WorldWideScience

Sample records for experimental stress analyses

  1. Numerical and Experimental Analyses of Residual Stresses in

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Hattel, Jesper; Lorentzen, Torben

    1999-01-01

    been done using the novel non-destructive technique of neutron diffraction.The thermal model takes into account the moving heat source in the V-shaped weld. The heat source is modelled by filler material being added continuously in connection with a body flux. In order to obtain a more realistic weld......Butt-welding in one pass with SMAW of two 10mm mild steel plates is investigated. In order to predict the residual stress fields associated with the welding procedure, a finite element model in 3D has been developed in ABAQUS. This model applies a sequential thermal and mechanical numerical...... analysis. In order to evaluate and refine the model parameters for the thermal analysis, the numerical results from this analysis are compared with experimental measurements of the temperature. To evaluate the predicted stress/strain fields, the mechanical model has been validated experimentally. This has...

  2. Computer and experimental analyses of the stress state in the cement hip joint endoprosthesis body.

    Science.gov (United States)

    Tabaković, Slobodan; Grujić, Jovan; Zeljković, Milan; Blagojević, Zoran; Radojević, Bojan; Popović, Zoran; Zivković, Aleksandar; Stevanović, Vladan

    2014-11-01

    One of the possible complications after implantation of a cement hip-joint endoprosthesis is frac- ture in the endoprosthesis body. Fractures arise from overload or material fatigue of which an implant is made. The purpose of this research was to define the intensity of maximum stress and the positions of a critical cross-section in the endoprosthesis body. Unilaterally changing forces which act on the hip joint during walking as well as the loads result in flexible deformations of the endoprosthesis body. Biomechanical analysis of the forces acting on the hip joint determine their direction and intensity, whereas on the basis of Gruen's classification of the endoprosthesis body loosening the level of fixation is established. The bodies of cement hip joint endoprosthesis are made of cobalt-chromium-molybdenum (CoCrMo) alloy, suitable for vacuum casting, are submitted to the analysis. Analysis of the critical stress in the endoprosthesis body was performed on the endoprosthesis body by means of the finite element method. The experimental verification of the obtained results was carried out on the physical prototype under laboratory conditions. Computer analysis, by means of the finite element method, determined the stress state by calculation of the maximum Von Mises stress and critical cross-sections for different angles of the resultant force action. The results obtained by the computer and experimental method correlate and are comparable to the results of similar analyses conducted on various endoprosthesis types. The analyses described in the paper make the basis for improving the process designing of hip joint endoprostheses and their customization to each individual patient (custom made).

  3. Ordination techniques for analysing response of biological communities to toxic stress in experimental ecosystems.

    NARCIS (Netherlands)

    Wijngaarden, van R.P.A.; Brink, van den P.J.; Oude Voshaar, J.H.; Leeuwangh, P.

    1995-01-01

    The ordination techniques Principal Component Analysis (PCA) and Redundancy Analysis (RDA) are considered to be useful tools for evaluating community responses in experimental ecotoxicology. Concepts and interpretation of these techniques are summarized. Application of PCA and RDA is illustrated in

  4. A combination of experimental and finite element analyses of needle-tissue interaction to compute the stresses and deformations during injection at different angles.

    Science.gov (United States)

    Halabian, Mahdi; Beigzadeh, Borhan; Karimi, Alireza; Shirazi, Hadi Asgharzadeh; Shaali, Mohammad Hasan

    2016-12-01

    One of the main clinical applications of the needles is its practical usage in the femoral vein catheterization. Annually more than two million peoples in the United States are exposed to femoral vein catheterization. How to use the input needles into the femoral vein has a key role in the sense of pain in post-injection and possible injuries, such as tissue damage and bleeding. It has been shown that there might be a correlation between the stresses and deformations due to femoral injection to the tissue and the sense of pain and, consequently, injuries caused by needles. In this study, the stresses and deformations induced by the needle to the femoral tissue were experimentally and numerically investigated in response to an input needle at four different angles, i.e., 30°, 45°, 60°, and 90°, via finite element method. In addition, a set of experimental injections at different angles were carried out to compare the numerical results with that of the experimental ones, namely pain score. The results revealed that by increasing the angle of injection up to 60°, the strain at the interaction site of the needle-tissue is increased accordingly while a significant falling is observed at the angle of 90°. In contrast, the stress due to injection was decreased at the region of needle-tissue interaction with showing the lowest one at the angle of 90°. Experimental results were also well confirmed the numerical observations since the lowest pain score was seen at the angle of 90°. The results suggest that the most effective angle of injection would be 90° due to a lower amount of stresses and deformations compared to the other angles of injection. These findings may have implications not only for understating the stresses and deformations induced during injection around the needle-tissue interaction, but also to give an outlook to the doctors to implement the most suitable angle of injection in order to reduce the pain as well as post injury of the patients.

  5. Inelastic and Dynamic Fracture and Stress Analyses

    Science.gov (United States)

    Atluri, S. N.

    1984-01-01

    Large deformation inelastic stress analysis and inelastic and dynamic crack propagation research work is summarized. The salient topics of interest in engine structure analysis that are discussed herein include: (1) a path-independent integral (T) in inelastic fracture mechanics, (2) analysis of dynamic crack propagation, (3) generalization of constitutive relations of inelasticity for finite deformations , (4) complementary energy approaches in inelastic analyses, and (5) objectivity of time integration schemes in inelastic stress analysis.

  6. Finite element analyses of tool stresses in metal cutting processes

    Energy Technology Data Exchange (ETDEWEB)

    Kistler, B.L. [Sandia National Labs., Livermore, CA (United States)

    1997-01-01

    In this report, we analytically predict and examine stresses in tool tips used in high speed orthogonal machining operations. Specifically, one analysis was compared to an existing experimental measurement of stresses in a sapphire tool tip cutting 1020 steel at slow speeds. In addition, two analyses were done of a carbide tool tip in a machining process at higher cutting speeds, in order to compare to experimental results produced as part of this study. The metal being cut was simulated using a Sandia developed damage plasticity material model, which allowed the cutting to occur analytically without prespecifying the line of cutting/failure. The latter analyses incorporated temperature effects on the tool tip. Calculated tool forces and peak stresses matched experimental data to within 20%. Stress contours generally agreed between analysis and experiment. This work could be extended to investigate/predict failures in the tool tip, which would be of great interest to machining shops in understanding how to optimize cost/retooling time.

  7. Development and Analyses of the Coping Stress Inventory

    Science.gov (United States)

    Gadzella, Bernadette M.; Pierce, Devin; Young, Adena

    2008-01-01

    This is a report on the development of a coping stress inventory and the analyses of the data collected from 344 participants. The Coping Stress Inventory, CSI, with 16 items intercorrelated in the categories (Behavioral, Emotional, and Cognitive Appraisal). The internal consistency for the CSI was 0.77. Responses to the CSI were compared (a)…

  8. Interferon-¿ regulates oxidative stress during experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Espejo, C.; Penkowa, Milena; Saez-Torres, I.

    2002-01-01

    Neurobiology, experimental autoimmune encephalomyelitis IFN-d, multiple sclerosis, neurodegeneration, oxidative stress......Neurobiology, experimental autoimmune encephalomyelitis IFN-d, multiple sclerosis, neurodegeneration, oxidative stress...

  9. Experimentally Induced Stress Validated by EMG Activity

    Science.gov (United States)

    Luijcks, Rosan; Hermens, Hermie J.; Bodar, Lonneke; Vossen, Catherine J.; Os, Jim van.; Lousberg, Richel

    2014-01-01

    Experience of stress may lead to increased electromyography (EMG) activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies. PMID:24736740

  10. Experimentally induced stress validated by EMG activity.

    Science.gov (United States)

    Luijcks, Rosan; Hermens, Hermie J; Bodar, Lonneke; Vossen, Catherine J; Van Os, Jim; Lousberg, Richel

    2014-01-01

    Experience of stress may lead to increased electromyography (EMG) activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.

  11. Experimentally induced stress validated by EMG activity.

    Directory of Open Access Journals (Sweden)

    Rosan Luijcks

    Full Text Available Experience of stress may lead to increased electromyography (EMG activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.

  12. Experimental Measurement of In Situ Stress

    Science.gov (United States)

    Tibbo, Maria; Milkereit, Bernd; Nasseri, Farzine; Schmitt, Douglas; Young, Paul

    2016-04-01

    of hydrostatic stress (σ1 = σ2 = σ3), differential stress (σ1 > σ2 = σ3), and the unique true triaxial stress (σ1 > σ2 > σ3). Velocity surveys can be acquired along all three axes, and therefore the effects of σ1,σ2,σ3 on the velocity-stress curve can be obtained. These geophysical cells are being used to reproduce the borehole P- and S-wave velocities by altering the differential stress, allowing for the unique position of determining the stress tensor. Currently, results have been obtained for differential stress (σ1 > σ2 = σ3), and true triaxial experiments will determine if σ3 is the missing factor to reproducing the borehole velocities. This project is the first to combine time - lapse borehole logging data and experimental laboratory data to infer a complete stress tensor.

  13. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Stress Analyses Definitions B Appendix B to Part 154 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Pt. 154, App. B Appendix B to Part 154...

  14. Experimental Analyses for The Mechanical Behavior of Pressed All-Ceramic Molar Crowns with Anatomical Design

    OpenAIRE

    Porojan Liliana; Porojan Sorin; Rusu Lucian; Boloş Adrian; Savencu Cristina

    2017-01-01

    Ceramic restorations show considerable variation in strength and structural reliability regarding to the type of material, and design characteristics. The fracture of ceramics occurs with little or no plastic deformation, with cracks propagated in an unstable manner under applied tensile stresses. The aim of the study was to assess experimental analyses of pressed monolithic ceramic crowns with anatomical design used in the posterior areas in order to understand their mechanical behavior befo...

  15. Analyses of the OSU-MASLWR Experimental Test Facility

    Directory of Open Access Journals (Sweden)

    F. Mascari

    2012-01-01

    Full Text Available Today, considering the sustainability of the nuclear technology in the energy mix policy of developing and developed countries, the international community starts the development of new advanced reactor designs. In this framework, Oregon State University (OSU has constructed, a system level test facility to examine natural circulation phenomena of importance to multi-application small light water reactor (MASLWR design, a small modular pressurized water reactor (PWR, relying on natural circulation during both steady-state and transient operation. The target of this paper is to give a review of the main characteristics of the experimental facility, to analyse the main phenomena characterizing the tests already performed, the potential transients that could be investigated in the facility, and to describe the current IAEA International Collaborative Standard Problem that is being hosted at OSU and the experimental data will be collected at the OSU-MASLWR test facility. A summary of the best estimate thermal hydraulic system code analyses, already performed, to analyze the codes capability in predicting the phenomena typical of the MASLWR prototype, thermal hydraulically characterized in the OSU-MASLWR facility, is presented as well.

  16. Effect of direct current sputtering power on the behavior of amorphous indium-gallium-zinc-oxide thin-film transistors under negative bias illumination stress: A combination of experimental analyses and device simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jun Tae; Kim, Dong Myong; Choi, Sung-Jin; Kim, Dae Hwan, E-mail: khs3297@cnu.ac.kr, E-mail: drlife@kookmin.ac.kr [School of Electrical Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of); Park, Jozeph [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Ahn, Byung Du [School of Electrical and Electronic Engineering, Yonsei University, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Kim, Hyun-Suk, E-mail: khs3297@cnu.ac.kr, E-mail: drlife@kookmin.ac.kr [Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2015-03-23

    The effect of direct current sputtering power of indium-gallium-zinc-oxide (IGZO) on the performance and stability of the corresponding thin-film transistor devices was studied. The field effect mobility increases as the IGZO sputter power increases, at the expense of device reliability under negative bias illumination stress (NBIS). Device simulation based on the extracted sub-gap density of states indicates that the field effect mobility is improved as a result of the number of acceptor-like states decreasing. The degradation by NBIS is suggested to be induced by the formation of peroxides in IGZO rather than charge trapping.

  17. Analyses of spatial variations of kenaf in experimental field

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-08

    Mar 8, 2010 ... Preliminary investigations of experimental field usually involve collection of soil samples at widely spaced locations which are patchily or globally at variant spatially. This study was carried out to evaluate spatial variations in experimental fields using a split plot experiment distributed in a completely ...

  18. Analyses of spatial variations of kenaf in experimental field | Dauda ...

    African Journals Online (AJOL)

    Preliminary investigations of experimental field usually involve collection of soil samples at widely spaced locations which are patchily or globally at variant spatially. This study was carried out to evaluate spatial variations in experimental fields using a split plot experiment distributed in a completely randomized design at ...

  19. Experimental analyses of dynamical systems involving shape memory alloys

    DEFF Research Database (Denmark)

    Enemark, Søren; Savi, Marcelo A.; Santos, Ilmar F.

    2015-01-01

    The use of shape memory alloys (SMAs) in dynamical systems has an increasing importance in engineering especially due to their capacity to provide vibration reductions. In this regard, experimental tests are essential in order to show all potentialities of this kind of systems. In this work, SMA...... springs are incorporated in a dynamical system that consists of a one degree of freedom oscillator connected to a linear spring and a mass, which is also connected to the SMA spring. Two types of springs are investigated defming two distinct systems: a pseudoelastic and a shape memory system......-tension of the springs. This article shows several experimental tests that allow one to obtain a general comprehension of the dynamical behaviour of SMA systems. Results show the general thermo-mechanical behaviour of SMA dynamical systems and the obtained conclusions can be applied in distinct situations as in rotor...

  20. Study on analyses of experimental data at DCA

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung Joo; Suk, Ho Chun; Hazama, T. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    In this report, the lattice characteristics of DCA are calculated to validate WIMS-AECL code for the lattice analysis of CANDU core by using experimental data of DCA and JNC. These results are compared with those of WIMS-ATR code. Analytical studies of some critical experiments had been performed to analyze the effects of fuel composition and lattice pitch. Different items of reactor physics such as local power peaking factor (LPF), effective multiplication factor (Keff) and coolant void reactivity were calculated for two coolant void fractions (0% and 100%). LPFs calculated by WIMS-ATR code are in close agreement with the experimental results. LPFs calculated by WIMS-AECL code with WINFRITH and ENDF/B-V libraries have similar values for both libraries but the differences between experimental data and results of WIMS-AECL code are larger than those of WIMS-ATR code. The maximum difference between the values calculated by WIMS-ATR and experimental values of LPFs are within 1.3%. LPF of Pu fuel cluster is found to be higher than that of the uranium fuel cluster. The coupled code systems WIMS-ATR and CITATION used in this analysis predict Keff within 1% {delta}K and coolant void reactivity within 4%{delta}K/K in all cases. The coolant void reactivity of uranium fuel is found to be positive for two lattice pitches (25.0 and 28.3 cm). Presence of plutonium fuel makes it more negative compare to uranium fuel. To validate WIMS-AECL code, the core characteristics of DCA shall be calculated by WIMS-AECL and CITATION codes in the future. 8 refs., 8 figs., 12 tabs. (Author)

  1. Analytical and Experimental Study of Residual Stresses in CFRP

    Directory of Open Access Journals (Sweden)

    Chia-Chin Chiang

    2013-01-01

    Full Text Available Fiber Bragg Grating sensors (FBGs have been utilized in various engineering and photoelectric fields because of their good environment tolerance. In this research, residual stresses of carbon fiber reinforced polymer composites (CFRP were studied using both experimental and analytical approach. The FBGs were embedded inside middle layers of CFRP to study the formation of residual stress during curing process. Finite element analysis was performed using ABAQUS software to simulate the CFRP curing process. Both experimental and simulation results showed that the residual stress appeared during cooling process and the residual stresses could be released when the CFRP was machined to a different shape.

  2. Review of accident analyses of RB experimental reactor

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2003-01-01

    Full Text Available The RB reactor is a uranium fuel heavy water moderated critical assembly that has been put and kept in operation by the VTNCA Institute of Nuclear Sciences, Belgrade, Serbia and Montenegro, since April 1958. The first complete Safety Analysis Report of the RB reactor was prepared in 1961/62 yet, the first accident analysis had been made in late 1958 with the aim to examine a power transition and the total equivalent doses received by the staff during the reactivity accident that occurred on October 15, 1958. Since 1960, the RB reactor has been modified a few times. Beside the initial natural uranium metal fuel rods, new types of fuel (TVR-S types of Russian origin consisting of 2% enriched uranium metal and 80% enriched UO2 dispersed in aluminum matrix, have been available since 1962 and 1976 respectively. Modifications of the control and safety systems of the reactor were made occasionally. Special reactor cores were designed and constructed using all three types of fuel elements as well as the coupled fast-thermal ones. The Nuclear Safety Committee of the VINĆA Institute, an independent regulatory body, approved for usage all these modifications of the RB reactor on the basis of the Preliminary Safety Analysis Reports, which, beside proposed technical modifications and new regulation rules, included safety analyses of various possible accidents. A special attention was given (and a new safety methodology was proposed to thorough analyses of the design-based accidents related to the coupled fast-thermal cores that included central zones of the reactor filled by the fuel elements without any moderator. In this paper, an overview of some accidents, methodologies and computation tools used for the accident analyses of the RB reactor is given.

  3. Hybrid Experimental-Numerical Stress Analysis.

    Science.gov (United States)

    1983-04-01

    A. 1. and Riley# W. F., Introduction to Pho hanics, Pren- tics -Hall, Englewood Cliffs# 1965P pp. 185-186. 8. Rao, G. V., "Experimental-numerical...Naw1 o a. CA *924 Loe Amnl*&. Ca 10024 Profesor T. V. Cosng Or. IF. Sm#Amv Or. M. P. gtesProfeesr Ulert pried University of Agree on"ser si pmlo

  4. Experimental Determination of Stress Intensity in a Cracked Cylindrical Specimen,

    Science.gov (United States)

    1980-05-01

    CRACKED CYLINDRICAL SPEC IMEN 7 ABSTRACT The range of stress intensity at the tip of a fatigue crack is the major factor controlling the crack growth...of this report will be similarly clesiied): The range of stress intensity at the tip of a fatigue crack is the major factor controlling the crack...EXPERIMENTAL STRESS INTENSITY CALIBRATION 3 3. EXPERIMENTAL DETAILS 4 3.1 Specimen Geometries 4 3.2 Material 5 3.3 Fatigue Loading 5 3.4 Crack Length

  5. Experimental characterization of stress relaxation in glass

    Science.gov (United States)

    Kadali, Hemanth C.

    Glass viscoelasticity has gained importance in recent years as glass lens molding appeared as a valuable alternative to the traditional grinding and polishing process for manufacturing glass lenses. In the precision lens molding process, knowledge of viscoelastic properties of glass in the transition region, which affect the stress relaxation behavior, is required to precisely predict the final size and shape of molded lenses. The purpose of this study is to establish a step-by-step procedure for characterizing the viscoelastic behavior of glass in the glass transition region using a finite term Prony series of a Generalized Maxwell model. This study focuses on viscoelastic characterization of stabilized glass samples at lower stress levels between 3 and 12 MPa where it demonstrates linearity. Analysis and post-processing of creep data, performed in MATLAB and MAPLE, include displacement-to-strain conversion, determination of viscoelastic moments and constants, normalization, curve fitting and retardation-to-relaxation conversion. The process of curve fitting is carried out using a constrained optimization scheme to satisfy the constraint equations involving viscoelastic constants and functions. A set of relaxation parameters needed in numerical modeling, i.e., weights and times of the Prony series are presented in this thesis for borosilicate glass at different temperatures. Additionally, the issues related to the characterization of optical glasses were identified and discussed.

  6. Method for analysing the deformation and stress of vertebra assembly

    Directory of Open Access Journals (Sweden)

    Spanu Alina Rodica

    2017-01-01

    Full Text Available The paper presents a method for testing the deformation and stress values of the vertebra assembly when variable forces are applied on the body surface. The working points have very well-known positions and they could be changed, so the compression force, torsional or bending couples could act. The system is actuated by an electrical stepper motor controlled with Arduino. The force and displacement sensors were used.

  7. Data for transcriptomic and proteomic analyses of leaves from Clematis terniflora DC. under binary stress

    Directory of Open Access Journals (Sweden)

    Bingxian Yang

    2017-06-01

    Full Text Available High level of UV-B irradiation followed by dark treatment accumulates secondary metabolites in Clematis terniflora DC. To investigate the response mechanism under high level of UV-B irradiation followed by dark treatment, transcriptomic and proteomic analyses were performed in leaves of Clematis terniflora DC. The experimental design for the transcriptomic and proteomic analyses in leaves of C. terniflora under stresses was organized into a picture. For transcriptomics, mRNA-sequencing technology was used. Genes identified in leaves of C. terniflora at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were listed; genes with different expression levels at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were also presented in this DiB article. For proteomics, a gel-free/label-free proteomic technique was used. Proteins with different abundances in leaves at starting point, high level of UV-B irradiation, and high level of UV-B irradiation followed by dark treatment were presented in this DiB article. In order to monitor the expression levels of genes under the stress, quantitative reverse transcription polymerase chain reaction was performed. The primer sequences of genes selected for quantitative reverse transcription polymerase chain reaction was presented in this DiB article.

  8. Influence of Radial Stress Gradient on Strainbursts: An Experimental Study

    Science.gov (United States)

    Su, Guoshao; Zhai, Shaobin; Jiang, Jianqing; Zhang, Gangliang; Yan, Liubin

    2017-10-01

    Strainbursts, which are violent disasters that are accompanied by the ejection failure of rocks, usually occur in hard brittle rocks around highly stressed underground openings. The release of the radial stress at excavation boundaries is one of the major inducing factors for strainbursts in tunnels. After excavation, the radial stress usually exhibits different but apparent gradient variations along the radial direction near the boundary within a certain depth under different in situ stress conditions. In this study, the influence of the radial stress gradient on strainbursts of granite was investigated using an improved true-triaxial rockburst testing system, which was equipped with an acoustic emission monitoring system. The stress state and boundary conditions (i.e., one face free, other faces loaded and increasing tangential stress) of the representative rock element in the vicinity of the excavation boundary were simulated. High-speed cameras were used to capture the ejection failure processes during strainbursts, and the kinetic energy of ejected fragments was quantitatively estimated by analyzing the recorded videos. The experimental results indicate that with an increasing radial stress gradient, the strength increases, the apparent yield platform prior to the peak stress on the stress-strain curves decreases, the failure mode changes from strainburst characterized by tensile splitting to strainburst characterized by shear rupture, and the kinetic energy of ejected fragments during strainbursts significantly increases.

  9. Stress and free vibration analyses of multilayered composite plates

    Science.gov (United States)

    Noor, Ahmed K.; Burton, W. Scott

    1989-01-01

    This paper presents a two-phase computational procedure for the accurate prediction of vibration frequencies, stresses, and deformations in simply supported bidirectional multilayered composite plates. The range of applicability of this procedure in terms of the plate's parameters is determined, and the potential of the proposed procedure for use in conjunction with large-scale finite element modeling of composite structures is discussed. It is shown that the use of the shear correction factors calculated by this procedure extends the range of the validity of the first-order shear deformation theory, used in the first phase of the procedure, to fairly thick multilayered plates with the h/L1 ratio of the order of 0.3.

  10. Economic analyses of stress urinary incontinence surgical procedures in women.

    Science.gov (United States)

    Rawlings, Tanner; Zimmern, Philippe E

    2016-11-01

    To evaluate the quality of economic analysis (EA) of surgical procedures for stress urinary incontinence (SUI) in women. A MEDLINE search on EA for SUI surgical procedures for the years 2000-2014 included the MeSH terms "tension-free vaginal tape," "TVT," "trans-obturator tape," "TOT," "Burch colposuspension" (BC), "stress urinary incontinence," "economic analysis," and "cost-effectiveness analysis." Important criteria for evaluating articles were selected from panels that set out criteria to evaluate EA [Scales CD, Jr., Christopher SS, American Urological Association 32:121-128, 2013], [Hsieh MH, Maxwell MV, J Urol 178 1867-1874, 2007], [Wu JM, Catherine CM, Conover MM, et al., Obstet Gynecol 123 1201-1206, 2014]. Thirteen articles were identified: TVT compared to BC (6), to other surgical procedures for SUI (1), to TOT (3) and to the mini-sling (1); open BC compared to laparoscopic BC (1), and analysis of various slings and meshes for various types of incontinence (1). Articles originated from: United States (3), Europe (4), United Kingdom (4), and Canada (2). Eight described cost-effectiveness analysis (CEA), two cost-utility analysis, and three cost comparison. Follow-up time for patients ranged from 6 to 24 months in eight articles, with four having a minimum of 24 months follow-up. Studies mostly adhered to the criteria, however indirect costs, sensitivity analysis, and efficacy parameters varied. Long-term synthetic sling-related complications were not included. Although CEA for SUI surgery is a burgeoning field, study comparisons remain difficult due to some variability, including health care delivery systems. As women live longer, long-term data will become critical as complications and reoperations can affect the real cost of SUI corrective procedures. Neurourol. Urodynam. 35:1040-1045, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  11. Experimental stress analysis for materials and structures stress analysis models for developing design methodologies

    CERN Document Server

    Freddi, Alessandro; Cristofolini, Luca

    2015-01-01

    This book summarizes the main methods of experimental stress analysis and examines their application to various states of stress of major technical interest, highlighting aspects not always covered in the classic literature. It is explained how experimental stress analysis assists in the verification and completion of analytical and numerical models, the development of phenomenological theories, the measurement and control of system parameters under operating conditions, and identification of causes of failure or malfunction. Cases addressed include measurement of the state of stress in models, measurement of actual loads on structures, verification of stress states in circumstances of complex numerical modeling, assessment of stress-related material damage, and reliability analysis of artifacts (e.g. prostheses) that interact with biological systems. The book will serve graduate students and professionals as a valuable tool for finding solutions when analytical solutions do not exist.

  12. Improved assumed-stress hybrid shell element with drilling degrees of freedom for linear stress, buckling, and free vibration analyses

    Science.gov (United States)

    Rengarajan, Govind; Aminpour, Mohammad A.; Knight, Norman F., Jr.

    1992-01-01

    An improved four-node quadrilateral assumed-stress hybrid shell element with drilling degrees of freedom is presented. The formulation is based on Hellinger-Reissner variational principle and the shape functions are formulated directly for the four-node element. The element has 12 membrane degrees of freedom and 12 bending degrees of freedom. It has nine independent stress parameters to describe the membrane stress resultant field and 13 independent stress parameters to describe the moment and transverse shear stress resultant field. The formulation encompasses linear stress, linear buckling, and linear free vibration problems. The element is validated with standard tests cases and is shown to be robust. Numerical results are presented for linear stress, buckling, and free vibration analyses.

  13. Numerical and Experimental Study on Residual Stress in Gray Cast Iron Stress Lattice Shape Casting

    Science.gov (United States)

    Motoyama, Yuichi; Takahashi, Hiroki; Okane, Toshimitsu; Fukuda, Yoya; Yoshida, Makoto

    2013-07-01

    The prediction of residual stress in a stress lattice shape casting (stress lattice) has been conducted and discussed by some researchers via the Finite Element Method (FEM). However, most of the previous studies used the first-order tetrahedral element, which has poor analysis accuracy in problems including bending. The use of the first-order tetrahedral element makes the verification of these studies uncertain because the bending deformation essentially occurs in the stress lattice casting. This study first shows that the thermal stress analysis for the stress lattice should use the element that can represent the bending deformation in principle for bending of the thin parts. Second, the simulated residual stress was compared with the measured value. The thermal stress analysis successfully predicted the residual stress of the stress lattice casting with and 11 pct difference. In addition to the prediction of the residual stress, it is important from the viewpoint of the productivity of castings to reveal the effect of the shake-out temperature on the residual stress. However, in the previous studies, conclusions concerning the effect of the shake-out temperature on the residual stress were not consistent ( i.e., the one study said the higher shake-out temperature decreased the residual stress, and another study said a higher shake-out temperature increased the residual stress). Therefore, the current study first discusses the reason for the inconsistent conclusions in the previous studies. Second, stress lattice castings were cast and shaken out at various shake-out temperatures. Then, the current study validated the effect of the shake-out temperature on the residual stress. Consequently, the experimental results supported the conclusion of Kasch and Mikelonis that the shake-out at higher temperature contributed to the increase of the residual stress in the casting.

  14. Experimental Analyses for The Mechanical Behavior of Pressed All-Ceramic Molar Crowns with Anatomical Design

    Directory of Open Access Journals (Sweden)

    Porojan Liliana

    2017-01-01

    Full Text Available Ceramic restorations show considerable variation in strength and structural reliability regarding to the type of material, and design characteristics. The fracture of ceramics occurs with little or no plastic deformation, with cracks propagated in an unstable manner under applied tensile stresses. The aim of the study was to assess experimental analyses of pressed monolithic ceramic crowns with anatomical design used in the posterior areas in order to understand their mechanical behavior before following their clinical use. Experiments were conducted on a complete molar crown preparation. Experiments show different modes of fracture for the tested samples. Digital images from the fractured pieces of the crowns were used to verify the fragments in all cases final fracture occurred by splitting into two and often more parts. The graphically representation of the displacement depending on the load highlights a series of peaks that can be correlated with cracks occurred in crowns. The development of well-designed mechanical experiments could be useful to help to predict clinical survival of these new all-ceramic restorative techniques and materials. Because failure is often accompanied by complete cracking of the crowns, preliminary research should represents a compulsory goal.

  15. Experimental investigation of system effects in stressed-skin elements

    DEFF Research Database (Denmark)

    Dela Stang, B.; Isaksson, T.; Hansson, M.

    What kind of behaviour can be expected from stressed-skin elements at failure? To answer this question was a primary objective of the experimental investigation presented in this report. Systems of 3 roof units, each made of 5 parallel beams, have been tested for load-carrying capacity...

  16. Analyse

    DEFF Research Database (Denmark)

    Greve, Bent

    2007-01-01

    Analyse i Politiken om frynsegoder med udgangspunkt i bogen Occupational Welfare - Winners and Losers publiceret på Edward Elgar......Analyse i Politiken om frynsegoder med udgangspunkt i bogen Occupational Welfare - Winners and Losers publiceret på Edward Elgar...

  17. Round Robin Analyses on Stress Intensity Factors of Inner Surface Cracks in Welded Stainless Steel Pipes

    Directory of Open Access Journals (Sweden)

    Chang-Gi Han

    2016-12-01

    Full Text Available Austenitic stainless steels (ASSs are widely used for nuclear pipes as they exhibit a good combination of mechanical properties and corrosion resistance. However, high tensile residual stresses may occur in ASS welds because postweld heat treatment is not generally conducted in order to avoid sensitization, which causes a stress corrosion crack. In this study, round robin analyses on stress intensity factors (SIFs were carried out to examine the appropriateness of structural integrity assessment methods for ASS pipe welds with two types of circumferential cracks. Typical stress profiles were generated from finite element analyses by considering residual stresses and normal operating conditions. Then, SIFs of cracked ASS pipes were determined by analytical equations represented in fitness-for-service assessment codes as well as reference finite element analyses. The discrepancies of estimated SIFs among round robin participants were confirmed due to different assessment procedures and relevant considerations, as well as the mistakes of participants. The effects of uncertainty factors on SIFs were deducted from sensitivity analyses and, based on the similarity and conservatism compared with detailed finite element analysis results, the R6 code, taking into account the applied internal pressure and combination of stress components, was recommended as the optimum procedure for SIF estimation.

  18. Thermal stress analyses of a header plate with a 51-PIN electrical feed-thru

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, V.L.; McCollister, H.L.

    1992-12-31

    An electronic package currently under development requires a hermetically-sealed electrical connection through a metal header plate. The electrical feedthru consists of 51 RA333 pins in an S-type glass ceramic insulator. Because the feedthru contains a large number of pins spaced closely together, a single glass preform rather than individual glass beads at each pin has been proposed. Finite element analyses were conducted to gain insight into the stress distribution in the header plate, glass, and pins. To verify the finite element analyses, a prototype part was manufactured and examined for cracking in the glass ceramic and for leakage of the glass-to-metal seal. Finite element analyses were then used to investigate effects of the plate geometry and yield strength on stresses in the assembly. This paper illustrates one way that finite element analyses can be used along with selective prototype manufacturing for a timely and cost-effective method of evaluating design parameters of electronic packages.

  19. Family structure and posttraumatic stress reactions: a longitudinal study using multilevel analyses

    Directory of Open Access Journals (Sweden)

    Nygaard Egil

    2011-12-01

    Full Text Available Abstract Background There is limited research on the relevance of family structures to the development and maintenance of posttraumatic stress following disasters. We longitudinally studied the effects of marital and parental statuses on posttraumatic stress reactions after the 2004 Southeast Asian tsunami and whether persons in the same households had more shared stress reactions than others. Method The study included a tourist population of 641 Norwegian adult citizens, many of them from families with children. We measured posttraumatic stress symptoms with the Impact of Event Scale-Revised at 6 months and 2 years post-disaster. Analyses included multilevel methods with mixed effects models. Results Results showed that neither marital nor parental status was significantly related to posttraumatic stress. At both assessments, adults living in the same household reported levels of posttraumatic stress that were more similar to one another than adults who were not living together. Between households, disaster experiences were closely related to the variance in posttraumatic stress symptom levels at both assessments. Within households, however, disaster experiences were less related to the variance in symptom level at 2 years than at 6 months. Conclusions These results indicate that adult household members may influence one another's posttraumatic stress reactions as well as their interpretations of the disaster experiences over time. Our findings suggest that multilevel methods may provide important information about family processes after disasters.

  20. Evaluation of Algebraic Reynolds Stress Model Assumptions Using Experimental Data

    Science.gov (United States)

    Jyoti, B.; Ewing, D.; Matovic, D.

    1996-11-01

    The accuracy of Rodi's ASM assumption is examined by evaluating the terms in Reynolds stress transport equation and their modelled counterparts. The basic model assumption: Dτ_ij/Dt + partial T_ijl/partial xl = (τ_ij/k )(Dk/Dt + partial Tl /partial xl ) (Rodi( Rodi W., ZAMM.), 56, pp. 219-221, 1976.), can also be broken into two stronger assumptions: Da_ij/Dt = 0 and (2) partial T_ijl/partial xl = (τ_ij/k )(partial Tl /partial xl ) (e.g. Taulbee( Taulbee D. B., Phys. of Fluids), 4(11), pp. 2555-2561, 1992.). Fu et al( Fu S., Huang P.G., Launder B.E. & Leschziner M.A., J. Fluid Eng.), 110(2), pp. 216-221., 1988 examined the accuracy of Rodi's assumption using the results of RSM calculation of axisymmetric jets. Since the RSM results did not accurately predict the experimental results either, it may be useful to examine the basic ASM model assumptions using experimental data. The database of Hussein, Capp and George( Hussein H., Capp S. & George W., J.F.M.), 258, pp.31-75., 1994. is sufficiently detailed to evaluate the terms of Reynolds stress transport equations individually, thus allowing both Rodi's and the stronger assumptions to be tested. For this flow assumption (1) is well satisfied for all the components (including \\overlineuv); however, assumption (2) does not seem as well satisfied.

  1. Experimentally testing Taylor's stress, coping and adaptation framework.

    Science.gov (United States)

    Gidron, Yori; Nyklicek, Ivan

    2009-10-01

    Taylor (1995) constructed a comprehensive framework of stress and adaptation, which considers internal and external resources/impediments as moderators, based on previous studies and models. However, most past research used correlation designs and has not taken into account all of the framework's components within one study. This study tested the effects of the event (minor, major), primary appraisal (benign, severe), coping (problem-focused coping (PFC) versus emotion-focused coping), external resources (with/without social support), and internal impediments (hostility), on estimated distress (dependent variable) in written imagined stressful daily scenarios. All components except hostility were experimentally manipulated within subjects in the scenarios. The scenarios were rated by 281 Dutch students. The variables event, appraisal, and social support significantly and independently affected estimated distress. Event and appraisal synergistically interacted in relation to estimated distress. Finally, appraisal interacted with coping such that the distress-reducing effects of PFC occurred only in benign events, while coping did not affect estimated distress in severely appraised events. This study experimentally tested most components of Taylor's framework, and showed that events, appraisal, and social resources were independent determinants of estimated distress, and that appraisal interacts in a complex manner with the event and with coping.

  2. Preliminary analysing of experimental data for the development of high Cr Alloy Creep damage Constitutive Equations

    OpenAIRE

    An, Lili; Xu, Qiang; Xu, Donglai; Lu, Zhongyu

    2012-01-01

    This conference paper presents the current research of preliminary analysing of experimental data for the development of high Cr Alloy Creep damage Constitutive Equations (such as P91 alloy). Firstly, it briefly introduces the background of general creep deformation, rupture and continuum damage mechanics. Secondly, it illustrates the constitutive equations used for P91 alloy or its weldment, especially of the form and deficiencies of two kinds of most widely used typical creep damage constit...

  3. Comparison between theoretical analyses and experimental results of two-phase closed thermosyphons solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Sayegh, M.A. [Faculty of Mechanical Engineering, Univ. Aleppo (Syrian Arab Republic); Danielewicz, J.; Nowak, B. [Faculty of Heating and Air Conditioning, Techn. Univ. of Wroclaw (Poland)

    1996-12-31

    The observed experimental results of the heated water temperature runs in the solar collector with TPCT for water heating systems are compared with results of numerical simulation. A compact system for hot water preparation with absorbing and accumulating the heat was analysed. In study the influence of the thermal resistance of TPCT on the heat removal factor F{sub R} and collector thermal efficiency is also presented. (orig.)

  4. Methodological quality of meta-analyses of single-case experimental studies.

    Science.gov (United States)

    Jamshidi, Laleh; Heyvaert, Mieke; Declercq, Lies; Fernández-Castilla, Belén; Ferron, John M; Moeyaert, Mariola; Beretvas, S Natasha; Onghena, Patrick; Van den Noortgate, Wim

    2017-12-28

    Methodological rigor is a fundamental factor in the validity and credibility of the results of a meta-analysis. Following an increasing interest in single-case experimental design (SCED) meta-analyses, the current study investigates the methodological quality of SCED meta-analyses. We assessed the methodological quality of 178 SCED meta-analyses published between 1985 and 2015 through the modified Revised-Assessment of Multiple Systematic Reviews (R-AMSTAR) checklist. The main finding of the current review is that the methodological quality of the SCED meta-analyses has increased over time, but is still low according to the R-AMSTAR checklist. A remarkable percentage of the studies (93.80% of the included SCED meta-analyses) did not even reach the midpoint score (22, on a scale of 0-44). The mean and median methodological quality scores were 15.57 and 16, respectively. Relatively high scores were observed for "providing the characteristics of the included studies" and "doing comprehensive literature search". The key areas of deficiency were "reporting an assessment of the likelihood of publication bias" and "using the methods appropriately to combine the findings of studies". Although the results of the current review reveal that the methodological quality of the SCED meta-analyses has increased over time, still more efforts are needed to improve their methodological quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Proteomic and biochemical analyses of the cotyledon and root of flooding-stressed soybean plants.

    Directory of Open Access Journals (Sweden)

    Setsuko Komatsu

    Full Text Available BACKGROUND: Flooding significantly reduces the growth and grain yield of soybean plants. Proteomic and biochemical techniques were used to determine whether the function of cotyledon and root is altered in soybean under flooding stress. RESULTS: Two-day-old soybean plants were flooded for 2 days, after which the proteins from root and cotyledon were extracted for proteomic analysis. In response to flooding stress, the abundance of 73 and 28 proteins was significantly altered in the root and cotyledon, respectively. The accumulation of only one protein, 70 kDa heat shock protein (HSP70 (Glyma17g08020.1, increased in both organs following flooding. The ratio of protein abundance of HSP70 and biophoton emission in the cotyledon was higher than those detected in the root under flooding stress. Computed tomography and elemental analyses revealed that flooding stress decreases the number of calcium oxalate crystal the cotyledon, indicating calcium ion was elevated in the cotyledon under flooding stress. CONCLUSION: These results suggest that calcium might play one role through HSP70 in the cotyledon under flooding stress.

