands of replication initiation sites in cells before and after induction of the oncogenes CCNE1 and MYC. Remarkably, both oncogenes induced firing of a novel set of DNA replication origins that mapped within highly transcribed genes. These ectopic origins were normally suppressed by transcription during G1, but precocious entry into S phase, before all genic regions had been transcribed, allowed firing of origins within genes in cells with activated oncogenes. Forks from oncogene-induced origins were prone to collapse, as a result of conflicts between replication and transcription, and were associated with DNA double-stranded break formation and chromosomal rearrangement breakpoints both in our experimental system and in a large cohort of human cancers. Thus, firing of intragenic origins caused by premature S phase entry represents a mechanism of oncogene-induced DNA replication stress that is relevant for genomic instability in human cancer.

  17. Thermoelastic stress due to an instantaneous finite line heat source in an infinite medium

    International Nuclear Information System (INIS)

    Claesson, J.; Hellstroem, G.

    1995-09-01

    The problem originates from studies of nuclear waste repositories in rock. The problem is by superposition reduced to the case of a single, infinite, antisymmetric, instantaneous line heat source. The dimensionless problem turns out to depend on the dimensionless radial and axial coordinates only, although the original time-dependent problem contains several parameters. An exact analytical solution is derived. The solution is surprisingly handy, considering the complexity of the original problem. The stress and strain field are readily obtained from derivatives of the displacement components. These fields are studied and presented in detail. Asymptotic behaviour, field of principal stresses, regions of compression and tension, and largest values of compression and tension of the components are given as exact formulas. The solution may be used to test numerical models for coupled thermoelastic processes. It may also be used in more detailed numerical simulations of the process near the heat sources as boundary conditions to account for the three-dimensional global process. 7 refs

  18. Cholesterol-producing transgenic Caenorhabditis elegans lives longer due to newly acquired enhanced stress resistance

    International Nuclear Information System (INIS)

    Lee, Eun-Young; Shim, Yhong-Hee; Chitwood, David J.; Hwang, Soon Baek; Lee, Junho; Paik, Young-Ki

    2005-01-01

    Because Caenorhabditis elegans lacks several components of the de novo sterol biosynthetic pathway, it requires sterol as an essential nutrient. Supplemented cholesterol undergoes extensive enzymatic modification in C. elegans to form other sterols of unknown function. 7-Dehydrocholesterol reductase (DHCR) catalyzes the reduction of the Δ 7 double bond of sterols and is suspected to be defective in C. elegans, in which the major endogenous sterol is 7-dehydrocholesterol (7DHC). We microinjected a human DHCR expression vector into C. elegans, which was then incorporated into chromosome by γ-radiation. This transgenic C. elegans was named cholegans, i.e., cholesterol-producing C. elegans, because it was able to convert 7DHC into cholesterol. We investigated the effects of changes in sterol composition on longevity and stress resistance by examining brood size, mean life span, UV resistance, and thermotolerance. Cholegans contained 80% more cholesterol than the wild-type control. The brood size of cholegans was reduced by 40% compared to the wild-type control, although the growth rate was not significantly changed. The mean life span of cholegans was increased up to 131% in sterol-deficient medium as compared to wild-type. The biochemical basis for life span extension of cholegans appears to partly result from its acquired resistance against both UV irradiation and thermal stress

  19. Life prediction of steam generator tubing due to stress corrosion crack using Monte Carlo Simulation

    International Nuclear Information System (INIS)

    Hu Jun; Liu Fei; Cheng Guangxu; Zhang Zaoxiao

    2011-01-01

    Highlights: → A life prediction model for SG tubing was proposed. → The initial crack length for SCC was determined. → Two failure modes called rupture mode and leak mode were considered. → A probabilistic life prediction code based on Monte Carlo method was developed. - Abstract: The failure of steam generator tubing is one of the main accidents that seriously affects the availability and safety of a nuclear power plant. In order to estimate the probability of the failure, a probabilistic model was established to predict the whole life-span and residual life of steam generator (SG) tubing. The failure investigated was stress corrosion cracking (SCC) after the generation of one through-wall axial crack. Two failure modes called rupture mode and leak mode based on probabilistic fracture mechanics were considered in this proposed model. It took into account the variance in tube geometry and material properties, and the variance in residual stresses and operating conditions, all of which govern the propagations of cracks. The proposed model was numerically calculated by using Monte Carlo Simulation (MCS). The plugging criteria were first verified and then the whole life-span and residual life of the SG tubing were obtained. Finally, important sensitivity analysis was also carried out to identify the most important parameters affecting the life of SG tubing. The results will be useful in developing optimum strategies for life-cycle management of the feedwater system in nuclear power plants.

  20. Stress Concentration Factor of Expanded Aluminum Tubes Using Finite Element Modeling

    Directory of Open Access Journals (Sweden)

    L Mhamdi

    2013-06-01

    Full Text Available This paper discusses the development of semi-empirical relations for the maximum stress concentration factor (SCF around circular holes embedded in aluminum tubes under various expansion ratios and mandrel angles. Finite element models were developed to study the expansion of a typical aluminum tube with embedded holes of various sizes. An elastic perfectly-plastic material behaviour was used to describe the structural response of the tubes under expansion. Various hole-diameter-to-tubewall- thickness ratios, tube expansion ratios, and mandrel angles were considered to determine the stress state around the hole at zero and 90 degree locations from which the maximum SCF was determined. Semi-empirical relations for the maximum SCF using the Lagrange interpolation formulation were developed. The developed relations were found to predict the SCFs accurately.

  1. Numerical Investigation on Stress Concentration of Tension Steel Bars with One or Two Corrosion Pits

    Directory of Open Access Journals (Sweden)

    Jian Hou

    2015-01-01

    Full Text Available Pitting corrosion has been observed in steel bars of existing reinforced concrete (RC structures in different erosion environments and has been identified as a potential origin for fatigue crack nucleation. In the present study, under uniaxial tension loading, stress distribution in the steel bars with one or two semiellipsoidal corrosion pits has systematically been investigated by conducting a series of three-dimensional semiellipsoidal pitted models. Based on the finite element analyses, it is shown that stress concentration factor (SCF increases linearly with increasing pit aspect ratio (a/b and increases nonlinearly with increasing pit relative depth (a/R for single corrosion pit problem. For double corrosion pits problem, the SCF decreases nonlinearly with increasing angle of two transverse pits (θ. The interaction of two longitudinal pits can be ignored in the calculation of SCF even if the distance of two pits (d is very small.

  2. An fMRI study on variation of visuospatial cognitive performance of young male due to highly concentrated oxygen administration

    Science.gov (United States)

    Chung, Soon Cheol; Kim, Ik Hyeon; Tack, Gye Rae; Sohn, Jin Hun

    2004-04-01

    This study investigated the effects of 30% oxygen administration on the visuospatial cognitive performance using fMRI. Eight college students (right-handed, average age 23.5) were selected as subjects for this study. Oxygen supply equipment which gives 21% and 30% oxygen at a constant rate of 8L/min was developed for this study. To measure the performance of visuospatial cognition, two questionnaires with similar difficulty containing 20 questions each were also developed. Experiment was designed as two runs: run for visuospatial cognition test with normal air (21% of oxygen) and run for visuospatial cognition test with highly concentrated air (30% of oxygen). Run consists of 4 blocks and each block has 8 control problems and 5 visuospatial problems. Functional brain images were taken from 3T MRI using single-shot EPI method. Activities of neural network due to performing visuospatial cognition test were identified using subtraction procedure, and activation areas while performing visuospatial cognition test were extracted using double subtraction procedure. Activities were observed at occipital lobe, parietal lobe, and frontal lobe when performing visuospatial cognition test following both 21% and 30% oxygen administration. But in case of only 30% oxygen administration there were more activities at left precuneus, left cuneus, right postcentral gyrus, bilateral middle frontal gyri, right inferior frontal gyrus, left superior frontal gyrus, bilateral uvula, bilateral pyramis, and nodule compared with 21% oxygen administration. From results of visuospatial cognition test, accuracy rate increased in case of 30% oxygen administration. Thus it could be concluded that highly concentrated oxygen administration has positive effects on the visuospatial cognitive performance.

  3. Fractures in high-strength bolts due to hydrogen induced stress corrosion. Causes and corrective actions

    International Nuclear Information System (INIS)

    Hoche, Holger; Oechsner, Matthias

    2017-01-01

    Delayed brittle fractures of high-strength bolts of the strength class 10.9 are presented, taking the example of three damage cases. The respective damage mechanisms could be attributed to hydrogen induced stress corrosion which was caused, in turn, by hydrogen absorption during operation. The examples were chosen with a particular focus on the material condition's susceptibility which explains the cause for the occurrence of the damage mechanism. However, in only one of the three cases the susceptibility was evident and could be explained by violations of normative specifications and an unfavorable material choice. Whereas in the two other examples, only slight or no deviations from the standards and/or regulations could be found. The influencing parameters that caused the damage, those that further promoted the damage, as well as possible corrective actions are discussed taking into account the three exemplary damage cases.

  4. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    DEFF Research Database (Denmark)

    Chen, Jun; Shen, Jing; Solem, Christian

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed...... riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C....... These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller...

  5. Rennet-induced gelation of concentrated milk in the presence of sodium caseinate: differences between milk concentration using ultrafiltration and osmotic stressing.

    Science.gov (United States)

    Krishnankutty Nair, P; Corredig, M

    2015-01-01

    Concentrating milk is a common unit operation in the dairy industry. With the reduction of water, the particles interact more frequently with each other and the functionality of the casein micelles may depend on the interactions occurring during concentration. The objective of this research was to investigate the effect of concentration on the renneting properties of the casein micelles by comparing 2 concentration methods: ultrafiltration and osmotic stressing. Both methods selectively concentrate the protein fraction of milk, while the composition of the soluble phase is unaltered. To evaluate possible differences in the rearrangements of the casein micelles during concentration, renneting properties were evaluated with or without the addition of soluble caseins, added either before or after concentration. The results indicate that casein micelles undergo rearrangements during concentration and that shear during membrane filtration may play a role in affecting the final properties of the milk. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. Estimation of inelastic behavior for a tapered nozzle in vessel due to thermal transient load using stress redistribution locus method

    International Nuclear Information System (INIS)

    Kobayashi, Ken-ichi; Yamada, Jun-ichi

    2010-01-01

    Simplified inelastic design procedures for elevated temperature components have been required to reduce simulation cost and to shorten a period of time for developing new projects. Stress redistribution locus (SRL) method has been proposed to provide a reasonable estimate employing both the elastic FEM analysis and a unique hyperbolic curve: ε tilde={1/σ tilde + (κ - 1)σ tilde}/κ, where ε tilde and σ tilde show dimensionless strain and stress normalized by corresponding elastic ones, respectively. This method is based on a fact that stress distribution in well deformed or high temperature components would change with deformation or time, and that the relation between the dimensionless stress and strain traces a kind of the elastic follow-up locus in spite of the constitutive equation of material and loading modes. In this paper, FEM analyses incorporating plasticity and creep in were performed for a tapered nozzle in reactor vessel under some thermal transient loads through the nozzle thickness. The normalized stress and strain was compared with the proposed SRL curve. Calculation results revealed that a critical point in the tapered nozzle due to the thermal transient load depended on a descending rate of temperature from the higher temperature in the operation cycle. Since the inelastic behavior in the nozzle resulted in a restricted area, the relationship between the normalized stress and strain was depicted inside the proposed SRL curve: Coefficient κ of the SRL in analyses is greater than the proposed one, and the present criterion guarantees robust structures for complicated components involving inelastic deformation. (author)

  7. Effects of potential and concentration of bicarbonate solution on stress corrosion cracking of annealed carbon steel

    International Nuclear Information System (INIS)

    Haruna, Takumi; Zhu, Liehong; Murakami, Makoto; Shibata, Toshio

    2000-01-01

    Effects of potential and concentration of bicarbonate on stress corrosion cracking (SCC) of annealed SM 400 B carbon steel has been investigated in bicarbonate solutions at 343 K. The surface of annealed specimen had decarburized layer of about 0. 5 mm thickness. A potentiostatic slow strain rate testing apparatus equipped with a charge coupled device camera system was employed to evaluate SCC susceptibility from the viewpoint of the crack behavior. In a constant bicarbonate concentration of 1 M, cracks were observed in the potential range from -800 to 600 mV Ag/ A gCl . and especially, the initiation and the propagation of the cracks were accelerated at -600 mV. At a constant potential of -600 mV, cracks were observed in the concentration range from 0.001 to 1 M, and the initiation and the propagation of the cracks were suppressed as the concentration decreased. Polarization curves for the decarburized surface were measured with two different scan rates. High SCC susceptibility may be expected in the potential range where the difference between the two current densities is large. It was found in this system that the potential with the maximum difference in the current density was -600 mV for 1 M bicarbonate solution, and the potential increased with a decrease in the concentration of bicarbonate. This means that an applied potential of -600 mV provides the highest SCC susceptibility for 1 M bicarbonate solution, and that the SCC susceptibility decreases as the concentration decreases. These findings support the dependence of the actual SCC behavior on the potential and the concentration of bicarbonate. (author)

  8. On a class of problems on interaction of stress concentrators of different types with an elastic semi-infinite plate

    Science.gov (United States)

    Mkhitaryan, S. M.

    2018-04-01

    A class of mixed boundary-value problems of mathematical theory of elasticity dealing with interaction between stress concentrators of different types (such as cracks, absolutely rigid thin inclusions, punches, and stringers) and an elastic semi-infinite plate is considered. The method of Mellin integral transformation is used to reduce solving these problems to solving singular integral equations (SIE). After the governing SIE are solved, the following characteristics of the problem are determined: tangential contact stresses under stringers, dislocation density on the crack edges, breaking stresses outside the cracks on their line of location, the stress intensity factor (SIF), crack openings, jumps of contact stresses on the edges of inclusions.

  9. Mechanical and thermal stresses in a functionally graded rotating disk with variable thickness due to radially symmetry loads

    International Nuclear Information System (INIS)

    Bayat, Mehdi; Saleem, M.; Sahari, B.B.; Hamouda, A.M.S.; Mahdi, E.

    2009-01-01

    Rotating disks have many applications in the aerospace industry such as gas turbines and gears. These disks normally work under thermo mechanical loads. Minimizing the weight of such components can help reduce the overall payload in aerospace industry. For this purpose, a rotating functionally graded (FG) disk with variable thickness under a steady temperature field is considered in this paper. Thermo elastic solutions and the weight of the disk are related to the material grading index and the geometry of the disk. It is found that a disk with parabolic or hyperbolic convergent thickness profile has smaller stresses and displacements compared to a uniform thickness disk. Maximum radial stress due to centrifugal load in the solid disk with parabolic thickness profile may not be at the center unlike uniform thickness disk. Functionally graded disk with variable thickness has smaller stresses due to thermal load compared to those with uniform thickness. It is seen that for a given value of grading index, the FG disk having concave thickness profile is the lightest in weight whereas the FG disk with uniform thickness profile is the heaviest. Also for any given thickness profile, the weight of the FG disk lies in between the weights of the all-metal and the all-ceramic disks.

  10. Quantification of nanoparticle release from polymer nanocomposite coatings due to environmental stressing.

    Science.gov (United States)

    Kim, Yeon Seok; Davis, Rick; Uddin, Nasir; Nyden, Marc; Rabb, Savelas A

    2016-01-01

    Certain engineered nanoparticles (ENP) reduce the flammability of components used in soft furnishings (mattresses and upholstered furniture). However, because of the ENP's small size and ability to interact with biological molecules, these fire retardant ENPs may pose a health and environmental risks, if they are released sometime during the life cycle of the soft furnishing. Quantifying the released amount of these ENPs under normal end-use circumstances provides a basis for assessing their potential health and environmental impact. In this article, we report on efforts to identify suitable methodologies for quantifying the release of carbon nanofibers, carbon nanotubes, and sodium montmorillonites from coatings applied to the surfaces of barrier fabric and polyurethane foam. The ENPs released in simulated chewing and mechanical stressing experiments were collected in aqueous solution and quantified using Ultraviolet-Visible and inductively coupled plasma-optical emission spectroscopy. The microstructures of the released ENPs were characterized using scanning electron microscopy. The reported methodology and results provide important milestones to estimate the impact and toxicity of the ENP release during the life cycle of the nanocomposites. To our knowledge, this is the first study of ENP release from the soft furnishing coating, something that can be important application area for fire safety.

  11. Intrapartum sacral stress fracture due to pregnancy-related osteoporosis: a case report.

    Science.gov (United States)

    Oztürk, Gülcan; Külcü, Duygu Geler; Aydoğ, Ece

    2013-01-01

    Low back pain (LBP) and hip pain frequently occur during pregnancy and postpartum period. Although pelvic and mechanic lesions of the soft tissues are most responsible for the etiology, sacral fracture is also one of the rare causes. A 32-year-old primigravid patient presented with LBP and right hip pain which started 3 days after vaginal delivery. Although direct radiographic examination was normal, magnetic resonance imaging of the sacrum revealed sacral stress fracture. Lumbar spine and femoral bone mineral density showed osteoporosis as a risk factor. There were no other risk factors such as trauma, excessive weight gain, and strenuous physical activity. It is considered that the patient had sacral fatigue and insufficiency fracture in intrapartum period. The patient's symptoms subsided in 3 months after physical therapy and rest. In conclusion, sacral fractures during pregnancy and postpartum period, especially resulting from childbirth, are very rare. To date, there are two cases in the literature. In cases who even do not have risk factors related to vaginal delivery such as high birth weight infant and the use of forceps, exc., sacral fracture should be considered in the differential diagnosis of LBP and hip pain started soon after child birth. Pregnancy-related osteoporosis may lead to fracture during vaginal delivery.

  12. [STRESS DUE TO THE WORK-LIFE CONFLICT: ADVICES FROM APPLIED RESEARCH FOR COPING IT].

    Science.gov (United States)

    Poerio, Vincenzo

    2015-01-01

    Unlike most of the work-related stress research, which emphasizes how to manage stressors and maximize the psychological well-being, the present article focuses on one particular kind of stressor: the experience of conflict or interference between demands at work and responsibilities and commitments outside of the work setting, especially in respect offamily life and one's personal life. Referred to as "work-family conflict" or (more recently) "work-life conflict", this stressor has been demonstrated in research since the 1990s to exert a considerable impact on individuals' well-being along with other areas such as family functioning and even performance on the job. In contrast to the intra-role conflict, which refers to interference between roles within a single domain (e.g., the work context), work-family (or work-life) conflict is a form of inter-role interference which occurs when there is conflict across domains. In the 1980s and 1990s, research and writing in this area focused predominantly on work versus family, but in recent years the "non-work" component has been expanded to include other aspects of people's lives. For simplicity, we will refer to the two major spheres as the "work domain" (i.e., a person's paid employment) and the "life domain" (which comprises all other dimensions of life, including family, recreation, community activities and personal life). Although this classification is not entirely appropriate, it enables differentiation between the two spheres.

  13. Finite element analysis of stress concentration in three popular brands of fiber posts systems used for maxillary central incisor teeth.

    Science.gov (United States)

    Aggarwal, Shalini; Garg, Vaibhav

    2011-07-01

    To study the stress concentrations in endodontically treated maxillary central incisor teeth restored with 3 different fiber post systems subjected to various oblique occlusal loads. FEM analysis was used to analyze stress concentrations generated in maxillary anterior teeth. Computer aided designing was used to create a 2-D model of an upper central incisor. Post systems analyzed were the DT Light Post (RDT, Bisco), Luscent Anchor (Dentatus) & RelyX (3M-ESPE). The entire design assembly was subjected to analysis by ANSYS for oblique loading forces of 25N, 80N & 125 N RESULTS: The resultant data showed that the RelyX generated the least amount of stress concentration. Minimal stress buildups contribute to the longevity of the restorations. Thus RelyX by virtue of judicious stress distribution is the better option for restoration of grossly decayed teeth.

  14. Straightened cervical lordosis causes stress concentration: a finite element model study

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wei; Shi, Shiyuan; Fei, Jun; Wang, Yifan; Chen, Chunyue [Hangzhou Red Cross Hospital, Hangzhou, Zhejiang, (China); Liao, Shenhui [School of Information Science and Engineering, Central South University, Changsha, Hunan (China)

    2013-03-15

    In this study, we propose a finite element analysis of the complete cervical spine with straightened and normal physiological curvature by using a specially designed modelling system. An accurate finite element model is established to recommend plausible approaches to treatment of cervical spondylosis through the finite element analysis results. There are few reports of biomechanics influence of the straightened cervical curve. It is difficult to measure internal responses of cervical spine directly. However, the finite element method has been reported to have the capability to quantify both external and internal responses to mechanical loading, such as the strain and stress distribution of spinal components. We choose a subject with a straightened cervical spine from whom to collect the CT scan data, which formed the basis of the finite element analysis. By using a specially designed modelling system, a high quality finite element model of the complete cervical spine with straightened curvature was generated, which was then mapped to reconstruct a normal physiological curvature model by a volumetric mesh deformation method based on discrete differential properties. Then, the same boundary conditions were applied to do a comparison. The result demonstrated that the active movement range of straightened cervical spine decreased by 24–33 %, but the stress increased by 5–95 %. The stress was concentrated at the facet joint cartilage, uncovertebral joint and the disk. The results suggest that cervical lordosis may have a direct impact on cervical spondylosis treatment. These results may be useful for clinical treatment of cervical spondylosis with straightened curvature.

  15. Straightened cervical lordosis causes stress concentration: a finite element model study

    International Nuclear Information System (INIS)

    Wei, Wei; Shi, Shiyuan; Fei, Jun; Wang, Yifan; Chen, Chunyue; Liao, Shenhui

    2013-01-01

    In this study, we propose a finite element analysis of the complete cervical spine with straightened and normal physiological curvature by using a specially designed modelling system. An accurate finite element model is established to recommend plausible approaches to treatment of cervical spondylosis through the finite element analysis results. There are few reports of biomechanics influence of the straightened cervical curve. It is difficult to measure internal responses of cervical spine directly. However, the finite element method has been reported to have the capability to quantify both external and internal responses to mechanical loading, such as the strain and stress distribution of spinal components. We choose a subject with a straightened cervical spine from whom to collect the CT scan data, which formed the basis of the finite element analysis. By using a specially designed modelling system, a high quality finite element model of the complete cervical spine with straightened curvature was generated, which was then mapped to reconstruct a normal physiological curvature model by a volumetric mesh deformation method based on discrete differential properties. Then, the same boundary conditions were applied to do a comparison. The result demonstrated that the active movement range of straightened cervical spine decreased by 24–33 %, but the stress increased by 5–95 %. The stress was concentrated at the facet joint cartilage, uncovertebral joint and the disk. The results suggest that cervical lordosis may have a direct impact on cervical spondylosis treatment. These results may be useful for clinical treatment of cervical spondylosis with straightened curvature.

  16. High Pb concentration stress on Typha latifolia growth and Pb removal in microcosm wetlands.

    Science.gov (United States)

    Han, Jianqiu; Chen, Fengzhen; Zhou, Yumei; Wang, Chaohua

    2015-01-01

    When constructed wetlands are used to treat high-Pb wastewater, Pb may become a stress to wetland plants, which subsequently reduces treatment performance and the other ecosystem services. To facilitate the design and operation of constructed wetlands for treatment of Pb-rich wastewater, we investigated the irreversible inhibitory level of Pb for Typha latifolia through experiments in microcosm wetlands. Seven horizontal subsurface flow constructed wetlands were built with rectangular plastic tanks and packed with marble chips and sand. All wetlands were transplanted with nine stems of Typha latifolia each. The wetlands were batch operated in a greenhouse with artificial wastewater (10 L each) for 12 days. Influent to the seven wetlands had different concentrations of Pb: 0 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L, and 500 mg/L, respectively. The results suggested that leaf chlorophyll relative content, relative growth rate, photosynthetic characteristics, activities of superoxide dismutase, peroxidase, and content of malondialdehyde were not affected when initial Pb concentration was at 100 mg/L and below. But when initial Pb concentration was above 100 mg/L, all of them were seriously affected. We conclude that high Pb concentrations wastewater could inhibit the growth of Typha latifolia and decrease the removal rate of wetlands.

  17. Usefulness of dipyridamole stress myocardial imaging in patients who have exercise limitations due to various orthopedic disorders

    International Nuclear Information System (INIS)

    Tagawa, Hirofumi; Ashihara, Toshiaki; Fukuyama, Takaya; Matsui, Kanji; Yamamoto, Sumiki; Yamamoto, Susumu

    1994-01-01

    To evaluate the presence of coronary artery disease in patients unable to exercise adequately because of chronic rheumatoid arthritis, osteoarthritis, hip bone fractures or disk herniation, we performed dipyridamole-stress thallium-201 myocardial imaging in thirty-three patients. Twelve of the 33 patients showed perfusion defect and redistribution by thallium imaging. Coronary angiography was performed in 9 patients out of these 12 dipyridamole-positive patients and significant coronary artery stenosis was detected in 7 of them (78%). Due to these results of dipyridamole-imaging and coronary angiograms, surgical intervention for the underlying bone or joint disorder was performed under cardioprotective strategy in 15 patients, in which no cardiovascular events occurred. Thus, dipyridamole-stress myocardial imaging is a satisfactory alternative to the exercise test for detecting coronary artery disease in patients with bone or joint disorders. (author)

  18. On the mechanical stress of Zr, Zry, and other materials due to the formation of oxide layers

    International Nuclear Information System (INIS)

    Hofmann, P.

    1977-06-01

    Several mechanisms are indicated which during oxidation of sheets, tubes, and cylinders of pure metals and alloys might lead to plastic deformation of the remaining uncorroded cross section. Some experimental methods are described which allow evaluation of stresses occurring in oxide layers. The main reason for the creep deformation of flat and tubular specimens made of Zr and Zr alloys lies in the stresses that arise from volume increase due to the growth of oxide layers. Plastic deformations of the sheet metal specimens can be up to 100% and are anisotropic. In tubular specimens the changes in geometry (axial, radial) are much smaller in the course of oxidation and attain 2% at the maximum for Zr- or Zry-tubes and go up to 10% for Ta-tubes when no differential pressure is applied simultaneously. (orig.) [de

  19. Oxidative Stress at High Temperatures in Lactococcus lactis Due to an Insufficient Supply of Riboflavin

    Science.gov (United States)

    Chen, Jun; Shen, Jing

    2013-01-01

    Lactococcus lactis MG1363 was found to be unable to grow at temperatures above 37°C in a defined medium without riboflavin, and the cause was identified to be dissolved oxygen introduced during preparation of the medium. At 30°C, growth was unaffected by dissolved oxygen and oxygen was consumed quickly. Raising the temperature to 37°C resulted in severe growth inhibition and only slow removal of dissolved oxygen. Under these conditions, an abnormally low intracellular ratio of [ATP] to [ADP] (1.4) was found (normally around 5), which indicates that the cells are energy limited. By adding riboflavin to the medium, it was possible to improve growth and oxygen consumption at 37°C, and this also normalized the [ATP]-to-[ADP] ratio. A codon-optimized redox-sensitive green fluorescent protein (GFP) was introduced into L. lactis and revealed a more oxidized cytoplasm at 37°C than at 30°C. These results indicate that L. lactis suffers from heat-induced oxidative stress at increased temperatures. A decrease in intracellular flavin adenine dinucleotide (FAD), which is derived from riboflavin, was observed with increasing growth temperature, but the presence of riboflavin made the decrease smaller. The drop was accompanied by a decrease in NADH oxidase and pyruvate dehydrogenase activities, both of which depend on FAD as a cofactor. By overexpressing the riboflavin transporter, it was possible to improve FAD biosynthesis, which resulted in increased NADH oxidase and pyruvate dehydrogenase activities and improved fitness at high temperatures in the presence of oxygen. PMID:23913422

  20. Proline accumulation in lemongrass (Cymbopogon flexuosus Stapf.) due to heavy metal stress.

    Science.gov (United States)

    Handique, G K; Handique, A K

    2009-03-01

    Toxic heavy metals viz. lead, mercury and cadmium induced differential accumulation of proline in lemongrass (Cymbopogon flexuosus Stapf.) grown in soil amended with 50, 100, 200, 350 and 500 mg kg(-1) of the metals have been studied. Proline accumulation was found to be metal specific, organ specific and linear dose dependant. Further, proline accumulation following short term exposure (two months after transplantation) was higher than long term exposure (nine months after transplantation). Proline accumulation following short term exposure was 2.032 to 3.839 micro moles g(-1) for cadmium (50-200 mg kg(-1)); the corresponding range for mercury was 1.968 to 5.670 micro moles g(-1) and 0.830 to 4.567 micro moles g(-1) for lead (50-500 mg kg(-1) for mercury and lead). Proline accumulation was consistently higher in young tender leaf than old leaf, irrespective of the metal or duration of exposure. For cadmium treatment proline level was 2.032 to 3.839 micro moles g(-1) for young leaves while the corresponding value for old leaf was 1.728 to 2.396 micro moles g(-1) following short term exposure. The same trend was observed for the other two metals and duration of exposure. For control set proline accumulation in root was 0.425 micro moles g(-1) as against 0.805 and 0.533 micro moles g(-1) in young and old leaves respectively indicating that proline accumulation in root are lower than leaves, under both normal and stressed condition.

  1. The water avoidance stress induces bladder pain due to a prolonged alpha1A adrenoceptor stimulation.

    Science.gov (United States)

    Matos, Rita; Serrão, Paula; Rodriguez, Larissa; Birder, Lori Ann; Cruz, Francisco; Charrua, Ana

    2017-08-01

    Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) remains an elusive disease with the cause for the pain unclear. BPS/IC patients present increased sympathetic activity and high levels of urinary noradrenaline. At the experimental level, it has been shown that chronic adrenergic stimulation produces pain and bladder changes through an alpha 1A adrenoceptor mediated mechanism. Water avoidance stress (WAS) in rodents reproduces signs of nociception and bladder changes seen in BPS/IC patients. In this study, we explore the possible role of alpha 1A adrenoceptor in bladder pain and morphological changes. WAS was induced in a group of female Wistar rats. A separate WAS group received 0.2 mg/kg day silodosin (WAS + S). Lower abdominal pain was determined by performing sensitivity to Von Frey filaments. Bladder reflex activity was determined by cystometry in anaesthetised animals. Urine was collected for noradrenaline quantification by HPLC. Bladders were harvested and stained with Haematoxylin-eosin (to analyse urothelial morphology and to determine the disruption of surface umbrella cells) or with Toluidine Blue 0.1% to analyse mast cell infiltration. WAS increased urinary noradrenaline level and bladder frequency and decreased mechanical pain threshold, which was reversed by silodosin. WAS induced lymphocytic and mast cells infiltration in the mucosa and mild urothelial disruption, which was absent in WAS + S group. Alpha 1A adrenoceptor stimulation has an important role in the appearance of bladder pain in rats. Since BPS/IC patients present high levels of noradrenaline, alpha 1A stimulation may be an additional trigger for bladder dysfunction presented by these patients. Further studies will determine the clinical relevance of this finding in the treatment of BPS/IC patients.

  2. [MELATONIN CONCENTRATION IN THE BLOOD OF VITILIGO PATIENTS WITH STRESS IN ANAMNESIS].

    Science.gov (United States)

    Tsiskarishvili, N I; Katsitadze, A; Tsiskarishvili, N V; Tsiskarishvil, Ts; Chitanava, L

    2016-05-01

    In recent years, despite some progress in the study of vitiligo many aspects of pathogenesis and treatment of this dermatosis remain unsolved or are highly controversial. It is believed that progression of disease is associated with a genetic predisposition, autoimmune processes and oxidative stress, but the concrete role of stress on the processes having place in the organism of vitiligo patients so far is not investigated. As we know, epiphysis is the main regulator of adaptation of the individual to the environment. An important product of secretion of the pineal gland is the hormone melatonin - a universal regulator of vital functions and biorhythms of the body. Psychoses, neuroses, depression, immunopathology are aspects of disturbances in circadian, seasonal and annual rhythms of the synthesis of this hormone. Clinical and experimental studies indicate that the hormone melatonin, which is one of the links in a stress defense mechanism of the body, has antioxidant and immunomodulatory properties. The purpose of this study was to determine plasma level of melatonin in the blood of vitiligo patients (with stress in anamnesis), depending on the clinical form and duration of the disease. 41 patients with vitiligo (16 with segmental and 25 with non-segmental form) with stress in anamnesis and duration of disease from several months to 20 years were under observation. The level of melatonin in the blood plasma was determined by ELISA (IBL - international - reagent), the results were expressed in units of pg/ml. According to the results of our study, 8 patients with segmental vitiligo had the normal level of plasma melatonin concentration (in the range of 20.2-31.1 pg/ml), in 2 cases - the level was near the norm (19.2 pg/ml). In the group of patients with non-segmental vitiligo, the level of melatonin was below the norm (12.5 pg/ml) and in 2 cases, the content of melatonin was very low - 4.05 pg / ml. Correlation analysis of melatonin levels with duration of disease

  3. Phase-matched light amplification by three-wave mixing process in a birefringent fiber due to externally applied stress

    International Nuclear Information System (INIS)

    Ohashi, M.; Kitayama, K.; Ishida, Y.; Uchida, N.

    1982-01-01

    A novel method to achieve phase-matched light amplification in a birefringent fiber via the three-wave mixing is proposed by using frequency shift change due to the stress applied to the fiber. It is confirmed that the signal power from a cw laser diode at lambda = 1.292 μm is amplified by 6.1 x 10 3 times in the birefringent fiber pumped with a Q-switched Nd: yttrium aluminum garnet laser at lambda = 1.064 μm. This will provide a new fiber-optic light signal amplifier having a good tolerance for variation of signal wavelengths

  4. Posttraumatic Stress Disorder After Bereavement: Early Psychological Sequelae of Losing a Close Relative Due to Terminal Cancer

    DEFF Research Database (Denmark)

    Kristensen, T. E.; Elklit, A.; Karstoft, K. I.

    2012-01-01

    Very few studies have investigated posttraumatic stress disorder (PTSD) as a consequence of bereavement from terminal illness. Therefore, knowledge on the traumatizing effects of bereavement and risk factors for traumatization from bereavement is rather sparse. This study investigated prevalence...... and predictors of PTSD in a group of people who had recently lost a close relative due to incurable cancer. The participants were 132 persons who were assessed with the Harvard Trauma Questionnaire, the Trauma Symptom Checklist, and the Crisis Support Scale. One month after the loss, 29.5% of the subjects had...

  5. Attenuation of Microbial Stress Due to Nano-Ag and Nano-TiO2 Interactions under Dark Conditions.

    Science.gov (United States)

    Wilke, Carolyn M; Tong, Tiezheng; Gaillard, Jean-François; Gray, Kimberly A

    2016-10-04

    Engineered nanomaterials (ENMs) are incorporated into thousands of commercial products, and their release into environmental systems creates complex mixtures with unknown toxicological outcomes. To explore this scenario, we probe the chemical and toxicological interactions of nanosilver (n-Ag) and nanotitania (n-TiO 2 ) in Lake Michigan water, a natural aqueous medium, under dark conditions. We find that the presence of n-Ag induces a stress response in Escherichia coli, as indicated by a decrease in ATP production observed at low concentrations (in the μg L -1 range), with levels that are environmentally relevant. However, when n-Ag and n-TiO 2 are present together in a mixture, n-TiO 2 attenuates the toxicity of n-Ag at and below 20 μg L -1 by adsorbing Ag + (aq) . We observe, however, that toxic stress cannot be explained by dissolved silver concentrations alone and, therefore, must also depend on silver associated with the nanoscale fraction. Although the attenuating effect of n-TiO 2 on n-Ag's toxicity is limited, this study emphasizes the importance of probing the toxicity of ENM mixtures under environmental conditions to assess how chemical interactions between nanoparticles change the toxicological effects of single ENMs in unexpected ways.

  6. Oxidative stress due to radiation in CD34+ hematopoietic progenitor cells. Protection by IGF-1

    International Nuclear Information System (INIS)

    Floratou, K.; Karakantza, M.; Giannopoulou, E.; Antonacopoulou, A.; Adonakis, G.; Kardamakis, D.; Matsouka, P.

    2012-01-01

    Radiation exerts direct as well as indirect effects on DNA through the generation of reactive oxygen species (ROS). Irradiated hematopoietic progenitor cells (HPCs) experience DNA strand breaks, favoring genetic instability, due to ROS generation. Our aim was to study the effect of a range of radiation doses in HPCs and the possible protective mechanisms activated by insulin-like growth factor-1 (IGF-1). ROS generation was evaluated, in the presence or absence of IGF-1 in liquid cultures of human HPCs-CD34 + irradiated with 1-, 2- and 5-Gy X-rays, using a flow cytometry assay. Manganese superoxide dismutase (MnSOD) expression was studied by western blot analysis and visualized by an immunofluorescence assay. Apoptosis was estimated using the following assays: Annexin-V assay, DNA degradation assay, BCL-2/BAX mRNA and protein levels and caspase-9 protein immunofluorescence visualization. Viability and clonogenic potential were studied in irradiated HPCs. The generation of superoxide anion radicals at an early and a late time point was increased, while the hydrogen peroxide generation at a late time point was stable. IGF-1 presence further enhanced the radiation-induced increase of MnSOD at 24 h post irradiation. IGF-1 inhibited the mitochondria-mediated pathway of apoptosis by regulating the m-RNA and protein expression of BAX, BCL-2 and the BCL-2/BAX ratio and by decreasing caspase-9 protein expression. IGF-1 presence in culture media of irradiated cells restored the clonogenic capacity and the viability of HPCs as well. In conclusion, IGF-1 protects HPCs-CD34 + from radiation effects, by eliminating the oxidative microenvironment through the enhancement of MnSOD activation and by regulating the mitochondria-mediated pathway of apoptosis. (author)

  7. Impact of trace metal concentrations on coccolithophore growth and morphology: laboratory simulations of Cretaceous stress

    Science.gov (United States)

    Faucher, Giulia; Hoffmann, Linn; Bach, Lennart T.; Bottini, Cinzia; Erba, Elisabetta; Riebesell, Ulf

    2017-07-01

    The Cretaceous ocean witnessed intervals of profound perturbations such as volcanic input of large amounts of CO2, anoxia, eutrophication and introduction of biologically relevant metals. Some of these extreme events were characterized by size reduction and/or morphological changes of a few calcareous nannofossil species. The correspondence between intervals of high trace metal concentrations and coccolith dwarfism suggests a negative effect of these elements on nannoplankton biocalcification processes in past oceans. In order to test this hypothesis, we explored the potential effect of a mixture of trace metals on growth and morphology of four living coccolithophore species, namely Emiliania huxleyi, Gephyrocapsa oceanica, Pleurochrysis carterae and Coccolithus pelagicus. The phylogenetic history of coccolithophores shows that the selected living species are linked to Mesozoic species showing dwarfism under excess metal concentrations. The trace metals tested were chosen to simulate the environmental stress identified in the geological record and upon known trace metal interactions with living coccolithophore algae.Our laboratory experiments demonstrated that elevated trace metal concentrations, similarly to the fossil record, affect coccolithophore algae size and/or weight. Smaller coccoliths were detected in E. huxleyi and C. pelagicus, while coccoliths of G. oceanica showed a decrease in size only at the highest trace metal concentrations. P. carterae coccolith size was unresponsive to changing trace metal concentrations. These differences among species allow discriminating the most- (P. carterae), intermediate- (E. huxleyi and G. oceanica) and least-tolerant (C. pelagicus) taxa. The fossil record and the experimental results converge on a selective response of coccolithophores to metal availability.These species-specific differences must be considered before morphological features of coccoliths are used to reconstruct paleo-chemical conditions.

  8. Impact of trace metal concentrations on coccolithophore growth and morphology: laboratory simulations of Cretaceous stress

    Directory of Open Access Journals (Sweden)

    G. Faucher

    2017-07-01

    Full Text Available The Cretaceous ocean witnessed intervals of profound perturbations such as volcanic input of large amounts of CO2, anoxia, eutrophication and introduction of biologically relevant metals. Some of these extreme events were characterized by size reduction and/or morphological changes of a few calcareous nannofossil species. The correspondence between intervals of high trace metal concentrations and coccolith dwarfism suggests a negative effect of these elements on nannoplankton biocalcification processes in past oceans. In order to test this hypothesis, we explored the potential effect of a mixture of trace metals on growth and morphology of four living coccolithophore species, namely Emiliania huxleyi, Gephyrocapsa oceanica, Pleurochrysis carterae and Coccolithus pelagicus. The phylogenetic history of coccolithophores shows that the selected living species are linked to Mesozoic species showing dwarfism under excess metal concentrations. The trace metals tested were chosen to simulate the environmental stress identified in the geological record and upon known trace metal interactions with living coccolithophore algae.Our laboratory experiments demonstrated that elevated trace metal concentrations, similarly to the fossil record, affect coccolithophore algae size and/or weight. Smaller coccoliths were detected in E. huxleyi and C. pelagicus, while coccoliths of G. oceanica showed a decrease in size only at the highest trace metal concentrations. P. carterae coccolith size was unresponsive to changing trace metal concentrations. These differences among species allow discriminating the most- (P. carterae, intermediate- (E. huxleyi and G. oceanica and least-tolerant (C. pelagicus taxa. The fossil record and the experimental results converge on a selective response of coccolithophores to metal availability.These species-specific differences must be considered before morphological features of coccoliths are used to reconstruct paleo-chemical conditions.

  9. Concentration-dependent toxicity of iron oxide nanoparticles mediated by increased oxidative stress

    Directory of Open Access Journals (Sweden)

    Saba Naqvi

    2010-11-01

    Full Text Available Saba Naqvi1, Mohammad Samim2, MZ Abdin3, Farhan Jalees Ahmed4, AN Maitra5, CK Prashant6, Amit K Dinda61Faculty of Engineering and Interdisciplinary Sciences, 2Department of Chemistry, 3Department of Biotechnology, Faculty of Science, 4Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, Hamdard University, 5Department of Chemistry, University of Delhi, 6Department of Pathology, All India Institute of Medical Sciences, New Delhi, IndiaAbstract: Iron oxide nanoparticles with unique magnetic properties have a high potential for use in several biomedical, bioengineering and in vivo applications, including tissue repair, magnetic resonance imaging, immunoassay, drug delivery, detoxification of biologic fluids, cell sorting, and hyperthermia. Although various surface modifications are being done for making these nonbiodegradable nanoparticles more biocompatible, their toxic potential is still a major concern. The current in vitro study of the interaction of superparamagnetic iron oxide nanoparticles of mean diameter 30 nm coated with Tween 80 and murine macrophage (J774 cells was undertaken to evaluate the dose- and time-dependent toxic potential, as well as investigate the role of oxidative stress in the toxicity. A 15–30 nm size range of spherical nanoparticles were characterized by transmission electron microscopy and zeta sizer. MTT assay showed >95% viability of cells in lower concentrations (25–200 µg/mL and up to three hours of exposure, whereas at higher concentrations (300–500 µg/mL and prolonged (six hours exposure viability reduced to 55%–65%. Necrosis-apoptosis assay by propidium iodide and Hoechst-33342 staining revealed loss of the majority of the cells by apoptosis. H2DCFDDA assay to quantify generation of intracellular reactive oxygen species (ROS indicated that exposure to a higher concentration of nanoparticles resulted in enhanced ROS generation, leading to cell injury and death. The cell membrane injury

  10. Early stress responses in Atlantic salmon (Salmo salar) exposed to environmentally relevant concentrations of uranium

    International Nuclear Information System (INIS)

    Song You; Salbu, Brit; Heier, Lene Sørlie; Teien, Hans-Christian; Lind, Ole-Christian; Oughton, Deborah; Petersen, Karina; Rosseland, Bjørn Olav; Skipperud, Lindis; Tollefsen, Knut Erik

    2012-01-01

    Uranium (U) is a naturally occurring heavy metal widely used in many military and civil applications. Uranium contamination and the associated potential adverse effects of U on the aquatic environment have been debated during recent years. In order to understand the effect and mode of action (MoA) of U in vivo, juvenile Atlantic salmon (Salmo salar) were exposed to 0.25 mg/L, 0.5 mg/L and 1.0 mg/L waterborne depleted uranyl acetate, respectively, in a static system for 48 h. The U concentrations in the gill and liver were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and the resulting biological effects were determined by a combination of analysis of gene expression and micronuclei formation. The hepatic transcriptional level of 12 biomarker genes from four stress–response categories, including oxidative stress (γ-glutamyl cysteine synthetase (GCS), glutathione reductase (GR), glutathione peroxidase (GPx)), DNA damage and repair (P53, cyclin-dependent kinase inhibitor 1 (P21), growth arrest and DNA damage-inducible gene gamma (Gadd45G), proliferating cell nuclear antigen (PCNA), Rad51), apoptosis (Bcl2-associated X protein (BAX), Bcl-x, Caspase 6A,) and protein degradation (Ubiquitin) were evaluated by quantitative real-time polymerase chain reaction (q-rtPCR). The results clearly showed accumulation of U in the gill and liver with increasing concentrations of U in the exposure water. The effects of U on differential hepatic gene expression also occurred in a concentration-dependent manner, although deviations from ideal concentration–response relationships were observed at the highest U concentration (1.0 mg/L). All the genes tested were found to be up-regulated by U while no significant micronuclei formation was identified. The results suggest that U may cause oxidative stress in fish liver at concentrations greater than 0.25 mg/L, giving rise to clear induction of several toxicologically relevant biomarker genes, although no significant

  11. Post-traumatic stress disorder in Polish stroke patients who survived Nazi concentration camps.

    Science.gov (United States)

    Pachalska, Maria; Grochmal-Bach, Bozena; MacQueen, Bruce Duncan; Frańczuk, Bogusław

    2006-04-01

    Many persons who survived Nazi concentration camps are now in advanced age, so that rehabilitation centers in Poland are seeing increasing numbers of such patients, especially after strokes. In many cases, the process of rehabilitation is severely hampered by Post-Traumatic Stress Disorder (PTSD), while the neuropsychological consequences of the stroke itself often evoke traumatic memories and simultaneously disorganize or destroy the patient's previous coping mechanisms. The present study describes the program developed by the authors for concentration camp survivors in post-stroke rehabilitation, including the use of art therapy and specially prepared films to help the patients cope with PTSD. The experimental group (KL) consisted of 8 such patients (4 men, 4 women, average age 79.1+/-4.28) with mild post-stroke aphasia who went through the PTSD program, while the comparison group (C) included 8 post-stroke patients, matched for age and gender, who were not concentration camp survivors and showed no premorbid symptoms of PTSD. All subjects were tested at baseline and again 3 months later, using structured interview and observation, self-rating scales for three basic negative emotions (anger, anxiety and sadness) and the Frustration and Aggression Test for the Disabled. The results showed significant differences between the groups at baseline, while at follow-up the differences between groups had changed in both extent and distribution. Qualitative analysis of the results allows for some important observations about the etiology and course of PTSD in these persons.

  12. Two different mechanisms of fatigue damage due to cyclic stress loading at 77 K for MOCVD-YBCO-coated conductors

    International Nuclear Information System (INIS)

    Sugano, M; Yoshida, Y; Hojo, M; Shikimachi, K; Hirano, N; Nagaya, S

    2008-01-01

    Tensile fatigue tests were carried out at 77 K for YBCO-coated conductors fabricated by metal-organic chemical vapor deposition (MOCVD). The S-N relationship, variation of critical current (I c ) during cyclic loading and microscopic fatigue damage were investigated. Fatigue strength at 10 6 cycles was evaluated to be σ max = 1300 MPa and 890 MPa under the stress ratios of 0.5 and 0.1. Two different mechanisms of fatigue damage, depending on the number of stress cycles to failure, were observed. In one of the fracture mechanisms, fatigue behavior is characterized by overall fracture which occurs at 10 4 -10 5 cycles. For these specimens, I c after unloading does not degrade before overall fracture. Although only shallow slip bands were found at the Ag surface, fatigue cracks were found on the Hastelloy C-276 surface of the fractured specimen. These results suggest that overall fracture due to cyclic stress was caused by fatigue of the Hastelloy substrate. In the other fracture mechanism, even though overall fracture did not occur at 10 6 cycles, a slight decrease of I c was detected after 10 5 cycles. No fatigue crack was found on the Hastelloy surface, while deep slip bands corresponding to the initial stage of fatigue crack were observed on the Ag surface. From these results, we concluded that I c degradation at a high cycle number is attributed to the fatigue of the Ag stabilizing layer

  13. Psychometric characteristics of the Eating and Appraisal Due to Emotions and Stress Questionnaire and obesity in Mexican university students.

    Science.gov (United States)

    Lazarevich, Irina; Irigoyen-Camacho, María Esther; Velazquez-Alva, María del Consuelo; Salinas-Ávila, Jaqueline

    2015-06-01

    Emotional eating has been defined as eating in a response to negative emotions and it is associated with weight gain. The English version of Eating Appraisal Due to Emotions and Stress Questionnaire (EADES) was developed to assess how individuals use food in order to cope with stress and emotions. To analyze psychometric characteristics of Spanish version of EADES and to identify whether the constructs of EADES were associated with obesity in university students. The EADES (Spanish version) was administered to 232 Mexican university students from 18 to 29 years old. Body Mass Index (BMI) was calculated. A test-retest evaluation was conducted with 75 participants. Cronbach's alpha of EADES was 0.92; the interclass correlation coefficient was 0.88. Regarding BMI and EADES results, the subscale Emotion and Stress Related Eating was significantly associated with obesity (p = 0.026). Through factor analysis of the instrument, three factors were extracted and items that showed factor loading obesity and the 40-items version of the instrument, a statistically significance association was found for the total score (OR = 0.973, p = 0.020) and for the factor Self-confidence related to Emotional Eating component (OR = 0.940, p = 0.026). A good internal consistency and temporal stability of the Spanish version of the instrument were found; the 40-item EADES version was positively associated with obesity. This instrument could be useful in assessing emotional eating. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  14. Comorbidity in illness-induced posttraumatic stress disorder versus posttraumatic stress disorder due to external events in a nationally representative study.

    Science.gov (United States)

    Sommer, Jordana L; Mota, Natalie; Edmondson, Donald; El-Gabalawy, Renée

    2018-05-10

    The current study compared physical and mental health characteristics and quality of life of illness-induced posttraumatic stress disorder (PTSD) versus those with PTSD due to external traumatic events in a population-based sample. PTSD was assessed with the Alcohol Use Disorder and Associated Disabilities Interview Schedule (AUDADIS-5) using DSM-5 criteria in the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions. Participants with past-year PTSD (n = 1779) were categorized into two groups: illness-induced (6.5%) and other trauma-induced PTSD (92.9%) based on index trauma. Group differences in physical health, mental health, and quality of life were estimated using multiple logistic and linear regressions with adjustment for demographics and medical morbidity. Compared to PTSD due to external events, illness-induced PTSD had higher rates of life-threatening illness in the past year. Illness-induced PTSD compared to PTSD due to external events was associated with reduced odds of depressive/bipolar disorders and antisocial personality disorder, but increased odds of cannabis use disorder. The groups did not differ on quality of life after accounting for medical morbidity. Illness-induced PTSD is common among American adults and has a similar impact on quality of life as PTSD due to external events, but may have distinct mental health correlates. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Two-dimensional concentrated-stress low-frequency piezoelectric vibration energy harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Sharpes, Nathan [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Abdelkefi, Abdessattar [Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2015-08-31

    Vibration-based energy harvesters using piezoelectric materials have long made use of the cantilever beam structure. Surmounting the deficiencies in one-dimensional cantilever-based energy harvesters has been a major focus in the literature. In this work, we demonstrate a strategy of using two-dimensional beam shapes to harvest energy from low frequency excitations. A characteristic Zigzag-shaped beam is created to compare against the two proposed two-dimensional beam shapes, all of which occupy a 25.4 × 25.4 mm{sup 2} area. In addition to maintaining the low-resonance bending frequency, the proposed beam shapes are designed with the goal of realizing a concentrated stress structure, whereby stress in the beam is concentrated in a single area where a piezoelectric layer may be placed, rather than being distributed throughout the beam. It is shown analytically, numerically, and experimentally that one of the proposed harvesters is able to provide significant increase in power production, when the base acceleration is set equal to 0.1 g, with only a minimal change in the resonant frequency compared to the current state-of-the-art Zigzag shape. This is accomplished by eliminating torsional effects, producing a more pure bending motion that is necessary for high electromechanical coupling. In addition, the proposed harvesters have a large effective beam tip whereby large tip mass may be placed while retaining a low-profile, resulting in a low volume harvester and subsequently large power density.

  16. Increases in aerosol concentrations over eastern China due to the decadal-scale weakening of the East Asian summer monsoon

    Science.gov (United States)

    Zhu, Jianlei; Liao, Hong; Li, Jianping

    2012-05-01

    China has been experiencing increased concentrations of aerosols, commonly attributed to the large increases in emissions associated with the rapid economic development. We show by using a chemical transport model driven by the assimilated meteorological fields that the observed decadal-scale weakening of the East Asian summer monsoon also contributed to the increases in aerosols in China. We find that the simulated aerosol concentrations have strong negative correlations with the strength of the East Asian Summer monsoon. Accounting for sulfate, nitrate, ammonium, black carbon, and organic carbon aerosols, the summer surface-layer PM2.5 concentration averaged over eastern China (110°-125°E, 20°-45°N) can be 17.7% higher in the weakest monsoon years than in the strongest monsoon years. The weakening of the East Asian Summer monsoon increases aerosol concentrations mainly by the changes in atmospheric circulation (the convergence of air pollutants) in eastern China.

  17. Response of plants to high concentrations of uranium stress and the screening of remediation plants

    International Nuclear Information System (INIS)

    Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

    2013-01-01

    Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

  18. XML Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

    Directory of Open Access Journals (Sweden)

    M. R. Monazzam Esmaielpou

    2015-09-01

    Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced

  19. Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

    Directory of Open Access Journals (Sweden)

    M. R. Monazzam Esmaielpour

    2015-09-01

    Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. . Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. .Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. .Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is

  20. Zeolites relieves inhibitory stress from high concentrations of long chain fatty acids.

    Science.gov (United States)

    Nordell, Erik; Hansson, Anna B; Karlsson, Martin

    2013-12-01

    Protein and fat rich slaughterhouse waste is a very attractive waste stream for the production of biogas because of the high biochemical methane potential of the substrate. The material has however some drawbacks as the sole material for biogas production due to the production of several process disturbing metabolites such as ammonia, sulfides and long chain fatty acids. We can in this work present results that show that zeolites have the potential to relieve inhibitory stress from the presence of long chain fatty acids. Moreover, the results strongly indicate that it is mainly acetic acid consumers that are most negatively affected by long chain fatty acids and that the mechanism of stress relief is an adsorption of long chain fatty acids to the zeolites. In addition to this, it is shown that the effect is immediate and that only a small amount of zeolites is necessary to cancel the inhibitory effect of long chain fatty acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Monitoring Changes in Croplands Due to Water Stress in the Krishna River Basin Using Temporal Satellite Imagery

    Directory of Open Access Journals (Sweden)

    Venkata Ramana Murthy Reddi

    2017-10-01

    Full Text Available Remote sensing-based assessments of large river basins such as the Krishna, which supplies water to many states in India, are useful for operationally monitoring agriculture, especially basins that are affected by abiotic stress. Moderate-Resolution Imaging Spectroradiometer (MODIS time series products can be used to understand cropland changes at the basin level due to abiotic stresses, especially water scarcity. Spectral matching techniques were used to identify land use/land cover (LULC areas for two crop years: 2013–2014, which was a normal year, and 2015–2016, which was a water stress year. Water stress-affected crop areas were categorized into three classes—severe, moderate and mild—based on the normalized difference vegetation index (NDVI and intensity of damage assessed through field sampling. Furthermore, ground survey data were used to assess the accuracy of MODIS-derived classification individual products. Water inflows into and outflows from the Krishna river basin during the study period were used as direct indicators of water scarcity/availability in the Krishna Basin. Furthermore, ground survey data were used to assess the accuracy of MODIS-derived LULC classification of individual year products. Rainfall data from the tropical rainfall monitoring mission (TRMM was used to support the water stress analysis. The nine LULC classes derived using the MODIS temporal imagery provided overall accuracies of 82% for the cropping year 2013–2014 and 85% for the year 2015–2016. Kappa values are 0.78 for 2013–2014 and 0.82 for 2015–2016. MODIS-derived cropland areas were compared with national statistics for the cropping year 2013–2014 with a R2 value of 0.87. Results show that both rainfed and irrigated areas in 2015–2016 saw significant changes that will have significant impacts on food security. It has been also observed that the farmers in the basin tend to use lower inputs and labour per ha during drought years. Among

  2. A sensitivity study on neutron flux variation due to 10B concentration in dose calculation for BNCT

    International Nuclear Information System (INIS)

    Jung, Sang Hoon

    2006-02-01

    The effects of inclusion of 10 B concentration on neutron flux and dose in dose calculation were studied. In order to provide the quantitative effects of inclusion of 10 B concentrations on depressions of neutron and photon flux and dose, the fluxes and doses with voxel head phantoms for various 10 B concentrations homogeneously distributed were calculated by using MCNPX simulations. A lithium target system and beam shaping assembly, which have been developed at the Hanyang University, were used as epithermal neutron beam. The calculation results show that the neutron flux at the center of the head phantom decreases by approximately 5.4% per 10 ppm of 10 B concentration in comparison with the neutron flux in the case of boron-free. It was also observed that the tissue dose at the center of the head phantom is depressed by approximately 4.7% per 10 ppm of the 10 B concentration and the tumor dose by approximately 5.3% per 10 ppm. According to depth of tumors, it was observed that the depressions of the doses in the tumors are ranged in 3.7 ∼ 9.2%. The dose calculations in the case of boron-free show that it is overestimated in comparison with the dose calculations in the cases of the inclusion of 10 B concentrations for the normal tissue and the tumors. Therefore, in dose calculation for BNCT, the depressions of neutron flux and dose should be considered. The results in this study are available to setting up the depression ratios which can be used for converting neutron and gamma fluxes and doses in phantom with boron free into the fluxes and doses in phantom with inclusion of 10 B concentrations in treatment. It is expected that the depression ratios is practicable to dose evaluation for BNCT

  3. Does increased Nitric Oxide production and oxidative stress due to high fat diet affect cardiac function after myocardial infarction?

    Directory of Open Access Journals (Sweden)

    Marjan Aghajani

    2017-01-01

    Full Text Available Background &Objectives: High fat (HF diet by affecting the oxidative stress and nitric oxide (NO production may lead to different effects on function of the heart after myocardial infarction (MI. In the present study we aimed to address the hypothesis that high release of NO by activated macrophages affects LV function after MI.Methods: The animals were randomly divided into four groups comprising each of 10 rats: 1 Sham; 2 MI; 3 Sham+ HF diet; 4 MI+ HF diet. Animals fed with HF diet 30 days before sham and MI surgery. MI was induced by permanent ligation of left anterior descending coronary artery (LAD. Nitric oxide (NO production of peritoneal macrophages, the concentrations of MDA in the heart and the infarct size were measured.Results: Our study indicated that HF has adverse effects on myocardium and it may increase NO production as well as oxidative stress, resulting in augmentation of infarct size.Conclusion: Our results add to our knowledge that HF diet was associated with overproduction of NO by peritoneal macrophages and ROS that lead to development of infarct size and adverse remodeling.

  4. Tolerance of spermatogonia to oxidative stress is due to high levels of Zn and Cu/Zn superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Fritzie T Celino

    Full Text Available BACKGROUND: Spermatogonia are highly tolerant to reactive oxygen species (ROS attack while advanced-stage germ cells such as spermatozoa are much more susceptible, but the precise reason for this variation in ROS tolerance remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using the Japanese eel testicular culture system that enables a complete spermatogenesis in vitro, we report that advanced-stage germ cells undergo intense apoptosis and exhibit strong signal for 8-hydroxy-2'-deoxyguanosine, an oxidative DNA damage marker, upon exposure to hypoxanthine-generated ROS while spermatogonia remain unaltered. Activity assay of antioxidant enzyme, superoxide dismutase (SOD and Western blot analysis using an anti-Copper/Zinc (Cu/Zn SOD antibody showed a high SOD activity and Cu/Zn SOD protein concentration during early spermatogenesis. Immunohistochemistry showed a strong expression for Cu/Zn SOD in spermatogonia but weak expression in advanced-stage germ cells. Zn deficiency reduced activity of the recombinant eel Cu/Zn SOD protein. Cu/Zn SOD siRNA decreased Cu/Zn SOD expression in spermatogonia and led to increased oxidative damage. CONCLUSIONS/SIGNIFICANCE: These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.

  5. Effects of Salinity Stress on Gas Exchange, Growth, and Nutrient Concentrations of Two Citrus Rootstocks

    Directory of Open Access Journals (Sweden)

    D. Khoshbakht

    2015-03-01

    Full Text Available A greenhouse study was undertaken to assess the salt tolerance of two citrus rootstocks, namely, Bakraii (Citrus sp. and Trifoliate orange (Poncirus trifoliata. A factorial experiment through a completely randomized design (CRD with three replications and four levels of salt including 0, 20, 40 and 60 mM NaCl was conducted. After eight weeks of treatment, number of leaves, plant height, leaf area, wet and dry weight of leaf, stem and root, length of root, chlorophyll content, net CO2 assimilation rate (ACO2, stomatal conductance (gs, transpiration (E and water use efficiency (WUE and ion concentrations were measured. Salinity decreased growth and net gas exchange. Trifoliate orange showed the most decrease in growth indices and net gas exchange compared with Bakraii. The ability to limit the transfer of sodium to leaves in low levels of salt was observed in Trifoliate orange, but this ability was not observed in high levels of salt. Results showed that accumulation of chloride in leaves and roots were less in Bakraii compared to the Trifoliate orange. The lower Cl- concentration in leaves of Bakraii than trifoliate orange suggests that the salinity tolerance of Bakraii is associated with less transport of Cl- to the leaves. Salinity increased K+ and decreased Mg2+ and Ca2+ concentrations in leaves of both rootstocks. It is proposed that salt stress effect on plant physiological processes such as changes in plant growth, Cl- and Na+ toxicity, and mineral distribution, decreases chlorophyll content and reduces the photosynthetic efficiency of these citrus species.

  6. Real-time prediction of extreme ambient carbon monoxide concentrations due to vehicular exhaust emissions using univariate linear stochastic models

    International Nuclear Information System (INIS)

    Sharma, P.; Khare, M.

    2000-01-01

    Historical data of the time-series of carbon monoxide (CO) concentration was analysed using Box-Jenkins modelling approach. Univariate Linear Stochastic Models (ULSMs) were developed to examine the degree of prediction possible for situations where only a limited data set, restricted only to the past record of pollutant data are available. The developed models can be used to provide short-term, real-time forecast of extreme CO concentrations for an Air Quality Control Region (AQCR), comprising a major traffic intersection in a Central Business District of Delhi City, India. (author)

  7. Chronic stress enhances synaptic plasticity due to disinhibition in the anterior cingulate cortex and induces hyper-locomotion in mice.

    Science.gov (United States)

    Ito, Hiroshi; Nagano, Masatoshi; Suzuki, Hidenori; Murakoshi, Takayuki

    2010-01-01

    The anterior cingulate cortex (ACC) is involved in the pathophysiology of a variety of mental disorders, many of which are exacerbated by stress. There are few studies, however, of stress-induced modification of synaptic function in the ACC that is relevant to emotional behavior. We investigated the effects of chronic restraint stress (CRS) on behavior and synaptic function in layers II/III of the ACC in mice. The duration of field excitatory postsynaptic potentials (fEPSPs) was longer in CRS mice than in control mice. The frequency of miniature inhibitory postsynaptic currents (mIPSCs) recorded by whole-cell patch-clamping was reduced in CRS mice, while miniature excitatory postsynaptic currents (mEPSCs) remained unchanged. Paired-pulse ratios (PPRs) of the fEPSP and evoked EPSC were larger in CRS. There was no difference in NMDA component of evoked EPSCs between the groups. Both long-term potentiation (LTP) and long-term depression of fEPSP were larger in CRS mice than in control mice. The differences between the groups in fEPSP duration, PPRs and LTP level were not observed when the GABA(A) receptor was blocked by bicuculline. Compared to control mice, CRS mice exhibited hyper-locomotive activity in an open field test, while no difference was observed between the groups in anxiety-like behavior in a light/dark choice test. CRS mice displayed decreased freezing behavior in fear conditioning tests compared to control mice. These findings suggest that CRS facilitates synaptic plasticity in the ACC via increased excitability due to disinhibition of GABA(A) receptor signalling, which may underlie induction of behavioral hyper-locomotive activity after CRS. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. Finite Element Modeling of Perturbation Fields due to Colonies of Stress Corrosion Cracks(SCCs) in a Gas Transmission Pipeline

    International Nuclear Information System (INIS)

    Yang, Sun Ho

    2001-01-01

    The detection of axial cracks using conventional MFL pig is a significant challenge in the gas pipeline inspection. In this study, a technique using interaction of circumferentially induced torrents with axial stress corrosion crack is presented. The feasibility of this technique is investigated using finite element modeling. Finite element analysis of such interaction is a difficult problem in terms of both computation time and memory requirements. The challenges arise due to the nonlinearity of material properties, the small sire of tight cracks relative to that of the magnetizer, and also time stepping involved in modeling velocity effects. This paper presents an approach based on perturbation methods. The overall analysis procedure is divided into 4 simple steps that can be performed sequentially. Modeling results show that this technique can effectively detect colonies of SCC as well as single SCC

  9. An assessment method of dose equivalent due to indoor 220Rn progeny by using 220Rn concentration measured at a 20 cm distance from wall

    International Nuclear Information System (INIS)

    Iida, T.; Ikebe, Y.; Okamoto, K.; Guo, Q.; Yamasaki, T.

    1996-01-01

    A pair of passive cup monitors with a different air exchange openings was developed for measuring simultaneously 222 Rn and 220 Rn concentrations. Indoor 220 Rn concentrations were very high in traditional Japanese dwellings with soil walls. The 220 Rn concentration decreases exponentially with the distance from wall. The effective diffusion coefficient of 220 Rn in dwelling and the exhalation rate of 220 Rn from wall were evaluated from the distribution of the 220 Rn concentrations. Then, indoor 220 Rn progeny concentration could be estimated from the 220 Rn concentration at a 20 cm distance from wall. From the results of the surveys. the average annual effective dose equivalent due to 220 Rn progeny was expected to be 0.67 mSv/year in the traditional Japanese dwellings. (author)

  10. Impacts of simulated drought stress and artificial damage on concentrations of flavonoids in Jatropha curcas (L.), a biofuel shrub.

    Science.gov (United States)

    Lama, Ang Dawa; Kim, Jorma; Martiskainen, Olli; Klemola, Tero; Salminen, Juha-Pekka; Tyystjärvi, Esa; Niemelä, Pekka; Vuorisalo, Timo

    2016-11-01

    We studied the possible roles of flavonoids in the antioxidant and antiherbivore chemistry in Jatropha curcas (L.), a Latin American shrub that holds great potential as a source of biofuel. Changes in flavonoid concentrations in the leaves of J. curcas seedlings exposed to artificial damage and to different rainfall patterns were assessed by applying a 3 2 -factorial experiment in a greenhouse. The concentrations of different flavonoids in the leaves of seedlings were significantly affected by interaction effects of artificial damage, drought stress and age of the seedling. The highest flavonoid concentrations were obtained in seedlings imposed to the highest percentage of artificial damage (50 %) and grown under extreme drought stress (200 mm year -1 ). In this treatment combination, flavonoid concentrations were three-fold as compared to seedlings exposed to the same level of artificial damage but grown in 1900 mm year -1 rainfall application. Without artificial damage, the concentration of flavonoids in the seedlings grown in 200 mm year -1 rainfall application was still two-fold compared to seedlings grown in higher (>800 mm year -1 ) rainfall applications. Thus, the observed flavonoid concentration patterns in the leaves of J. curcas seedlings were primarily triggered by drought stress and light rather than by artificial damage, suggesting that drought causes oxidative stress in J. curcas.

  11. Incorporation of the stress concentration slots into the flexures for a high-performance microaccelerometer

    International Nuclear Information System (INIS)

    Zhao Yulong; Sun Lu; Liu Yan; Wang Weizhong; Tian Bian

    2012-01-01

    Presented in this paper is a development of a high-performance piezoresistive microaccelerometer based on the slot etching in the quad flexures for the vibration detection of high speed spindle. The proposed structure consists of a proof mass supported by four thin flexures with slots etched in the middle. Boron diffused piezoresistors located near the stress concentration regions are used for sensing the localized stress resulting from the incorporation of the slots into the flexures. Theoretical analysis and finite element analysis show satisfactory results of an improved sensitivity and favorable natural frequency higher than 10 kHz, conforming to the initial design requirements. The microfabrication techniques are described to prototype the two accelerometer chips, one with slots and the other one without slots. The tested microaccelerometers with 3 V DC power supply show an average sensitivity of 0.424 mV/g normal to the proof mass plane, increased by 60.6% than the ones without slots. An average transverse sensitivity is found to be 9.2 μV/g along X axis and 14.2 μV/g along Y axis, either of which is less than 3.5% of prime-axis sensitivity. Concerning the resonant frequency, dynamic experiment shows about 12.46 kHz and is available for the proposed design with a tiny loss of 3.5% compared with the quad-beam design. When taking the product of sensitivity and natural frequency as judgment criteria, an inspiring increase by 28.6% of the figure of merit is accomplished for the proposed accelerometer. Overall, the findings of this study confirm the feasibility of incorporating slots into the conventional configurations to improve the sensor sensitivity while maintaining a comparatively high natural frequency.

  12. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    KAUST Repository

    Sullivan, J. M.; Paterson, C.; Wilson, S. K.; Duffy, B. R.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due

  13. Changes in polyphenol and sugar concentrations in wild type and genetically modified Nicotiana langsdorffii Weinmann in response to water and heat stress.

    Science.gov (United States)

    Ancillotti, Claudia; Bogani, Patrizia; Biricolti, Stefano; Calistri, Elisa; Checchini, Leonardo; Ciofi, Lorenzo; Gonnelli, Cristina; Del Bubba, Massimo

    2015-12-01

    In this study wild type Nicotiana langsdorffii plants were genetically transformed by the insertion of the rat gene (gr) encoding the glucocorticoid receptor or the rolC gene and exposed to water and heat stress. Water stress was induced for 15 days by adding 20% PEG 6000 in the growth medium, whereas the heat treatment was performed at 50 °C for 2 h, after that a re-growing capability study was carried out. The plant response to stress was investigated by determining electrolyte leakage, dry weight biomass production and water content. These data were evaluated in relation to antiradical activity and concentrations of total polyphenols, selected phenolic compounds and some soluble sugars, as biochemical indicators of metabolic changes due to gene insertion and/or stress treatments. As regards the water stress, the measured physiological parameters evidenced an increasing stress level in the order rolC < gr < WT plants (e.g. about 100% and 50% electrolyte leakage increase in WT and gr samples, respectively) and complied with the biochemical pattern, which consisted in a general decrease of antiradical activity and phenolics, together with an increase in sugars. As regard heat stress, electrolyte leakage data were only in partial agreement with the re-growing capability study. In fact, according to this latter evaluation, gr was the genotype less affected by the heat shock. In this regard, sugars and especially phenolic compounds are informative of the long-term effects due to heat shock treatment. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Increased serum C-reactive protein concentrations in dogs with congestive heart failure due to myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Reimann, M. J.; Ljungvall, I.; Hillstrom, A.

    2016-01-01

    Cardiovascular disease in humans and dogs is associated with mildly increased circulating concentrations of C-reactive protein (CRP). Few studies have evaluated associations between circulating CRP and canine myxomatous mitral valve disease (MMVD) and the results reported have been divergent....... The aim of this study was to investigate whether serum concentrations of CRP, determined using a novel automated canine-specific high -sensitivity CRP assay (Gentian hsCRP), were associated with severity of MMVD and selected clinical variables in dogs. The study included 188 client-owned dogs...... with different severities of MMVD. Dogs were classified based on ACVIM consensus statement guidelines (group A, n = 58; group BI, n = 56; group B2, n = 38; group C, n = 36). Data were analysed using descriptive statistics and multiple regression analysis. Dogs with congestive heart failure (CHF; group C) had...

  15. Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions

    Directory of Open Access Journals (Sweden)

    S. Eckhardt

    2007-08-01

    Full Text Available Soils and forests in the boreal region of the Northern Hemisphere are recognised as having a large capacity for storing air-borne Persistent Organic Pollutants (POPs, such as the polychlorinated biphenyls (PCBs. Following reductions of primary emissions of various legacy POPs, there is an increasing interest and debate about the relative importance of secondary re-emissions on the atmospheric levels of POPs. In spring of 2006, biomass burning emissions from agricultural fires in Eastern Europe were transported to the Zeppelin station on Svalbard, where record-high levels of many air pollutants were recorded (Stohl et al., 2007. Here we report on the extremely high concentrations of PCBs that were also measured during this period. 21 out of 32 PCB congeners were enhanced by more than two standard deviations above the long-term mean concentrations. In July 2004, about 5.8 million hectare of boreal forest burned in North America, emitting a pollution plume which reached the Zeppelin station after a travel time of 3–4 weeks (Stohl et al., 2006. Again, 12 PCB congeners were elevated above the long-term mean by more than two standard deviations, with the less chlorinated congeners being most strongly affected. We propose that these abnormally high concentrations were caused by biomass burning emissions. Based on enhancement ratios with carbon monoxide and known emissions factors for this species, we estimate that 130 and 66 μg PCBs were released per kilogram dry matter burned, respectively. To our knowledge, this is the first study relating atmospheric PCB enhancements with biomass burning. The strong effects on observed concentrations far away from the sources, suggest that biomass burning is an important source of PCBs for the atmosphere.

  16. Stress in telephone helpline nurses is associated with failures of concentration, attention and memory, and with more conservative referral decisions.

    Science.gov (United States)

    Allan, Julia L; Farquharson, Barbara; Johnston, Derek W; Jones, Martyn C; Choudhary, Carolyn J; Johnston, Marie

    2014-05-01

    Nurses working for telephone-based medical helplines must maintain attentional focus while quickly and accurately processing information given by callers to make safe and appropriate treatment decisions. In this study, both higher levels of general occupational stress and elevated stress levels on particular shifts were associated with more frequent failures of attention, memory, and concentration in telephone nurses. Exposure to a stressful shift was also associated with a measurable increase in objectively assessed information-processing errors. Nurses who experienced more frequent cognitive failures at work made more conservative decisions, tending to refer patients on to other health professionals more often than other nurses. As stress is associated with cognitive performance decrements in telephone nursing, stress-reduction interventions could improve the quality and safety of care that callers to medical helplines receive. © 2013 The British Psychological Society.

  17. Subinhibitory concentrations of antibiotics affect stress and virulence gene expression in Listeria monocytogenes and cause enhanced stress sensitivity but do not affect Caco‐2 cell invasion

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Holch, Anne; Gram, Lone

    2012-01-01

    with promoter fusions, 14 of 16 antibiotics induced or repressed expression of one or more stress and/or virulence genes. Despite ampicillin‐induced up‐regulation of PinlA‐lacZ expression, Caco‐2 cell invasion was not affected. Subinhibitory concentrations of ampicillin and tetracycline caused up‐ and down...

  18. Inhalation dose due to indoor radon and thoron concentrations in the surrounding villages of Hyderabad, Andhra Pradesh, India

    International Nuclear Information System (INIS)

    Sreenath Reddy, M.; Sreenivasa Reddy, B.; Yadagiri Reddy, P.; Gopal Reddy, Ch.; Rama Reddy, K.

    2006-01-01

    Inhalation of radon, thoron and their decay products is the major contribution to the total radioactive dose received by the human population from the natural radiation. The indoor inhalation doses due to radon, thoron and their progenies in the surrounding villages of Hyderabad, India are evaluated. The average inhalation dose due to radon and its progeny is found to be 0.26 ± 0.21 mSv y -1 and due to thoron and its progeny is 0.35 ± 0.38 mSv y -1 . The inhalation dose is also analyzed based on the types of floor, roof and walls of the dwellings and it is found that the dwellings with mud type construction materials have higher inhalation dose. Generally, the contribution of thoron and its progeny to the total dose is neglected but in the present study area the fractional dose of thoron and its progeny is found to be comparable to that of radon and its progeny. (author)

  19. Estimative of alpha radiation dose due to natural concentration of Ra-226 in waters from Pocos de Caldas

    International Nuclear Information System (INIS)

    Sigaud, G.M.

    1979-01-01

    A dosimetric model for calculating the annual dose equivalent for an individual and the annual collective dose equivalent from 226 Ra is developed. This model is applied to the measured concentrations of 226 Ra in waters of the hydro graphic basins of the Pocos de Caldas plateau, using the pathways of drinking water and ingestion of food grown in irrigated fields. A linear model for simulating potential 226 Ra contamination of the waters of the region is also applied, and the doses from these contaminations are estimated using the dosimetric model developed. (author)

  20. Stress State Analysis and Failure Mechanisms of Masonry Columns Reinforced with FRP under Concentric Compressive Load

    Directory of Open Access Journals (Sweden)

    Jiří Witzany

    2016-04-01

    Full Text Available The strengthening and stabilization of damaged compressed masonry columns with composites based on fabrics of high-strength fibers and epoxy resin, or polymer-modified cement mixtures, belongs to novel, partially non-invasive and reversible progressive methods. The stabilizing and reinforcing effect of these fabrics significantly applies to masonry structures under concentric compressive loading whose failure mechanism is characterized by the appearance and development of vertical tensile cracks accompanied by an increase in horizontal masonry strain. During the appearance of micro and hairline cracks (10−3 to 10−1 mm, the effect of non-pre-stressed wrapping composite is very small. The favorable effect of passive wrapping is only intensively manifested after the appearance of cracks (10−1 mm and bigger at higher loading levels. In the case of “optimum” reinforcement of a masonry column, the experimental research showed an increase in vertical displacements δy (up to 247%, horizontal displacements δx (up to 742% and ultimate load-bearing capacity (up to 136% compared to the values reached in unreinforced masonry columns. In the case of masonry structures in which no intensive “bed joint filler–masonry unit” interaction occurs, e.g., in regular coursed masonry with little differences in the mechanical characteristics of masonry units and the binder, the reinforcing effect of the fabric applies only partially.

  1. Mapping concentrations of posttraumatic stress and depression trajectories following Hurricane Ike.

    Science.gov (United States)

    Gruebner, Oliver; Lowe, Sarah R; Tracy, Melissa; Joshi, Spruha; Cerdá, Magdalena; Norris, Fran H; Subramanian, S V; Galea, Sandro

    2016-08-25

    We investigated geographic concentration in elevated risk for a range of postdisaster trajectories of chronic posttraumatic stress symptom (PTSS) and depression symptoms in a longitudinal study (N = 561) of a Hurricane Ike affected population in Galveston and Chambers counties, TX. Using an unadjusted spatial scan statistic, we detected clusters of elevated risk of PTSS trajectories, but not depression trajectories, on Galveston Island. We then tested for predictors of membership in each trajectory of PTSS and depression (e.g., demographic variables, trauma exposure, social support), not taking the geographic nature of the data into account. After adjusting for significant predictors in the spatial scan statistic, we noted that spatial clusters of PTSS persisted and additional clusters of depression trajectories emerged. This is the first study to show that longitudinal trajectories of postdisaster mental health problems may vary depending on the geographic location and the individual- and community-level factors present at these locations. Such knowledge is crucial to identifying vulnerable regions and populations within them, to provide guidance for early responders, and to mitigate mental health consequences through early detection of mental health needs in the population. As human-made disasters increase, our approach may be useful also in other regions in comparable settings worldwide.

  2. Whey protein concentrate supplementation protects rat brain against aging-induced oxidative stress and neurodegeneration.

    Science.gov (United States)

    Garg, Geetika; Singh, Sandeep; Singh, Abhishek Kumar; Rizvi, Syed Ibrahim

    2018-05-01

    Whey protein concentrate (WPC) is a rich source of sulfur-containing amino acids and is consumed as a functional food, incorporating a wide range of nutritional attributes. The purpose of this study is to evaluate the neuroprotective effect of WPC on rat brain during aging. Young (4 months) and old (24 months) male Wistar rats were supplemented with WPC (300 mg/kg body weight) for 28 days. Biomarkers of oxidative stress and antioxidant capacity in terms of ferric reducing antioxidant potential (FRAP), lipid hydroperoxide (LHP), total thiol (T-SH), protein carbonyl (PC), reactive oxygen species (ROS), nitric oxide (NO), and acetylcholinesterase (AChE) activity were measured in brain of control and experimental (WPC supplemented) groups. In addition, gene expression and histopathological studies were also performed. The results indicate that WPC augmented the level of FRAP, T-SH, and AChE in old rats as compared with the old control. Furthermore, WPC-treated groups exhibited significant reduction in LHP, PC, ROS, and NO levels in aged rats. WPC supplementation also downregulated the expression of inflammatory markers (tumor necrosis factor alpha, interleukin (IL)-1β, IL-6), and upregulated the expression of marker genes associated with autophagy (Atg3, Beclin-1, LC3B) and neurodegeneration (neuron specific enolase, Synapsin-I, MBP-2). The findings suggested WPC to be a potential functional nutritional food supplement that prevents the progression of age-related oxidative damage in Wistar rats.

  3. SOIL N, P AND K CONCENTRATIONS AND RICE YIELD INCREASED DUE TO THE APPLICATION OF Azolla pinnata

    Directory of Open Access Journals (Sweden)

    A. Arivin Rivaie*

    2014-01-01

    Full Text Available Many studies showed that application of Azolla pinnata as biofertilizer improved soil fertility some agricultural crops, including rice, whereas farmers in Lampung consider that A. pinnata suppresses growth of rice seedlings, so they throw it field by raising irrigation water surface. Information on effects A. pinnata application on changes in nutrient availability and rice yield obtained from paddy fields of regions still rare. A study was carried out to investigate effects of different rates of A. pinnata on changes in N, P, K concentrations in paddy soils, N uptake, and rice yield. A well-irrigated paddy field was incorporated with A. pinnata, and then rice seedlings of Ciherang variety had been grown from June up to December 2009. Results: application of A. pinnata at dose of five t per ha increased concentration of N, P and K as well as rice yield. A. pinnata had a relatively high N content, ie 2.43 percent. Application of A. pinnata of 7.5 t per ha increased significantly available soil P, indicated that A. pinnata requires a fairly high P to grow optimally. Application of A. pinnata of 7.5 t per ha gave highest dry grain yield, suggests that application A. pinnata did not suppress rice yield, even use of A. pinnata as organic matter source will help to conserve fossil fuels and foreign exchange as well as will allow more paddy fields that can be fertilized by N.

  4. Evaluation of creep damage due to stress relaxation in SA533 grade B class 1 and SA508 class 3 pressure vessel steels

    International Nuclear Information System (INIS)

    Hoffmann, C.L.; Urko, W.

    1993-01-01

    Creep damage can result from stress relaxation of residual stresses in components when exposed to high temperature thermal cycles. Pressure vessels, such as the reactor vessel of the modular high-temperature gas reactor (MHTGR), which normally operate at temperatures well below the creep range can develop relatively high residual stresses in high stress locations. During short term excursions to elevated-temperatures, creep damage can be produced by the loadings on the vessel. In addition, residual stresses will relax out, causing greater creep damage in the pressure vessel material than might otherwise be calculated. The evaluation described in this paper assesses the magnitude of the creep damage due to relaxation of residual stresses resulting from short term exposure of the pressure vessel material to temperatures in the creep range. Creep relaxation curves were generated for SA533 Grade B, Class 1 and SA508 Class 3 pressure vessel steels using finite element analysis of a simple uniaxial truss loaded under constant strain conditions to produce an initial axial stress equal to 1.25 times the material yield strength at temperature. The strain is held constant for 1000 hours at prescribed temperatures from 700 F to 1000 F. The material creep law is used to calculate the relaxed stress for each time increment. The calculated stress relaxation versus time curves are compared with stress relaxation test data. Creep damage fractions are calculated by integrating the stress relaxation versus time curves and performing a linear creep damage summation using the minimum stress to rupture curves at the respective relaxation temperatures. Cumulative creep damage due to stress relaxation as a function of time and temperature is derived from the linear damage summation

  5. Prediction of residual stresses and distortions due to laser beam welding of butt joints in pressure vessels

    International Nuclear Information System (INIS)

    Moraitis, G.A.; Labeas, G.N.

    2009-01-01

    A two-level three-dimensional Finite Element (FE) model has been developed to predict keyhole formation and thermo-mechanical response during Laser Beam Welding (LBW) of steel and aluminium pressure vessel or pipe butt-joints. A very detailed and localized (level-1) non-linear three-dimensional transient thermal model is initially developed, which simulates the mechanisms of keyhole formation, calculates the temperature distribution in the local weld area and predicts the keyhole size and shape. Subsequently, using a laser beam heat source model based on keyhole assumptions, a global (level-2) thermo-mechanical analysis of the LBW butt-joint is performed, from which the joint residual stresses and distortions are calculated. All the major physical phenomena associated to LBW, such as laser heat input via radiation, heat losses through convection and radiation, as well as latent heat are accounted for in the numerical model. Material properties and particularly enthalpy, which is very important due to significant material phase changes, are introduced as temperature-dependent functions. The main advantages of the developed model are its efficiency, flexibility and applicability to a wide range of LBW problems (e.g. welding for pressure vessel or pipework construction, welding of automotive, marine or aircraft components, etc). The model efficiency arises from the two-scale approach applied. Minimal or no experimental data are required for the keyhole size and shape computation by the level-1 model, while the thermo-mechanical response calculation by the level-2 model requires only process and material data. Therefore, it becomes possible to efficiently apply the developed simulation model to different material types and varying welding parameters (i.e. welding speed, heat source power, joint geometry, etc.) in order to control residual stresses and distortions within the welded structure

  6. Oxidative stress biomarkers and their relationship with cytokine concentrations in overweight/obese pregnant women and their neonates.

    Science.gov (United States)

    Hernández-Trejo, María; Montoya-Estrada, Araceli; Torres-Ramos, Yessica; Espejel-Núñez, Aurora; Guzmán-Grenfell, Alberto; Morales-Hernández, Rosa; Tolentino-Dolores, Maricruz; Laresgoiti-Servitje, Estibalitz

    2017-01-07

    Oxidative damage present in obese/overweight mothers may lead to further oxidative stress conditions or inflammation in maternal and cord blood samples. Thirty-four pregnant women/newborn pairs were included in this study to assess the presence of oxidative stress biomarkers and their relationship with serum cytokine concentrations. Oxidative stress biomarkers and antioxidant enzymes were compared between the mother/offspring pairs. The presence of 27 cytokines was measured in maternal and cord blood samples. Analyses were initially performed between all mothers and newborns and later between normal weight and mothers with overweight and obesity, and diabetic/non-diabetic women. Significant differences were found in biomarker concentrations between mothers and newborns. Additionally, superoxide-dismutase activity was higher in pre-pregnancy overweight mothers compared to those with normal weight. Activity for this enzyme was higher in neonates born from mothers with normal pregestational weight compared with their mothers. Nitrites in overweight/obese mothers were statistically lower than in their offspring. Maternal free fatty acids, nitrites, carbonylated proteins, malondialdehyde and superoxide dismutase predicted maternal serum concentrations of IL-4, IL-13, IP-10 and MIP-1β. Arginase activity in maternal plasma was related to decreased concentrations of IL-4 and IL-1β in cord arterial blood. Increased maternal malondialdehyde plasma was associated with higher levels of IL-6 and IL-7 in the offspring. Oxidative stress biomarkers differ between mothers and offspring and can predict maternal and newborn cytokine concentrations, indicating a potential role for oxidative stress in foetal metabolic and immunologic programming. Moreover, maternal obesity and diabetes may affect maternal microenvironments, and oxidative stress related to these can have an impact on the placenta and foetal growth.

  7. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

    Directory of Open Access Journals (Sweden)

    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 μmol mol−1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  8. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

    Directory of Open Access Journals (Sweden)

    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 mol mol-1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  9. Honey bee (Apis mellifera) drones survive oxidative stress due to increased tolerance instead of avoidance or repair of oxidative damage

    Science.gov (United States)

    Oxidative stress can lead to premature aging symptoms and cause acute mortality at higher doses in a range of organisms. Oxidative stress resistance and longevity are mechanistically and phenotypically linked: considerable variation in oxidative stress resistance exists among and within species and ...

  10. Water concentration/activity and loss of vitamins B1 and E in pork due to gamma radiation

    International Nuclear Information System (INIS)

    Fox, J.B. Jr.; Lakritz, L.; Kohout, K.M.; Thayer, D.W.

    1994-01-01

    When irradiated, increasing the water content of pork by partial rehydration of freeze-dried L. dorsi muscle resulted in increasing rate of thiamin loss from zero in dry tissue to ca 6%/kGy of irradiation in tissue with 70% water. Conversely, the rate of loss of alpha-tocopherol decreased from 44%/kGy at 0% to 32%/kGy at 70% water. Decreasing water activity in buffers or in ground or freeze-dried pork by salt or sucrose had no effect on rate of loss of either vitamin following irradiation. Salt decreased the loss of both vitamins in pork due to competition for the hydroxyl radical by chloride ions

  11. Stress concentration factors for integral and pad reinforced nozzles in spherical pressure vessels subjected to radial load and moment

    International Nuclear Information System (INIS)

    Soliman, S.F.; Gill, S.S.

    1979-01-01

    Charts are presented giving the elastic stress concentration factors in spherical pressure vessels with pad and integral reinforcement for radial branches subjected to radial load and moment. The effect of all the geometrical parameters is discussed, including the limitations of thin shell theory on the validity of the results. (author)

  12. The influence of discontinuity and orthotropy of fracture toughness on conditions of fracture initiation in singular stress concentrators

    Czech Academy of Sciences Publication Activity Database

    Klusák, Jan; Profant, T.; Knésl, Zdeněk; Kotoul, M.

    2013-01-01

    Roč. 110, SEP (2013), s. 438-447 ISSN 0013-7944 R&D Projects: GA ČR GAP108/10/2049 Institutional support: RVO:68081723 Keywords : Stability criterion of notch es * crack initiation * Singular stress concentrators * bi-material notch Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.662, year: 2013

  13. Modelling and simulation of temperature and concentration dispersion in a couple stress nanofluid flow through stenotic tapered arteries

    Science.gov (United States)

    Ramana Reddy, J. V.; Srikanth, D.; Das, Samir K.