  6. Analyses of layer-thickness effects in bilayered dental ceramics subjected to thermal stresses and ring-on-ring tests

    Energy Technology Data Exchange (ETDEWEB)

    Hsueh, Chun-Hway [ORNL; Thompson, G. A. [U.S. Army Dental and Trauma Research Detachment, Greak Lakes; Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL; Becher, Paul F [ORNL

    2008-01-01

    Objectives. The purpose of this study was to analyze the stress distribution through the thickness of bilayered dental ceramics subjected to both thermal stresses and ring-on-ring tests and to systematically examine how the individual layer thickness influences this stress distribution and the failure origin. Methods. Ring-on-ring tests were performed on In-Ceram Alumina/Vitadur Alpha porcelain bilayered disks with porcelain in the tensile side, and In-Ceram Alumina to porcelain layer thickness ratios of 1:2, 1:1, and 2:1 were used to characterize the failure origins as either surface or interface. Based on the thermomechanical properties and thickness of each layer, the cooling temperature from glass transition temperature, and the ring-on-ring loading configuration, the stress distribution through the thickness of the bilayer was calculated using closed-form solutions. Finite element analyses were also performed to verify the analytical results. Results. The calculated stress distributions showed that the location of maximum tension during testing shifted from the porcelain surface to the In-Ceram Alumina/porcelain interface when the relative layer thickness ratio changed from 1:2 to 1:1 and to 2:1. This trend is in agreement with the experimental observations of the failure origins. Significance. For bilayered dental ceramics subjected to ring-on-ring tests, the location of maximum tension can shift from the surface to the interface depending upon the layer thickness ratio. The closed-form solutions for bilayers subjected to both thermal stresses and ring-on-ring tests are explicitly formulated which allow the biaxial strength of the bilayer to be evaluated.

  7. Proposed Testing to Assess the Accuracy of Glass-To-Metal Seal Stress Analyses.

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, Robert S.; Emery, John M; Tandon, Rajan; Antoun, Bonnie R.; Stavig, Mark E.; Newton, Clay S.; Gibson, Cory S; Bencoe, Denise N.

    2014-09-01

    The material characterization tests conducted on 304L VAR stainless steel and Schott 8061 glass have provided higher fidelity data for calibration of material models used in Glass - T o - Metal (GTM) seal analyses. Specifically, a Thermo - Multi - Linear Elastic Plastic ( thermo - MLEP) material model has be en defined for S S304L and the Simplified Potential Energy Clock nonlinear visc oelastic model has been calibrated for the S8061 glass. To assess the accuracy of finite element stress analyses of GTM seals, a suite of tests are proposed to provide data for comparison to mo del predictions.

  8. Method to simulate and analyse induced stresses for laser crystal packaging technologies.

    Science.gov (United States)

    Ribes-Pleguezuelo, Pol; Zhang, Site; Beckert, Erik; Eberhardt, Ramona; Wyrowski, Frank; Tünnermann, Andreas

    2017-03-20

    A method to simulate induced stresses for a laser crystal packaging technique and the consequent study of birefringent effects inside the laser cavities has been developed. The method has been implemented by thermo-mechanical simulations implemented with ANSYS 17.0. ANSYS results were later imported in VirtualLab Fusion software where input/output beams in terms of wavelengths and polarization were analysed. The study has been built in the context of a low-stress soldering technique implemented for glass or crystal optics packaging's called the solderjet bumping technique. The outcome of the analysis showed almost no difference between the input and output laser beams for the laser cavity constructed with an yttrium aluminum garnet active laser crystal, a second harmonic generator beta-barium borate, and the output laser mirror made of fused silica assembled by the low-stress solderjet bumping technique.

  9. ANALYSE DE LA VOIX DE PILOTES EN SITUATION DE STRESS DANS UN SIMULATEUR DE VOL

    OpenAIRE

    Ruiz, R.; Legros, C.

    1990-01-01

    L'objet de l'étude est l'estimation, par des procédés acoustiques (analyse de la voix) de l'état de stress d'un individu, consécutif à sa soumission à une charge de travail physique ou mentale. Ce premier travail se propose de mesurer les variations de la fréquence fondamentale de voix de pilotes soumis à des incidents de vol en simulateur avion.

  10. Sensitivity of two green microalgae to copper stress: Growth, oxidative and antioxidants analyses.

    Science.gov (United States)

    Hamed, Seham M; Selim, Samy; Klöck, Gerd; AbdElgawad, Hamada

    2017-10-01

    Depending on species, heavy metals, including copper (Cu), differentially affect algal growth and metabolism. Here, we aim to evaluate the differential responses of two green microalgae, Chlorella sorokiniana and Scenedesmus acuminatus, exposed to sub-lethal doses of Cu (25 and 50µM, respectively) for 7 days. The changes in growth, oxidative damage markers, and antioxidants were analysed. We found that S. acuminatus could acclimatise during long-term exposure to Cu stress. S. acuminatus accumulated lower Cu content and showed a slight decrease in H 2 O 2 levels when compared to C. sorokiniana. Cu stress induced membrane damage in the two microalgae species, however, this increase was slightly lower in S. acuminatus. To mitigate Cu stress impact, C. sorkiniana markedly increased proline, polyphenols, flavonoids, tocopherols, glutathione levels, as well as the activities of GST, APX, GR and SOD enzymes, which could explain less-stress sensitivity. On the other hand, S. acuminatus exhibited significant increases in proline, polyphenol, and tocopherol contents. Activity levels of POX, APX, GR and SOD enzymes, were also increased. These results suggest that the two microalgae differentially induced the antioxidant defence system to neutralise the oxidative damage induced by Cu stress. This study also provided new data for Cu tolerance and Cu removal abilities of two microalgal species, which commonly exist in surface water bodies, where low Cu uptake and efficient antioxidant defence system protected S. acuminatus against oxidative stress induced by Cu stress. This makes it feasible for treatment of Cu contaminated waters. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Molecular responses of genetically modified maize to abiotic stresses as determined through proteomic and metabolomic analyses.

    Directory of Open Access Journals (Sweden)

    Rafael Fonseca Benevenuto

    Full Text Available Some genetically modified (GM plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses.

  12. The Early Endocrine Stress Response in Experimental Subarachnoid Hemorrhage.

    Directory of Open Access Journals (Sweden)

    Christoffer Nyberg

    Full Text Available In patients with severe illness, such as aneurysmal subarachnoid hemorrhage (SAH, a physiologic stress response is triggered. This includes activation of the hypothalamic-pituitary-adrenal (HPA axis and the sympathetic nervous system. The aim of this study was to investigate the very early responses of these systems.A porcine animal model of aneurysmal SAH was used. In this model, blood is injected slowly to the basal cisterns above the anterior skull base until the cerebral perfusion pressure is 0 mm Hg. Sampling was done from blood and urine at -10, +15, +75 and +135 minutes from time of induction of SAH. Analyses of adrenocorticotropic hormone (ACTH, cortisol, aldosterone, catecholamines and chromogranin-A were performed.Plasma ACTH, serum cortisol and plasma aldosterone increased in the samples following induction of SAH, and started to decline after 75 minutes. Urine cortisol also increased after SAH. Urine catecholamines and their metabolites were found to increase after SAH. Many samples were however below detection level, not allowing for statistical analysis. Plasma chromogranin-A peaked at 15 minutes after SAH, and thereafter decreased.The endocrine stress response after aneurysmal SAH was found to start within 15 minutes in the HPA axis with early peak values of ACTH, cortisol and aldosterone. The fact that the concentrations of the HPA axis hormones decreased 135 minutes after SAH may suggest that a similar pattern exists in SAH patients, thus making it difficult to catch these early peak values. There were also indications of early activation of the sympathetic nervous system, but the small number of valid samples made interpretation difficult.

  13. Automated segmentation and quantification of actin stress fibres undergoing experimentally induced changes.

    Science.gov (United States)

    Rogge, H; Artelt, N; Endlich, N; Endlich, K

    2017-11-01

    The actin cytoskeleton is a main component of cells and it is crucially involved in many physiological processes, e.g. cell motility. Changes in the actin organization can be effected by diseases or vice versa. Due to the nonuniform pattern, it is difficult to quantify reasonable features of the actin cytoskeleton for a significantly high cell number. Here, we present an approach capable to fully segment and analyse the actin cytoskeleton of 2D fluorescence microscopic images with a special focus on stress fibres. The extracted feature data include length, width, orientation and intensity distributions of all traced stress fibres. Our approach combines morphological image processing techniques and a trace algorithm in an iterative manner, classifying the segmentation result with respect to the width of the stress fibres and in nonfibre-like actin. This approach enables us to capture experimentally induced processes like the condensation or the collapse of the actin cytoskeleton. We successfully applied the algorithm to F-actin images of cells that were treated with the actin polymerization inhibitor latrunculin A. Furthermore, we verified the robustness of our algorithm by a sensitivity analysis of the parameters, and we benchmarked our algorithm against established methods. In summary, we present a new approach to segment actin stress fibres over time to monitor condensation or collapse processes. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  14. Inflation of stressed cylindrical tubes: an experimental study

    Science.gov (United States)

    Guo, Zhiming; Wang, Shibin; Li, Linan; Ji, Hongwei; Wang, Zhiyong; Cai, Songbao

    2014-06-01

    The inflation of an initially stressed cylindrical shell provides a good illustration of the phenomenon of the initiation and propagation of an instability, which shares the same mathematical and mechanical features with a variety of other strain localization phenomena in engineering structures and materials. The high speed CCD camera and digital image processing system were used to measure the 3D shape of the inflated cylindrical tube. The localized bulge of a cylindrical tube with closed ends forms when the internal pressure reaches a critical value Pcr. As more air is filled into the tube, the pressure drops but the radius at the centre of the bulge will increase until it reaches a maximum value rmax. With continued inflation, the pressure stays at a constant value Pp. The purpose of this study is to investigate the critical and propagation pressures in the tubes and the profile outside when the shells under axial tension and internal pressure were inflating. We focus on the influence of the axial tension on the critical pressure. In this paper the problem is explored through experimental efforts. A series of experiments were conducted on commercially available natural rubber latex tubes involving different geometries and initial axial tensions, which were regarded as isotropic, homogeneous, incompressible and hyper-elastic materials.

  15. Integrated omics analyses of retrograde signaling mutant delineate interrelated stress-response strata.

    Science.gov (United States)

    Bjornson, Marta; Balcke, Gerd Ulrich; Xiao, Yanmei; de Souza, Amancio; Wang, Jin-Zheng; Zhabinskaya, Dina; Tagkopoulos, Ilias; Tissier, Alain; Dehesh, Katayoon

    2017-07-01

    To maintain homeostasis in the face of intrinsic and extrinsic insults, cells have evolved elaborate quality control networks to resolve damage at multiple levels. Interorganellar communication is a key requirement for this maintenance, however the underlying mechanisms of this communication have remained an enigma. Here we integrate the outcome of transcriptomic, proteomic, and metabolomics analyses of genotypes including ceh1, a mutant with constitutively elevated levels of both the stress-specific plastidial retrograde signaling metabolite methyl-erythritol cyclodiphosphate (MEcPP) and the defense hormone salicylic acid (SA), as well as the high MEcPP but SA deficient genotype ceh1/eds16, along with corresponding controls. Integration of multi-omic analyses enabled us to delineate the function of MEcPP from SA, and expose the compartmentalized role of this retrograde signaling metabolite in induction of distinct but interdependent signaling cascades instrumental in adaptive responses. Specifically, here we identify strata of MEcPP-sensitive stress-response cascades, among which we focus on selected pathways including organelle-specific regulation of jasmonate biosynthesis; simultaneous induction of synthesis and breakdown of SA; and MEcPP-mediated alteration of cellular redox status in particular glutathione redox balance. Collectively, these integrated multi-omic analyses provided a vehicle to gain an in-depth knowledge of genome-metabolism interactions, and to further probe the extent of these interactions and delineate their functional contributions. Through this approach we were able to pinpoint stress-mediated transcriptional and metabolic signatures and identify the downstream processes modulated by the independent or overlapping functions of MEcPP and SA in adaptive responses. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  16. Medical Standards for Experimental Human Use in Acceleration Stress Research

    Science.gov (United States)

    1983-01-01

    or re- teroposterior and lateral X-rays of the cervical, thoracic, sources, we consider a positive treadmill test to be dis- and lumbar spine. These...Gz stress. The requirement for a complete cervical, thoracic and dividuals who developed significant stress dysrhythmias lumbar spine X-ray series...hematoma h. Hernia Ill. Cardiac Stress: a. Dywrhythmla (Tachyarrhythmias and Bradyarrhythmim) b. Heart blocks c. Stress caadlomyopmt U244 Awono. spme

  17. Structural characterisation and transdermal delivery studies on sugar microneedles: experimental and finite element modelling analyses.

    Science.gov (United States)

    Loizidou, Eriketi Z; Williams, Nicholas A; Barrow, David A; Eaton, Mark J; McCrory, John; Evans, Sam L; Allender, Chris J

    2015-01-01

    Dissolving microneedles are especially attractive for transdermal drug delivery as they are associated with improved patient compliance and safety. Furthermore, microneedles made of sugars offer the added benefit of biomolecule stabilisation making them ideal candidates for delivering biological agents such as proteins, peptides and nucleic acids. In this study, we performed experimental and finite element analyses to study the mechanical properties of sugar microneedles and evaluate the effect of sugar composition on microneedle ability to penetrate and deliver drug to the skin. Results showed that microneedles made of carboxymethylcellulose/maltose are superior to those made of carboxymethylcellulose/trehalose and carboxymethylcellulose/sucrose in terms of mechanical strength and the ability to deliver drug. Buckling was predicted to be the main mode of microneedle failure and the order of buckling was positively correlated to the Young's modulus values of the sugar constituents of each microneedle. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Theoretical and experimental analyses of tunable Fabry-Perot resonators using piezoelectric phononic crystals.

    Science.gov (United States)

    Ponge, Marie-Fraise; Dubus, Bertrand; Granger, Christian; Vasseur, Jerome O; Thi, Mai Pham; Hladky-Hennion, Anne-Christine

    2015-06-01

    Theoretical and experimental analyses of piezoelectric stacks submitted to periodical electrical boundary conditions via electrodes are conducted. The presented structures exhibit Bragg band gaps that can be switched on or off by setting electrodes in short or open circuit. The band gap frequency width is determined by the electromechanical coupling coefficient. This property is used to design a Fabry-Perot cavity delimited by a periodic piezoelectric stack. An analytical model based on a transfer matrix formalism is used to model the wave propagation inside the structure. The cavity resonance tunability is obtained by varying the cavity length (i.e., by spatially shifting boundary conditions in the stack). 26% tuning of resonance and antiresonance frequencies with almost constant electromechanical coupling coefficient of 5% are theoretically predicted for an NCE41 resonator. To optimize the device, the influence of various parameters is theoretically investigated. The cavity length, phononic crystal (number and length of unit cells), and transducer position can be adapted to tune the frequency shift and the coupling coefficient. When the transducer is located at a nodal plane of the cavity, the value of the coupling coefficient is 30%. Experimental results are presented and discussed analyzing the effects of damping.

  19. Modeling of high homologous temperature deformation behavior for stress and life-time analyses

    Energy Technology Data Exchange (ETDEWEB)

    Krempl, E. [Rensselaer Polytechnic Institute, Troy, NY (United States)

    1997-12-31

    Stress and lifetime analyses need realistic and accurate constitutive models for the inelastic deformation behavior of engineering alloys at low and high temperatures. Conventional creep and plasticity models have fundamental difficulties in reproducing high homologous temperature behavior. To improve the modeling capabilities {open_quotes}unified{close_quotes} state variable theories were conceived. They consider all inelastic deformation rate-dependent and do not have separate repositories for creep and plasticity. The viscoplasticity theory based on overstress (VBO), one of the unified theories, is introduced and its properties are delineated. At high homologous temperature where secondary and tertiary creep are observed modeling is primarily accomplished by a static recovery term and a softening isotropic stress. At low temperatures creep is merely a manifestation of rate dependence. The primary creep modeled at low homologous temperature is due to the rate dependence of the flow law. The model is unaltered in the transition from low to high temperature except that the softening of the isotropic stress and the influence of the static recovery term increase with an increase of the temperature.

  20. Transcriptomic and physiological analyses of Medicago sativa L. roots in response to lead stress.

    Science.gov (United States)

    Xu, Bo; Wang, Yingzhe; Zhang, Shichao; Guo, Qiang; Jin, Yan; Chen, Jingjing; Gao, Yunhang; Ma, Hongxia

    2017-01-01

    Lead (Pb) is one of the nonessential and toxic metals that threaten the environment and human health. Medicago sativa L. is a legume with high salt tolerance and high biomass production. It is not only a globally important forage crop but is also an ideal plant for phytoremediation. However, the biological and molecular mechanisms that respond to heavy metals are still not well defined in M. sativa. In this study, de novo and strand-specific RNA-sequencing was performed to identify genes involved in the Pb stress response in M. sativa roots. A total of 415,350 unigenes were obtained from the assembled cDNA libraries, among which 5,416 were identified as significantly differentially expressed genes (DEGs) (false discovery rate < 0.005) between cDNA libraries from control and Pb-treated plants. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the DEGs showed they mainly clustered with terms associated with binding, transport, membranes, and the pathways related to signal and energy metabolism. Moreover, a number of candidate genes included antioxidant enzymes, metal transporters, and transcription factors involved in heavy metal response were upregulated under Pb stress. Quantitative real-time PCR(qRT-PCR) validation of the expression patterns of 10 randomly selected candidate DEGs were consistent with the transcriptome analysis results. Thus, this study offers new information towards the investigation of biological changes and molecular mechanisms related to Pb stress response in plants.

  1. Focal mechanism and stress analyses for main tectonic zones in Albania

    Science.gov (United States)

    Dushi, Edmond; Koçi, Rexhep; Begu, Enkela; Bozo, Rrezart

    2017-04-01

    In this study, a number of 33 moderate earthquakes for the period 2013-2015, ranging in magnitude within 2.2 ≤ MW ≤ 4.9 and located within the Albanian territory, have been analyzed. As an earthquake prone country, situated at the frontal collision boundary between Adria microplate and Eurasian tectonic plate, Albania is characterized frequently by micro earthquakes, many moderate and seldom by strong ones. It is evidenced that the whole territory is divided in two different tectonic domains, correspondingly the outer and the inner domain, showing different stress regime as clearly evidenced based on earthquake focal mechanism and geodetic studies. Although strong earthquakes are clearly related to faults in tectonically active areas, moderate events are more frequent revealing valuable information on this purpose. All the studied events are selected to be well-recorded by a maximum possible number of the local broadband (BB) seismological stations of Albanian Seismological Network (ASN), although regional stations have been used as well to constrain the solution. Earthquakes are grouped according to their location, within three well-defined tectonic zones, namely: Adriatic-Ionian (AI), Lushnja-Elbasani-Dibra (LED) and Ohrid-Korça (OK). For each event, the seismic moment M0is determined, through spectral analyses. Moment values vary ranging 1012 - 1015 Nm, for the Adriatic-Ionian (AI) outer zone; 1013 - 1016 Nm, for the Lushnja-Elbasani-Dibra (LED) transversal zone, which cuts through both the outer and the inner domains and 1012 - 1014 Nm, for the Ohrid-Korça (OK), north-south trending inner zone. Focal mechanism solutions (FMS) have been determined for each earthquake, based on the robust first motion polarities method, as applied in the FOCMEC (Seisan 10.1) routine. Using the Michael's linear bootstrap invertion on FMS, a stress analysis is applied. Results show the minimum compressional stress directions variation: σ1 370/270, σ23030/80 and σ31980

  2. Experimental investigation of stress wave propagation in standing trees

    Science.gov (United States)

    Houjiang Zhang; Xiping Wang; Juan Su

    2011-01-01

    The objective of this study was to investigate how a stress wave travels in a standing tree as it is introduced into the tree trunk through a mechanical impact. A series of stress wave time-of-flight (TOF) data were obtained from three freshly-cut red pine (Pinus resinosa Ait.) logs by means of a two-probe stress wave timer. Two-dimensional (2D) and three-dimensional (...

  3. The Effect of Calendula officinalis on Oxidative Stress and Bone Loss in Experimental Periodontitis

    Directory of Open Access Journals (Sweden)

    Mariana dos Reis Lima

    2017-06-01

    Full Text Available Periodontitis is associated with reduced antioxidant capacity and increased oxidative damage. Oxidative stress induces inflammation and bone loss contributing to the pathological progression of periodontal disease. Calendula officinalis (CLO has demonstrated anti-inflammatory and anti-oxidant activities. Therefore, the aim of this study was to evaluate the effect of CLO on oxidative stress and bone loss in rats subjected to experimental periodontitis (EP. For this, 72 male Wistar rats were divided into groups: Naïve, Saline (SAL and CLO. Rats received SAL or CLO (90 mg/kg 30 min before ligature and daily until the 11th day. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic analysis of alveolar bone loss (ABL. Periodontium was analyzed by macroscopy, scanning electron microscopy; confocal and light polarized microscopy. Immunohistochemical examination of DKK1, WNT 10b and β-catenin was performed. The gingival tissue was collected to reduced glutathione (GSH, superoxide dismutase (SOD, catalase (CAT and malondialdehyde (MDA analyses. The 11 days of ligature induced bone loss, breakdown of collagen fibers, increased the immunostaining DKK-1 while reduced WNT 10b and β-catenin expressions. Periodontitis reduced GSH, SOD, CAT and increase MDA. All findings were reversed by 90 mg/kg of CLO. In summary our findings demonstrated that CLO reduced oxidative stress and bone loss and preserved collagen fibers in rats with EP, with participation of WNT signaling pathway.

  4. The Effect ofCalendula officinalison Oxidative Stress and Bone Loss in Experimental Periodontitis.

    Science.gov (United States)

    Lima, Mariana Dos Reis; Lopes, Amanda P; Martins, Conceição; Brito, Gerly A C; Carneiro, Virgínia C; Goes, Paula

    2017-01-01

    Periodontitis is associated with reduced antioxidant capacity and increased oxidative damage. Oxidative stress induces inflammation and bone loss contributing to the pathological progression of periodontal disease. Calendula officinalis (CLO) has demonstrated anti-inflammatory and anti-oxidant activities. Therefore, the aim of this study was to evaluate the effect of CLO on oxidative stress and bone loss in rats subjected to experimental periodontitis (EP). For this, 72 male Wistar rats were divided into groups: Naïve, Saline (SAL) and CLO. Rats received SAL or CLO (90 mg/kg) 30 min before ligature and daily until the 11th day. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic analysis of alveolar bone loss (ABL). Periodontium was analyzed by macroscopy, scanning electron microscopy; confocal and light polarized microscopy. Immunohistochemical examination of DKK1, WNT 10b and β-catenin was performed. The gingival tissue was collected to reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) analyses. The 11 days of ligature induced bone loss, breakdown of collagen fibers, increased the immunostaining DKK-1 while reduced WNT 10b and β-catenin expressions. Periodontitis reduced GSH, SOD, CAT and increase MDA. All findings were reversed by 90 mg/kg of CLO. In summary our findings demonstrated that CLO reduced oxidative stress and bone loss and preserved collagen fibers in rats with EP, with participation of WNT signaling pathway.

  5. The Effect of Calendula officinalis on Oxidative Stress and Bone Loss in Experimental Periodontitis

    Science.gov (United States)

    Lima, Mariana dos Reis; Lopes, Amanda P.; Martins, Conceição; Brito, Gerly A. C.; Carneiro, Virgínia C.; Goes, Paula

    2017-01-01

    Periodontitis is associated with reduced antioxidant capacity and increased oxidative damage. Oxidative stress induces inflammation and bone loss contributing to the pathological progression of periodontal disease. Calendula officinalis (CLO) has demonstrated anti-inflammatory and anti-oxidant activities. Therefore, the aim of this study was to evaluate the effect of CLO on oxidative stress and bone loss in rats subjected to experimental periodontitis (EP). For this, 72 male Wistar rats were divided into groups: Naïve, Saline (SAL) and CLO. Rats received SAL or CLO (90 mg/kg) 30 min before ligature and daily until the 11th day. Naïve group experienced no manipulation. After 11 days, the animals were euthanized and left maxillae collected for macroscopic analysis of alveolar bone loss (ABL). Periodontium was analyzed by macroscopy, scanning electron microscopy; confocal and light polarized microscopy. Immunohistochemical examination of DKK1, WNT 10b and β-catenin was performed. The gingival tissue was collected to reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) analyses. The 11 days of ligature induced bone loss, breakdown of collagen fibers, increased the immunostaining DKK-1 while reduced WNT 10b and β-catenin expressions. Periodontitis reduced GSH, SOD, CAT and increase MDA. All findings were reversed by 90 mg/kg of CLO. In summary our findings demonstrated that CLO reduced oxidative stress and bone loss and preserved collagen fibers in rats with EP, with participation of WNT signaling pathway. PMID:28701962

  6. Modeling and stress analyses of a normal foot-ankle and a prosthetic foot-ankle complex.

    Science.gov (United States)

    Ozen, Mustafa; Sayman, Onur; Havitcioglu, Hasan

    2013-01-01

    Total ankle replacement (TAR) is a relatively new concept and is becoming more popular for treatment of ankle arthritis and fractures. Because of the high costs and difficulties of experimental studies, the developments of TAR prostheses are progressing very slowly. For this reason, the medical imaging techniques such as CT, and MR have become more and more useful. The finite element method (FEM) is a widely used technique to estimate the mechanical behaviors of materials and structures in engineering applications. FEM has also been increasingly applied to biomechanical analyses of human bones, tissues and organs, thanks to the development of both the computing capabilities and the medical imaging techniques. 3-D finite element models of the human foot and ankle from reconstruction of MR and CT images have been investigated by some authors. In this study, data of geometries (used in modeling) of a normal and a prosthetic foot and ankle were obtained from a 3D reconstruction of CT images. The segmentation software, MIMICS was used to generate the 3D images of the bony structures, soft tissues and components of prosthesis of normal and prosthetic ankle-foot complex. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones, soft tissues and components of prosthesis were independently developed to form foot and ankle complex. SOLIDWORKS program was used to form the boundary surfaces of all model components and then the solid models were obtained from these boundary surfaces. Finite element analyses software, ABAQUS was used to perform the numerical stress analyses of these models for balanced standing position. Plantar pressure and von Mises stress distributions of the normal and prosthetic ankles were compared with each other. There was a peak pressure increase at the 4th metatarsal, first metatarsal and talus bones and a decrease at the intermediate cuneiform and calcaneus bones, in

  7. Development of Endoplasmic Reticulum Stress during Experimental Oxalate Nephrolithiasis.

    Science.gov (United States)

    Motin, Yu G; Lepilov, A V; Bgatova, N P; Zharikov, A Yu; Motina, N V; Lapii, G A; Lushnikova, E L; Nepomnyashchikh, L M

    2016-01-01

    Morphological and ultrastructural study of the kidney was performed in rats with oxalate nephrolithiasis. Specific features of endoplasmic reticulum stress were evaluated during nephrolithiasis and treatment with α-tocopherol. We observed the signs of endoplasmic reticulum stress with activation of proapoptotic pathways and injury to the cell lining in nephron tubules and collecting ducts. Ultrastructural changes were found in the organelles, nuclei, and cell membranes of epitheliocytes. A relationship was revealed between endoplasmic reticulum stress and oxidative damage, which developed at the early state of lithogenesis.

  8. A protocol for analysing thermal stress in insects using infrared thermography.

    Science.gov (United States)

    Gallego, Belén; Verdú, José R; Carrascal, Luis M; Lobo, Jorge M

    2016-02-01

    The study of insect responses to thermal stress has involved a variety of protocols and methodologies that hamper the ability to compare results between studies. For that reason, the development of a protocol to standardize thermal assays is necessary. In this sense, infrared thermography solves some of the problems allowing us to take continuous temperature measurements without handling the individuals, an important fact in cold-blooded organisms like insects. Here, we present a working protocol based on infrared thermography to estimate both cold and heat thermal stress in insects. We analyse both the change in the body temperature of individuals and their behavioural response. In addition, we used partial least squares regression for the statistical analysis of our data, a technique that solves the problem of having a large number of variables and few individuals, allowing us to work with rare or endemic species. To test our protocol, we chose two species of congeneric, narrowly distributed dung beetles that are endemic to the southeastern part of the Iberian Peninsula. With our protocol we have obtained five variables in the response to cold and twelve in the response to heat. With this methodology we discriminate between the two flightless species of Jekelius through their thermal response. In response to cold, Jekelius hernandezi showed a higher rate of cooling and reached higher temperatures of stupor and haemolymph freezing than Jekelius punctatolineatus. Both species displayed similar thermoregulation ranges before reaching lethal body temperature with heat stress. Overall, we have demonstrated that infrared thermography is a suitable method to assess insect thermal responses with a high degree of sensitivity, allowing for the discrimination between closely related species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Geophagy (rock eating, experimental stress and cognitive idiosyncrasy

    Directory of Open Access Journals (Sweden)

    Kirill Golokhvast

    2014-05-01

    Conclusions: These results suggest that, in natural environmental conditions, “edible” rocks serve as an adaptive tool for recovery from various types of environmental stresses, and are examples of self-medication.

  10. Calligraphy and meditation for stress reduction: an experimental comparison

    Directory of Open Access Journals (Sweden)

    Kao H SR

    2014-02-01

    Full Text Available Henry SR Kao,1 Lin Zhu,2 An An Chao,3 Hao Yi Chen,4 Ivy CY Liu,5 Manlin Zhang6 1Department of Social Work and Social Administration, University of Hong Kong, Hong Kong; 2Department of Psychology, Renmin University of China, Beijing, 3International Society of Calligraphy Therapy, Hong Kong; 4Department of Business Administration, National Chengchi University, Taipei, Taiwan, 5Department of Psychology, Fu Jen Catholic University, Taipei, Taiwan; 6Department of Psychology, Sun Yat-Sen University, Guangzhou, People's Republic of China Background: Chinese calligraphic handwriting (CCH has demonstrated a new role in health and therapy. Meanwhile, meditation is an traditional and effective method for coping with stress and staying healthy. This study compared the effectiveness of CCH and meditation as distinctive and parallel stress reduction interventions. Methods: Thirty graduate students and academic staff members in Taiwan who suffered from stress were selected by the General Health Questionnaire and randomly assigned to one of three treatment groups, ie, a CCH group, a meditation group, or a control group, for 8 consecutive weeks. Changes in physiological parameters were measured before, during, and after treatment. Results: CCH and meditation showed their strength in the respective indices of stress. There was a significant difference in respiratory rate, heart rate, and electromyographic scores between the groups. Comparing pre- and post-effects, a decrease in heart rate and an increase in skin temperature was seen in subjects who practiced CCH. Increased skin temperature and decreased respiratory rate were also seen in subjects who practiced meditation, along with reduced muscle tension and heart rate. Conclusion: CCH and meditation have good effects in stress reduction. CCH is a particularly promising new approach to reducing stress.Keywords: calligraphic handwriting, meditation, stress reduction, intervention

  11. Reproductive effort affects oxidative status and stress in an Antarctic penguin species: An experimental study.

    Directory of Open Access Journals (Sweden)

    Roger Colominas-Ciuró

    Full Text Available The oxidative cost of reproduction has been a matter of debate in recent years presumably because of the lack of proper experimental studies. Based on the hypothesis that different brood sizes produce differential reproductive costs, an experimental manipulation during breeding of Adélie penguins was conducted at Hope Bay, Antarctica, to study oxidative status and stress. We predict that a lower reproductive effort should be positively related to low oxidative and physiological stress. We randomly assigned nests with two chicks to a control reproductive effort group (CRE, and by removing one chick from some nests with two chicks, formed a second, low reproductive effort group (LRE. We examined how oxidative status in blood plasma (reactive oxygen metabolites, ROMs, and total antioxidant capacity, OXY and stress (heterophil/lymphocyte ratio, H/L responded to a lower production of offspring total biomass. Our nest manipulation showed significant differences in offspring total biomass, which was lower in the LRE group. As predicted, the LRE group had higher antioxidant capacity than individuals in the CRE group. We have also found, although marginally significant, interactions between sex and treatment in the three variables analysed. Females had higher OXY, lower ROMs and lower H/L ratio when rearing one chick, whereas males did so when rearing two except for OXY which was high regardless of treatment. Moreover, there was a significant negative correlation between the H/L ratio and OXY in females. Finally, we have found a negative and significant relationship between the duration of the experiment and OXY and ROMs and positive with H/L ratio which suggests that indeed breeding penguins are paying an effort in physiological terms in relation to the duration of the chick rearing. In conclusion, a reduction of the reproductive effort decreased oxidative stress in this long-lived bird meaning that a link exists between breeding effort and oxidative

  12. Reproductive effort affects oxidative status and stress in an Antarctic penguin species: An experimental study.

    Science.gov (United States)

    Colominas-Ciuró, Roger; Santos, Mercedes; Coria, Néstor; Barbosa, Andrés

    2017-01-01

    The oxidative cost of reproduction has been a matter of debate in recent years presumably because of the lack of proper experimental studies. Based on the hypothesis that different brood sizes produce differential reproductive costs, an experimental manipulation during breeding of Adélie penguins was conducted at Hope Bay, Antarctica, to study oxidative status and stress. We predict that a lower reproductive effort should be positively related to low oxidative and physiological stress. We randomly assigned nests with two chicks to a control reproductive effort group (CRE), and by removing one chick from some nests with two chicks, formed a second, low reproductive effort group (LRE). We examined how oxidative status in blood plasma (reactive oxygen metabolites, ROMs, and total antioxidant capacity, OXY) and stress (heterophil/lymphocyte ratio, H/L) responded to a lower production of offspring total biomass. Our nest manipulation showed significant differences in offspring total biomass, which was lower in the LRE group. As predicted, the LRE group had higher antioxidant capacity than individuals in the CRE group. We have also found, although marginally significant, interactions between sex and treatment in the three variables analysed. Females had higher OXY, lower ROMs and lower H/L ratio when rearing one chick, whereas males did so when rearing two except for OXY which was high regardless of treatment. Moreover, there was a significant negative correlation between the H/L ratio and OXY in females. Finally, we have found a negative and significant relationship between the duration of the experiment and OXY and ROMs and positive with H/L ratio which suggests that indeed breeding penguins are paying an effort in physiological terms in relation to the duration of the chick rearing. In conclusion, a reduction of the reproductive effort decreased oxidative stress in this long-lived bird meaning that a link exists between breeding effort and oxidative stress. However

  13. Artificial Warming of Arctic Meadow under Pollution Stress: Experimental design

    Science.gov (United States)

    Moni, Christophe; Silvennoinen, Hanna; Fjelldal, Erling; Brenden, Marius; Kimball, Bruce; Rasse, Daniel

    2014-05-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, notably because future warming is expected to be disproportionate as compared to world averages. Likewise, greenhouse gas (GHG) release from terrestrial ecosystems exposed to climate warming is expected to be the largest in the arctic. Artic agriculture, in the form of cultivated grasslands, is a unique and economically relevant feature of Northern Norway (e.g. Finnmark Province). In Eastern Finnmark, these agro-ecosystems are under the additional stressor of heavy metal and sulfur pollution generated by metal smelters of NW Russia. Warming and its interaction with heavy metal dynamics will influence meadow productivity, species composition and GHG emissions, as mediated by responses of soil microbial communities. Adaptation and mitigation measurements will be needed. Biochar application, which immobilizes heavy metal, is a promising adaptation method to promote positive growth response in arctic meadows exposed to a warming climate. In the MeadoWarm project we conduct an ecosystem warming experiment combined to biochar adaptation treatments in the heavy-metal polluted meadows of Eastern Finnmark. In summary, the general objective of this study is twofold: 1) to determine the response of arctic agricultural ecosystems under environmental stress to increased temperatures, both in terms of plant growth, soil organisms and GHG emissions, and 2) to determine if biochar application can serve as a positive adaptation (plant growth) and mitigation (GHG emission) strategy for these ecosystems under warming conditions. Here, we present the experimental site and the designed open-field warming facility. The selected site is an arctic meadow located at the Svanhovd Research station less than 10km west from the Russian mining city of Nikel. A splitplot design with 5 replicates for each treatment is used to test the effect of biochar amendment and a 3oC warming on the Arctic meadow. Ten circular

  14. Experimental Tooling for Contact Stress Measurement in Bulk Metal Forming Processes

    Science.gov (United States)

    Vilotić, Dragiša; Plančak, Miroslav

    2011-01-01

    Knowledge of contact stresses in metal forming operations is essential not only for optimal die design, but also for theoretical and numerical analysis of the metal forming processes. Determination of contact stresses can be performed theoretically and experimentally. This paper presents a tool construction with built-in pin-load cells for experimental determination of contact stresses and friction coefficient at upsetting of prismatic specimen with cylindrical dies. This construction allows measurement of contact stresses in any point of the contact surface of specimen, due to adjustable location of pin-load cells. The adjustments are performed by turning cylindrical dies around its own axis in combination with the change of axial position of the specimen. Experimental determination of contact stresses in upsetting of Ck35 prismatic specimens using cylindrical tools was performed at the Laboratory for technology of plasticity, FTN Novi Sad.

  15. Interferon-gamma regulates oxidative stress during experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Espejo, Carmen; Penkowa, Milena; Sáez-Torres, Irene

    2002-01-01

    disease eliciting secretion of proinflammatory cytokines like IFN-gamma or TNF-alpha, and it has been suggested that cytokine-induced oxidative stress could have a role in EAE neuropathology. However, the individual roles of these and other cytokines in the pathogenesis of the disease are still uncertain....... Here we analyze the role of IFN-gamma during EAE by using both IFN-gamma receptor-knockout (IFN-gamma R(-/-)) and wild-type mice, both strains immunized with peptide 40-55 from rat myelin oligodendrocyte glycoprotein. The levels of oxidative stress were determined through the analysis...... of immunoreactivity for inducible NO synthase, nitrotyrosine, and malondialdehyde, as well as through the expression of the tissue-protective antioxidant factors metallothionein I+II (MT-I+II). We also examined the number of cells undergoing apoptosis as judged by using the TUNEL technique. The levels of oxidative...

  16. Experimental Hepatic Carcinogenesis: Oxidative Stress and Natural Antioxidants

    Directory of Open Access Journals (Sweden)

    Velid Unsal

    2017-08-01

    Full Text Available Hepatocellular carcinoma is one of the most common cancers in the world, and it is influenced by agents such as DEN, 2-AAF, phenobarbital, alcohol, aflatoxin B1 metabolite or hepatitis viruses (B and C. Oxidative stress is becoming recognized as a key factor in the progression of hepatocarcinogenesis. Reactive oxygen species can play a leading role in initiation and promotion of hepatic carcinogenesis. The metabolites of DEN Diethylnitrosamine (DEN mediate the binding of tumour promoters by covalently binding to the DNA with one or two oxidation-providing electrons. 2-AAF is the inducer of DEN, and it is involved in tumour formation in the bladder and liver. Reactive Oxygen species (ROS; carbohydrates, lipids, DNA and enzymes, such as affect all important structures. Additionally, an excessive amount of ROS is highly toxic to cells. Antioxidants are protects against ROS, toxic substances, carcinogens. This review focuses on the literature on studies of Hepatic Carcinogenesis, oxidative stress and antioxidant therapy.

  17. Experimental Evidence for Nutrition Regulated Stress Resistance in Drosophila ananassae

    OpenAIRE

    Seema Sisodia; Singh, Bashisth N.

    2012-01-01

    BACKGROUND: The amount and quality of nutrients consumed by organisms have a strong impact on stress resistance, life-history traits and reproduction. The balance between energy acquisition and expenditure is crucial to the survival and reproductive success of animals. The ability of organisms to adjust their development, physiology or behavior in response to environmental conditions, called phenotypic plasticity, is a defining property of life. One of the most familiar and important examples...

  18. Experimental evidence for nutrition regulated stress resistance in Drosophila ananassae.

    Directory of Open Access Journals (Sweden)

    Seema Sisodia

    Full Text Available BACKGROUND: The amount and quality of nutrients consumed by organisms have a strong impact on stress resistance, life-history traits and reproduction. The balance between energy acquisition and expenditure is crucial to the survival and reproductive success of animals. The ability of organisms to adjust their development, physiology or behavior in response to environmental conditions, called phenotypic plasticity, is a defining property of life. One of the most familiar and important examples of phenotypic plasticity is the response of stress tolerance and reproduction to changes in developmental nutrition. Larval nutrition may affect a range of different life-history traits as well as responses to environmental stress in adult. PRINCIPAL FINDINGS: Here we investigate the effect of larval nutrition on desiccation, starvation, chill-coma recovery, heat resistance as well as egg to adult viability, egg production and ovariole number in Drosophila ananassae. We raised larvae on either protein rich diet or carbohydrate rich diet. We found that flies consuming protein rich diet have higher desiccation and heat shock resistance whereas flies developed on carbohydrate rich diet have higher starvation and cold resistance. Egg production was higher in females developed on protein rich diet and we also found trade-off between egg production and Egg to adult viability of the flies. Viability was higher in carbohydrate rich diet. However, sex specific viability was found in different nutritional regimes. Higher Egg production might be due to higher ovariole number in females of protein rich diet. CONCLUSION: Thus, Drosophila ananassae adapts different stress tolerance and life-history strategies according to the quality of the available diet, which are correlated with phenotypic adjustment at anatomical and physiological levels.