    2017-08-01

    A couple stress fluid model with the suspension of silver nanoparticles is proposed in order to investigate theoretically the natural convection of temperature and concentration. In particular, the flow is considered in an artery with an obstruction wherein the rheology of blood is taken as a couple stress fluid. The effects of the permeability of the stenosis and the treatment procedure involving a catheter are also considered in the model. The obtained non-linear momentum, temperature and concentration equations are solved using the homotopy perturbation method. Nanoparticles and the two viscosities of the couple stress fluid seem to play a significant role in the flow regime. The pressure drop, flow rate, resistance to the fluid flow and shear stress are computed and their effects are analyzed with respect to various fluids and geometric parameters. Convergence of the temperature and its dependency on the degree of deformation is effectively depicted. It is observed that the Nusselt number increases as the volume fraction increases. Hence magnification of molecular thermal dispersion can be achieved by increasing the nanoparticle concentration. It is also observed that concentration dispersion is greater for severe stenosis and it is maximum at the first extrema. The secondary flow of the axial velocity in the stenotic region is observed and is asymmetric in the tapered artery. The obtained results can be utilized in understanding the increase in heat transfer and enhancement of mass dispersion, which could be used for drug delivery in the treatment of stenotic conditions.

  14. Abiotic stress growth conditions induce different responses in kernel iron concentration across genotypically distinct maize inbred varieties

    Science.gov (United States)

    Kandianis, Catherine B.; Michenfelder, Abigail S.; Simmons, Susan J.; Grusak, Michael A.; Stapleton, Ann E.

    2013-01-01

    The improvement of grain nutrient profiles for essential minerals and vitamins through breeding strategies is a target important for agricultural regions where nutrient poor crops like maize contribute a large proportion of the daily caloric intake. Kernel iron concentration in maize exhibits a broad range. However, the magnitude of genotype by environment (GxE) effects on this trait reduces the efficacy and predictability of selection programs, particularly when challenged with abiotic stress such as water and nitrogen limitations. Selection has also been limited by an inverse correlation between kernel iron concentration and the yield component of kernel size in target environments. Using 25 maize inbred lines for which extensive genome sequence data is publicly available, we evaluated the response of kernel iron density and kernel mass to water and nitrogen limitation in a managed field stress experiment using a factorial design. To further understand GxE interactions we used partition analysis to characterize response of kernel iron and weight to abiotic stressors among all genotypes, and observed two patterns: one characterized by higher kernel iron concentrations in control over stress conditions, and another with higher kernel iron concentration under drought and combined stress conditions. Breeding efforts for this nutritional trait could exploit these complementary responses through combinations of favorable allelic variation from these already well-characterized genetic stocks. PMID:24363659

  15. Changes in guava (Psidium guajava L. var. Paluma nectar volatile compounds concentration due to thermal processing and storage

    Directory of Open Access Journals (Sweden)

    Maria Ivaneide Coutinho Correa

    2010-12-01

    Full Text Available Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC or refrigerated (5 ± 2 ºC under fluorescent light exposure and analyzed on the day after processing (time zero and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC -Mass Spectrometry (MS: hexanal, (E-hex-2-enal, 1-hexenol, (Z-hex-3-enol, (Z-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001 in hexanal and (Z-hex-3-enyl acetate (p = 0.0029. As for the storage time, there was a much greater decrease in the esters contents, such as (Z-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

  16. Impairment due to combined sleep restriction and alcohol is not mitigated by decaying breath alcohol concentration or rest breaks.

    Science.gov (United States)

    Manousakis, Jessica E; Anderson, Clare

    2017-09-01

    Epidemiological and laboratory-based driving simulator studies have shown the detrimental impact of moderate, legal levels of alcohol consumption on driving performance in sleepy drivers. As less is known about the time course of decaying alcohol alongside performance impairment, our study examined impairment and recovery of performance alongside decaying levels of alcohol, with and without sleep restriction. Sixteen healthy young males (18-27 years) underwent 4 counterbalanced conditions: Baseline, Alcohol (breath alcohol concentration [BrAC] batteries commenced 1 hr after consumption and were completed every 30 min for 2 hr (1:30 p.m.-3:30 p.m.). The Combined condition impaired subjective and objective sleepiness. Here, performance deficits peaked 90 min after alcohol consumption or 30 min after the BrAC peak. Performance did not return to baseline levels until 2.5 hr following consumption, despite receiving rest breaks in between testing. These findings suggest that (a) falling BrACs are an inadequate guide for performance/safety and (b) rest breaks without sleep are not a safety measure for mitigating performance impairment when consuming alcohol following restricted sleep. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Everyday hassles and uplifts among women on long-term sick-leave due to stress-related disorders.

    Science.gov (United States)

    Johansson, Gun; Eklund, Mona; Erlandsson, Lena-Karin

    2012-05-01

    A balance between different experiences of occupations in everyday life is important for well-being. The study aim was to describe hassles and uplifts in everyday occupations among women on long-term sick-leave due to stress-related disorders. The sample consisted of 77 women and experiences were collected by the THU-5 instrument. The statements were analysed using quantitative content analysis. Data were categorized into three domains of hassles concerning oneself, doings, and social and physical context. The same domains occurred among the uplifts. Hassles were mostly generated by disturbing people around the women and by their limited body functions. The women were uplifted by supportive social relationships and by performing relaxing and calming occupations. The study illuminates the strong need for social support among women on sick-leave, as well as their low level of energy, which was an obvious obstacle for performing occupations. It is suggested that, in order to increase well-being in the target group, the occupational therapist should meet their need for occupations that match their current level of energy. The challenge for the client is to avoid remaining in a pattern of low-demand occupations without exceeding her/his capacity and returning to an unhealthy pattern of occupations.

  18. THE COMBINED EFFECTS OF STRESS CONCENTRATION AND TENSILE STRESSES FROM AUTOFRETTAGE ON THE LIFE OF PRESSURE VESSELS

    Science.gov (United States)

    2017-02-22

    information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing ... hydraulically or mechanically overstrained in order to impart favorable near bore residual compressive hoop stresses in an attempt to enhance fatigue life. As a...detrimental. In the early stages of development of each system, multiple full size vessels are hydraulically fatigue tested and a safe life is

  19. Prenatal Transportation Stress Alters Temperament and Serum Cortisol Concentrations in Suckling Brahman Calves

    Science.gov (United States)

    This experiment examined the relationship between prenatal stress and subsequent calf temperament through weaning. The prenatal stressor utilized was repeated transportation of pregnant Brahman cows for 2 hours at 60, 80, 100, 120, and 140 days of gestation. Prenatally stressed calves (n = 41) were ...

  20. Is gill cortisol concentration a good acute stress indicator in fish? A study in rainbow trout and zebrafish

    DEFF Research Database (Denmark)

    Gesto, Manuel; Hernandez, Juan; Lopez-Patino, Marcos A.

    2015-01-01

    Cortisol is the main biomarker of physiological stress in fish. It is usually measured in plasma, which requires blood collection. Though cortisol is produced in the anterior kidney, it can diffuse easily through cell membranes due to its lipophilic nature. Taking advantage of that, some non-inva...

  1. The secondary stress analyses in the fuel pin cladding due to the swelling gradient across the wall thickness

    International Nuclear Information System (INIS)

    Uwaba, Tomoyuki; Ukai, Shigeharu

    2002-01-01

    Irradiation deformation analyses of FBR fuel cladding were made by using the finite element method. In these analyses the history of the stress occurred in the cladding was evaluated paying attention to the secondary stress induced by the swelling difference across the wall thickness. It was revealed that the difference of the swelling incubation dose in the direction of the thickness and the irradiation creep deformation play an important role in the history of the secondary stress. The effect of the stress-enhanced swelling was also analyzed in this study

  2. Chronic stress alters concentrations of corticosterone receptors in a tissue-specific manner in wild house sparrows (Passer domesticus).

    Science.gov (United States)

    Lattin, Christine R; Romero, L Michael

    2014-07-15

    The physiological stress response results in release of glucocorticoid hormones such as corticosterone (CORT). Whereas short-term activation of this response helps animals cope with environmental stressors, chronic activation can result in negative effects including metabolic dysregulation and reproductive failure. However, there is no consensus hormonal profile of a chronically stressed animal, suggesting that researchers may need to look beyond hormone titers to interpret the impacts of chronic stress. In this study, we brought wild house sparrows (Passer domesticus) into captivity. We then compared glucocorticoid and mineralocorticoid receptor concentrations in sparrows exposed either to a standardized chronic stress protocol (n=26) or to standard husbandry conditions (controls; n=20). We used radioligand binding assays to quantify receptors in whole brain, liver, kidneys, spleen, gonads, gastrocnemius and pectoralis muscle, omental and subcutaneous fat, and bib and back skin. In most tissues, CORT receptors did not differ between controls and stressed animals, although we found marginal increases in receptor density in kidney and testes in stressed birds at some time points. Only in pectoralis muscle was there a robust effect of chronic stress, with both receptor types higher in stressed animals. Increased pectoralis sensitivity to CORT with chronic stress may be part of the underlying mechanism for muscle wasting in animals administered exogenous CORT. Furthermore, the change in pectoralis was not paralleled by gastrocnemius receptors. This difference may help explain previous reports of a greater effect of CORT on pectoralis than on other muscle types, and indicate that birds use this muscle as a protein reserve. © 2014. Published by The Company of Biologists Ltd.

  3. Stress Distribution in the Dissimilar Metal Butt Weld of Nuclear Reactor Piping due to the Simulation Technique for the Repair Welding

    International Nuclear Information System (INIS)

    Lee, Hweeseung; Huh, Namsu; Kim, Jinsu; Lee, Jinho

    2013-01-01

    During welding, the dissimilar metal butt welds of nuclear piping are typically subjected to repair welding in order to eliminate defects that are found during post-weld inspection. It has been found that the repair weld can significantly increase the tensile residual stress in the weldment, and therefore, accurate estimation of the weld residual stress due to repair weld, especially for dissimilar metal welds using Ni-based alloy 82/182 in nuclear components, is of great importance in order to assess susceptibility to primary water stress corrosion cracking. In the present study, the stress distributions of dissimilar metal butt welds in nuclear reactor piping subjected to repair weld were investigated based on detailed nonlinear finite element analyses. Particular emphasis was placed on the variation of the stress distribution in the dissimilar metal butt weld according to the finite element welding analysis sequence for the repair welding process

  4. Barotropic Eulerian residual circulation in the Gulf of California due to the M{sub 2} tide and wind stress

    Energy Technology Data Exchange (ETDEWEB)

    Argote, M. L.; Lavin, M. F.; Amador, A. [Departamento de Oceanografia Fisica, CICESE, Ensenada, Baja California (Mexico)

    1998-07-01

    A vertically integrated, non-linear numerical model in finite differences is used to analyze two forcing mechanisms of the mean barotropic circulation in the Gulf of California: topographic rectification due to tidal currents (M{sub 2}) and wind stress. Under tidal forcing the nonlinearities of the momentum equations induce unorganized strong tidal induced residual currents (u{sub e} > 5 cm s{sup -}1) in the channels between the islands, and along-isobath anticyclonic circulation in the Northern Gulf, with speeds u{sub 3} < 2.5 cm s{sup -}1 over the edge of Delfin Basin. These numerical results are in agreement with analytical results, which indicate that the tidal-induced currents are mostly due to the advective terms, and that continuity and the Coriolis term (but regulated by bottom friction) are responsible for the along-isobath flow. The quadratic bottom friction plays a role in generating mean currents only in the very shallow area off the Colorado River Delta. The effect of wind stress was modeled by imposing upon the running M{sub 2} model a constant surface stress ( r = 0.016 Pa), from the NW for winter conditions and from the SE for summer conditions. The wind-induced circulation was obtained by averaging over a tidal cycle and then subtracting the tidal residuals. The two wind directions produce almost identical circulation patterns, but with opposite directions. For the NW wind stress, the main features of the predicted circulation are: (a) In the Northern Gulf an anticyclonic circulation pattern, with the strongest currents (up to {approx} 10 cm s-1) following the bathymetry of the rim of Delfin Basin, Wagner Basin and the mainland coast off Bahia Adair and Bahia San Jorge. There is also a southward flow along the peninsula coast, from the Colorado River to Bahia San Luis Gonzaga. (b) In the Southern Gulf, there is a strong flow ({approx} 10 to 15 cm s{sup -}1) to the SE over the continental shelf along the mainland coast. A somewhat less well

  5. Leptin concentrations in response to acute stress predict subsequent intake of comfort foods

    Science.gov (United States)

    Tomiyama, A. Janet; Schamarek, Imke; Lustig, Robert H.; Kirschbaum, Clemens; Puterman, Eli; Havel, Peter J.; Epel, Elissa S.

    2012-01-01

    Both animals and humans show a tendency toward eating more “comfort food” (high fat, sweet food) after acute stress. Such stress eating may be contributing to the obesity epidemic, and it is important to understand the underlying psychobiological mechanisms. Prior investigations have studied what makes individuals eat more after stress; this study investigates what might make individuals eat less. Leptin has been shown to increase following a laboratory stressor, and is known to affect eating behavior. This study examined whether leptin reactivity accounts for individual differences in stress eating. To test this, we exposed forty women to standardized acute psychological laboratory stress (Trier Social Stress Test) while blood was sampled repeatedly for measurements of plasma leptin. We then measured food intake after the stressor in 29 of these women. Increasing leptin during the stressor predicted lower intake of comfort food. These initial findings suggest that acute changes in leptin may be one of the factors modulating down the consumption of comfort food following stress. PMID:22579988

  6. Post-traumatic stress disorder among asylum seekers and refugees in Istanbul may be predicted by torture and loss due to violence.

    Science.gov (United States)

    Tufan, Ali Evren; Alkin, Melis; Bosgelmez, Sukriye

    2013-06-01

    Turkey is both a source and target for asylum seekers seeking refugee status in countries of European Union. There is a scarcity of research on the mental health issues of asylum seekers and refugees residing in Turkey. This study aimed: 1) to provide clinical and demographic information on asylum seekers and refugees receiving mental health services from a non-governmental refugee support program in Istanbul between 2005 and 2007, and 2) to evaluate the differences between patients diagnosed with post-traumatic stress disorder (PTSD) with those who did not meet criteria. The study was conducted at the Mental Health Division of the Refugee Advocacy Support Group. Between July 2005 and February 2007, 1209 asylum seekers applied to the support group; 75 of these individuals (6.2%) were referred for psychiatric evaluation while 57 were diagnosed as having a psychopathology. The number of analyzed subjects was 57. PTSD and major depressive disorder were the most common diagnoses (55.2% for both). The most common criteria of PTSD reported were problems in concentration and social isolation (97.3% for both). Suffering torture and losing a significant other due to violence were found to be associated with a diagnosis of PTSD. This study is the first of its kind to be conducted on a mixed refugee population residing in Turkey and focusing on their mental health problems. Our results should be tested within larger samples of refugees residing in different cities of Turkey.

  7. Simulation of Stress Concentration Problems in Laminated Plates by Quasi-Trefftz Finite Element Models

    Directory of Open Access Journals (Sweden)

    Flávio Luiz de Silva Bussamra

    Full Text Available Abstract Hybrid quasi-Trefftz finite elements have been applied with success to the analysis of laminated plates. Two independent fields are approximated by linearly independent, hierarchical polynomials: the stress basis in the domain, adapted from Papkovitch-Neuber solution of Navier equations, and the displacement basis, defined on element surface. The stress field that satisfies the Trefftz constraint a priori for isotropic material is adapted for orthotropic materials, which leads to the term "quasi". In this work, the hexahedral hybrid quasi-Trefftz stress element is applied to the modeling of nonsymmetric laminates and laminated composite plates with geometric discontinuities. The hierarchical p-refinement is exploited.

  8. Improved tolerance to drought stress after anthesis due to priming before anthesis in wheat (Triticum aestivum L.) var. Vinjett

    DEFF Research Database (Denmark)

    Wang, Xiao; Vignjevic, Marija; Jiang, Dong

    2014-01-01

    Drought stress occurring during the reproductive growth stage leads to considerable reductions in crop production and has become an important limiting factor for food security globally. In order to explore the possible role of drought priming (pre-exposure of the plants to mild drought stress...

  9. Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease

    International Nuclear Information System (INIS)

    Oe, Shinji; Miyagawa, Koichiro; Honma, Yuichi; Harada, Masaru

    2016-01-01

    Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

  10. Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease

    Energy Technology Data Exchange (ETDEWEB)

    Oe, Shinji, E-mail: ooes@med.uoeh-u.ac.jp; Miyagawa, Koichiro, E-mail: koichiro@med.uoeh-u.ac.jp; Honma, Yuichi, E-mail: y-homma@med.uoeh-u.ac.jp; Harada, Masaru, E-mail: msrharada@med.uoeh-u.ac.jp

    2016-09-10

    Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

  11. Reproductive function in the sons of women who experienced stress due to bereavement before and during pregnancy

    DEFF Research Database (Denmark)

    Plana-Ripoll, Oleguer; Li, Jiong; Kesmodel, Ulrik Schiøler

    2017-01-01

    OBJECTIVE: To estimate the association between prenatal exposure to maternal stress and reproductive disorders in Danish men, where prenatal stress exposure was defined as the mother's loss of a close relative during pregnancy or in the 12 months before conception. DESIGN: Population-based cohort...

  12. Stress on Cold Mass Due to the Supporting System of the CMS Coil in the Vacuum Tank

    CERN Document Server

    Farinon, S

    2000-01-01

    This report contains a verification analysis of the stress on cold mass coming from the supporting system of the CMS coil in the vacuum tank. The need to carry out this analysis is related to the high mechanical requirements for $9 Al-alloy mandrels (218 MPa yield at cryogenic temperature), demanding accurate analysis of the impact of supporting system on cylinder stress.

  13. Response of Yield, Yield Components and Nutrient Concentration of Cumin (Cuminum cyminum L. to Mycorrhizal Symbiosis under Salt Stress Conditions

    Directory of Open Access Journals (Sweden)

    M. Bijhani

    2016-01-01

    Full Text Available To study the effects of mycorrhizal inoculation and salinity stress on the growth, yield and nutrient concentrations of cumin (Cuminum cyminum L., an experiment was carried out as split plot in a completely randomized block design at Zabol University Research Farm in 2013. Treatments consisted of three salinity stresses: 1 (control, 5 and 10 dSm-1, was considered as the main treatments, and four levels of mycorrhizal inoculation (Glomus intraradices, G. etanicatum, G. hoi and non-inoculation as control as the sub-treatments. The effects of salinity on all traits under study, except umbers per plant, were significant, and severe stress (10 dSm-1 reduced 100 seed weight, number of seeds per umbel, concentrations of phosphorus, calcium and magnesium in seeds by 17.71, 11.4, 14.95, 46.08, 13.60 %, respectively, as compared to the control. The numbers of seeds per umbel and phosphorus concentration in seed were highest in G. intraradices with 28.4 and 54.4%, respectively as compared to control and umbels per plant was also maximum (9.7 by using G. etanicatum. Mycorrhizal inoculation did not have significant effect on calcium and magnesium concentrations in seeds and 1000 seed weight. However mycorrhiza × salinity stress interaction was significant about concentration of sodium, potassium and sodium to potassium ratio (Na/K in seeds, as well as seed yield and seed number per plant. Among the species of mycorrhiza, applied G. intraradices had better performance in severe salinity (10 dS-1 and increased seed yield and seed number per plant by 28.5 and 47.6%, respectively in comparision control. The results suggested that mycorrhizal inoculation improves water absorption by plant. Yield increases of plants under different salinity regimes dependent on their mycorrhizal inoculation.

  14. Increased albumin excretion in industrial workers due to shift work rather than to prolonged exposure to low concentrations of chlorinated hydrocarbons.

    OpenAIRE

    Boogaard, P J; Caubo, M E

    1994-01-01

    OBJECTIVES--It has been reported that groups of workers in petrochemical industries who have been exposed to low concentrations of chemicals for prolonged periods have an increased urinary albumin excretion compared with unexposed controls. This increase, however, seemed to be unrelated to the extent, duration, and type of exposure. The aim of the present study was to investigate the suggestion that the small increase in albumin excretion might be due to differences in physical workload betwe...

  15. Transient thermal stresses in a transversely isotropic finite hollow circular cylinder due to arbitrary surface heat generations

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Nakanishi, Takanori.

    1980-01-01

    The materials macroscopically regarded as anisotropic materials such as fiber-reinforced composite materials have become to be used for the structural elements at elevated temperature, and the studies on the problem of thermal stress in anisotropic bodies are carried out actively. The unsteady thermal stress in anisotropic finite circular cylinders has not been analyzed so far. In this study, the problem of unsteady thermal stress in an anisotropic finite circular cylinder having arbitrary surface heat generation in axial direction on the internal and external surfaces, and emitting heat from both ends and the internal and external surfaces, was analyzed. For the analysis of temperature distribution, generalized finite Fourier transformation and finite Hankel transformation were used, and thermal stress and thermal displacement were analyzed by the use of the stress function of Singh. By adopting the function used for the transformation nucleus in generalized finite Fourier transformation as the stress function, the analysis was made without separating symmetric and opposite symmetric problems. Numerical calculation was carried out on the basis of the analytical results, and the effects of the anisotropy in thermal conductivity, Young's modulus and linear expansion on unsteady temperature distribution, thermal stress and thermal displacement were quantitatively examined. (Kako, I.)

  16. MRI Shows that Exhaustion Syndrome Due to Chronic Occupational Stress is Associated with Partially Reversible Cerebral Changes.

    Science.gov (United States)

    Savic, I; Perski, A; Osika, W

    2018-03-01

    The present study investigates the cerebral effects of chronic occupational stress and its possible reversibility. Forty-eight patients with occupational exhaustion syndrome (29 women) and 80 controls (47 women) underwent structural magnetic resonance imaging (MRI) and neuropsychological testing. Forty-four participants (25 patients, 19 controls) also completed a second MRI scan after 1-2 years. Only patients received cognitive therapy. The stressed group at intake had reduced thickness in the right prefrontal cortex (PFC) and left superior temporal gyrus (STG), enlarged amygdala volumes, and reduced caudate volumes. Except for the caudate volume, these abnormalities were more pronounced in females. They were all related to perceived stress, which was similar for both genders. Thickness of the PFC also correlated with an impaired ability to down-modulate negative emotions. Thinning of PFC and reduction of caudate volume normalized in the follow-up. The amygdala enlargement and the left STG thinning remained. Longitudinal changes were not detected among controls. Chronic occupational stress was associated with partially reversible structural abnormalities in key regions for stress processing. These changes were dynamically correlated with the degree of perceived stress, highlighting a possible causal link. They seem more pronounced in women, and could be a substrate for an increased cerebral vulnerability to stress-related psychiatric disorders. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. Residual and working stresses in pipe joints in heterogeneous metals, due to common action of welding and service loads

    International Nuclear Information System (INIS)

    Kiselev, S.N.; Voronin, N.N.; Roshchin, V.V.

    1978-01-01

    The stresses in the welded joints of cylindrical shells are studied, which are caused by the total effect of the thermal deformation welding cycles, by the preheats connected with the thermal treatment or operation, and by power loads. Studied were the shell joints made of the steels Kh18N10T and St.3, as well as the joints of three shells made of different metals, St.3+18N1aT steel+copper. The schematic diagram showing the residual stresses set up under effect of different factors are presented. The following has been shown by the study: the preheating of the welded joints of the shells made of diverse metals up to the operational temperatures does not result in obviating the residual stresses. If the welded shells are loaded by the internal pressure up to the stresses of (0.8-O.9) sigmasub(T), in certain cases an essential (up to 60-70%) reduction in the residual welding stresses may be obtained. The effectiveness of a variation in the residual stresses is reduced in the joints that have been thermally treated after welding. The working stresses set up in the welded joints of the shells made of different metals under the operational loading may be essentially reduced through initial preheating with the application of a pressure or without it. The preheating temperature and the pressures applied may be chosen so that to create the residual strains and the stresses of inverse sign as compared with the working stresses

  18. Random regression models to account for the effect of genotype by environment interaction due to heat stress on the milk yield of Holstein cows under tropical conditions.

    Science.gov (United States)

    Santana, Mário L; Bignardi, Annaiza Braga; Pereira, Rodrigo Junqueira; Menéndez-Buxadera, Alberto; El Faro, Lenira

    2016-02-01

    The present study had the following objectives: to compare random regression models (RRM) considering the time-dependent (days in milk, DIM) and/or temperature × humidity-dependent (THI) covariate for genetic evaluation; to identify the effect of genotype by environment interaction (G×E) due to heat stress on milk yield; and to quantify the loss of milk yield due to heat stress across lactation of cows under tropical conditions. A total of 937,771 test-day records from 3603 first lactations of Brazilian Holstein cows obtained between 2007 and 2013 were analyzed. An important reduction in milk yield due to heat stress was observed for THI values above 66 (-0.23 kg/day/THI). Three phases of milk yield loss were identified during lactation, the most damaging one at the end of lactation (-0.27 kg/day/THI). Using the most complex RRM, the additive genetic variance could be altered simultaneously as a function of both DIM and THI values. This model could be recommended for the genetic evaluation taking into account the effect of G×E. The response to selection in the comfort zone (THI ≤ 66) is expected to be higher than that obtained in the heat stress zone (THI > 66) of the animals. The genetic correlations between milk yield in the comfort and heat stress zones were less than unity at opposite extremes of the environmental gradient. Thus, the best animals for milk yield in the comfort zone are not necessarily the best in the zone of heat stress and, therefore, G×E due to heat stress should not be neglected in the genetic evaluation.

  19. Residual stress relaxation due to fretting fatigue in shot peened surfaces of Ti-6Al-4V

    International Nuclear Information System (INIS)

    Martinez, S.A.; Blodgett, M.P.; Mall, S.; Sathish, S.; Namjoshi, S.

    2003-01-01

    Fretting fatigue occurs at locations where the materials are sliding against each other under load. In order to enhance the fatigue life under fretting conditions the surface of the component is shot peened. In general, the shot peening process produces a compressive stress on the surface of the material, thereby increasing the resistance of the material to crack initiation. This paper presents the relaxation of residual stress caused during fretting fatigue. X-ray diffraction has been utilized as the method to measure residual stress in fretting fatigued samples of Ti-6Al-4V

  20. Dynamics of a Lüders Band and Destruction of an Aluminum-Magnesium Alloy, Initiated by a Stress Concentrator

    Science.gov (United States)

    Shibkov, A. A.; Zheltov, M. A.; Gasanov, M. F.; Zolotov, A. E.

    2018-02-01

    Spatio-temporal localization of deformation and the rupture of the aluminum-magnesium AlMg6 alloy, initiated by a geometrical stress concentrator, are studied in situ by video recording at a speed of 500 to 20000 frames/s. It is established that a stress concentrator in the form of a small notch with a depth about 1% of the width of a flat specimen is an attractor of bands of macrolocalized plastic deformation, starting from a Lüders band and ending with the start of the main crack. The key role of intersecting deformation macrobands in the development of the main crack is revealed. Possible micromechanisms of viscous destruction associated with the dynamics of the intersection of deformation bands are discussed.

  1. Risk of a false decision on conformity of an environmental compartment due to measurement uncertainty of concentrations of two or more pollutants.

    Science.gov (United States)

    Pennecchi, Francesca R; Kuselman, Ilya; da Silva, Ricardo J N B; Hibbert, D Brynn

    2018-07-01

    Risks of false decisions in conformity assessment of an environmental compartment due to measurement uncertainty of concentrations of two or more pollutants are discussed. Even if the assessment of conformity for each pollutant in the compartment is successful, the total probability of a false decision concerning the compartment as a whole might still be significant. A model of the total probability of a false decision, formulated on the base of the law of total probability, is used, for example, for a study of test results of total suspended particulate matter (TSPM) concentration in ambient air near to three independent stone quarries located in Israel, as the sources of the air pollution. Total probabilities of underestimation of TSPM concentration (total risk of the inhabitants) and overestimation (total risk of the stone producers) are evaluated as a combination of the particular risks of air conformity assessment concerning TSPM concentration for each quarry. These probabilities characterize conformity of the TSPM concentration in the region of the quarries as a whole. Core code developed in R programming environment for the calculations is provided. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. High concentrations of Na+ and Cl- ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress.

    Science.gov (United States)

    Tavakkoli, Ehsan; Rengasamy, Pichu; McDonald, Glenn K

    2010-10-01

    the effects of the two ions may differ. High Cl(-) concentration reduces the photosynthetic capacity and quantum yield due to chlorophyll degradation which may result from a structural impact of high Cl(-) concentration on PSII. High Na(+) interferes with K(+) and Ca(2+) nutrition and disturbs efficient stomatal regulation which results in a depression of photosynthesis and growth. These results suggest that the importance of Cl(-) toxicity as a cause of reductions in growth and yield under salinity stress may have been underestimated.

  3. Finite element approach to study the behavior of fluid distribution in the dermal regions of human body due to thermal stress

    Directory of Open Access Journals (Sweden)

    M.A. Khanday

    2015-10-01

    Full Text Available The human body is a complex structure where the balance of mass and heat transport in all tissues is necessary for its normal functioning. The stabilities of intracellular and extracellular fluids are important physiological factors responsible for homoeostasis. To estimate the effects of thermal stress on the behavior of extracellular fluid concentration in human dermal regions, a mathematical model based on diffusion equation along with appropriate boundary conditions has been formulated. Atmospheric temperature, evaporation rate, moisture concentration and other factors affecting the fluid concentration were taken into account. The variational finite element approach has been employed to solve the model and the results were interpreted graphically.

  4. β-cell dysfunction due to increased ER stress in a stem cell model of Wolfram syndrome.

    Science.gov (United States)

    Shang, Linshan; Hua, Haiqing; Foo, Kylie; Martinez, Hector; Watanabe, Kazuhisa; Zimmer, Matthew; Kahler, David J; Freeby, Matthew; Chung, Wendy; LeDuc, Charles; Goland, Robin; Leibel, Rudolph L; Egli, Dieter

    2014-03-01

    Wolfram syndrome is an autosomal recessive disorder caused by mutations in WFS1 and is characterized by insulin-dependent diabetes mellitus, optic atrophy, and deafness. To investigate the cause of β-cell failure, we used induced pluripotent stem cells to create insulin-producing cells from individuals with Wolfram syndrome. WFS1-deficient β-cells showed increased levels of endoplasmic reticulum (ER) stress molecules and decreased insulin content. Upon exposure to experimental ER stress, Wolfram β-cells showed impaired insulin processing and failed to increase insulin secretion in response to glucose and other secretagogues. Importantly, 4-phenyl butyric acid, a chemical protein folding and trafficking chaperone, restored normal insulin synthesis and the ability to upregulate insulin secretion. These studies show that ER stress plays a central role in β-cell failure in Wolfram syndrome and indicate that chemical chaperones might have therapeutic relevance under conditions of ER stress in Wolfram syndrome and other forms of diabetes.

  5. Days out of role due to mental and physical illness in the South African stress and health study.

    Science.gov (United States)

    Mall, Sumaya; Lund, Crick; Vilagut, Gemma; Alonso, Jordi; Williams, David R; Stein, Dan J

    2015-03-01

    Both mental and physical disorders can result in role limitation, such as 'days out of role', which have an important impact on national productivity losses. This paper analyses data from the South African Stress and Health Study (SASH) on the association of both mental and physical disorders with days out of role. Face-to-face interviews were conducted with a representative sample of 4,351 adult South Africans. The World Health Organization's Composite International Diagnostic Interview (WHO-CIDI) was used to assess the presence of 21 mental and physical disorders that were grouped into 10 disorder categories for the analysis: major depressive disorder, any anxiety disorders, any substance abuse disorders, headaches or migraine, arthritis, chronic pain, cardiovascular, respiratory, diabetes and digestive disorders. Multiple regression techniques were used to explore associations between individual disorders, comorbid conditions, and annual days spent out of role. The estimated societal effects of the disorders [population attributable risk proportion (PARP)] were obtained. The majority of respondents who reported a mental or physical disorder also reported another disorder (62.98 %). The average number of disorders reported by respondents who had at least one disorder was 2.3. Overall 12.4 % of respondents reported any days out of role due to mental or physical disorder. Anxiety disorders and depression were associated with highest days out of role (28.2 and 27.2, respectively) followed closely by arthritis and pain (24.7 and 21.7, respectively). Any mental disorder was associated with 23.6 days out of role, while any physical disorder was associated with 15.5 days out of role. Of the mental disorders, anxiety disorders had the highest PARP in relation to days out of role (9.0 %) followed by depression (4.8 %) and substance disorder (3.3. %). More than one-third (37.6 %) of days out of role are attributable to physical disorders and 16.1 % to mental

  6. Reduced coupling of oxidative phosphorylation in vivo precedes electron transport chain defects due to mild oxidative stress in mice.

    Directory of Open Access Journals (Sweden)

    Michael P Siegel

    Full Text Available Oxidative stress and mitochondrial function are at the core of many degenerative conditions. However, the interaction between oxidative stress and in vivo mitochondrial function is unclear. We used both pharmacological (2 week paraquat (PQ treatment of wild type mice and transgenic (mice lacking Cu, Zn-superoxide dismutase (SOD1(-/- models to test the effect of oxidative stress on in vivo mitochondrial function in skeletal muscle. Magnetic resonance and optical spectroscopy were used to measure mitochondrial ATP and oxygen fluxes and cell energetic state. In both models of oxidative stress, coupling of oxidative phosphorylation was significantly lower (lower P/O at rest in vivo in skeletal muscle and was dose-dependent in the PQ model. Despite this reduction in efficiency, in vivo mitochondrial phosphorylation capacity (ATPmax was maintained in both models, and ex vivo mitochondrial respiration in permeabilized muscle fibers was unchanged following PQ treatment. In association with the reduced P/O, PQ treatment led to a dose-dependent reduction in PCr/ATP ratio and increased phosphorylation of AMPK. These results indicate that oxidative stress uncouples oxidative phosphorylation in vivo and results in energetic stress in the absence of defects in the mitochondrial electron transport chain.

  7. Oxidative stress and respiratory symptoms due to human exposure to polycyclic aromatic hydrocarbons (PAHs) in Kumasi, Ghana

    International Nuclear Information System (INIS)

    Bortey-Sam, Nesta; Ikenaka, Yoshinori; Akoto, Osei; Nakayama, Shouta M.M.; Asante, Kwadwo A.; Baidoo, Elvis; Obirikorang, Christian; Saengtienchai, Aksorn; Isoda, Norikazu; Nimako, Collins

    2017-01-01

    Studies of polycyclic aromatic hydrocarbons (PAHs) and its metabolites in PM10, soils, rat livers and cattle urine in Kumasi, Ghana, revealed high concentrations and cancer potency. In addition, WHO and IARC have reported an increase in cancer incidence and respiratory diseases in Ghana. Human urine were therefore collected from urban and control sites to: assess the health effects associated with PAHs exposure using malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG); identify any association between OH-PAHs, MDA, 8-OHdG with age and sex; and determine the relationship between PAHs exposure and occurrence of respiratory diseases. From the results, urinary concentrations of the sum of OH-PAHs (∑OHPAHs) were significantly higher from urban sites compared to the control site. Geometric mean concentrations adjusted by specific gravity, GM SG , indicated 2-OHNaphthalene (2-OHNap) (6.01 ± 4.21 ng/mL) as the most abundant OH-PAH, and exposure could be through the use of naphthalene-containing-mothballs in drinking water purification, insect repellent, freshener in clothes and/or “treatment of various ailments”. The study revealed that exposure to naphthalene significantly increases the occurrence of persistent cough (OR = 2.68, CI: 1.43–5.05), persistent headache (OR = 1.82, CI: 1.02–3.26), tachycardia (OR = 3.36, CI: 1.39–8.10) and dyspnea (OR = 3.07, CI: 1.27–7.43) in Kumasi residents. Highest level of urinary 2-OHNap (224 ng/mL) was detected in a female, who reported symptoms of persistent cough, headache, tachycardia, nasal congestion and inflammation, all of which are symptoms of naphthalene exposure according to USEPA. The ∑OHPAHs, 2-OHNap, 2-3-OHFluorenes, and -OHPhenanthrenes showed a significantly positive correlation with MDA and 4-OHPhenanthrene with 8-OHdG, indicating possible lipid peroxidation/cell damage or degenerative disease in some participants. MDA and 8-OHdG were highest in age group 21–60. The present study

  8. {sup 210}Po and {sup 210}Pb concentration of cigarettes traded in Hungary and their estimated dose contribution due to smoking

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, Tibor [Department of Radiochemistry, University of Pannonia, P.O. Box 158, H-8201 Veszprem (Hungary)], E-mail: kt@almos.vein.hu; Somlai, Janos [Department of Radiochemistry, University of Pannonia, P.O. Box 158, H-8201 Veszprem (Hungary); Nagy, Katalin [Department of Rheumatology, Markhot F. Heves County Hospital, Szechenyi ut 27, H-3300 Eger (Hungary); Szeiler, Gabor [Department of Radiochemistry, University of Pannonia, P.O. Box 158, H-8201 Veszprem (Hungary)

    2007-11-15

    It is known that tobacco leaves may contain {sup 210}Pb and {sup 210}Po in significant concentrations. The cumulative alpha-radiation dose due to the radioactive content of inhaled cigarette smoke and the increasing number of lung cancer cases explain the importance of the investigation. The present study investigated the activity concentrations of these two radionuclides in 29 Hungarian cigarette samples. The relation between {sup 210}Po/{sup 210}Pb activity and nicotine/tar content of these cigarettes was also examined. {sup 210}Po was determined by alpha spectrometry using a PIPS detector after chemical leaching and spontaneous deposition of {sup 210}Po on a high nickel-content (25%) stainless steel disk. The {sup 210}Pb activity was calculated from the {sup 210}Po originated from the decay of {sup 210}Pb after a waiting period of eight months. The {sup 210}Po activity concentrations of the measured types of cigarettes ranged from 10.0 to 33.5 mBq/cigarette, and the activity of {sup 210}Pb varied from 9.6 to 32.5 mBq/cigarette. The average annual committed effective dose is estimated to be 185.6{+-}70.6{mu}Sv/y and 58.7{+-}22.7{mu}Sv/y due to cigarette smoking (20 cigarettes/day) for {sup 210}Po and {sup 210}Pb, respectively.

  9. Work-focused cognitive behavioral intervention for psychological complaints in patients on sick leave due to work-related stress: Results from a randomized controlled trial.

    Science.gov (United States)

    Dalgaard, Vita Ligaya; Andersen, Lars Peter Sønderbo; Andersen, Johan Hviid; Willert, Morten Vejs; Carstensen, Ole; Glasscock, David John

    2017-08-22

    Work-related stress is a global problem with negative implications for individuals and society. The purpose of the current study was to evaluate a stress management intervention for patients on sick leave due to work-related stress complaints using a three-armed randomized controlled design. Participants were patients referred from three municipalities to the regional Department of Occupational Medicine. Inclusion criteria were: 1) sick leave due to work-related stress complaints, 2) a diagnosis of adjustment disorder or reactions to severe stress (ICD 10 code: F43,2 - F 43,9 not PTSD) or mild depressive episode (F 32.0). Through a double randomization procedure patients (n = 163) were randomized to either an intervention group (n = 58), a 'control group A' receiving a clinical examination (n = 56), or 'control group B' (n = 49) receiving no offers at the department. The intervention comprised six sessions of individual cognitive behavioral therapy and the offer of a small workplace intervention. Questionnaire data were analyzed with multivariate repeated measurements analysis. Primary outcomes assessed were perceived stress and general mental health. Secondary outcomes were sleep quality and cognitive failures. Follow-up was at four and 10 months after baseline. Complaints were significantly reduced in all groups over time. No group effects were observed between the intervention group and control group A that was clinically assessed. Significant group effects were found for perceived stress and memory when comparing the intervention group to group B, but most likely not due to an intervention effect. Psychological complaints improved substantially over time in all groups, but there was no significant treatment effect on any outcomes when the intervention group was compared to control group A that received a clinical assessment. ISRCTN ISRCTN91404229. Registered 03 August 2012 (retrospectively registered).

  10. Hypoxic stress induces, but cannot sustain trophoblast stem cell differentiation to labyrinthine placenta due to mitochondrial insufficiency

    Directory of Open Access Journals (Sweden)

    Yufen Xie

    2014-11-01

    Full Text Available Dysfunctional stem cell differentiation into placental lineages is associated with gestational diseases. Of the differentiated lineages available to trophoblast stem cells (TSC, elevated O2 and mitochondrial function are necessary to placental lineages at the maternal–placental surface and important in the etiology of preeclampsia. TSC lineage imbalance leads to embryonic failure during uterine implantation. Stress at implantation exacerbates stem cell depletion by decreasing proliferation and increasing differentiation. In an implantation site O2 is normally ~2%. In culture, exposure to 2% O2 and fibroblast growth factor 4 (FGF4 enabled the highest mouse TSC multipotency and proliferation. In contrast, hypoxic stress (0.5% O2 initiated the most TSC differentiation after 24 h despite exposure to FGF4. However, hypoxic stress supported differentiation poorly after 4–7 days, despite FGF4 removal. At all tested O2 levels, FGF4 maintained Warburg metabolism; mitochondrial inactivity and aerobic glycolysis. However, hypoxic stress suppressed mitochondrial membrane potential and maintained low mitochondrial cytochrome c oxidase (oxidative phosphorylation/OxPhos, and high pyruvate kinase M2 (glycolysis despite FGF4 removal. Inhibiting OxPhos inhibited optimum differentiation at 20% O2. Moreover, adding differentiation-inducing hyperosmolar stress failed to induce differentiation during hypoxia. Thus, differentiation depended on OxPhos at 20% O2; hypoxic and hyperosmolar stresses did not induce differentiation at 0.5% O2. Hypoxia-limited differentiation and mitochondrial inhibition and activation suggest that differentiation into two lineages of the labyrinthine placenta requires O2 > 0.5–2% and mitochondrial function. Stress-activated protein kinase increases an early lineage and suppresses later lineages in proportion to the deviation from optimal O2 for multipotency, thus it is the first enzyme reported to prioritize differentiation.

  11. Quality of life among post-menopausal women due to oxidative stress boosted by dysthymia and anxiety.

    Science.gov (United States)

    Sánchez-Rodríguez, Martha A; Castrejón-Delgado, Lizett; Zacarías-Flores, Mariano; Arronte-Rosales, Alicia; Mendoza-Núñez, Víctor Manuel

    2017-01-03

    Menopause is the onset of aging in women. During this process, some women experience physical changes that may impact upon their psychological and social status, also affecting their quality of life. Furthermore, several psychological changes following menopause have been shown to act as pro-oxidant, but the association between the psychological status that modify the quality of life and oxidative stress in postmenopausal women is still unclear. The aim of this study was to determinate the relationship between oxidative stress with psychological disturbances, low self-esteem, depressive mood and anxiety, and quality of life in the postmenopausal women. We carried out a cross-sectional study with101 premenopausal and 101 postmenopausal women from Mexico City. As markers of oxidative stress we measured plasma lipoperoxide levels, erythrocyte superoxide dismutase and glutathione peroxidase activities, and total antioxidant status. We calculate a stress score as global oxidative stress status, with cut-off values for each parameter; this score range from 0 to 6, representing the severity of markers modifications. All the women were rated using the Coopersmith Self-Esteem Inventory, the Zung Self-Rating Anxiety and the Zung Self-Rating Depression Scales, and the WHO Quality of Life-brief. The postmenopausal women with low quality of life in the WHO Quality of Life-brief and their subscales had higher stress score compared with premenopausal women with high quality of life (p Life-brief scores (r = -0.266, p Life-brief, after adjusted for pro-oxidant factors. Zung Self-Rating Anxiety and Zung Self-Rating Depression Scales scores also contribute to increase lipoperoxides levels, but not significant. Our findings suggest that oxidative stress is increased in postmenopausal women with psychological disturbances and low quality of life.

  12. Stress at birth: plasma noradrenaline concentrations of women in labour and in cord blood.

    Science.gov (United States)

    Messow-Zahn, K; Sarafoff, M; Riegel, K P

    1978-03-15

    Radioenzymatically measured plasma noradrenaline concentrations, present at birth in umbilical veins of 19 healthy, 17 acutely asphyxiated, and 9 chronically distressed newborn infants were found to be elevated above maternal values proportional to the degree of distress and to plasma H ion concentrations.

  13. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  14. Comparative Salt Stress Study on Intracellular Ion Concentration in Marine and Salt-adapted Freshwater Strains of Microalgae

    Directory of Open Access Journals (Sweden)

    Ahmad Farhad TALEBI

    2013-08-01

    Full Text Available Salinity imposes significant stresses in various living organisms including microalgae. High extracellular concentration of Na+ directly influences ionic balance inside the cell and subsequently the cellular activities. In the present study, the effect of such stress on growth and intracellular ions concentration (IIC of Dunaliella salina and Chlorella Spp. was investigated. IIC was analyzed using Ion chromatography technique. D. salina showed the highest degree of resistance to increase in salinity as little changes occurred both in IIC and in growth parameters. D. salina could maintain the balance of K+ inside the cell and eject the excess Na+ even at NaCl concentrations above 1M. Moreover, D. salina accumulated β-carotene in order to protect its photosynthetic apparatus. Among Chlorella species, C. vulgaris showed signs of adaptation to high content of salinity, though it is a fresh water species by nature. Moreover, the response shown by C. vulgaris to rise in salinity was even stronger than that of C. salina, which is presumably a salt-water resistant species. In fact, C. vulgaris could maintain intracellular K+ better than C. salina in response to increasing salinity, and as a result, it could survive at NaCl concentrations as high as 0.75 M. Marine strains such as D. salina well cope with the fluctuations in salinity through the existing adaptation mechanisms i.e. maintaining the K+/N+ balance inside the cell, K+ accumulation and Na+ ejection, accumulation of photosynthetic pigments like β-carotene.