  19. Metabolomic analyses to evaluate the effect of drought stress on selected African Eggplant accessions.

    Science.gov (United States)

    Mibei, Elias K; Owino, Willis O; Ambuko, Jane; Giovannoni, James J; Onyango, Arnold N

    2018-01-01

    Drought stress is one of the main abiotic stresses that affect crops. It leads to biochemical changes that can have adverse effects on plant growth, development and productivity. African eggplants are important vegetable and fruit crops reported to adapt and thrive well under drought stress. The diversified metabolites arising due to stress have not been well defined. A gas chromatographic-mass spectrometric metabolomic approach was applied to characterize the effect of drought stress on metabolites at different stages of growth. Nineteen accessions were selected for analysis and drought was imposed by withholding water until soil moisture reached 60% field capacity. Fresh leaf tissues were sampled before stress, 2 and 4 weeks after stress and metabolite profiling done. Significant changes in metabolite content were observed, and potentially important metabolites with respect to stress responses were characterized. Proline, glutamate, sucrose, fructose and tricarboxylic acid cycle metabolites were shown to be positively correlated with stress. Principal component analysis showed a clear discrimination between the different accessions, growth stages and stress/control conditions. The results illustrate that drought stress has a significant impact on the concentrations of some metabolites, such as amino acids, sugars and organic acids, which may contribute to drought stress effects and tolerance. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Theoretical and experimental estimates of the Peierls stress

    CSIR Research Space (South Africa)

    Nabarro, FRN

    1997-03-01

    Full Text Available an error of a factor of 2 in this exponent in Peierls's original estimate. A revised estimate by Huntington introduced a further factor of 2. Three experimental estimates are available, from the Bordoni peaks (which agrees with the Huntington theory), from...

  1. Experimental and modeling analyses for interactions between graphene oxide and quartz sand.

    Science.gov (United States)

    Kang, Jin-Kyu; Park, Jeong-Ann; Yi, In-Geol; Kim, Song-Bae

    2017-03-21

    The aim of this study was to quantify the interactions between graphene oxide (GO) and quartz sand by conducting experimental and modeling analyses. The results show that both GO and quartz sand were negatively charged in the presence of 0-50 mM NaCl and 5 mM CaCl 2 (GO = -43.10 to -17.60 mV, quartz sand = -40.97 to -8.44 mV). In the Derjaguin-Landau-Verwey-Overbeek (DLVO) energy profiles, the adhesion of GO to quartz sand becomes more favorable with increasing NaCl concentration from 0 to 10 mM because the interaction energy profile was compressed and the primary maximum energy barrier was lowered. At 50 mM NaCl and 5 mM CaCl 2 , the primary maximum energy barrier even disappeared, resulting in highly favorable conditions for GO retention to quartz sand. In the Maxwell model analysis, the probability of GO adhesion to quartz sand (α m ) increased from 2.46 × 10 -4 to 9.98 × 10 -1 at ionic strengths of 0-10 mM NaCl. In the column experiments (column length = 10 cm, inner diameter = 2.5 cm, flow rate = 0.5 mL min -1 ), the mass removal (Mr) of GO in quartz sand increased from 5.4% to 97.8% as the NaCl concentration was increased from 0 to 50 mM, indicating that the mobility of GO was high in low ionic strength solutions and decreased with increasing ionic strength. The Mr value of GO at 5 mM CaCl 2 was 100%, demonstrating that Ca 2+ had a much stronger effect than Na + on the mobility of GO. In addition, the mobility of GO was lower than that of chloride (Mr = 1.4%) but far higher than that of multi-walled carbon nanotubes (Mr = 87.0%) in deionized water. In aluminum oxide-coated sand, the Mr value of GO was 98.1% at 0 mM NaCl, revealing that the mobility of GO was reduced in the presence of metal oxides. The transport model analysis indicates that the value of the dimensionless attachment rate coefficient (D a ) increased from 0.11 to 4.47 as the NaCl concentration was increased from 0 to 50 mM. In the colloid filtration model analysis, the

  2. Effect of Reinforcement on Early-Age Concrete Temperature Stress: Preliminary Experimental Investigation and Analytical Simulation

    Directory of Open Access Journals (Sweden)

    Jianda Xin

    2015-01-01

    Full Text Available For concrete under short-term loading, effect of reinforcement on concrete crack resistance capability is usually negligible; however, recent research results show that extension of this viewpoint to concrete under long-term loading (temperature variation may be unsuitable. In order to investigate this phenomenon, this paper presents the experimental and analytical results of early-age reinforced concrete temperature stress development under uniaxial restraint. The experiments were carried out on a temperature stress testing machine (TSTM. Experimental results show that the coupling of reinforcement and concrete creep behavior influenced the concrete temperature stress development, and nearly 16% of concrete stress was reduced in the current research. Moreover, the cracking time of reinforced concrete was also delayed. Finally, based on the principle of superposition, analytical simulations of effect of reinforcement on concrete temperature stress have been performed.

  3. Interfacial stresses in vibration of multilayer composite materials: experimental and theoretical analysis

    Science.gov (United States)

    Agbossou, Amen; Barthod, Christine; Teisseyre, Yves; Gautier, Gérard

    2005-12-01

    In laminated composites, interfaces are the transfer spots of mechanical charges, mechanical over-stress adaptations and energy dissipations. In order to examine the dynamic effects of interface stresses, we have inserted a thin layer of piezoelectric material at the interface of composite plies of a multilayer cantilever beam excited in bending. The voltage signals generated by the piezoelectric elements are seen to be dependent on the expected interlaminar stresses. Moreover, the realized experimental set-up validates the parameters of finite element simulations. Using the implemented finite element model, two different piezoelectric materials are compared with regard to their possibility for interfacial stress measurement and for mechanical energy dissipation.

  4. Coping with examination stress through hypnosis: an experimental study.

    Science.gov (United States)

    Palan, B M; Chandwani, S

    1989-01-01

    Fifty-six volunteer medical students participated in three groups balanced for number of subjects, performance at last examination, and hypnotizability. The hypnosis and waking groups attended eight group sessions once a week with general ego-strengthening and specific suggestions for study habits, with a ninth session of age progression and mental rehearsal. Subjects in these two groups practiced self-suggestions (in self-hypnosis or waking respectively) daily for the study period of 9 weeks. The control group experienced sessions of passive relaxation induced by light reading for the same period of time. The hypnosis group improved significantly in coping with examination stress, but there was no significant change in performance on examinations by any of the groups.

  5. Experimental and Numerical Studies on Residual Stress in Wide Butt Welds

    Directory of Open Access Journals (Sweden)

    Yang Ding

    2017-01-01

    Full Text Available The presence of residual stress in steel members can significantly compromise the stiffness and fatigue life of steel structural components. This influence becomes more serious for the wide butt welds in the construction of large-sized steel members due to the different residual stress distribution from the normal size butt welds. This paper experimentally studied the residual stress in the wide butt welds through an 8-experiment test program. High residual stress was produced during the wide butt welding and this stress was observed to be even higher than the yield strength of the steel. Moreover, this residual stress in the steel plate was firstly compressive and then transferred into tensile stress with the increase in the distance away from the butt weld line. The magnitude of the residual stress increased with the increase in the width of the welding seams. This paper also developed a finite element model by SYSWELD to simulate the residual stress produced by the wide butt welding. The accuracy of the FE simulation was checked by the reported test results. In order to reduce the residual stress, the ultrasonic peening method was adopted. The analysis results indicated that ultrasonic peening method effectively reduced the residual stress caused by the wide butt welding during the construction.

  6. Oxidative Stress and Pulmonary Changes in Experimental Liver Cirrhosis

    Directory of Open Access Journals (Sweden)

    Renata Salatti Ferrari

    2012-01-01

    Full Text Available The use of carbon tetrachloride (CCl4 in rats is an experimental model of hepatic tissue damage; which leads to fibrosis, and at the long term, cirrhosis. Cirrhosis is the consequence of progressive continued liver damage, it may be reversible when the damaging noxae have been withdrawn. The aim of this study is to evaluate the changes caused by cirrhosis in lung and liver, through the experimental model of intraperitoneal CCI4 administration. We used 18 male Wistar rats divided into three groups: control (CO and two groups divided by the time of cirrhosis induction by CCI4: G1 (11 weeks, G2 (16 weeks. We found significant increase of transaminase levels and lipid peroxidation (TBARS in liver and lung tissue and also increased antioxidant enzymes SOD and CAT, as well as the expression of TNF-α and IL-1β in the lung of cirrhotic animals. We observed changes in gas exchange in both cirrhotic groups. We can conclude that our model reproduces a model of liver cirrhosis, which causes alterations in the pulmonary system that leads to changes in gas exchange and size of pulmonary vessels.

  7. End-systolic stress-velocity relation and circumferential fiber velocity shortening for analysing left ventricular function in mice

    Energy Technology Data Exchange (ETDEWEB)

    Fayssoil, A. [Cardiologie, Hopital europeen Georges Pompidou, 20, rue le blanc, Paris (France)], E-mail: fayssoil2000@yahoo.fr; Renault, G. [CNRS UMR 8104, Inserm, U567, Institut Cochin, Universite Paris Descartes, Paris (France); Fougerousse, F. [Genethon, RD, Evry (France)

    2009-08-15

    Traditionally, analysing left ventricular (LV) performance relies on echocardiography by evaluating shortening fraction (SF) in mice. SF is influenced by load conditions. End-systolic stress-velocity (ESSV) relation and circumferential fiber velocity (VcF) shortening are more relevant parameters for evaluating systolic function regardless load conditions particularly in mice's models of heart failure.

  8. Stress analyses for reactor pressure vessels by the example of a product line '69 boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mkrtchyan, Lilit; Schau, Henry [TUEV SUED Energietechnik GmbH, Mannheim (Germany). Abt. Strukturverhalten; Wolf, Werner; Holzer, Wieland [TUEV SUED Industrie Service GmbH, Muenchen (Germany). Abt. Behaelter und Turbosatz; Wernicke, Robert; Trieglaff, Ralf [TUEV NORD SysTec GmbH und Co. KG, Hamburg (Germany). Abt. Festigkeit und Konstruktion

    2011-08-15

    The reactor pressure vessels (RPV) of boiling water reactors (BWR) belonging to the product line '69 have unusually designed heads. The spherical cap-shaped bottom head of the vessel is welded directly to the support flange of the lower shell course. This unusual construction has led repeatedly to controversial discussions concerning the limits and admissibility of stress intensities arising in the junction of the bottom head to the cylindrical shell. In the present paper, stress analyses for the design conditions are performed with the finite element method in order to determine and categorize the occurring stresses. The procedure of stress classification in accordance with the guidelines of German KTA 3201.2 and Section III of the ASME Code (Subsection NB) is described and subsequently demonstrated by the example of a typical BWR vessel. The accomplished investigations yield allowable stress intensities in the considered area. Additionally, limit load analyses are carried out to verify the obtained results. Complementary studies, performed for a torispherical head, prove that the determined maximum peak stresses in the junction between the bottom head and the cylindrical shell are not unusual also for pressure vessels with regular bottom head constructions. (orig.)

  9. Transcriptome analyses reveal genotype- and developmental stage-specific molecular responses to drought and salinity stresses in chickpea.

    Science.gov (United States)

    Garg, Rohini; Shankar, Rama; Thakkar, Bijal; Kudapa, Himabindu; Krishnamurthy, Lakshmanan; Mantri, Nitin; Varshney, Rajeev K; Bhatia, Sabhyata; Jain, Mukesh

    2016-01-13

    Drought and salinity are the major factors that limit chickpea production worldwide. We performed whole transcriptome analyses of chickpea genotypes to investigate the molecular basis of drought and salinity stress response/adaptation. Phenotypic analyses confirmed the contrasting responses of the chickpea genotypes to drought or salinity stress. RNA-seq of the roots of drought and salinity related genotypes was carried out under control and stress conditions at vegetative and/or reproductive stages. Comparative analysis of the transcriptomes revealed divergent gene expression in the chickpea genotypes at different developmental stages. We identified a total of 4954 and 5545 genes exclusively regulated in drought-tolerant and salinity-tolerant genotypes, respectively. A significant fraction (~47%) of the transcription factor encoding genes showed differential expression under stress. The key enzymes involved in metabolic pathways, such as carbohydrate metabolism, photosynthesis, lipid metabolism, generation of precursor metabolites/energy, protein modification, redox homeostasis and cell wall component biogenesis, were affected by drought and/or salinity stresses. Interestingly, transcript isoforms showed expression specificity across the chickpea genotypes and/or developmental stages as illustrated by the AP2-EREBP family members. Our findings provide insights into the transcriptome dynamics and components of regulatory network associated with drought and salinity stress responses in chickpea.

  10. Comparative Cognitive Task Analyses of Experimental Science and Instructional Laboratory Courses

    Science.gov (United States)

    Wieman, Carl

    2015-01-01

    Undergraduate instructional labs in physics generate intense opinions. Their advocates are passionate as to their importance for teaching physics as an experimental activity and providing "hands-on" learning experiences, while their detractors (often but not entirely students) offer harsh criticisms that they are pointless, confusing and…

  11. Use of Brief Experimental Analyses in Outpatient Clinic and Home Settings

    Science.gov (United States)

    Wacker, David; Berg, Wendy; Harding, Jay; Cooper-Brown, Linda

    2004-01-01

    We describe the historic and current use of brief experimental analysis procedures in outpatient clinic and home settings. We discuss some applications of the designs and suggest design modifications for improving internal validity. We describe our application of the designs to longitudinal, in-home programs for children with severe behavior…

  12. Experimental investigation of the acoustic anisotropy field in the sample with a stress concentrator

    Directory of Open Access Journals (Sweden)

    Aleksey I. Grishchenko

    2017-03-01

    Full Text Available The behavior of acoustic anisotropy and the longitudinal wave velocity in the case of multiaxial stress-strain state of the plate under inelastic deformation has been studied experimentally. The plate had a stress concentrator in the form of the central hole. The results for several deformation levels, and the results of finite element analysis of active stresses were presented. The qualitative agreement between the calculated stress fields and the distribution fields of acoustic anisotropy was revealed. It was found that the absolute magnitude maximum of acoustic anisotropy fell on the areas with the biggest stresses near the concentrator. It was supposed that the non-uniform distribution of acoustic anisotropy in the material testified to a possible stress concentration at the corresponding points.

  13. Experimental and Computational Modal Analyses for Launch Vehicle Models considering Liquid Propellant and Flange Joints

    Directory of Open Access Journals (Sweden)

    Chang-Hoon Sim

    2018-01-01

    Full Text Available In this research, modal tests and analyses are performed for a simplified and scaled first-stage model of a space launch vehicle using liquid propellant. This study aims to establish finite element modeling techniques for computational modal analyses by considering the liquid propellant and flange joints of launch vehicles. The modal tests measure the natural frequencies and mode shapes in the first and second lateral bending modes. As the liquid filling ratio increases, the measured frequencies decrease. In addition, as the number of flange joints increases, the measured natural frequencies increase. Computational modal analyses using the finite element method are conducted. The liquid is modeled by the virtual mass method, and the flange joints are modeled using one-dimensional spring elements along with the node-to-node connection. Comparison of the modal test results and predicted natural frequencies shows good or moderate agreement. The correlation between the modal tests and analyses establishes finite element modeling techniques for modeling the liquid propellant and flange joints of space launch vehicles.

  14. Analyses of Deformation and Stress of Oil-free Scroll Compressor Scroll

    Science.gov (United States)

    Peng, Bin; Li, Yaohong; Zhao, Shenxian

    2017-12-01

    The solid model of orbiting and fixed scroll is created by the Solidworks The deformation and stress of scrolls under gas force, temperature field, inertia force and the coupling field are analyzed using the Ansys software. The deformation for different thickness and height scroll tooth is investigated. The laws of deformation and stress for scrolls are gotten. The research results indicate that the stress and deformation of orbiting scroll are mainly affected by the temperature field. The maximum deformation occurs in the tooth head of scroll wrap because of the largest gas forces and the highest temperature in the tooth head of scroll wrap. The maximum stress is located in the end of the tooth, and the maximum stress of the coupling field is not the sum of loads. The scroll tooth is higher, and the deformation is bigger. The scroll tooth is thicker, and the deformation is smaller.

  15. Stress and Fracture Analyses Under Elastic-plastic and Creep Conditions: Some Basic Developments and Computational Approaches

    Science.gov (United States)

    Reed, K. W.; Stonesifer, R. B.; Atluri, S. N.

    1983-01-01

    A new hybrid-stress finite element algorith, suitable for analyses of large quasi-static deformations of inelastic solids, is presented. Principal variables in the formulation are the nominal stress-rate and spin. A such, a consistent reformulation of the constitutive equation is necessary, and is discussed. The finite element equations give rise to an initial value problem. Time integration has been accomplished by Euler and Runge-Kutta schemes and the superior accuracy of the higher order schemes is noted. In the course of integration of stress in time, it has been demonstrated that classical schemes such as Euler's and Runge-Kutta may lead to strong frame-dependence. As a remedy, modified integration schemes are proposed and the potential of the new schemes for suppressing frame dependence of numerically integrated stress is demonstrated. The topic of the development of valid creep fracture criteria is also addressed.

  16. Nighttime radiative cooling potential of unglazed and PV/T solar collectors: parametric and experimental analyses

    DEFF Research Database (Denmark)

    Pean, Thibault Quentin; Gennari, Luca; Olesen, Bjarne W.

    2015-01-01

    Nighttime radiative cooling technology has been studied both by means of simulations and experiments, to evaluate its potential and to validate the existing theoretical models used to describe it. Photovoltaic/thermal panels (PV/T) and unglazed solar collectors have been chosen as case studies....... The obtained values showed a good agreement with the ones found in the literature about solar panels or other kinds of heat sinks used for radiative cooling applications. The panels provided a cooling performance per night ranging between 0.2 and 0.9 kWh/m2 of panel. The COP values (defined as the ratio....... An experimental setup has been constructed and tested during summer of 2014, at the Technical University of Denmark. The cooling performance (heat loss) has been measured simultaneously for both types of panels, installed side-by-side. The experimental results have been compared with the results from a commercial...

  17. Numerical and experimental study of the thermal stress of silicon induced by a millisecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xi; Qin Yuan; Wang Bin; Zhang Liang; Shen Zhonghua; Lu Jian; Ni Xiaowu

    2011-07-20

    A spatial axisymmetric finite element model of single-crystal silicon irradiated by a 1064 nm millisecond laser is used to investigate the thermal stress damage induced by a millisecond laser. The transient temperature field and the thermal stress field for 2 ms laser irradiation with a laser fluence of 254 J/cm{sup 2} are obtained. The numerical simulation results indicate that the hoop stresses along the r axis on the front surface are compressive stress within the laser spot and convert to tensile stress outside the laser spot, while the radial stresses along the r axis on the front surface and on the z axis are compressive stress. The temperature of the irradiated center is the highest temperature obtained, yet the stress is not always highest during laser irradiation. At the end of the laser irradiation, the maximal hoop stress is located at r=0.5 mm and the maximal radial stress is located at r=0.76 mm. The temperature measurement experiments are performed by IR pyrometer. The numerical result of the temperature field is consistent with the experimental result. The damage morphologies of silicon under the action of a 254 J/cm{sup 2} laser are inspected by optical microscope. The cracks are observed initiating at r=0.5 mm and extending along the radial direction.

  18. Increase of crevicular interleukin 1beta under academic stress at experimental gingivitis sites and at sites of perfect oral hygiene.

    Science.gov (United States)

    Deinzer, R; Förster, P; Fuck, L; Herforth, A; Stiller-Winkler, R; Idel, H

    1999-01-01

    This study analyses the effects of academic stress on crevicular interleukin-1beta(I1-1beta) both at experimental gingivitis sites and at sites of perfect oral hygiene. I1-1beta is thought to play a predominant role in periodontal tissue destruction. 13 medical students participating in a major medical exam (exam group) and 13 medical students not participating in any exam throughout the study period (control group) volunteered for the study. In a split-mouth-design, they refrained from any oral hygiene procedures in two opposite quadrants for 21 days (experimental gingivitis) while they maintained perfect hygiene levels at the remaining sites. Crevicular fluid was sampled for further I1-1beta analysis at teeth 5 and 6 of the upper jaw at days 1, 5, 8, 11, 14, 18 and 21 of the experimental gingivitis period. Exam students showed significantly higher I1-1beta levels than controls both at experimental gingivitis sites (area under the curve, exam group: 1240.64+/-140.07; control group: 697.61+/-111.30; p=0.004) and at sites of perfect oral hygiene (exam group: 290.42+/-63.19; control group: 143.98+/-42.71; p = 0.04). These results indicate that stress might affect periodontal health by increasing local I1-1beta levels especially when oral hygiene is neglected.

  19. Influence of Impeller Geometry on the Unsteady Flow in a Centrifugal Fan: Numerical and Experimental Analyses

    Directory of Open Access Journals (Sweden)

    M. Younsi

    2007-01-01

    Full Text Available The aim of this study is to evaluate the influence of design parameters on the unsteady flow in a forward-curved centrifugal fan and their impact on the aeroacoustic behavior. To do so, numerical and experimental studies have been carried out on four centrifugal impellers designed with various geometrical parameters. The same volute casing has been used to study these impellers. The effects on the unsteady flow behavior related to irregular blade spacing, blade count and radial distance between the impeller periphery and the volute tongue have been studied. The numerical simulations of the unsteady flow have been carried out using computational fluid dynamics (CFD tools based on the unsteady Reynolds averaged Navier Stokes (URANS approach. The study is focused on the unsteadiness induced by the aerodynamic interaction between the volute and the rotating impeller blades. In order to predict the acoustic pressure at far field, the unsteady flow variables provided by the CFD calculations have been used as inputs in the Ffowcs Williams-Hawkings equations (FW-H. The experimental part of this work concerns measurement of aerodynamic performance of the fans using a test bench built according to ISO 5801 (1997 standard. In addition to this, pressure microphones have been flush mounted on the volute tongue surface in order to measure the wall pressure fluctuations. The sound pressure level (SPL measurements have been carried out in an anechoic room in order to remove undesired noise reflections. Finally, the numerical results have been compared with the experimental measurements and a correlation between the wall pressure fluctuations and the far field noise signals has been found.

  20. Experimental and numerical analyses of adhesively bonded T-joints under crash loading

    Directory of Open Access Journals (Sweden)

    Voß H.

    2012-08-01

    Full Text Available Adhesively bonded metallic T-joints were subjected to impact at different loading directions and loading rates ranging from quasi-static to crash. Different damage and failure mechanisms were observed depending on the loading configuration. Finite element simulations were performed with ABAQUS/explicit using a user-defined, fully rate dependent material model for cohesive elements describing the material response of the adhesive bond lines. The FE simulation results were in good agreement with the experimental evidence, capturing both, the observed damage mechanisms, and the recorded force-displacement response.

  1. Cardioprotective effect of amlodipine in oxidative stress induced by experimental myocardial infarction in rats

    Directory of Open Access Journals (Sweden)

    Sudhira Begum

    2007-12-01

    Full Text Available The present study investigated whether the administration of amlodipine ameliorates oxidative stress induced by experimental myocardial infarction in rats. Adrenaline was administered and myocardial damage was evaluated biochemically [significantly increased serum aspertate aminotransferase (AST, lactate dehydrogenase (LDH and malondialdehyde (MDA levels of myocardial tissue] and histologically (morphological changes of myocardium. Amlodipine was administered as pretreatment for 14 days in adrenaline treated rats. Statistically significant amelioration in all the biochemical parameters supported by significantly improved myocardial morphology was observed in amlodipine pretreatment. It was concluded that amlodipine afforded cardioprotection by reducing oxidative stress induced in experimental myocardial infarction of catecholamine assault.

  2. The relationship between interpersonal traits and posttraumatic stress disorder symptoms: analyses from Wenchuan earthquake adolescent survivors in China.

    Science.gov (United States)

    Xia, Ling-Xiang; Ding, Cody

    2011-08-01

    This study explores the relationship between interpersonal traits and posttraumatic stress disorder (PTSD) symptoms in a sample of 617 middle and high school students 16 months after the Wenchuan earthquake in China using the Impact of Event Scale-Revised (IES-R) and the Interpersonal Self-Supporting Scale (ISSS). Even when the effects of gender and grade level were controlled for, the results from regression analyses revealed that greater interpersonal independence, interpersonal initiative, interpersonal responsibility, and interpersonal openness are associated with lesser PTSD symptoms 16 months later. Copyright © 2011 International Society for Traumatic Stress Studies.

  3. Visualization of Oxidative Stress Induced by Experimental Periodontitis in Keap1-Dependent Oxidative Stress Detector-Luciferase Mice.

    Science.gov (United States)

    Kataoka, Kota; Ekuni, Daisuke; Tomofuji, Takaaki; Irie, Koichiro; Kunitomo, Muneyoshi; Uchida, Yoko; Fukuhara, Daiki; Morita, Manabu

    2016-11-16

    The aim of this study was to investigate whether a Keap1-dependent oxidative stress detector-luciferase (OKD-LUC) mouse model would be useful for the visualization of oxidative stress induced by experimental periodontitis. A ligature was placed around the mandibular first molars for seven days to induce periodontitis. Luciferase activity was measured with an intraperitoneal injection of d-luciferin on days 0, 1, and 7. The luciferase activity in the periodontitis group was significantly greater than that in the control group at seven days. The expressions of heme oxygenase-1 (HO-1) and malondialdehyde in periodontal tissue were significantly higher in the periodontitis group than in the control group. Immunofluorescent analysis confirmed that the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) occurred more frequently in the periodontitis group than in the control group. This study found that under oxidative stress induced by experimental periodontitis, the Nrf2/antioxidant defense pathway was activated and could be visualized from the luciferase activity in the OKD-LUC model. Thus, the OKD-LUC mouse model may be useful for exploring the mechanism underlying the relationship between the Nrf2/antioxidant defense pathway and periodontitis by enabling the visualization of oxidative stress over time.

  4. Oxidative Stress Associated with Neuronal Apoptosis in Experimental Models of Epilepsy

    Directory of Open Access Journals (Sweden)

    Marisela Méndez-Armenta

    2014-01-01

    Full Text Available Epilepsy is considered one of the most common neurological disorders worldwide. Oxidative stress produced by free radicals may play a role in the initiation and progression of epilepsy; the changes in the mitochondrial and the oxidative stress state can lead mechanism associated with neuronal death pathway. Bioenergetics state failure and impaired mitochondrial function include excessive free radical production with impaired synthesis of antioxidants. This review summarizes evidence that suggest what is the role of oxidative stress on induction of apoptosis in experimental models of epilepsy.

  5. The specific heat loss combined with the thermoelastic effect for an experimental analysis of the mean stress influence on axial fatigue of stainless steel plain specimens

    Directory of Open Access Journals (Sweden)

    G. Meneghetti

    2014-10-01

    Full Text Available The energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, was recently proposed by the authors as fatigue damage index and it was successfully applied to correlate fatigue data obtained by carrying out fully reversed stress- and strain-controlled fatigue tests on AISI 304L stainless steel plain and notched specimens. The use of the Q parameter to analyse the experimental results led to the definition of a scatter band having constant slope from the low- to the high-cycle fatigue regime. In this paper the energy approach is extended to analyse the influence of mean stress on the axial fatigue behaviour of unnotched cold drawn AISI 304L stainless steel bars. In view of this, stress controlled fatigue tests on plain specimens at different load ratios R (R=-1; R=0.1; R=0.5 were carried out. A new energy parameter is defined to account for the mean stress effect, which combines the specific heat loss Q and the relative temperature variation due to the thermoelastic effect corresponding to the achievement of the maximum stress level of the stress cycle. The new two-parameter approach was able to rationalise the mean stress effect observed experimentally. It is worth noting that the results found in the present contribution are meant to be specific for the material and testing condition investigated here.

  6. Inhibitory effects of alprazolam on the development of acute experimental autoimmune encephalomyelitis in stressed rats.

    Science.gov (United States)

    Núñez-Iglesias, María J; Novío, Silvia; Almeida-Dias, Antonio; Freire-Garabal, Manuel

    2010-12-01

    The progression and development of multiple sclerosis (MS) has long been hypothesized to be associated with stress. Benzodiazepines have been observed to reduce negative consequences of stress on the immune system in experimental and clinical models, but there are no data on their effects on MS, or experimental autoimmune encephalomyelitis (EAE), a model for human MS. We designed experiments conducted to ascertain whether alprazolam could modify the clinical, histological and neuroendocrine manifestations of acute EAE in Lewis rats exposed to a chronic auditory stressor. EAE was induced by injection of an emulsion of MBP and complete Freund's adjuvant containing Mycobacterium tuberculosis H37Ra. Stress application and treatment with drugs (placebo or alprazolam) were initiated 5days before inoculation and continued daily for the duration of the experiment (days 14 or 34 postinoculation).Our results show significant increases in the severity of neurological signs, the histological lesions of the spinal cord (inflammation), and the corticosterone plasmatic levels in stressed rats compared to those non-stressed ones. Treatment with alprazolam reversed the adverse effects of stress. These findings could have clinical implications in patients suffering from MS treated with benzodiazepines, so besides the psychopharmacological properties of alprazolam against stress, it has beneficial consequences on EAE. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Numerical and experimental study of moisture-induced stress and strain field developments in timber logs

    DEFF Research Database (Denmark)

    Larsen, Finn; Ormarsson, Sigurdur

    2013-01-01

    When solid wood dries from a green condition to a moisture content used for further processing, moisture-induced fracture and stresses can occur. The drying stresses arise because of internal deformation constraints that are strongly affected by the cross-sectional moisture gradient differential...... shrinkage and the inhomogeneity of the material. To obtain a better understanding of how stresses develop during climatic variations, the field histories of stresses (and strains) in cross sections in their entirety need to be studied. The present paper reports on experiments and numerical simulations...... concerned with analysing the development of strains and stresses during the drying of 15-mm-thick discs of Norway spruce timber log. The samples were dried at 23 °C and relative humidity of 64 % from a green condition to equilibrium moisture content. The moisture gradient in the longitudinal direction...

  8. Structural Response of Submerged Air-Backed Plates by Experimental and Numerical Analyses

    Directory of Open Access Journals (Sweden)

    Lloyd Hammond

    2000-01-01

    Full Text Available This paper presents the results of a series of small-scale underwater shock experiments that measured the structural responses of submerged, fully clamped, air-backed, steel plates to a range of high explosive charge sizes. The experimental results were subsequently used to validate a series of simulations using the coupled LS-DYNA/USA finite element/boundary element codes. The modelling exercise was complicated by a significant amount of local cavitation occurring in the fluid adjacent to the plate and difficulties in modelling the boundary conditions of the test plates. The finite element model results satisfactorily predicted the displacement-time history of the plate over a range of shock loadings although a less satisfactory correlation was achieved for the peak velocities. It is expected that the predictive capability of the finite element model will be significantly improved once hydrostatic initialisation can be fully utilised with the LS-DYNA/USA software.

  9. Trehalose treatment suppresses inflammation, oxidative stress, and vasospasm induced by experimental subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Echigo Ryosuke

    2012-04-01

    Full Text Available Abstract Background Subarachnoid hemorrhage (SAH frequently results in several complications, including cerebral vasospasm, associated with high mortality. Although cerebral vasospasm is a major cause of brain damages after SAH, other factors such as inflammatory responses and oxidative stress also contribute to high mortality after SAH. Trehalose is a non-reducing disaccharide in which two glucose units are linked by α,α-1,1-glycosidic bond, and has been shown to induce tolerance to a variety of stressors in numerous organisms. In the present study, we investigated the effect of trehalose on cerebral vasospasm, inflammatory responses, and oxidative stress induced by blood in vitro and in vivo. Methods Enzyme immunoassay for eicosanoids, pro-inflammatory cytokines, and endothelin-1, and western blotting analysis for cyclooxygenase-2, inducible nitric oxide synthase, and inhibitor of NF-κB were examined in macrophage-like cells treated with hemolysate. After treatment with hemolysate and hydrogen peroxide, the levels of lipid peroxide and amounts of arachidonic acid release were also analyzed. Three hours after the onset of experimental SAH, 18 Japanese White rabbits received an injection of saline, trehalose, or maltose into the cisterna magna. Angiographic and histological analyses of the basilar arteries were performed. In a separate study, the femoral arteries from 60 rats were exposed to fresh autologous blood. At 1, 3, 5, 7, 10, and 20 days after treatment, cryosections prepared from the femoral arteries were histologically analyzed. Results When cells were treated with hemolysate, trehalose inhibited the production of several inflammatory mediators and degradation of the inhibitor of NF-κB and also suppressed the lipid peroxidation, the reactive oxygen species-induced arachidonic acid release in vitro. In the rabbit model, trehalose produced an inhibitory effect on vasospasm after the onset of experimental SAH, while maltose had only

  10. Towards a synthetic view of potato cold and salt stress response by transcriptomic and proteomic analyses.

    Science.gov (United States)

    Evers, D; Legay, S; Lamoureux, D; Hausman, J F; Hoffmann, L; Renaut, J

    2012-03-01

    Potato can suffer from several abiotic stresses such as cold temperature, high soil salinity, lack of water or heavy metal exposure, to name a few. They are known to affect plant growth as well as productivity, with differential regulations at several levels. Potato response to cold and salt exposure was investigated at both transcriptomic and proteomic levels in a growth chamber experiment. Cold exposure in potato resulted in a higher number of significantly differentially regulated genes compared to salt exposure, whereas there were nearly three times more differentially regulated proteins after salt exposure when compared to cold exposure. The allocation of up and down-regulated genes at the functional category level also differed between salt and cold exposure although common trends, previously described in various abiotic stresses, were observed. In both stresses, the majority of photosynthesis-related genes were down-regulated whereas cell rescue and transcription factor-related genes were mostly up-regulated. In the other functional categories no common trend was observed; salt exposure results displayed a strong down-regulation of genes implicated in primary metabolism, detoxication apparatus and signal transduction, whereas upon cold exposure, up and down-regulated genes were similar in number. At the proteomic level, the abundance of the majority of identified proteins was increased except for the photosynthesis-related proteins, which were mostly less abundant after both salt and cold exposure. Common responses between salt and cold stress and specific responses inherent to these abiotic stresses are described.

  11. Performance of grain sorghum hybrids under drought stress using GGE biplot analyses.

    Science.gov (United States)

    Batista, P S C; Menezes, C B; Carvalho, A J; Portugal, A F; Bastos, E A; Cardoso, M J; Santos, C V; Julio, M P M

    2017-09-21

    The objective of this study was to estimate the adaptability and stability of grain sorghum hybrids grown under post-flowering water stress and non-stress conditions. The trials were carried out in Nova Porteirinha-MG during the season of 2014 and 2015, and in Teresina-PI in the 2014 season. Twenty-nine-grain sorghum hybrids were evaluated, in a randomized complete block design, with three replications. Plots consisted of four lines with 3 m long. The grain yield data were submitted to the individual variance analysis, having considered the effects of the hybrids as fixed and the other effects as random. The joint analysis was carried out, and when the interaction genotypes x environments was significant, the grain yield data were submitted to the adaptability and stability analysis by the GGE biplot method. A substantial reduction in the grain yield in environments with water stress was found. The highest yielding hybrids under water stress conditions in Nova Porteirinha-MG were 50A50, AG1080, AG1090, DKB550, DKB590, Jade, and BM737, and the highest yielding hybrids under the water stress in Teresina-PI were 1G282, 1G244, and A9721R. Considering all environments, the highest yielding hybrids were 1G282, DKB540, A9721R, 1G100, and AG1090.

  12. Experimental stress analysis and fatigue tests of five 24-in. NPS ANSI Standard B16. 9 tees. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Moore, S.E.; Hayes, J.K.; Weed, R.A.

    1985-03-01

    Experimental stress analyses and low-cycle fatigue tests of five 24-in. nominal pipe size American National Standards Institute (ANSI) Standard B16.9 forged tees are documented in this report. The tees, designated as Oak Ridge National Laboratory tees T10, T11, T12, T13, and T16, were tested under subcontract at Combustion Engineering, Inc. in Chattanooga, Tennessee. Experimental stress analyses were conducted for 12 individual loadings on each tee. Each test model was instrumented with approx. 225, 1/8-in. three-gage, 45/sup 0/ strain rosettes on the inside and outside surfaces; and 6 linear variable differential transformers mounted on special nonflexible holding frames for measuring deflections and rotations of the pipe extensions. Following completion of the strain-gate tests, each tee was fatigue tested to failure with either a fully reversed displacement controlled in-plane bending moment on the branch or a cyclic internal pressure that ranged from a value slightly above zero to about 90% of the nominal yield pressure of the pipe extensions.

  13. 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.

  14. Physiological and proteomic analyses of Saccharum spp. grown under salt stress.

    Directory of Open Access Journals (Sweden)

    Aline Melro Murad

    Full Text Available Sugarcane (Saccharum spp. is the world most productive sugar producing crop, making an understanding of its stress physiology key to increasing both sugar and ethanol production. To understand the behavior and salt tolerance mechanisms of sugarcane, two cultivars commonly used in Brazilian agriculture, RB867515 and RB855536, were submitted to salt stress for 48 days. Physiological parameters including net photosynthesis, water potential, dry root and shoot mass and malondialdehyde (MDA content of leaves were determined. Control plants of the two cultivars showed similar values for most traits apart from higher root dry mass in RB867515. Both cultivars behaved similarly during salt stress, except for MDA levels for which there was a delay in the response for cultivar RB867515. Analysis of leaf macro- and micronutrients concentrations was performed and the concentration of Mn(2+ increased on day 48 for both cultivars. In parallel, to observe the effects of salt stress on protein levels in leaves of the RB867515 cultivar, two-dimensional gel electrophoresis followed by MS analysis was performed. Four proteins were differentially expressed between control and salt-treated plants. Fructose 1,6-bisphosphate aldolase was down-regulated, a germin-like protein and glyceraldehyde 3-phosphate dehydrogenase showed increased expression levels under salt stress, and heat-shock protein 70 was expressed only in salt-treated plants. These proteins are involved in energy metabolism and defense-related responses and we suggest that they may be involved in protection mechanisms against salt stress in sugarcane.

  15. Experimental and Numerical Analyses of a Flat Plate Photovoltaic/Thermal Solar Collector

    Directory of Open Access Journals (Sweden)

    Francesco Calise

    2017-04-01

    Full Text Available This paper presents a one-dimensional finite-volume model of an unglazed photovoltaic/thermal (PVT solar collector. The unit consists of a conventional solar photovoltaic (PV collector coupled with a suitable heat exchanger. In particular, the collector includes a roll bond heat exchanger and it is not equipped with back and frame insulation. The system is discretized along the flow direction (longitudinal of the cogenerative collector. For each finite-volume element of the discretized computational domain, mass and energy balances are implemented. The collector geometry and materials parameters are taken from a commercially available device. An on-field experimental investigation is performed in order to validate the proposed model. The model is used to evaluate both electrical and thermodynamic parameters for each element of the domain and for fixed operating conditions. Finally, a sensitivity analysis is also performed in order to investigate the energetic performance of the cogenerative collector as a function of the main design/environmental parameters.

  16. [Experimental investigation of quantitatively analysing trace Mo in complex metallic alloys by laser induced breakdown spectroscopy].

    Science.gov (United States)

    Wang, Zhen-Nan; Li, Ying; Zhang, Qing-Yu; Lu, Yuan; Zheng, Rong-Er

    2011-06-01

    The quantitative analysis using laser induced breakdown spectroscopy (LIBS), lack of appropriate interior label element, is described and applied to trace element molybdenum (Mo) detection in complex metallic alloys. A Q-switched Nd : YAG laser operating at 532 nm was utilized to generate plasma and the emission was recorded by a grating spectrometer equipped with CCD, boxcar and PMT. The three peak heights of Mo I , 550.649, 553.305 and 557.045 nm, changing with Mo mass fraction in metallic alloys were measured to produce calibration curves respectively, and double blind method was used to analyse a test sample. Based on Mo I 550.649 nm line, the Mo mass fraction in the test sample was determined to be 2.229% with relative error of 5.57% in comparison with the given value of 2.111%. On using Mo I 557.045 nm line, the relative error was found to be doubled due to the overlap with Fe emission lines. While taking the total height of three atomic lines into account in analysis, the resulted error dropped to 7.58%, even better than the average of predicted concentrations based on the above three lines. The obtained results demonstrate that satisfactory precision could be obtained under a consistent experiment condition with the above scheme, even without appropriate interior label element. The methods of maintaining stable laser ablation efficiency on sample are also discussed.

  17. EXPERIMENTAL ANALYSES OF SPALLATION NEUTRONS GENERATED BY 100 MEV PROTONS AT THE KYOTO UNIVERSITY CRITICAL ASSEMBLY

    Directory of Open Access Journals (Sweden)

    CHEOL HO PYEON

    2013-02-01

    Full Text Available Neutron spectrum analyses of spallation neutrons are conducted in the accelerator-driven system (ADS facility at the Kyoto University Critical Assembly (KUCA. High-energy protons (100 MeV obtained from the fixed field alternating gradient accelerator are injected onto a tungsten target, whereby the spallation neutrons are generated. For neutronic characteristics of spallation neutrons, the reaction rates and the continuous energy distribution of spallation neutrons are measured by the foil activation method and by an organic liquid scintillator, respectively. Numerical calculations are executed by MCNPX with JENDL/HE-2007 and ENDF/B-VI libraries to evaluate the reaction rates of activation foils (bismuth and indium set at the target and the continuous energy distribution of spallation neutrons set in front of the target. For the reaction rates by the foil activation method, the C/E values between the experiments and the calculations are found around a relative difference of 10%, except for some reactions. For continuous energy distribution by the organic liquid scintillator, the spallation neutrons are observed up to 45 MeV. From these results, the neutron spectrum information on the spallation neutrons generated at the target are attained successfully in injecting 100 MeV protons onto the tungsten target.

  18. Biochemical and proteomic analyses of the physiological response induced by individual housing in gilts provide new potential stress markers

    OpenAIRE

    Marco Ramell, Anna; Arroyo, Laura; Peña, Raquel; Pato, Raquel; Saco, Yolanda; Fraile Sauce, Lorenzo José; Bendixen, Emøke; Bassols, Anna

    2016-01-01

    Background The objective assessment of animal stress and welfare requires proper laboratory biomarkers. In this work, we have analyzed the changes in serum composition in gilts after switching their housing, from pen to individual stalls, which is generally accepted to cause animal discomfort. Results Blood and saliva samples were collected a day before and up to four days after changing the housing system. Biochemical analyses showed adaptive changes in lipid and protein metabolism after the...

  19. Tensile stress generation by optical breakdown in tissue: Experimental investigations and numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany); Scammon, R.J.; Godwin, R.P. [Los Alamos National Lab., NM (United States)

    1999-03-01

    Biological tissue is more susceptible to damage from tensile stress than to compressive stress. Tensile stress may arise through the thermoelastic response of laser-irradiated media. Optical breakdown, however, has to date been exclusively associated with compressive stress. The authors show that this is appropriate for water, but not for tissues for which the elastic-plastic material response needs to be considered. The acoustic transients following optical breakdown in water and cornea were measured with a fast hydrophone and the cavitation bubble dynamics, which is closely linked to the stress wave generation, was documented by flash photography. Breakdown in water produced a monopolar acoustic signal and a bubble oscillation in which the expansion and collapse phases were symmetric. Breakdown in cornea produced a bipolar acoustic signal coupled with a pronounced shortening of the bubble expansion phase and a considerable prolongation of its collapse phase. The tensile stress wave is related to the abrupt end of the bubble expansion. Numerical simulations using the MESA-2D code were performed assuming elastic-plastic material behavior in a wide range of values for the shear modulus and yield strength. The calculations revealed that consideration of the elastic-plastic material response is essential to reproduce the experimentally observed bipolar stress waves. The tensile stress evolves during the outward propagation of the acoustic transient and reaches an amplitude of 30--40% of the compressive pulse.

  20. Stress analyses for the glass joints of contemporary sodium sulfur batteries

    Science.gov (United States)

    Jung, Keeyoung; Lee, Solki; Kim, Goun; Kim, Chang-Soo

    2014-12-01

    During the manufacturing and thermal cycles of advanced contemporary large sized sodium sulfur (NaS) batteries, thermally driven stresses can be applied to the glass sealing joints, which may result in catastrophic cell failure. To minimize the thermal stresses at the joints, there is a need to develop a method to properly estimate the maximum thermal stresses by varying the materials properties and shapes of the sealing area, and thereby determine the properties and shapes of sealing material at the joints. In the present study, the optimum coefficient of thermal expansion (CTE) of the glass sealant and end shape of the glass sealing area (i.e., concave, flat, and convex shapes) have been determined using the finite-element analysis (FEA) computation technique. The results showed that the CTE value of 7.8 × 10-6 K-1 with a convex end shape would have the lowest stress concentration in the vicinity of glass sealing joints for the prototype tubular NaS cell design adopted in this work.

  1. Comparative proteomic analyses provide new insights into low phosphorus stress responses in maize leaves.

    Directory of Open Access Journals (Sweden)

    Kewei Zhang

    Full Text Available Phosphorus deficiency limits plant growth and development. To better understand the mechanisms behind how maize responds to phosphate stress, we compared the proteome analysis results of two groups of maize leaves that were treated separately with 1,000 µM (control, +P and 5 µM of KH2PO4 (intervention group, -P for 25 days. In total, 1,342 protein spots were detected on 2-DE maps and 15.43% had changed (P<0.05; ≥1.5-fold significantly in quantity between the +P and -P groups. These proteins are involved in several major metabolic pathways, including photosynthesis, carbohydrate metabolism, energy metabolism, secondary metabolism, signal transduction, protein synthesis, cell rescue and cell defense and virulence. The results showed that the reduction in photosynthesis under low phosphorus treatment was due to the down-regulation of the proteins involved in CO2 enrichment, the Calvin cycle and the electron transport system. Electron transport and photosynthesis restrictions resulted in a large accumulation of peroxides. Maize has developed many different reactive oxygen species (ROS scavenging mechanisms to cope with low phosphorus stress, including up-regulating its antioxidant content and antioxidase activity. After being subjected to phosphorus stress over a long period, maize may increase its internal phosphorus utilization efficiency by altering photorespiration, starch synthesis and lipid composition. These results provide important information about how maize responds to low phosphorus stress.

  2. Frictional melting of gabbro under extreme experimental conditions of normal stress, acceleration, and sliding velocity

    NARCIS (Netherlands)

    Niemeijer, A.; Di Toro, G.; Nielsen, S.; Di Felice, F.

    2011-01-01

    With the advent of high‐velocity shear apparatus, several experimental studies have been performed in recent years, improving our understanding of the evolution of fault strength during seismic slip. However, these experiments were conducted under relatively low normal stress (<20 MPa) and using

  3. Experimentally induced stress in rheumatoid arthritis of recent onset: effects on peripheral blood lymphocytes

    NARCIS (Netherlands)

    Geenen, R.; Godaert, G. L.; Heijnen, C. J.; Vianen, M. E.; Wenting, M. J.; Nederhoff, M. G.; Bijlsma, J. W.

    1998-01-01

    To examine the effects of experimentally-induced stress on the mobilization of peripheral blood lymphocytes (PBL) in patients with rheumatoid arthritis (RA) of recent onset. Twenty-two (16 F, 6 M) patients (mean age 57.6 yrs.) and 23 (15 F, 8 M) healthy subjects (mean age 54.7 yrs.) were subjected

  4. Numerical Analysis and Experimental Verification of Stresses Building up in Microelectronics Packaging

    NARCIS (Netherlands)

    Rezaie Adli, A.R.

    2017-01-01

    This thesis comprises a thorough study of the microelectronics packaging process by means of various experimental and numerical methods to estimate the process induced residual stresses. The main objective of the packaging is to encapsulate the die, interconnections and the other exposed internal

  5. A numerical and experimental study of stress and crack development in kiln-dried wood

    DEFF Research Database (Denmark)

    Larsen, Finn; Ormarsson, Sigurdur

    2012-01-01

    Numerical and experimental investigations were carried out on well defined log-disc samples of Norway spruce consisting of both heartwood and sapwood, with the aim of gaining more adequate knowledge of stress and fracture generation during the drying process. Use of thin discs enabled a well-cont...

  6. A numerical and experimental study of stress and crack development in kiln-dried wood

    DEFF Research Database (Denmark)

    Larsen, Finn; Ormarsson, Sigurdur

    2012-01-01

    Numerical and experimental investigations were carried out on well defined log-disc samples of Norway spruce consisting of both heartwood and sapwood, with the aim of gaining more adequate knowledge of stress and fracture generation during the drying process. Use of thin discs of a log enabled a ...

  7. Behaviour study of thick laminated composites: Experimentation and finite element analyses

    Science.gov (United States)

    Duchaine, Francois

    In today's industries, it is common practice to utilize composite materials in very large and thick structures like bridge decks, high pressure vessels, wind turbine blades and aircraft parts to mention a few. Composite materials are highly favoured due to their physical characteristics: low weight, low cost, adaptable mechanical properties, high specific strength and stiffness. The use of composite materials for large structures has however raised several concerns in the prediction of the behaviour of thick laminated composite parts. A lack of knowledge and experience in the use of composite materials during the design, sizing and manufacturing of thick composite parts can lead to catastrophic events. In this thesis, it was supposed that the elastic material properties may vary with the laminate thickness. In order to measure the influence of the thickness on nine orthotropic elastic material properties (E1, E2, E3, nu12, nu 13, nu23, G12, G13 and G23), three categories of thickness have been defined using a comparison between the classical lamination theory (CLT), different beam theories and a numerical 3D solid finite element analysis (FEA) model. The defined categories are: thin laminates for thicknesses below 6 mm (0.236"), moderately thick laminates for thicknesses up to 16 mm (0.630") and thick laminates for thicknesses above 16 mm (0.630"). For three different thicknesses (thin -- 1.5 mm, moderately thick -- 10 mm and thick -- 20 mm), the influence of the thickness on the orthotropic elastic material properties of unidirectional (UD) fibreglass/epoxy laminates has been measured. A torsion test on rectangular bar is also proposed to measure the influence of the thickness on G13 and G23. The nine elastic material properties, in function of the thickness, have been used in CLT and 3D solid FEA model in order to predict the axial Young's modulus and Poisson's ratios of cross-ply and quasi-isotropic laminates. Experimental results have also been obtained for

  8. Experimental and finite element analyses of multifunctional skins for morphing wing applications

    Science.gov (United States)

    Geier, Sebastian; Kintscher, Markus; Mahrholz, Thorsten; Wierach, Peter; Monner, Hans-Peter; Wiedemann, Martin

    2016-04-01

    -up. Based on experimental results a numerical model can be set up for further structural optimizaton of the multi-functional laminate.

  9. Application of Bousinesq's and Westergaard's formulae in analysing foundation stress distribution for a failed telecommunication mast

    CERN Document Server

    Ojedokun, Olalekan Yinka

    2012-01-01

    The concurrent foundation failure of telecommunication masts in Nigeria and all over the world which endanger the lives and properties of residents situated within the fall distance of the telecommunication mast are a thing of great concern. In this study, a GSM mast that underwent foundation failure at Ibadan, Oyo State, Nigeria was critically examined with a view to providing engineering solution. The soil investigation at the global system for mobile communications (GSM) telecommunication tower comprised of laboratory tests: sieve analysis, Atterberg limits and moisture content tests were carried out on the soil samples obtained while Dutch cone penetrometer test was performed on the site to a depth of refusal to determine the allowable bearing pressure at various depths of the soil. The application of Boussineq's and Westergard's formulae for point loads using Java programme to simulate and compute the stress distribution at various predetermined depths showed the stress distribution pattern beneath the f...

  10. Experimental and numerical determination of critical stress intensity factor of aluminum curved thin sheets under tensile stress

    Energy Technology Data Exchange (ETDEWEB)

    Heidarvand, Majid; Soltani, Naser; Hajializadeh, Farshid [University of Tehran, Tehran (Iran, Islamic Republic of)

    2017-05-15

    We determined the fracture toughness of aluminum curved thin sheets using tensile stress tests and finite element method. We applied Linear elastic fracture mechanics (LEFM) and Feddersen procedure to evaluate stress intensity factor of the samples with central wire-cut cracks and fatigue cracks with different lengths to investigate the notch radius effect. Special fixture design was utilized to establish uniform stress distribution at the crack zone. Less than 9 % difference was found between the wire-cut and the fatigue cracked samples. Since generating central fatigue crack with different lengths required so much effort, wire-cut cracked samples were used to determine critical stress intensity factor. Finite element analysis was also performed on one-quarter of the specimen using both the singular Borsum elements and the regular isoparametric elements to further investigate fracture toughness of the samples. It was observed that the singular elements presented better results than the isoparametric ones. A slight difference was also found between the results obtained from finite element method using singular elements and the experimental results.

  11. Experimental and theoretical analysis on the procedure for estimating geo-stresses by the Kaiser effect

    Science.gov (United States)

    Li, Yuan-Hui; Yang, Yu-Jiang; Liu, Jian-Po; Zhao, Xing-Dong

    2010-10-01

    Acoustic emission tests of the core specimens retrieved from boreholes at the depth over 1000 m in Hongtoushan Copper Mine were carried out under uniaxial compressive loading, and the numerical test was also done by using the rock failure process analysis (RFPA2D) code, based on the procedure for estimating geo-stresses by the Kaiser effect under uniaxial compression. According to the statistical damage mechanics theory, the Kaiser effect mechanism was analyzed. Based on these analyses, it is indicted that the traditional method of estimating geo-stresses by the Kaiser effect is not appropriate, and the result is usually smaller than the real one. Furthermore, the greater confining compression in the rock mass may result in a larger difference between the Kaiser effect stresses acquired from uniaxial loading in laboratory and the real in-situ stresses.

  12. Patient-specific stress analyses in the ascending thoracic aorta using a finite-element implementation of the constrained mixture theory.

    Science.gov (United States)

    Mousavi, S Jamaleddin; Avril, Stéphane

    2017-05-23

    It is now a rather common approach to perform patient-specific stress analyses of arterial walls using finite-element models reconstructed from gated medical images. However, this requires to compute for every Gauss point the deformation gradient between the current configuration and a stress-free reference configuration. It is technically difficult to define such a reference configuration, and there is actually no guarantee that a stress-free configuration is physically attainable due to the presence of internal stresses in unloaded soft tissues. An alternative framework was proposed by Bellini et al. (Ann Biomed Eng 42(3):488-502, 2014). It consists of computing the deformation gradients between the current configuration and a prestressed reference configuration. We present here the first finite-element results based on this concept using the Abaqus software. The reference configuration is set arbitrarily to the in vivo average geometry of the artery, which is obtained from gated medical images and is assumed to be mechanobiologically homeostatic. For every Gauss point, the stress is split additively into the contributions of each individual load-bearing constituent of the tissue, namely elastin, collagen, smooth muscle cells. Each constituent is assigned an independent prestretch in the reference configuration, named the deposition stretch. The outstanding advantage of the present approach is that it simultaneously computes the in situ stresses existing in the reference configuration and predicts the residual stresses that occur after removing the different loadings applied onto the artery (pressure and axial load). As a proof of concept, we applied it on an ideal thick-wall cylinder and showed that the obtained results were consistent with corresponding experimental and analytical results of the well-known literature. In addition, we developed a patient-specific model of a human ascending thoracic aneurysmal aorta and demonstrated the utility in predicting the

  13. Proteomic and Physiological Analyses Reveal Putrescine Responses in Roots of Cucumber Stressed by NaCl

    Directory of Open Access Journals (Sweden)

    Yinghui Yuan

    2016-07-01

    Full Text Available Soil salinity is a major environmental constraint that threatens agricultural productivity. Different strategies have been developed to improve crop salt tolerance, among which the effects of polyamines have been well reported. To gain a better understanding of the cucumber (Cucumis sativus L. responses to NaCl and unravel the underlying mechanism of exogenous putrescine (Put alleviating salt-induced damage, comparative proteomic analysis was conducted on cucumber roots treated with NaCl and/or Put for 7 days. The results showed that exogenous Put restored the root growth inhibited by NaCl. 62 differentially expressed proteins implicated in various biological processes were successfully identified by MALDI-TOF/TOF MS. The four largest categories included proteins involved in defense response (24.2%, protein metabolism (24.2%, carbohydrate metabolism (19.4% and amino acid metabolism (14.5%. Exogenous Put up-regulated most identified proteins involved in carbohydrate metabolism, implying an enhancement in energy generation. Proteins involved in defense response and protein metabolism were differently regulated by Put, which indicated the roles of Put in stress resistance and proteome rearrangement. Put also increased the abundance of proteins involved in amino acid metabolism. Meanwhile, physiological analysis showed that Put could further up-regulated the levels of free amino acids in salt stressed-roots. In addition, Put also improved endogenous polyamines contents by regulating the transcription levels of key enzymes in polyamine metabolism. Taken together, these results suggest that Put may alleviate NaCl-induced growth inhibition through degradation of misfolded/damaged proteins, activation of stress defense, and the promotion of carbohydrate metabolism to generate more energy.

  14. Three-dimensional elastic--plastic stress and strain analyses for fracture mechanics: complex geometries

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, H.J.

    1975-11-01

    The report describes the continuation of research into capability for three-dimensional elastic-plastic stress and strain analysis for fracture mechanics. A computer program, MARC-3D, has been completed and was used to analyze a cylindrical pressure vessel with a nozzle insert. A method for generating crack tip elements was developed and a model was created for a cylindrical pressure vessel with a nozzle and an imbedded flaw at the inside nozzle corner. The MARC-3D program was again used to analyze this flawed model. Documentation for the use of the MARC-3D computer program has been included as an appendix.

  15. Bioinformatic and expression analyses on carotenoid dioxygenase genes in fruit development and abiotic stress responses in Fragaria vesca.

    Science.gov (United States)

    Wang, Yong; Ding, Guanqun; Gu, Tingting; Ding, Jing; Li, Yi

    2017-08-01

    Carotenoid dioxygenases, including 9-cis-epoxycarotenoid dioxygenases (NCEDs) and carotenoid cleavage dioxygenases (CCDs), can selectively cleave carotenoids into various apocarotenoid products that play important roles in fleshy fruit development and abiotic stress response. In this study, we identified 12 carotenoid dioxygenase genes in diploid strawberry Fragaria vesca, and explored their evolution with orthologous genes from nine other species. Phylogenetic analyses suggested that the NCED and CCDL groups moderately expanded during their evolution, whereas gene numbers of the CCD1, CCD4, CCD7, and CCD8 groups maintained conserved. We characterized the expression profiles of FveNCED and FveCCD genes during flower and fruit development, and in response to several abiotic stresses. FveNCED1 expression positively responded to osmotic, cold, and heat stresses, whereas FveNCED2 was only induced under cold stress. In contrast, FveNCED2 was the unique gene highly and continuously increasing in receptacle during fruit ripening, which co-occurred with the increase in endogenous abscisic acid (ABA) content previously reported in octoploid strawberry. The differential expression patterns suggested that FveNCED1 and FveNCED2 were key genes for ABA biosynthesis in abiotic stress responses and fruit ripening, respectively. FveCCD1 exhibited the highest expression in most stages of flower and fruit development, while the other FveCCDs were expressed in a subset of stages and tissues. Our study suggests distinct functions of FveNCED and FveCCD genes in fruit development and stress responses and lays a foundation for future study to understand the roles of these genes and their metabolites, including ABA and other apocarotenoid products, in the growth and development of strawberry.

  16. Optimizing laboratory animal stress paradigms: The H-H* experimental design.

    Science.gov (United States)

    McCarty, Richard

    2017-01-01

    Major advances in behavioral neuroscience have been facilitated by the development of consistent and highly reproducible experimental paradigms that have been widely adopted. In contrast, many different experimental approaches have been employed to expose laboratory mice and rats to acute versus chronic intermittent stress. An argument is advanced in this review that more consistent approaches to the design of chronic intermittent stress experiments would provide greater reproducibility of results across laboratories and greater reliability relating to various neural, endocrine, immune, genetic, and behavioral adaptations. As an example, the H-H* experimental design incorporates control, homotypic (H), and heterotypic (H*) groups and allows for comparisons across groups, where each animal is exposed to the same stressor, but that stressor has vastly different biological and behavioral effects depending upon each animal's prior stress history. Implementation of the H-H* experimental paradigm makes possible a delineation of transcriptional changes and neural, endocrine, and immune pathways that are activated in precisely defined stressor contexts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Comparisons of RELAP5-3D Analyses to Experimental Data from the Natural Convection Shutdown Heat Removal Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Bucknor, Matthew; Hu, Rui; Lisowski, Darius; Kraus, Adam

    2016-04-17

    The Reactor Cavity Cooling System (RCCS) is an important passive safety system being incorporated into the overall safety strategy for high temperature advanced reactor concepts such as the High Temperature Gas- Cooled Reactors (HTGR). The Natural Convection Shutdown Heat Removal Test Facility (NSTF) at Argonne National Laboratory (Argonne) reflects a 1/2-scale model of the primary features of one conceptual air-cooled RCCS design. The project conducts ex-vessel, passive heat removal experiments in support of Department of Energy Office of Nuclear Energy’s Advanced Reactor Technology (ART) program, while also generating data for code validation purposes. While experiments are being conducted at the NSTF to evaluate the feasibility of the passive RCCS, parallel modeling and simulation efforts are ongoing to support the design, fabrication, and operation of these natural convection systems. Both system-level and high fidelity computational fluid dynamics (CFD) analyses were performed to gain a complete understanding of the complex flow and heat transfer phenomena in natural convection systems. This paper provides a summary of the RELAP5-3D NSTF model development efforts and provides comparisons between simulation results and experimental data from the NSTF. Overall, the simulation results compared favorably to the experimental data, however, further analyses need to be conducted to investigate any identified differences.

  18. Genomic and transcriptomic analyses of the tangerine pathotype of Alternaria alternata in response to oxidative stress.

    Science.gov (United States)

    Wang, Mingshuang; Sun, Xuepeng; Yu, Dongliang; Xu, Jianping; Chung, Kuangren; Li, Hongye

    2016-09-01

    The tangerine pathotype of Alternaria alternata produces the A. citri toxin (ACT) and is the causal agent of citrus brown spot that results in significant yield losses worldwide. Both the production of ACT and the ability to detoxify reactive oxygen species (ROS) are required for A. alternata pathogenicity in citrus. In this study, we report the 34.41 Mb genome sequence of strain Z7 of the tangerine pathotype of A. alternata. The host selective ACT gene cluster in strain Z7 was identified, which included 25 genes with 19 of them not reported previously. Of these, 10 genes were present only in the tangerine pathotype, representing the most likely candidate genes for this pathotype specialization. A transcriptome analysis of the global effects of H2O2 on gene expression revealed 1108 up-regulated and 498 down-regulated genes. Expressions of those genes encoding catalase, peroxiredoxin, thioredoxin and glutathione were highly induced. Genes encoding several protein families including kinases, transcription factors, transporters, cytochrome P450, ubiquitin and heat shock proteins were found associated with adaptation to oxidative stress. Our data not only revealed the molecular basis of ACT biosynthesis but also provided new insights into the potential pathways that the phytopathogen A. alternata copes with oxidative stress.

  19. Experimental Research of Reliability of Plant Stress State Detection by Laser-Induced Fluorescence Method

    Directory of Open Access Journals (Sweden)

    Yury Fedotov

    2016-01-01

    Full Text Available Experimental laboratory investigations of the laser-induced fluorescence spectra of watercress and lawn grass were conducted. The fluorescence spectra were excited by YAG:Nd laser emitting at 532 nm. It was established that the influence of stress caused by mechanical damage, overwatering, and soil pollution is manifested in changes of the spectra shapes. The mean values and confidence intervals for the ratio of two fluorescence maxima near 685 and 740 nm were estimated. It is presented that the fluorescence ratio could be considered a reliable characteristic of plant stress state.

  20. Individually ventilated cages impose cold stress on laboratory mice: a source of systemic experimental variability.

    Science.gov (United States)

    David, John M; Knowles, Scott; Lamkin, Donald M; Stout, David B

    2013-11-01

    Individual ventilated cages (IVC) are increasing in popularity. Although mice avoid IVC in preference testing, they show no aversion when provided additional nesting material or the cage is not ventilated. Given the high ventilation rate in IVC, we developed 3 hypotheses: that mice housed in IVC experience more cold stress than do mice housed in static cages; that IVC-induced cold stress affects the results of experiments using mice; and that, when provided shelters, mice behaviorally thermoregulate and thereby rescue the cold-stress effects of IVC. To test these hypotheses, we housed mice in IVC, IVC with shelters, and static cages maintained at 20 to 21 °C. We quantified the cold stress of each housing system on mice by assessing nonshivering thermogenesis and brown adipose vacuolation. To test housing effects in a common, murine model of human disease, we implanted mice with subcutaneous epidermoid carcinoma cells and quantified tumor growth, tumor metabolism, and adrenal weight. Mice housed in IVC had histologic signs of cold stress and significantly higher nonshivering thermogenesis, smaller subcutaneous tumors, lower tumor metabolism, and larger adrenal weights than did mice in static cages. Shelters rescued IVC-induced nonshivering thermogenesis, adrenal enlargement, and phenotype-dependent cold-mediated histologic changes in brown adipose tissue and tumor size. IVC impose chronic cold stress on mice, alter experimental results, and are a source of systemic confounders throughout rodent-dependent research. Allowing mice to exhibit behavioral thermoregulation through seeking shelter markedly rescues the experiment-altering effects of housing-imposed cold stress, improves physiologic uniformity, and increases experimental reproducibility across housing systems.

  1. Residual stresses and deformation in dissimilar girth welds: numerical simulations and experimental verifications

    Energy Technology Data Exchange (ETDEWEB)

    Pasquale, P.; Burget, W.; Pfeiffer, W. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2001-03-01

    Weld fabrication of dissimilar girth welds made of the austenitic steel X3 CrNiMoN 17-13, the ferritic 9% Cr-steel X10 CrMoVNb 9-1 and a Ni-weld metal was simulated numerically based on the application of the program system SYSWELD+. A three-dimensional (3D) and an axisymmetrical finite element model of the girth weld were established. According to the real dissimilar weld the model is divided into three different material zones, the austenitic, the ferritic and the Ni-weld metal zone neglecting the heat-affected zone in the ferritic base metal. The results obtained in this study are presented in terms of temperature distributions during welding and just after welding. The residual stresses calculated for the dissimilar girth welds are shown both for the axial and the circumferential orientations. The calculated residual stress distributions are compared to residual stresses measured by X-ray diffraction. It is shown that the calculated residual stresses are in good agreement with the residual stresses determined experimentally. Residual stress distributions in dissimilar girth welds are discussed on the basis of variable weld fabrication conditions and different boundary conditions selected for the numerical calculations. (orig.)

  2. Experimental diabetes in rats causes hippocampal dendritic and synaptic reorganization and increased glucocorticoid reactivity to stress

    Science.gov (United States)

    María Magariños, Ana; McEwen, Bruce S.

    2000-09-01

    We report that 9 d of uncontrolled experimental diabetes induced by streptozotocin (STZ) in rats is an endogenous chronic stressor that produces retraction and simplification of apical dendrites of hippocampal CA3 pyramidal neurons, an effect also observed in nondiabetic rats after 21 d of repeated restraint stress or chronic corticosterone (Cort) treatment. Diabetes also induces morphological changes in the presynaptic mossy fiber terminals (MFT) that form excitatory synaptic contacts with the proximal CA3 apical dendrites. One effect, synaptic vesicle depletion, occurs in diabetes as well as after repeated stress and Cort treatment. However, diabetes produced other MFT structural changes that differ qualitatively and quantitatively from other treatments. Furthermore, whereas 7 d of repeated stress was insufficient to produce dendritic or synaptic remodeling in nondiabetic rats, it potentiated both dendritic atrophy and MFT synaptic vesicle depletion in STZ rats. These changes occurred in concert with adrenal hypertrophy and elevated basal Cort release as well as hypersensitivity and defective shutoff of Cort secretion after stress. Thus, as an endogenous stressor, STZ diabetes not only accelerates the effects of exogenous stress to alter hippocampal morphology; it also produces structural changes that overlap only partially with those produced by stress and Cort in the nondiabetic state.

  3. Phosphoproteomic Analyses Reveal Early Signaling Events in the Osmotic Stress Response1[W][OPEN

    Science.gov (United States)

    E. Stecker, Kelly; Minkoff, Benjamin B.; Sussman, Michael R.

    2014-01-01

    Elucidating how plants sense and respond to water loss is important for identifying genetic and chemical interventions that may help sustain crop yields in water-limiting environments. Currently, the molecular mechanisms involved in the initial perception and response to dehydration are not well understood. Modern mass spectrometric methods for quantifying changes in the phosphoproteome provide an opportunity to identify key phosphorylation events involved in this process. Here, we have used both untargeted and targeted isotope-assisted mass spectrometric methods of phosphopeptide quantitation to characterize proteins in Arabidopsis (Arabidopsis thaliana) whose degree of phosphorylation is rapidly altered by hyperosmotic treatment. Thus, protein phosphorylation events responsive to 5 min of 0.3 m mannitol treatment were first identified using 15N metabolic labeling and untargeted mass spectrometry with a high-resolution ion-trap instrument. The results from these discovery experiments were then validated using targeted Selected Reaction Monitoring mass spectrometry with a triple quadrupole. Targeted Selected Reaction Monitoring experiments were conducted with plants treated under nine different environmental perturbations to determine whether the phosphorylation changes were specific for osmosignaling or involved cross talk with other signaling pathways. The results indicate that regulatory proteins such as members of the mitogen-activated protein kinase family are specifically phosphorylated in response to osmotic stress. Proteins involved in 5′ messenger RNA decapping and phosphatidylinositol 3,5-bisphosphate synthesis were also identified as targets of dehydration-induced phosphoregulation. The results of these experiments demonstrate the utility of targeted phosphoproteomic analysis in understanding protein regulation networks and provide new insight into cellular processes involved in the osmotic stress response. PMID:24808101

  4. Experimental and numerical analyses of the hydrodynamic performance of propeller boss cap fins in a propeller-rudder system

    Directory of Open Access Journals (Sweden)

    Yu Sun

    2016-01-01

    Full Text Available This paper presents the simulated and experimental results of propeller-rudder systems with propeller boss cap fins (PBCFs and analyzes the hydrodynamic performance of PBCFs in propeller-rudder systems. The purpose is to study the impact of PBCFs on the hydrodynamic performance of rudders. Hydrodynamic experiments were carried out on propeller-rudder systems with PBCFs in a cavitation tunnel. The experimental energy-saving effect of the PBCF without a rudder was 1.47% at the design advance coefficient J = 0.8. The numerical simulation was based on the Navier–Stokes equations solved with a sliding mesh and the SST (Shear Stress Transfer k-ω turbulence model. After the grid independence analysis, the flow fields of an open-water propeller with and without a PBCF were compared, then the efficiencies of the propulsion systems including different rudders and the thrust coefficient Kr of rudders were analyzed. The results indicate that the installation of a PBCF increases the resistance of the rudder, which results in a reduction in the energy-saving effect of the PBCF. At the design advance coefficient, the energy-saving effect of the PBCF with an ordinary rudder and a twisted rudder decreases from 1.47% to 1.08% and 1.16%, respectively; thus, it is important to factor in the rudder of a propulsion system when evaluating the energy-saving effects of PBCFs .

  5. Temperature-induced stresses in vacuum glazing: modelling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Simko, T.M.; Collins, R.E. [University of Sydney (Australia). School of Physics; Fischer-Cripps, A.C. [University of Technology, Sydney (Australia). Dept. of Applied Physics

    1998-07-01

    A temperature difference across a sample of vacuum glazing causes differential expansion of one glass sheet relative to the other. In vacuum glazing with a fused edge seal, this results in tensile and compressive stresses in the glass sheets, and bending of the structure. The physical origins of these stresses and deflections are discussed, and a finite element model is used to determine their magnitude. The model has been validated by comparison with experimental data for a well-characterised sample of vacuum glazing under accurately defined external conditions. Modelling data are presented for two glazing designs which have properties that are characteristic of the extremes of performance of this type of glazing. It is shown that mechanical edge constraints can profoundly alter the spatial distribution of stresses in the glazing. (author)

  6. Antistressor activity of Ocimum sanctum (Tulsi) against experimentally induced oxidative stress in rabbits.

    Science.gov (United States)

    Jyoti, S; Satendra, S; Sushma, S; Anjana, T; Shashi, S

    2007-01-01

    Fresh leaves of Ocimum sanctum (O. sanctum) were evaluated for antistress activity against experimentally induced oxidative stress in albino rabbits. Animals of the test group received supplementation of 2 g fresh leaves of O. sanctum per rabbit for 30 days. Anemic hypoxia was induced chemically by injecting the rabbits with 15 mg sodium nitrite per 100 g body weight intraperitoneally. Results indicated that O. sanctum administration blunted the changes in cardiorespiratory (BP, HR, RR) parameters in response to stress. A significant (p sanctum leaves. Significant increase (p sanctum. Oxidative stress led to a lesser depletion of reduced glutathione (28.80%) and plasma superoxide dismutase (23.04%) in O. sanctum-treated rabbits. The results of this study suggest that the potential antistressor activity of O. sanctum is partly attributable to its antioxidant properties.

  7. Biochemical and proteomic analyses of the physiological response induced by individual housing in gilts provide new potential stress markers.

    Science.gov (United States)

    Marco-Ramell, Anna; Arroyo, Laura; Peña, Raquel; Pato, Raquel; Saco, Yolanda; Fraile, Lorenzo; Bendixen, Emøke; Bassols, Anna

    2016-11-25

    The objective assessment of animal stress and welfare requires proper laboratory biomarkers. In this work, we have analyzed the changes in serum composition in gilts after switching their housing, from pen to individual stalls, which is generally accepted to cause animal discomfort. Blood and saliva samples were collected a day before and up to four days after changing the housing system. Biochemical analyses showed adaptive changes in lipid and protein metabolism after the housing switch, whereas cortisol and muscular markers showed a large variability between animals. 2D-DIGE and iTRAQ proteomic approaches revealed variations in serum protein composition after changing housing and diet of gilts. Both techniques showed alterations in two main homeostatic mechanisms: the innate immune and redox systems. The acute phase proteins haptoglobin, apolipoprotein A-I and α1-antichymotrypsin 3, and the antioxidant enzyme peroxiredoxin 2 were found differentially expressed by 2D-DIGE. Other proteins related to the innate immune system, including lactotransferrin, protegrin 3 and galectin 1 were also identified by iTRAQ, as well as oxidative stress enzymes such as peroxiredoxin 2 and glutathione peroxidase 3. Proteomics also revealed the decrease of apolipoproteins, and the presence of intracellular proteins in serum, which may indicate physical injury to tissues. Housing of gilts in individual stalls and diet change increase lipid and protein catabolism, oxidative stress, activate the innate immune system and cause a certain degree of tissue damage. We propose that valuable assays for stress assessment in gilts may be based on a score composed by a combination of salivary cortisol, lipid metabolites, innate immunity and oxidative stress markers and intracellular proteins.

  8. Use of homeopathic preparations in experimental studies with abiotically stressed plants.

    Science.gov (United States)

    Jäger, Tim; Scherr, Claudia; Shah, Devika; Majewsky, Vera; Betti, Lucietta; Trebbi, Grazia; Bonamin, Leoni; Simões-Wüst, Ana Paula; Wolf, Ursula; Simon, Meinhard; Heusser, Peter; Baumgartner, Stephan

    2011-10-01

    Experimental research on the effects of homeopathic treatments on impaired plants was last reviewed in 1990. To compile a systematic review of the existing literature on basic research in homeopathy with abiotically stressed plants using predefined criteria. The literature search was carried out on publications that reported experiments on homeopathy using abiotically stressed whole plants, seeds, plant parts and cells from 1920 to 2010. Outcomes had to be measured by established procedures and statistically evaluated. Using of a Manuscript Information Score (MIS) we identified those publications that provided sufficient information for proper interpretation (MIS≥5). A further evaluation was based on the use of adequate controls to investigate specific effects of homeopathic preparations and on the use of systematic negative control experiments. A total of 34 publications with abiotically stressed plants was identified, published between 1965 and 2010. The 34 publications described a total of 37 experimental studies. Twenty-two studies included statistics, 13 had a MIS≥5, 8 were identified with adequate controls and 4 with negative control experiments. Significant and reproducible effects with decimal and centesimal potencies were found, including dilution levels beyond Avogadro's number. One experimental model was independently assessed by another research team and yielded inverted results compared to the original trial. Abiotically stressed plant models seem to be a useful approach to investigate homeopathic basic research questions, but more experimentation and especially more independent replication trials are needed. Systematic negative control experiments should be implemented on a routine basis to exclude false-positive results. Copyright © 2011 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  9. [Experimental verification and prospect on stress effect of Dao-di herbs Scutellaria baicalensis].

    Science.gov (United States)

    Yuan, Yuan; Zhou, Jun-Hui; Huang, Lu-Qi

    2016-01-01

    The stress effect is a characteristic of Dao-di herbs caused by environmental gene expression of medical plants is influenced by environmental changes and finally affects the formation and accumulation of metabolites. Using Scutellaria baicalensis as material, active component of wild type of S. baicalensis from 19 production areas were analysed; It was found that climate change can influence the accumulation of active components. Then, S. baicalensis suspension cells was exposed to various environments, and enzyme activity and gene expression were measured, indicating the molecular mechanism of stress effect on S. baicalensis. Hence, we found the prerequisite and method to study the stress effect on Dao-di herbs, and we hope this research can provides some references for another studies of Dao-di herbs. Copyright© by the Chinese Pharmaceutical Association.

  10. EXPERIMENTAL SETUP FOR MODELING AND STUDY OF COMPLEX STRESS STATE IN FERROMAGNETIC MATERIALS

    Directory of Open Access Journals (Sweden)

    V. N. Busko

    2016-01-01

    Full Text Available Most of the load experiencing parts operate in a complex state of stress (СSS. The article describes the device layout diagram for modeling a СSS in a ferromagnetic material and the development of monitoring methods. The principle of operation of the device is based on the joint action at a sample of longitudinal extension and lateral bending. The article describes the methods of creating a СSS and materials research using the method of the Barkhausen effect in static and dynamic loading conditions. The article presents the functioning of the algorithm and device operating principle. The article also shows the diagram for modeling a СSS in a steel sample. In this work, are the construction and operation of the device described in detail. This device differs from simple industrial test equipment by small weight, size and cost. The paper presents experimental examples of the influence of the simple forms of the state of stress (longitudinal stretching or lateral bending and a CSS on the intensity of the magnetic noise in two samples of structural steel. The study established that the total value of the magnetic noise in complex stress state of the sample caused by the forces of simultaneously stretching and bending load, is approximately equal to the algebraic sum of magnetic noise values for each simple type of stress. The linearity of the intensity of the magnetic noise versus axial tensile stress is observed in a range of 0 to ≈ +300 MPa, flexural tensile stresses – of 0 to ≈ +500 MPa, the total stresses – to ≈ 100–110 MPa. The obtained results confirmed the efficiency and effectiveness of the device. The article shows that the magnetic noise is affected not only by the magnitude of the tensile stress of the axial force or tensile stresses in bending or full stresses, but also by the steel grade, the physical and mechanical properties of the material under test. The sensitivity of the magnetic noise to the combined action of the

  11. Rearing effect of biofloc on antioxidant and antimicrobial transcriptional response in Litopenaeus stylirostris shrimp facing an experimental sub-lethal hydrogen peroxide stress.

    Science.gov (United States)

    Cardona, Emilie; Saulnier, Denis; Lorgeoux, Bénédicte; Chim, Liet; Gueguen, Yannick

    2015-08-01

    This study compares the antioxidant and antimicrobial transcriptional expression of blue shrimps reared according to two different systems, BioFloc Technology (BFT) and Clear sea Water (CW) and their differential responses when facing an experimental sublethal hydrogen peroxide stress. After 30 days of rearing, juvenile shrimps were exposed to H2O2 stress at a concentration of 30 ppm during 6 h. The oxidative stress caused by H2O2 was examined in the digestive glands of the shrimp, in which antioxidant enzyme (AOE) and antimicrobial peptide (AMP) gene expression were analysed by quantitative real-time PCR. Results showed that rearing conditions did not affect the expression of genes encoding AOEs or AMPs. However, H2O2 stress induced a differential response in expression between shrimps from the two rearing treatments (BFT and CW). Comparative analysis of the expression profiles indicates that catalase transcripts were significantly upregulated by H2O2 stress for BFT shrimps while no change was observed for CW shrimps. In contrast, H2O2 caused down-regulation of superoxide dismutase and glutathione transferase transcripts and of the three AMP transcripts studied (penaeidin 2 and 3, and crustin) for CW shrimps, while no effect was observed on BFT shrimp transcript levels. These results suggested that BFT shrimps maintained antioxidant and AMP responses after stress and therefore can effectively protect their cells against oxidative stress, while CW shrimp immune competence seems to decrease after stress. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Patterns of attention and experiences of post-traumatic stress symptoms following childbirth: an experimental study.