  15. Use of MICRAS code on the evaluation of the maximum radionuclides concentrations due to transport/migration of decay chain in groundwaters

    International Nuclear Information System (INIS)

    Aquino Branco, O.E. de

    1995-01-01

    This paper presents a methodology for the evaluation of the maximum radionuclides concentrations in groundwaters, due to the transport/migration of decay chains. Analytical solution of the equations system is difficult, even if only three elements of the decay chain are considered. Therefore, a numerical solution is most convenient. An application of the MICRAS code, developed to assess maximum concentrations of each radionuclide, starting with the initial concentrations, is presented. The maximum concentration profile for 226 Ra, calculated using MICRAS, is compared with the results obtained through an analytical and a numerical model. The fitness of results is considered good. Simplified models, like the one represented by the application of MICRAS, are largely employed in the section in the selection and characterization of sites for radioactive wastes repositories and in studies of safety evaluation for the same purpose. A detailed analysis of the transport/migration of contaminants in aquifers requires a large quantify of data from the site and from the installation as well, which makes this analysis expensive and inviable during the preliminary phases of the studies. (author). 6 refs, 1 fig, 1 tab

  16. A simplified method to calculate the stresses in straight pipes due to laminar flow of a stratified medium with two different temperatures

    International Nuclear Information System (INIS)

    Cutrim, J.H.; Kizivat, V.

    1984-01-01

    A simplified method to calculate the stresses in straight pipes due to laminar flow of a stratified medium with two different temperatures is presented. It is based on the equilibrium equations and conservative assumptions as usual in practice. Numerical results are obtained for the 'banana' and 'pera' modes of deformation due to thermal stratification; the former case appears to be most important. In order to be able to perform such a fatigue damage analysis in practice under several complex load conditions, an existing program for fatigue damage analysis was provided with more substantial details. All the assumptions crucial for the use of ASME code were retained. The inclusion of stresses due to stratifications in the fatigue damage analysis is completed through extension of ASME NB 3650. (Author) [pt

  17. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

  18. Oxidative stress and antioxidant responses to increasing concentrations of trivalent chromium in the Andean crop species Chenopodium quinoa Willd.

    Science.gov (United States)

    Scoccianti, Valeria; Bucchini, Anahi E; Iacobucci, Marta; Ruiz, Karina B; Biondi, Stefania

    2016-11-01

    Quinoa (Chenopodium quinoa Willd), an ancient Andean seed crop, exhibits exceptional nutritional properties and resistance to abiotic stress. The species' tolerance to heavy metals has, however, not yet been investigated nor its ability to take up and translocate chromium (Cr). This study aimed to investigate the metabolic adjustments occurring upon exposure of quinoa to several concentrations (0.01-5mM) of CrCl3. Young hydroponically grown plants were used to evaluate Cr uptake, growth, oxidative stress, and other biochemical parameters three and/or seven days after treatment. Leaves accumulated the lowest amounts of Cr, while roots and stems accumulated the most at low and at high metal concentrations, respectively. Fresh weight and photosynthetic pigments were reduced only by the higher Cr(III) doses. Substantially increased lipid peroxidation, hydrogen peroxide, and proline levels were observed only with 5mM Cr(III). Except for a significant decrease at day 7 with 5mM Cr(III), total polyphenols and flavonoids maintained control levels in Cr(III)-treated plants, whereas antioxidant activity increased in a dose-dependent manner. Maximum polyamine accumulation was observed in 1mM CrCl3-treated plants. Even though α- and γ-tocopherols also showed enhanced levels only with the 1mM concentration, tyrosine aminotransferase (TAT, EC 2.6.1.5) activity increased under Cr(III) treatment in a dose- and time-dependent manner. Taken together, results suggest that polyamines, tocopherols, and TAT activity could contribute to tolerance to 1mM Cr(III), but not to the highest concentration that, instead, generated oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Hair cortisol concentrations and cortisol stress reactivity predict PTSD symptom increase after trauma exposure during military deployment.

    Science.gov (United States)

    Steudte-Schmiedgen, Susann; Stalder, Tobias; Schönfeld, Sabine; Wittchen, Hans-Ulrich; Trautmann, Sebastian; Alexander, Nina; Miller, Robert; Kirschbaum, Clemens

    2015-09-01

    Previous evidence on endocrine risk markers for posttraumatic stress disorder (PTSD) has been inconclusive. Here, we report results of the first prospective study to investigate whether long-term hair cortisol levels and experimentally-induced cortisol stress reactivity are predictive of the development of PTSD symptomatology in response to trauma during military deployment. Male soldiers were examined before deployment to Afghanistan and at a 12-month post-deployment follow-up using dimensional measures for psychopathological symptoms. The predictive value of baseline (i) hair cortisol concentrations (HCC, N=90) and (ii) salivary cortisol stress reactivity (measured by the Trier Social Stress Test, N=80) for the development of PTSD symptomatology after being exposed to new-onset traumatic events was analyzed. Baseline cortisol activity significantly predicted PTSD symptom change from baseline to follow-up upon trauma exposure. Specifically, our results consistently revealed that lower HCC and lower cortisol stress reactivity were predictive of a greater increase in PTSD symptomatology in soldiers who had experienced new-onset traumatic events (explaining 5% and 10.3% of variance, respectively). Longitudinal analyses revealed an increase in HCC from baseline to follow-up and a trend for a negative relationship between HCC changes and the number of new-onset traumatic events. Additional pre-deployment analyses revealed that trauma history was reflected in lower HCC (at trend level) and that HCC were negatively related to stressful load. Our data indicate that attenuated cortisol secretion is a risk marker for subsequent development of PTSD symptomatology upon trauma exposure. Future studies are needed to confirm our findings in other samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Implicit constitutive models with a thermodynamic basis: a study of stress concentration

    Science.gov (United States)

    Bridges, C.; Rajagopal, K. R.

    2015-02-01

    Motivated by the recent generalization of the class of elastic bodies by Rajagopal (Appl Math 48:279-319, 2003), there have been several recent studies that have been carried out within the context of this new class. Rajagopal and Srinivasa (Proc R Soc Ser A 463:357-367, 2007, Proc R Soc Ser A: Math Phys Eng Sci 465:493-500, 2009) provided a thermodynamic basis for such models and appealing to the idea that rate of entropy production ought to be maximized they developed nonlinear rate equations of the form where T is the Cauchy stress and D is the stretching tensor as well as , where S is the Piola-Kirchhoff stress tensor and E is the Green-St. Venant strain tensor. We follow a similar procedure by utilizing the Gibb's potential and the left stretch tensor V from the Polar Decomposition of the deformation gradient, and we show that when the displacement gradient is small one arrives at constitutive relations of the form . This is, of course, in stark contrast to traditional elasticity wherein one obtains a single model, Hooke's law, when the displacement gradient is small. By solving a classical boundary value problem, with a particular form for f( T), we show that when the stresses are small, the strains are also small which is in agreement with traditional elasticity. However, within the context of our model, when the stress blows up the strains remain small, unlike the implications of Hooke's law. We use this model to study boundary value problems in annular domains to illustrate its efficacy.

  1. Effect of Chinese traditional medicine anti-fatigue prescription on the concentration of the serum testosterone and cortisol in male rats under stress of maximum intensive training

    International Nuclear Information System (INIS)

    Dong Ling; Si Xulan

    2008-01-01

    Objective: To study the effect of chinese traditional medicine anti-fatigue prescription on the concentration of the serum testosterone (T) and cortisol (C) in male rats under the stress of maximum intensive training. Methods: Wistar male rat models of stress under maximum intensity training were established (n=40) and half of them were treated with Chinese traditional medicine anti-fatigue prescription twenty undisturbed rats served as controls. Testosterone and cortisol serum levels were determined with RIA at the end of the seven weeks' experiment. Results: Maximum intensive training would cause the level of the serum testosterone lowered, the concentration of the cortisol elevated and the ratio of T/C reduced. The serum T levels and T/C ratio were significantly lower and cortisol levels significantly higher in the untreated models than those in the treated models and controls (P<0.01). The levels of the two hormones were markedly corrected in the treated models with no significantly differences from those in the controls. However, the T/C ratio was still significantly lower than that in the controls (P <0.05) due to a relatively slightly greater degree of reduction of T levels. Conclusion: Anti-fatigue prescription can not only promote the recovery of fatigue after the maximum intensive training but also strengthen the anabolism of the rats. (authors)

  2. Radiation dose-dependent risk on individuals due to ingestion of uranium and radon concentration in drinking water samples of four districts of Haryana, India

    Science.gov (United States)

    Panghal, Amanjeet; Kumar, Ajay; Kumar, Suneel; Singh, Joga; Sharma, Sumit; Singh, Parminder; Mehra, Rohit; Bajwa, B. S.

    2017-06-01

    Uranium gets into drinking water when the minerals containing uranium are dissolved in groundwater. Uranium and radon concentrations have been measured in drinking water samples from different water sources such as hand pumps, tube wells and bore wells at different depths from various locations of four districts (Jind, Rohtak, Panipat and Sonipat) of Haryana, India, using the LED flourimetry technique and RAD7, electronic silicon solid state detector. The uranium (238U) and radon (222Rn) concentrations in water samples have been found to vary from 1.07 to 40.25 µg L-1 with an average of 17.91 µg L-1 and 16.06 ± 0.97 to 57.35 ± 1.28 Bq L-1 with an average of 32.98 ± 2.45 Bq L-1, respectively. The observed value of radon concentration in 43 samples exceeded the recommended limits of 11 Bq L-1 (USEPA) and all the values are within the European Commission recommended limit of 100 Bq L-1. The average value of uranium concentration is observed to be within the safe limit recommended by World Health Organization (WHO) and Atomic Energy Regulatory Board. The annual effective dose has also been measured in all the water samples and is found to be below the prescribed dose limit of 100 µSv y-1 recommended by WHO. Risk assessment of uranium in water is also calculated using life time cancer risk, life time average daily dose and hazard quotient. The high uranium concentration observed in certain areas is due to interaction of ground water with the soil formation of this region and the local subsurface geology of the region.

  3. Estimation of Radionuclide Concentrations and Average Annual Committed Effective Dose due to Ingestion for the Population in the Red River Delta, Vietnam.

    Science.gov (United States)

    Van, Tran Thi; Bat, Luu Tam; Nhan, Dang Duc; Quang, Nguyen Hao; Cam, Bui Duy; Hung, Luu Viet

    2018-02-16

    Radioactivity concentrations of nuclides of the 232 Th and 238 U radioactive chains and 40 K, 90 Sr, 137 Cs, and 239+240 Pu were surveyed for raw and cooked food of the population in the Red River delta region, Vietnam, using α-, γ-spectrometry, and liquid scintillation counting techniques. The concentration of 40 K in the cooked food was the highest compared to those of other radionuclides ranging from (23 ± 5) (rice) to (347 ± 50) Bq kg -1 dw (tofu). The 210 Po concentration in the cooked food ranged from its limit of detection (LOD) of 5 mBq kg -1  dw (rice) to (4.0 ± 1.6) Bq kg -1  dw (marine bivalves). The concentrations of other nuclides of the 232 Th and 238 U chains in the food were low, ranging from LOD of 0.02 Bq kg -1  dw to (1.1 ± 0.3) Bq kg -1  dw. The activity concentrations of 90 Sr, 137 Cs, and 239+240 Pu in the food were minor compared to that of the natural radionuclides. The average annual committed effective dose to adults in the study region was estimated and it ranged from 0.24 to 0.42 mSv a -1 with an average of 0.32 mSv a -1 , out of which rice, leafy vegetable, and tofu contributed up to 16.2%, 24.4%, and 21.3%, respectively. The committed effective doses to adults due to ingestion of regular diet in the Red River delta region, Vietnam are within the range determined in other countries worldwide. This finding suggests that Vietnamese food is safe for human consumption with respect to radiation exposure.

  4. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    International Nuclear Information System (INIS)

    Yoshida, Go J.; Saya, Hideyuki

    2014-01-01

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 high / Fbw7 high / c-Myc low and proliferative cancer stem-like cells with CD44v8-10 high / Fbw7 low / c-Myc high

  5. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  6. Stress-induced grey matter loss determined by MRI is primarily due to loss of dendrites and their synapses.

    Science.gov (United States)

    Kassem, Mustafa S; Lagopoulos, Jim; Stait-Gardner, Tim; Price, William S; Chohan, Tariq W; Arnold, Jonathon C; Hatton, Sean N; Bennett, Maxwell R

    2013-04-01

    Stress, unaccompanied by signs of post-traumatic stress disorder, is known to decrease grey matter volume (GMV) in the anterior cingulate cortex (ACC) and hippocampus but not the amygdala in humans. We sought to determine if this was the case in stressed mice using high-resolution magnetic resonance imaging (MRI) and to identify the cellular constituents of the grey matter that quantitatively give rise to such changes. Stressed mice showed grey matter losses of 10 and 15 % in the ACC and hippocampus, respectively but not in the amygdala or the retrosplenial granular area (RSG). Concurrently, no changes in the number or volumes of the somas of neurons, astrocytes or oligodendrocytes were detected. A loss of synaptic spine density of up to 60 % occurred on different-order dendrites in the ACC and hippocampus (CA1) but not in the amygdala or RSG. The loss of spines was accompanied by decreases in cumulative dendritic length of neurons of over 40 % in the ACC and hippocampus (CA1) giving rise to decreases in volume of dendrites of 2.6 mm(3) for the former and 0.6 mm(3) for the latter, with no change in the amygdala or RSG. These values are similar to the MRI-determined loss of GMV following stress of 3.0 and 0.8 mm(3) in ACC and hippocampus, respectively, with no changes in the amygdala or RSG. This quantitative study is the first to relate GMV changes in the cortex measured with MRI to volume changes in cellular constituents of the grey matter.

  7. Early identification in primary health care of people at risk for sick leave due to work-related stress - study protocol of a randomized controlled trial (RCT).

    Science.gov (United States)

    Holmgren, Kristina; Sandheimer, Christine; Mårdby, Ann-Charlotte; Larsson, Maria E H; Bültmann, Ute; Hange, Dominique; Hensing, Gunnel

    2016-11-25

    Early identification of persons at risk of sickness absence due to work-related stress is a crucial problem for society in general, and primary health care in particular. Tho date, no established method to do this exists. This project's aim is to evaluate whether systematic early identification of work-related stress can prevent sickness absence. This paper presents the study design, procedure and outcome measurements, as well as allocation and baseline characteristics of the study population. The study is a two-armed randomized controlled trial with follow-up at 3, 6 and 12 months. Non-sick-listed employed women and men, aged 18 to 64 years, who had mental and physical health complaints and sought care at primary health care centers (PHCC) were eligible to participate. At baseline work-related stress was measured by the Work Stress Questionnaire (WSQ), combined with feedback at consultation, at PHCC. The preventive intervention included early identification of work-related stress by the WSQ, GP training in the use of WSQ, GP feedback at consultation and finding suitable preventive measures. A process evaluation was used to explore how to facilitate future implementation and structural use of the WSQ at the PHCC. The primary outcome to compare the preventive sick leave intervention by the general practitioner (GP) versus treatment as usual is sick leave data obtained from the Swedish Social Insurance Agency register. Early screening for sick leave due to work-related stress makes it possible not only to identify those at risk for sick leave, but also to put focus on the patient's specific work-related stress problems, which can be helpful in finding suitable preventive measures. This study investigates if use of the WSQ by GPs at PHCCs, combined with feedback at consultation, prevents future sickness absence. ClinicalTrials.gov. Identifier: NCT02480855 . Registered 20 May 2015.

  8. Chronic restraint stress promotes learning and memory impairment due to enhanced neuronal endoplasmic reticulum stress in the frontal cortex and hippocampus in male mice.

    Science.gov (United States)

    Huang, Rong-Rong; Hu, Wen; Yin, Yan-Yan; Wang, Yu-Chan; Li, Wei-Ping; Li, Wei-Zu

    2015-02-01

    Chronic stress has been implicated in many types of neurodegenerative diseases, such as Alzheimer's disease (AD). In our previous study, we demonstrated that chronic restraint stress (CRS) induced reactive oxygen species (ROS) overproduction and oxidative damage in the frontal cortex and hippocampus in mice. In the present study, we investigated the effects of CRS (over a period of 8 weeks) on learning and memory impairment and endoplasmic reticulum (ER) stress in the frontal cortex and hippocampus in male mice. The Morris water maze was used to investigate the effects of CRS on learning and memory impairment. Immunohistochemistry and immunoblot analysis were also used to determine the expression levels of protein kinase C α (PKCα), 78 kDa glucose-regulated protein (GRP78), C/EBP-homologous protein (CHOP) and mesencephalic astrocyte-derived neurotrophic factor (MANF). The results revealed that CRS significantly accelerated learning and memory impairment, and induced neuronal damage in the frontal cortex and hippocampus CA1 region. Moreover, CRS significantly increased the expression of PKCα, CHOP and MANF, and decreased that of GRP78 in the frontal cortex and hippocampus. Our data suggest that exposure to CRS (for 8 weeks) significantly accelerates learning and memory impairment, and the mechanisms involved may be related to ER stress in the frontal cortex and hippocampus.

  9. Is gill cortisol concentration a good acute stress indicator in fish? A study in rainbow trout and zebrafish.

    Science.gov (United States)

    Gesto, Manuel; Hernández, Juan; López-Patiño, Marcos A; Soengas, José L; Míguez, Jesús M

    2015-10-01

    Cortisol is the main biomarker of physiological stress in fish. It is usually measured in plasma, which requires blood collection. Though cortisol is produced in the anterior kidney, it can diffuse easily through cell membranes due to its lipophilic nature. Taking advantage of that, some non-invasive techniques have been developed to measure cortisol directly in the water from fish-holding tanks, in skin mucus or in scales. In this study, we explored the possibility to analyze fish cortisol from gill filaments as a reliable acute stress marker. Our results show that gill cortisol levels correlate well with plasma cortisol levels in both rainbow trout and zebrafish exposed or not to an acute stress protocol. Measuring cortisol in gill filaments increases the available possibilities for stress assessment in fish. Although this approach should yet be tested for its use with other stressors, it has several advantages: In relatively large fish (i.e. above 30 g) gill cortisol levels could be measured in vivo. Sampling of gill biopsies is very fast and easy, and the procedure does not induce stress if properly performed, making it an ideal option for in vivo stress assessment. In small fish, the use of gill tissue to measure cortisol has important technical advantages with respect to the current methods using whole-body homogenates. Gill homogenates could be used directly for ELISA cortisol analysis, avoiding the need of tedious and expensive cortisol extraction protocols, and, since no organic solvent is required, contributing for a more environmentally friendly analysis. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Sublethal effects of a metal contamination due to uranium mine tailings in the three-spined stickleback (Gasterosteus aculeatus L.). Implication in the susceptibility to a biological stress

    International Nuclear Information System (INIS)

    Le Guernic, Antoine

    2015-01-01

    Uranium extraction has resulted in a remobilization of this actinide into mine surrounding ecosystems. Uses of metal salts during mining site rehabilitation, and the natural presence of metals have increased the metal contamination in hydro systems submitted to mine tailings. In situ experiments were conducted in two former French uranium mining sites. Three-spined stickleback caging was used to determine the sublethal effects of this metal mixture on this freshwater fish, as well as its effects on fish susceptibility to a sudden biological stress. This pollution, characterised by higher metal concentrations (especially for uranium), has led to an oxidative stress in sticklebacks visible through several bio-markers, and other effects dependent on the study site. The polymetallic contamination has modified the stickleback responses to the biological stress, by preventing their phagocytic and antioxidant responses. This work has reinforced the interest of the caging technique during environmental studies and that of immuno-markers in a multi-bio-marker approach. (author)

  11. Serum brain-derived neurotrophic factor (BDNF) concentrations in pregnant women with post-traumatic stress disorder and comorbid depression.

    Science.gov (United States)

    Yang, Na; Gelaye, Bizu; Zhong, Qiuyue; Rondon, Marta B; Sanchez, Sixto E; Williams, Michelle A

    2016-12-01

    There is accumulating evidence for the role of brain-derived neurotrophic factor (BDNF) in the pathophysiology of depression. However, the role of BDNF in the pathophysiology of post-traumatic stress disorder (PTSD) remains controversial, and no study has assessed BDNF concentrations among pregnant women with PTSD. We examined early-pregnancy BDNF concentrations among women with PTSD with and without depression. A total of 2928 women attending prenatal care clinics in Lima, Peru, were recruited. Antepartum PTSD and depression were evaluated using PTSD Checklist-Civilian Version (PCL-C) and Patient Health Questionnaire-9 (PHQ-9) scales, respectively. BDNF concentrations were measured in a subset of the cohort (N = 944) using a competitive enzyme-linked immunosorbent assay (ELISA). Logistic regression procedures were used to estimate odds ratios (OR) and 95 % confidence intervals (95 % CI). Antepartum PTSD (37.4 %) and depression (27.6 %) were prevalent in this cohort of low-income pregnant Peruvian women. Approximately 19.9 % of participants had comorbid PTSD-depression. Median serum BDNF concentrations were lower among women with comorbid PTSD-depression as compared with women without either condition (median [interquartile range], 20.44 [16.97-24.30] vs. 21.35 [17.33-26.01] ng/ml; P = 0.06). Compared to the referent group (those without PTSD and depression), women with comorbid PTSD-depression were 1.52-fold more likely to have low (BDNF concentrations (OR = 1.52; 95 % CI 1.00-2.31). We observed no evidence of reduced BDNF concentrations among women with isolated PTSD. BDNF concentrations in early pregnancy were only minimally and non-significantly reduced among women with antepartum PTSD. Reductions in BDNF concentrations were more pronounced among women with comorbid PTSD-depression.

  12. Influence of reductant and germanium concentration on the growth and stress development of germanium nanocrystals in silicon oxide matrix

    International Nuclear Information System (INIS)

    Chew, H G; Zheng, F; Choi, W K; Chim, W K; Foo, Y L; Fitzgerald, E A

    2007-01-01

    Germanium (Ge) nanocrystals have been synthesized by annealing co-sputtered SiO 2 -Ge samples in N 2 or forming gas (90% N 2 +10% H 2 ) at temperatures ranging from 700 to 1000 deg. C. We concluded that the annealing ambient, temperature and Ge concentration have a significant influence on the formation and evolution of the nanocrystals. We showed that a careful selective etching of the annealed samples in hydrofluoric acid solution enabled the embedded Ge nanocrystals to be liberated from the SiO 2 matrix. From the Raman results of the as-grown and the liberated nanocrystals, we established that the nanocrystals generally experienced compressive stress in the oxide matrix and the evolution of these stress states was intimately linked to the distribution, density, size and quality of the Ge nanocrystals

  13. Higher concentrations of nanoscale zero-valent iron (nZVI) in soil induced rice chlorosis due to inhibited active iron transportation

    International Nuclear Information System (INIS)

    Wang, Jie; Fang, Zhanqiang; Cheng, Wen; Yan, Xiaomin; Tsang, Pokeung Eric; Zhao, Dongye

    2016-01-01

    In this study, the effects of concentrations 0, 100, 250, 500, 750 and 1000 mg kg"−"1 of nanoscale zero-valent iron (nZVI) on germination, seedlings growth, physiology and toxicity mechanisms were investigated. The results showed that nZVI had no effect on germination, but inhibited the rice seedlings growth in higher concentrations (>500 mg kg"−"1 nZVI). The highest suppression rate of the length of roots and shoots reached 46.9% and 57.5%, respectively. The 1000mg kg"−"1 nZVI caused the highest suppression rates for chlorophyll and carotenoids, at 91.6% and 85.2%, respectively. In addition, the activity of antioxidant enzymes was altered by the translocation of nanoparticles and changes in active iron content. Visible symptoms of iron deficiency were observed at higher concentrations, at which the active iron content decreased 61.02% in the shoots, but the active iron content not decreased in roots. Interestingly, the total and available amounts of iron in the soil were not less than those in the control. Therefore, the plants iron deficiency was not caused by (i) deficiency of available iron in the soil and (ii) restraint of the absorption that plant takes in the available iron, while induced by (ⅲ) the transport of active iron from the root to the shoot was blocked. The cortex tissues were seriously damaged by nZVI which was transported from soil to the root, these were proved by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). This current study shows that the mechanism of iron deficiency in rice seedling was due to transport of active iron from the root to the shoot blocked, which was caused by the uptake of nZVI. - Highlights: • Higher concentrations of nZVI induced iron deficiency in rice seedlings visibly. • nZVI was taken in rice seedlings and transported form root to shoot. • The pathway of active iron transport from root to shoot was inhibited. • The cortex tissues

  14. Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Samira Abdulai-Saiku

    2018-01-01

    Full Text Available Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change.  Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma gondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.

  15. Stress Concentration in the Bulk Cr2O3: Effects of Temperature and Point Defects

    Directory of Open Access Journals (Sweden)

    Mazharul M. Islam

    2017-01-01

    Full Text Available Modeling the growth and failure of passive oxide films formed on stainless steels is of general interest for the use of stainless steel as structural material and of special interest in the context of life time extension of light water reactors in nuclear power plants. Using the DFT+U approach, a theoretical investigation on the resistance to failure of the chromium-rich inner oxide layer formed at the surface of chromium-containing austenitic alloys (stainless steel and nickel based alloys has been performed. The investigations were done for periodic bulk models. The data at the atomic scale were extrapolated by using the Universal Binding Energy Relationships (UBERs model in order to estimate the mechanical behavior of a 10 μm thick oxide scale. The calculated stress values are in good agreement with experiments. Tensile stress for the bulk chromia was observed. The effects of temperature and structural defects on cracking were investigated. The possibility of cracking intensifies at high temperature compared to 0 K investigations. Higher susceptibility to cracking was observed in presence of defects compared to nondefective oxide, in agreement with experimental observation.

  16. Study on the stress changes due to the regional groundwater exploitation based on a 3-D fully coupled poroelastic model: An example of the North China Plain

    Science.gov (United States)

    Cheng, H.; Zhang, H.; Pang, Y. J.; Shi, Y.

    2017-12-01

    With the quick urban development, over-exploitation of groundwater resources becomes more and more intense, which leads to not only widespread groundwater depression cones but also a series of harsh environmental and geological hazards. Among which, the most intuitive phenomenon is the ground subsidence in loose sediments. However, another direct consequence triggered by the groundwater depletion is the substantial crustal deformation and potential modulation of crustal stress underneath the groundwater over-pumping zones. In our previous 3-D viscoelastic finite element model, we found that continuous over-exploitation of groundwater resources in North China Plain during the past 60 years give rise to crustal-scale uplift reaching 4.9cm, with the Coulomb failure stress decreasing by up to 12 kPa, which may inhibit the nucleation of possible big earthquake events. Furthermore, according to the effective pressure principle and lab experiments, the pore pressure may also have changed due to the reduced water level. In order to quantitatively analyze the stress changes due to the regional groundwater exploitation in North China Plain, a three-dimensional fully coupled poroelastic finite element model is developed in this study. The high resolution topography, grounwater level fluctuation, fault parameters and etc, are taken into consideration. Further, the changes of Coulomb Failure Stress, in correspondence to elastic stress and pore pressure changes induced by fluid diffusion are calculated. Meanwhile, the elastic strain energy accumulation in region due to the regional groundwater exploitation is obtained. Finally, we try to analyze the seismic risk of major faults within North China Plain to further discuss the regional seismic activities.

  17. Uncovering the local inelastic interactions during manufacture of ductile cast iron: How the substructure of the graphite particles can induce residual stress concentrations in the matrix

    Science.gov (United States)

    Andriollo, Tito; Hellström, Kristina; Sonne, Mads Rostgaard; Thorborg, Jesper; Tiedje, Niels; Hattel, Jesper

    2018-02-01

    Recent X-ray diffraction (XRD) measurements have revealed that plastic deformation and a residual elastic strain field can be present around the graphite particles in ductile cast iron after manufacturing, probably due to some local mismatch in thermal contraction. However, as only one component of the elastic strain tensor could be obtained from the XRD data, the shape and magnitude of the associated residual stress field have remained unknown. To compensate for this and to provide theoretical insight into this unexplored topic, a combined experimental-numerical approach is presented in this paper. First, a material equivalent to the ductile cast iron matrix is manufactured and subjected to dilatometric and high-temperature tensile tests. Subsequently, a two-scale hierarchical top-down model is devised, calibrated on the basis of the collected data and used to simulate the interaction between the graphite particles and the matrix during manufacturing of the industrial part considered in the XRD study. The model indicates that, besides the viscoplastic deformation of the matrix, the effect of the inelastic deformation of the graphite has to be considered to explain the magnitude of the XRD strain. Moreover, the model shows that the large elastic strain perturbations recorded with XRD close to the graphite-matrix interface are not artifacts due to e.g. sharp gradients in chemical composition, but correspond to residual stress concentrations induced by the conical sectors forming the internal structure of the graphite particles. In contrast to common belief, these results thus suggest that ductile cast iron parts cannot be considered, in general, as stress-free at the microstructural scale.

  18. Maxwell-Cattaneo Heat Convection and Thermal Stresses Responses of a Semi-Infinite Medium to High-Speed Laser Heating due to High Speed Laser Heating

    Directory of Open Access Journals (Sweden)

    Abdallah I. A.

    2009-07-01

    Full Text Available Based on Maxwell-Cattaneo convection equation, the thermoelasticity problem is in- vestigated in this paper. The analytic solution of a boundary value problem for a semi- infinite medium with traction free surface heated by a high-speed laser-pulses have Dirac temporal profile is solved. The temperature, the displacement and the stresses distributions are obtained analytically using the Laplace transformation, and discussed at small time duration of the laser pulses. A numerical study for Cu as a target is performed. The results are presented graphically. The obtained results indicate that the small time duration of the laser pulses has no e ect on the finite velocity of the heat con- ductivity, but the behavior of the stress and the displacement distribution are affected due to the pulsed heating process and due to the structure of the governing equations.

  19. Stress State Analysis and Failure Mechanisms of Masonry Columns Reinforced with FRP under Concentric Compressive Load

    OpenAIRE

    Jiří Witzany; Radek Zigler

    2016-01-01

    The strengthening and stabilization of damaged compressed masonry columns with composites based on fabrics of high-strength fibers and epoxy resin, or polymer-modified cement mixtures, belongs to novel, partially non-invasive and reversible progressive methods. The stabilizing and reinforcing effect of these fabrics significantly applies to masonry structures under concentric compressive loading whose failure mechanism is characterized by the appearance and development of vertical tensile cra...

  20. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    KAUST Repository

    Sullivan, J. M.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due to an external airflow, namely a rivulet draining under gravity down a vertical substrate, a rivulet driven by a longitudinal shear stress at its free surface, and a ridge on a horizontal substrate, and find qualitatively similar behaviour for all three problems. We show that, in agreement with previous numerical studies, the free surface profile of an equilibrium rivulet/ridge with pinned contact lines is skewed as the shear stress is increased from zero, and that there is a maximum value of the shear stress beyond which no solution with prescribed semi-width is possible. In practice, one or both of the contact lines will de-pin before this maximum value of the shear stress is reached, and so we consider situations in which the rivulet/ridge de-pins at one or both contact lines. In the case of de-pinning only at the advancing contact line, the rivulet/ridge is flattened and widened as the shear stress is increased from its critical value, and there is a second maximum value of the shear stress beyond which no solution with a prescribed advancing contact angle is possible. In contrast, in the case of de-pinning only at the receding contact line, the rivulet/ridge is thickened and narrowed as the shear stress is increased from its critical value, and there is a solution with a prescribed receding contact angle for all values of the shear stress. In general, in the case of de-pinning at both contact lines there is a critical "yield" value of the shear stress beyond which no equilibrium solution is possible and the rivulet/ridge will evolve unsteadily. In the Appendix, we show that an equilibrium rivulet/ridge with prescribed flux/area is quasi-statically stable to two-dimensional perturbations. © 2012 American Institute of Physics.

  1. Case study: in vivo stress diagnostics by spectroscopic determination of the cutaneous carotenoid antioxidant concentration in midwives depending on shift work

    International Nuclear Information System (INIS)

    Maeter, H; Briese, V; Gerber, B; Darvin, M E; Lademann, J; Olbertz, D M

    2013-01-01

    Laser spectroscopic methods, for instance resonance Raman spectroscopy and reflectance spectroscopy, permit us for the first time to investigate the antioxidative status in human skin non-invasively by measurement of carotenoid concentration. The individual antioxidant concentration of the human skin is determined by the nutritional habits, on the one hand, and by stressors, such as shift work, on the other. Due to the disturbance of the circadian rhythm and melatonin secretion, shift work is associated with, inter alia, insomnia and gastrointestinal disorders. The study at hand was the first to determine the cutaneous antioxidant concentration of midwives using reflectance spectroscopy and to relate the results to shift work. Seven midwives took part in the study. An LED-based compact scanner system was used for non-invasive measurements of carotenoids in human skin. The measuring principle is based on reflection spectroscopy. The study at hand suggests that the cutaneous antioxidative status may be adversely affected by shift work. Despite numerous international strategies of programmes available which invite people to eat more healthily, there are only a few measures aiming at stress reduction and management. In this field the use of reflectance spectroscopic investigation methods could play an essential role in the future. (letter)

  2. The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150

    International Nuclear Information System (INIS)

    Wang, L.; Stuart, M.E.; Lewis, M.A.; Ward, R.S.; Skirvin, D.; Naden, P.S.; Collins, A.L.; Ascott, M.J.

    2016-01-01

    Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses. - Highlights: • An approach to modelling groundwater nitrate at the national scale is presented. • The long time-lag for nitrate in the

  3. The changing trend in nitrate concentrations in major aquifers due to historical nitrate loading from agricultural land across England and Wales from 1925 to 2150

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L., E-mail: lei.wang@bgs.ac.uk [British Geological Survey, Keyworth, Nottingham NG12 5GG (United Kingdom); Stuart, M.E.; Lewis, M.A. [British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Ward, R.S. [British Geological Survey, Keyworth, Nottingham NG12 5GG (United Kingdom); Skirvin, D. [ADAS UK Ltd., Pendeford House, Pendeford Business Park, Wobaston Road, Wolverhampton WV9 5AP (United Kingdom); Naden, P.S. [Centre for Ecology and Hydrology, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Collins, A.L. [Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton EX20 2SB (United Kingdom); Ascott, M.J. [British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB (United Kingdom)

    2016-01-15

    Nitrate is necessary for agricultural productivity, but can cause considerable problems if released into aquatic systems. Agricultural land is the major source of nitrates in UK groundwater. Due to the long time-lag in the groundwater system, it could take decades for leached nitrate from the soil to discharge into freshwaters. However, this nitrate time-lag has rarely been considered in environmental water management. Against this background, this paper presents an approach to modelling groundwater nitrate at the national scale, to simulate the impacts of historical nitrate loading from agricultural land on the evolution of groundwater nitrate concentrations. An additional process-based component was constructed for the saturated zone of significant aquifers in England and Wales. This uses a simple flow model which requires modelled recharge values, together with published aquifer properties and thickness data. A spatially distributed and temporally variable nitrate input function was also introduced. The sensitivity of parameters was analysed using Monte Carlo simulations. The model was calibrated using national nitrate monitoring data. Time series of annual average nitrate concentrations along with annual spatially distributed nitrate concentration maps from 1925 to 2150 were generated for 28 selected aquifer zones. The results show that 16 aquifer zones have an increasing trend in nitrate concentration, while average nitrate concentrations in the remaining 12 are declining. The results are also indicative of the trend in the flux of groundwater nitrate entering rivers through baseflow. The model thus enables the magnitude and timescale of groundwater nitrate response to be factored into source apportionment tools and to be taken into account alongside current planning of land-management options for reducing nitrate losses. - Highlights: • An approach to modelling groundwater nitrate at the national scale is presented. • The long time-lag for nitrate in the

  4. Urinary paraben concentrations among pregnant women and their matching newborn infants of Korea, and the association with oxidative stress biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sungeun; Kim, Sunmi [School of Public Health, Seoul National University (Korea, Republic of); Park, Jeongim [College of Natural Sciences, Soonchunhyang University (Korea, Republic of); Kim, Hae-Joong [College of Medicine, Korea University (Korea, Republic of); Lee, Jeongjae; Choi, Gyuyeon [College of Medicine, Soonchunhyang University (Korea, Republic of); Choi, Sooran; Kim, Sungjoo [College of Medicine, Hallym University (Korea, Republic of); Kim, Su Young [College of Medicine, Jeju National University (Korea, Republic of); Moon, Hyo-Bang [College of Science and Technology, Hanyang University (Korea, Republic of); Kim, Sungkyoon [School of Public Health, Seoul National University (Korea, Republic of); Kho, Young Lim [Department of Health, Environment and Safety, Eulji University (Korea, Republic of); Choi, Kyungho, E-mail: kyungho@snu.ac.kr [School of Public Health, Seoul National University (Korea, Republic of)

    2013-09-01

    Parabens have been used in multiple products including personal care products, pharmaceuticals, and foods for more than 50 years but increasing numbers of studies have raised concerns on their safety. The present study was designed to determine urinary paraben levels among pregnant women and their matching newborn infants (< 48 h after delivery), and the association between paraben levels and stress markers. Pregnant women (n = 46) and their matching newborn infants were recruited from four university hospitals located in Seoul, Ansan and Jeju of Korea, 2011. Parabens including methyl paraben (MP), ethyl paraben (EP), n-propyl paraben (PP), and n-butyl paraben (BP) were measured in the urine using an automatic, high throughput online SPE–LC–MS/MS method. Urinary concentrations were normalized with specific gravity (SG). Free cortisol, malondealdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG) were measured in the urine as stress marker. Urinary MP was detected as the highest, and BP was detected as the lowest paraben in the urine samples of both pregnant women and their infants. Significant correlations between paraben concentrations of maternal and their newborn infant's urine were observed. The levels of urinary parabens among Korean pregnant women are comparable to those reported elsewhere, except for EP which were 4–9 folds higher than pregnant women of other countries. The ratios of infant to maternal urinary paraben concentrations varied between 0.5 and 0.6 for MP and PP, but approximately 10 fold lower for EP. Urinary MP or EP levels were associated with several oxidative stress related biomarkers such as urinary 8-OHdG and MDA, even after the adjustment of relevant covariates such as maternal age, mode of delivery, pre-pregnancy BMI, gestational age and parity. This is the first study that reported the levels of major parabens in the first urine of newborn infants. Further studies are warranted to understand the implications of paraben exposure

  5. Evaluation of ground level concentration of pollutant due to gas flaring by computer simulation: A case study of Niger - Delta area of Nigeria

    Directory of Open Access Journals (Sweden)

    A. S. ABDULKAREEM

    2005-01-01

    Full Text Available The disposal of associated gases through flaring has been a major problem for the Nigerian oil and gas industries and most of theses gases are flared due to the lack of commercial out lets. The resultant effects of gas flaring are the damaging effect of the environment due to acid rain formation, green house effect, global warming and ozone depletion.This writes up is aimed at evaluating ground level concentration of CO2, SO2, NO2 and total hydrocarbon (THC, which are product of gas flared in oil producing areas. Volumes of gas flared at different flow station were collected as well as geometrical parameters. The results of simulation of model developed based on the principles of gaseous dispersion by Gaussian showed a good agreement with dispersion pattern.The results showed that the dispersion pattern of pollutants at ground level depends on the volume of gas flared, wind speed, velocity of discharge and nearness to the source of flaring. The results shows that continuous gas flaring irrespective of the quantity deposited in the immediate environment will in long run lead to change in the physicochemical properties of soil.

  6. Analysis of residual stresses due to roll-expansion process: Finite element computation and validation by experimental tests

    International Nuclear Information System (INIS)

    Aufaure, M.; Boudot, R.; Zacharie, G.; Proix, J.M.

    1987-01-01

    The steam generator heat exchangers of pressurized water reactors are made of U-shaped tubes, both ends of them being fixed to a plate by roll-expansion. This process consists in increasing the tube section by means of a rotating tool in order to apply its outer side to the surface of the hole through the plate. As reported by de Keroulas (1986), in service cracks appeared on these tubes in the transition from expanded to nonexpanded portions. So we developed a program to compute residual stresses at the surface of the tubes, which caused their cracking, and to endeavour to lower their level by acting on some parameters. This program was validated by experimental tests. (orig.)

  7. A pilot study: Horticulture-related activities significantly reduce stress levels and salivary cortisol concentration of maladjusted elementary school children.

    Science.gov (United States)

    Lee, Min Jung; Oh, Wook; Jang, Ja Soon; Lee, Ju Young

    2018-04-01

    The effects of three horticulture-related activities (HRAs), including floral arranging, planting, and flower pressing were compared to see if they influenced changes on a stress scale and on salivary cortisol concentrations (SCC) in maladjusted elementary school children. Twenty maladjusted elementary school children were randomly assigned either to an experimental or control group. The control group carried out individual favorite indoor activities under the supervision of a teacher. Simultaneously, the ten children in the experimental group participated in a HRA program consisting of flower arrangement (FA), planting (P), and flower pressing (PF) activities, in which the other ten children in the control group did not take part. During nine sessions, the activities were completed as follows: FA-FA-FA, P-P-P, and PF-PF-PF; each session lasted 40 min and took place once a week. For the quantitative analysis of salivary cortisol, saliva was collected from the experimental group one week before the HRAs and immediately after the activities for 9 consecutive weeks at the same time each session. In the experimental group, stress scores of interpersonal relationship, school life, personal problems, and home life decreased after the HRAs by 1.3, 1.8, 4.2, and 1.3 points, respectively. In particular, the stress score of school life was significantly reduced (P < 0.01). In addition, from the investigation of the SCCs for the children before and after repeating HRAs three times, it was found that flower arrangement, planting, and flower pressing activities reduced the SCCs by ≥37% compared to the SCCs prior to taking part in the HRAs. These results indicate that HRAs are associated with a reduction in the stress levels of maladjusted elementary school children. Copyright © 2018. Published by Elsevier Ltd.

  8. OCO-2 chlorophyll fluorescence tracks late-summer photosynthesis decrease due to water stress at Missouri Ozark site

    Science.gov (United States)

    He, L.; Frankenberg, C.; Wood, J. D.; Sun, Y.

    2017-12-01

    Accurate estimate of the photosynthetic uptake of CO2, denoted gross primary productivity (GPP), is important to understand and quantify the carbon cycles at regional to global scales, and has implications in crop and forest management. Solar-induced chlorophyll fluorescence (SIF) retrieved from space was found to be strongly correlated with GPP and is now being used as a potential new technique to estimate photosynthetic rates at large scale. We selected the Missouri Ozark Site as a test bed, a well-characterized Eddy Covariance site in deciduous broadleaf forests, to explore the relationships of vegetation indices (VIs) and SIF with GPP and their response to environmental conditions. We find that both GPP fluxes and OCO-2 SIF decreased in late summer at the Ozark Site, directly related to water stress, evidenced by a progressive decrease in soil moisture and concomitant changer in leaf water potential. However, VIs (both NDVI and EVI) stayed stable during the same period. With a focus on this wet-dry transition period, we analyze driving factors of changes in GPP and SIF, which appear to be linearly related even in this period with little reflectance changes. We also used the Soil Canopy Observation, Photochemistry and Energy fluxes (SCOPE) model to compare observations of SIF and GPP against measurement. The primary motivation is not only to quantify the expected correlations between the GPP and SIF but also to validate performance of SCOPE in reproducing such correlations, which have not been tested against independent observations. This study clearly underlines the potential of SIF measurements to study moderate water stress and its impact on photosynthesis.

  9. Blubber cortisol: a potential tool for assessing stress response in free-ranging dolphins without effects due to sampling.

    Directory of Open Access Journals (Sweden)

    Nicholas M Kellar

    Full Text Available When paired with dart biopsying, quantifying cortisol in blubber tissue may provide an index of relative stress levels (i.e., activation of the hypothalamus-pituitary-adrenal axis in free-ranging cetacean populations while minimizing the effects of the act of sampling. To validate this approach, cortisol was extracted from blubber samples collected from beach-stranded and bycaught short-beaked common dolphins using a modified blubber steroid isolation technique and measured via commercially available enzyme immunoassays. The measurements exhibited appropriate quality characteristics when analyzed via a bootstraped stepwise parallelism analysis (observed/expected = 1.03, 95%CI: 99.6 - 1.08 and showed no evidence of matrix interference with increasing sample size across typical biopsy tissue masses (75-150 mg; r(2 = 0.012, p = 0.78, slope = 0.022 ng(cortisol deviation/ul(tissue extract added. The relationships between blubber cortisol and eight potential cofactors namely, 1 fatality type (e.g., stranded or bycaught, 2 specimen condition (state of decomposition, 3 total body length, 4 sex, 5 sexual maturity state, 6 pregnancy status, 7 lactation state, and 8 adrenal mass, were assessed using a Bayesian generalized linear model averaging technique. Fatality type was the only factor correlated with blubber cortisol, and the magnitude of the effect size was substantial: beach-stranded individuals had on average 6.1-fold higher cortisol levels than those of bycaught individuals. Because of the difference in conditions surrounding these two fatality types, we interpret this relationship as evidence that blubber cortisol is indicative of stress response. We found no evidence of seasonal variation or a relationship between cortisol and the remaining cofactors.