    Science.gov (United States)

    Dale-Hewitt, Vanessa; Slade, Pauline; Wright, Ingram; Cree, Michelle; Tully, Chris

    2012-08-01

    Childbirth for some women can be experienced as a traumatic event whereby it is appraised as threatening to life and associated with feelings of fear, helplessness or horror. These women may develop symptoms consistent with post-traumatic stress disorder or its sub-clinical symptoms (post-traumatic stress, PTS). Cognitive processes such as attentional biases have been identified in individuals with PTS exposed to other traumatic events. This study used an experimental design (the modified Stroop task) to investigate the relationship between attentional biases and PTS symptoms in 50 women who experienced their labour and delivery as stressful and responded with fear, helplessness and horror. Attentional biases away from childbirth words were significantly associated with both symptoms of post-traumatic stress and more negative experiences of childbirth. A negative experience was also associated with more severe symptoms of PTS. Positive experiences were unassociated with attentional biases or symptoms. Post-traumatic stress responses, in this population, may be associated with avoidance, and through influencing cognitive processing, acting as a maintaining factor of distress.

  13. Stress-induced allodynia--evidence of increased pain sensitivity in healthy humans and patients with chronic pain after experimentally induced psychosocial stress.

    Directory of Open Access Journals (Sweden)

    Benjamin Crettaz

    Full Text Available BACKGROUND: Experimental stress has been shown to have analgesic as well as allodynic effect in animals. Despite the obvious negative influence of stress in clinical pain conditions, stress-induced alteration of pain sensitivity has not been tested in humans so far. Therefore, we tested changes of pain sensitivity using an experimental stressor in ten female healthy subjects and 13 female patients with fibromyalgia. METHODS: Multiple sensory aspects of pain were evaluated in all participants with the help of the quantitative sensory testing protocol before (60 min and after (10 and 90 min inducing psychological stress with a standardized psychosocial stress test ("Trier Social Stress Test". RESULTS: Both healthy subjects and patients with fibromyalgia showed stress-induced enhancement of pain sensitivity in response to thermal stimuli. However, only patients showed increased sensitivity in response to pressure pain. CONCLUSIONS: Our results provide evidence for stress-induced allodynia/hyperalgesia in humans for the first time and suggest differential underlying mechanisms determining response to stressors in healthy subjects and patients suffering from chronic pain. Possible mechanisms of the interplay of stress and mediating factors (e.g. cytokines, cortisol on pain sensitivity are mentioned. Future studies should help understand better how stress impacts on chronic pain conditions.

  14. Assessment of urban thermal stress by UTCI – experimental and modelling studies: an example from Poland

    Directory of Open Access Journals (Sweden)

    Błażejczyk, Krzysztof

    2014-09-01

    Full Text Available The paper presents a new approach to the study of the spatial variability of heat stress in urban areas. The Universal Thermal Climate Index UTCI was applied for this purpose. The spatial variability of UTCI at the local scale was studied using examples of urban areas with different sizes and geographical locations. The experimental research on urban heat stress was conducted in Warsaw. The research covers both differences between UTCI in urban to rural areas as well as the variation of heat stress within small residential districts in Warsaw. We found a very large and significant heat stress gradient between downtown Warsaw and rural stations. Spatial variability of UTCI was also observed in microclimate research. A modelling approach was presented based on examples from Warsaw, a city with a population of almost 2 million, as well as examples from several spa towns with populations of up to 40,000 located in various parts of Poland. GIS analysis (ArcGIS for Desktop and IDRISI was applied for this purpose.

  15. An experimental analysis to monitor and manage stress among engineering students using Galvanic Skin Response meter.

    Science.gov (United States)

    Joshi, Anurag; Kiran, Ravi; Sah, Ash Narayan

    2017-01-01

    This paper studies the impact of musical religious songs (hymns) for managing stress of Indian Engineering students through Galvanic Skin Response (GSR). The objective of the paper is to find out, whether listening to hymns is able to reduce the value of GSR. Sample students were selected through initial screening and the students who reported high mental stress during the interview were selected for the main drills. All the readings were taken using a GSR meter. Statistical t-test was used for the purpose of hypothesis testing. The study examines the relation between GSR and stress. The results indicated that listening to hymns had a significant effect on the value of GSR. The results highlight that GSR decreased at t = 300 seconds for the experimental group, who listened to hymns, as compared to control group (not exposed to the same). It is recommended that, this amazingly effortless and yet highly efficient traditional technique of listening to hymns be made a part of student's routine curriculum. The paper aims at spreading awareness of listening to hymns as one of the modes of Stress Management amongst Indian Engineering Students.

  16. Experimental And Theoretical Stress Analysis For Composite Plate Under Combined Load

    Directory of Open Access Journals (Sweden)

    Emad Qasim Hussein

    2017-12-01

    Full Text Available The combined effects of thermal and mechanical loadings on the distribution of stress-strain for E-glass fiber /polyester composite plates are investigated experimentally and numerically. The experimental work has been carried out by applying to a uniform temperature and tensile load on the composite plate inside the furnace and the deformation of plate measured by a dial gauge. Two parameter studies, the fiber volume fraction and fiber orientation on the stress-strain for plates subjected to identical mechanical and temperature gradient. The results presented showed that, the maximum absolute of total strain in longitudinal direction occurred at 50 N tension load and fiber angle 60º, while the minimum absolute values of it occurred at 15 N tension loads and fiber angle 0º. However the maximum absolute of total strain in transverse direction occurred at 15N tension load and fiber angle 0º, while the minimum absolute values of it are obtained at 50 N tension loads and fiber angle 60º. Also, the total strain in longitudinal and transverse direction decrease with increasing the fiber volume fraction. Comparison of the results in the experimental test with the numerical analysis of the total strain and evaluated the agreement between the two methods used, the maximum discrepancywas 20%.

  17. Experimental investigation of stress-strain conditions in punching zone of flat slabs

    Directory of Open Access Journals (Sweden)

    Filatov Valery

    2017-01-01

    Full Text Available The technique and results of experimental study on the test specimens of the stress-strain condition of flat reinforced concrete slabs of a girderless framework at punching by columns of square and rectangular section are presented. The punching shear strength of slabs at rectangular columns can be lower than at square columns with a similar length of the control perimeter. The research of influence of a form of a column cross-section on the stress-strain condition of a reinforced concrete slab in a punching zone is conducted. The comparative analysis of distribution of concrete and reinforcement deformations of reinforced concrete slabs on column perimeter depending on a ratio of the sides of cross section is made. The results of the research of сracking in a zone of punching of reinforced concrete slabs are presented here. Results of the conducted research allow expanding the base of experimental data of the considered subject and promoting improvement of modern positions in the theory of power resistance of reinforced concrete. New experimental data received in the research corresponded with the earlier offered hypothesis that in a slab there is a zone of the constrained deformation located along the perimeter around the rectangular column.

  18. Nitrogen diffusion and nitrogen depth profiles in expanded austenite: experimental assessment, numerical simulation and role of stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2008-01-01

    The present paper addresses the experimental assessment of the concentration dependent nitrogen diffusion coefficient in stress free expanded austenite foils from thermogravimetry, the numerical simulation of nitrogen concentration depth profiles on growth of expanded austenite into stainless ste...

  19. The role of flaxseed and vitamin E on oxidative stress in prepubertal rats with experimental varicocele: An experimental study

    Directory of Open Access Journals (Sweden)

    Shahla Sohrabipour

    2013-06-01

    Full Text Available Background: Prepubertal varicocele has the most devastating effects on the testes. Oxidative stress is the major cause leading to infertility in varicocele. The antioxidant properties of Flaxseed (FS treatment in some oxidative diseases have been reported. Objective: This study aimed to evaluate the antioxidant effect of FS in prepubertal rats with experimental varicocele. Materials and Methods: Forty two male prepubertal rats were divided into 6 groups: the varicocele group were either fed with 10% FS, or with regular diet, or with Vit E, the group with sham operation fed with 10% FS, or had regular diet, and control rats who had not been operated but received regular diet. Varicocele was created by Koksal method. After 6 weeks sperm superoxide anion and H2O2 were evaluated by flowcytometery. Semen total antioxidant capacity (TAC by Koracevic method and testes malondialdehyde (MDA by thiobarbituric acid with spectrophotometry was measured. Results: While superoxide anion and H2O2 were significantly higher in varicocele grop with regular diet (p=0.0001, FS significantly decreased the previously-mentioned parameters (p=0.0001. There were no significant differences for seminal TAC between 6 groups (p=0.07. Left testicular MDA concentration were lower in varicocele or group that were fed with 10% FS compared with other groups (p=0.001. Conclusion: Reactive oxygen species (ROS may cause sperm oxidative damage. FS as a fat soluble antioxidant can scavenge intracellular ROS production in varicocele.

  20. Systems Genetic Analyses Highlight a TGFβ-FOXO3 Dependent Striatal Astrocyte Network Conserved across Species and Associated with Stress, Sleep, and Huntington's Disease.

    Directory of Open Access Journals (Sweden)

    Joseph R Scarpa

    2016-07-01

    Full Text Available Recent systems-based analyses have demonstrated that sleep and stress traits emerge from shared genetic and transcriptional networks, and clinical work has elucidated the emergence of sleep dysfunction and stress susceptibility as early symptoms of Huntington's disease. Understanding the biological bases of these early non-motor symptoms may reveal therapeutic targets that prevent disease onset or slow disease progression, but the molecular mechanisms underlying this complex clinical presentation remain largely unknown. In the present work, we specifically examine the relationship between these psychiatric traits and Huntington's disease (HD by identifying striatal transcriptional networks shared by HD, stress, and sleep phenotypes. First, we utilize a systems-based approach to examine a large publicly available human transcriptomic dataset for HD (GSE3790 from GEO in a novel way. We use weighted gene coexpression network analysis and differential connectivity analyses to identify transcriptional networks dysregulated in HD, and we use an unbiased ranking scheme that leverages both gene- and network-level information to identify a novel astrocyte-specific network as most relevant to HD caudate. We validate this result in an independent HD cohort. Next, we computationally predict FOXO3 as a regulator of this network, and use multiple publicly available in vitro and in vivo experimental datasets to validate that this astrocyte HD network is downstream of a signaling pathway important in adult neurogenesis (TGFβ-FOXO3. We also map this HD-relevant caudate subnetwork to striatal transcriptional networks in a large (n = 100 chronically stressed (B6xA/JF2 mouse population that has been extensively phenotyped (328 stress- and sleep-related measurements, and we show that this striatal astrocyte network is correlated to sleep and stress traits, many of which are known to be altered in HD cohorts. We identify causal regulators of this network through

  1. Computational and Experimental Models of Cancer Cell Response to Fluid Shear Stress

    Directory of Open Access Journals (Sweden)

    Michael J. Mitchell

    2013-03-01

    Full Text Available It has become evident that mechanical forces play a key role in cancer metastasis, a complex series of steps that is responsible for the majority of cancer-related deaths. One such force is fluid shear stress, exerted on circulating tumor cells (CTCs by blood flow in the vascular microenvironment, and also on tumor cells exposed to slow interstitial flows in the tumor microenvironment. Computational and experimental models have the potential to elucidate metastatic cell behavior exposed to such forces. Here, we review the fluid-generated forces that tumor cells are exposed to in the vascular and tumor microenvironments, and discuss recent computational and experimental models that have revealed mechanotransduction phenomena that may play a role in the metastatic process.

  2. Three-dimensional stress analysis of O-ring under uniform squeeze and internal pressure by photoelastic experimental hybrid method

    Science.gov (United States)

    Hawong, J. S.; Nam, J. H.; Liu, Y.; Shin, D. C.

    2010-03-01

    Until now, it is known that stresses on the plane (y-z plane) perpendicular to the circumferential direction (x axis) of Oring exist and stresses on the plane (x-y plane and x-z plane) parallel to the circumferential direction of O-ring does not exist when O-ring is under uniform squeeze rate and internal pressure. But it was known that stresses of x-y plane and xz plane of O-ring under uniform squeeze and internal pressure were existed by this research. To analyze 3 dimensional stress distributions of O-ring under those loadings, stress distributions of every plane should be analyzed. Therefore, photoelastic experimental hybrid method for 3 dimensional stress distributions of O-ring under uniform squeeze and internal pressure were developed in this research. Photoelastic experimental procedures for 3 dimensional stress distributions of O-ring under those loadings were introduced. Stress distributions of O-ring under those loadings were analyzed by photoelastic experimental hybrid method developed in this research. Von Mises equivalent stresses at arbitrary point of O-ring under those loadings were analyzed.

  3. Experimental studies the evolution of stress-strain state in structured rock specimens under uniaxial loading

    Science.gov (United States)

    Oparin, Viktor; Tsoy, Pavel; Usoltseva, Olga; Semenov, Vladimir

    2014-05-01

    The aim of this study was to analyze distribution and development of stress-stress state in structured rock specimens subject to uniaxial loading to failure. Specific attention was paid to possible oscillating motion of structural elements of the rock specimens under constraints (pre-set stresses at the boundaries of the specimens) and the kinetic energy fractals. The detailed studies into the micro-level stress-strain state distribution and propagation over acting faces of rock specimens subject to uniaxial loading until failure, using automated digital speckle photography analyzer ALMEC-tv, have shown that: • under uniaxial stiff loading of prismatic sandstone, marble and sylvinite specimens on the Instron-8802 servohydraulic testing machine at the mobile grip displacement rate 0.02-0.2 mm/min, at a certain level of stressing, low-frequency micro-deformation processes originate in the specimens due to slow (quasi-static) force; • the amplitude of that deformation-wave processes greatly depends on the micro-loading stage: — at the elastic deformation stage, under the specimen stress lower than half ultimate strength of the specimen, there are no oscillations of microstrains; —at the nonlinearly elastic deformation stage, under stress varied from 0.5 to 1 ultimate strength of the specimens, the amplitudes of microstrains grow, including the descending stage 3; the oscillation frequency f=0.5-4 Hz; —at the residual strength stage, the amplitudes of the microstrains drop abruptly (3-5 times) as against stages 2 and 3; • in the elements of the scanned specimen surface in the region with the incipient crack, the microstrain rate amplitudes are a few times higher than in the undamged surface region of the same specimen. Sometimes, deformation rate greatly grows with increase in the load. The authors have used the energy scanning function of the deformation-wave processes in processing experimental speckle-photography data on the surface of the test specimen

  4. Tic frequency decreases during short-term psychosocial stress – an experimental study on children with tic disorders

    Directory of Open Access Journals (Sweden)

    Judith Katharina Buse

    2016-05-01

    Full Text Available It has been suggested that psychosocial stress influences situational fluctuations of tic frequency. However, evidence from experimental studies is lacking. The current study investigated the effects of the Trier Social Stress Test on tic frequency in 31 children and adolescents with tic disorders. A relaxation and a concentration situation served as control conditions. Patients were either asked to suppress their tics, or to tic freely. Physiological measures of stress were measured throughout the experiment. The Trier Social Stress Test elicited a clear stress response with elevated levels of saliva cortisol, increased heart rate, and a larger number of skin conductance responses. During relaxation and concentration the instruction to suppress tics reduced the number of tics, while during stress the number of tics was low, regardless of the given instruction. Our study suggests that stress might result in a situational decrease of tic frequency.

  5. Tectonic stresses in the lithosphere: constraints provided by the experimental deformation of rocks.

    Science.gov (United States)

    Kirby, S.H.

    1980-01-01

    The strengths of rocks clearly place an upper limit on the stress that can be sustained by the upper half of the lithosphere. Laboratory data on rock rheology are generally lacking at intermediate temperatures and pressures on the important rock types expected in the lithosphere, so a definitive accounting of the strength distribution with depth in the upper lithosphere is presently unattainable. Analogies are drawn between the fragmentary strength data on slicates at intermediate temperature and the more extensive experimental data on marble and limestone, and several tentative conclusions are drawn: First, brittle processes, such as faulting and cataclasis, are expected to control rock strength at low pressures and temperatures. The strengths associated with these brittle mechanisms increase rapidly with increasing effective pressure and are relatively insensitive to temperature and strain rate. Second, the transitions between brittle and ductile processes occur at critical values of the least principal stress sigma3. I suggest that the concept of the deformation mechanism map of Ashby (1972) be extended to brittle-ductile transitions by normalizing the applied differential stress sigma by sigma3, i.e., the transitions occur at critical values of sigma/sigma3. -from Author

  6. Experimental Colitis Is Attenuated by Cardioprotective Diet Supplementation That Reduces Oxidative Stress, Inflammation, and Mucosal Damage

    Directory of Open Access Journals (Sweden)

    Hilda Vargas Robles

    2016-01-01

    Full Text Available Inflammatory bowel diseases (IBD such as ulcerative colitis (UC and Crohn’s disease (CD are multifactorial, relapsing disorders of the gastrointestinal tract. However, the etiology is still poorly understood but involves altered immune responses, epithelial dysfunction, environmental factors, and nutrition. Recently, we have shown that the diet supplement corabion has cardioprotective effects due to reduction of oxidative stress and inflammation. Since oxidative stress and inflammation are also prominent risk factors in IBD, we speculated that corabion also has beneficial effects on experimental colitis. Colitis was induced in male mice by administration of 3.5% (w/v dextran sulfate sodium (DSS in drinking water for a period of 3 or 7 days with or without daily gavage feeding of corabion consisting of vitamin C, vitamin E, L-arginine, and eicosapentaenoic and docosahexaenoic acid. We found that corabion administration attenuated DSS-induced colon shortening, tissue damage, and disease activity index during the onset of colitis. Mechanistically, these effects could be explained by reduced neutrophil recruitment, oxidative stress, production of proinflammatory cytokines, and internalization of the junctional proteins ZO-1 and E-cadherin leading to less edema formation. Thus, corabion may be a useful diet supplement for the management of chronic inflammatory intestinal disorders such as IBD.

  7. Experimental Colitis Is Attenuated by Cardioprotective Diet Supplementation That Reduces Oxidative Stress, Inflammation, and Mucosal Damage.

    Science.gov (United States)

    Vargas Robles, Hilda; Citalán Madrid, Alí Francisco; García Ponce, Alexander; Silva Olivares, Angelica; Shibayama, Mineko; Betanzos, Abigail; Del Valle Mondragón, Leonardo; Nava, Porfirio; Schnoor, Michael

    2016-01-01

    Inflammatory bowel diseases (IBD) such as ulcerative colitis (UC) and Crohn's disease (CD) are multifactorial, relapsing disorders of the gastrointestinal tract. However, the etiology is still poorly understood but involves altered immune responses, epithelial dysfunction, environmental factors, and nutrition. Recently, we have shown that the diet supplement corabion has cardioprotective effects due to reduction of oxidative stress and inflammation. Since oxidative stress and inflammation are also prominent risk factors in IBD, we speculated that corabion also has beneficial effects on experimental colitis. Colitis was induced in male mice by administration of 3.5% (w/v) dextran sulfate sodium (DSS) in drinking water for a period of 3 or 7 days with or without daily gavage feeding of corabion consisting of vitamin C, vitamin E, L-arginine, and eicosapentaenoic and docosahexaenoic acid. We found that corabion administration attenuated DSS-induced colon shortening, tissue damage, and disease activity index during the onset of colitis. Mechanistically, these effects could be explained by reduced neutrophil recruitment, oxidative stress, production of proinflammatory cytokines, and internalization of the junctional proteins ZO-1 and E-cadherin leading to less edema formation. Thus, corabion may be a useful diet supplement for the management of chronic inflammatory intestinal disorders such as IBD.

  8. Experimental and CFD Simulation Studies of Wall Shear Stress for Different Impeller Configurations and MBR Activated Sludge

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Chan, C.C.V.; Bentzen, Thomas Ruby

    2012-01-01

    in an MBR. Nevertheless, proper experimental validation is required to validate CFD simulation. In this work experimental measurements of shear stress induced by impellers at a membrane surface were made with an electrochemical approach and the results were used to validate CFD simulations. As good results...... appealing for full-scale applications. It has been widely demonstrated that the filtration performances in MBRs can be improved by understanding the shear stress over the membrane surface. Modern tools such as Computational Fluid Dynamics (CFD) can be used to diagnose and understand the shear stress...... were attained with the CFD model (

  9. Stress state dependence of in-reactor creep and swelling. Part 2: Experimental results

    Science.gov (United States)

    Hall, M. M., Jr.; Flinn, J. E.

    2010-01-01

    Irradiation creep constitutive equations, which were developed in Part I, are used here to analyze in-reactor creep and swelling data obtained ca. 1977-1979 as part of the US breeder reactor program. The equations were developed according to the principles of incremental continuum plasticity for the purpose of analyzing data obtained from a novel irradiation experiment that was conducted, in part, using Type 304 stainless steel that had been previously irradiated to significant levels of void swelling. Analyses of these data support an earlier observation that all stress states, whether tensile, compressive, shear or mixed, can affect both void swelling and interactions between irradiation creep and swelling. The data were obtained using a set of five unique multiaxial creep-test specimens that were designed and used for the first time in this study. The data analyses demonstrate that the constitutive equations derived in Part I provide an excellent phenomenological representation of the interactive creep and swelling phenomena. These equations provide nuclear power reactor designers and analysts with a first-of-its-kind structural analysis tool for evaluating irradiation damage-dependent distortion of complex structural components having gradients in neutron damage rate, temperature and stress state.

  10. Experimental model to evaluate in vivo and in vitro cartilage MR imaging by means of histological analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bittersohl, B. [Department of Orthopedic Surgery, University of Berne, Inselspital, 3010 Bern (Switzerland); Mamisch, T.C. [Department of Orthopedic Surgery, University of Berne, Inselspital, 3010 Bern (Switzerland)], E-mail: mamisch@bwh.harvard.edu; Welsch, G.H. [Department of Trauma Surgery, University of Erlangen (Germany); Stratmann, J.; Forst, R. [Department of Orthopedic Surgery, University of Erlangen (Germany); Swoboda, B. [Department of Orthopedic Rheumatology, University of Erlangen (Germany); Bautz, W. [Department of Diagnostic Radiology, University of Erlangen (Germany); Rechenberg, B. von [Musculoskeletal Research Unit (MSRU), University of Zurich (Switzerland); Cavallaro, A. [Department of Diagnostic Radiology, University of Erlangen (Germany)

    2009-06-15

    Objectives: Implementation of an experimental model to compare cartilage MR imaging by means of histological analyses. Material and methods: MRI was obtained from 4 patients expecting total knee replacement at 1.5 and/or 3 T prior surgery. The timeframe between pre-op MRI and knee replacement was within two days. Resected cartilage-bone samples were tagged with Ethi-pins to reproduce the histological cutting course. Pre-operative scanning at 1.5 T included following parameters for fast low angle shot (FLASH: TR/TE/FA = 33 ms/6 ms/30 deg., BW = 110 kHz, 120 mm x 120 mm FOV, 256 x 256 matrix, 0.65 mm slice-thickness) and double echo steady state (DESS: TR/TE/FA = 23.7 ms/6.9 ms/40 deg., BW = 130 kHz, 120 x 120 mm FOV, 256 x 256 matrix, 0.65 mm slice-thickness). At 3 T, scan parameters were: FLASH (TR/TE/FA = 12.2 ms/5.1 ms/10 deg., BW = 130 kHz, 170 x 170 mm FOV, 320 x 320, 0.5 mm slice-thickness) and DESS (TR/TE/FA = 15.6 ms/4.5 ms/25 deg., BW = 200 kHz, 135 mm x 150 mm FOV, 288 x 320 matrix, 0.5 mm slice-thickness). Imaging of the specimens was done the same day at 1.5 T. MRI (Noyes) and histological (Mankin) score scales were correlated using the paired t-test. Sensitivity and specificity for the detection of different grades of cartilage degeneration were assessed. Inter-reader and intra-reader reliability was determined using Kappa analysis. Results: Low correlation (sensitivity, specificity) was found for both sequences in normal to mild Mankin grades. Only moderate to severe changes were diagnosed with higher significance and specificity. The use of higher field-strengths was advantageous for both protocols with sensitivity values ranging from 13.6% to 93.3% (FLASH) and 20.5% to 96.2% (DESS). Kappa values ranged from 0.488 to 0.944. Conclusions: Correlating MR images with continuous histological slices was feasible by using three-dimensional imaging, multi-planar-reformat and marker pins. The capability of diagnosing early cartilage changes with high accuracy

  11. Effects of short duration stress management training on self-perceived depression, anxiety and stress in male automotive assembly workers: a quasi-experimental study

    Directory of Open Access Journals (Sweden)

    Naing L

    2008-11-01

    Full Text Available Abstract To examine the effects of short duration stress management training (SMT on self-perceived depression, anxiety and stress in male automotive assembly workers, 118 male automotive workers from Pekan, Pahang (n = 60, mean age = 40.0 years, SD = 6.67 and Kota Bharu, Kelantan (n = 58, mean age = 38.1 years, SD = 5.86 were assigned to experimental and control group, respectively. A SMT program consisting of aerobic exercise, stress management manual, video session, lecture, question and answer session, and pamphlet and poster session were conducted in the experimental group. A validated short-form Malay version of the Depression Anxiety Stress Scales (DASS-21 were self-administered before and after the intervention program in the experimental and control group and their time and group interaction effects were examined using the repeated measure ANOVA test. Results indicated that the mean (SD scores for DASS-Depression (p = 0.036 and DASS-Anxiety (p = 0.011 were significantly decreased, respectively, after the intervention program in the experimental group as compared to the control group (significant time-group interaction effects. No similar effect was observed for the mean (SD scores for DASS-Stress (p = 0.104. However, the mean (SD scores for subscales of DASS-Depression (Dysphoria, p = 0.01, DASS-Anxiety (Subjective Anxiety, p = 0.007, Situational Anxiety, p = 0.048, and DASS-Stress (Nervous Arousal, p = 0.018, Easily Upset, p = 0.047 showed significant time and group interaction effects. These findings suggest that short duration SMT is effective in reducing some aspects of self-perceived depression, anxiety and stress in male automotive workers.

  12. [THE ALKALOID-FREE FRACTION FROM Galega officinalis EXTRACT PREVENTS OXIDATIVE STRESS UNDER EXPERIMENTAL DIABETES MELLITUS].

    Science.gov (United States)

    Lupak, M I; Khokhla, M R; Hachkova, G Ya; Kanyuka, O P; Klymyshyn, N I; Chajka, Ya P; Skybitska, M I; Sybirna, N O

    2015-01-01

    The effect of alkaloid-free fraction from Galega officinalis extract on the process of formation of reactive oxygen species and indicators of prooxidant-antioxidant balance was investigated in rat peripheral blood under conditions of experimental diabetes mellitus. It was shown that alkaloid-free fraction from Galega officinalis extract prevents oxidative stress development in rats with streptozotocin-induced diabetes, providing antioxidant and antiradical mobilization mechanisms to protect the blood system. In the case of extract application to animals with studied pathology, one can observe a reducing effect of reactive oxygen species generation in leukocytes, inhibition of proteins and lipids oxidative modification processes and increased activity of key enzymes of rat peripheral blood antioxidant system (superoxide dismutase, catalase and glutathione peroxidase). The revealed biological effect could be explained by the presence of biologically active substances with antioxidant properties in the extract composition (phytol and flavonoids).

  13. [Change of blood antioxidant capacity of experimental animals during nutritional correction under oxidative stress].

    Science.gov (United States)

    Basov, A A; Bykov, I M

    2013-01-01

    The effect of nutritional correction (a diet high in foods with antioxidant content) on blood parameters in laboratory animals with metabolic disorders associated with oxidative stress has been studied. In experimental models of laboratory animals (male rabbits weighing 3.5-4.0 kg, n = 40) with purulent septic diseases it has been demonstrated that the use of nutritive correction (replacement of 100 g of the cereal mixture through day on a mixture of cabbage 50 g, carrots 50 g, beet 25 g, apple 25 g, kiwi 10 g and garnet 10 g per 1 rabbit) is not inferior to its efficiency of glutathione use (2 g per day). The use of these antioxidants in laboratory animals significantly reduced the phenomenon of oxidative stress on the 5th day: blood antioxidant capacity significantly increased by 14.9 and 26.6%, and the area of the flash of luminol-dependent H2O2-induced chemiluminescence of blood plasma reduced by 44.2 and 48.6% in the experimental groups receiving respectively nutritive correction and glutathione. The low-molecula level of blood antioxidant capacity was restored and the balance of the activity of superoxide dismutase (decrease) and catalase (increase) was achieved on the 10th day of the experiment. These figures significantly (p < 0.05) differed from than in the group of animals receiving no antioxidant correction. The latter studied parameters of prooxidant-antioxidant system reached values comparable with those in intact animals (n = 10) only on the 30th day, confirming the advisability of appointing a complex antioxidant therapy.

  14. Chronic stress moderates the impact of social exclusion on pain tolerance: an experimental investigation.

    Science.gov (United States)

    Pieritz, Karoline; Schäfer, Sarina J; Strahler, Jana; Rief, Winfried; Euteneuer, Frank

    2017-01-01

    Experiences of social pain due to social exclusion may be processed in similar neural systems that process experiences of physical pain. The present study aimed to extend the findings on social exclusion and pain by examining the impact of social exclusion on an affective (ie, heat pain tolerance) and a sensory component of pain (ie, heat pain intensity). Whether a potential effect may be moderated by chronic life stress, social status, or social sup-port was further examined. A community-based sample of 59 women was studied. Social exclusion and inclusion were experimentally manipulated by using a virtual ball-tossing game called Cyberball in which participants were randomly assigned to either being excluded or being included by two other virtual players. Heat pain tolerance and intensity were assessed before and after the game. Potential psychosocial moderators were assessed via a questionnaire. The main finding of this study is that chronic stress moderates the impact of social exclusion on pain tolerance (psocially excluded participants showed a lower heat pain tolerance than participants who were socially included. Contrary to the authors' hypothesis, pain sensitivity was increased in socially included participants compared with socially excluded participants after the game (psocial exclusion.

  15. Experimental scale model study of cracking in brick masonry under tensile and shear stress

    Directory of Open Access Journals (Sweden)

    Gálvez Ruiz, J. C.

    2008-09-01

    Full Text Available This article discusses the results of research conducted on the failure behaviour of brick masonry under tensile and shear stress. The study was designed to develop test models and generate experimental results able to provide greater insight into tensile and shear stresses cracking in brick masonry. The results of a campaign conducted with two types of specimens are discussed: 1 double-edge notched specimens under non-symmetrical compression stress, and 2 three point bending specimens under nonsymmetrical loading. Tests were run on specimens of similar size (similarity rate 2 and different bed joint orientation to determine how bed joint orientation affects crack propagation. The tests were conducted on scale models (1/4 of a single wythe, stretcher bond brickwork masonry wall one half foot thick.Este artículo presenta los resultados de la investigación realizada sobre el comportamiento en rotura de la fábrica de ladrillo bajo solicitaciones de tracción y cortante. La investigación está encaminada a proporcionar modelos de ensayo y resultados experimentales que permitan conocer mejor los procesos de agrietamiento de la fábrica de ladrillo bajo tensiones normales de tracción y tangenciales. Se presentan los resultados de una campaña experimental desarrollada con dos tipos de probeta: 1 la probeta compacta con doble entalla solicitada a compresión asimétrica, y 2 la probeta de flexión con entalla solicitada bajo carga asimétrica aplicada en tres puntos. Se han ensayado probetas de dos tamaños semejantes (razón de semejanza 2 y varias orientaciones de los tendeles, con el fin de ver cómo afecta la orientación de los tendeles en la propagación de las grietas. Los ensayos se han realizado con probetas a escala 1/4 de un muro de fábrica de ladrillo de una hoja a soga de medio pie de espesor.

  16. Effect of propolis on oxidative stress and histomorphology of liver tissue in experimental obstructive jaundice.

    Science.gov (United States)

    Kismet, K; Sabuncuoglu, M Z; Kilicoglu, S S; Kilicoglu, B; Devrim, E; Erel, S; Sunay, A E; Erdemli, E; Durak, I; Akkus, M A

    2008-01-01

    Propolis is a natural product collected by honey bees from various plant sources. We aimed to determine the possible effects of propolis on oxidative stress and hepatocyte apoptosis in experimental obstructive jaundice. Thirty rats were divided into three groups: group I, sham-operated; group II, ligation and division of the common bile duct (BDL); group III, BDL followed by oral supplementation of propolis in a daily dose of 100 mg/kg. Liver samples were examined under the light microscope and transmission electron microscope. Hepatocyte apoptosis was quantitated using the transferase-mediated uridine nick end labeling (TUNEL) assay. Plasma and liver malondialdehyde (MDA) levels and glutathione peroxidase (GSH-Px) activities were measured. The plasma and liver levels of MDA were significantly lower in the propolis group than in the BDL group (p propolis group than in the BDL group (p 0.05). In the propolis group, the enlargement of hepatocytes, dilatation of canaliculi and the edema regressed. The regenerating and normal hepatocytes were demonstrated. In the TUNEL assay, propolis administration reduced hepatocyte apoptosis. Propolis showed a significant hepatoprotective effect in this experimental obstructive jaundice model. 2008 S. Karger AG, Basel

  17. Raman analyses of residual stress in diamond thin films grown on Ti6Al4V alloy

    Directory of Open Access Journals (Sweden)

    Adriana F. Azevedo

    2003-01-01

    Full Text Available The stress evolution in diamond films grown on Ti6Al4V was investigated in order to develop a comprehensive view of the residual stress formation. Residual stress is composed of intrinsic stress induced during diamond film growth and extrinsic stress caused by the different thermal expansion coefficients between the film and substrate. In the coalescence stage it has been observed that the residual stress is dominated by the microstructure, whereas on continuous films, the thermal stress is more important. In this work diamond thin films with small grain size and good size and good quality were obtained in a surface wave-guide microwave discharge, the Surfatron system, with a negative bias voltage applied between the plasma shell and substrate. For above of -100V applied bias, the ratio of carbon sp³/sp² bond may increase and the nucleation rate increase arising the high value at the -250V applied bias. Stress measurements and sp³ content in the film were studied by Raman scattering spectroscopy. The total residual stress is compressive and varied from -1.52 to -1.48 GPa between 0 and -200 V applied bias, respectively, and above the -200 V, the compressive residual stress increased drastically to -1.80 GPa. The diamond nucleation density was evaluated by top view SEM images.

  18. Stress Distribution in Roots Restored with Fiber Posts and An Experimental Dentin Post: 3D-FEA.

    Science.gov (United States)

    Diana, Hugo Henrique; Oliveira, Juliana Santos; Ferro, Mariana Carolina de Lara; Silva-Sousa, Yara T Corrêa; Gomes, Érica Alves

    2016-01-01

    The aim of this study was to compare the stress distribution in radicular dentin of a maxillary canine restored with either a glass fiber post, carbon fiber post or an experimental dentin post using finite element analysis (3D-FEA). Three 3D virtual models of a maxillary canine restored with a metal-ceramic crown and glass fiber post (GFP), carbon fiber post (CFP), and experimental dentin post (DP) were obtained based on micro-CT images. A total of 180 N was applied on the lingual surface of the incisal third of each tooth at 45 degrees. The models were supported by the periodontal ligament fixed in three axes (x=y=z=0). The von Mises stress (VMS) of radicular dentin and the intracanal posts was calculated. The structures of all groups showed similar values (MPa) and distribution of maximum von Mises stress. Higher stress was found in the apical third of dentin while the posts presented homogeneous stress distribution along the axis. The fiber and dentin posts exhibited similar stress values and distribution. Thus, the experimental dentin post is a promising restorative material.

  19. Acoustic emission analyses and wavelet analyses for early detection of damage in rotating components under high stress; Schallemissions- und Waveletanalysen zur fruehzeitigen Schadenserkennung an hochbelasteten rotierenden Bauteilen

    Energy Technology Data Exchange (ETDEWEB)

    Scheer, C.; Reimche, W.; Bach, F.W. [Institut fuer Werkstoffkunde, Leibniz Universitaet Hannover (Germany)

    2007-07-01

    Machines and systems of the industrial production process must meet maximum demands in terms of operational safety, high availability, and also economic efficiency. Condition monitoring, with subsequent maintenance as required, can improve material economy and operational efficieny, provided that accurate information is obtained on the technical condition of machine components and of the overall system. Analysis of structure-borne noise and vibrations using statistical time and frequency characteristics and combined with spectral and correlational analyses are a useful tool for detecting and localising defects and abnormal operating conditions. For example, early detection of crack initiation in shafts and toothed gears is possible by means of acoustic emission signals. Acoustic emission analysis is an established technique for detecting cracks in storage tanks, pressure vessels, pipelines and static structures. I contrast to vibration analysis, it uses sensors that vibrate in their resonance frequency from about 50 kHz to up to 2 MHz. (orig.)

  20. Experimental and Computational Method for Determining Parameters of Stress-Strain State from the Data Obtainable by Interference Optical Techniques

    Directory of Open Access Journals (Sweden)

    Razumovsky I.

    2010-06-01

    Full Text Available Experimental and computational method for determining parameters of stress-strain state is proposed which is based on estimation of compliance between the data sets obtained experimentally and the results of numerical calculations of the boundary problems in formulation of which all distinctive features of area geometry, character of the loads being considered and deformation characteristics of materials are taken into account. The procedure proposed was checked at a number of practically important problems.

  1. Quantifying the Stress Responses of Brassica Rapa Genotypes, With Experimental Drought in Two Nitrogen Treatments

    Science.gov (United States)

    Hickerson, J. L.; Pleban, J. R.; Mackay, D. S.; Aston, T.; Ewers, B. E.; Weinig, C.

    2014-12-01

    In a greenhouse study designed to quantify and compare stress responses of four genotypes of Brassica rapa, broccolette (bro), cabbage (cab), turnip (tur), and oil, leaf water potential and net CO2 assimilations were measured. Individuals from each genotype, grown either with high or low nitrogen, were exposed to experimental drought of the same duration. One hypothesis was that the genotypes would differ significantly in their responses to periodic drought. The other hypothesis was that the nitrogen treatment versus no nitrogen treatment would play a significant role in the stress responses during drought. It would be expected that the nitrogen treated would have greater dry leaf mass. A LI-6400 XT portable photosynthesis system was used to obtain A/Ci curves (net CO2 assimilation rate versus substomatal CO2) for each treatment group. Predawn and midday water potentials were obtained throughout the hydrated and drought periods using a Model 670 pressure chamber. The dry leaf mass was significantly greater among the high nitrogen group versus the low nitrogen group for each genotype. Nitrogen and genotype were both determinants in variation of water potentials and net CO2 assimilation. Bro and cab genotypes with high nitrogen showed the highest net CO2 assimilation rates during hydration, but the assimilation rates dropped to the lowest during droughts. The water potentials for bro and cab were lower than values for tur and oil. Nitrogen treated genotypes had lower water potentials, but higher net CO2 assimilation rates. Bayesian ecophysiological modeling with the TREES model showed significant differences in trait expression, quantified in terms of differences in model parameter posteriors, among the four genotypes.

  2. Region-Specific Vulnerability to Oxidative Stress, Neuroinflammation, and Tau Hyperphosphorylation in Experimental Diabetes Mellitus Mice.

    Science.gov (United States)

    Elahi, Montasir; Hasan, Zafrul; Motoi, Yumiko; Matsumoto, Shin-Ei; Ishiguro, Koichi; Hattori, Nobutaka

    2016-01-01

    Recent epidemiological evidence suggests that diabetes mellitus (DM) is a risk factor for Alzheimer's disease (AD). One of the pathological hallmarks of AD is hyperphosphorylated tau protein, which forms neurofibrillary tangles. Oxidative stress and the activation of inflammatory pathways are features that are associated with both DM and AD. However, the brain region specificity of AD-related neurodegeneration, which mainly occurs in the hippocampus while the cerebellum is relatively unaffected, has not yet been clarified. Therefore, we used experimental DM mice (caused by an intraperitoneal injection of streptozotocin [STZ]) to determine whether these neurodegeneration-associated mechanisms were associated with region-specific selective vulnerability or tau phosphorylation. The hippocampus, midbrain, and cerebellum of aged (14 to 18 months old) non-transgenic (NTg) and transgenic mice overexpressing wild-type human tau (Tg601 mice) were evaluated after a treatment with STZ. The STZ injection increased reactive oxygen species, lipid peroxidation markers such as 4-hydroxynonenal and malondialdehyde in the hippocampus, but not in the midbrain or cerebellum. The STZ treatment also increased the number of Iba-1-positive and CD68-positive microglial cells, astrocytes, and IL-1β, IL-6, IL-10, and IL-18 levels in the hippocampus, but not in the midbrain or cerebellum. Tau hyperphosphorylation was also enhanced in the hippocampus, but not in the midbrain or cerebellum. When the effects of STZ were compared between Tg601 and NTg mice, microglial proliferation and elevations in IL-6 and phosphorylated tau were higher in Tg601 mice. These results suggest that neuroinflammation and oxidative stress in STZ-treated mice are associated with tau hyperphosphorylation, which may contribute to selective neurodegeneration in human AD.

  3. Astragaloside IV attenuates experimental autoimmune encephalomyelitis of mice by counteracting oxidative stress at multiple levels.

    Directory of Open Access Journals (Sweden)

    Yixin He

    Full Text Available Multiple sclerosis (MS is a chronic autoimmune neuroinflammatory disease found mostly in young adults in the western world. Oxidative stress induced neuronal apoptosis plays an important role in the pathogenesis of MS. In current study, astragaloside IV (ASI, a natural saponin molecule isolated from Astragalus membranceus, given at 20 mg/kg daily attenuated the severity of experimental autoimmune encephalomyelitis (EAE in mice significantly. Further studies disclosed that ASI treatment inhibited the increase of ROS and pro-inflammatory cytokine levels, down-regulation of SOD and GSH-Px activities, and elevation of iNOS, p53 and phosphorylated tau in central nervous system (CNS as well as the leakage of BBB of EAE mice. Meanwhile, the decreased ratio of Bcl-2/Bax was reversed by ASI. Moreover, ASI regulated T-cell differentiation and infiltration into CNS. In neuroblast SH-SY5Y cells, ASI dose-dependently reduced cellular ROS level and phosphorylation of tau in response to hydrogen peroxide challenge by modulation of Bcl-2/Bax ratio. ASI also inhibited activation of microglia both in vivo and in vitro. iNOS up-regulation induced by IFNγ stimulation was abolished by ASI dose-dependently in BV-2 cells. In summary, ASI prevented the severity of EAE progression possibly by counterbalancing oxidative stress and its effects via reduction of cellular ROS level, enhancement of antioxidant defense system, increase of anti-apoptotic and anti-inflammatory pathways, as well as modulation of T-cell differentiation and infiltration into CNS. The study suggested ASI may be effective for clinical therapy/prevention of MS.

  4. Phenotypic, physiological and malt quality analyses of US barley varieties subjected to short periods of heat and drought stress

    Science.gov (United States)

    Drought and heat are major abiotic stresses that significantly reduce crop yield and seed quality. In this study, we examined the impact of heat, drought and combined effect of heat and drought stress imposed during the grain filling stage in 18 US spring barley varieties. These impacts were assesse...

  5. Experimental hyperprolinemia induces mild oxidative stress, metabolic changes, and tissue adaptation in rat liver.

    Science.gov (United States)

    Ferreira, Andréa G K; da Cunha, Aline A; Machado, Fernanda R; Pederzolli, Carolina D; Dalazen, Giovana R; de Assis, Adriano M; Lamers, Marcelo L; dos Santos, Marinilce F; Dutra-Filho, Carlos S; Wyse, Angela T S

    2012-01-01

    The present study investigated the effects of chronic hyperprolinemia on oxidative and metabolic status in liver and serum of rats. Wistar rats received daily subcutaneous injections of proline from their 6th to 28th day of life. Twelve hours after the last injection the rats were sacrificed and liver and serum were collected. Results showed that hyperprolinemia induced a significant reduction in total antioxidant potential and thiobarbituric acid-reactive substances. The activities of the antioxidant enzymes catalase and superoxide dismutase were significantly increased after chronic proline administration, while glutathione (GSH) peroxidase activity, dichlorofluorescin oxidation, GSH, sulfhydryl, and carbonyl content remained unaltered. Histological analyses of the liver revealed that proline treatment induced changes of the hepatic microarchitecture and increased the number of inflammatory cells and the glycogen content. Biochemical determination also demonstrated an increase in glycogen concentration, as well as a higher synthesis of glycogen in liver of hyperprolinemic rats. Regarding to hepatic metabolism, it was observed an increase on glucose oxidation and a decrease on lipid synthesis from glucose. However, hepatic lipid content and serum glucose levels were not changed. Proline administration did not alter the aminotransferases activities and serum markers of hepatic injury. Our findings suggest that hyperprolinemia alters the liver homeostasis possibly by induction of a mild degree of oxidative stress and metabolic changes. The hepatic alterations caused by proline probably do not implicate in substantial hepatic tissue damage, but rather demonstrate a process of adaptation of this tissue to oxidative stress. However, the biological significance of these findings requires additional investigation. Copyright © 2011 Wiley Periodicals, Inc.

  6. Dynamic changes in eIF4F-mRNA interactions revealed by global analyses of environmental stress responses.

    Science.gov (United States)

    Costello, Joseph L; Kershaw, Christopher J; Castelli, Lydia M; Talavera, David; Rowe, William; Sims, Paul F G; Ashe, Mark P; Grant, Christopher M; Hubbard, Simon J; Pavitt, Graham D

    2017-10-27

    Translation factors eIF4E and eIF4G form eIF4F, which interacts with the messenger RNA (mRNA) 5' cap to promote ribosome recruitment and translation initiation. Variations in the association of eIF4F with individual mRNAs likely contribute to differences in translation initiation frequencies between mRNAs. As translation initiation is globally reprogrammed by environmental stresses, we were interested in determining whether eIF4F interactions with individual mRNAs are reprogrammed and how this may contribute to global environmental stress responses. Using a tagged-factor protein capture and RNA-sequencing (RNA-seq) approach, we have assessed how mRNA associations with eIF4E, eIF4G1 and eIF4G2 change globally in response to three defined stresses that each cause a rapid attenuation of protein synthesis: oxidative stress induced by hydrogen peroxide and nutrient stresses caused by amino acid or glucose withdrawal. We find that acute stress leads to dynamic and unexpected changes in eIF4F-mRNA interactions that are shared among each factor and across the stresses imposed. eIF4F-mRNA interactions stabilised by stress are predominantly associated with translational repression, while more actively initiating mRNAs become relatively depleted for eIF4F. Simultaneously, other mRNAs are insulated from these stress-induced changes in eIF4F association. Dynamic eIF4F-mRNA interaction changes are part of a coordinated early translational control response shared across environmental stresses. Our data are compatible with a model where multiple mRNA closed-loop complexes form with differing stability. Hence, unexpectedly, in the absence of other stabilising factors, rapid translation initiation on mRNAs correlates with less stable eIF4F interactions.

  7. Econometric Mediation Analyses: Identifying the Sources of Treatment Effects from Experimentally Estimated Production Technologies with Unmeasured and Mismeasured Inputs.

    Science.gov (United States)

    Heckman, James; Pinto, Rodrigo

    2015-01-01

    This paper presents an econometric mediation analysis. It considers identification of production functions and the sources of output effects (treatment effects) from experimental interventions when some inputs are mismeasured and others are entirely omitted. JEL Code: D24, C21, C43, C38.

  8. The influence of the design matrix on treatment effect estimates in the quantitative analyses of single-subject experimental design research.

    Science.gov (United States)

    Moeyaert, Mariola; Ugille, Maaike; Ferron, John M; Beretvas, S Natasha; Van den Noortgate, Wim

    2014-09-01

    The quantitative methods for analyzing single-subject experimental data have expanded during the last decade, including the use of regression models to statistically analyze the data, but still a lot of questions remain. One question is how to specify predictors in a regression model to account for the specifics of the design and estimate the effect size of interest. These quantitative effect sizes are used in retrospective analyses and allow synthesis of single-subject experimental study results which is informative for evidence-based decision making, research and theory building, and policy discussions. We discuss different design matrices that can be used for the most common single-subject experimental designs (SSEDs), namely, the multiple-baseline designs, reversal designs, and alternating treatment designs, and provide empirical illustrations. The purpose of this article is to guide single-subject experimental data analysts interested in analyzing and meta-analyzing SSED data. © The Author(s) 2014.

  9. Experimental Study on Stress Monitoring of Sand-Filled Steel Tube during Impact Using Piezoceramic Smart Aggregates.

    Science.gov (United States)

    Du, Guofeng; Zhang, Juan; Zhang, Jicheng; Song, Gangbing

    2017-08-22

    The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structure under an impact is important for structural health monitoring. In this paper, piezoceramic Smart Aggregates (SAs) are embedded into a quartz Sand-Filled Steel Tube Column (SFSTC) to monitor the internal structural stress during impacts. The piezoceramic smart aggregates are first calibrated by an impact hammer. Tests are conducted to study the feasibility of monitoring the internal stress of a structure. The results reflect that the calibration value of the piezoceramic smart aggregate sensitivity test is in good agreement with the theoretical value, and the output voltage value of the piezoceramic smart aggregate has a good linear relationship with external forces. Impact tests are conducted on the sand-filled steel tube with embedded piezoceramic smart aggregates. By analyzing the output signal of the piezoceramic smart aggregates, the internal stress state of the structure can be obtained. Experimental results demonstrated that, under the action of impact loads, the piezoceramic smart aggregates monitor the compressive stress at different locations in the steel tube, which verifies the feasibility of using piezoceramic smart aggregate to monitor the internal stress of a structure.

  10. Co-expression and promoter content analyses assign a role in biotic and abiotic stress responses to plant natriuretic peptides

    Directory of Open Access Journals (Sweden)

    Murray Shane

    2008-02-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs are a class of systemically mobile molecules distantly related to expansins. While several physiological responses to PNPs have been reported, their biological role has remained elusive. Here we use a combination of expression correlation analysis, meta-analysis of gene expression profiles in response to specific stimuli and in selected mutants, and promoter content analysis to infer the biological role of the Arabidopsis thaliana PNP, AtPNP-A. Results A gene ontology analysis of AtPNP-A and the 25 most expression correlated genes revealed a significant over representation of genes annotated as part of the systemic acquired resistance (SAR pathway. Transcription of these genes is strongly induced in response to salicylic acid (SA and its functional synthetic analogue benzothiadiazole S-methylester (BTH, a number of biotic and abiotic stresses including many SA-mediated SAR-inducing conditions, as well as in the constitutive SAR expressing mutants cpr5 and mpk4 which have elevated SA levels. Furthermore, the expression of AtPNP-A was determined to be significantly correlated with the SAR annotated transcription factor, WRKY 70, and the promoters of AtPNP-A and the correlated genes contain an enrichment in the core WRKY binding W-box cis-elements. In constitutively expressing WRKY 70 lines the expression of AtPNP-A and the correlated genes, including the SAR marker genes, PR-2 and PR-5, were determined to be strongly induced. Conclusion The co-expression analyses, both in wild type and mutants, provides compelling evidence that suggests AtPNP-A may function as a component of plant defence responses and SAR in particular. The presented evidence also suggests that the expression of AtPNP-A is controlled by WRKY transcription factors and WRKY 70 in particular. AtPNP-A shares many characteristics with PR proteins in that its transcription is strongly induced in response to pathogen challenges, it

  11. Experimental and finite element analysis of residual stress and distortion in GTA welding of modified 9Cr-1Mo steel

    Energy Technology Data Exchange (ETDEWEB)

    Zubairuddin, M.; Chaudhari, V. [Institute for Plasma Research, Gandhinagar (India); Albert, S. K.; Mahadevan, S.; Vasudevan, M. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Suri, V. K. [Bhabha Atomic Research Centre, Mumbai (India)

    2014-12-15

    In this paper, investigation of residual stress and distortion induced in 3 mm thick Modified 9Cr-1Mo steel plates during GTA welding is carried out. SYSWELD software is used for the thermo-mechanical analysis. A 3D meshed model is created for the simulation and double ellipsoidal heat source distribution is used for the thermal analysis. Thermal cycles predicted near the fusion zone are compared with experimentally measured thermal cycles using thermocouples. Predicted residual stress profile across the fusion zone is compared with the measured profile using X-ray diffraction method. There is a good agreement between measured and predicted thermal cycles and residual stress profile. Distortion of the weld joint is measured using vertical electronic height gauge. Finite element analysis of distortion of the weld joint is carried out by applying both large and small distortion theories. Comparison of experimental and numerical results showed better accuracy if large distortion theory is applied.

  12. Experimental studies of the stress state of the surface layer of detailat treatment with submerged jets

    Directory of Open Access Journals (Sweden)

    Олександр Олександрович Анділахай

    2015-03-01

    Full Text Available In the instrument and electrical industry was the use of the method of abrasive machining submerged jet, which is the most promising method for abrasive blasting of small parts of low stiffness. This method eliminates the main drawback сhip plants - abrasion channel nozzles or injection nozzles, but the state of the surface layer of machined parts are poorly understood and to make maximum use of the potential to provide the required quality parameters. The study of the state of the surfaces of parts resulting from abrasive blasting traditional methods, dedicated work, which define quality indicators: microhardness depth residual stress, as well as their nature (compressive, tensile. However, known from the literature values correspond to the conditions of surface treatment of parts in a fixed state with an abrasive material through the feed nozzle, and therefore the dynamics of the interaction of a single abrasive grain and significantly different parts. The process in question, and different modes of processing characteristics of the abrasive grains. In the paper, a series of experimental studies designed to assess the state of machined surfaces of parts as a result of abrasion submerged jets. It is established that during the treatment the non-oriented disorderly traces overlay the abrasive grains on the treated surface, thereby forming a tight skin layer thickness of 4 - 5 micrometers. Processed surface gets cold working, as evidenced by the study of microhardness before and after abrasive machining in a free state submerged jets

  13. Alpha-Amanitin Poisoning, Nephrotoxicity and Oxidative Stress: An Experimental Mouse Model

    Science.gov (United States)

    Ergin, Mehmet; Dundar, Zerrin Defne; Kilinc, Ibrahim; Colak, Tamer; Oltulu, Pembe; Girisgin, Abdullah Sadik

    2015-01-01

    Background: Alpha-amanitin (α-AMA) plays a major role in Amanita phalloides poisoning, showing toxic effects on multi-organs, particularly on the liver and kidneys. Studies have shown a relationship between α-AMA-related injuries and reactive oxygen species. Objectives: We aimed to investigate whether there is renal injury and its relationship with oxidative stress after intraperitoneal injection of α-AMA in mice experimental poisoning models. Materials and Methods: There were 37 male BALB/c laboratory mice treated with α-AMA, according to the study groups: control group (n = 7); low dose (0.2 mg/kg) (n = 10); moderate dose (0.6 mg/kg) (n = 10), and high dose (1 mg/kg) (n = 10). The sample size was detected according to the ethical committee’s decision as well as similar studies in the literature. After a 48-hour follow-up period, all the subjects were sacrificed for pathological and biochemical assays. The study was held in Turkey. Results: α-AMA poisoning in mice results in inflammatory changes and necrosis in renal structures. There were statistically significant differences between the study groups regarding measured levels of catalase, superoxide dismutase, glutathione peroxidase, total antioxidant status (TAS), total oxidant status (TOS) and malonyl dialdehyde in renal homogenates of mice (P poisoning in mice led to inflammatory changes and necrosis in renal structures. Biochemical analysis showed a shift in the oxidative/anti-oxidative balance towards the oxidative status. PMID:26430527

  14. Stress During Development of Experimental Endometriosis Influences Nerve Growth and Disease Progression.

    Science.gov (United States)

    Cuevas, Marielly; Cruz, Myrella L; Ramirez, Antonio E; Flores, Idhaliz; Thompson, Kenira J; Bayona, Manuel; Vernon, Michael W; Appleyard, Caroline B

    2017-01-01

    We have previously shown that stress prior to induction worsens clinical presentation and inflammatory parameters in a rat model of endometriosis. This study was designed to examine whether stress during the development of endometriosis can affect the growth of endometriotic implants through nerve growth and immune alterations. Endometriosis was surgically induced in female Sprague-Dawley rats by suturing uterine horn implants onto the small intestine mesentery. Two weeks later, one group of rats (endo-stress) was subjected to a 10-day swim stress protocol. Controls had no stress (endo-no stress) or sutures only and stress (sham-stress). On day 60, all rats were killed and examined for the presence of endometriotic vesicles. The size of each vesicle was measured. The uterus and colon were removed and assessed for damage, cell infiltration, and expression of nerve growth factor (NGF), its receptors (p75 and Tropomyosin receptor kinase A (Trk-A)/pTrk-A), and calcitonin gene-related peptide, a sensory fiber marker. A differential analysis of peritoneal fluid white blood cell count was performed. Stress significantly increased endometriotic vesicle size but not colonic damage and increased infiltration of mast cells. Significantly increased expression of NGF and its receptors was found in the uterus of animals with endometriosis receiving stress. Stress stimulates the development of ectopic endometrial vesicles in an animal model of endometriosis and increases inflammatory cell recruitment to the peritoneum. In addition, stress promotes nerve fiber growth in the uterus.

  15. Experimental Study on the Anisotropic Stress-Strain Behavior of Polycrystalline Ni-Mn-Ga in Directional Solidification

    Science.gov (United States)

    Teng, Yao; Shi, Tao; Zhu, Yuping; Li, Zongbin; Deng, Tao; Bai, Guonan

    2016-03-01

    A polycrystalline Ni-Mn-Ga ferromagnetic shape memory alloy produced by directional solidification is the subject of this research paper. The compressive stress-strain curves of the material for different cutting angles to the solidification direction are tested. The martensite Young's modulus, macroscopic reorientation strain, and phase transition critical stress are analyzed experimentally. The results show that mechanical behaviors in the loading-unloading cycle of the material present nonlinear and anisotropic characteristics, which are all closely related to the material's orientation to the solidification direction. The martensite Young's modulus, macroscopic reorientation strain, and phase transition critical stress achieve maximum values in the solidification direction. A 50° orientation to the solidification direction is the cut-off direction of the mechanical properties, where the martensite Young's modulus and reorientation start critical stress reach minimum values. The present study is expected to provide sound guidance for practical applications.

  16. Experimental and Numerical Research of Stress-Strain State of Homogeneous Soil Massif at Interaction with Single Barrette

    Science.gov (United States)

    Ter-Martirosyan, Z. G.; Ter-Martirosyan, A. Z.; Sidorov, V. V.

    2017-11-01

    Deep foundations are used for the design of high-rise buildings due to a large pressure transfer on the soil base. The foundations of buildings sometimes use barrettes which are able to perceive significant vertical and horizontal loads due to improved lateral surface. Barrettes have increased load bearing capacity as compared with large diameter piles. In modern practice the interaction between barrettes and soil is investigated by analytical and numerical methods and has no sufficient experimental confirmation. The review of experimental methods for the research of the intense stress-strain state of the uniform soil massif at interaction with elements of a deep foundation is provided in this article. Experimental research are planned with the use of laboratory stand for the purpose of qualitative data obtaining on the interaction barrettes with an assessment of a settlement model adequacy and also at the research of the intense stress-strain state by numerical methods.

  17. Theoretical and experimental evaluation of effective stress-induced sorption capacity change and its influence on coal permeability

    Science.gov (United States)

    Li, Chengwu; Dong, Lihui; Xu, Xiaomeng; Hu, Po; Tian, Jianwei; Zhang, Yihuai; Yang, Leilei

    2017-06-01

    The gas sorption effect is an important factor affecting the gas permeability of a coal seam, which has been proved in many previous experimental measurements and analytical permeability studies. However, the sorption capacity of coal is usually not static due to the complexity of external stress variation and internal gas media features. The stress-induced sorption capacity variation and its effect on the coal permeability change have not been fully identified yet. Thus, in this paper we present a preliminary evaluation of the stress-induced sorption capacity change by introducing the adsorption capacity modified term, and an experiment is carried out to verify the influence of the altered effective stress on coal permeability. Langmuir-like adsorption deformation constant parameters were combined into the modified coal permeability model and were given values to fully estimate the influence on permeability caused by the modification term. We found that different change modes of effective stress would yield different change effects on the permeability, that is, with the same effective stress change amount, the altered external stress-induced change had less influence than the altered-pore pressure-induced change; however, both modes demonstrated that the model taking sorption capacity change into consideration is more consistent with the experimental data. The effect of sorption capacity change on coal permeability variation was also found to be tightly connected with the physical and mechanical properties of the coal itself. It is proved that considering stress-induced sorption ability change has a critical role in characterizing the permeability variation of coal.

  18. Experimental and numerical analyses of pure copper during ECFE process as a novel severe plastic deformation method

    Directory of Open Access Journals (Sweden)

    M. Ebrahimi

    2014-02-01

    Full Text Available In this paper, a new severe plastic deformation method called equal channel forward extrusion (ECFE process has been proposed and investigated by experimental and numerical approaches on the commercial pure copper billets. The experimental results indicated that the magnitudes of yield strength, ultimate tensile strength and Vickers micro-hardness have been markedly improved from 114 MPa, 204 MPa and 68 HV as the annealed condition to 269 MPa, 285 MPa and 126 HV after the fourth pass of ECFE process, respectively. In addition, scanning electron microscopy observation of the samples showed that the average grain size of the as-received state which is about 22 μm has been reduced to 1.4 μm after the final pass. The numerical investigation suggested that although one pass ECFE process fabricates material with the mean effective strain magnitude of about 1, the level of imposed effective plastic strain gradually diminishes from the circumference to the center of the deformed billet.

  19. The effectiveness of telehealth care on caregiver burden, mastery of stress, and family function among family caregivers of heart failure patients: a quasi-experimental study.

    Science.gov (United States)

    Chiang, Li-Chi; Chen, Wan-Chou; Dai, Yu-Tzu; Ho, Yi-Lwun

    2012-10-01

    Telehealth care was developed to provide home-based monitoring and support for patients with chronic disease. The positive effects on physical outcome have been reported; however, more evidence is required concerning the effects on family caregivers and family function for heart failure patients transitioning from the hospital to home. To evaluate the effectiveness of nursing-led transitional care combining discharge plans and telehealth care on family caregiver burden, stress mastery and family function in family caregivers of heart failure patients compared to those receiving traditional discharge planning only. This is a quasi-experimental study design. Sixty-three patients with heart failure were assessed for eligibility and invited to participate in either telehealth care or standard care in a medical centre from May to October 2010. Three families refused to participate in data collection. Thirty families who chose telehealth care after discharge from the hospital to home comprised the experimental group; the others families receiving discharge planning only comprised the comparison group. Telenursing specialist provided the necessary family nursing interventions by 24-h remote monitoring of patients' health condition and counselling by telephone, helping the family caregivers successfully transition from hospital to home. Data on caregiver burden, stress mastery and family function were collected before discharge from the hospital and one month later at home. Effects of group, time, and group×time interaction were analysed using Mixed Model in SPSS (17.0). Family caregivers in both groups had significantly lower burden, higher stress mastery, and better family function at one-month follow-up compared to before discharge. The total score of caregiver burden, stress mastery and family function was significantly improved for the family caregivers in the experimental group compared to the comparison group at posttest. Two subscales of family function

  20. The SULTR gene family in maize (Zea mays L.): Gene cloning and expression analyses under sulfate starvation and abiotic stress.

    Science.gov (United States)

    Huang, Qin; Wang, Meiping; Xia, Zongliang

    2017-11-10

    Sulfur is an essential macronutrient required for plant growth, development and stress responses. The family of sulfate transporters (SULTRs) mediates the uptake and translocation of sulfate in higher plants. However, basic knowledge of the SULTR gene family in maize (Zea mays L.) is scarce. In this study, a genome-wide bioinformatic analysis of SULTR genes in maize was conducted, and the developmental expression patterns of the genes and their responses to sulfate starvation and abiotic stress were further investigated. The ZmSULTR family includes eight putative members in the maize genome and is clustered into four groups in the phylogenetic tree. These genes displayed differential expression patterns in various organs of maize. For example, expression of ZmSULTR1;1 and ZmSULTR4;1 was high in roots, and transcript levels of ZmSULTR3;1 and ZmSULTR3;3 were high in shoots. Expression of ZmSULTR1;2, ZmSULTR2;1, ZmSULTR3;3, and ZmSULTR4;1 was high in flowers. Also, these eight genes showed differential responses to sulfate deprivation in roots and shoots of maize seedlings. Transcript levels of ZmSULTR1;1, ZmSULTR1;2, and ZmSULTR3;4 were significantly increased in roots during 12-day-sulfate starvation stress, while ZmSULTR3;3 and ZmSULTR3;5 only showed an early response pattern in shoots. In addition, dynamic transcriptional changes determined via qPCR revealed differential expression profiles of these eight ZmSULTR genes in response to environmental stresses such as salt, drought, and heat stresses. Notably, all the genes, except for ZmSULTR3;3, were induced by drought and heat stresses. However, a few genes were induced by salt stress. Physiological determination showed that two important thiol-containing compounds, cysteine and glutathione, increased significantly under these abiotic stresses. The results suggest that members of the SULTR family might function in adaptations to sulfur deficiency stress and adverse growing environments. This study will lay a

  1. Homocysteine measurement in pig saliva, assay validation and changes after acute stress and experimental inflammation models: A pilot study.

    Science.gov (United States)

    Tecles, F; Escribano, D; Martínez-Miró, S; Cerón, J J

    2017-06-01

    High homocysteine (Hcy) concentration in serum has been associated to stress and inflammation in humans, but this association has not been studied in saliva in any animal species. The purpose of this research was to study salivary Hcy levels in pigs under stressful and inflammatory conditions. A commercially available enzyme-linked immunosorbent assay specific for Hcy determination in pigs was adapted and validated in saliva, yielding reproducible and accurate results. Hcy was measured in paired serum-saliva samples and no correlation was observed between serum and salivary Hcy. Salivary Hcy was measured in two experimental models of stress induction in pigs: restraint with a nasal snare and isolation. Homocysteine concentration and the homocysteine to total protein (Hcy/TP) ratio significantly increased 15min after restraining and decreased after some days of isolation. Significant correlation was observed between Hcy and chromogranin A. After an experimentally induced inflammation by subcutaneous turpentine injection, salivary Hcy increased only 3h after turpentine administration; however, the Hcy/TP ratio did not show any change. No correlation was found between salivary Hcy and serum C-reactive protein. In conclusion, salivary Hcy concentration increased when pigs were restrained with a nasal snare or stressed by isolation, probably reflecting an increase in the sympathetic activity. On the other hand, Hcy increased after an experimental inflammation induced by turpentine administration but in this case probably reflects an increase in total protein production in saliva. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Oxidative Stress in Wild Boars Naturally and Experimentally Infected with Mycobacterium bovis.

    Directory of Open Access Journals (Sweden)

    Diana Gassó

    Full Text Available Reactive oxygen and nitrogen species (ROS-RNS are important defence substances involved in the immune response against pathogens. An excessive increase in ROS-RNS, however, can damage the organism causing oxidative stress (OS. The organism is able to neutralise OS by the production of antioxidant enzymes (AE; hence, tissue damage is the result of an imbalance between oxidant and antioxidant status. Though some work has been carried out in humans, there is a lack of information about the oxidant/antioxidant status in the presence of tuberculosis (TB in wild reservoirs. In the Mediterranean Basin, wild boar (Sus scrofa is the main reservoir of TB. Wild boar showing severe TB have an increased risk to Mycobacterium spp. shedding, leading to pathogen spreading and persistence. If OS is greater in these individuals, oxidant/antioxidant balance in TB-affected boars could be used as a biomarker of disease severity. The present work had a two-fold objective: i to study the effects of bovine TB on different OS biomarkers (namely superoxide dismutase (SOD, catalasa (CAT, glutathione peroxidase (GPX, glutathione reductase (GR and thiobarbituric acid reactive substances (TBARS in wild boar experimentally challenged with Mycobacterium bovis, and ii to explore the role of body weight, sex, population and season in explaining the observed variability of OS indicators in two populations of free-ranging wild boar where TB is common. For the first objective, a partial least squares regression (PLSR approach was used whereas, recursive partitioning with regression tree models (RTM were applied for the second. A negative relationship between antioxidant enzymes and bovine TB (the more severe lesions, the lower the concentration of antioxidant biomarkers was observed in experimentally infected animals. The final PLSR model retained the GPX, SOD and GR biomarkers and showed that 17.6% of the observed variability of antioxidant capacity was significantly correlated

  3. Experimentally studied laser fluorescence method for remote sensing of plant stress situation induced by improper plants watering

    Directory of Open Access Journals (Sweden)

    Yu. V. Fedotov

    2014-01-01

    Full Text Available Stressful situations of plants can be caused by a lack of nutrients; mechanical damages; diseases; low or high temperatures; lack of illumination; insufficient or excess humidity of the soil; soil salinization; soil pollution by oil products or heavy metals; the increased acidity of the soil; use of pesticides, herbicides, insecticides, etc.At early stages it is often difficult to detect seemingly that the plants are in stressful situations caused by adverse external factors. However, the fluorescent analysis potentially allows detection of the stressful situations of plants by deformation of laser-induced fluorescence spectra. The paper conducts experimental investigations to learn the capabilities of the laser fluorescent method to monitor plant situations at 532nm wavelength of fluorescence excitation in the stressful situations induced by improper watering (at excess of moisture in the soil and at a lack of moisture.Researches of fluorescence spectra have been conducted using a created laboratory installation. As a source to excite fluorescence radiation the second harmonica of YAG:Nd laser is used. The subsystem to record fluorescence radiation is designed using a polychromator and a highly sensitive matrix detector with the amplifier of brightness.Experimental investigations have been conducted for fast-growing and unpretentious species of plants, namely different sorts of salad.Experimental studies of laser-induced fluorescence spectra of plants for 532nm excitement wavelength show that the impact of stressful factors on a plant due to the improper watering, significantly distorts a fluorescence spectrum of plants. Influence of a stressful factor can be shown as a changing profile of a fluorescence spectrum (an identifying factor, here, is a relationship of fluorescence intensities at two wavelengths, namely 685 nm and 740 nm or (and as a changing level of fluorescence that can be the basis for the laser method for monitoring the plant

  4. Impact of stress on paranoia: an experimental investigation of moderators and mediators.

    Science.gov (United States)

    Lincoln, T M; Peter, N; Schäfer, M; Moritz, S

    2009-07-01

    Vulnerability-stress models ascribe stress a pivotal role in the development of psychosis. However, moderating and mediating mechanisms translating stress into psychosis and the specificity of the association are not clearly established. It is hypothesized that stress will trigger paranoid ideation in vulnerable individuals through an increase in negative emotion. Using a repeated-measures design, 64 healthy participants with varying levels of vulnerability [psychosis symptoms assessed by the Community Assessment of Psychic Experiences (CAPE)] were assigned to a stress and a non-stress condition in random order. Stress was induced by exposing participants to building-site noise (75 dB) applied concurrently with difficult knowledge questions. Symptoms of paranoia, depression and obsessive compulsive disorder (OCD) were assessed by state-adapted versions of clinical scales. In the stress condition there was an increase in paranoia, depression and negative emotion. Multilevel linear modeling (MLM) revealed the increase in paranoia under stress to be moderated by the level of vulnerability and mediated by anxiety. Although participants generally showed an increase in anxiety under stress, anxiety was more strongly related to paranoia in participants with higher baseline symptomatology. The results support and specify the role of emotional reactions to stressors on the pathway from vulnerability to psychosis and highlight the relevance of anxiety.

  5. Effect of Camel Milk on Oxidative Stresses in Experimentally Induced Diabetic Rabbits

    Directory of Open Access Journals (Sweden)

    Esraa Tantawy

    2010-06-01

    Full Text Available Camel milk has an importance in the treatment of diabetes. It has been shown that the patients who drink camel milk daily, their need to insulin decrease. Therefore, this study aimed to investigate the effect of camel milk in comparison with insulin treatment in experimentally-induced diabetes. This study was carried out on forty male New Zealand rabbits, divided into four groups with ten rabbits in each. The first group G1 was considered as control non-diabetic group and received only normal saline solution. The other animals were injected intravenously with alloxan for induction of diabetes mellitus and then divided into three groups' ten rabbits each as the follows: G2 considered as control diabetic and left untreated, G3 was considered as diabetic and treated with insulin, and G4 was considered as diabetic and received camel milk. At the end of the experiment (4 weeks, blood (whole blood & serum and tissue samples (liver, kidney and pancreas were collected from all the animals for analysis of: enzymatic SOD and catalase, non-enzymatic GSH antioxidant enzyme activities. Serum malondialdeyde, glucose, insulin and lipid profile also were analyzed. The results showed that the camel milk was effective in the treatment of diabetes in comparison to insulin treatment alone. In addition to its hypoglycemic effect, camel milk improved the diabetes-induced oxidative stress. The histopathological evaluations demonstrated that there was a regeneration in β cells and the islets of Langerhans among the pancreatic acini in rabbits receiving camel milk. Our findings suggested that the camel milk administration in case of insulin dependant diabetes mellitus might be recommended as an oral anti-diabetic remedy.

  6. Determination of micronutrients and oxidative stress status in the blood of STZ-induced experimental diabetic rat models.

    Science.gov (United States)

    Ragbetli, Cennet; Dede, Semiha; Tanritanir, Pinar; Yoruk, Ibrahim Hakki; Ragbetli, Murat Cetin

    2014-11-01

    This study aims to research the effect of streptozotocin (STZ) at different doses on the serum micronutrients and oxidative stress status in diabetic rat models. Twenty male rats averaged 250 g and 3-4 months old were used as experimental models. They were put in four groups composed of five rats each. Diabetic was induced by administering STZ 55 and 65 mg/kg intraperitonally. The serum micronutrients including minerals and vitamins (Cu, Zn, Mg, Fe, vitamins D, E, and C) and oxidative stress (malondialdehyde, MDA) were determined. Cu, Zn, and Vitamin D3 levels were found to increase significantly in STZ groups (p micronutrients were affected significantly.

  7. Transcriptomic analyses on muscle tissues of Litopenaeus vannamei provide the first profile insight into the response to low temperature stress.

    Directory of Open Access Journals (Sweden)

    Wen Huang

    Full Text Available The Pacific white shrimp (Litopenaeus vannamei is an important cultured crustacean species worldwide. However, little is known about the molecular mechanism of this species involved in the response to cold stress. In this study, four separate RNA-Seq libraries of L. vannamei were generated from 13°C stress and control temperature. Total 29,662 of Unigenes and overall of 19,619 annotated genes were obtained. Three comparisons were carried out among the four libraries, in which 72 of the top 20% of differentially-expressed genes were obtained, 15 GO and 5 KEGG temperature-sensitive pathways were fished out. Catalytic activity (GO: 0003824 and Metabolic pathways (ko01100 were the most annotated GO and KEGG pathways in response to cold stress, respectively. In addition, Calcium, MAPK cascade, Transcription factor and Serine/threonine-protein kinase signal pathway were picked out and clustered. Serine/threonine-protein kinase signal pathway might play more important roles in cold adaptation, while other three signal pathway were not widely transcribed. Our results had summarized the differentially-expressed genes and suggested the major important signaling pathways and related genes. These findings provide the first profile insight into the molecular basis of L. vannamei response to cold stress.

  8. Physiological and proteomic analyses of the drought stress response in Amygdalus Mira (Koehne) Yü et Lu roots.

    Science.gov (United States)

    Cao, Yuan; Luo, Qiuxiang; Tian, Yan; Meng, Fanjuan

    2017-02-27

    Plants are oftentimes exposed to many types of abiotic stresses. Drought is one of the main environmental stresses which limits plant growth, distribution and crop yield worldwide. Amygdalus mira (Koehne) Yü et Lu is an important wild peach, and it is considered an ideal wild peach germplasm for improving cultivated peach plants. Because of the loss of genetic variation, cultivated peach plants are sensitive to biotic and abiotic stresses. Wild peach germplasm can offer many useful genes for peach improvement. Responses to drought by withholding water have been studied in Amygdalus mira (Koehne) Yü et Lu roots. In this study, plants were divided into well-watered (control) and water-stressed (treatment) groups, and the treatment group did not receive water until the recovery period (day 16). Several physiological parameters, including root water content and root length, were reduced by drought stress and recovered after rewatering. In addition, the relative conductivity, the levels of proline, MDA and H2O2, and the activities of ROS scavenging enzymes (POD, APX and CAT) were increased, and none of these factors, except the level of proline, recovered after rewatering. In total, 95 differentially expressed proteins were revealed after drought. The identified proteins refer to a extensive range of biological processes, molecular functions and cellular components, including cytoskeleton dynamics (3.16% of the total 95 proteins), carbohydrate and nitrogen metabolism (6.33% of the total 95 proteins), energy metabolism (7.37% of the total 95 proteins), transcription and translation (18.95% of the total 95 proteins), transport (4.21% of the total 95 proteins), inducers (3.16% of the total 95 proteins), stress and defense (26.31% of the total 95 proteins), molecular chaperones (9.47% of the total 95 proteins), protein degradation (3.16% of the total 95 proteins), signal transduction (7.37% of the total 95 proteins), other materials metabolism (5.26% of the total 95

  9. Stress

    Science.gov (United States)

    ... natural disaster. This type of stress can cause post-traumatic stress disorder (PTSD). Different people may feel stress in different ways. Some people experience digestive symptoms. Others may have headaches, sleeplessness, depressed mood, anger, ...

  10. Experimental study on relationship between processing parameters and stress wave propagation during automated fiber placement process

    Science.gov (United States)

    Fu, H. Y.; Li, W. Q.; Sun, S. Z.; Han, Z. Y.

    2017-06-01

    Automated fiber placement (AFP) is an important manufacturing method of composites, which has been widely used in the field of aerospace. Unreasonable processing parameters could lead to some manufacturing defects including pores, bubbles and cracks. In this paper, the propagation characteristics of stress waves are believed to be closely related to the defects during AFP process. Experiments are conducted to collect stress wave signal under different processing parameters (pressure, velocity and temperature) during manufacturing process. And the relationship between the processing parameters and the characteristics of stress waves is explored by Control Variate Method (CVM). Finally, the effects of laying parameters on stress amplitude, response speed and duration are summarized.

  11. An experimental and bioinformatics protocol for RNA-Seq analyses of photoperiodic diapause in the Asian tiger mosquito, Aedes albopictus.

    Science.gov (United States)

    Poelchau, Monica F; Huang, Xin; Goff, Allison; Reynolds, Julie; Armbruster, Peter

    2014-11-30

    Photoperiodic diapause is an important adaptation that allows individuals to escape harsh seasonal environments via a series of physiological changes, most notably developmental arrest and reduced metabolism. Global gene expression profiling via RNA-Seq can provide important insights into the transcriptional mechanisms of photoperiodic diapause. The Asian tiger mosquito, Aedes albopictus, is an outstanding organism for studying the transcriptional bases of diapause due to its ease of rearing, easily induced diapause, and the genomic resources available. This manuscript presents a general experimental workflow for identifying diapause-induced transcriptional differences in A. albopictus. Rearing techniques, conditions necessary to induce diapause and non-diapause development, methods to estimate percent diapause in a population, and RNA extraction and integrity assessment for mosquitoes are documented. A workflow to process RNA-Seq data from Illumina sequencers culminates in a list of differentially expressed genes. The representative results demonstrate that this protocol can be used to effectively identify genes differentially regulated at the transcriptional level in A. albopictus due to photoperiodic differences. With modest adjustments, this workflow can be readily adapted to study the transcriptional bases of diapause or other important life history traits in other mosquitoes.

  12. Thermo-Mechanical Characterization of Friction Stir Spot Welded AA7050 Sheets by Means of Experimental and FEM Analyses.

    Science.gov (United States)

    D'Urso, Gianluca; Giardini, Claudio

    2016-08-11

    The present study was carried out to evaluate how the friction stir spot welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. The experimental study was performed by means of a CNC machine tool obtaining FSSW lap joints on AA7050 aluminum alloy plates. Three thermocouples were inserted into the samples to measure the temperatures at different distance from the joint axis during the whole FSSW process. Experiments was repeated varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the tests using a piezoelectric load cell, while the mechanical properties of the joints were evaluated by executing shear tests on the specimens. The correlation found between process parameters and joints properties, allowed to identify the best technological window. The data collected during the experiments were used to validate a simulation model of the FSSW process, too. The model was set up using a 2D approach for the simulation of a 3D problem, in order to guarantee a very simple and practical solution for achieving results in a very short time. A specific external routine for the calculation of the thermal energy due to friction acting between pin and sheet was developed. An index for the prediction of the joint mechanical properties using the FEM simulations was finally presented and validated.