  10. Stress rotations due to the M6.5 foreshock and M7.3 main shock in the 2016 Kumamoto, SW Japan, earthquake sequence

    Science.gov (United States)

    Yoshida, Keisuke; Hasegawa, Akira; Saito, Tatsuhiko; Asano, Youichi; Tanaka, Sachiko; Sawazaki, Kaoru; Urata, Yumi; Fukuyama, Eiichi

    2016-10-01

    A shallow M7.3 event with a M6.5 foreshock occurred along the Futagawa-Hinagu fault zone in Kyushu, SW Japan. We investigated the spatiotemporal variation of the stress orientations in and around the source area of this 2016 Kumamoto earthquake sequence by inverting 1218 focal mechanisms. The results show that the σ3 axis in the vicinity of the fault plane significantly rotated counterclockwise after the M6.5 foreshock and rotated clockwise after the M7.3 main shock in the Hinagu fault segment. This observation indicates that a significant portion of the shear stress was released both by the M6.5 foreshock and M7.3 main shock. It is estimated that the stress release by the M6.5 foreshock occurred in the shallower part of the Hinagu fault segment, which brought the stress concentration in its deeper part. This might have caused the M7.3 main shock rupture mainly along the deeper part of the Hinagu fault segment after 28 h.

  11. Induction of apoptosis by zerumbone isolated from Zingiber zerumbet (L.) Smith in protozoan parasite Leishmania donovani due to oxidative stress

    OpenAIRE

    Mukherjee, Debarati; Singh, Chingakham Brajakishor; Dey, Somaditya; Mandal, Supratim; Ghosh, Joydip; Mallick, Suvadip; Hussain, Aabid; Swapana, Ningombam; Ross, Samir Anis; Pal, Chiranjib

    2016-01-01

    Abstract In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmaniainfection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zeru...

  12. Effects of dietary selenium on tissue concentrations,pathology, oxidative stress, and immune function in common eiders (Somateria mollissima)

    Science.gov (United States)

    Franson, J. Christian; Hoffman, David; Wells-Berlin, Alicia M.; Perry, Matthew C.; Shearn-Bochsler, Valerie I.; Finley, Daniel L.; Flint, Paul L.; Hollmén, Tuula E.

    2007-01-01

    Common eiders (Somateria mollissima) were fed added Se (as L-selenomethionine) in concentrations increasing from 10 to 80 ppm in a pilot study (Study 1) or 20 (low exposure) and up to 60 (high exposure) ppm Se in Study 2. Body weights of Study 1 ducks and high-exposure ducks in Study 2 declined rapidly. Mean concentrations of Se in blood reached 32.4 ppm wet weight in Study 1 and 17.5 ppm wet weight in high-exposure birds in Study 2. Mean Se concentrations in liver ranged from 351 (low exposure, Study 2) to 1252 ppm dry weight (Study 1). Oxidative stress was evidenced by Se-associated effects on glutathione metabolism. As Se concentrations in liver increased, Se-dependent glutathione peroxidase activity, glutathione reductase activity, oxidized glutathione levels, and the ratio of hepatic oxidized to reduced glutathione increased. In Study 2, the T-cell-mediated immune response was adversely affected in high-exposure eiders, but ducks in the low-exposure group exhibited evidence of an enhanced antibody-mediated immune response. Gross lesions in high-exposure ducks included emaciation, absence of thymus, and loss of nails from digits. Histologic lesions included severe depletion of lymphoid organs, hepatopathy, and necrosis of feather pulp and feather epithelium. Field studies showed that apparently healthy sea ducks generally have higher levels of Se in liver than healthy fresh-water birds, but lower than concentrations found in our study. Data indicate that common eiders and probably other sea ducks possess a higher threshold, or adverse effect level, for Se in tissues than fresh-water species. However, common eiders developed signs of Se toxicity similar to those seen in fresh-water birds.

  13. Effects of Stress Concentration on the Mechanical Properties of Carbon Fiber Reinforced Plastic

    Directory of Open Access Journals (Sweden)

    Ryo Naito

    2017-03-01

    Full Text Available Mechanical properties of conventional CFRP plates with small holes were investigated systematically. Those artificial holes are considered to be rivet connection between CFRP and other materials. The machining holes were employed with different number (n=0-5 and different mode, e.g., parallel (Sample A, 45 degree (Sample B and perpendicular (Sample C against the loading direction. To understand the mechanical properties of the CFRP plates clearly, tensile tests and failure analysis were conducted experimentally. Excellent mechanical properties were obtained for Sample A, compared to the other ones. This is due to the different size of the cross-section area in the specimen. With increasing the number of rivet hole, the mechanical properties were lineally decreasing. Such mechanical properties were analyzed by direct observation using a high speed camera, i.e., in-situ measurement of deformation during the tensile loading was carried

  14. Salivary Concentration of Oxidative Stress Biomarkers in a Group of Patients with Peri-Implantitis: A Transversal Study.

    Science.gov (United States)

    Sánchez-Siles, Mariano; Lucas-Azorin, Javier; Salazar-Sánchez, Noemi; Carbonell-Meseguer, Luis; Camacho-Alonso, Fabio

    2016-10-01

    The purpose of this study was to know if peri-implantitis causes an increase in the total salivary concentration of oxidative stress markers. Seventy patients, 28 men and 42 women, 60 of them with dental implants, 30 of which had peri-implantitis and 30 were healthy. The remaining 10 were the control group: healthy subjects without implants. The average number of implants per patient was 4.70 ± 2.29 in the peri-implantitis group and 2 70 ± 2.11 in the control group. Periodontal/peri-implant variables were assessed, including bleeding index, gingival index, clinical attachment level, probing depth, presence of pockets larger than 4 and 6 mm, pain to percussion, suppuration, gingival hyperplasia or granuloma, crestal bone loss (both mesially and distally), evaluated through periapical radiography. Saliva samples from the 70 subjects were collected for measurement of malondialdehyde high performance liquid chromatography (HPLC) and myeloperoxidase (enzyme-linked immunosorbent assay analysis) concentrations. Implants affected with peri-implantitis had an average follow-up of 26.40 ± 7.97 months. 4.12% of implants with peri-implantitis had a painful response to percussion. 2.06% showed suppuration; 25.77% had granuloma. The mean crestal bone loss in implants wtih peri-implantitis was 3.78 ± 1.17 mm. Total salivary malondialdehyde concentration in the peri-implantitis group (0.52 ± 0.37 μM/l) was slightly higher than that in the group with healthy implants (0.40 ± 0.16 μM/l) and also slightly higher than that in the group of healthy patients without implants (0.41 ± 0.79 μM/l), although the difference was not statistically significant, p value = .442. Myeloperoxidase concentration was slightly higher in the peri-implantitis group (12.32 ± 2.17 ng/ml) than in the group with healthy implants (11.54 ± 2.80 ng/ml) and the group of healthy patients without implants (11.86 ± 2.67 ng/ml), without

  15. Glucose concentration and blood acid-basis status in high-yielding dairy cows during heat stress

    Directory of Open Access Journals (Sweden)

    Vujanac Ivan

    2011-01-01

    Full Text Available The objective of this work was to examine the effect of heat stress on glucose and pH values in blood of high-yielding dairy cows in the early stage of lactation, as well as to determine whether the changes in these parameters are interdependent under such conditions. An experiment was performed on high-yielding dairy cows during the summer and the spring periods. Forty cows were selected, twenty each for the two periods under investigation. In the course of the experiment, the temperature humidity index (THI was determined for the entire period of investigations, and then also the average daily THI, nightmorning THI (average value of hourly THI measured from 22h on the previous day until 10h of the current day, as well as the day-night THI (average value of hourly THI measured during the period from 10h to 22h of the current day. The pH and glucose concentration were determined in blood samples taken in the morning and afternoon of days 30, 60, and 90 of lactation during the spring and summer periods of the investigations. Based on the results for the THI, it was established that the animals were not exposed to the effect of extreme heat stress during the spring period of investigations, while they were periodically exposed to moderate but also extreme heat stress during the summer, in particular in the afternoon hours. It can be concluded from the results obtained for the blood pH that the cows were in respiratory alkalosis during the summer in the morning and afternoon hours on day 30, in the afternoon hours of days 60 and 90 of lactation, as well as in the afternoon on day 90 of lactation during the spring period of investigations. During the summer period, there were no statistically significant differences between the pH value determined in the morning and afternoon hours on day 30 of lactation, while the pH value was significantly higher in the afternoon hours than in the morning hours on days 60 and 90 of lactation. There were no

  16. Investigation of an Axial Fan—Blade Stress and Vibration Due to Aerodynamic Pressure Field and Centrifugal Effects

    Science.gov (United States)

    Xu, Cheng; Amano, Ryoichi Samuel; Lee, Eng Kwong

    A 1.829m (6ft) diameter industrial large flow-rate axial fan operated at 1770rpm was studied experimentally in laboratory conditions. The flow characteristics on the fan blade surfaces were investigated by measuring the pressure distributions on the blade suction and pressure surfaces and the results were discussed by comparing with analytical formulations and CFD. Flow visualizations were also performed to validate the flow characteristics near the blade surface and it was demonstrated that the flow characteristics near the fan blade surface were dominated by the centrifugal force of the fan rotation which resulted in strong three-dimensional flows. The time-dependent pressure measurement showed that the pressure oscillations on the fan blade were significantly dominated by vortex shedding from the fan blades. It was further demonstrated that the pressure distributions during the fan start-up were highly unsteady, and the main frequency variation of the static pressure was much smaller than the fan rotational frequency. The time-dependent pressure measurement when the fan operated at a constant speed showed that the magnitude of the blade pressure variation with time and the main variation frequency was much smaller than the fan rotational frequency. The pressure variations that were related to the vortex shedding were slightly smaller than the fan rotational frequency. The strain gages were used to measure the blade stress and the results were compared with FEA results.

  17. Escalating heat-stress mortality risk due to global warming in the Middle East and North Africa (MENA).

    Science.gov (United States)

    Ahmadalipour, Ali; Moradkhani, Hamid

    2018-08-01

    Climate change will substantially exacerbate extreme temperature and heatwaves. The impacts will be more intense across the Middle East and North Africa (MENA), a region mostly characterized by hot and arid climate, already intolerable for human beings in many parts. In this study, daily climate data from 17 fine-resolution Regional Climate Models (RCMs) are acquired to calculate wet-bulb temperature and investigate the mortality risk for people aged over 65 years caused by excessive heat stress across the MENA region. Spatially adaptive temperature thresholds are implemented for quantifying the mortality risk, and the analysis is conducted for the historical period of 1951-2005 and two future scenarios of RCP4.5 and RCP8.5 during the 2006-2100 period. Results show that the mortality risk will increase in distant future to 8-20 times higher than that of the historical period if no climate change mitigation is implemented. The coastal regions of the Red sea, Persian Gulf, and Mediterranean Sea indicate substantial increase in mortality risk. Nonetheless, the risk ratio will be limited to 3-7 times if global warming is limited to 2 °C. Climate change planning and adaptation is imperative for mitigating heat-related mortality risk across the region. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Stress corrosion cracking of X80 pipeline steel exposed to high pH solutions with different concentrations of bicarbonate

    Science.gov (United States)

    Fan, Lin; Du, Cui-wei; Liu, Zhi-yong; Li, Xiao-gang

    2013-07-01

    Susceptibilities to stress corrosion cracking (SCC) of X80 pipeline steel in high pH solutions with various concentrations of HCO{3/-} at a passive potential of -0.2 V vs. SCE were investigated by slow strain rate tensile (SSRT) test. The SCC mechanism and the effect of HCO{3/-} were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhanced susceptibility to SCC with the concentration of HCO{3/-} increasing from 0.15 to 1.00 mol/L, and the susceptibility can be evaluated in terms of current density at -0.2 V vs. SCE. The SCC behavior is controlled by the dissolution-based mechanism in these circumstances. Increasing the concentration of HCO{3/-} not only increases the risk of rupture of passive films but also promotes the anodic dissolution of crack tips. Besides, little susceptibility to SCC is found in dilute solution containing 0.05 mol/L HCO{3/-} for X80 steel. This can be attributed to the inhibited repassivation of passive films, manifesting as a more intensive dissolution in the non-crack tip areas than at the crack tips.

  19. Live changes in muscle glycogen concentration of steers due to feeding and fasting as determined through serial biopsies of the Longissimus dorsi muscle

    Directory of Open Access Journals (Sweden)

    Ariel Apaoblaza

    2014-03-01

    Full Text Available Insufficient glycogen content in bovine muscle at slaughter produces meat with high final pH (> 5.8 which is undesirable. The objective of this study was to determine through biopsies the live changes in muscle glycogen concentration (MGC of housed steers fed on hay or hay plus energy concentrate for 30 d and then determine the effect of food deprivation (fasting for 24 h on the same variable. Ten steers of similar age, weight, and phenotypic characteristics were housed in individual pens and randomly assigned to two feeding treatments: ad libitum hay only (H, n = 5 and ad libitum hay plus flaked corn (Zea mays L. (HC, n = 5. Biopsies (B were taken from the Longissimus dorsi muscle at four occasions: the day before the start of experiment (B0, after 15 d (Bl, after 30 d (B2, and fasted for 24 h after B2 (B3. Before each biopsy, steers were sedated with xylazine (0.03 mL kg-1 and lidocaine was applied locally; samples were frozen in liquid nitrogen to determine MGC. Results showed a significant (P H and also of time (B2 > Bl on MGC; the decrease in MGC of steers due to fasting (B2 vs. B3 was not significant (P > 0.05. It was concluded that muscle biopsies allowed to detect a difference in the increase of MGC in steers fed an energy supplementation compared to steers fed hay only, and that fasting for 24 h tended to reduce MGC in both groups.

  20. Structural and ecophysiological alterations of the water hyacinth [Eichhornia crassipes (Mart. Solms] due to anthropogenic stress in Brazilian rivers

    Directory of Open Access Journals (Sweden)

    Angela Pierre Vitória

    2011-10-01

    Full Text Available In this work, the structural and ecophysiological alterations (chlorophyll a fluorescence and photosynthetic pigments, and quantification of Cr, Pb and Zn in the leaf limb, petiole and younger and older roots of water hyacinth from the lower, medium and upper Paraíba do Sul river (PSR and Imbé river were evaluated. The plants from the medium and upper PSR (more industrialized and populated regions exhibited lower turgid cell in the root cortex, less root hairs and leaf epidermis, chloroplasts with plastoglobules and increased stroma volume. Higher concentrations of metals were observed in the younger and older roots from the medium PSR plants. The results suggested that the plants from more anthropized regions were able to maintain the maximum quantum yield (Fv/Fm which was a result from the metabolic fitting, increasing the non-photochemical quenching, reducing total chlorophyll/carotenoids and leading to the structural modifications.

  1. Cuticular characteristics in the detection of plant stress due to air pollution - new problems in the use of these cuticular characteristics

    International Nuclear Information System (INIS)

    Garrec, J.P.

    1994-01-01

    The foliar surface, and particularly the cuticle, is the first zone of impact of air pollutants on leaves. At the level of the cuticle, it is mainly studies on the modifications of the physico-chemical properties of the waxes that allow us to detect and estimate plant stress. However, during recent years, with modifications in the nature and level of air pollution (decrease of primary pollutants: SO 2 , HF; increase of secondary pollutants: O 2 , acid deposits; increase of nitrogen deposits; increase of organic micropollutants; appearence of global environmental problems: CO 2 , climatic change), the physiological impact on plants and in particular on the cuticle is different. For this reason, new problems have appeared and use of cuticular characteristics in the detection of plant stress due to air pollutants has recently evolved. Some examples are given, but much remains to be done to understand the effects on the cuticle of these new modifications of the atmospheric environment of plants. (orig.)

  2. Starting solutions for the flow of second grade fluids in a rectangular channel due to an oscillating shear stress

    Science.gov (United States)

    Vieru, Dumitru; Fetecau, Corina; Rana, Mehwish

    2012-05-01

    The unsteady motion of a second grade fluid between two parallel side walls perpendicular to a plate is studied by means of the Fourier sine and cosine transforms. Initially, the fluid is at rest and at time t = 0+, the plate applies an oscillating shear to the fluid. The solutions that have been obtained, presented under integral and series form and written as a sum between steady time-periodic and transient solutions can be easily reduced to the similar solutions for Newtonian fluids performing the same motion. They describe the motion of the fluid some time after its initiation. After that time, when the transient solutions disappear, the motion of the fluid is described by the steady time-periodic solutions that are independent of the initial conditions. In the absence of side walls, more exactly when the distance between walls tends to infinity, all solutions reduce to those corresponding to the motion over an infinite plate. As it was to be expected, the steady time-periodic solutions corresponding to sine and cosine oscillations of the shear stress on the boundary differ by a phase shift. Finally, the influence of side walls on the fluid motion, the required time to reach the steady periodic flow, as well as the distance between walls for which the velocity of the fluid in the middle of the channel is unaffected by their presence are established by numerical calculus and graphical illustrations. As expected, the time needed to reach the steady periodic flows is lower in the presence of side walls. It is lower for Newtonian fluids in comparison with second grade fluids and greater for sine oscillations in comparison to the cosine oscillations of the boundary shear.

  3. [Effects of short-term elevated CO2 concentration and drought stress on the rhizosphere effects of soil carbon, nitrogen and microbes of Bothriochloa ischaemum.

    Science.gov (United States)

    Xiao, Lie; Liu, Guo Bin; Li, Peng; Xue, Sha

    2017-10-01

    A water control pot experiment was conducted in climate controlled chambers to study soil carbon, nitrogen and microbial community structure and their rhizosphere effects in the rhizosphere and non rhizosphere soil of Bothriochloa ischaemum at elevated CO2 concentrations (800 μmol·mol -1 ) under three water regimes, i.e., well watered (75%-80% of field capacity, FC), moderate drought stress (55%-60% of FC), and severe drought stress (35%-40% of FC). The results showed that elevated CO2 concentration and drought stress did not have significant impacts on the content of soil organic carbon, total nitrogen or dissolved organic carbon (DOC) in the rhizosphere and bulk soils or their rhizosphere effects. Elevated CO2 concentration significantly decreased dissolved organic nitrogen (DON) content in the rhizosphere soil under moderate drought stress, increased DOC/DON, and significantly increased the negative rhizosphere effect of DON and positive rhizosphere effect of DOC/DON. Drought stress and elevated CO2 concentration did not have significant impacts on the rhizosphere effect of total and bacterial phospholipid fatty acids (PLFA). Drought stress under elevated CO2 concentration significantly increased the G + /G - PLFA in the rhizosphere soil and decreased the G + /G - PLFA in the bulk soil, so its rhizosphere effect significantly increased, indicating that the soil microbial community changed from chemoautotroph microbes to heterotrophic microbes.

  4. Induction of apoptosis by zerumbone isolated from Zingiber zerumbet (L. Smith in protozoan parasite Leishmania donovani due to oxidative stress

    Directory of Open Access Journals (Sweden)

    Debarati Mukherjee

    2016-01-01

    Full Text Available In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmania infection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zerumbet (L. Smith, has been studied for its pharmacological potential as antiulcer, antioxidant, anticancer, and antimicrobial. In this study, we have shown that zerumbone could induce ROS mediated apoptosis in Leishmania donovani promastigotes and also found effective in reducing intracellular amastigotes in infected-macrophages. We emphasized the potential of zerumbone to be employed in the development of new therapeutic drugs against L. donovani infection and provided the basis for future research on the application of transitional medicinal plants.

  5. Endogenous Ethylene Concentration Is Not a Major Determinant of Fruit Abscission in Heat-Stressed Cotton (Gossypium hirsutum L.

    Directory of Open Access Journals (Sweden)

    Ullah Najeeb

    2017-09-01

    Full Text Available We investigated the role of ethylene in the response of cotton to high temperature using cotton genotypes with genetically interrupted ethylene metabolism. In the first experiment, Sicot 71BRF and 5B (a lintless variant with compromised ethylene metabolism were exposed to 45°C, either by instantaneous heat shock or by ramping temperatures by 3°C daily for 1 week. One day prior to the start of heat treatment, half the plants were sprayed with 0.8 mM of the ethylene synthesis inhibitor, aminoethoxyvinylglycine (AVG. In a subsequent experiment, Sicot 71BRF and a putatively heat-tolerant line, CIM 448, were exposed to 36 or 45°C for 1 week, and half the plants were sprayed with 20 μM of the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, (ACC. High temperature exposure of plants in both experiments was performed at the peak reproductive phase (65–68 days after sowing. Elevated temperature (heat shock or ramping to 45°C significantly reduced production and retention of fruits in all cotton lines used in this study. At the termination of heat treatment, cotton plants exposed to 45°C had at least 50% fewer fruits than plants under optimum temperature in all three genotypes, while plants at 36°C remained unaffected. Heat-stressed plants continued producing new squares (fruiting buds after termination of heat stress but these squares did not turn into cotton bolls due to pollen infertility. In vitro inhibition of pollen germination by high temperatures supported this observation. Leaf photosynthesis (Pn of heat-stressed plants (45°C measured at the end of heat treatments remained significantly inhibited, despite an increased leaf stomatal conductance (gs, suggesting that high temperature impairs Pn independently of stomatal behavior. Metabolic injury was supported by high relative cellular injury and low photosystem II yield of the heat-stressed plants, indicating that high temperature impaired photosynthetic electron transport. Both

  6. Derivation of Elastic Stress Concentration Factor Equations for Debris Fretting Flaws in Pressure Tubes of Pressurized Heavy Water Reactors

    International Nuclear Information System (INIS)

    Kim, Jong Sung; Oh, Young Jin

    2014-01-01

    If volumetric flaws such as bearing pad fretting flaws and debris fretting flaws are detected in the pressure tubes of pressurized heavy water reactors during in-service inspection, the initiation of fatigue cracks and delayed hydrogen cracking from the detected volumetric flaws shall be assessed by using elastic stress concentration factors in accordance with CSA N285.8-05. The CSA N285.8-05 presents only an approximate formula based on linear elastic fracture mechanics for the debris fretting flaw. In this study, an engineering formula considering the geometric characteristics of the debris fretting flaw in detail was derived using two-dimensional finite element analysis and Kinectrics, Inc.'s engineering procedure with slight modifications. Comparing the application results obtained using the derived formula with the three-dimensional finite element analysis results, it is found that the results obtained using the derived formula agree well with the results of the finite element analysis

  7. Stress

    Science.gov (United States)

    ... taking care of an aging parent. With mental stress, the body pumps out hormones to no avail. Neither fighting ... with type 1 diabetes. This difference makes sense. Stress blocks the body from releasing insulin in people with type 2 ...

  8. Simulation of the spatial stresses due to territorial land development on Yellow River Delta Nature Reserve using a GIS-based assessment model.

    Science.gov (United States)

    Zhang, Baolei; Zhang, Qiaoyun; Feng, Qingyu; Cui, Bohao; Zhang, Shumin

    2017-07-01

    This study aimed at assessing the stresses from land development in or around Yellow River Delta Nature Reserve (YRDNR) and identifying the impacted areas. Major land development types (reservoirs, pond, aquafarm, salt pan, road, residential land, industry land, farming land, and fishing land) in or around the YRDNR from 1995 to 2014 were identified using spatial data sets derived from remote sensing imageries. The spatial stresses were simulated by considering disturbance due to land development activities and accessibility of disturbance using a geographic information system based model. The stresses were then used to identify the impacted area by land development (IALD). The results indicated that main increasing land development types in the study area from 1995 to 2014 were salt pan and construction land. The 98.2% of expanded land development area and 93.7% of increased pump number showed a good control of reserve function zone on land development spread. The spatial stress values and percentages of IALD increased from 1995 to 2014, and IALD percentage exceeded 50% for both parts of YRDNR in 2014. The results of this study also provided the information that detailed planning of the YRDNR (2014-2020) could decrease the spatial stress and IALD percentage of the whole YRDNR on the condition that the area of land development activities increased by 24.4 km 2 from 2014 to 2020. Effective measures should be taken to protect such areas from being further disturbed in order to achieve the goal of a more effective conservation of the YRDNR, and attention should be paid to the disordered land development activities in or around the natural reserves.

  9. Risk markers of all-cause and diagnosis-specific disability pension--a prospective cohort study of individuals sickness absent due to stress-related mental disorders.

    Science.gov (United States)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2014-08-07

    Stress-related mental disorders rank among the leading causes of sickness absence in several European countries. The aim of this study was to investigate predictors of all-cause and diagnosis-specific disability pension in sickness absentees with stress-related mental disorders. A cohort of 36304 non-retired individuals aged 16-64 years at 31.12.2004 with at-least one sickness absence spell due to stress-related mental disorders (SRMD) initiated in 2005 in Sweden was followed-up with regard to disability pension (2006-2010) by linkage of registers. Uni- and multivariate Hazard ratios (HR) with 95% Confidence Intervals, CI, were estimated using Cox regression for several risk markers. During the follow-up period, 2735 individuals (7.5%) were granted a disability pension, predominantly due to mental diagnoses (n = 2004, 73.3%). In the multivariate analyses, female sex, age exceeding 35 years, low educational level, being born in a country outside EU25 and Northern Europe, residing outside big cities, living alone, having had a long duration of the first spell due to SRMD (>90 days); mental disorders necessitating frequent specialised health care as well as comorbid somatic disorders were found to be predictive of granting disability pension. Some different patterns emerged for risk factors related to diagnosis-specific disability pension and for younger and older individuals. Several predictors could be identified as risk markers for disability pension. The variation in the effect of risk markers with regard to age and diagnosis of disability pension speaks in favour of the importance of a person-centered approach in treatment and rehabilitation.

  10. Evaluation of stress distribution due to shearing in non-oriented electrical steel by using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Yoshiaki Zaizen

    2016-05-01

    Full Text Available The influence of the shearing process on the iron loss of non-oriented electrical steels with grain sizes of 10 μm-150 μm was investigated. The deterioration ratio of iron loss was clearly smaller in sample with small grain sizes. The droop height, reflecting the amount of plastic deformation, displayed a good relationship with the deterioration of iron loss under the effect of the material grain size. To clarify the strain distribution around the sheared edge, the elastic strain in a sheet sample with the thickness of 0.30 mm and grain size of 10 μm was evaluated by using synchrotron radiation. The width of the region of elastic strain due to shearing was two or three times of the material thickness. The results of the plastic strain distribution obtained by the measurements were then used to estimate the iron loss deterioration rate in 5 mm width sheared samples. The estimated loss deteriotation coincided with the actual measured iron loss.

  11. Evaluation of stress distribution due to shearing in non-oriented electrical steel by using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaizen, Yoshiaki, E-mail: y-zaizen@jfe-steel.co.jp; Omura, Takeshi; Senda, Kunihiro [Steel Research Laboratory, JFE Steel Corporation, Kawasakidori 1,Mizushima, Kurashiki,712-8511 (Japan); Fukumura, Masaru [Steel Research Laboratory, JFE Steel Corporation, Kawasaki, Kanagawa 210-0855 (Japan); Toda, Hiroaki [Steel Business Planning Dept, JFE Steel Corporation, Tokyo 100-0011 (Japan)

    2016-05-15

    The influence of the shearing process on the iron loss of non-oriented electrical steels with grain sizes of 10 μm-150 μm was investigated. The deterioration ratio of iron loss was clearly smaller in sample with small grain sizes. The droop height, reflecting the amount of plastic deformation, displayed a good relationship with the deterioration of iron loss under the effect of the material grain size. To clarify the strain distribution around the sheared edge, the elastic strain in a sheet sample with the thickness of 0.30 mm and grain size of 10 μm was evaluated by using synchrotron radiation. The width of the region of elastic strain due to shearing was two or three times of the material thickness. The results of the plastic strain distribution obtained by the measurements were then used to estimate the iron loss deterioration rate in 5 mm width sheared samples. The estimated loss deteriotation coincided with the actual measured iron loss.

  12. Effects of Gibberellic Acid and Nitrogen on Some Physiology Parameters and Micronutrients Concentration in Pistachio under Salt Stress

    Directory of Open Access Journals (Sweden)

    vahid mozafari

    2017-02-01

    /63, Tissue (Sandy loam, electrical conductivity (ECe (1 dS m-1, Silt (23.1%, Clay (5.5%, Organic matter (0.5%, Olsen phosphorus (P (5.35 mg kg-1, Ammonium acetate-extractable K (100 mg kg-1 were determined. Nitrogen treatments 3 weeks after planting, dissolved in irrigation water was added to pots. Salinity, after the establishment of the plant (5 weeks after planting, divided into two equal parts and one-week interval dissolved with irrigation water was added to the pot. as well acid gibberellic treatments, as spray after salt treatment was applied at three times and at intervals of one week. Results and discussion: The results showed that the salinity content of carotenoid and Chlorophyll fluorescence parameters significantly reduced but with increasing acid gibberellic and nitrogen application, mentioned parameters were significantly increased, compared to controls. The ability of photosynthesis improved and increased productivity. Mozafari et al studied the pistachio, reported that with increasing salinity from zero to 150 and 300 mM NaCl, carotenoids decreased more than 16% and 22% compared to control respectively. Carotenoids play a most important role in light, protecting plants against stress condition. Salinity application increased leaf proline, but with application of 150 mg nitrogen and 500 mg per liter foliar application of acid gibberellics, this parameter increased by 55 and 26 percent, respectively. Also, combined use of these two treatments increased proline content by 79 percent compared to control. The researchers stated that the increasing gibberellin concentration caused leaf proline increased, so spraying 100 and 200 mg per liter gibberellin significantly increased leaf proline compared with the non-application of gibberellin. The results also showed with increasing salinity increased iron, manganese and zinc concentrations shoots and roots and decreased copper concentrations, but using 150 mg of nitrogen and acid gibberellic consumption concentrations

  13. Molecular oxidative stress markers in olive ridley turtles (Lepidochelys olivacea) and their relation to metal concentrations in wild populations.

    Science.gov (United States)

    Cortés-Gómez, Adriana A; Morcillo, Patricia; Guardiola, Francisco A; Espinosa, Cristobal; Esteban, María A; Cuesta, Alberto; Girondot, Marc; Romero, Diego

    2018-02-01

    Due to their longevity and extensive migration areas, marine turtles are able to accumulate diverse contaminants over many years and as a consequence they represent an interesting bioindicator species for marine ecosystem pollution. Metals provoke toxicological effects in many aquatic animal species, but marine turtles have been under-investigated in this area. Thus, we have determined the presence of certain inorganic elements (As, Cd, Cu, Ni, Pb, Se and Zn) in olive ridley turtles (Lepidochelys olivacea) and related them to metallothionein (MT), superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) transcription and/or enzymatic activities. Gene expression of sod, cat and gr was found to be higher in blood than liver or kidney but most of the significant relationships were found in liver, not only for gene expression but also for enzyme activities. This must be related to the role the liver has as the first filter organ. Several positive relationships of sod, cat and gr gene expression in the different tissues were found in this population, as well as very high Cd concentrations. This could mean that these turtles are adapting to the metals-production of ROS and damage through a high transcription of these antioxidants. Multiple positive relationships with GR seem to be part of its compensatory effect due to the decrease of SOD production against the high and chronic exposure to certain xenobiotics. CAT, on the other hand, seems not to be used much, and glutathione detoxification of H 2 O 2 may be more important in this species. Finally, despite the very high Cd concentrations found in this population, no significant relationship was found in any tissue with metallothionein gene expression. These results, along with very high Cd concentrations and a negative relationship with Cu, lead us to consider some kind of disruption in mt gene expression in these turtles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Microparticle content of platelet concentrates is predicted by donor microparticles and is altered by production methods and stress.

    Science.gov (United States)

    Maurer-Spurej, Elisabeth; Larsen, Rune; Labrie, Audrey; Heaton, Andrew; Chipperfield, Kate

    2016-08-01

    In circulation, shedding of microparticles from a variety of viable cells can be triggered by pathological activation of inflammatory processes, by activation of coagulation or complement systems, or by physical stress. Elevated microparticle content (MPC) in donor blood might therefore indicate a clinical condition of the donor which, upon transfusion, might affect the recipient. In blood products, elevated MPC might also represent product stress. Surprisingly, the MPC in blood collected from normal blood donors is highly variable, which raises the question whether donor microparticles are present in-vivo and transfer into the final blood component, and how production methods and post-production processing might affect the MPC. We measured MPC using ThromboLUX in (a) platelet-rich plasma (PRP) of 54 apheresis donors and the corresponding apheresis products, (b) 651 apheresis and 646 pooled platelet concentrates (PCs) with plasma and 414 apheresis PCs in platelet additive solution (PAS), and (c) apheresis PCs before and after transportation, gamma irradiation, and pathogen inactivation (N = 8, 7, and 12 respectively). ThromboLUX-measured MPC in donor PRP and their corresponding apheresis PC samples were highly correlated (r = 0.82, P = .001). The average MPC in pooled PC was slightly lower than that in apheresis PC and substantially lower in apheresis PC stored with PAS rather than plasma. Mirasol Pathogen Reduction treatment significantly increased MPC with age. Thus, MPC measured in donor samples might be a useful predictor of product stability, especially if post-production processes are necessary. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Computing the stresses and deformations of the human eye components due to a high explosive detonation using fluid-structure interaction model.

    Science.gov (United States)

    Karimi, Alireza; Razaghi, Reza; Navidbakhsh, Mahdi; Sera, Toshihiro; Kudo, Susumu

    2016-05-01

    In spite the fact that a very small human body surface area is comprised by the eye, its wounds due to detonation have recently been dramatically amplified. Although many efforts have been devoted to measure injury of the globe, there is still a lack of knowledge on the injury mechanism due to Primary Blast Wave (PBW). The goal of this study was to determine the stresses and deformations of the human eye components, including the cornea, aqueous, iris, ciliary body, lens, vitreous, retina, sclera, optic nerve, and muscles, attributed to PBW induced by trinitrotoluene (TNT) explosion via a Lagrangian-Eulerian computational coupling model. Magnetic Resonance Imaging (MRI) was employed to establish a Finite Element (FE) model of the human eye according to a normal human eye. The solid components of the eye were modelled as Lagrangian mesh, while an explosive TNT, air domain, and aqueous were modelled using Arbitrary Lagrangian-Eulerian (ALE) mesh. Nonlinear dynamic FE simulations were accomplished using the explicit FE code, namely LS-DYNA. In order to simulate the blast wave generation, propagation, and interaction with the eye, the ALE formulation with Jones-Wilkins-Lee (JWL) equation defining the explosive material were employed. The results revealed a peak stress of 135.70kPa brought about by detonation upsurge on the cornea at the distance of 25cm. The highest von Mises stresses were observed on the sclera (267.3kPa), whereas the lowest one was seen on the vitreous body (0.002kPa). The results also showed a relatively high resultant displacement for the macula as well as a high variation for the radius of curvature for the cornea and lens, which can result in both macular holes, optic nerve damage and, consequently, vision loss. These results may have implications not only for understanding the value of stresses and strains in the human eye components but also giving an outlook about the process of PBW triggers damage to the eye. Copyright © 2016 Elsevier Ltd

  16. Markers of Oxidative Stress in Dogs with Myxomatous Mitral Valve Disease are Influenced by Sex, Neuter Status, and Serum Cholesterol Concentration

    DEFF Research Database (Denmark)

    Reimann, M J; Häggström, J; Møller, J E

    2017-01-01

    -tocopherol [P = .003]) was associated with body condition score (BCS), but the association disappeared when cholesterol was included in the analyses. All markers of oxidative stress (MDA, oxLDL, and vitamin E) were positively associated with serum cholesterol concentration (P ≤ .04), but none were associated...... with clinical stage of MMVD. CONCLUSIONS: In conclusion, markers of oxidative stress are associated with sex, BCS, neuter status, and cholesterol. The results cannot confirm a relationship between oxidative stress and clinical stage of the disease in dogs with MMVD....

  17. Simulation of Concentrations and Dispersion of Hydrogen Sulfide (H2S Due to Incinerators of Sulfur Recovery Units in a Gas Refinery in Asaluyeh

    Directory of Open Access Journals (Sweden)

    Azam Minabi

    2017-09-01

    Conclusion: The results of this study showed that the variations of measured concentrations were consistent with those of simulated ones. Meanwhile, the contribution of neighbor industries was determined. Comparision of 8-h H2S concentrations with OSHA and NIOSH standard limits indicated that there was no significant health risk in this refinery.

  18. Changes in stream nitrate concentrations due to land management practices, ecological succession, and climate: Developing a system approach to integrated catchment response

    Science.gov (United States)

    F. Worrall; Wayne T. Swank; T. P. Burt

    2003-01-01

    This study uses time series analysis to examine long-term stream water nitrate concentration records from a pair of forested catchments at the Coweeta Hydrologic Laboratory, North Carolina, USA. Monthly average concentrations were available from 1970 through 1997 for two forested catchments, one of which was clear-felled in 1977 and the other maintained as a control....

  19. Influence of wall couple stress in MHD flow of a micropolar fluid in a porous medium with energy and concentration transfer

    Science.gov (United States)

    Khalid, Asma; Khan, Ilyas; Khan, Arshad; Shafie, Sharidan

    2018-06-01

    The intention here is to investigate the effects of wall couple stress with energy and concentration transfer in magnetohydrodynamic (MHD) flow of a micropolar fluid embedded in a porous medium. The mathematical model contains the set of linear conservation forms of partial differential equations. Laplace transforms and convolution technique are used for computation of exact solutions of velocity, microrotations, temperature and concentration equations. Numerical values of skin friction, couple wall stress, Nusselt and Sherwood numbers are also computed. Characteristics for the significant variables on the physical quantities are graphically discussed. Comparison with previously published work in limiting sense shows an excellent agreement.

  20. Dietary supplementation with a superoxide dismutase-melon concentrate reduces stress, physical and mental fatigue in healthy people: a randomised, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Carillon, Julie; Notin, Claire; Schmitt, Karine; Simoneau, Guy; Lacan, Dominique

    2014-06-19

    We aimed to investigate effects of superoxide dismutase (SOD)-melon concentrate supplementation on psychological stress, physical and mental fatigue in healthy people. A randomized, double-blind, placebo-controlled trial was performed on 61 people divided in two groups: active supplement (n = 32) and placebo (n = 29) for 12 weeks. Volunteers were given one small hard capsule per day. One capsule contained 10 mg of SOD-melon concentrate (140 U of SOD) and starch for the active supplement and starch only for the placebo. Stress and fatigue were evaluated using four psychometric scales: PSS-14; SF-36; Stroop tests and Prevost scale. The supplementation with SOD-melon concentrate significantly decreased perceived stress, compared to placebo. Moreover, quality of life was improved and physical and mental fatigue were reduced with SOD-melon concentrate supplementation. SOD-melon concentrate supplementation appears to be an effective and natural way to reduce stress and fatigue. trial approved by the ethical committee of Poitiers (France), and the ClinicalTrials.gov Identifier is NCT01767922.

  1. Dietary Supplementation with a Superoxide Dismutase-Melon Concentrate Reduces Stress, Physical and Mental Fatigue in Healthy People: A Randomised, Double-Blind, Placebo-Controlled Trial

    Directory of Open Access Journals (Sweden)

    Julie Carillon

    2014-06-01

    Full Text Available Background: We aimed to investigate effects of superoxide dismutase (SOD-melon concentrate supplementation on psychological stress, physical and mental fatigue in healthy people. Methods: A randomized, double-blind, placebo-controlled trial was performed on 61 people divided in two groups: active supplement (n = 32 and placebo (n = 29 for 12 weeks. Volunteers were given one small hard capsule per day. One capsule contained 10 mg of SOD-melon concentrate (140 U of SOD and starch for the active supplement and starch only for the placebo. Stress and fatigue were evaluated using four psychometric scales: PSS-14; SF-36; Stroop tests and Prevost scale. Results: The supplementation with SOD-melon concentrate significantly decreased perceived stress, compared to placebo. Moreover, quality of life was improved and physical and mental fatigue were reduced with SOD-melon concentrate supplementation. Conclusion: SOD-melon concentrate supplementation appears to be an effective and natural way to reduce stress and fatigue. Trial registration: trial approved by the ethical committee of Poitiers (France, and the ClinicalTrials.gov Identifier is NCT01767922.

  2. Evaluation on ultrasonic examination methods applied to Ni-base alloy weld including cracks due to stress corrosion cracking found in BWR reactor internal

    International Nuclear Information System (INIS)

    Aoki, Takayuki; Kobayashi, Hiroyuki; Higuchi, Shinichi; Shimizu, Sadato

    2005-01-01

    A Ni-base alloy weld, including cracks due to stress corrosion cracking found in the reactor internal of the oldest BWR in Japan, Tsuruga unit 1, in 1999, was examined by three (3) types of UT method. After this examination, a depth of each crack was confirmed by carrying out a little excavation with a grinder and PT examination by turns until each crack disappeared. Then, the depth measured by the former method was compared with the one measured by the latter method. In this fashion, performances of the UT methods were verified. As a result, a combination of the three types of UT method was found to meet the acceptance criteria given by ASME Sec.XI Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems-Supplement 6. In this paper, the results of the UT examination described above and their evaluation are discussed. (author)

  3. Effects of combined sewer overflow and stormwater on indicator bacteria concentrations in the Tama River due to the high population density of Tokyo Metropolitan area.

    Science.gov (United States)

    Ham, Young-Sik; Kobori, Hiromi; Takasago, Masahisa

    2009-05-01

    The indicator bacteria (standard plate count, total coliform, and fecal coliform bacteria) concentrations have been investigated using six ambient habitats (population density, percent sewer penetration, stream flow rate (m(3)/sec), percent residential area, percent forest area and percent agricultural area) in the Tama River basin in Tokyo, Japan during June 2003 to January 2005. The downstream and tributary Tama River showed higher concentrations of TC and FC bacteria than the upstream waters, which exceeded an environmental quality standard for rivers and a bathing water quality criterion. It was estimated that combined sewer overflow (CSO) and stormwater effluents contributed -4-23% to the indicator bacteria concentrations of the Tama River. The results of multiple regression analyses show that the indicator bacteria concentrations of Tama River basin are significantly affected by population density. It is concluded that the Tama River received a significant bacterial contamination load originating from the anthropogenic source.

  4. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro

    International Nuclear Information System (INIS)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi; Moorthy, Bhagavatula; Lingappan, Krithika

    2014-01-01

    Highlights: • Caffeine at 0.05 mM decreases oxidative stress in hyperoxia. • Caffeine at 1 mM decreases cell viability, increases oxidative stress in hyperoxia. • Caffeine at 1 but not 0.05 mM, abrogates hyperoxia-induced G2/M arrest. - Abstract: Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of different concentrations (0, 0.05, 0.1 and 1 mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1 mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1 mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions

  5. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi; Moorthy, Bhagavatula; Lingappan, Krithika, E-mail: lingappa@bcm.edu

    2014-08-08

    Highlights: • Caffeine at 0.05 mM decreases oxidative stress in hyperoxia. • Caffeine at 1 mM decreases cell viability, increases oxidative stress in hyperoxia. • Caffeine at 1 but not 0.05 mM, abrogates hyperoxia-induced G2/M arrest. - Abstract: Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of different concentrations (0, 0.05, 0.1 and 1 mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1 mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1 mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions.

  6. High concentration of branched-chain amino acids promotes oxidative stress, inflammation and migration of human peripheral blood mononuclear cells via mTORC1 activation.

    Science.gov (United States)

    Zhenyukh, Olha; Civantos, Esther; Ruiz-Ortega, Marta; Sánchez, Maria Soledad; Vázquez, Clotilde; Peiró, Concepción; Egido, Jesús; Mas, Sebastián

    2017-03-01

    Leucine, isoleucine and valine are essential aminoacids termed branched-chain amino acids (BCAA) due to its aliphatic side-chain. In several pathological and physiological conditions increased BCAA plasma concentrations have been described. Elevated BCAA levels predict insulin resistance development. Moreover, BCAA levels higher than 2mmol/L are neurotoxic by inducing microglial activation in maple syrup urine disease. However, there are no studies about the direct effects of BCAA in circulating cells. We have explored whether BCAA could promote oxidative stress and pro-inflammatory status in peripheral blood mononuclear cells (PBMCs) obtained from healthy donors. In cultured PBMCs, 10mmol/L BCAA increased the production of reactive oxygen species (ROS) via both NADPH oxidase and the mitochondria, and activated Akt-mTOR signalling. By using several inhibitors and activators of these molecular pathways we have described that mTOR activation by BCAA is linked to ROS production and mitochondrial dysfunction. BCAA stimulated the activation of the redox-sensitive transcription factor NF-κB, which resulted in the release of pro-inflammatory molecules, such as interleukin-6, tumor necrosis factor-α, intracellular adhesion molecule-1 or CD40L, and the migration of PBMCs. In conclusion, elevated BCAA blood levels can promote the activation of circulating PBMCs, by a mechanism that involving ROS production and NF-κB pathway activation. These data suggest that high concentrations of BCAA could exert deleterious effects on circulating blood cells and therefore contribute to the pro-inflammatory and oxidative status observed in several pathophysiological conditions. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  8. Stress !!!

    OpenAIRE

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten. Opvallend is dat mannelijke studenten uit Twente zich veel minder druk lijken te maken over hun studie. Onder vrouwen ligt de stress juist erg hoog ten opzichte van het landelijk gemiddelde.

  9. Using single-step genomic best linear unbiased predictor to enhance the mitigation of seasonal losses due to heat stress in pigs.

    Science.gov (United States)

    Fragomeni, B O; Lourenco, D A L; Tsuruta, S; Bradford, H L; Gray, K A; Huang, Y; Misztal, I

    2016-12-01

    The purposes of this study were to analyze the impact of seasonal losses due to heat stress in pigs from different breeds raised in different environments and to evaluate the accuracy improvement from adding genomic information to genetic evaluations. Data were available for 2 different swine populations: purebred Duroc animals raised in Texas and North Carolina and commercial crosses of Duroc and F females (Landrace × Large White) raised in Missouri and North Carolina; pedigrees provided links for animals from different states. Pedigree information was available for 553,442 animals, of which 8,232 pure breeds were genotyped. Traits were BW at 170 d for purebred animals and HCW for crossbred animals. Analyses were done with an animal model as either single- or 2-trait models using phenotypes measured in different states as separate traits. Additionally, reaction norm models were fitted for 1 or 2 traits using heat load index as a covariable. Heat load was calculated as temperature-humidity index greater than 70 and was averaged over 30 d prior to data collection. Variance components were estimated with average information REML, and EBV and genomic EBV (GEBV) with BLUP or single-step genomic BLUP (ssGBLUP). Validation was assessed for 146 genotyped sires with progeny in the last generation. Accuracy was calculated as a correlation between EBV and GEBV using reduced data (all animals, except the last generation) and using complete data. Heritability estimates for purebred animals were similar across states (varying from 0.23 to 0.26), and reaction norm models did not show evidence of a heat stress effect. Genetic correlations between states for heat loads were always strong (>0.91). For crossbred animals, no differences in heritability were found in single- or 2-trait analysis (from 0.17 to 0.18), and genetic correlations between states were moderate (0.43). In the reaction norm for crossbreeds, heritabilities ranged from 0.15 to 0.30 and genetic correlations

  10. Juvenile life stages of the brown alga Fucus serratus L. are more sensitive to combined stress from high copper concentration and temperature than adults

    DEFF Research Database (Denmark)

    Nielsen, Søren Laurentius; Nielsen, Hanne Dalsgaard; Pedersen, Morten Foldager

    2014-01-01

    of high copper concentration was amplified by high temperature. We conclude that juveniles of F. serratus are more susceptible to environmental stressors than adult specimens and recommend therefore including early life stages when assessing the risk of exposure to toxic compounds. Considering...... the response of adult specimens only may lead to false conclusions regarding the ecological impact of environmental stress...

  11. Influence of wall couple stress in MHD flow of a micropolar fluid in a porous medium with energy and concentration transfer

    Directory of Open Access Journals (Sweden)

    Asma Khalid

    2018-06-01

    Full Text Available The intention here is to investigate the effects of wall couple stress with energy and concentration transfer in magnetohydrodynamic (MHD flow of a micropolar fluid embedded in a porous medium. The mathematical model contains the set of linear conservation forms of partial differential equations. Laplace transforms and convolution technique are used for computation of exact solutions of velocity, microrotations, temperature and concentration equations. Numerical values of skin friction, couple wall stress, Nusselt and Sherwood numbers are also computed. Characteristics for the significant variables on the physical quantities are graphically discussed. Comparison with previously published work in limiting sense shows an excellent agreement. Keywords: Micropolor fluid, Microrotation, MHD, Porosity, Wall couple stress, Exact solutions

  12. Effect of prenatal restraint stress and morphine co-administration on plasma vasopressin concentration and anxiety behaviors in adult rat offspring.

    Science.gov (United States)

    Nakhjiri, Elnaz; Saboory, Ehsan; Roshan-Milani, Shiva; Rasmi, Yousef; Khalafkhani, Davod

    2017-03-01

    Stressful events and exposure to opiates during gestation have important effects on the later mental health of the offspring. Anxiety is among the most common mental disorders. The present study aimed to identify effects of prenatal restraint stress and morphine co-administration on plasma vasopressin concentration (PVC) and anxiety behaviors in rats. Pregnant rats were divided into four groups (n = 6, each): saline, morphine, stress + saline and stress + morphine treatment. The stress procedure consisted of restraint twice per day, two hours per session, for three consecutive days starting on day 15 of pregnancy. Rats in the saline and morphine groups received either 0.9% saline or morphine intraperitoneally on the same days. In the morphine/saline + stress groups, rats were exposed to restraint stress and received either morphine or saline intraperitoneally. All offspring were tested in an elevated plus maze (EPM) on postnatal day 90 (n = 6, each sex), and anxiety behaviors of each rat were recorded. Finally, blood samples were collected to determine PVC. Prenatal morphine exposure reduced anxiety-like behaviors. Co-administration of prenatal stress and morphine increased locomotor activity (LA) and PVC. PVC was significantly lower in female offspring of the morphine and morphine + stress groups compared with males in the same group, but the opposite was seen in the saline + stress group. These data emphasize the impact of prenatal stress and morphine on fetal neuroendocrine development, with long-term changes in anxiety-like behaviors and vasopressin secretion. These changes are sex specific, indicating differential impact of prenatal stress and morphine on fetal neuroendocrine system development. Lay Summary Pregnant women are sometimes exposed to stressful and painful conditions which may lead to poor outcomes for offspring. Opiates may provide pain and stress relief to these mothers. In this study, we used an experimental model of

  13. Cerebrovascular/cardiovascular diseases and mental disorders due to overwork and work-related stress among local public employees in Japan.

    Science.gov (United States)

    Yamauchi, Takashi; Yoshikawa, Toru; Sasaki, Takeshi; Matsumoto, Shun; Takahashi, Masaya; Suka, Machi; Yanagisawa, Hiroyuki

    2018-02-07

    In Japan, overwork-related disorders occur among local public employees as well as those in private businesses. However, to date, there are no studies reporting the state of compensation for cerebrovascular/cardiovascular diseases (CCVD) and mental disorders due to overwork or work-related stress among local public employees in Japan over multiple years. This report examined the recent trend of overwork-related CCVD and mental disorders, including the incidence rates of these disorders, among local public employees in Japan from the perspective of compensation for public accidents, using data from the Japanese Government and relevant organizations. Since 2000, compared to CCVD, there has been an overall increase in the number of claims and cases of compensation for mental disorders. Over half of the individuals receiving compensation for mental disorders were either in their 30s or younger. About 47% of cases of mental disorders were compensated due to work-related factors other than long working hours. The incidence rate by job type was highest among "police officials" and "fire department officials" for compensated CCVD and mental disorders cases, respectively. Changes in the trend of overwork-related disorders among local public employees in Japan under a legal foundation should be closely monitored.

  14. Effect of temperature and ionic impurities at very low concentrations on stress corrosion cracking of type 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ruther, W.E.; Soppet, W.K.; Kassner, T.F.

    1984-11-01

    The relative effect of approx. 12 anion species, in conjunction with hydrogen and sodium cations, on the stress-corrosion-cracking (SCC) behavior of lightly sensitized Type 304 stainless steel was investigated in constant-extension-rate-tensile (CERT) tests at 289/sup 0/C in water with 0.2 ppM dissolved oxygen at total conductivity values of less than or equal to 1 ..mu..S/cm. The results show that the sulfur species, either in acid or sodium form, produce the highest degree of IGSCC relative to other anions. The effect of temperature on the SCC behavior of the material was investigated in CERT tests over the range 110 to 320/sup 0/C in high-purity water and in water containing 0.1 and 1.0 ppM sulfate as H/sub 2/SO/sub 4/ at a dissolved oxygen concentration of 0.2 ppM. The CERT parameters were correlated with impurity concentration (i.e., conductivity) and the electrochemical potential of platinum and Type 304 stainless steel electrodes in the high-temperature environments. Maximum IGSCC occurred at temperatures between approx. 200 and 250/sup 0/C in high-purity water, and the addition of sulfate increased the average crack growth rates and the temperature range over which maximum susceptibility occurred. A distinct transition from intergranular to transgranular and ultimately to a ductile failure mode was observed as the temperature increased from approx. 270 to 320/sup 0/C in high-purity water. This transition was attributed to a decrease in the open-circuit corrosion potential of the steel below a critical value of approx. 0 mV(SHE) at the higher temperature. A large decrease in the crack growth rates of fracture-mechanics-type specimens of the steel was also found when the temperature was increased from 289 to 320/sup 0/C in high-purity water with 0.2 ppM dissolved oxygen. 26 references, 8 figures, 6 tables.

  15. Effect of temperature and ionic impurities at very low concentrations on stress corrosion cracking of type 304 stainless steel

    International Nuclear Information System (INIS)

    Ruther, W.E.; Soppet, W.K.; Kassner, T.F.

    1984-11-01

    The relative effect of approx. 12 anion species, in conjunction with hydrogen and sodium cations, on the stress-corrosion-cracking (SCC) behavior of lightly sensitized Type 304 stainless steel was investigated in constant-extension-rate-tensile (CERT) tests at 289 0 C in water with 0.2 ppM dissolved oxygen at total conductivity values of less than or equal to 1 μS/cm. The results show that the sulfur species, either in acid or sodium form, produce the highest degree of IGSCC relative to other anions. The effect of temperature on the SCC behavior of the material was investigated in CERT tests over the range 110 to 320 0 C in high-purity water and in water containing 0.1 and 1.0 ppM sulfate as H 2 SO 4 at a dissolved oxygen concentration of 0.2 ppM. The CERT parameters were correlated with impurity concentration (i.e., conductivity) and the electrochemical potential of platinum and Type 304 stainless steel electrodes in the high-temperature environments. Maximum IGSCC occurred at temperatures between approx. 200 and 250 0 C in high-purity water, and the addition of sulfate increased the average crack growth rates and the temperature range over which maximum susceptibility occurred. A distinct transition from intergranular to transgranular and ultimately to a ductile failure mode was observed as the temperature increased from approx. 270 to 320 0 C in high-purity water. This transition was attributed to a decrease in the open-circuit corrosion potential of the steel below a critical value of approx. 0 mV(SHE) at the higher temperature. A large decrease in the crack growth rates of fracture-mechanics-type specimens of the steel was also found when the temperature was increased from 289 to 320 0 C in high-purity water with 0.2 ppM dissolved oxygen. 26 references, 8 figures, 6 tables

  16. Markers of Oxidative Stress in Dogs with Myxomatous Mitral Valve Disease are Influenced by Sex, Neuter Status, and Serum Cholesterol Concentration

    DEFF Research Database (Denmark)

    Reimann, M. J.; Haggstrom, J.; Moller, J. E.

    2017-01-01

    Background Cardiovascular disease has been associated with oxidative stress, which has been suggested to contribute to myocardial remodeling in human patients. Little is known about the relationship between myxomatous mitral valve disease (MMVD) and oxidative stress in dogs. Objective To determin...... with clinical stage of MMVD. Conclusions In conclusion, markers of oxidative stress are associated with sex, BCS, neuter status, and cholesterol. The results cannot confirm a relationship between oxidative stress and clinical stage of the disease in dogs with MMVD.......Background Cardiovascular disease has been associated with oxidative stress, which has been suggested to contribute to myocardial remodeling in human patients. Little is known about the relationship between myxomatous mitral valve disease (MMVD) and oxidative stress in dogs. Objective To determine...... whether clinical stage of MMVD is associated with changes in the plasma concentrations of certain markers of oxidative stress in clinically healthy dogs and dogs with MMVD. Animals Seventy five privately owned dogs: 59 cavalier King Charles Spaniels (CKCS) with different severities of MMVD and 16 dogs...

  17. Plasma concentrations of inflammatory cytokines rise rapidly during ECMO-related SIRS due to the release of preformed stores in the intestine.

    Science.gov (United States)

    McILwain, R Britt; Timpa, Joseph G; Kurundkar, Ashish R; Holt, David W; Kelly, David R; Hartman, Yolanda E; Neel, Mary Lauren; Karnatak, Rajendra K; Schelonka, Robert L; Anantharamaiah, G M; Killingsworth, Cheryl R; Maheshwari, Akhil

    2010-01-01

    Extracorporeal membrane oxygenation (ECMO) is a life-saving support system used in neonates and young children with severe cardiorespiratory failure. Although ECMO has reduced mortality in these critically ill patients, almost all patients treated with ECMO develop a systemic inflammatory response syndrome (SIRS) characterized by a 'cytokine storm', leukocyte activation, and multisystem organ dysfunction. We used a neonatal porcine model of ECMO to investigate whether rising plasma concentrations of inflammatory cytokines during ECMO reflect de novo synthesis of these mediators in inflamed tissues, and therefore, can be used to assess the severity of ECMO-related SIRS. Previously healthy piglets (3-week-old) were subjected to venoarterial ECMO for up to 8 h. SIRS was assessed by histopathological analysis, measurement of neutrophil activation (flow cytometry), plasma cytokine concentrations (enzyme immunoassays), and tissue expression of inflammatory genes (PCR/western blots). Mast cell degranulation was investigated by measurement of plasma tryptase activity. Porcine neonatal ECMO was associated with systemic inflammatory changes similar to those seen in human neonates. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) concentrations rose rapidly during the first 2 h of ECMO, faster than the tissue expression of these cytokines. ECMO was associated with increased plasma mast cell tryptase activity, indicating that increased plasma concentrations of inflammatory cytokines during ECMO may result from mast cell degranulation and associated release of preformed cytokines stored in mast cells. TNF-alpha and IL-8 concentrations rose faster in plasma than in the peripheral tissues during ECMO, indicating that rising plasma levels of these cytokines immediately after the initiation of ECMO may not reflect increasing tissue synthesis of these cytokines. Mobilization of preformed cellular stores of inflammatory cytokines such as in mucosal mast cells may have

  18. Stress !!!

    NARCIS (Netherlands)

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten.

  19. The Effect of Exogenous Spermidine Concentration on Polyamine Metabolism and Salt Tolerance in Zoysiagrass (Zoysia japonica Steud) Subjected to Short-Term Salinity Stress.

    Science.gov (United States)

    Li, Shucheng; Jin, Han; Zhang, Qiang

    2016-01-01

    Salt stress, particularly short-term salt stress, is among the most serious abiotic factors limiting plant survival and growth in China. It has been established that exogenous spermidine (Spd) stimulates plant tolerance to salt stress. The present study utilized two zoysiagrass cultivars commonly grown in China that exhibit either sensitive (cv. Z081) or tolerant (cv. Z057) adaptation capacity to salt stress. The two cultivars were subjected to 200 mM salt stress and treated with different exogenous Spd concentrations for 8 days. Polyamine [diamine putrescine (Put), tetraamine spermine (Spm), and Spd], H2O2 and malondialdehyde (MDA) contents and polyamine metabolic (ADC, ODC, SAMDC, PAO, and DAO) and antioxidant (superoxide dismutase, catalase, and peroxidase) enzyme activities were measured. The results showed that salt stress induced increases in Spd and Spm contents and ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC), and diamine oxidase (DAO) activities in both cultivars. Exogenous Spd application did not alter polyamine contents via regulation of polyamine-degrading enzymes, and an increase in polyamine biosynthetic enzyme levels was observed during the experiment. Increasing the concentration of exogenous Spd resulted in a tendency of the Spd and Spm contents and ODC, SAMDC, DAO, and antioxidant enzyme activities to first increase and then decrease in both cultivars. H2O2 and MDA levels significantly decreased in both cultivars treated with Spd. Additionally, in both cultivars, positive correlations between polyamine biosynthetic enzymes (ADC, SAMDC), DAO, and antioxidant enzymes (SOD, POD, CAT), but negative correlations with H2O2 and MDA levels, and the Spd + Spm content were observed with an increase in the concentration of exogenous Spd.

  20. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects after prolonged culture in a low non-stimulating glucose concentration.

    Science.gov (United States)

    Roma, L P; Pascal, S M; Duprez, J; Jonas, J-C

    2012-08-01

    Pancreatic beta cells chronically exposed to low glucose concentrations show signs of oxidative stress, loss of glucose-stimulated insulin secretion (GSIS) and increased apoptosis. Our aim was to confirm the role of mitochondrial oxidative stress in rat islet cell apoptosis under these culture conditions and to evaluate whether its reduction similarly improves survival and GSIS. Apoptosis, oxidative stress-response gene mRNA expression and glucose-induced stimulation of mitochondrial metabolism, intracellular Ca(2+) concentration and insulin secretion were measured in male Wistar rat islets cultured for 1 week in RPMI medium containing 5-10 mmol/l glucose with or without manganese(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) or N-acetyl-L-: cysteine (NAC). Oxidative stress was measured in islet cell clusters cultured under similar conditions using cytosolic and mitochondrial redox-sensitive green fluorescent protein (roGFP1/mt-roGFP1). Prolonged culture in 5 vs 10 mmol/l glucose increased mt-roGFP1 (but not roGFP1) oxidation followed by beta cell apoptosis and loss of GSIS resulting from reduced insulin content, mitochondrial metabolism, Ca(2+) influx and Ca(2+)-induced secretion. Tolbutamide-induced, but not high K(+)-induced, Ca(2+) influx was also suppressed. Under these conditions, MnTBAP, but not NAC, triggered parallel ~50-70% reductions in mt-roGFP1 oxidation and beta cell apoptosis, but failed to protect against the loss of GSIS despite significant improvement in glucose-induced and tolbutamide-induced Ca(2+) influx. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects during culture in a low glucose concentration. Thus, targeting beta cell survival may not be sufficient to restore insulin secretion when beta cells suffer from prolonged mitochondrial oxidative stress, e.g. in the context of reduced glucose metabolism.

  1. The effects of stress concentrations on reaction progress: an example from experimental growth of magnesio-aluminate spinel at corundum - periclase interfaces under uniaxial load

    Science.gov (United States)

    Jerabek, Petr; Abart, Rainer; Rybacki, Erik; Habler, Gerlinde

    2014-05-01

    The study aims to understand the reaction progress and chemical, microstructural and textural evolution of magnesio-aluminate spinel reaction rims formed at varying experimental settings (load, temperature and experiment duration). The spinel rims were grown at the contacts between periclase and corundum at temperatures of 1250°C to 1350°C and dry atmosphere, maintained by a constant argon gas flow, under uniaxial load of 0.026 and 0.26 kN per 9 mm2 of initial contact area. Single crystals of periclase with [100] and of corundum with [0001] perpendicular to the polished reaction interface as well as polycrystalline corundum were used as starting materials. Two loading procedures, immediate application of the load before heating and loading after the desired temperature had been reached, were used. An important byproduct of our experiments stemmed from the immediate application of the load, which led to deformation twinning and fracturing of corundum. This internal deformation of corundum disturbed the reaction interface and introduced loci of concentrated stress due to opening of void spaces in between the reactant crystals. Whenever cracks formed in the initial stages of an experiment, the void space opened immediately and no spinel formed along these interface segments. In the case of deformation twinning, the decreased rim thickness indicates later opening of void spaces. This is because next to twins, the reaction interface is characterized by tight physical contact on the one side and less tight contact on the other side of the twin individual. The tight contacts are characterized by enhanced reaction progress which together with the overall positive volume change of the reaction and limits on plasticity of the studied phases led to the opening of void spaces at places characterized by less tight contacts. The thickness variations are less pronounced in our high load (0.26 kN) experiments where periclase behaves plastically and to some extent reduces the

  2. Transgenic mice overexpressing glia maturation factor-β, an oxidative stress inducible gene, show premature aging due to Zmpste24 down-regulation.

    Science.gov (United States)

    Imai, Rika; Asai, Kanae; Hanai, Jun-ichi; Takenaka, Masaru

    2015-07-01

    Glia Maturation Factor-β (GMF), a brain specific protein, is induced by proteinuria in renal tubules. Ectopic GMF overexpression causes apoptosisin vitro via cellular vulnerability to oxidative stress. In order to examine the roles of GMF in non-brain tissue, we constructed transgenic mice overexpressing GMF (GMF-TG). The GMF-TG mice exhibited appearance phenotypes associated with premature aging. The GMF-TG mice also demonstrated short lifespans and reduced hair regrowth, suggesting an accelerated aging process. The production of an abnormal lamin A, a nuclear envelope protein, plays a causal role in both normal aging and accelerated aging diseases, known as laminopathies. Importantly, we identified the abnormal lamin A (prelamin A), accompanied by a down-regulation of a lamin A processing enzyme (Zmpste24) in the kidney of the GMF-TG mice. The GMF-TG mice showed accelerated aging in the kidney, compared with wild-type mice, showing increased TGF-β1, CTGF gene and serum creatinine. The gene expression of p21/waf1 was increased at an earlier stage of life, at 10 weeks, which was in turn down-regulated at a later stage, at 60 weeks. In conclusion, we propose that GMF-TG mice might be a novel mouse model of accelerated aging, due to the abnormal lamin A.

  3. Days out of role due to common physical and mental conditions: results from the Northern Ireland study of health and stress.

    Science.gov (United States)

    Ennis, Edel; O'Neill, S; Murphy, S; Bunting, B

    2016-11-01

    Days out of role due to health problems are a major source of lost human capital. We examined the relative importance of common physical and mental disorders in accounting for days out of role in Northern Ireland using the Northern Ireland Study of Health and Stress (NISHS) WHO World Mental Health (WMH) Survey. Face-to-face interviews were carried out with 4340 respondents (68.4 % response rate). Multiple regression analysis estimated associations of specific chronic physical disorders and mental disorders conditions and comorbidities with days out of role controlling for basic socio-demographics. Overall, 16.8 % of respondents had at least one day totally out of role in the previous year. The strongest population-level effect was associated with arthritis, which accounted for 23.5 % of all days out of role. The strongest individual-level effects (days out of role per year) were associated with any anxiety disorder (32.3) arthritis (26.1) and pain (22.0). The 11 conditions accounted for 93 % of all days out of role, as measured by population attributable risk proportions (PARPs). Common health conditions, including mental disorders, make up a large proportion of the number of days out of role and should be addressed to substantially increase overall productivity.

  4. Bovine Mammary Nutrigenomics and Changes in the Milk Composition due to Rapeseed or Sunflower Oil Supplementation of High-Forage or High-Concentrate Diets.

    Science.gov (United States)

    Leroux, Christine; Bernard, Laurence; Faulconnier, Yannick; Rouel, Jacques; de la Foye, Anne; Domagalski, Jordann; Chilliard, Yves

    2016-01-01

    Fatty acid (FA) composition plays a crucial role in milk nutritional quality. Despite the known nutritional regulation of ruminant milk composition, the overall mammary mechanisms underlying this regulation are far from being understood. The aim of our study was to determine nutritional regulation of mammary transcriptomes in relation to the cow milk composition. Twelve cows received diets differing in the forage-to-concentrate ratio [high forage (HF) and low forage (LF)] supplemented or not with lipids [HF with whole intact rapeseeds (RS) and LF sunflower oil (SO)] in a 4 × 4 Latin square design. Milk production and FA composition were determined. The gene expression profile was studied using RT-qPCR and a bovine microarray. Our results showed a higher amplitude of milk composition and mammary transcriptome responses to lipid supplementation with the LF-SO compared with the LF diet than with the HF-RS compared with the HF diet. Forty-nine differentially expressed genes, including genes involved in lipid metabolism, were identified with LF-SO versus LF, whereas RS supplementation to the HF diet did not affect the mammary transcriptome. This study highlights different responses to lipid supplementation of milk production and composition and mammary transcriptomes depending on the nature of lipid supplementation and the percentage of dietary concentrate. © 2016 S. Karger AG, Basel.

  5. Dynamic Stress Concentration at the Boundary of an Incision at the Plate Under the Action of Weak Shock Waves

    Directory of Open Access Journals (Sweden)

    Mikulich Olena

    2017-09-01

    Full Text Available This paper proposes the novel technique for analysis of dynamic stress state of multi-connected infinite plates under the action of weak shock waves. For solution of the problem it uses the integral and discrete Fourier transforms. Calculation of transformed dynamic stresses at the incisions of plates is held using the boundary-integral equation method and the theory of complex variable functions. The numerical implementation of the developed algorithm is based on the method of mechanical quadratures and collocation technique. For calculation of originals of the dynamic stresses it uses modified discrete Fourier transform. The algorithm is effective in the analysis of the dynamic stress state of defective plates.

  6. Associations of hair cortisol concentration with self-reported measures of stress and mental health-related factors in a pooled database of diverse community samples.

    Science.gov (United States)

    Wells, Samantha; Tremblay, Paul F; Flynn, Andrea; Russell, Evan; Kennedy, James; Rehm, Jürgen; Van Uum, Stan; Koren, Gideon; Graham, Kathryn

    2014-07-01

    A pooled database from diverse community samples was used to examine the associations of hair cortisol concentration (HCC) with self-reported stress and stress-linked mental health measures, including depression, anxiety, alcohol and drug use, disability and experiences with aggression. As part of innovative research using a mobile laboratory to study community mental health, data were pooled from five sub-studies: a random sample of the general population (n = 70), people who had received treatment for a mental health and/or substance use problem (n = 78), family members of people treated for mental health and/or substance use problems (n = 49), community volunteers who sometimes felt sad or blue or thought they drank too much (n = 83) and young adults in intimate partner relationships (n = 44). All participants completed a computerized questionnaire including standard measures of perceived stress, chronic stress, depression, anxiety, hazardous drinking, tobacco use, prescription drug use, illicit drug use, disability and intimate partner aggression. HCC was significantly associated with use of antidepressants, hazardous drinking, smoking and disability after adjusting for sub-study and potential confounders (sex, body-mass index, use of glucocorticoids and hair dyed). In addition, preliminary analyses suggest a significant curvilinear relationship between HCC and perceived stress; specifically, HCC increased with higher perceived stress but decreased at the highest level of stress. Overall, HCC was associated with mental health-related variables mainly reflecting substance use or experiencing a disability. The relationship between HCC and self-reported stress is unclear and needs further research.

  7. Use of an integrated biomarker-based strategy to evaluate physiological stress responses induced by environmental concentrations of caffeine in the Mediterranean mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Capolupo, Marco; Valbonesi, Paola; Kiwan, Alisar; Buratti, Sara; Franzellitti, Silvia; Fabbri, Elena

    2016-09-01

    The occurrence of caffeine (CF), a biologically active drug, has widely been documented in coastal waters, and whether its environmental concentrations do represent a threat for marine organisms is unclear. The present study aimed at assessing sub-lethal effects induced by a 7-day exposure to environmentally relevant concentrations of CF (5, 50 and 500ng/L) in the Mediterranean mussel, Mytilus galloprovincialis. CF in water and mussel tissues, and a battery of biomarkers, including lysosomal parameters of general stress, oxidative stress responses and endpoints of neurological and genetic damages, were evaluated and tested for significance vs controls (pemerging contaminants in marine invertebrates. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Estimation of concentration of naturally occurring 210Po in dietary items collected from Tarapur site and public dose due to ingestion

    International Nuclear Information System (INIS)

    Sudheendran, V.; Baburajan, A.; Ravi, P.M.; Sarkar, P.K.

    2013-01-01

    210 Po is one of the naturally occurring radioactive (T 1/2 : 138.4 d, Energy: 5.297 MeV) member of 238 U series which delivers a significantly high natural dose through ingestion because of its high specific activity (165 TBq/g). The main source of 210 Po in atmosphere is 222 Rn. The paper presents the results of analysis of 210 Po in different terrestrial and aquatic environmental matrices like marine seafood, vegetable, drinking water, crop etc and estimation of population dose due to their consumption at Tarapur, west coast of India. The annual Committed Effective Dose (CED) received by the member of Tarapur population through consumption of these food items estimated to be 102.4 μSV which is 6.3 % of the total internal dose from natural sources. Contribution from marine food items was found to be significant (78.7%) compared to other terrestrial food items. (author)

  9. Social isolation stress and chronic glutathione deficiency have a common effect on the glutamine-to-glutamate ratio and myo-inositol concentration in the mouse frontal cortex.

    Science.gov (United States)

    Corcoba, Alberto; Gruetter, Rolf; Do, Kim Q; Duarte, João M N

    2017-09-01

    Environmental stress can interact with genetic predisposition to increase the risk of developing psychopathology. In this work, we tested the hypothesis that social isolation stress interacts with impaired glutathione synthesis and have cumulative effects on the neurochemical profile of the frontal cortex. A mouse model with chronic glutathione deficit induced by knockout (-/-) of the glutamate-cysteine ligase modulatory subunit (Gclm) was exposed to social isolation stress from weaning to post-natal day 65. Using magnetic resonance methods at high-field (14.1 T), we analysed the neurochemical profile in the frontal cortex, brain size and ventricular volume of adult animals. Glutathione deficit was accompanied by elevated concentrations of N-acetylaspartate, alanine, and glutamine, as well as the ratio of glutamine-to-glutamate (Gln/Glu), and by a reduction in levels of myo-inositol and choline-containing compounds in the frontal cortex of -/- animals with respect to wild-type littermates. Although there was no significant interaction between social isolation stress and glutathione deficiency, mice reared in isolation displayed lower myo-inositol concentration (-8.4%, p social isolation had no effect on these parameters. We conclude that social isolation caused neurochemical alterations that may add to those associated to impaired glutathione synthesis. © 2017 International Society for Neurochemistry.

  10. Treatment of β-Thalassemia/Hemoglobin E with Antioxidant Cocktails Results in Decreased Oxidative Stress, Increased Hemoglobin Concentration, and Improvement of the Hypercoagulable State

    Directory of Open Access Journals (Sweden)

    Orn-uma Yanpanitch

    2015-01-01

    Full Text Available Studies on the antioxidant treatment for thalassemia have reported variable outcomes. However, treatment of thalassemia with a combination of hydrophobic and hydrophilic antioxidants and an iron chelator has not been studied. This study investigated the effects of antioxidant cocktails for the treatment of β-thalassemia/hemoglobin E (HbE, which is the most common form of β-thalassemia in Southeast Asia. Sixty patients were divided into two groups receiving N-acetylcysteine, deferiprone, and either curcuminoids (CUR or vitamin E (Vit-E, and their hematological parameters, iron load, oxidative stress, and blood coagulation potential were evaluated. Patients were classified as responders if they showed the improvements of the markers of iron load and oxidative stress, otherwise as nonresponders. During treatment, the responders in both groups had significantly decreased iron load, oxidative stress, and coagulation potential and significantly increased antioxidant capacity and hemoglobin concentration. The significantly maximum increase (P<0.01 in hemoglobin concentration was 11% at month 4 in CUR group responders and 10% at month 10 in Vit-E group responders. In conclusion, the two antioxidant cocktails can improve anemia, iron overload, oxidative stress, and hypercoagulable state in β-thalassemia/HbE.

  11. Oxidative stress due to (R)-styrene oxide exposure and the role of antioxidants in non-Swiss albino (NSA) mice.

    Science.gov (United States)

    Meszka-Jordan, Anna; Mahlapuu, Riina; Soomets, Ursel; Carlson, Gary P

    2009-01-01

    Styrene produces lung and liver damage that may be related to oxidative stress. The purpose of this study was to investigate the toxicity of (R)-styrene oxide (R-SO), the more active enantiomeric metabolite of styrene, and the protective properties of the antioxidants glutathione (GSH), N-acetylcysteine (NAC), and 4-methoxy-L-tyrosinyl-gamma-L-glutamyl-L-cysteinyl-glycine (UPF1) against R-SO-induced toxicity in non-Swiss Albino (NSA) mice. UPF1 is a synthetic GSH analog that was shown to have 60 times the ability to scavenge reactive oxygen species (ROS) in comparison to GSH. R-SO toxicity to the lung was measured by elevations in the activity of lactate dehydrogenase (LDH), protein concentration, and number of cells in bronchoalveolar lavage fluid (BALF). Toxicity to the liver was measured by increases in serum sorbitol dehydrogenase (SDH) activity. Antioxidants were not able to decrease the adverse effects of R-SO on lung. However, NAC (200 mg/kg) ip and GSH (600 mg/kg), administered orally prior to R-SO (300 mg/kg) ip, showed significant protection against liver toxicity as measured by SDH activity. Unexpectedly, a synthetic GSH analog, UPF1 (0.8 mg/kg), administered intravenously (iv) prior to R-SO, produced a synergistic effect with regard to liver and lung toxicity. Treatment with UPF1 (0.8 mg/kg) iv every other day for 1 wk for preconditioning prior to R-SO ip did not result in any protection against liver and lung toxicity, but rather enhanced the toxicity when administered prior R-SO. The results of the present study demonstrated protection against R-SO toxicity in liver but not lung by the administration of the antioxidants NAC and GSH.

  12. Interaction between diffusion and chemical stresses

    International Nuclear Information System (INIS)

    Yang Fuqian

    2005-01-01

    The present work studies the interaction between chemical stresses and diffusion. A new relation between hydrostatic stress and concentration of solute atoms is established. For a solid free of action of body force, the Laplacian of the hydrostatic stress is proportional to the Laplacian of the concentration of solute atoms, that is, deviation of the hydrostatic stress from its local average is proportional to deviation of the local concentration of solute atoms. A general relationship among surface concentration of solute atoms, normal stress and surface deformation of a solid is then derived, in which the normal stress is dependent on the mean curvature of the undeformed surface and tangential components of the surface displacement. A closed-form solution of the steady state concentration of solute atoms in a thin plate is obtained. It turns out that linear distribution of solute atoms in the plate is non-existent due to the interaction between chemical stresses and diffusion

  13. Three Dimensional Parametric Analyses of Stress Concentration Factor and Its Mitigation in Isotropic and Orthotropic Plate with Central Circular Hole Under Axial In-Plane Loading

    Science.gov (United States)

    Nagpal, Shubhrata; Jain, Nitin Kumar; Sanyal, Shubhashis

    2016-01-01

    The problem of finding the stress concentration factor of a loaded rectangular plate has offered considerably analytical difficulty. The present work focused on understanding of behavior of isotropic and orthotropic plate subjected to static in-plane loading using finite element method. The complete plate model configuration has been analyzed using finite element method based software ANSYS. In the present work two parameters: thickness to width of plate (T/A) and diameter of hole to width of plate (D/A) have been varied for analysis of stress concentration factor (SCF) and its mitigation. Plates of five different materials have been considered for complete analysis to find out the sensitivity of stress concentration factor. The D/A ratio varied from 0.1 to 0.7 for analysis of SCF and varied from 0.1 to 0.5 for analyzing the mitigation of SCF. 0.01, 0.05 and 0.1 are considered as T/A ratio for all the cases. The results are presented in graphical form and discussed. The mitigation in SCF reported is very encouraging. The SCF is more sensitive to D/A ratio as compared to T/A.

  14. Serum Lipid Concentrations in Croatian Veterans with Post-traumatic Stress Disorder, Post-traumatic Stress Disorder Comorbid with Major Depressive Disorder, or Major Depressive Disorder

    OpenAIRE

    Karlovi?, Dalibor; Buljan, Danijel; Martinac, Marko; Mar?inko, Darko

    2004-01-01

    The aim of this study was to assess eventual differences in serum cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, LDL-C/HDL-C ratio between veterans with combat-related posttraumatic stress disorder (PTSD) only or comorbid with major depressive disorder (MDD), veterans with combat experiences with MDD, and healthy control group. PTSD and/ or MDD were diagnose according to structured clinical interview based on DSM-IV crite...

  15. How do line managers experience and handle the return to work of employees on sick leave due to work-related stress? A one-year follow-up study.

    Science.gov (United States)

    Ladegaard, Yun; Skakon, Janne; Elrond, Andreas Friis; Netterstrøm, Bo

    2017-08-28

    To examine how line managers experience and manage the return to work process of employees on sick leave due to work-related stress and to identify supportive and inhibiting factors. Semi-structured interviews with 15 line managers who have had employees on sick leave due to work-related stress. The grounded theory approach was employed. Even though managers may accept the overall concept of work-related stress, they focus on personality and individual circumstances when an employee is sick-listed due to work-related stress. The lack of a common understanding of stress creates room for this focus. Line managers experience cross-pressure, discrepancies between strategic and human-relationship perspectives and a lack of organizational support in the return to work process. Organizations should aim to provide support for line managers. Research-based knowledge and guidelines on work-related stress and return to work process are essential, as is the involvement of coworkers. A commonly accepted definition of stress and a systematic risk assessment is also important. Cross-pressure on line managers should be minimized and room for adequate preventive actions should be provided as such an approach could support both the return to work process and the implementation of important interventions in the work environment. Implication for rehabilitation Organizations should aim to provide support for line managers handling the return to work process. Cross-pressure on line managers should be minimized and adequate preventive actions should be provided in relation to the return to work process. Research-based knowledge and guidelines on work-related stress and return to work are essential. A common and formal definition of stress should be emphasized in the workplace.

  16. Repeated short-term stress synergizes the ROS signalling through up regulation of NFkB and iNOS expression induced due to combined exposure of trichloroethylene and UVB rays.

    Science.gov (United States)

    Ali, Farrah; Sultana, Sarwat

    2012-01-01

    Restraint stress is known to catalyse the pathogenesis of the variety of chronic inflammatory disorders. The present study was designed to evaluate the effect of repeated short-term stress (RRS) on cellular transduction apart from oxidative burden and early tumour promotional biomarkers induced due to combined exposure of trichloroethylene (TCE) and Ultra-violet radiation (UVB). RRS leads to the increase in the expression of the stress responsive cellular transduction elements NFkB-p65 and activity of iNOS in the epidermal tissues of mice after toxicant exposure. RRS augments the steep depletion of the cellular antioxidant machinery which was evidenced by the marked depletion in GSH (Glutathione and GSH dependant enzymes), superoxide dismutase and catalase activity that were observed at significance level of P stressed animals and down regulation of DT-diaphorase activity (P short-term stress in the toxic response of TCE and UVB radiation.

  17. Stress.

    Science.gov (United States)

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself.

  18. Variation of radon concentration in Guwahati, Assam due to six earthquakes (Magnitude >5) occurred in N.E. India: a comparative study with baseline disparity

    International Nuclear Information System (INIS)

    Laskar, I.; Goswami, A.K.; Chetry, G.; Roy, U.C.; Mahanta, Kashyap; Chowdhury, Jyotirmoy Das; Laskar, J.

    2013-01-01

    Six earthquakes (M>5) have occurred in N.E. India within a time span of forty two days from August 11, 2009 to September 21, 2009. The minimum and maximum values of magnitudes of these earthquakes are 5.0 and 6.3 respectively in Richter Scale (RS). The origins of these earthquakes are reported to be Indo-Myanmar border, Sonitpur dist of Assam and neighboring Bhutan (USGS report). We, in our lab in Guwahati, Assam, have observed prominent radon peaks in the continuously monitored Alpha-GUARD, which can be regarded as precursor peaks for these earthquakes except the one that has origin in Bhutan. The post -effect of this earthquake was observed as a radon peak one day later. This may be due to the fact that the Bhutan tectonic plate and the tectonic plate on which Guwahati along with Shillong shield do not lie on the same plate. The extended part of the Kopili Fault has separated the Bhutan tectonic plate and makes the region more seismic. Continuous seven years GPS data analysis has given a remarkable depiction. The baseline analysis between IISC, Bangalore and some of our campaign mode GPS stations near Guwahati have made the picture clear. An analysis of available data is reported in this paper. (author)

  19. Suppression of Human T Cell Proliferation Mediated by the Cathepsin B Inhibitor, z-FA-FMK Is Due to Oxidative Stress.

    Directory of Open Access Journals (Sweden)

    Tanuja Rajah

    Full Text Available The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-fluoromethyl ketone (z-FA-FMK readily inhibits anti-CD3-induced human T cell proliferation, whereas the analogue benzyloxycarbonyl-phenylalanine-alanine-diazomethyl ketone (z-FA-DMK had no effect. In contrast, benzyloxycarbonyl-phenylalanine-alanine-chloromethyl ketone (z-FA-CMK was toxic. The inhibition of T cell proliferation mediated by z-FA-FMK requires not only the FMK moiety, but also the benzyloxycarbonyl group at the N-terminal, suggesting some degree of specificity in z-FA-FMK-induced inhibition of primary T cell proliferation. We showed that z-FA-FMK treatment leads to a decrease in intracellular glutathione (GSH with a concomitant increase in reactive oxygen species (ROS levels in activated T cells. The inhibition of anti-CD3-induced T cell proliferation mediated by z-FA-FMK was abolished by the presence of low molecular weight thiols such as GSH, N-acetylcysteine (NAC and L-cysteine, whereas D-cysteine which cannot be metabolised to GSH has no effect. The inhibition of anti-CD3-induced up-regulation of CD25 and CD69 expression mediated by z-FA-FMK was also attenuated in the presence of exogenous GSH. Similar to cell proliferation, GSH, NAC and L-cysteine but not D-cysteine, completely restored the processing of caspase-8 and caspase-3 to their respective subunits in z-FA-FMK-treated activated T cells. Our collective results demonstrated that the inhibition of T cell activation and proliferation mediated by z-FA-FMK is due to oxidative stress via the depletion of GSH.

  20. Decadal Variations of the Western Subarctic Gyre and Main Pycnocline Depth due to Wind Stress Change in the Northern North Pacific

    Science.gov (United States)

    Nagano, A.; Wakita, M.

    2017-12-01

    From the late 1990s to the early 2000s, the western subarctic gyre of the North Pacific, a cyclonic circulation in the western subarctic region, shrank northward associated with a decadal increase of sea surface height (SSH). This gyre change displaced the main pycnocline (halocline) downward and is expected to contribute to the deepening of the overlying temperature minimum layer. This is considered to affect the biogeochemical conditions in the western subarctic region, where is known as substantially slow ocean acidification region. In this study, on the basis of wind stress field data in the subpolar region (40˚N—54˚N, 160˚E—135˚W) during 1979—2014 provided by U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis, we estimated the variation in SSH, solving the vorticity gradient equation on the beta plane. Decadal increase in SSH at Station K2 (47˚N, 160˚E), representative point of the western subarctic region, was well produced by the calculation, and the correlation coefficient with altimetric SSH exceeds 0.6. The calculated SSH variation consists of the variations due to the barotropic and baroclinic Rossby wave modes. The gyre shrinkage is found to be caused primarily by the barotropic response to the wind change in the whole subpolar region and secondary by the first baroclinic response. Meanwhile, the decadal deepening of the main pycnocline at K2 is attributed to the baroclinic responses of the higher (second, third, and fourth) vertical modes to the local wind change.

  1. Gentilly-2 NPP - Concrete aging effects on long term pre-stress losses and propagation of concrete cracking due to pressure testing

    International Nuclear Information System (INIS)

    Gocevski, V.

    2011-01-01

    This paper presents the results of the study intended to evaluate the post-tension long term losses and propagation of cracks in the envelope of Gentilly-2 Nuclear Power Plant reactor building. The numerical simulation of concrete, that takes into account elastic as well as inelastic strains due to loading, shrinkage strains due to drying or cooling and inelastic strains from alkali-aggregate reaction (AAR) related swelling, is explained. The simultaneous contribution of AAR, shrinkage and creep, are simulated using an enhanced elastic-plastic constitutive relation. The nonlinear relations are validated by comparing the numerically calculated strains with strain measurements from the extensometers placed in the concrete during the construction of the envelope. The post-tension losses/gains are evaluated for the vertical as well as horizontal cables. Also included is the result of pull-out test conducted on sample beam cast at the time of the reactor building construction with the same concrete mix, post-tension cable and force. Structural behaviour of the beam is simulated over the same period of time as the reactor building envelope. The test results are used also to calibrate the numerical model. The paper also includes discussion of the results obtained from the simulation of a standard internal high pressure test (145 kPa). The behavior of the reactor building envelope, prior to applied pressure, during the test and for the period of several months after the testing was simulated using an advanced numerical model and the results (strains) were compared with measured values. It was found that this method may be used as an approximate procedure for evaluation of post-tension losses/gains and assessment of propagation of cracking visible on the outside surfaces of the confinement building. In addition, a discussion of the negative effect of high post-tension on the air tightness of the confinement building of Gentilly-2. The comparison is made between the post

  2. Gentilly-2 NPP - Concrete aging effects on long term pre-stress losses and propagation of concrete cracking due to pressure testing

    Energy Technology Data Exchange (ETDEWEB)

    Gocevski, V. [Hydro-Quebe (Canada)

    2011-07-01

    This paper presents the results of the study intended to evaluate the post-tension long term losses and propagation of cracks in the envelope of Gentilly-2 Nuclear Power Plant reactor building. The numerical simulation of concrete, that takes into account elastic as well as inelastic strains due to loading, shrinkage strains due to drying or cooling and inelastic strains from alkali-aggregate reaction (AAR) related swelling, is explained. The simultaneous contribution of AAR, shrinkage and creep, are simulated using an enhanced elastic-plastic constitutive relation. The nonlinear relations are validated by comparing the numerically calculated strains with strain measurements from the extensometers placed in the concrete during the construction of the envelope. The post-tension losses/gains are evaluated for the vertical as well as horizontal cables. Also included is the result of pull-out test conducted on sample beam cast at the time of the reactor building construction with the same concrete mix, post-tension cable and force. Structural behaviour of the beam is simulated over the same period of time as the reactor building envelope. The test results are used also to calibrate the numerical model. The paper also includes discussion of the results obtained from the simulation of a standard internal high pressure test (145 kPa). The behavior of the reactor building envelope, prior to applied pressure, during the test and for the period of several months after the testing was simulated using an advanced numerical model and the results (strains) were compared with measured values. It was found that this method may be used as an approximate procedure for evaluation of post-tension losses/gains and assessment of propagation of cracking visible on the outside surfaces of the confinement building. In addition, a discussion of the negative effect of high post-tension on the air tightness of the confinement building of Gentilly-2. The comparison is made between the post

  3. UEffect of acute sleep deprivation on concentration and mood states with a controlled effect of experienced stress

    Directory of Open Access Journals (Sweden)

    Tanja Kajtna

    2011-05-01

    Conclusions: As previous studies have shown, mood changes rather than decreased concentration occur after acute sleep deprivation – cognitive abilities seem to be more resistant to sleep deprivation. Further studies with longer sleep deprivation should show how long it takes to disrupt our concentration and higher cognitive abilities.