  13. Thermo-Mechanical Characterization of Friction Stir Spot Welded AA7050 Sheets by Means of Experimental and FEM Analyses

    Directory of Open Access Journals (Sweden)

    Gianluca D’Urso

    2016-08-01

    Full Text Available The present study was carried out to evaluate how the friction stir spot welding (FSSW process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. The experimental study was performed by means of a CNC machine tool obtaining FSSW lap joints on AA7050 aluminum alloy plates. Three thermocouples were inserted into the samples to measure the temperatures at different distance from the joint axis during the whole FSSW process. Experiments was repeated varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the tests using a piezoelectric load cell, while the mechanical properties of the joints were evaluated by executing shear tests on the specimens. The correlation found between process parameters and joints properties, allowed to identify the best technological window. The data collected during the experiments were used to validate a simulation model of the FSSW process, too. The model was set up using a 2D approach for the simulation of a 3D problem, in order to guarantee a very simple and practical solution for achieving results in a very short time. A specific external routine for the calculation of the thermal energy due to friction acting between pin and sheet was developed. An index for the prediction of the joint mechanical properties using the FEM simulations was finally presented and validated.

  14. Delineating sampling procedures: Pedagogical significance of analysing sampling descriptions and their justifications in TESL experimental research reports

    Directory of Open Access Journals (Sweden)

    Jason Miin-Hwa Lim

    2011-04-01

    Full Text Available Teaching second language learners how to write research reports constitutes a crucial component in programmes on English for Specific Purposes (ESP in institutions of higher learning. One of the rhetorical segments in research reports that merit attention has to do with the descriptions and justifications of sampling procedures. This genre-based study looks into sampling delineations in the Method-related sections of research articles on the teaching of English as a second language (TESL written by expert writers and published in eight reputed international refereed journals. Using Swales’s (1990 & 2004 framework, I conducted a quantitative analysis of the rhetorical steps and a qualitative investigation into the language resources employed in delineating sampling procedures. This investigation has considerable relevance to ESP students and instructors as it has yielded pertinent findings on how samples can be appropriately described to meet the expectations of dissertation examiners, reviewers, and supervisors. The findings of this study have furnished insights into how supervisors and instructors can possibly teach novice writers ways of using specific linguistic mechanisms to lucidly describe and convincingly justify the sampling procedures in the Method sections of experimental research reports.

  15. Experimental reduction of pain catastrophizing modulates pain report but not spinal nociception as verified by mediation analyses.

    Science.gov (United States)

    Terry, Ellen L; Thompson, Kathryn A; Rhudy, Jamie L

    2015-08-01

    Pain catastrophizing is associated with enhanced pain; however, the mechanisms by which it modulates pain are poorly understood. Evidence suggests that catastrophizing modulates supraspinal processing of pain but does not modulate spinal nociception (as assessed by nociceptive flexion reflex [NFR]). Unfortunately, most NFR studies have been correlational. To address this, this study experimentally reduced catastrophizing to determine whether it modulates spinal nociception (NFR). Healthy pain-free participants (N = 113) were randomly assigned to a brief 30-minute catastrophizing reduction manipulation or a control group that received pain education. Before and after manipulations, 2 types of painful stimuli were delivered to elicit (1) NFR (single trains of stimuli) and (2) temporal summation of NFR (3 stimulations at 2 Hz). After each set of stimuli, participants were asked to report their pain intensity and unpleasantness, as well as their situation-specific catastrophizing. Manipulation checks verified that catastrophizing was effectively reduced. Furthermore, pain intensity and unpleasantness to both stimulation types were reduced by the catastrophizing manipulation, effects that were mediated by catastrophizing. Although NFRs were not affected by the catastrophizing manipulation, temporal summation of NFR was reduced. However, this effect was not mediated by catastrophizing. These results indicate that reductions in catastrophizing lead to reductions in pain perception but do not modulate spinal nociception and provides further evidence that catastrophizing modulates pain at the supraspinal, not the spinal, level.

  16. Thermal and optical design analyses, optimizations, and experimental verification for a novel glare-free LED lamp for household applications.

    Science.gov (United States)

    Khan, M Nisa

    2015-07-20

    Light-emitting diode (LED) technologies are undergoing very fast developments to enable household lamp products with improved energy efficiency and lighting properties at lower cost. Although many LED replacement lamps are claimed to provide similar or better lighting quality at lower electrical wattage compared with general-purpose incumbent lamps, certain lighting characteristics important to human vision are neglected in this comparison, which include glare-free illumination and omnidirectional or sufficiently broad light distribution with adequate homogeneity. In this paper, we comprehensively investigate the thermal and lighting performance and trade-offs for several commercial LED replacement lamps for the most popular Edison incandescent bulb. We present simulations and analyses for thermal and optical performance trade-offs for various LED lamps at the chip and module granularity levels. In addition, we present a novel, glare-free, and production-friendly LED lamp design optimized to produce very desirable light distribution properties as demonstrated by our simulation results, some of which are verified by experiments.

  17. Thermodynamic analysis and experimental validation of SOFC system concepts; Thermodynamische Analyse von SOFC-Systemkonzepten und experimentelle Validierung

    Energy Technology Data Exchange (ETDEWEB)

    Heddrich, Marc Philipp

    2012-07-01

    The impending shortage of resources has made it necessary to investigate efficient energy conversion technologies for electric power generation, especially those that are compatible with renewable energy sources. The fuel cell technology, especially solid oxide fuel cells (SOFC) is an interesting option. The author attempts to provide a better understanding of the SOFC technology, its system concepts and potential. Real measured data of existing systems are used for model validation and for an analysis of real system performance. (orig./AKB) [German] Die Entwicklung effizienterer Energiewandlungstechnologien, zur Bereitstellung von elektrischem Strom, wird aufgrund weltweit knapper werdender Energiereserven zur Notwendigkeit. Vorzugsweise sind Technologien von Interesse, die fuer eine Kopplung mit erneuerbaren Energien gut geeignet sind. Die Brennstoffzellentechnologie und insbesondere Festoxid-Brennstoffzellen (engl.: solid oxide fuel cell, SOFC) bieten die Chance dazu. Die vorliegende Arbeit soll hier einen Beitrag leisten. Das grundsaetzliche verfahrenstechnische Verstaendnis des Einsatzes der SOFC-Technologie in Systemen soll gestaerkt werden. Die moeglichen SOFC-Systemkonzepte sollen, den Einsatz derzeit verfuegbarer Brennstoffe beruecksichtigend, erklaert und bewertet werden, um Systementwicklern und -operatoren die Potentiale und Moeglichkeiten der SOFC-Technologie aufzuzeigen. Dazu wird ein thermodynamisches Systemmodell aufgestellt. Ein Abgleich mit Messdaten betriebener Systeme dient der Modellvalidierung und der Analyse realen Systemverhaltens.

  18. A combined study based on experimental analyses and theoretical calculations on properties of poly (lactic acid) under annealing treatment

    Science.gov (United States)

    Loued, W.; Wéry, J.; Dorlando, A.; Alimi, K.

    2015-02-01

    In this paper, the significance of annealing, in two different atmospheres (air and vacuum), on the surface characteristics of poly (lactic acid) (PLA) films was investigated. X-ray diffraction (XRD) measurements correlated to atomic force microscopy (AFM) observations of the cast PLA films show that thermal treatment under air atmosphere is responsible for a significant increase of crystallinity with the increase of temperature. However, band gap energy of the title compound is slightly affected by annealing at different temperatures. As for the untreated PLA, the molecular geometry was optimized using density functional theory (DFT/B3LYP) method with 6-31g (d) basis set in ground state. From the optimized geometry, HOMO and LUMO energies and quantum chemical parameters were performed at B3LYP/6-31g (d). The theoretical results, applied to simulated optical spectra of the compound, were compared to the observed ones. On the basis of theoretical vibrational analyses, the thermodynamic properties were calculated at different temperatures, revealing the correlation between internal energy (U), enthalpy (H), entropy (S), Free energy (G) and temperatures.

  19. Comparative proteomic and metabolomic analyses reveal mechanisms of improved cold stress tolerance in bermudagrass (Cynodon dactylon (L.) Pers.) by exogenous calcium.

    Science.gov (United States)

    Shi, Haitao; Ye, Tiantian; Zhong, Bao; Liu, Xun; Chan, Zhulong

    2014-11-01

    As an important second messenger, calcium is involved in plant cold stress response, including chilling (stress tolerances, while ethylene glycol-bis-(β-aminoethyl) ether-N,N,N,N-tetraacetic acid (EGTA) reversed CaCl2 effects in bermudagrass (Cynodon dactylon (L.) Pers.). Physiological analyses showed that CaCl2 treatment alleviated the reactive oxygen species (ROS) burst and cell damage triggered by chilling stress, via activating antioxidant enzymes, non-enzymatic glutathione antioxidant pool, while EGTA treatment had the opposite effects. Additionally, comparative proteomic analysis identified 51 differentially expressed proteins that were enriched in redox, tricarboxylicacid cycle, glycolysis, photosynthesis, oxidative pentose phosphate pathway, and amino acid metabolisms. Consistently, 42 metabolites including amino acids, organic acids, sugars, and sugar alcohols were regulated by CaCl2 treatment under control and cold stress conditions, further confirming the common modulation of CaCl2 treatment in carbon metabolites and amino acid metabolism. Taken together, this study reported first evidence of the essential and protective roles of endogenous and exogenous calcium in bermudagrass response to cold stress, partially via activation of the antioxidants and modulation of several differentially expressed proteins and metabolic homeostasis in the process of cold acclimation. © 2014 Institute of Botany, Chinese Academy of Sciences.

  20. Influence of air flow on the performance of a dry powder inhaler using computational and experimental analyses.

    Science.gov (United States)

    Coates, Matthew S; Chan, Hak-Kim; Fletcher, David F; Raper, Judy A

    2005-09-01

    The aims of the study are to analyze the influence of air flow on the overall performance of a dry powder inhaler (Aerolizer and to provide an initial quantification of the flow turbulence levels and particle impaction velocities that maximized the inhaler dispersion performance. Computational fluid dynamics (CFD) analysis of the flow field in the Aerolizer, in conjunction with experimental dispersions of mannitol powder using a multistage liquid impinger, was used to determine how the inhaler dispersion performance varied as the device flow rate was increased. Both the powder dispersion and throat deposition were increased with air flow. The capsule retention was decreased with flow, whereas the device retention first increased then decreased with flow. The optimal inhaler performance was found at 65 l min(-1) showing a high fine particle fraction (FPF) of 63 wt.% with low throat deposition (9.0 wt.%) and capsule retention (4.3 wt.%). Computational fluid dynamics analysis showed that at the critical flow rate of 65 l min(-1), the volume-averaged integral scale strain rate (ISSR) was 5,400 s(-1), and the average particle impaction velocities were 12.7 and 19.0 m s(-1) at the inhaler base and grid, respectively. Correlations between the device flow rate and (a) the amount of throat deposition and (b) the capsule emptying times were also developed. The use of CFD has provided further insight into the effect of air flow on the performance of the Aerolizer. The approach of using CFD coupled with powder dispersion is readily applicable to other dry powder inhalers (DPIs) to help better understand their performance optimization.

  1. Improved solubility and bioactivity of theophylline (a bronchodilator drug) through its new nitrate salt analysed by experimental and theoretical approaches

    Science.gov (United States)

    Mary Novena, L.; Suresh Kumar, S.; Athimoolam, S.

    2016-07-01

    Synthesis, crystal structure, vibrational spectroscopy, quantum chemical studies and biological activity of the new semi organic compound, Theophyllinium Nitrate [C7H9N4 O2)+. (NO3)-], are reported here. Crystals of Theophyllinium nitrate (TN) were grown by slow solvent evaporation technique. The crystal packing is dominated by N-H···O intermolecular hydrogen bonds. The cations and anions are aggregated almost parallel leading to a lamellar structure. This molecular aggregation features two alternate hydrogen bonded chain C22(8) and C21(6) motifs. Further, a bifurcated ring R12(4) motifs is also seen. This aggregated molecular sheets are parallel to (2 bar 06) and (20 6 bar) planes of the crystal. The solubility test is carried out to enhance the physico-chemical activity of the compound. The atomic charge distribution on different atoms of TN has been calculated by Mulliken charge analysis. A detailed interpretation of FT-IR and FT-Raman spectra of TN show that most of the bands are matching between the experimental and theoretical methods. The strong intensity bands and shifting of bands due to intermolecular hydrogen bonds are also investigated. The NBO analysis is carried out to elucidate the stability of the molecule and charge delocalization within the molecule. The HOMO-LUMO analysis reveals molecular stability and chemical reactivity of the present compound. Also, the compound was examined for its antibacterial activity and found to exhibit notable activity against Pseudomonas aeruginosa. This shows that the present compound is a good candidate for the antimicrobial agent apart from its inherent Bronchodilator drug property. Hence, the new compound (TN) may be a good alternative for patients with Chronic Obstructive Pulmonary Disease (COPD) and bacterial infections.

  2. Conversations between scientists and the public in radio phone-ins: an experimental approach to analyse public perception of science

    Directory of Open Access Journals (Sweden)

    Merzagora Matteo

    2002-03-01

    Full Text Available “Il ciclotrone” is the weekly science programme of “Radio Popolare - Popolare Network”, the most important independent news radio network in Italy, based in Milan. During the last 12 years, once or twice a month listeners have been able to directly ask questions to the guest scientists in the studios, or to express their point of view on some controversial scientific issue. Among mass-media, the radio has several characteristics which tend to enhance the sense of friendliness and belonging - essential to any true communication. Phone-ins at Radio Popolare are not filtered; regular and occasional listeners are used to communicate with or through the radio, and in doing so they contribute to the sense of spontaneity which characterise the programmes. During “Il ciclotrone”, very often the ''anchor'' tends to disappear, and phone-ins become a lively conversation between the scientists and the public (whose members seldom agree with each other. In this presentation, phone-ins on science - over the years they involved internationally famous scientists (such as Lewontin, Damasio, Amaldi, Rotblat, Di Chiara, …, and less well-known but reputed Italian researchers - are analysed in terms of their capabilities of providing a tool to understand public perception of science. Moreover, the authors believe that science journalism shouldn't only inform or educate the public on the work of scientists, but also inform or educate the scientists on how their work is perceived. Indeed, scientists seldom have a chance to hear the criticism (positive or negative of a large, unselected audience and to have a first-hand grasp of public feelings concerning their work.

  3. An Experimental Investigation into Additive Manufacturing-Induced Residual Stresses in 316L Stainless Steel

    Science.gov (United States)

    Wu, Amanda S.; Brown, Donald W.; Kumar, Mukul; Gallegos, Gilbert F.; King, Wayne E.

    2014-12-01

    Additive manufacturing (AM) technology provides unique opportunities for producing net-shape geometries at the macroscale through microscale processing. This level of control presents inherent trade-offs necessitating the establishment of quality controls aimed at minimizing undesirable properties, such as porosity and residual stresses. Here, we perform a parametric study into the effects of laser scanning pattern, power, speed, and build direction in powder bed fusion AM on residual stress. In an effort to better understand the factors influencing macroscale residual stresses, a destructive surface residual stress measurement technique (digital image correlation in conjunction with build plate removal and sectioning) has been coupled with a nondestructive volumetric evaluation method ( i.e., neutron diffraction). Good agreement between the two measurement techniques is observed. Furthermore, a reduction in residual stress is obtained by decreasing scan island size, increasing island to wall rotation to 45 deg, and increasing applied energy per unit length (laser power/speed). Neutron diffraction measurements reveal that, while in-plane residual stresses are affected by scan island rotation, axial residual stresses are unchanged. We attribute this in-plane behavior to misalignment between the greatest thermal stresses (scan direction) and largest part dimension.

  4. Cortisol reactivity to experimentally manipulated psychosocial stress in young adults at varied risk for depression.

    Science.gov (United States)

    Morris, Matthew C; Rao, Uma; Wang, Lily; Garber, Judy

    2014-01-01

    This study examined cortisol and affective reactivity to a psychosocial stress task in 102 young adults who varied in risk for depression (56 remitted depressed, 46 never depressed). Participants were randomly assigned to either a stress (i.e., social-evaluative threat) or control (i.e., no social-evaluative threat) condition. For never-depressed individuals, cortisol responses were significantly greater in the stress compared to the control condition. Moreover, cortisol responses were significantly greater for never-depressed than remitted-depressed individuals in the stress condition. For individuals with a history of depression, cortisol responses did not differ significantly between the stress and control conditions. Negative affective reactivity also was higher for never depressed, but not remitted depressed, individuals in the stress compared to the control condition. Moreover, cortisol responses were inversely related to negative affect during the recovery phase in both stress and control conditions. Findings indicate the lack of a robust cortisol response to social evaluation stress among remitted-depressed individuals as compared to that of never-depressed controls. Future studies should investigate unique and interactive links between these hypothalamic-pituitary-adrenal and affective reactivity alterations and risk for subsequent depressive episodes. © 2013 Wiley Periodicals, Inc.

  5. Experimental Aspects of the Study of Stress Generating Mechanisms in Silicon Sheet Growth

    Science.gov (United States)

    Kaleja, J. P.; Bell, R. O.

    1984-01-01

    Stress analysis on silicon sheet grown at high speeds of the growth behavior and defect structure of 10 cm wide ribbon produced by the EFG technique was examined. The ribbon temperature field, the high temperature creep response of silicon, and approaches to measurement of the residual stress are investigated.

  6. Experimental aspects of the study of stress generating mechanisms in silicon sheet growth

    Science.gov (United States)

    Kaleja, J. P.; Bell, R. O.

    1984-04-01

    Stress analysis on silicon sheet grown at high speeds of the growth behavior and defect structure of 10 cm wide ribbon produced by the EFG technique was examined. The ribbon temperature field, the high temperature creep response of silicon, and approaches to measurement of the residual stress are investigated.

  7. A Refined Higher-Order Hybrid Stress Quadrilateral Element for Free Vibration and Buckling Analyses of Reissner-Mindlin Plates

    Directory of Open Access Journals (Sweden)

    Tan Li

    2017-01-01

    Full Text Available This paper is devoted to develop a new 8-node higher-order hybrid stress element (QH8 for free vibration and buckling analysis based on the Mindlin/Reissner plate theory. In particular, a simple explicit expression of a refine method with an adjustable constant is introduced to improve the accuracy of the analysis. A combined mass matrix for natural frequency analysis and a combined geometric stiffness matrix for buckling analysis are obtained using the refined method. It is noted that numerical examples are presented to show the validity and efficiency of the present element for free vibration and buckling analysis of plates. Furthermore, satisfactory accuracy for thin and moderately thick plates is obtained and it is free from shear locking for thin plate analysis and can pass the nonzero shear stress patch test.

  8. Impact of Laser Irradiation on Brain Resistance to Postresuscitative Emotional Stresses (Experimental Study

    Directory of Open Access Journals (Sweden)

    V. V. Moroz

    2009-01-01

    Full Text Available The paper shows how to solve the urgent problem of posthypoxic rat brain resistance to emotional stress. An hour hypovolemic hypotension (mean blood pressure 45 mm Hg served as a model of a terminal condition. The integra-tive activity of the rat brain was evaluated by the elevated cross labyrinth test. Emotional stress was induced by confrontation between the falsely operated and antihypertensive rats within 30 postischemic days. Laser irradiation was carried out an hour after blood reinfusion. Laser irradiation used before emotional stress was shown to increase the resistance of the posthypoxic rat brain to emotional stress and to prevent the development of depression-like states in the late periods after resuscitation. Key words: blood loss, postresuscitative period, emotional stress, laser irradiation.

  9. NUMERICAL AND EXPERIMENTAL ANALYSIS OF RESIDUAL STRESSES GENERATED DURING HARDENING OFAISI 4140 BAR

    Directory of Open Access Journals (Sweden)

    Edwan Anderson Ariza Echeverri

    2012-09-01

    Full Text Available The aim of this work is to analyze the distribution of residual stresses resulting from the combination of volumetric changes due to heat gradients and phase changes occurring during the quenching process of an AISI/SAE 4140 steel cylinder. The mathematical model used for this objective is the AC3 modeling software of thermal treatments (transformation curves, cooling curves and microstructure, whose results were input in an finite element model, considering thermalmechanical coupling and non-linear elastic-plastic behavior, aiming the assessment of residual stresses in quenched 4140 steel cylinders. The observed microstructure confirms quantitatively and qualitatively the previsions of the AC3 Software. The results of the modeling are compared with the residual stresses measurements made using X-Ray diffraction techniques. The finite element numerical simulation shows the existence of 350 MPa compressive residual stresses in the surface region and indicates that the most significant stresses are tangential.

  10. Experimental Study of Residual Stresses in Metal Parts Obtained by Selective Laser Melting

    Science.gov (United States)

    Protasov, C. E.; Safronov, V. A.; Kotoban, D. V.; Gusarov, A. V.

    High local temperature gradients occur at additive manufacturing by selective laser melting of powder. This gives rise to undesirable residual stresses, deformations, and cracks. To understand how to control the formation of the residual stresses, a reliable method is necessary for measuring their distribution in the fabricated part. It is proposed to cut the part into thin plates and to reconstruct the residual stresses from the measured deformation of the plates. This method is tested on beams with square cross-section built from stainless steel. The beams were cut by electrical discharge machining and chemically etched. The obtained stress profile in vertical transversal direction slightly increases from the top to the bottom of the beam. This dependency is confirmed by numerical modeling. The measured stress profile agrees with the known results by other authors.

  11. An analytical and experimental stress analysis of a practical mode II fracture-test specimen

    Science.gov (United States)

    Chisholm, D. B.; Jones, D. L.

    1975-01-01

    A boundary collocation method has been employed to determine the Mode II stress intensity factors for a pair of through-the-thickness edge cracks in a finite isotropic plate. An elastostatic analysis has been carried out in terms of the complete Williams stress function employing both even and odd components. The results of the numerical analysis were verified by a two-step procedure whereby the symmetric and antisymmetric portions of the solution were independently compared with existing solutions. The complete solution was verified by comparison with a photoelastic analysis. A compact shear specimen (CSS) of Hysol epoxy resin was loaded in a photoelastic experiment designed to study the isochromatic fringe patterns resulting from the Mode II crack tip stress distribution. The experiment verified that a pure Mode II stress distribution existed in the neighborhood of the crack tips and confirmed the accuracy of the boundary collocation solution for the Mode II stress intensity factors.

  12. Analyses of freshwater stress with a couple ground and surface water model in the Pra Basin, Ghana

    Science.gov (United States)

    Owusu, George; Owusu, Alex B.; Amankwaa, Ebenezer Forkuo; Eshun, Fatima

    2017-03-01

    The optimal management of water resources requires that the collected hydrogeological, meteorological, and spatial data be simulated and analyzed with appropriate models. In this study, a catchment-scale distributed hydrological modeling approach is applied to simulate water stress for the years 2000 and 2050 in a data scarce Pra Basin, Ghana. The model is divided into three parts: The first computes surface and groundwater availability as well as shallow and deep groundwater residence times by using POLFLOW model; the second extends the POLFLOW model with water demand (Domestic, Industrial and Agricultural) model; and the third part involves modeling water stress indices—from the ratio of water demand to water availability—for every part of the basin. On water availability, the model estimated long-term annual Pra river discharge at the outflow point of the basin, Deboase, to be 198 m3/s as against long-term average measurement of 197 m3/s. Moreover, the relationship between simulated discharge and measured discharge at 9 substations in the basin scored Nash-Sutcliffe model efficiency coefficient of 0.98, which indicates that the model estimation is in agreement with the long-term measured discharge. The estimated total water demand significantly increases from 959,049,096 m3/year in 2000 to 3,749,559,019 m3/year in 2050 ( p < 0.05). The number of districts experiencing water stress significantly increases ( p = 0.00044) from 8 in 2000 to 21 out of 35 by the year 2050. This study will among other things help the stakeholders in water resources management to identify and manage water stress areas in the basin.

  13. The influence of trial order on learning from reward vs. punishment in a probabilistic categorization task: experimental and computational analyses.

    Science.gov (United States)

    Moustafa, Ahmed A; Gluck, Mark A; Herzallah, Mohammad M; Myers, Catherine E

    2015-01-01

    Previous research has shown that trial ordering affects cognitive performance, but this has not been tested using category-learning tasks that differentiate learning from reward and punishment. Here, we tested two groups of healthy young adults using a probabilistic category learning task of reward and punishment in which there are two types of trials (reward, punishment) and three possible outcomes: (1) positive feedback for correct responses in reward trials; (2) negative feedback for incorrect responses in punishment trials; and (3) no feedback for incorrect answers in reward trials and correct answers in punishment trials. Hence, trials without feedback are ambiguous, and may represent either successful avoidance of punishment or failure to obtain reward. In Experiment 1, the first group of subjects received an intermixed task in which reward and punishment trials were presented in the same block, as a standard baseline task. In Experiment 2, a second group completed the separated task, in which reward and punishment trials were presented in separate blocks. Additionally, in order to understand the mechanisms underlying performance in the experimental conditions, we fit individual data using a Q-learning model. Results from Experiment 1 show that subjects who completed the intermixed task paradoxically valued the no-feedback outcome as a reinforcer when it occurred on reinforcement-based trials, and as a punisher when it occurred on punishment-based trials. This is supported by patterns of empirical responding, where subjects showed more win-stay behavior following an explicit reward than following an omission of punishment, and more lose-shift behavior following an explicit punisher than following an omission of reward. In Experiment 2, results showed similar performance whether subjects received reward-based or punishment-based trials first. However, when the Q-learning model was applied to these data, there were differences between subjects in the reward

  14. Genome-Wide Identification and Expression Analyses of Aquaporin Gene Family during Development and Abiotic Stress in Banana.

    Science.gov (United States)

    Hu, Wei; Hou, Xiaowan; Huang, Chao; Yan, Yan; Tie, Weiwei; Ding, Zehong; Wei, Yunxie; Liu, Juhua; Miao, Hongxia; Lu, Zhiwei; Li, Meiying; Xu, Biyu; Jin, Zhiqiang

    2015-08-20

    Aquaporins (AQPs) function to selectively control the flow of water and other small molecules through biological membranes, playing crucial roles in various biological processes. However, little information is available on the AQP gene family in bananas. In this study, we identified 47 banana AQP genes based on the banana genome sequence. Evolutionary analysis of AQPs from banana, Arabidopsis, poplar, and rice indicated that banana AQPs (MaAQPs) were clustered into four subfamilies. Conserved motif analysis showed that all banana AQPs contained the typical AQP-like or major intrinsic protein (MIP) domain. Gene structure analysis suggested the majority of MaAQPs had two to four introns with a highly specific number and length for each subfamily. Expression analysis of MaAQP genes during fruit development and postharvest ripening showed that some MaAQP genes exhibited high expression levels during these stages, indicating the involvement of MaAQP genes in banana fruit development and ripening. Additionally, some MaAQP genes showed strong induction after stress treatment and therefore, may represent potential candidates for improving banana resistance to abiotic stress. Taken together, this study identified some excellent tissue-specific, fruit development- and ripening-dependent, and abiotic stress-responsive candidate MaAQP genes, which could lay a solid foundation for genetic improvement of banana cultivars.

  15. Identification and expression analyses of WRKY genes reveal their involvement in growth and abiotic stress response in watermelon (Citrullus lanatus.

    Directory of Open Access Journals (Sweden)

    Xiaozhen Yang

    Full Text Available Despite identification of WRKY family genes in numerous plant species, a little is known about WRKY genes in watermelon, one of the most economically important fruit crops around the world. Here, we identified a total of 63 putative WRKY genes in watermelon and classified them into three major groups (I-III and five subgroups (IIa-IIe in group II. The structure analysis indicated that ClWRKYs with different WRKY domains or motifs may play different roles by regulating respective target genes. The expressions of ClWRKYs in different tissues indicate that they are involved in various tissue growth and development. Furthermore, the diverse responses of ClWRKYs to drought, salt, or cold stress suggest that they positively or negatively affect plant tolerance to various abiotic stresses. In addition, the altered expression patterns of ClWRKYs in response to phytohormones such as, ABA, SA, MeJA, and ETH, imply the occurrence of complex cross-talks between ClWRKYs and plant hormone signals in regulating plant physiological and biological processes. Taken together, our findings provide valuable clues to further explore the function and regulatory mechanisms of ClWRKY genes in watermelon growth, development, and adaption to environmental stresses.

  16. Fracture and Stress Evolution on Europa: New Insights Into Fracture Interpretation and Ice Thickness Estimates Using Fracture Mechanics Analyses

    Science.gov (United States)

    Kattenhorn, Simon

    2004-01-01

    The work completed during the funding period has provided many important insights into fracturing behavior in Europa's ice shell. It has been determined that fracturing through time is likely to have been controlled by the effects of nonsynchronous rotation stresses and that as much as 720 deg of said rotation may have occurred during the visible geologic history. It has been determined that there are at least two distinct styles of strike-slip faulting and that their mutual evolutionary styles are likely to have been different, with one involving a significant dilational component during shear motion. It has been determined that secondary fracturing in perturbed stress fields adjacent to older structures such as faults is a prevalent process on Europa. It has been determined that cycloidal ridges are likely to experience shear stresses along the existing segment portions as they propagate, which affects propagation direction and ultimately induces tailcracking at the segment tip than then initiates a new cycle of cycloid segment growth. Finally, it has been established that mechanical methods (e.g., flexure analysis) can be used to determine the elastic thickness of the ice shell, which, although probably only several km thick, is likely to be spatially variable, being thinner under bands but thicker under ridged plains terrain.

  17. Genome-Wide Identification of R2R3-MYB Genes and Expression Analyses During Abiotic Stress in Gossypium raimondii.

    Science.gov (United States)

    He, Qiuling; Jones, Don C; Li, Wei; Xie, Fuliang; Ma, Jun; Sun, Runrun; Wang, Qinglian; Zhu, Shuijin; Zhang, Baohong

    2016-03-24

    The R2R3-MYB is one of the largest families of transcription factors, which have been implicated in multiple biological processes. There is great diversity in the number of R2R3-MYB genes in different plants. However, there is no report on genome-wide characterization of this gene family in cotton. In the present study, a total of 205 putative R2R3-MYB genes were identified in cotton D genome (Gossypium raimondii), that are much larger than that found in other cash crops with fully sequenced genomes. These GrMYBs were classified into 13 groups with the R2R3-MYB genes from Arabidopsis and rice. The amino acid motifs and phylogenetic tree were predicted and analyzed. The sequences of GrMYBs were distributed across 13 chromosomes at various densities. The results showed that the expansion of the G. Raimondii R2R3-MYB family was mainly attributable to whole genome duplication and segmental duplication. Moreover, the expression pattern of 52 selected GrMYBs and 46 GaMYBs were tested in roots and leaves under different abiotic stress conditions. The results revealed that the MYB genes in cotton were differentially expressed under salt and drought stress treatment. Our results will be useful for determining the precise role of the MYB genes during stress responses with crop improvement.

  18. What effect does regular exercise have on oxidative stress in people with Down syndrome? A systematic review with meta-analyses.

    Science.gov (United States)

    Shields, Nora; Downs, Jenny; de Haan, Judy B; Taylor, Nicholas F; Torr, Jennifer; Fernhall, Bo; Kingsley, Michael; Mnatzaganian, George; Leonard, Helen

    2017-10-19

    What effect does regular exercise have on oxidative stress in people with Down syndrome? Systematic review with meta-analyses. A systematic review with meta-analyses was conducted. Six databases were searched from inception until August 2017. Studies where included if participants with Down syndrome (any age) had completed an exercise program of at least 6 weeks duration and at least one biomarker measured the generation or removal of reactive oxidative species. Data were extracted using a customised form. Risk of bias was assessed using the Cochrane Collaboration⿿s Risk of Bias assessment tool. Effect sizes were calculated and meta-analyses completed for clinically homogeneous data using a random effects model. Seven studies (11 articles) involving 144 inactive participants investigated the effect of moderate intensity aerobic exercise. No pattern emerged for how most biomarkers responded with non-significant pooled effect sizes and high levels of heterogeneity observed. The exception was catalase which increased significantly after exercise (standardised mean difference 0.39, 95%CI 0.04⿿0.75; I2 15%). Available studies were at high risk of bias. Two of five studies that measured more than one biomarker reported a decrease in oxidative stress with increased antioxidant activity after exercise but the other three (including one small randomised controlled trial) reported increased oxidative stress with variable change in antioxidant activity. There remains uncertainty about the effect of exercise on oxidative stress in people with Down syndrome. PROSPERO CRD42016048492. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  19. Chronic stress moderates the impact of social exclusion on pain tolerance: an experimental investigation

    National Research Council Canada - National Science Library

    Pieritz K; Schäfer SJ; Strahler J; Rief W; Euteneuer F

    2017-01-01

    ... (ie, heat pain tolerance) and a sensory component of pain (ie, heat pain intensity). Whether a potential effect may be moderated by chronic life stress, social status, or social support was further examined...

  20. Weathering the storm: parental effort and experimental manipulation of stress hormones predict brood survival

    NARCIS (Netherlands)

    Ouyang, JQ; Lendvai, AZ; Dakin, R.; Domalik, AD; Fasanello, VJ; Vassallo, BG; Haussmann, MF; Moore, IT; Bonier, F.

    2015-01-01

    BACKGROUND:Unpredictable and inclement weather is increasing in strength and frequency, challenging organisms to respond adaptively. One way in which animals respond to environmental challenges is through the secretion of glucocorticoid stress hormones. These hormones mobilize energy stores and

  1. Graphite nodules and local residual stresses in ductile iron: Thermo-mechanical modelingand experimental validation

    DEFF Research Database (Denmark)

    Andriollo, Tito

    Ductile iron is nowadays widely used in key industrial sectors like off-shore, transport and energy production, accounting for as much as 25 % of the total casting production in the world. It is well known that ductile iron parts, depending on their size, may contain residual stresses developing...... stages of the manufacturing process are simulated numerically, accounting for the different thermal expansion of the nodules and of the matrix during both the eutectoid transformation and the subsequent cooling to room temperature. The results show the formation of significant residual stresses...... the theoretical predictions that local stresses up to approximately half the macroscopic yield strength may remain in the ductile iron microstructure after manufacturing. Needless to say, this new type of residual stresses is expected to play an important role in determining the properties of ductile iron...

  2. Mechanisms by which Stress Affects the Experimental and Clinical Inflammatory Bowel Disease (IBD): Role of Brain-Gut Axis.

    Science.gov (United States)

    Brzozowski, Bartosz; Mazur-Bialy, Agnieszka; Pajdo, Robert; Kwiecien, Slawomir; Bilski, Jan; Zwolinska-Wcislo, Malgorzata; Mach, Tomasz; Brzozowski, Tomasz

    2016-01-01

    Stress of different origin is known to alter so called "braingut axis" and contributes to a broad array of gastrointestinal disorders including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and other functional gastrointestinal diseases. The stressful situations and various stressors including psychosocial events, heat, hypo- and hyperthermia may worsen the course of IBD via unknown mechanism. The aims of this paper were to provide an overview of experimental and clinical evidences that stress activates the brain-gut axis which results in a mucosal mast cells activation and an increase in the production of proinflammatory cytokines and other endocrine and humoral mediators. Research and online content related to effects of stress on lower bowel disorders are reviewed and most important mechanisms are delineated. Brain conveys the neural, endocrine and circulatory messages to the gut via brain-gut axis reflecting changes in corticotrophin releasing hormone, mast cells activity, neurotransmission at the autonomic nerves system and intestinal barrier function all affecting the pathogenesis of animal colitis and human IBD. Stress triggers the hypothalamus-pituitary axis and the activation of the autonomic nervous system, an increase in cortisol levels and proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-8, interleukin-1beta and interleukin-6. The acute or chronic stress enhances the intestinal permeability weakening of the tight junctions and increasing bacterial translocation into the intestinal wall. An increased microbial load in the colonic tissue, excessive cytokine release and a partially blunted immune reactivity in response to stress result in its negative impact on IBD.

  3. Experimental and theoretical studies into the stress-strain state of the purlin supported by sandwich panels

    Directory of Open Access Journals (Sweden)

    Danilov Aleksandr Ivanovich

    2014-12-01

    Full Text Available In the article, the co-authors analyze the findings of the experimental and theoretical studies into the real behaviour of a thin-walled cold-formed purlin as part of the roof structure made of sandwich panels. The roof structure fragment was tested; displacements and stresses, that the purlin was exposed to, were identified in respect of each loading increment. NASTRAN software was employed to perform the numerical analysis of the roof structure, pre-exposed to experimental tests, in the geometrically and physically non-linear setting. The finite element model, generated as a result (the numerical analysis pattern, is sufficiently well-set, given the proposed grid of elements, and it ensures reasonably trustworthy results. The diagrams describing the stress/displacement to the load ratio and obtained numerically are consistent with those generated experimentally. The gap between the critical loading values reaches 4%. Analytical and experimental findings demonstrate their close conformity, and this fact may justify the application of the numerical model, generated within the framework of this research project, in the course of any further research actions. The co-authors have identified that the exhaustion of the bearing capacity occurs due to the loss of the buckling resistance as a result of the lateral torsional buckling.

  4. The down-stress transition from cluster to cone fabrics in experimentally deformed ice

    Science.gov (United States)

    Qi, Chao; Goldsby, David L.; Prior, David J.

    2017-08-01

    During plastic deformation of polycrystalline ice 1h, ice crystals become crystallographically aligned due to dislocation glide, primarily on the basal slip system. Such crystallographic preferred orientation (CPO) introduces a viscous anisotropy in ice, and thus strongly influences the kinematics of the flow of glaciers and ice sheets. Two key mechanisms exert different controls on CPO. In axial compression, recrystallization dominated by lattice rotation yields a cluster of c-axes parallel to compression, and recrystallization dominated by grain boundary migration (GBM) yields a cone-shaped distribution of c-axes with the cone axis parallel to compression. The transition between these dominant mechanisms of CPO formation has not been well quantified. In this study, we explore how this transition varies with stress. Ice deformation experiments were conducted using a high-pressure, gas-medium apparatus to prevent fracturing of samples at relatively high stresses. Samples were deformed in uniaxial compression at a temperature of ∼-10 °C and a confining pressure of 10 MPa. Fabricated ice samples with starting average grain sizes of either ∼0.23 mm or ∼0.63 mm were each deformed to an axial strain of ∼0.2 at a nominally constant strain rate in the range 1.2 ×10-6 to 2.4 ×10-4 s-1, yielding flow stresses of 1.17 to 4.31 MPa. High-quality electron backscatter diffraction reveal the grain size, shape, subgrain structure, and CPOs formed at different stresses. All deformed samples have strong, non-random CPOs with c-axes concentrated in cones. The cone angle and CPO strength are observed to decrease with increasing stress. As stress increases, the fraction of grains with highly curved or lobate grain boundaries decreases and the fraction of polygonal grains with straight grain boundaries increases. Based on these observations, we propose that a transition in the dominant mechanism of CPO formation occurs with increasing stress, from GBM, which consumes grains

  5. IMPROVEMENT IN OXIDATIVE STRESS AFTER DUODENOJEJUNOSTOMY IN AN EXPERIMENTAL MODEL OF TYPE 2 DIABETES MELLITUS

    OpenAIRE

    WIETZYCOSKI, Cacio Ricardo; MARCHESINI, João Caetano Dallegrave; AL-THEMYAT, Sultan; MEYER, Fabiola Shons; TRINDADE, Manoel Roberto Maciel

    2016-01-01

    ABSTRACT Background: Type 2 Diabetes Mellitus is a multifactorial syndrome with severe complications. Oxidative stress is accepted as a causal factor of chronic complications Aim: To demonstrate alterations in oxidative stress after metabolic surgery. Methods: Twenty-four 2-day-old Wistar rats were used. In 16, Type 2 Diabetes Mellitus was induced by 100 mg/kg streptozotocin injection. The development of diabetes was confirmed after 10 weeks using an oral glucose tolerance test. Eight diab...

  6. Characterization and analyses on micro-hardness, residual stress and microstructure in laser cladding coating of 316L stainless steel subjected to massive LSP treatment

    Energy Technology Data Exchange (ETDEWEB)

    Luo, K.Y.; Jing, X.; Sheng, J. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Sun, G.F. [School of Mechanical Engineering, Southeast University, Nanjing, 211189 (China); Yan, Z. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Lu, J.Z., E-mail: jzlu@ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China)

    2016-07-15

    The effects of massive laser shock peening (LSP) treatment on micro-hardness, residual stress and microstructure in four different zones of laser cladding coating was investigated. Furthermore, micro-hardness curves and residual stress distributions with and without massive LSP treatment were presented and compared, and typical microstructure in different zones of both coatings were characterized by transmission electron microscope (TEM) and cross-sectional optical microscope (OM) observations. Results and analyses showed that massive LSP treatment had an important influence on micro-hardness and residual stress of the cladding coating. Special attempt was made to the effects of massive LSP treatment on microstructure in three zones of the cladding coating. In addition, the underlying mechanism of massive LSP treatment on microstructure and mechanical properties of the cladding coating was revealed clearly. - Highlights: • Micro-hardness and residual stress curves of both coatings were presented and compared. • Typical microstructure in different zones of both coatings were characterized and analyzed. • LSP causes increased micro-activities, and induces plastic deformation layer in three zones. • Underlying mechanism of LSP on mechanical properties of cladding coating was revealed.