  4. Differential determination of perceived stress in medical students and high-school graduates due to private and training-related stressors

    Science.gov (United States)

    Herrmann–Werner, Anne; Keifenheim, Katharina Eva; Loda, Teresa; Bugaj, Till Johannes; Nikendei, Christoph; Lammerding–Köppel, Maria; Zipfel, Stephan; Junne, Florian

    2018-01-01

    Objective Numerous studies from diverse contexts have confirmed high stress levels and stress-associated health impairment in medical students. This study aimed to explore the differential association of perceived stress with private and training-related stressors in medical students according to their stage of medical education. Methods Participants were high-school graduates who plan to study medicine and students in their first, third, sixth, or ninth semester of medical school or in practical medical training. The self-administered questionnaire included items addressing demographic information, the Perceived Stress Questionnaire, and items addressing potential private and training-related stressors. Results Results confirmed a substantial burden of perceived stress in students at different stages of their medical education. In particular, 10–28% of students in their third or ninth semesters of medical school showed the highest values for perceived stress. Training-related stressors were most strongly associated with perceived stress, although specific stressors that determined perceived stress varied across different stages of students’ medical education. High-school graduates highly interested in pursuing medical education showed specific stressors similar to those of medical students in their third, sixth, or ninth semesters of medical school, as well as stress structures with heights of general stress rates similar to those of medical students at the beginning of practical medical training. Conclusions High-school graduates offer new, interesting information about students’ fears and needs before they begin medical school. Medical students and high-school graduates need open, comprehensive information about possible stressors at the outset of and during medical education. Programmes geared toward improving resilience behaviour and teaching new, functional coping strategies are recommended. PMID:29385180

  5. Differential determination of perceived stress in medical students and high-school graduates due to private and training-related stressors.

    Science.gov (United States)

    Erschens, Rebecca; Herrmann-Werner, Anne; Keifenheim, Katharina Eva; Loda, Teresa; Bugaj, Till Johannes; Nikendei, Christoph; Lammerding-Köppel, Maria; Zipfel, Stephan; Junne, Florian

    2018-01-01

    Numerous studies from diverse contexts have confirmed high stress levels and stress-associated health impairment in medical students. This study aimed to explore the differential association of perceived stress with private and training-related stressors in medical students according to their stage of medical education. Participants were high-school graduates who plan to study medicine and students in their first, third, sixth, or ninth semester of medical school or in practical medical training. The self-administered questionnaire included items addressing demographic information, the Perceived Stress Questionnaire, and items addressing potential private and training-related stressors. Results confirmed a substantial burden of perceived stress in students at different stages of their medical education. In particular, 10-28% of students in their third or ninth semesters of medical school showed the highest values for perceived stress. Training-related stressors were most strongly associated with perceived stress, although specific stressors that determined perceived stress varied across different stages of students' medical education. High-school graduates highly interested in pursuing medical education showed specific stressors similar to those of medical students in their third, sixth, or ninth semesters of medical school, as well as stress structures with heights of general stress rates similar to those of medical students at the beginning of practical medical training. High-school graduates offer new, interesting information about students' fears and needs before they begin medical school. Medical students and high-school graduates need open, comprehensive information about possible stressors at the outset of and during medical education. Programmes geared toward improving resilience behaviour and teaching new, functional coping strategies are recommended.

  6. Effect of transportation stress on heat shock protein 70 concentration and mRNA expression in heart and kidney tissues and serum enzyme activities and hormone concentrations of pigs.

    Science.gov (United States)

    Yu, Hong; Bao, En-Dong; Zhao, Ru-Qian; Lv, Qiong-Xia

    2007-11-01

    To determine the enzymatic and hormonal responses, heat shock protein 70 (Hsp70) production, and Hsp70 mRNA expression in heart and kidney tissues of transport-stressed pigs. 24 pigs (mean weight, 20 +/- 1 kg). Pigs were randomly placed into groups of 12 each. One group was transported for 2 hours. The other group was kept under normal conditions and used as control pigs. Sera were used to detect triiodothyronine, thyroxine, and cortisol concentrations and alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities. The heart and kidneys of anesthetized pigs were harvested and frozen in liquid nitrogen for quantification of Hsp70 and Hsp70 mRNA. No significant differences were detected in serum alanine aminotransferase activity and triiodothyronine and cortisol concentrations between groups; however, the serum creatine kinase and aspartate aminotransferase activities and thyroxine concentrations were higher in transported pigs. Densitometric readings of western blots revealed that the amount of Hsp70 in heart and kidney tissues was significantly higher in transported pigs, compared with control pigs. Results of fluorescence quantitative real-time PCR assay revealed that the Hsp70 mRNA transcription in heart tissue, but not kidney tissue, was significantly higher in transported pigs, compared with control pigs. Transportation imposed a severe stress on pigs that was manifested as increased serum activities of aspartate aminotransferase and creatine kinase and increased amounts of Hsp70 and Hsp70 mRNA expression in heart and kidney tissues. Changes in serum enzyme activities were related to the tissue damage of transport-stressed pigs.

  7. Effect of Plant Growth Promoting Rhizobacteria on the Concentration and Uptake of Macro Nutrients by Corn in a Cd-contaminated Calcareous Soil under Drought Stress

    Directory of Open Access Journals (Sweden)

    shahrzad karami

    2017-02-01

    Full Text Available Introduction: Heavy metals such as cadmium (Cd are found naturally in soils, but their amount can be changed by human activities. The study of the uptake and accumulation of heavy metals by plants is done in order to prevent their threats on human and animal’s health.Cadmium is a toxic element for living organisms. Cadmium competes with many of nutrients to be absorbed by the plant and interferes with their biological roles. Water stress affects the cell structure and the food is diverted from its normal metabolic pathway. It also reduces the availability and uptake of nutrients by the plant. One reason for the reduction of plant growth under drought stress is the accumulation of ethylene in plants. There are ways to mitigate the negative effects of drought stress that one of which is the use of Plant Growth Promoting Rhizobacteria(PGPRs to increasing the availability of nutrients. Soil beneficial bacteria play an important role in the biological cycles and have been used to increase plant health and soil fertility over the past few decades.The aim of this study was to investigate theeffect of PGPRson the concentration and uptake of macro nutrients by corn in a Cd-contaminated calcareous soil under drought stress. Materials and Methods: A greenhouse factorial experiment was conducted in a completely randomized design with three replications. The treatments were two levels of bacteria (with and without bacteria, four levels of Cd (5, 10, 20, and 40 mg kg-1, and three levels of drought stress (without stress, 80, and 65% of field capacity. The pots were filled with 3 kg of treated soil. Cd was treated as its sulfate salt in amounts of 5, 10, 20, and 40 mg kg-1. The soil was mixed uniformly with 150 mg N kg-1 as urea, 20 mg P kg-1 as Ca (H2PO42, 5 mg Fe kg-1 as Fe-EDDHA and 10, 10 and 2.5 mg Zn, Mn and Cu kg-1, respectively as their sulfate salt in order to meet plant needs for these nutrients. Six seeds of Zea mays (var. HIDO were planted at

  8. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    International Nuclear Information System (INIS)

    Sandoval-Pineda, J M; Garcia-Lira, J; Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R

    2009-01-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  9. Numerical and experimental evaluation of the residual stress relaxation and the influence zone due to application of the crack compliance method

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Pineda, J M; Garcia-Lira, J [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de IngenierIa Mecanica y Electrica (ESIME), Unidad profesional, Azcapotzalco, Av. de las Granjas No. 682, Col. Sta. Catarina Azcapotzalco, C.P. 02550, Mexico D.F. Mexico (Mexico); Urriolagoitia-Sosa, G; Urriolagoitia-Calderon, G; Hernandez-Gomez, L H; Beltran-Fernandez, J A; RodrIguez-Martinez, R, E-mail: jsandovalp@ipn.m, E-mail: guiurri@hotmail.co [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion (SEPI), Escuela Superior de IngenierIa Mecanica y Electrica (ESIME). Edificio 5. 2do Piso, Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, C.P. 07738, Mexico, D.F. Mexico (Mexico)

    2009-08-01

    This paper presents the results concerning an evaluation of the crack compliance method. The research was focused on the relaxation caused by a cut induced to obtain the data required to calculate the residual stress field. The main objective in this research is to establish the optimum place to cut in a specimen that has suffered a failure and how extended is the zone of relaxed stresses. It has been recognized that a crack vanishes the beneficial or detrimental effects of the residual stress fields. This research has been performed in a numerical and experimental way, so results can be compared and FEM on this topic can be assessed.

  10. Transient thermal stresses in a transversely isotropic finite composite hollow circular cylinder due to arbitrary surface heat-generations and surrounding temperatures

    International Nuclear Information System (INIS)

    Sugano, Y.

    1981-01-01

    An exact solution is given for the temperature distribution, the thermal stresses and displacements in a transversely isotropic finite composite hollow circular cylinder composed of two distinct cylindrical laminae. The temperature field is determined by using of the Laplace transform and the finite Fourier-cosine transform, respectively, with respect to time and axial coordinate included in the governing equation and the associated thermal stresses and displacements are analvsed by the use of a set of stress functions closely related to the Love's function valid for the axisymmetric isothermal problem of isotropic bodies. (orig.)

  11. Differences in the cyclic deformation behaviour of quenched and tempered steel 42 CrMo 4 (AISI 4140) due to stress- and strain-control

    International Nuclear Information System (INIS)

    Schulze, V.; Lang, K.-H.; Voehringer, O.; Macherauch, E.

    1998-01-01

    Cyclic stress-strain-curves and Manson-Coffin-plots of quenched and tempered steel 42 CrMo 4 (AISI 4140) strongly depend on whether they are determined under stress- or total-strain-control. At total-strain-controlled experiments, this is caused on the one hand by comparatively high initial stress-amplitudes which lead to distinctive cyclic work softening. On the other hand, the occuring differences in the evolution of inhomogeneous deformation patterns at both types of loading, which can be recorded by means of photoelasticity and microscopy, lead to differently distributed plastic deformations and to different integral values of plastic strain. (orig.)

  12. Stress concentrations at structural discontinuities in active fault zones in the western United States: Implications for permeability and fluid flow in geothermal fields

    Science.gov (United States)

    Siler, Drew; Hinz, Nicholas H.; Faulds, James E.

    2018-01-01

    Slip can induce concentration of stresses at discontinuities along fault systems. These structural discontinuities, i.e., fault terminations, fault step-overs, intersections, bends, and other fault interaction areas, are known to host fluid flow in ore deposition systems, oil and gas reservoirs, and geothermal systems. We modeled stress transfer associated with slip on faults with Holocene-to-historic slip histories at the Salt Wells and Bradys geothermal systems in western Nevada, United States. Results show discrete locations of stress perturbation within discontinuities along these fault systems. Well field data, surface geothermal manifestations, and subsurface temperature data, each a proxy for modern fluid circulation in the fields, indicate that geothermal fluid flow is focused in these same areas where stresses are most highly perturbed. These results suggest that submeter- to meter-scale slip on these fault systems generates stress perturbations that are sufficiently large to promote slip on an array of secondary structures spanning the footprint of the modern geothermal activity. Slip on these secondary faults and fractures generates permeability through kinematic deformation and allows for transmission of fluids. Still, mineralization is expected to seal permeability along faults and fractures over time scales that are generally shorter than either earthquake recurrence intervals or the estimated life span of geothermal fields. This suggests that though stress perturbations resulting from fault slip are broadly important for defining the location and spatial extent of enhanced permeability at structural discontinuities, continual generation and maintenance of flow conduits throughout these areas are probably dependent on the deformation mechanism(s) affecting individual structures.

  13. Microparticle content of platelet concentrates is predicted by donor microparticles and is altered by production methods and stress

    DEFF Research Database (Denmark)

    Maurer-Spurej, Elisabeth; Larsen, Rune; Labrie, Audrey

    2016-01-01

    In circulation, shedding of microparticles from a variety of viable cells can be triggered by pathological activation of inflammatory processes, by activation of coagulation or complement systems, or by physical stress. Elevated microparticle content (MPC) in donor blood might therefore indicate...... a clinical condition of the donor which, upon transfusion, might affect the recipient. In blood products, elevated MPC might also represent product stress. Surprisingly, the MPC in blood collected from normal blood donors is highly variable, which raises the question whether donor microparticles are present...... in-vivo and transfer into the final blood component, and how production methods and post-production processing might affect the MPC. We measured MPC using ThromboLUX in (a) platelet-rich plasma (PRP) of 54 apheresis donors and the corresponding apheresis products, (b) 651 apheresis and 646 pooled...

  14. Coupling effects of chemical stresses and external mechanical stresses on diffusion

    International Nuclear Information System (INIS)

    Xuan Fuzhen; Shao Shanshan; Wang Zhengdong; Tu Shantung

    2009-01-01

    Interaction between diffusion and stress fields has been investigated extensively in the past. However, most of the previous investigations were focused on the effect of chemical stress on diffusion due to the unbalanced mass transport. In this work, the coupling effects of external mechanical stress and chemical stress on diffusion are studied. A self-consistent diffusion equation including the chemical stress and external mechanical stress gradient is developed under the framework of the thermodynamic theory and Fick's law. For a thin plate subjected to unidirectional tensile stress fields, the external stress coupled diffusion equation is solved numerically with the help of the finite difference method for one-side and both-side charging processes. Results show that, for such two types of charging processes, the external stress gradient will accelerate the diffusion process and thus increase the value of concentration while reducing the magnitude of chemical stress when the direction of diffusion is identical to that of the stress gradient. In contrast, when the direction of diffusion is opposite to that of the stress gradient, the external stress gradient will obstruct the process of solute penetration by decreasing the value of concentration and increasing the magnitude of chemical stress. For both-side charging process, compared with that without the coupling effect of external stress, an asymmetric distribution of concentration is produced due to the asymmetric mechanical stress field feedback to diffusion.

  15. Risk markers of all-cause and diagnosis-specific disability pension--a prospective cohort study of individuals sickness absent due to stress-related mental disorders

    DEFF Research Database (Denmark)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2014-01-01

    BACKGROUND: Stress-related mental disorders rank among the leading causes of sickness absence in several European countries. The aim of this study was to investigate predictors of all-cause and diagnosis-specific disability pension in sickness absentees with stress-related mental disorders. METHO....... The variation in the effect of risk markers with regard to age and diagnosis of disability pension speaks in favour of the importance of a person-centered approach in treatment and rehabilitation....

  16. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Paolla Gabrielle Nascimento Novais

    Full Text Available ABSTRACT Objective: to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. Method: random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group. The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. Results: the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (p<0.001, which in turn proved that there was a reduction in the levels of stress after the application of the relaxation practic-es. Conclusion: the progressive muscle relaxation activities contributed to the reduction in stress levels for multiple sclerosis suffers and thus can be used in nursing for patients. Clinical Trials Identifier: NCT 02673827.

  17. Hypothalamic kappa opioid receptor mediates both diet-induced and melanin concentrating hormone-induced liver damage through inflammation and endoplasmic reticulum stress.

    Science.gov (United States)

    Imbernon, Monica; Sanchez-Rebordelo, Estrella; Romero-Picó, Amparo; Kalló, Imre; Chee, Melissa J; Porteiro, Begoña; Al-Massadi, Omar; Contreras, Cristina; Fernø, Johan; Senra, Ana; Gallego, Rosalia; Folgueira, Cintia; Seoane, Luisa M; van Gestel, Margriet; Adan, Roger A; Liposits, Zsolt; Dieguez, Carlos; López, Miguel; Nogueiras, Ruben

    2016-10-01

    The opioid system is widely known to modulate the brain reward system and thus affect the behavior of humans and other animals, including feeding. We hypothesized that the hypothalamic opioid system might also control energy metabolism in peripheral tissues. Mice lacking the kappa opioid receptor (κOR) and adenoviral vectors overexpressing or silencing κOR were stereotaxically delivered in the lateral hypothalamic area (LHA) of rats. Vagal denervation was performed to assess its effect on liver metabolism. Endoplasmic reticulum (ER) stress was inhibited by pharmacological (tauroursodeoxycholic acid) and genetic (overexpression of the chaperone glucose-regulated protein 78 kDa) approaches. The peripheral effects on lipid metabolism were assessed by histological techniques and western blot. We show that in the LHA κOR directly controls hepatic lipid metabolism through the parasympathetic nervous system, independent of changes in food intake and body weight. κOR colocalizes with melanin concentrating hormone receptor 1 (MCH-R1) in the LHA, and genetic disruption of κOR reduced melanin concentrating hormone-induced liver steatosis. The functional relevance of these findings was given by the fact that silencing of κOR in the LHA attenuated both methionine choline-deficient, diet-induced and choline-deficient, high-fat diet-induced ER stress, inflammation, steatohepatitis, and fibrosis, whereas overexpression of κOR in this area promoted liver steatosis. Overexpression of glucose-regulated protein 78 kDa in the liver abolished hypothalamic κOR-induced steatosis by reducing hepatic ER stress. This study reveals a novel hypothalamic-parasympathetic circuit modulating hepatic function through inflammation and ER stress independent of changes in food intake or body weight; these findings might have implications for the clinical use of opioid receptor antagonists. (Hepatology 2016;64:1086-1104). © 2016 The Authors. (Hepatology published by Wiley Periodicals, Inc., on

  18. Improvement in accuracy of the measurements of residual stresses due to circumferential welds in thin-walled pipe using Rayleigh wave method

    International Nuclear Information System (INIS)

    Akhshik, Siamak; Moharrami, Rasool

    2009-01-01

    To achieve an acceptable safety in many industrial applications such as nuclear power plants and power generation, it is extremely important to gain an understanding of the magnitudes and distributions of the residual stresses in a pipe formed by joining two sections with a girth butt weld. Most of the methods for high-accuracy measurement of residual stress are destructive. These destructive measurement methods cannot be applied to engineering systems and structures during actual operation. In this paper, we present a method based on the measurement of ultrasonic Rayleigh wave velocity variations versus the stress state for nondestructive evaluation of residual stress in dissimilar pipe welded joint. We show some residual stress profile obtained by this method. These are then compared with other profiles determined using a semi-destructive technique (hole-drilling) that makes it possible to check our results. According to the results, we also present a new method for adjusting the ultrasonic measurements to improve the agreement with the results obtained from other techniques.

  19. Effects of fasting on plasma catecholamine, corticosterone and glucose concentrations under basal and stress conditions in individual rats

    NARCIS (Netherlands)

    de Boer, S.F.; Koopmans, S.J.; Slangen, J L; Van der Gugten, J

    Plasma noradrenaline (NA), adrenaline (A), corticosterone (CS) and glucose concentrations were determined in blood sampled via a cardiac catheter from freely moving male rats under ad lib fed and 24 hr food deprived conditions using a repeated measures within-subject design. Resting plasma NA and

  20. The effect of acute exercise and psychosocial stress on fine motor skills and testosterone concentration in the saliva of high school students.

    Directory of Open Access Journals (Sweden)

    Mirko Wegner

    Full Text Available Little is known about the influence of different stressors on fine motor skills, the concentration of testosterone (T, and their interaction in adolescents. Therefore, 62 high school students aged 14-15 years were randomly assigned to two experimental groups (exercise, psychosocial stress and a control group. Exercise stress was induced at 65-75% of the maximum heart rate by running for 15 minutes (n = 24. Psychosocial stress was generated by an intelligence test (HAWIK-IV, which was uncontrollable and characterized by social-evaluative-threat to the students (n = 21. The control group followed was part of a regular school lesson with the same duration (n = 28. Saliva was collected after a normal school lesson (pre-test as well as after the intervention/control period (post-test and was analyzed for testosterone. Fine motor skills were assessed pre- and post-intervention using a manual dexterity test (Flower Trail from the Movement Assessment Battery for Children-2. A repeated measure ANCOVA including gender as a covariate revealed a significant group by test interaction, indicating an increase in manual dexterity only for the psychosocial stress group. Correlation analysis of all students shows that the change of testosterone from pre- to post-test was directly linked (r = -.31, p = .01 to the changes in manual dexterity performance. Participants showing high increases in testosterone from pre- to post-test made fewer mistakes in the fine motor skills task. Findings suggest that manual dexterity increases when psychosocial stress is induced and that improvement of manual dexterity performance corresponds with the increase of testosterone.

  1. Oxidative stress mediated toxicity of TiO2 nanoparticles after a concentration and time dependent exposure of the aquatic macrophyte Hydrilla verticillata.

    Science.gov (United States)

    Spengler, Annette; Wanninger, Lena; Pflugmacher, Stephan

    2017-09-01

    The present study focused on oxidative stress effects in the aquatic macrophyte Hydrilla verticillata after exposure to titanium dioxide nanoparticles (TiO 2 -NPs). Experiments were conducted with different TiO 2 -NPs and concentrations (0.1 mg/L and 10 mg/L) in a time-dependent manner (0 h, 24 h, 48 h, 96 h, 168 h). To assess various levels of the oxidative stress response in H. verticillata, the level of hydrogen peroxide (H 2 O 2 ), the ratio of reduced to oxidized glutathione (GSH/GSSG), and activities of the antioxidative enzymes catalase (CAT) and glutathione reductase (GR) were evaluated. Study results imply oxidative stress effects after TiO 2 -NP exposure as adaptations in plant metabolism became apparent to counteract increased ROS formation. All TiO 2 -NPs caused elevated activities of the enzymes CAT and GR. Moreover, decreased ratios of GSH/GSSG indicated an activation of GSH-dependent pathways counteracting ROS formation. Plants exposed to a bulk-sized control revealed a size-dependent influence on the antioxidative stress response. As H 2 O 2 level increases were solely detected after exposure to 10 mg/L TiO 2 -NPs and nano-exposed plants showed normalization in its antioxidative stress response after 168h of exposure, it can be suggested that macrophytes are able to cope with currently predicted low-level exposures to TiO 2 -NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Parameter-free method for the shape optimization of stiffeners on thin-walled structures to minimize stress concentration

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Shibutan, Yoji [Osaka University, Osaka (Japan); Shimoda, Masatoshi [Toyota Technological Institute, Nagoya (Japan)

    2015-04-15

    This paper presents a parameter-free shape optimization method for the strength design of stiffeners on thin-walled structures. The maximum von Mises stress is minimized and subjected to the volume constraint. The optimum design problem is formulated as a distributed-parameter shape optimization problem under the assumptions that a stiffener is varied in the in-plane direction and that the thickness is constant. The issue of nondifferentiability, which is inherent in this min-max problem, is avoided by transforming the local measure to a smooth differentiable integral functional by using the Kreisselmeier-Steinhauser function. The shape gradient functions are derived by using the material derivative method and adjoint variable method and are applied to the H{sup 1} gradient method for shells to determine the optimal free-boundary shapes. By using this method, the smooth optimal stiffener shape can be obtained without any shape design parameterization while minimizing the maximum stress. The validity of this method is verified through two practical design examples.

  3. The effects of acute waterborne exposure to sublethal concentrations of molybdenum on the stress response in rainbow trout, Oncorhynchus mykiss.

    Directory of Open Access Journals (Sweden)

    Chelsea D Ricketts

    Full Text Available To determine if molybdenum (Mo is a chemical stressor, fingerling and juvenile rainbow trout (Oncorhynchus mykiss were exposed to waterborne sodium molybdate (0, 2, 20, or 1,000 mg l-1 of Mo and components of the physiological (plasma cortisol, blood glucose, and hematocrit and cellular (heat shock protein [hsp] 72, hsp73, and hsp90 in the liver, gills, heart, and erythrocytes and metallothionein [MT] in the liver and gills stress responses were measured prior to initiation of exposure and at 8, 24, and 96 h. During the acute exposure, plasma cortisol, blood glucose, and hematocrit levels remained unchanged in all treatments. Heat shock protein 72 was not induced as a result of exposure and there were no detectable changes in total hsp70 (72 and 73, hsp90, and MT levels in any of the tissues relative to controls. Both fingerling and juvenile fish responded with similar lack of apparent sensitivity to Mo exposure. These experiments demonstrate that exposure to waterborne Mo of up to 1,000 mg l(-1 did not activate a physiological or cellular stress response in fish. Information from this study suggests that Mo water quality guidelines for the protection of aquatic life are highly protective of freshwater fish, namely rainbow trout.

  4. Effect of Layer-Graded Bond Coats on Edge Stress Concentration and Oxidation Behavior of Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Ghosn, Louis J.; Miller, Robert A.

    1998-01-01

    Thermal barrier coating (TBC) durability is closely related to design, processing and microstructure of the coating Z, tn systems. Two important issues that must be considered during the design of a thermal barrier coating are thermal expansion and modulus mismatch between the substrate and the ceramic layer, and substrate oxidation. In many cases, both of these issues may be best addressed through the selection of an appropriate bond coat system. In this study, a low thermal expansion and layer-graded bond coat system, that consists of plasma-sprayed FeCoNiCrAl and FeCrAlY coatings, and a high velocity oxyfuel (HVOF) sprayed FeCrAlY coating, is developed to minimize the thermal stresses and provide oxidation resistance. The thermal expansion and oxidation behavior of the coating system are also characterized, and the strain isolation effect of the bond coat system is analyzed using the finite element method (FEM). Experiments and finite element results show that the layer-graded bond coat system possesses lower interfacial stresses. better strain isolation and excellent oxidation resistance. thus significantly improving the coating performance and durability.

  5. The Effects of Acute Waterborne Exposure to Sublethal Concentrations of Molybdenum on the Stress Response in Rainbow Trout, Oncorhynchus mykiss

    Science.gov (United States)

    Ricketts, Chelsea D.; Bates, William R.; Reid, Scott D.

    2015-01-01

    To determine if molybdenum (Mo) is a chemical stressor, fingerling and juvenile rainbow trout (Oncorhynchus mykiss) were exposed to waterborne sodium molybdate (0, 2, 20, or 1,000 mg l-1 of Mo) and components of the physiological (plasma cortisol, blood glucose, and hematocrit) and cellular (heat shock protein [hsp] 72, hsp73, and hsp90 in the liver, gills, heart, and erythrocytes and metallothionein [MT] in the liver and gills) stress responses were measured prior to initiation of exposure and at 8, 24, and 96 h. During the acute exposure, plasma cortisol, blood glucose, and hematocrit levels remained unchanged in all treatments. Heat shock protein 72 was not induced as a result of exposure and there were no detectable changes in total hsp70 (72 and 73), hsp90, and MT levels in any of the tissues relative to controls. Both fingerling and juvenile fish responded with similar lack of apparent sensitivity to Mo exposure. These experiments demonstrate that exposure to waterborne Mo of up to 1,000 mg l-1 did not activate a physiological or cellular stress response in fish. Information from this study suggests that Mo water quality guidelines for the protection of aquatic life are highly protective of freshwater fish, namely rainbow trout. PMID:25629693

  6. Three Dimensional Parametric Analyses on Effect of Fibre Orientation for Stress Concentration Factor in Fibrous Composite Cantilever Plate with Central Circular Hole under Transverse Loading

    Directory of Open Access Journals (Sweden)

    Nitin Jain

    2012-10-01

    Full Text Available Normal 0 false false false EN-IN X-NONE X-NONE ABSTRACT: A number of analytical and numerical techniques are available for the two dimensional study of stress concentration around the hole(s in isotropic and composite plates subjected to in-plane or transverse loading conditions. The information on the techniques for three dimensional analyses of stress concentration factor (SCF around the hole in isotropic and composite plates subjected to transverse loading conditions is, however, limited. The present work emphasizes on the effect of fibre orientation (q on the stress concentration factor in fibrous composite plates with central circular hole under transverse static loading condition. The work is carried out for cantilever fibrous composite plates. The effects of thickness -to- width (T/A and diameter-to-width (D/A ratios upon SCF at different fibre orientation are studied. Plates of four different composite materials were considered for hole analysis in order to determine the sensitivity of SCF with elastic constants. Deflections in transverse direction were calculated and analysed. All results are presented in graphical form and discussed. The finite element formulation and its analysis were carried out using ANSYS package.ABSTRAK: Terdapat pelbagai teknik analitikal dan numerical untuk kajian tumpuan tegasan dua dimensi di sekeliling lubang-lubang dalam komposit isotropik dan plat pada satah atau keadaan bebanan melintang. Bagaimanapun, maklumat mengenai kaedah analisis tiga dimensi untuk faktor ketumpatan tegasan (SCF sekitar lubang dalam komposit isotropik dan plat pada keadaan bebanan melintang adalah terhad. Kertas ini menekankan kesan orientasi gentian (q pada faktor tumpuan tegasan dalam komposit plat bergentian dengan lubang berpusat di bawah keadaan bebanan melintang. Kajian ini dilkukan untuk cantilever plat komposit bergentian. Kesan ketebalan terhadap kelebaran plat (T/A dan diameter terhadap kelebaran komposit (D/A dengan SCF

  7. Enhancement of BDNF Concentration and Restoration of the Hypothalamic-Pituitary-Adrenal Axis Accompany Reduced Depressive-Like Behaviour in Stressed Ovariectomised Rats Treated with Either Tualang Honey or Estrogen

    Directory of Open Access Journals (Sweden)

    Badriya Al-Rahbi

    2014-01-01

    Full Text Available A possible interaction between glucocorticoids and estrogen-induced increases in brain-derived-neurotrophic factor (BDNF expression in enhancing depressive-like behaviour has been documented. Here we evaluated the effects of Tualang honey, a phytoestrogen, and 17β-estradiol (E2 on the depressive-like behaviour, stress hormones, and BDNF concentration in stressed ovariectomised (OVX rats. The animals were divided into six groups: (i nonstressed sham-operated control, (ii stressed sham-operated control, (iii nonstressed OVX, (iv stressed OVX, (v stressed OVX treated with E2 (20 μg daily, sc, and (vi stressed OVX treated with Tualang honey (0.2 g/kg body weight daily, orally. Two months after surgery, the animals were subjected to social instability stress procedure followed by forced swimming test. Struggling time, immobility time, and swimming time were scored. Serum adrenocorticotropic hormone (ACTH and corticosterone levels, and the BDNF concentration were determined using commercially available ELISA kits. Stressed OVX rats displayed increased depressive-like behaviour with significantly increased serum ACTH and corticosterone levels, while the BDNF concentration was significantly decreased compared to other experimental groups. These changes were notably reversed by both E2 and Tualang honey. In conclusion, both Tualang honey and E2 mediate antidepressive-like effects in stressed OVX rats, possibly acting via restoration of hypothalamic-pituitary-adrenal axis and enhancement of the BDNF concentration.

  8. Concentration-elastic-stress instabilities in the distribution of ions and neutral particles in the insulator layer at the semiconductor surface

    International Nuclear Information System (INIS)

    Gol'dman, E. I.

    2006-01-01

    Mobile impurities in the form of ions and neutral associations are present in the insulator films that isolate the semiconductor from the metal electrode. If temperatures and the polarizing electric field are sufficiently high, impurities concentrate at the insulator-semiconductor interface where they exchange electrons with the semiconductor. It is shown that the pairwise interaction of particles via the field of elastic stresses caused by the concentration-related expansion of the insulator can give rise to an instability in the impurity distribution that is uniform over the contact. The stationary small-scale ordering of the particles over the contact of the insulator with the semiconductor arises in the solution of point defects, which is accompanied by annular flows of the particles

  9. Work-Home Interference, Perceived Total Workload, and the Risk of Future Sickness Absence Due to Stress-Related Mental Diagnoses Among Women and Men: a Prospective Twin Study.

    Science.gov (United States)

    Svedberg, Pia; Mather, Lisa; Bergström, Gunnar; Lindfors, Petra; Blom, Victoria

    2018-02-01

    Work-home interference has been proposed as an important explanation for sickness absence (SA). Previous studies show mixed results, have not accounted for familial factors (genetics and shared everyday environment), or investigated diagnosis specific SA. The aim was to study whether work-home interference and perceived total workload predict SA due to stress-related mental diagnoses, or SA due to other mental diagnoses, among women and men, when adjusting for various confounders and familial factors. This study included 11,916 twins, 19-47 years (49% women). Data on work-to-home and home-to-work conflicts, perceived total workload, and relevant confounders were derived from a 2005 survey, and national register data on SA spells until 2013 were obtained. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Discordant twin pair design was applied to adjust for familial factors. Each one unit increase in work-to-home and home-to-work conflicts, and perceived total workload was associated with higher odds for SA due to stress-related mental diagnoses and to SA due to other mental diagnoses among women, when adjusting for sociodemographic factors (ORs 1.15-1.31). Including health or familial factors, no associations remained. For men, each one unit increase in work-to-home conflicts was associated with higher odds for SA due to stress-related diagnoses (ORs 1.23-1.35), independently of confounders. Work-to-home conflict was independently associated with future SA due to stress-related diagnoses among men only. Health- and work-related factors seem to be important confounders when researching work-home interference, perceived total workload, and SA. Not including such confounders involves risking drawing incorrect conclusions. Further studies are needed to confirm sex differences and whether genetic factors are important for the associations studied.

  10. Activation of the protein kinase C1 pathway upon continuous heat stress in S.cerevisiae is triggered by an increase in osmolarity due to trehalose accumulation.

    NARCIS (Netherlands)

    Mensonides, F.I.C.; Brul, S.; Klis, F.M.; Hellingwerf, K.J.; Teixeira De Mattos, M.J.

    2005-01-01

    This paper reports on physiological and molecular responses of Saccharomyces cerevisiae to heat stress conditions. We observed that within a very narrow range of culture temperatures, a shift from exponential growth to growth arrest and ultimately to cell death occurred. A detailed analysis was

  11. Oxidation of water to hydrogen peroxide at the rock-water interface due to stress-activated electric currents in rocks

    NARCIS (Netherlands)

    Balk, M.; Bose, M.; Ertem, G.; Rogoff, D.A.; Rothschild, L.J.; Freund, F.T.

    2009-01-01

    Common igneous and high-grade metamorphic rocks contain dormant defects, which release electronic charge carriers when stressed. Rocks thereby behave like a battery. The charge carriers of interest are defect electrons h¿, e.g. electronic states associated with O¿ in a matrix of O2¿. Known as

  12. Oxidation of water to hydrogen peroxide at the rock–water interface due to stress-activated electric currents in rocks

    NARCIS (Netherlands)

    Balk, M.; Bose, M.; Ertem, G.; Rogoff, D.A.; Rothschild, L.J.; Freund, F.T.

    2009-01-01

    Common igneous and high-grade metamorphic rocks contain dormant defects, which release electronic charge carriers when stressed. Rocks thereby behave like a battery. The charge carriers of interest are defect electrons h•, e.g. electronic states associated with O− in a matrix of O2−. Known as

  13. Predictors of suicidal behaviour in 36,304 individuals sickness absent due to stress-related mental disorders -- a Swedish register linkage cohort study

    DEFF Research Database (Denmark)

    Ishtiak-Ahmed, Kazi; Perski, Aleksander; Mittendorfer-Rutz, Ellenor

    2013-01-01

    BACKGROUND: Stress-related mental disorders (SRMD), which correspond to the diagnostic code F43 in the International Classification of Diseases, version 10, rank among the leading causes of sickness absence in several European countries. Despite the size of this health problem, research on risk...

  14. A novel transgenic mouse model of growth plate dysplasia reveals that decreased chondrocyte proliferation due to chronic ER stress is a key factor in reduced bone growth

    Directory of Open Access Journals (Sweden)

    Benedetta Gualeni

    2013-11-01

    Disease mechanisms leading to different forms of chondrodysplasia include extracellular matrix (ECM alterations and intracellular stress resulting in abnormal changes to chondrocyte proliferation and survival. Delineating the relative contribution of these two disease mechanisms is a major challenge in understanding disease pathophysiology in genetic skeletal diseases and a prerequisite for developing effective therapies. To determine the influence of intracellular stress and changes in chondrocyte phenotype to the development of chondrodysplasia, we targeted the expression of the G2320R mutant form of thyroglobulin to the endoplasmic reticulum (ER of resting and proliferating chondrocytes. Previous studies on this mutant protein have shown that it induces intracellular aggregates and causes cell stress and death in the thyroid gland. The expression and retention of this exogenous mutant protein in resting and proliferating chondrocytes resulted in a chronic cell stress response, growth plate dysplasia and reduced bone growth, without inducing any alterations to the architecture and organization of the cartilage ECM. More significantly, the decreased bone growth seemed to be the direct result of reduced chondrocyte proliferation in the proliferative zone of growth plates in transgenic mice, without transcriptional activation of a classical unfolded protein response (UPR or apoptosis. Overall, these data show that mutant protein retention in the ER of resting and proliferative zone chondrocytes is sufficient to cause disrupted bone growth. The specific disease pathways triggered by mutant protein retention do not necessarily involve a prototypic UPR, but all pathways impact upon chondrocyte proliferation in the cartilage growth plate.

  15. The association of subjective stress, urinary catecholamine concentrations and PC game room use and musculoskeletal disorders of the upper limbs in young male Koreans.

    Science.gov (United States)

    Kang, Jong-Won; Kim, Heon; Cho, Soo-Hun; Lee, Myung-Koo; Kim, Yong-Dae; Nan, Hong-Mei; Lee, Chul-Ho

    2003-06-01

    The use of PCs can cause health problems, including musculoskeletal disorders (MSDs) of the upper limbs. This study was performed to investigate whether using PCs in PC game rooms may induce MSDs of the upper limbs. 284 young male Koreans were included. A self-administered, structured questionnaire was used to gather information about game room use, perceived subjective stress, and the symptoms related to MSDs. Urinary concentrations of epinephrine, norepinephrine, and dopamine were measured in spot urine. The symptom prevalence of MSDs of the upper limbs increased according to the increase of the duration of game room use. The intensity of perceived subjective stress showed a significant dose-response relationship with the frequency of MSDs symptoms in neck and shoulder areas. However, the urinary level of catecholamines was not significantly correlated with the symptom prevalence of MSDs in the upper limbs. These findings suggest that using PCs in game rooms produce physical stress on the upper limbs, strong enough to induce MSDs.

  16. Comparison between micro- and nanosized copper oxide and water soluble copper chloride: interrelationship between intracellular copper concentrations, oxidative stress and DNA damage response in human lung cells.

    Science.gov (United States)

    Strauch, Bettina Maria; Niemand, Rebecca Katharina; Winkelbeiner, Nicola Lisa; Hartwig, Andrea

    2017-08-01

    Nano- and microscale copper oxide particles (CuO NP, CuO MP) are applied for manifold purposes, enhancing exposure and thus the potential risk of adverse health effects. Based on the pronounced in vitro cytotoxicity of CuO NP, systematic investigations on the mode of action are required. Therefore, the impact of CuO NP, CuO MP and CuCl 2 on the DNA damage response on transcriptional level was investigated by quantitative gene expression profiling via high-throughput RT-qPCR. Cytotoxicity, copper uptake and the impact on the oxidative stress response, cell cycle regulation and apoptosis were further analysed on the functional level. Cytotoxicity of CuO NP was more pronounced when compared to CuO MP and CuCl 2 in human bronchial epithelial BEAS-2B cells. Uptake studies revealed an intracellular copper overload in the soluble fractions of both cytoplasm and nucleus, reaching up to millimolar concentrations in case of CuO NP and considerably lower levels in case of CuO MP and CuCl 2 . Moreover, CuCl 2 caused copper accumulation in the nucleus only at cytotoxic concentrations. Gene expression analysis in BEAS-2B and A549 cells revealed a strong induction of uptake-related metallothionein genes, oxidative stress-sensitive and pro-inflammatory genes, anti-oxidative defense-associated genes as well as those coding for the cell cycle inhibitor p21 and the pro-apoptotic Noxa and DR5. While DNA damage inducible genes were activated, genes coding for distinct DNA repair factors were down-regulated. Modulation of gene expression was most pronounced in case of CuO NP as compared to CuO MP and CuCl 2 and more distinct in BEAS-2B cells. GSH depletion and activation of Nrf2 in HeLa S3 cells confirmed oxidative stress induction, mainly restricted to CuO NP. Also, cell cycle arrest and apoptosis induction were most distinct for CuO NP. The high cytotoxicity and marked impact on gene expression by CuO NP can be ascribed to the strong intracellular copper ion release, with subsequent

  17. An in-cell NMR study of monitoring stress-induced increase of cytosolic Ca{sup 2+} concentration in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Hembram, Dambarudhar Shiba Sankar; Haremaki, Takahiro; Hamatsu, Jumpei; Inoue, Jin; Kamoshida, Hajime; Ikeya, Teppei; Mishima, Masaki [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0373 (Japan); Mikawa, Tsutomu [Cellular and Molecular Biology Unit, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Hayashi, Nobuhiro [Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B-1, Nagatsuda-chou, Midori-ku, Yokohama, Kanagawa 226-8501 (Japan); Shirakawa, Masahiro [Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Ito, Yutaka, E-mail: ito-yutaka@tmu.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0373 (Japan)

    2013-09-06

    Highlights: •We performed time-resolved NMR observations of calbindin D{sub 9k} in HeLa cells. •Stress-induced increase of cytosolic Ca{sup 2+} concentration was observed by in-cell NMR. •Calbindin D{sub 9k} showed the state-transition from Mg{sup 2+}- to Ca{sup 2+}-bound state in cells. •We provide a useful tool for in situ monitoring of the healthiness of the cells. -- Abstract: Recent developments in in-cell NMR techniques have allowed us to study proteins in detail inside living eukaryotic cells. The lifetime of in-cell NMR samples is however much shorter than that in culture media, presumably because of various stresses as well as the nutrient depletion in the anaerobic environment within the NMR tube. It is well known that Ca{sup 2+}-bursts occur in HeLa cells under various stresses, hence the cytosolic Ca{sup 2+} concentration can be regarded as a good indicator of the healthiness of cells in NMR tubes. In this study, aiming at monitoring the states of proteins resulting from the change of cytosolic Ca{sup 2+} concentration during experiments, human calbindin D{sub 9k} (P47M + C80) was used as the model protein and cultured HeLa cells as host cells. Time-resolved measurements of 2D {sup 1}H–{sup 15}N SOFAST–HMQC experiments of calbindin D{sub 9k} (P47M + C80) in HeLa cells showed time-dependent changes in the cross-peak patterns in the spectra. Comparison with in vitro assignments revealed that calbindin D{sub 9k} (P47M + C80) is initially in the Mg{sup 2+}-bound state, and then gradually converted to the Ca{sup 2+}-bound state. This conversion process initiates after NMR sample preparation. These results showed, for the first time, that cells inside the NMR tube were stressed, presumably because of cell precipitation, the lack of oxygen and nutrients, etc., thereby releasing Ca{sup 2+} into cytosol during the measurements. The results demonstrated that in-cell NMR can monitor the state transitions of stimulated cells through the observation of

  18. Dietary supplementation with apple juice concentrate alleviates the compensatory increase in glutathione synthase transcription and activity that accompanies dietary- and genetically-induced oxidative stress.

    Science.gov (United States)

    Tchantchou, F; Graves, M; Ortiz, D; Rogers, E; Shea, T B

    2004-01-01

    Increased oxidative stress, which can arise from dietary, environmental and/or genetic sources, contributes to the decline in cognitive performance during normal aging and in neurodegenerative conditions such as Alzheimer's disease. Supplementation with fruits and vegetables that are high in antioxidant potential can compensate for dietary and/or genetic deficiencies that promote increased oxidative stress. We have recently demonstrated that apple juice concentrate (AJC) prevents the increase in oxidative damage to brain tissue and decline in cognitive performance observed when transgenic mice lacking apolipoprotein E (ApoE-/-) are maintained on a vitamin-deficient diet and challenged with excess iron (included in the diet as a pro-oxidant). However, the mechanism by which AJC provided neuroprotection was not conclusively determined. Herein, we demonstrate that supplementation with AJC also prevents the compensatory increases in glutathione synthase transcription and activity that otherwise accompany maintenance of ApoE-/- mice on this vitamin-free diet in the presence of iron. Inclusion of the equivalent composition and concentration of sugars of AJC did not prevent these increases. These findings provide further evidence that the antioxidant potential of AJC can compensate for dietary and genetic deficiencies that otherwise promote neurodegeneration.

  19. Inactivation by oxidation and recruitment into stress granules of hOGG1 but not APE1 in human cells exposed to sub-lethal concentrations of cadmium

    International Nuclear Information System (INIS)

    Bravard, Anne; Campalans, Anna; Vacher, Monique; Gouget, Barbara; Levalois, Celine; Chevillard, Sylvie; Radicella, J. Pablo

    2010-01-01

    The induction of mutations in mammalian cells exposed to cadmium has been associated with the oxidative stress triggered by the metal. There is increasing evidence that the mutagenic potential of Cd is not restricted to the induction of DNA lesions. Cd has been shown to inactivate several DNA repair enzymes. Here we show that exposure of human cells to sub-lethal concentrations of Cd leads to a time- and concentration-dependent decrease in hOGG1 activity, the major DNA glycosylase activity responsible for the initiation of the base excision repair (BER) of 8-oxoguanine, an abundant and mutagenic form of oxidized guanine. Although there is a slight effect on the level of hOGG1 transcripts, we show that the inhibition of the 8-oxoguanine DNA glycosylase activity is mainly associated with an oxidation of the hOGG1 protein and its disappearance from the soluble fraction of total cell extracts. Confocal microscopy analyses show that in cells exposed to Cd hOGG1-GFP is recruited to discrete structures in the cytoplasm. These structures were identified as stress granules. Removal of Cd from the medium allows the recovery of the DNA glycosylase activity and the presence of hOGG1 in a soluble form. In contrast to hOGG1, we show here that exposure to Cd does not affect the activity of the second enzyme of the pathway, the major AP endonuclease APE1.

  20. Due diligence

    International Nuclear Information System (INIS)

    Sanghera, G.S.

    1999-01-01

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  1. A study on fatigue crack growth behavior subjected to a single tensile overload: Part II. Transfer of stress concentration and its role in overload-induced transient crack growth

    International Nuclear Information System (INIS)

    Lee, S.Y.; Choo, H.; Liaw, P.K.; An, K.; Hubbard, C.R.

    2011-01-01

    The combined effects of overload-induced enlarged compressive residual stresses and crack tip blunting with secondary cracks are suggested to be responsible for the observed changes in the crack opening load and resultant post-overload transient crack growth behavior [Lee SY, Liaw PK, Choo H, Rogge RB, Acta Mater 2010;59:485-94]. In this article, in situ neutron diffraction experiments were performed to quantify the influence of the combined effects by investigating the internal-stress evolution at various locations away from the crack tip. In the overload-retardation period, stress concentration occurs in the crack blunting region (an overload point) until a maximum crack arrest load is reached. The stress concentration is then transferred from the blunting region to the propagating crack tip (following the overload), requiring a higher applied load, as the closed crack is gradually opened. The transfer phenomena of the stress concentration associated with a crack opening process account for the nonlinearity of strain response in the vicinity of the crack tip. The delaying action of stress concentration at the crack tip is understood in conjunction with the concept of a critical stress (i.e. the stress required to open the closed crack behind the crack tip). A linear relationship between Δε eff and ΔK eff provides experimental support for the hypothesis that ΔK eff can be considered as the fatigue crack tip driving force.

  2. Quasi-Static Transient Thermal Stresses in an Elliptical Plate due to Sectional Heat Supply on the Curved Surfaces over the Upper Face

    Directory of Open Access Journals (Sweden)

    Lalsingh Khalsa

    2018-01-01

    Full Text Available This paper is an attempt to determine quasi-static thermal stresses in a thin elliptical plate which is subjected to transient temperature on the top face with zero temperature on the lower face and the homogeneous boundary condition of the third kind on the fixed elliptical curved surface. The solution to conductivity equation is elucidated by employing a classical method. The solution of stress components is achieved by using Goodier’s and Airy’s potential function involving the Mathieu and modified functions and their derivatives. The obtained numerical results are accurate enough for practical purposes, better understanding of the underlying elliptic object, and better estimates of the thermal effect on the thermoelastic problem. The conclusions emphasize the importance of better understanding of the underlying elliptic structure, improved understanding of its relationship to circular object profile, and better estimates of the thermal effect on the thermoelastic problem.

  3. The effect of the method of application and concentration of asahi sl on the response of cucumber plants to chilling stress

    Directory of Open Access Journals (Sweden)

    Edward Borowski

    2012-12-01

    Full Text Available In pot experiments conducted on cucumber cv. Śremski F1, the effect was studied of short-term chilling stress on plants which had grown from seeds germinating in the solution of Asahi SL or treated with this biostimulator during the early growth period. The plants were grown in a phytotron at an air temperature of 27/22°C (day/night, using fluorescent light with FAR flux density of 220 μmol x m-2 x s-1 and with a photoperiod of 16/8. The biostimulator was applied using the following methods: a germination of seeds in 0.01% and 0.05% solution, b watering of plants twice with 0.01% or 0.05% solution, c spraying leaves with 0.3% or 0.5% solution. Plants sprayed with distilled water were the control. After 24 hours from foliar or root application of Asahi SL, one half of the plants from each experimental series was treated for a period of 3 days at a temperature of 12/6°C, with all the other growth conditions unchanged. The obtained results show that short-term chilling stress caused a significant increase in electrolyte leakage, free proline content and in the activity of ascorbate peroxidase in leaves, but a decrease in the content of chlorophyll, its maximum fluorescence (Fm and quantum yield (Fv/Fm, carotenoid content, stomatal conductance, transpiration, photosynthesis, leaf biomass and in the activity of catalase in leaves. Foliar or root application of Asahi SL in the pre-stress period decreased the values of the traits which increased as a result of chilling or increased those which decreased. Higher concentrations of the biostimulator solutions, applied using this method, were more effective. The application of the biostimulator during seed germination did not result in significant changes in the response of plants to chilling stress.

  4. Stress concentration during pellet cladding interaction: Comparison of closed-form solutions with 2D(r,θ) finite element simulations

    International Nuclear Information System (INIS)

    Sercombe, Jérôme; Masson, Renaud; Helfer, Thomas

    2013-01-01

    Highlights: • This paper presents closed-formed solutions concerning pellet cladding interaction. • First, the opening of a radial crack in a pellet fragment is estimated. • Second, the stresses in the cladding in front of the pellet crack are calculated. • The closed-formed solutions are found in good agreement with 2D FE simulations. • They are then used in the fuel code ALCYONE to model PCI during power ramps. -- Abstract: This paper presents two closed-form solutions that can be used to enrich the mechanical description of fuel pellets and cladding behavior in standard one-dimensional based fuel performance codes. The first one is concerned with the estimation of the opening of a radial crack in a pellet fragment induced by the radial thermal gradient in the pellet and limited by the pellet-clad contact pressure. The second one describes the stress distribution in a cladding bore in front of an opening pellet crack. A linear angular variation of the pellet-clad contact pressure and a constant prescribed radial displacement are considered. The closed-form solutions are checked by comparison to independent finite element models of the pellet fragment and of the cladding. Their ability to describe non-axisymmetric displacement and stress fields during loading histories representative of base irradiation and power ramps is then demonstrated by cross-comparison with the 2D pellet fragment-cladding model of the multi-dimensional fuel performance code ALCYONE. The calculated radial crack opening profiles at different times and the hoop stress concentration in the cladding at the top of the ramp are found in good agreement with ALCYONE

  5. Design and development of a radio-ecological domestic user friendly code for calculation of radiation doses and concentration due to airborn radionuclides release during the accidental and normal operation in nuclear installations

    Energy Technology Data Exchange (ETDEWEB)

    Shad, A. Haghighi; Allaf, M. Athari [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering; Masti, D. [Azad Univ., Boushehr (Iran, Islamic Republic of). Research and Developement in BNPP-1; Sepanloo, K. [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Reactor and Nuclear Safety School; Feghhi, S.A.H. [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering; Khodadadi, R. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Science and Research Branch

    2018-02-15

    A domestic user friendly dynamic radiological dose and model has been developed to estimate radiation doses and stochastic risks due to atmospheric and liquid discharges of radionuclides in the case of a nuclear reactor accident and normal operation. In addition to individual doses from different pathways for different age groups, collective doses and stochastic risks can be calculated by the developed domestic user friendly KIANA Advance Computational Computer Code and model. The current Code can be coupled to any long-range atmospheric dispersion/short term model which can calculate radionuclide concentrations in air and on the ground and in the water surfaces predetermined time intervals or measurement data.

  6. Design and development of a radio-ecological domestic user friendly code for calculation of radiation doses and concentration due to airborn radionuclides release during the accidental and normal operation in nuclear installations

    International Nuclear Information System (INIS)

    Shad, A. Haghighi; Allaf, M. Athari; Masti, D.; Sepanloo, K.; Feghhi, S.A.H.; Khodadadi, R.

    2018-01-01

    A domestic user friendly dynamic radiological dose and model has been developed to estimate radiation doses and stochastic risks due to atmospheric and liquid discharges of radionuclides in the case of a nuclear reactor accident and normal operation. In addition to individual doses from different pathways for different age groups, collective doses and stochastic risks can be calculated by the developed domestic user friendly KIANA Advance Computational Computer Code and model. The current Code can be coupled to any long-range atmospheric dispersion/short term model which can calculate radionuclide concentrations in air and on the ground and in the water surfaces predetermined time intervals or measurement data.

  7. Investigation of stress in a circular tunnel due to overburden and thermal loading of horizontally placed 21 PWR multi purpose canisters

    International Nuclear Information System (INIS)

    Kandalaft-Ladkany, N.; Wyman, R.V.

    1994-01-01

    The drift of a High Level Nuclear Waste (HLNW) Repository were subjected to 2-D thermal loading resulting from the horizontal emplacement of 125 Ton Multi-Purpose Canisters (MPC). Ten 2-D temperature profiles, resulting from 57 Kw/acre and 114 Kw/acre thermal loading conditions, were used in a finite element analysis of the drift; in which a quadrant of the drift and surrounding rock ±100m above and below the drift were modeled. Our analysis shows that the 114 Kw/acre thermal loading results in compressive stresses around the drift, 60 years after emplacement, that exceed the unconfined compressive strength of the TSW tuff analyzed. Stresses resulting from a 57 Kw/acre thermal loading are within the acceptable limit in tunnel rock. A parametric analysis of the invert backfill material showed that Young's modulus for the invert backfill should closely match that of the surrounding unconfined rock in the tunnel in order to prevent an unacceptable stress rise in both rock and backfill

  8. Occupational Stress

    OpenAIRE

    Löblová, Klára

    2011-01-01

    The thesis deals with load, stress and related questions of the working life. Work-related stress brings numerous difficulties not only to affected individuals, but as a result also to organizations. The thesis follows symptoms, impacts, somatic and mental aspects of stress, its types and also types of stressors, which cause this problem. It is concentrated on workload as a specific area of work-related stress, individual resistance to the load, factors of workload and work-related stress and...

  9. Rheology of concentrated biomass

    Science.gov (United States)

    J.R. Samaniuk; J. Wang; T.W. Root; C.T. Scott; D.J. Klingenberg

    2011-01-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained...

  10. Posttraumatic stress disorder in a World War II concentration camp survivor caused by the attack of two German shepherd dogs: case report and review of the literature.

    Science.gov (United States)

    Jovanović, Aleksandar A; Ivković, Maja; Gašić, Miroslava Jašović

    2011-05-20

    A 79-year-old woman suffered from acute posttraumatic stress disorder (PTSD) and a loco typico, non-displaced fracture of her right distal radius due to an incident involving the assault of two unleashed owned dogs, which suddenly ran into her and aggressively jumped on her chest and knocked her down to the ground. Recovery for her damage claim concerning pain and disability due to her right forearm fracture caused by the incident, was not the issue in the litigation concerned. However, the issue of delayed impact of her previous Holocaust experience placed a significant challenge on M.N., as a plaintiff, in establishing a causal link between the posttraumatic stress disorder concerned and the alleged harmful action of the defendants, the owners of the two dogs. The case reported here proved interesting and instructive not only in the sense of addressing main issues relevant to litigation for psychological damage related to reactivated PTSD and delayed PTSD, but also in the sense of pointing at the clinical relevance of dog assaults on humans which, even without dog bite injuries, may result in a severe traumatization and eventual civil lawsuit. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Effect of Salinity Stress on Concentrations of Nutrition Elements in Almond (Prunus Dulcis 'Shokofeh', 'Sahand' Cultivars and '13-40' Genotype Budded on GF677 Rootstock

    Directory of Open Access Journals (Sweden)

    A. Momenpour

    2016-02-01

    Full Text Available Introduction: Almond (Prunus amygdalus B. is one of the most important crops consumed as a dry fruit and it is mainly adaptable to arid and semi-arid regions mostly suffering from salinity stress (8. Soils with dry humidity regime are dominant in Iran and in the world at large and mostly include regions with more evaporation than precipitation. This in turn leads to increased salinity of the soil (9 and 10. Based on available reports, roughly 12.5% of land areas in Iran are saline, which overwhelmingly contain sodium, while more than 800 million hectares of land area on the earth (6% of overall global land area are affected by salinity (9 and 10. Therefore, compound of rootstock and scion may be used as one of the influence factors in sensitivity or tolerance to salinity of planted fruit trees including almonds (8 and 11. In recent years, for various reasons including the uniformity of trees, instead of sexual rootstock, vegetative rootstock is used. Rootstock GF677 an inter-specific hybrid (Almond Peach is propagated asexually as clone (8. It has been reported that rootstock GF677 is tolerant to salinity while rootstock nemagard (P. persica X P. davidiana is sensitive to salinity (16. It has been reported that rootstock GF677 tolerated salinity (5.5 ds/m, (19 or 5.2 ds/m (17 and 14.However, as plant species and different cultivars within the same plant species vary considerably in their tolerance to salinity (10, properly selecting plants and/or cultivars that can be grown well under adverse conditions, created in the root zone by salinization, is the most efficient and environmentally friendly agricultural practice for a more permanent solution of the problem of salinity (10. Despite the presence of information on the effect of salinity on concentration of nutrition elements of almond cultivars leaves and roots, tolerantscion/rootstock combinationshave not been introduced for this plant. Therefore, the aim of the present study is to

  12. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis.

    Science.gov (United States)

    Novais, Paolla Gabrielle Nascimento; Batista, Karla de Melo; Grazziano, Eliane da Silva; Amorim, Maria Helena Costa

    2016-09-01

    to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group). The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (pencontros quinzenais em um período de oito semanas. O grupo experimental foi orientado a realizar diariamente o Relaxamento Muscular Progressivo. Após oito semanas de intervenção avaliou-se novamente os níveis de estresse. Para análise dos dados foi utilizado o pacote Estatístico para Ciências Sociais-versão 19.0. a aplicação do Teste t demonstrou uma diminuição significante dos escores da Escala de Stress Percebido no grupo experimental (p<0,001), evidenciando diminuição nos níveis de estresse após a prática do relaxamento. a intervenção Relaxamento Muscular Progressivo contribui para redução dos níveis de estresse em pessoas com Esclerose Múltipla, podendo ser incluída como prática na assistência de enfermagem prestada a esses pacientes. NCT 02673827. evaluar el efecto del Relajamiento Muscular Progresivo, como intervención de Enfermería en los niveles de estrés en personas con Esclerosis

  13. The physiological and biochemical responses of a medicinal plant (Salvia miltiorrhiza L. to stress caused by various concentrations of NaCl.

    Directory of Open Access Journals (Sweden)

    Zhao Gengmao

    Full Text Available Salvia miltiorrhiza, which is commonly known as Danshen, is a traditional Chinese herbal medicine. To illustrate its physiological and biochemical responses to salt stress and to evaluate the feasibility of cultivating this plant in saline coastal soils, a factorial experiment under hydroponic conditions was arranged on the basis of a completely randomised design with three replications. Five salinity treatments (0, 25, 50, 75 and 100 mM NaCl were employed in this experiment. The results showed that salinity treatments of <100 mM NaCl did not affect the growth of Salvia miltiorrhiza in a morphological sense, but significantly inhibit the accumulation of dry matter. Salinity treatments significantly decreased the Chl-b content but caused a negligible change in the Chl-a content, leading to a conspicuous overall decrease in the T-Chl content. The Na(+ content significantly increased with increasing hydroponic salinity but the K(+ and Ca(2+ contents were reversed, indicating that a high level of external Na(+ resulted in a decrease in both K(+ and Ca(2+ concentrations in the organs of Salvia miltiorrhiza. Salt stress significantly decreased the superoxide dismutase (SOD activity of Salvia miltiorrhiza leaves in comparison with that of the control. On the contrary, the catalase (CAT activity in the leaves markedly increased with the increasing salinity of the hydroponic solution. Moreover, the soluble sugar and protein contents in Salvia miltiorrhiza leaves dramatically increased with the increasing salinity of the hydroponic solution. These results suggested that antioxidant enzymes and osmolytes are partially involved in the adaptive response to salt stress in Salvia miltiorrhiza, thereby maintaining better plant growth under saline conditions.

  14. [Music as adjuvant therapy for coronary heart disease. Therapeutic music lowers anxiety, stress and beta-endorphin concentrations in patients from a coronary sport group].

    Science.gov (United States)

    Vollert, J O; Störk, T; Rose, M; Möckel, M

    2003-12-19

    In a study with coronary patients it was estimated that music is able to lower stress and fear and contributing to relaxation in spite of physical exercise. 15 patients (13 male, two female, mean age 62,2 +/- 7,6 years) of a coronary sport unit were listening to an especially composed relaxation music while training their common heart-frequency adapted exercises. Before the exercises and after listening to music blood pressures were measured and blood was collected for determination of beta-endorphin. Simultaneous to blood collection the participants had to perform two psychometric test: the perceived stress experience questionnaire (PSQ) of Levenstein to measure the graduation of subjective perceived stress and the state-anxiety inquiry (STAI) of Spielberger as an indicator of coping. To practice the trial ("test trial"), the whole protocol was performed one week prior to the mean trial, but without listening to music and without blood collections and blood pressure measurements. In the test trial without music there were no significant changes in PSQ-data. In the mean trial, under the influence of music, values in the section "worries" decreased as a sign of lower worries (26.6 versus 27.6; p = 0.039). STAI-values were significantly lower as a sign of reduced fear after listening to music (31 versus 34; p = 0.045). beta-endorphin concentration (10.91 microg/l versus 15.96 microg/l, p = 0.044) and systolic blood pressure (130 mmHg versus 140 mmHg; p = 0.007) decreased significantly after listening to music. Regarding worries and fear, patients seemed to benefit by the intervention of music. beta-endorphin was lowered significantly after music despite physical activity.

  15. Recovery of normal testicular temperature after scrotal heat stress in rams assessed by infrared thermography and its effects on seminal characteristics and testosterone blood serum concentration.

    Science.gov (United States)

    Alves, Maíra Bianchi Rodrigues; Andrade, André Furugen Cesar de; Arruda, Rubens Paes de; Batissaco, Leonardo; Florez-Rodriguez, Shirley Andrea; Oliveira, Bruna Marcele Martins de; Torres, Mariana Andrade; Lançoni, Renata; Ravagnani, Gisele Mouro; Prado Filho, Roberto Romano do; Vellone, Vinícius Silva; Losano, João Diego de Agostini; Franci, Celso Rodrigues; Nichi, Marcílio; Celeghini, Eneiva Carla Carvalho

    2016-08-01

    Reestablishment of testicular normal temperature after testicular heat stress is unknown and its effect varies widely. The aim of this study was to investigate the impact of scrotal insulation (IN) on testicular temperature and its relation to semen quality and testosterone blood serum concentration. For this, 33 rams were used; 17 submitted to IN for 72 hours (using bags involving the testes) and 16 not submitted to IN (control group). The experiment was performed between August and December 2013 in Pirassununga, Brazil (21°56″13″ South/47°28'24″ West). Seminal characteristics, testosterone blood serum concentration, rectal temperature (RT), respiratory frequency, scrotal superficies mean temperature (SSMT), and eye area mean temperature (EAMT) were analyzed 7 days before IN and 21, 35, 49, 63, and 90 days afterward. Scrotal superficies mean temperature and EAMT were measured by thermography camera FLIR T620. Testosterone was evaluated by radioimmunoassay. Analysis of variance was used to determine the main effects of treatment, time, and treatment-by-time interaction using PROC MIXED of SAS software adding command REPEAT. Pearson correlation test was used to verify correlation between SSMT, EAMT, RT, and respiratory frequency. Significant difference was considered when P ≤ 0.05. At the end of IN, SSMT was higher (P blood serum concentration was lesser in insulated rams (P = 0.03). Thus, the difference of 1.12 °C between RT and testicular temperature impacts semen quality and testosterone blood serum concentration. Moreover, this study shows that rams can recover testes temperature efficiently toward IN and that infrared thermography is an efficient tool to identify differences on SSMT. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Non-toxic engineered carbon nanodiamond concentrations induce oxidative/nitrosative stress, imbalance of energy metabolism, and mitochondrial dysfunction in microglial and alveolar basal epithelial cells.

    Science.gov (United States)

    Fresta, Claudia G; Chakraborty, Aishik; Wijesinghe, Manjula B; Amorini, Angela M; Lazzarino, Giacomo; Lazzarino, Giuseppe; Tavazzi, Barbara; Lunte, Susan M; Caraci, Filippo; Dhar, Prajnaparamita; Caruso, Giuseppe

    2018-02-14

    Engineered nanoparticles are finding a wide spectrum of biomedical applications, including drug delivery and capacity to trigger cytotoxic phenomena, potentially useful against tumor cells. The full understanding of their biosafety and interactions with cell processes is mandatory. Using microglial (BV-2) and alveolar basal epithelial (A549) cells, in this study we determined the effects of engineered carbon nanodiamonds (ECNs) on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) production, as well as on energy metabolism. Particularly, we initially measured decrease in cell viability as a function of increasing ECNs doses, finding similar cytotoxic ECN effects in the two cell lines. Subsequently, using apparently non-cytotoxic ECN concentrations (2 µg/mL causing decrease in cell number < 5%) we determined NO and ROS production, and measured the concentrations of compounds related to energy metabolism, mitochondrial functions, oxido-reductive reactions, and antioxidant defences. We found that in both cell lines non-cytotoxic ECN concentrations increased NO and ROS production with sustained oxidative/nitrosative stress, and caused energy metabolism imbalance (decrease in high energy phosphates and nicotinic coenzymes) and mitochondrial malfunctioning (decrease in ATP/ADP ratio).These results underline the importance to deeply investigate the molecular and biochemical changes occurring upon the interaction of ECNs (and nanoparticles in general) with living cells, even at apparently non-toxic concentration. Since the use of ECNs in biomedical field is attracting increasing attention the complete evaluation of their biosafety, toxicity and/or possible side effects both in vitro and in vivo is mandatory before these highly promising tools might find the correct application.

  17. Discovery and Function of a General Core Hormetic Stress Response in E. coli Induced by Sublethal Concentrations of Antibiotics.

    Science.gov (United States)

    Mathieu, Aurélie; Fleurier, Sébastien; Frénoy, Antoine; Dairou, Julien; Bredeche, Marie-Florence; Sanchez-Vizuete, Pilar; Song, Xiaohu; Matic, Ivan

    2016-09-27

    A better understanding of the impact of antibiotics on bacteria is required to increase the efficiency of antibiotic treatments and to slow the emergence of resistance. Using Escherichia coli, we examined how bacteria exposed to sublethal concentrations of ampicillin adjust gene expression patterns and metabolism to simultaneously deal with the antibiotic-induced damage and maintain rapid growth. We found that the treated cells increased energy production, as well as translation and macromolecular repair and protection. These responses are adaptive, because they confer increased survival not only to lethal ampicillin treatment but also to non-antibiotic lethal stresses. This robustness is modulated by nutrient availability. Because different antibiotics and other stressors induce the same set of responses, we propose that it constitutes a general core hormetic stress response. It is plausible that this response plays an important role in the robustness of bacteria exposed to antibiotic treatments and constant environmental fluctuations in natural environments. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  18. Protective Effects of Maillard Reaction Products of Whey Protein Concentrate against Oxidative Stress through an Nrf2-Dependent Pathway in HepG2 Cells.

    Science.gov (United States)

    Pyo, Min Cheol; Yang, Sung-Yong; Chun, Su-Hyun; Oh, Nam Su; Lee, Kwang-Won

    2016-09-01

    Whey protein concentrate (WPC), which contains α-lactalbumin and β-lactoglobulin, is utilized widely in the food industry. The Maillard reaction is a complex reaction that produces Maillard reaction products (MRPs), which are associated with the formation of antioxidant compounds. In this study, the hepatoprotection activity of MRPs of WPC against oxidative stress through the nuclear factor-E2-related factor 2 (Nrf2)-dependent antioxidant pathway in HepG2 cells was examined. Glucose-whey protein concentrate conjugate (Glc-WPC) was obtained from Maillard reaction between WPC and glucose. The fluorescence intensity of Glc-WPC increased after 7 d compared to native WPC, and resulted in loss of 48% of the free amino groups of WPC. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of Glc-WPC showed the presence of a high-molecular-weight portion. Treatment of HepG2 cells with Glc-WPC increased cell viability in the presence of oxidative stress, inhibited the generation of intracellular reactive oxygen species by tert-butyl hydroperoxide (t-BHP), and increased the glutathione level. Nrf2 translocation and Nrf2, reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H)-quinone oxidoreductase 1 (NOQ1), heme oxygenase-1 (HO-1), glutamate-L-cysteine ligase (GCL)M and GCLC mRNA levels were increased by Glc-WPC. Also, Glc-WPC increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK). The results of this study demonstrate that Glc-WPC activates the Nrf2-dependent pathway through the phosphorylation of ERK1/2 and JNK in HepG2 cells, and induces production of antioxidant enzymes and phase II enzymes.

  19. Liver Melanomacrophages and Gluthation S-Transferase Activity in Leptodactylus chaquensis (ANURA, LEPTODACTYLIDAE as Biomarkers of Oxidative Stress Due to Chlorpyrifos Exposition

    Directory of Open Access Journals (Sweden)

    Ivan Huespe

    2017-05-01

    Full Text Available We quantified and compared the hepatic melanomacrophage (MM and glutathione S-transferase (GST enzyme activity (two oxidative stress biomarkers in the liver of Leptodatylus chaquensis adults (Anura, Leptodactylidae collected in a rice field (CA in San Javier department, Santa Fe (Argentina, seven days after the application of chlorpyrifos and in a reference site (SR. The histological analysis revealed a significant amount (p = 0.028 and area occupied by MM (p = 0.017 in livers of CA compared to SR. Furthermore, a significant inhibition of GST activity was recorded in the CA frogs compared to the SR (p = 0.030. The histopathological and enzymatic effects provide evidences of ecotoxicological risk for anurans in rice field with CPF application.

  20. Early life stress impairs social recognition due to a blunted response of vasopressin release within the septum of adult male rats.

    Science.gov (United States)

    Lukas, Michael; Bredewold, Remco; Landgraf, Rainer; Neumann, Inga D; Veenema, Alexa H

    2011-07-01

    Early life stress poses a risk for the development of psychopathologies characterized by disturbed emotional, social, and cognitive performance. We used maternal separation (MS, 3h daily, postnatal days 1-14) to test whether early life stress impairs social recognition performance in juvenile (5-week-old) and adult (16-week-old) male Wistar rats. Social recognition was tested in the social discrimination test and defined by increased investigation by the experimental rat towards a novel rat compared with a previously encountered rat. Juvenile control and MS rats demonstrated successful social recognition at inter-exposure intervals of 30 and 60 min. However, unlike adult control rats, adult MS rats failed to discriminate between a previously encountered and a novel rat after 60 min. The social recognition impairment of adult MS rats was accompanied by a lack of a rise in arginine vasopressin (AVP) release within the lateral septum seen during social memory acquisition in adult control rats. This blunted response of septal AVP release was social stimulus-specific because forced swimming induced a rise in septal AVP release in both control and MS rats. Retrodialysis of AVP (1 μg/ml, 3.3 μl/min, 30 min) into the lateral septum during social memory acquisition restored social recognition in adult MS rats at the 60-min interval. These studies demonstrate that MS impairs social recognition performance in adult rats, which is likely caused by blunted septal AVP activation. Impaired social recognition may be linked to MS-induced changes in other social behaviors like aggression as shown previously. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Severe maternal stress exposure due to bereavement before, during and after pregnancy and risk of overweight and obesity in young adult men: a Danish National Cohort Study.

    Directory of Open Access Journals (Sweden)

    Lena Hohwü

    Full Text Available BACKGROUND: Perinatal stress may programme overweight and obesity. We examined whether maternal pre- and post-natal bereavement was associated with overweight and obesity in young men. METHODS: A cohort study was conducted including 119,908 men born from 1976 to 1993 and examined for military service between 2006 and 2011. Among them, 4,813 conscripts were born to mothers bereaved by death of a close relative from 12 months preconception to birth of the child (exposed group. Median body mass index (BMI and prevalence of overweight and obesity were estimated. Odds ratio of overweight (BMI≥25 kg/m2 and obesity (BMI≥30 kg/m2 were estimated by logistic regression analysis adjusted for maternal educational level. RESULTS: Median BMI was similar in the exposed and the unexposed group but the prevalence of overweight (33.3% versus 30.4%, p = 0.02 and obesity (9.8% versus 8.5%, p = 0.06 was higher in the exposed group. Conscripts exposed 6 to 0 months before conception and during pregnancy had a higher risk of overweight (odds ratio 1.15, 95% confidence interval (CI: 1.03; 1.27 and odds ratio 1.13, 95% CI: 1.03; 1.25, respectively. Conscripts born to mothers who experienced death of the child's biological father before child birth had a two-fold risk of obesity (odds ratio 2.00, 95% CI: 0.93; 4.31. There was no elevated risk in those who experienced maternal bereavement postnatally. CONCLUSION: Maternal bereavement during the prenatal period was associated with increased risk of overweight or obesity in a group of young male conscripts, and this may possibly be reflected to severe stress exposure early in life. However, not all associations were clear, and further studies are warranted.

  2. Severe maternal stress exposure due to bereavement before, during and after pregnancy and risk of overweight and obesity in young adult men: a Danish National Cohort Study.

    Science.gov (United States)

    Hohwü, Lena; Li, Jiong; Olsen, Jørn; Sørensen, Thorkild I A; Obel, Carsten

    2014-01-01

    Perinatal stress may programme overweight and obesity. We examined whether maternal pre- and post-natal bereavement was associated with overweight and obesity in young men. A cohort study was conducted including 119,908 men born from 1976 to 1993 and examined for military service between 2006 and 2011. Among them, 4,813 conscripts were born to mothers bereaved by death of a close relative from 12 months preconception to birth of the child (exposed group). Median body mass index (BMI) and prevalence of overweight and obesity were estimated. Odds ratio of overweight (BMI≥25 kg/m2) and obesity (BMI≥30 kg/m2) were estimated by logistic regression analysis adjusted for maternal educational level. Median BMI was similar in the exposed and the unexposed group but the prevalence of overweight (33.3% versus 30.4%, p = 0.02) and obesity (9.8% versus 8.5%, p = 0.06) was higher in the exposed group. Conscripts exposed 6 to 0 months before conception and during pregnancy had a higher risk of overweight (odds ratio 1.15, 95% confidence interval (CI): 1.03; 1.27 and odds ratio 1.13, 95% CI: 1.03; 1.25, respectively). Conscripts born to mothers who experienced death of the child's biological father before child birth had a two-fold risk of obesity (odds ratio 2.00, 95% CI: 0.93; 4.31). There was no elevated risk in those who experienced maternal bereavement postnatally. Maternal bereavement during the prenatal period was associated with increased risk of overweight or obesity in a group of young male conscripts, and this may possibly be reflected to severe stress exposure early in life. However, not all associations were clear, and further studies are warranted.

  3. Prevalence of Post-Traumatic Stress Disorder Due to Community Violence Among University Students in the World's Most Dangerous Megacity: A Cross-Sectional Study From Pakistan.

    Science.gov (United States)

    Khan, Abdul Ahad; Haider, Ghani; Sheikh, Maryam Rahim; Ali, Ambreen Fatima; Khalid, Zain; Tahir, Muhammad Munaim; Malik, Tayyaba Maqbool; Salick, Muhammad Musa; Lakhani, Laila Saleem; Yousuf, Fatimah Sireen; Khan, Muhammad Babar; Saleem, Sarah

    2016-08-01

    Community violence among the youth can lead to a number of adverse psychiatric outcomes including post-traumatic stress disorder (PTSD). However, little research has been conducted in non-Western countries to assess this problem. This study aims to fill the void by assessing the lifetime exposure to traumatic events and burden of probable PTSD among university students in Karachi, Pakistan. A cross-sectional study was conducted at four private institutions in Karachi. Self-administered questionnaires were filled out by 320 students. Lifetime exposure and symptoms of PTSD were assessed using modified Composite International Diagnostic Interview (CIDI) and Post-Traumatic Stress Disorder Checklist-Civilian Version (PCL-C) questionnaires, respectively. A PCL-C score of 44 or above was used as cutoff for probable PTSD. Pearson chi-square test was used to assess the association between PTSD and different variables at a level of significance of 5%. Ninety-three percent of the respondents reported having lifetime exposure to at least one traumatic event with sudden unexpected death of a loved one (n = 187) and assaultive violence (n = 169) being the commonest reported traumatic events. Positive association for PTSD was seen with enduring physical attacks and motor vehicle accidents. Over a quarter of the students screened positive for probable PTSD, among them almost one third were male and 17% were female. Our results indicate a high exposure to violent events and elevated rates of lifetime PTSD among urban youth. Reduction in violence and better access to mental health facilities is warranted to decrease the health burden of PTSD in Pakistan. © The Author(s) 2015.

  4. Disfunção ventricular esquerda transitória por cardiomiopatia induzida por estresse Transient left ventricular dysfunction due to stress-induced cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Simões

    2007-10-01

    Full Text Available Apresenta-se o caso de uma paciente de 71 anos que preencheu os critérios diagnósticos para cardiomiopatia induzida por estresse que foi desencadeada por intenso estresse emocional após atropelamento por bicicleta. O quadro clínico mimetizou o infarto agudo do miocárdio, manifestando-se com dor precordial, supradesnivelamento do segmento ST, seguido por ondas T profundas e prolongamento do intervalo QT, elevação discreta de enzimas cardíacas e cursando com disfunção sistólica apical do ventrículo esquerdo e hipercinesia das porções basais (conferindo o aspecto de "abaloamento apical", mas na ausência de obstrução coronariana subepicárdica. A função ventricular normalizou-se após a segunda semana de evolução.The case presented here is of a 71-yr-old female patient who met the diagnostic criteria for stress-induced cardiomyopathy, which was triggered by intense emotional stress after being hit by a bicycle. The clinical picture mimicked that of an acute myocardial infarction, manifesting as precordial pain, ST-segment depression followed by deep negative T waves and prolonging of the QT interval, slight increase in cardiac enzymes and coursing with transient apical ballooning of the left ventricle and hyperkinesis of the basal walls (conferring the aspect of "apical ballooning", although in the absence of subepicardial coronary obstruction. Ventricular function normalized after the second week of clinical evolution.

  5. Damage to photosystem II due to heat stress without light-driven electron flow: involvement of enhanced introduction of reducing power into thylakoid membranes.

    Science.gov (United States)

    Marutani, Yoko; Yamauchi, Yasuo; Kimura, Yukihiro; Mizutani, Masaharu; Sugimoto, Yukihiro

    2012-08-01

    Under a moderately heat-stressed condition, the photosystems of higher plants are damaged in the dark more easily than they are in the presence of light. To obtain a better understanding of this heat-derived damage mechanism that occurs in the dark, we focused on the involvement of the light-independent electron flow that occurs at 40 °C during the damage. In various plant species, the maximal photochemical quantum yield of photosystem (PS) II (Fv/Fm) decreased as a result of heat treatment in the dark. In the case of wheat, the most sensitive plant species tested, both Fv/Fm and oxygen evolution rapidly decreased by heat treatment at 40 °C for 30 min in the dark. In the damage, specific degradation of D1 protein was involved, as shown by immunochemical analysis of major proteins in the photosystem. Because light canceled the damage to PSII, the light-driven electron flow may play a protective role against PSII damage without light. Light-independent incorporation of reducing power from stroma was enhanced at 40 °C but not below 35 °C. Arabidopsis mutants that have a deficit of enzymes which mediate the incorporation of stromal reducing power into thylakoid membranes were tolerant against heat treatment at 40 °C in the dark, suggesting that the reduction of the plastoquinone pool may be involved in the damage. In conclusion, the enhanced introduction of reducing power from stroma into thylakoid membranes that occurs around 40 °C causes over-reduction of plastoquinone, resulting in the damage to D1 protein under heat stress without linear electron flow.

  6. Modeling of the Nano- and Picoseismicity Rate Changes Resulting from Static Stress Triggering due to Small (MW2.2) Event Recorded at Mponeng Deep Gold Mine, South Africa

    Science.gov (United States)

    Kozlowska, M.; Orlecka-Sikora, B.; Kwiatek, G.; Boettcher, M. S.; Dresen, G. H.

    2014-12-01

    Static stress changes following large earthquakes are known to affect the rate and spatio-temporal distribution of the aftershocks. Here we utilize a unique dataset of M ≥ -3.4 earthquakes following a MW 2.2 earthquake in Mponeng gold mine, South Africa, to investigate this process for nano- and pico- scale seismicity at centimeter length scales in shallow, mining conditions. The aftershock sequence was recorded during a quiet interval in the mine and thus enabled us to perform the analysis using Dietrich's (1994) rate and state dependent friction law. The formulation for earthquake productivity requires estimation of Coulomb stress changes due to the mainshock, the reference seismicity rate, frictional resistance parameter, and the duration of aftershock relaxation time. We divided the area into six depth intervals and for each we estimated the parameters and modeled the spatio-temporal patterns of seismicity rates after the stress perturbation. Comparing the modeled patterns of seismicity with the observed distribution we found that while the spatial patterns match well, the rate of modeled aftershocks is lower than the observed rate. To test our model, we used four metrics of the goodness-of-fit evaluation. Testing procedure allowed rejecting the null hypothesis of no significant difference between seismicity rates only for one depth interval containing the mainshock, for the other, no significant differences have been found. Results show that mining-induced earthquakes may be followed by a stress relaxation expressed through aftershocks located on the rupture plane and in regions of positive Coulomb stress change. Furthermore, we demonstrate that the main features of the temporal and spatial distribution of very small, mining-induced earthquakes at shallow depths can be successfully determined using rate- and state-based stress modeling.

  7. Uncovering the local inelastic interactions during manufacture of ductile cast iron: How the substructure of the graphite particles can induce residual stress concentrations in the matrix

    DEFF Research Database (Denmark)

    Andriollo, Tito; Hellström, Kristina; Sonne, Mads Rostgaard

    2018-01-01

    Recent X-ray diffraction (XRD) measurements have revealed that plastic deformation and a residual elastic strain field can be present around the graphite particles in ductile cast iron after manufacturing, probably due to some local mismatch in thermal contraction. However, as only one component...... of the elastic strain tensor could be obtained from the XRD data, the shape and magnitude of the associated residual stress field have remained unknown. To compensate for this and to provide theoretical insight into this unexplored topic, a combined experimental-numerical approach is presented in this paper...... the graphite particles and the matrix during manufacturing of the industrial part considered in the XRD study. The model indicates that, besides the vis- coplastic deformation of the matrix, the effect of the inelastic deformation of the graphite has to be considered to explain the magnitude of the XRD strain...

  8. Initiation process of the Mw 6.2 central Tottori, Japan, earthquake on October 21, 2016: Stress transfer due to its largest foreshock of Mw 4.1

    Science.gov (United States)

    Noda, S.; Ellsworth, W. L.

    2017-12-01

    On October 21, 2016, a strike-slip earthquake with Mw 6.2 occurred in the central Tottori prefecture, Japan. It was preceded by a foreshock sequence that began with a Mw 4.1 event, the largest earthquake for the sequence, and lasted about two hours. According to the JMA catalog, the largest foreshock had a similar focal mechanism as the mainshock and was located in the immediate vicinity of the mainshock hypocenter. The goal of this study is to understand the relationship between the foreshock and the initial rupture of the mainshock. We first determine the relative hypocenter distance between the foreshock and mainshock using the P-wave onsets on Hi-net station records. The initiation points of the two events are likely about 100 m apart according to the current results, but could be closer. Within the location uncertainty, they might either be coplanar or on subparallel planes. Next, we obtain the slip-history models from a kinematic inversion method using empirical Green's functions derived from other foreshocks with M 2.2 - 2.4. The Mw 4.1 foreshock and Mw 6.2 mainshock started in a similar way until approximately 0.2 s after their onsets. For the foreshock, the rapid growth stage completed by 0.2 s even though the rupture propagation continued for 0.4 - 0.5 s longer (note that 0.2 s is significantly shorter than the typical source duration of a Mw 4.1 earthquake). On the other hand, the mainshock rupture continued to grow rapidly after 0.2 s. The comparison between the relative hypocenter locations and the slip models shows that the mainshock nucleated within the area strongly effected by both static and dynamic stress changes created by the foreshock. We also find that the mainshock initially propagated away from the foreshock hypocenter. We consider that the stress transfer process is a key to understand the mainshock nucleation as well as its rupture growth process.

  9. Supplementation with nanomolar concentrations of verbascoside during in vitro maturation improves embryo development by protecting the oocyte against oxidative stress: a large animal model study.

    Science.gov (United States)

    Martino, Nicola Antonio; Ariu, Federica; Bebbere, Daniela; Uranio, Manuel Filioli; Chirico, Adriana; Marzano, Giuseppina; Sardanelli, Anna Maria; Cardinali, Angela; Minervini, Fiorenza; Bogliolo, Luisa; Dell'Aquila, Maria Elena

    2016-10-01

    The effects of verbascoside (VB), added at nanomolar concentrations during in vitro maturation (IVM) of juvenile sheep oocytes, on in vitro embryo development and its mechanisms of action at the oocyte level were analyzed. Developmental rates, after IVM in the presence/absence of VB (1nM for 24h; 1nM for 2h; 10nM for 2h), were evaluated. The bioenergetic/oxidative status of oocytes matured after IVM in the presence/absence of 1nM VB for 24h was assessed by confocal analysis of mitochondria and reactive oxygen species (ROS), lipid peroxidation (LPO) assay, and quantitative PCR of bioenergy/redox-related genes. The addition of 1nM VB during 24h IVM significantly increased blastocyst formation and quality. Verbascoside reduced oocyte ROS and LPO and increased mitochondria/ROS colocalization while keeping mitochondria activity and gene expression unchanged. In conclusion, supplementation with nanomolar concentrations of VB during IVM, in the juvenile sheep model, promotes embryo development by protecting the oocyte against oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Severe Maternal Stress Exposure Due to Bereavement before, during and after Pregnancy and Risk of Overweight and Obesity in Young Adult Men

    DEFF Research Database (Denmark)

    Hohwü, Lena; Li, Jiong; Olsen, Jørn

    2014-01-01

    BACKGROUND: Perinatal stress may programme overweight and obesity. We examined whether maternal pre- and post-natal bereavement was associated with overweight and obesity in young men. METHODS: A cohort study was conducted including 119,908 men born from 1976 to 1993 and examined for military...... service between 2006 and 2011. Among them, 4,813 conscripts were born to mothers bereaved by death of a close relative from 12 months preconception to birth of the child (exposed group). Median body mass index (BMI) and prevalence of overweight and obesity were estimated. Odds ratio of overweight (BMI≥25...... kg/m2) and obesity (BMI≥30 kg/m2) were estimated by logistic regression analysis adjusted for maternal educational level. RESULTS: Median BMI was similar in the exposed and the unexposed group but the prevalence of overweight (33.3% versus 30.4%, p = 0.02) and obesity (9.8% versus 8.5%, p = 0...

  11. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency

    International Nuclear Information System (INIS)

    Ribeiro, Mariana P.C.; Silva, Filomena S.G.; Santos, Armanda E.; Santos, Maria S.; Custódio, José B.A.

    2013-01-01

    Endoxifen (EDX) is a key active metabolite of tamoxifen (TAM) with higher affinity and specificity to estrogen receptors that also inhibits aromatase activity. It is safe and well tolerated by healthy humans, but its use requires toxicological characterization. In this study, the effects of EDX on mitochondria, the primary targets for xenobiotic-induced toxicity, were monitored to clarify its potential side effects. EDX up to 30 nmol/mg protein did not affect the mitochondrial oxidative phosphorylation. At 50 nmol EDX/mg protein, EDX decreased the ADP phosphorylation rate and a partial collapse of mitochondrial membrane potential (Δψ), that parallels a state 4 stimulation, was observed. As the stimulation of state 4 was not inhibited by oligomycin and 50 nmol EDX/mg protein caused a slight decrease in the light scattering of mitochondria, these data suggest that EDX promotes membrane permeabilization to protons, whereas TAM at the same concentration induced mitochondrial membrane disruption. Moreover, EDX at 10 nmol/mg protein prevented and reversed the Ca 2+ -induced depolarization of ΔΨ and the release of mitochondrial Ca 2+ , similarly to cyclosporine A, indicating that EDX did not affect Ca 2+ uptake, but directly interfered with the proteins of the mitochondrial permeability transition (MPT) megacomplex, inhibiting MPT induction. At this concentration, EDX exhibited antioxidant activity that may account for the protective effect against MPT pore opening. In conclusion, EDX within the range of concentrations reached in tissues did not significantly damage the bioenergetic functions of mitochondria, contrarily to the prodrug TAM, and prevented the MPT pore opening and the oxidative stress in mitochondria, supporting that EDX may be a less toxic drug for women with breast carcinoma. - Highlights: ► Mitochondria are important targets of Endoxifen. ► Endoxifen prevents mitochondrial permeability transition. ► Endoxifen prevents oxidative stress in

  12. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Mariana P.C.; Silva, Filomena S.G.; Santos, Armanda E. [Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra (Portugal); Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra (Portugal); Santos, Maria S. [Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra (Portugal); Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra (Portugal); Custódio, José B.A., E-mail: custodio@ci.uc.pt [Center for Neuroscience and Cell Biology, University of Coimbra,