  7. Proteomic analyses bring new insights into the effect of a dark stress on lipid biosynthesis in Phaeodactylum tricornutum

    Science.gov (United States)

    Bai, Xiaocui; Song, Hao; Lavoie, Michel; Zhu, Kun; Su, Yiyuan; Ye, Hanqi; Chen, Si; Fu, Zhengwei; Qian, Haifeng

    2016-05-01

    Microalgae biosynthesize high amount of lipids and show high potential for renewable biodiesel production. However, the production cost of microalgae-derived biodiesel hampers large-scale biodiesel commercialization and new strategies for increasing lipid production efficiency from algae are urgently needed. Here we submitted the marine algae Phaeodactylum tricornutum to a 4-day dark stress, a condition increasing by 2.3-fold the total lipid cell quotas, and studied the cellular mechanisms leading to lipid accumulation using a combination of physiological, proteomic (iTRAQ) and genomic (qRT-PCR) approaches. Our results show that the expression of proteins in the biochemical pathways of glycolysis and the synthesis of fatty acids were induced in the dark, potentially using excess carbon and nitrogen produced from protein breakdown. Treatment of algae in the dark, which increased algal lipid cell quotas at low cost, combined with optimal growth treatment could help optimizing biodiesel production.

  8. Approach to Operational Experimental Estimation of Static Stresses of Elements of Mechanical Structures

    Science.gov (United States)

    Sedov, A. V.; Kalinchuk, V. V.; Bocharova, O. V.

    2018-01-01

    The evaluation of static stresses and strength of units and components is a crucial task for increasing reliability in the operation of vehicles and equipment, to prevent emergencies, especially in structures made of metal and composite materials. At the stage of creation and commissioning of structures to control the quality of manufacturing of individual elements and components, diagnostic control methods are widely used. They are acoustic, ultrasonic, X-ray, radiation methods and others. The using of these methods to control the residual life and the degree of static stresses of units and parts during operation is fraught with great difficulties both in methodology and in instrumentation. In this paper, the authors propose an effective approach of operative control of the degree of static stresses of units and parts of mechanical structures which are in working condition, based on recording the changing in the surface wave properties of a system consisting of a sensor and a controlled environment (unit, part). The proposed approach of low-frequency diagnostics of static stresses presupposes a new adaptive-spectral analysis of a surface wave created by external action (impact). It is possible to estimate implicit stresses of structures in the experiment due to this approach.

  9. Experimental study on seismic behavior of circular RC columns strengthened with pre-stressed FRP strips

    Science.gov (United States)

    Zhou, Changdong; Lu, Xilin; Li, Hui; Tian, Teng

    2013-12-01

    Bonding fiber reinforced polymer (FRP) has been commonly used to improve the seismic behavior of circular reinforced concrete (RC) columns in engineering practice. However, FRP jackets have a significant stress hysteresis effect in this strengthening method, and pre-tensioning the FRP can overcome this problem. This paper presents test results of 25 circular RC columns strengthened with pre-stressed FRP strips under low cyclic loading. The pre-stressing of the FRP strips, types of FRP strips and longitudinal reinforcement, axial load ratio, pre-damage degree and surface treatments of the specimens are considered as the primary factors in the tests. According to the failure modes and hysteresis curves of the specimens, these factors are analyzed to investigate their effect on bearing capacity, ductility, hysteretic behavior, energy dissipation capacity and other important seismic behaviors. The results show that the initial lateral confined stress provided by pre-stressed FRP strips can effectively inhibit the emergence and development of diagonal shear cracks, and change the failure modes of specimens from brittle shear failure to bending or bending-shear failure with better ductility. As a result, the bearing capacity, ductility, energy dissipation capacity and deformation capacity of the strengthened specimens are all significantly improved.

  10. Caffeic acid attenuates oxidative stress, learning and memory deficit in intra-cerebroventricular streptozotocin induced experimental dementia in rats.

    Science.gov (United States)

    Deshmukh, Rahul; Kaundal, Madhu; Bansal, Vikas; Samardeep

    2016-07-01

    Oxidative stress has been implicated in cognitive decline as seen during normal aging and in sporadic Alzheimer's disease (AD). Caffeic acid, a polyphenolic compound, has been reported to possess potent antioxidant and neuroprotective properties. The role of caffeic acid in experimental dementia is not fully understood. Thus the present study was designed to investigate the therapeutic potential of caffeic acid in streptozotocin (STZ)-induced experimental dementia of Alzheimer's type in rats. Streptozotocin (STZ) was administered intracerebroventrically (ICV) on day 1 and 3 (3mg/kg, ICV bilaterally) in Wistar rats. Caffeic acid was administered (10, 20 and 40mg/kg/day p.o.) 1h following STZ infusion upto 21st day. Morris water maze and object recognition task were used to assess learning and memory in rats. Terminally, acetylcholinesterase (AChE) activity and the levels of oxido-nitrosative stress markers were determined in cortical and hippocampal brain regions of rats. STZ produced significant (plearning and memory impairment, oxido-nitrosative stress and cholinergic deficit in rats. Whereas, caffeic acid treatment significantly (p<0.001) and dose dependently attenuated STZ induced behavioral and biochemical abnormalities in rats. The observed cognitive improvement following caffeic acid in STZ treated rats may be due to its antioxidant activity and restoration of cholinergic functions. Our results suggest the therapeutic potential of caffeic acid in cognitive disorders such as AD. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Changes in pain catastrophizing predict later changes in fibromyalgia clinical and experimental pain report: cross-lagged panel analyses of dispositional and situational catastrophizing.

    Science.gov (United States)

    Campbell, Claudia M; McCauley, Lea; Bounds, Sara C; Mathur, Vani A; Conn, Lora; Simango, Mpepera; Edwards, Robert R; Fontaine, Kevin R

    2012-10-25

    Fibromyalgia (FM), characterized by wide-spread diffuse pain and sensory abnormalities, is associated with elevated indices of distress and pain-related catastrophizing compared to both pain-free samples and those with chronic pain conditions. Catastrophizing is a pervasive negative mental set, and is a strong predictor of negative pain-related outcomes such as clinical pain intensity, and physical disability. Situational catastrophizing, measured in the context of experimentally-induced pain, is strongly related to enhanced pain sensitivity, a core aspect of the pathophysiology of fibromyalgia. However, little is known regarding the temporal course of the association between catastrophizing and pain-related "outcomes". Most studies involve only static assessments of pain and catastrophizing at a single time point, which provides little insight into the direction of the observed associations. We sought to investigate the temporal relationships between catastrophizing and indices of both clinical pain (substudy 1) and experimentally-induced pain (substudy 2) in a larger randomized controlled longitudinal trial. Fifty-seven patients with FM completed catastrophizing, depression, and pain questionnaires as well as laboratory cold pressor pain testing at baseline, post-intervention and three month follow-up during a lifestyle physical activity study. Cross-lagged panel analyses were used to address these temporal relationships. In substudy 1, analyses revealed that pre-to-post changes in dispositional catastrophizing ratings prospectively accounted for unique variance in subsequent post-to-follow-up changes in clinical pain ratings (p = 0.005), while pre-to-post changes in pain ratings did not account for unique variance in post-to-follow-up changes in catastrophizing ratings. An identical pattern was observed experimentally in substudy 2, with pre-to-post changes in situational catastrophizing ratings prospectively accounting for unique variance in subsequent post

  12. Stress and Corticosteroids Aggravate Morphological Changes in the Dentate Gyrus after Early-Life Experimental Febrile Seizures in Mice

    Directory of Open Access Journals (Sweden)

    Jolien S. van Campen

    2018-01-01

    Full Text Available Stress is the most frequently self-reported seizure precipitant in patients with epilepsy. Moreover, a relation between ear stress and epilepsy has been suggested. Although ear stress and stress hormones are known to influence seizure threshold in rodents, effects on the development of epilepsy (epileptogenesis are still unclear. Therefore, we studied the consequences of ear corticosteroid exposure for epileptogenesis, under highly controlled conditions in an animal model. Experimental febrile seizures (eFS were elicited in 10-day-old mice by warm-air induced hyperthermia, while a control group was exposed to a normothermic condition. In the following 2 weeks, mice received either seven corticosterone or vehicle injections or were left undisturbed. Specific measures indicative for epileptogenesis were examined at 25 days of age and compared with vehicle injected or untreated mice. We examined structural [neurogenesis, dendritic morphology, and mossy fiber sprouting (MFS] and functional (glutamatergic postsynaptic currents and long-term potentiation plasticity in the dentate gyrus (DG. We found that differences in DG morphology induced by eFS were aggravated by repetitive (mildly stressful vehicle injections and corticosterone exposure. In the injected groups, eFS were associated with decreases in neurogenesis, and increases in cell proliferation, dendritic length, and spine density. No group differences were found in MFS. Despite these changes in DG morphology, no effects of eFS were found on functional plasticity. We conclude that corticosterone exposure during early epileptogenesis elicited by eFS aggravates morphological, but not functional, changes in the DG, which partly supports the hypothesis that ear stress stimulates epileptogenesis.

  13. Development of a stress-mode sensitive viscoelastic constitutive relationship for asphalt concrete: experimental and numerical modeling

    Science.gov (United States)

    Karimi, Mohammad M.; Tabatabaee, Nader; Jahanbakhsh, H.; Jahangiri, Behnam

    2017-08-01

    Asphalt binder is responsible for the thermo-viscoelastic mechanical behavior of asphalt concrete. Upon application of pure compressive stress to an asphalt concrete specimen, the stress is transferred by mechanisms such as aggregate interlock and the adhesion/cohesion properties of asphalt mastic. In the pure tensile stress mode, aggregate interlock plays a limited role in stress transfer, and the mastic phase plays the dominant role through its adhesive/cohesive and viscoelastic properties. Under actual combined loading patterns, any coordinate direction may experience different stress modes; therefore, the mechanical behavior is not the same in the different directions and the asphalt specimen behaves as an anisotropic material. The present study developed an anisotropic nonlinear viscoelastic constitutive relationship that is sensitive to the tension/compression stress mode by extending Schapery's nonlinear viscoelastic model. The proposed constitutive relationship was implemented in Abaqus using a user material (UMAT) subroutine in an implicit scheme. Uniaxial compression and indirect tension (IDT) testing were used to characterize the viscoelastic properties of the bituminous materials and to calibrate and validate the proposed constitutive relationship. Compressive and tensile creep compliances were calculated using uniaxial compression, as well as IDT test results, for different creep-recovery loading patterns at intermediate temperature. The results showed that both tensile creep compliance and its rate were greater than those of compression. The calculated deflections based on these IDT test simulations were compared with experimental measurements and were deemed acceptable. This suggests that the proposed viscoelastic constitutive relationship correctly demonstrates the viscoelastic response and is more accurate for analysis of asphalt concrete in the laboratory or in situ.

  14. Attenuation of oxidative stress and cardioprotective effects of zinc supplementation in experimental diabetic rats.

    Science.gov (United States)

    Barman, Susmita; Srinivasan, Krishnapura

    2017-02-01

    Oxidative stress plays a major role in the pathogenesis of diabetes mellitus, which further exacerbates damage of cardiac, hepatic and other tissues. We have recently reported that Zn supplementation beneficially modulates hyperglycaemia and hypoinsulinaemia, with attendant reduction of associated metabolic abnormalities in diabetic rats. The present study assessed the potential of Zn supplementation in modulating oxidative stress and cardioprotective effects in diabetic rats. Diabetes was induced in Wistar rats with streptozotocin, and groups of diabetic rats were treated with 5- and 10-fold dietary Zn interventions (0·19 and 0·38 g Zn/kg diet) for 6 weeks. The markers of oxidative stress, antioxidant enzyme activities and concentrations of antioxidant molecules, lipid profile, and expressions of fibrosis and pro-apoptotic factors in the cardiac tissue were particularly assessed. Supplemental Zn showed significant attenuation of diabetes-induced oxidative stress in terms of altered antioxidant enzyme activities and increased the concentrations of antioxidant molecules. Hypercholesterolaemia and hyperlipidaemia were also significantly countered by Zn supplementation. Along with attenuated oxidative stress, Zn supplementation also showed significant cardioprotective effects by altering the mRNA expressions of fibrosis and pro-apoptotic factors (by >50 %). The expression of lipid oxidative marker 4-hydroxy-2-nonenal (4-HNE) protein in cardiac tissue of diabetic animals was rectified (68 %) by Zn supplementation. Elevated cardiac and hepatic markers in circulation and pathological abnormalities in cardiac and hepatic tissue architecture of diabetic animals were ameliorated by dietary Zn intervention. The present study indicates that Zn supplementation can attenuate diabetes-induced oxidative stress in circulation as well as in cardiac and hepatic tissues.

  15. Physiological and proteomics analyses reveal the mechanism of Eichhornia crassipes tolerance to high-concentration cadmium stress compared with Pistia stratiotes.

    Science.gov (United States)

    Li, Xiong; Zhou, Yanli; Yang, Yunqiang; Yang, Shihai; Sun, Xudong; Yang, Yongping

    2015-01-01

    Cadmium (Cd) pollution is an environmental problem worldwide. Phytoremediation is a convenient method of removing Cd from both soil and water, but its efficiency is still low, especially in aquatic environments. Scientists have been trying to improve the ability of plants to absorb and accumulate Cd based on interactions between plants and Cd, especially the mechanism by which plants resist Cd. Eichhornia crassipes and Pistia stratiotes are aquatic plants commonly used in the phytoremediation of heavy metals. In the present study, we conducted physiological and biochemical analyses to compare the resistance of these two species to Cd stress at 100 mg/L. E. crassipes showed stronger resistance and was therefore used for subsequent comparative proteomics to explore the potential mechanism of E. crassipes tolerance to Cd stress at the protein level. The expression patterns of proteins in different functional categories revealed that the physiological activities and metabolic processes of E. crassipes were affected by exposure to Cd stress. However, when some proteins related to these processes were negatively inhibited, some analogous proteins were induced to compensate for the corresponding functions. As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes. Many stress-resistance substances and proteins, such as proline and heat shock proteins (HSPs) and post translational modifications, were found to be involved in the protection and repair of functional proteins. In addition, antioxidant enzymes played important roles in ROS detoxification. These findings will facilitate further understanding of the potential mechanism of plant response to Cd stress at the protein level.

  16. Physiological and proteomics analyses reveal the mechanism of Eichhornia crassipes tolerance to high-concentration cadmium stress compared with Pistia stratiotes.

    Directory of Open Access Journals (Sweden)

    Xiong Li

    Full Text Available Cadmium (Cd pollution is an environmental problem worldwide. Phytoremediation is a convenient method of removing Cd from both soil and water, but its efficiency is still low, especially in aquatic environments. Scientists have been trying to improve the ability of plants to absorb and accumulate Cd based on interactions between plants and Cd, especially the mechanism by which plants resist Cd. Eichhornia crassipes and Pistia stratiotes are aquatic plants commonly used in the phytoremediation of heavy metals. In the present study, we conducted physiological and biochemical analyses to compare the resistance of these two species to Cd stress at 100 mg/L. E. crassipes showed stronger resistance and was therefore used for subsequent comparative proteomics to explore the potential mechanism of E. crassipes tolerance to Cd stress at the protein level. The expression patterns of proteins in different functional categories revealed that the physiological activities and metabolic processes of E. crassipes were affected by exposure to Cd stress. However, when some proteins related to these processes were negatively inhibited, some analogous proteins were induced to compensate for the corresponding functions. As a result, E. crassipes could maintain more stable physiological parameters than P. stratiotes. Many stress-resistance substances and proteins, such as proline and heat shock proteins (HSPs and post translational modifications, were found to be involved in the protection and repair of functional proteins. In addition, antioxidant enzymes played important roles in ROS detoxification. These findings will facilitate further understanding of the potential mechanism of plant response to Cd stress at the protein level.

  17. Effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.

    Science.gov (United States)

    Crino, Ondi L; Johnson, Erin E; Blickley, Jessica L; Patricelli, Gail L; Breuner, Creagh W

    2013-06-01

    Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species.

  18. Tomato transcriptome and mutant analyses suggest a role for plant stress hormones in the interaction between fruit and Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Barbara eBlanco-Ulate

    2013-05-01

    Full Text Available Fruit-pathogen interactions are a valuable biological system to study the role of plant development in the transition from resistance to susceptibility. In general, unripe fruit are resistant to pathogen infection but become increasingly more susceptible as they ripen. During ripening, fruit undergo significant physiological and biochemical changes that are coordinated by complex regulatory and hormonal signaling networks. The interplay between multiple plant stress hormones in the interaction between plant vegetative tissues and microbial pathogens has been documented extensively, but the relevance of these hormones during infections of fruit is unclear. In this work, we analyzed a transcriptome study of tomato fruit infected with Botrytis cinerea in order to profile the expression of genes for the biosynthesis, modification and signal transduction of ethylene (ET, salicylic acid (SA, jasmonic acid (JA, and abscisic acid (ABA, hormones that may be not only involved in ripening, but also in fruit interactions with pathogens. The changes in relative expression of key genes during infection and assays of susceptibility of fruit with impaired synthesis or perception of these hormones were used to formulate hypotheses regarding the involvement of these regulators in the outcome of the tomato fruit-B. cinerea interaction.

  19. Environmental Association Analyses Identify Candidates for Abiotic Stress Tolerance in Glycine soja, the Wild Progenitor of Cultivated Soybeans.

    Science.gov (United States)

    Anderson, Justin E; Kono, Thomas J Y; Stupar, Robert M; Kantar, Michael B; Morrell, Peter L

    2016-04-07

    Natural populations across a species range demonstrate population structure owing to neutral processes such as localized origins of mutations and migration limitations. Selection also acts on a subset of loci, contributing to local adaptation. An understanding of the genetic basis of adaptation to local environmental conditions is a fundamental goal in basic biological research. When applied to crop wild relatives, this same research provides the opportunity to identify adaptive genetic variation that may be used to breed for crops better adapted to novel or changing environments. The present study explores an ex situ conservation collection, the USDA germplasm collection, genotyped at 32,416 SNPs to identify population structure and test for associations with bioclimatic and biophysical variables in Glycine soja, the wild progenitor of Glycine max (soybean). Candidate loci were detected that putatively contribute to adaptation to abiotic stresses. The identification of potentially adaptive variants in this ex situ collection may permit a more targeted use of germplasm collections. Copyright © 2016 Anderson et al.

  20. Transcriptome analyses of a salt-tolerant cytokinin-deficient mutant reveal differential regulation of salt stress response by cytokinin deficiency.

    Directory of Open Access Journals (Sweden)

    Rie Nishiyama

    Full Text Available Soil destruction by abiotic environmental conditions, such as high salinity, has resulted in dramatic losses of arable land, giving rise to the need of studying mechanisms of plant adaptation to salt stress aimed at creating salt-tolerant plants. Recently, it has been reported that cytokinins (CKs regulate plant environmental stress responses through two-component systems. A decrease in endogenous CK levels could enhance salt and drought stress tolerance. Here, we have investigated the global transcriptional change caused by a reduction in endogenous CK content under both normal and salt stress conditions. Ten-day-old Arabidopsis thaliana wild-type (WT and CK-deficient ipt1,3,5,7 plants were transferred to agar plates containing either 0 mM (control or 200 mM NaCl and maintained at normal growth conditions for 24 h. Our experimental design allowed us to compare transcriptome changes under four conditions: WT-200 mM vs. WT-0 mM, ipt1,3,5,7-0 mM vs. WT-0 mM, ipt1,3,5,7-200 mM vs. ipt1,3,5,7-0 mM and ipt1,3,5,7-200 mM vs. WT-200 mM NaCl. Our results indicated that the expression of more than 10% of all of the annotated Arabidopsis genes was altered by CK deficiency under either normal or salt stress conditions when compared to WT. We found that upregulated expression of many genes encoding either regulatory proteins, such as NAC, DREB and ZFHD transcription factors and the calcium sensor SOS3, or functional proteins, such as late embryogenesis-abundant proteins, xyloglucan endo-transglycosylases, glycosyltransferases, glycoside hydrolases, defensins and glyoxalase I family proteins, may contribute to improved salt tolerance of CK-deficient plants. We also demonstrated that the downregulation of photosynthesis-related genes and the upregulation of several NAC genes may cause the altered morphological phenotype of CK-deficient plants. This study highlights the impact of CK regulation on the well-known stress-responsive signaling pathways, which

  1. Hydrodynamic Study of a Hollow Fiber Membrane System Using Experimental and Numerical Derived Surface Shear Stresses

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Hunze, M.; Nopens, I.

    2012-01-01

    th percentile) and not the movement of fibers. The latter is likely due to shielding effects or fiber sway, significantly affecting shear stresses at the high end of the distribution. However, this was not accounted for in the model in this study. Despite these deviations, the CFD model in its...

  2. Experimental stress and immunological reactivity: a closer look at perceived uncontrollability

    NARCIS (Netherlands)

    Brosschot, J. F.; Godaert, G. L.; Benschop, R. J.; Olff, M.; Ballieux, R. E.; Heijnen, C. J.

    1998-01-01

    Although stressor uncontrollability has been shown to suppress immune responses in animals and for human subjects, the results have been inconsistent. We reanalyzed results of our previous study regarding stress-related immune deviation in man, to establish whether perceived uncontrollability of an

  3. Experimental stress and immunological reactivity : A closer look at perceived uncontrollability

    NARCIS (Netherlands)

    Brosschot, JF; Godaert, GLR; Benschop, RJ; Olff, M; Ballieux, RE; Heijnen, CJ

    1998-01-01

    Objective: Although stressor uncontrollability has been shown to suppress immune responses in animals and for human subjects, the results have been inconsistent. We reanalyzed results of our previous study regarding stress-related immune deviation in man, to establish whether perceived

  4. Investigation of the Role of Stress in Inflammatory Bowel Disease Using Zebrafish as an Experimental Model

    Science.gov (United States)

    2012-08-01

    pathogenesis. For instance, while stress has for many years been implicated in symptom precipitation, the role of the normal gut flora (microbiome) has only...cloning and expression of two melanin-concentrating hormone receptors in goldfish. Peptides 30:1990-6. 13. Kokkotou, E., Moss , A. C., Torres, D

  5. Experimental application of contour method for determination of residual stress in subsurface layers of milled sample

    Directory of Open Access Journals (Sweden)

    Karel Horák

    2012-01-01

    Full Text Available Determination of residual stress close to the sample surface is in the most cases performed by hole-drilling method, X-Ray diffraction or neutron diffraction. Each of these methods has its benefits and disadvantages. In case of diffraction methods the measurement speed is the main disadvantage. It is also very problematic to apply diffraction method in case of sample with mechanically deformed surface, for example by standard machining operations. Therefore, determined results are very often confusing and hard to interpret. On the other side, hole drilling method is less sensitive to quality of sample surface than diffraction methods, but measurement realization is quite expensive and equipment demanding (strain gage rosettes, miniature milling cutter, high speed milling machine, pc equipment,….Recently introduce contour method used for determination of residual stress inside the sample is very fast, can be performed with almost common laboratory equipment and combines traditional stance with modern numerical methods by FEM. Contour method was selected for determination of residual stress below the milled surface and the dependency of milling process quality on residual stress value is demonstrated.

  6. Numerical and Experimental Determination of Strain (Stress) Concentration Factors of Welded Joints between Square Hollow Sections

    NARCIS (Netherlands)

    Puthli, R.S.; Wardenier, J.; De Koning, C.H.M.; Van Wingerde, A.M.; Van Dooren, F.J.

    1988-01-01

    This article presents methods of approach for finite element modelling of joints made of rectangular hollow steel sections where the brace members are welded to the face of the chord, to obtain strain (stress) concentration factors, SNCF (SCF). X, T and K type joints are considered. Simple modelling

  7. Endocrinological and behavioural adaptations to experimentally induced physical stress in horses

    NARCIS (Netherlands)

    Graaf-Roelfsema, E. de

    2007-01-01

    The major objective of this thesis is to find parameters to diagnose early overtraining (a stress-related disorder) in horses. Diagnosing overtraining remains still a major challenge. In man, a decrease in performance despite normal training, is indicative for the syndrome. The diagnosis is made by

  8. Oxidative Stress in Training, Overtraining and Detraining: from Experimental to Applied Research

    Directory of Open Access Journals (Sweden)

    Ruzicic Radica Dragojlovic

    2016-12-01

    Full Text Available According to the hormesis theory, the responses of biological systems to stressors in exercise training may be explained by a U-shaped curve with inactivity and overtraining as the two endpoints. Both of these endpoints decrease physiological functions. Markers of oxidative stress may be important parameters for biological monitoring of athletes. Numerous studies have shown that acute exercise has the potential to induce oxidative stress, but regular exposure to an increased level of prooxidants leads to upregulation of the endogenous antioxidative defence system (ADS of an athlete. Studies that explored the redox state in athletes during the competitive season showed that the antioxidative status changes depending on the training load and training phase. During the training season, a state of fatigue known as overtraining may occur, which results from an excessive training load. Oxidative stress has been suggested as one of the causes of overtraining syndrome. Based on the existing studies, it can be said that a connection exists, but whether oxidative stress is a cause or a consequence of overtraining is yet to be clarified. Furthermore, detraining (training reduction or cessation leads to a partial or complete loss of training-induced anatomical, physiological and performance adaptations; therefore, it seems reasonable to assume that changes in ADS are also reversible.

  9. Emotions and eating. Self-reported and experimentally induced changes in food intake under stress.

    Science.gov (United States)

    Wallis, D J; Hetherington, M M

    2009-04-01

    Two studies investigated the stress-eating relationship. The first examined self-reported changes in intake of snack foods, whilst the second investigated stress-induced overconsumption in a laboratory setting comparing high (HF) and low-fat (LF) snacks. Eighty-nine females completed the Dutch Eating Behaviour Questionnaire (DEBQ) [Van Strien, T., Fritjers, J. E. R., Bergers, G. P. A., & Defares, P. B. (1986). Dutch Eating Behaviour Questionnaire for assessment of restrained, emotional and external eating behaviour. International Journal of Eating Disorders, 5, 295-315] and a self-report measure designed to evaluate changes in eating in response to stress. Increased intake of HF snacks was associated with high emotional eating but not with restraint. A laboratory-based experiment compared intake of HF and LF snacks after ego-threatening and neutral Stroop colour-naming tasks. Intake was suppressed by 31.8% in restrained compared to unrestrained eaters across tasks. Restrained eaters consumed significantly less after ego-threat than after the neutral manipulation, but this was associated only with intake of the LF snack. Restrained eaters' intake of dried fruit was suppressed by 33.2% after ego-threat relative to the neutral task, despite a significant increase in hunger for this group following ego-threat. These results suggest that the type and variety of foods offered influences the link between stress and eating in laboratory settings. Further research should aim to replicate and extend these findings, with a view to informing potential interventions for stress-related eating.

  10. Genome-Wide Characterization of Heat-Shock Protein 70s from Chenopodium quinoa and Expression Analyses of Cqhsp70s in Response to Drought Stress.

    Science.gov (United States)

    Liu, Jianxia; Wang, Runmei; Liu, Wenying; Zhang, Hongli; Guo, Yaodong; Wen, Riyu

    2018-01-23

    Heat-shock proteins (HSPs) are ubiquitous proteins with important roles in response to biotic and abiotic stress. The 70-kDa heat-shock genes (Hsp70s) encode a group of conserved chaperone proteins that play central roles in cellular networks of molecular chaperones and folding catalysts across all the studied organisms including bacteria, plants and animals. Several Hsp70s involved in drought tolerance have been well characterized in various plants, whereas no research on Chenopodium quinoa HSPs has been completed. Here, we analyzed the genome of C. quinoa and identified sixteen Hsp70 members in quinoa genome. Phylogenetic analysis revealed the independent origination of those Hsp70 members, with eight paralogous pairs comprising the Hsp70 family in quinoa. While the gene structure and motif analysis showed high conservation of those paralogous pairs, the synteny analysis of those paralogous pairs provided evidence for expansion coming from the polyploidy event. With several subcellular localization signals detected in CqHSP70 protein paralogous pairs, some of the paralogous proteins lost the localization information, indicating the diversity of both subcellular localizations and potential functionalities of those HSP70s. Further gene expression analyses revealed by quantitative polymerase chain reaction (qPCR) analysis illustrated the significant variations of Cqhsp70s in response to drought stress. In conclusion, the sixteen Cqhsp70s undergo lineage-specific expansions and might play important and varied roles in response to drought stress.

  11. Experimental evaluation of the pure configurational stress assumption in the flow dynamics of entangled polymer melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Bejenariu, Anca Gabriela; Hassager, Ole

    2010-01-01

    A filament stretching rheometer was used for measuring the startup of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational strain rate. A narrow molecular mass distribution linear polyisoprene with a molecular weight of 483 kg/mole was subjected...... to the flow in the non-linear flow regime. This has allowed highly elastic measurements within the limit of pure orientational stress, as the time of the flow was considerably smaller than the Rouse time. A Doi-Edwards [J. Chem. Soc., Faraday Trans. 2 74, 1818-1832 (1978)] type of constitutive model...... with the assumption of pure configurational stress was accurately able to predict the startup as well as the reversed flow behavior. This confirms that this commonly used theoretical picture for the flow of polymeric liquids is a correct physical principle to apply. c 2010 The Society of Rheology. [DOI: 10.1122/1.3496378]...

  12. [The application of low-intensity electromagnetic radiation under immobilization stress conditions (an experimental study)].

    Science.gov (United States)

    Korolev, Iu N; Bobrovnitskiĭ, I P; Nikoulina, L A; Mikhaĭlik, L V; Geniatulina, M S; Bobkova, A S

    2014-01-01

    The experiments carried out on outbred male white rats with the use of optical, electron-microscopic, biochemical, and radioimmunological methods have demonstrated that the application of low-intensity electromagnetic radiation (LI-EMR) with a flow density of 1 mcW/cm2 and a frequency of around 1,000 MHz both in the primary prophylaxis regime and as the therapeuticpreventive modality arrested the development of post-stress disorders in the rat testicles, liver, and thymus; moreover, it promoted activation of the adaptive, preventive, and compensatory processes. The data obtained provide a rationale for the application of low-intensity electromagnetic radiation to protect the organism from negative effects of stressful factors.

  13. Liver mitochondrial dysfunction and oxidative stress in the pathogenesis of experimental nonalcoholic fatty liver disease

    Directory of Open Access Journals (Sweden)

    Oliveira C.P.M.S.

    2006-01-01

    Full Text Available Oxidative stress and hepatic mitochondria play a role in the pathogenesis of nonalcoholic fatty liver disease. The aim of the present study was to evaluate the role of hepatic mitochondrial dysfunction and oxidative stress in the pathogenesis of the disease. Fatty liver was induced in Wistar rats with a choline-deficient diet (CD; N = 7 or a high-fat diet enriched with PUFAs-omega-3 (H; N = 7 for 4 weeks. The control group (N = 7 was fed a standard diet. Liver mitochondrial oxidation and phosphorylation were measured polarographically and oxidative stress was estimated on the basis of malondialdehyde and glutathione concentrations. Moderate macrovacuolar liver steatosis was observed in the CD group and mild liver steatosis was observed in the periportal area in the H group. There was an increase in the oxygen consumption rate by liver mitochondria in respiratory state 4 (S4 and a decrease in respiratory control rate (RCR in the CD group (S4: 32.70 ± 3.35; RCR: 2.55 ± 0.15 ng atoms of O2 min-1 mg protein-1 when compared to the H and control groups (S4: 23.09 ± 1.53, 17.04 ± 2.03, RCR: 3.15 ± 0.15, 3.68 ± 0.15 ng atoms of O2 min-1 mg protein-1, respectively, P < 0.05. Hepatic lipoperoxide concentrations were significantly increased and the concentration of reduced glutathione was significantly reduced in the CD group. A choline-deficient diet causes moderate steatosis with disruption of liver mitochondrial function and increased oxidative stress. These data suggest that lipid peroxidation products can impair the flow of electrons along the respiratory chain, causing overreduction of respiratory chain components and enhanced mitochondrial reactive oxygen species. These findings are important in the pathogenesis of nonalcoholic fatty liver disease.

  14. Design and Experimental Evaluation of a 3rd Generation Addressable CMOS Piezoresistive Stress Sensing Test Chip

    Energy Technology Data Exchange (ETDEWEB)

    Sweet, J.N.; Peterson, D.W.; Hsia, A.H.

    1999-04-13

    Piezoresistive stress sensing chips have been used extensively for measurement of assembly related die surface stresses. Although many experiments can be performed with resistive structures which are directly bonded, for extensive stress mapping it is necessary to have a large number of sensor cells which can be addressed using CMOS logic circuitry. Our previous test chip, the ATC04, has 100 cells, each approximately 0.012 in. on a side, on a chip with a side dimension of 0.45 in. When a cell resistor is addressed, it is connected to a four terminal measurement bus through CMOS transmission gates. In theory, the gate resistances do not affect the measurement. In practice, there may be subtle effects which appear when very high accuracy is required. At high temperatures, gate leakage can increase to a point at which the resistor measurement becomes inaccurate. For ATC04 this occurred at or above 50 C. Here, we report on the first measurements obtained with a new prototype test chip, the ATC06. This prototype was fabricated in a 0.5 micron feature size silicided CMOS process using the MOSIS prototyping facility. The cell size was approximately 0.004 in. on a side. In order to achieve piezoresistive behavior for the implanted resistors it was necessary to employ a non-standard silicide ''blocking'' process. The stress sensitivity of both implanted and polysilicon blocked resistors is discussed. Using a new design strategy for the CMOS logic, it was possible to achieve a design in which only 5 signals had to be routed to a cell for addressing vs. 9 for ATC04. With our new design, the resistor under test is more effectively electrically isolated from other resistors on the chip, thereby improving high temperature performance. We present data showing operation up to 140 C.

  15. Stress transfer from pile group in saturated and unsaturated soil using theoretical and experimental approaches

    Directory of Open Access Journals (Sweden)

    al-Omari Raid R.

    2017-01-01

    Full Text Available Piles are often used in groups, and the behavior of pile groups under the applied loads is generally different from that of single pile due to the interaction of neighboring piles, therefore, one of the main objectives of this paper is to investigate the influence of pile group (bearing capacity, load transfer sharing for pile shaft and tip in comparison to that of single piles. Determination of the influence of load transfer from the pile group to the surrounding soil and the mechanism of this transfer with increasing the load increment on the tip and pile shaft for the soil in saturated and unsaturated state (when there is a negative pore water pressure. Different basic properties are used that is (S = 90%, γd = 15 kN / m3, S = 90%, γd = 17 kN / m3 and S = 60%, γd =15 kN / m3. Seven model piles were tested, these was: single pile (compression and pull out test, 2×1, 3×1, 2×2, 3×2 and 3×3 group. The stress was measured with 5 cm diameter soil pressure transducer positioned at a depth of 5 cm below the pile tip for all pile groups. The measured stresses below the pile tip using a soil pressure transducer positioned at a depth of 0.25L (where L is the pile length below the pile tip are compared with those calculated using theoretical and conventional approaches. These methods are: the conventional 2V:1H method and the method used the theory of elasticity. The results showed that the method of measuring the soil stresses with soil pressure transducer adopted in this study, gives in general, good results of stress transfer compared with the results obtained from the theoretical and conventional approaches.

  16. Darbepoetin alpha reduces oxidative stress and chronic inflammation in atherosclerotic lesions of apo E deficient mice in experimental renal failure.

    Directory of Open Access Journals (Sweden)

    Nicole Arend

    Full Text Available BACKGROUND: Cardiovascular morbidity and mortality is very important in patients with chronic renal failure. This occurs even in mild impairment of renal function and may be related to oxidative stress and chronic inflammation. The nephrectomized apo E knockout mouse is an accepted model for evaluating atherosclerosis in renal dysfunction. Erythropoietin derivates showed anti-oxidative and anti-inflammatory effects. Therefore, this study evaluates the effects of Darbepoetin on markers of oxidative stress and chronic inflammation in atherosclerotic lesions in apo E knockout mice with renal dysfunction. METHODS: Apo E knockout mice underwent unilateral (Unx, n = 20 or subtotal (Snx, n = 26 nephrectomy or sham operation (Sham, n = 16. Mice of each group were either treated with Darbepoetin or saline solution, a part of Snx mice received a tenfold higher dose of Darbepoetin. The aortic plaques were measured and morphologically characterized. Additional immunhistochemical analyses were performed on tissue samples taken from the heart and the aorta. RESULTS: Both Unx and Snx mice showed increased expression of markers of oxidative stress and chronic inflammation. While aortic plaque size was not different, Snx mice showed advanced plaque stages when compared to Unx mice. Darbepoetin treatment elevated hematocrit and lowered Nitrotyrosin as one marker of oxidative stress, inflammation in heart and aorta, plaque stage and in the high dose even plaque cholesterol content. In contrast, there was no influence of Darbepoetin on aortic plaque size; high dose Darbepoetin treatment resulted in elevated renal serum parameters. CONCLUSION: Darbepoetin showed some protective cardiovascular effects irrespective of renal function, i.e. it improved plaque structure and reduced some signs of oxidative stress and chronic inflammation without affecting plaque size. Nevertheless, the dose dependent adverse effects must be considered as high Darbepoetin treatment

  17. Emotion, stress, and cardiovascular response: an experimental test of models of positive and negative affect.

    Science.gov (United States)

    Dowd, Haulie; Zautra, Alex; Hogan, Michael

    2010-09-01

    The nature of the relationship between positive affect (PA) and negative affect (NA) has been a topic of debate for some time. In particular, there are gaps in our knowledge of the independent effects of PA and NA on health under stress. The study examined the effects of a laboratory-induced stressor on the experience of PA and NA, and the effects of affect on cardiovascular (CV) reactivity and recovery. A sample of 56 female college students was randomly assigned to a public speaking (stress) task or a silent reading (control) task. Pre- and posttask PA and NA were measured using the Positive and Negative Affect Schedule (PANAS Watson J Pers Soc Psychol 54:1,063-1,070, 1988). Baseline, task, and posttask cardiovascular measures were also recorded. The results indicated that PA and NA responded differently to the stressor and contributed independently to the prediction of both CV reactivity and recovery. Of particular interest was the finding that higher levels of both PA and NA predicted greater CV recovery. Results are discussed in light of the debate concerning the (in)dependence of positive and negative emotions and the importance of understanding the dynamics of emotions, stress, and health.

  18. Theoretical and Experimental Investigation of Characteristics of Single Fracture Stress-Seepage Coupling considering Microroughness

    Directory of Open Access Journals (Sweden)

    Shengtong Di

    2017-01-01

    Full Text Available Based on the results of the test among the joint roughness coefficient (JRC of rock fracture, mechanical aperture, and hydraulic aperture proposed by Barton, this paper deduces and proposes a permeability coefficient formula of single fracture stress-seepage coupling considering microroughness by the introduction of effect variables considering the microparticle size and structural morphology of facture surface. Quasi-sandstone fracture of different particle size is made by the laboratory test, and the respective modification is made on the coupled shear-seepage test system of JAW-600 rock. Under this condition, the laboratory test of stress-seepage coupling of fracture of different particle size is carried out. The test results show that, for the different particle-sized fracture surface of the same JRC, the permeability coefficient is different, which means the smaller particle size, the smaller permeability coefficient, and the larger particle size, the larger permeability coefficient; with the increase of cranny hydraulic pressure, the permeability coefficient increases exponentially, and under the same cranny hydraulic pressure, there is relation of power function between the permeability coefficient and normal stress. Meanwhile, according to the theoretical formula, the microroughness coefficient of the fractures with different particle size is obtained by the calculation, and its accuracy and validity are verified by experiments. The theoretical verification values are in good agreement with the measured values.

  19. Survival and virulence of copper- and chlorine-stressed Yersinia enterocolitica in Experimentally infected mice

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; McFeters, G.A.

    1987-08-01

    The effect of gastric pH on the viability and virulence of Yersinia enterocolitica 0:8 after exposure to sublethal concentrations of copper and chlorine was determined in mice. Viability and injury were assessed with a nonselective TLY agar and two selective media, TLYD agar and CIN agar. Both copper and chlorine caused injury which was manifested by the inability of the cells to grow on selective media. CIN agar was more restrictive to the growth of injured cells than TLYD agar. Injury of the exposed cells was further enhanced in the gastric environment of mice. Besides injury, the low gastric pH caused extensive loss of viability in copper-exposed cells. Lethality in the chlorine-exposed cells was less extensive, and a portion of the inoculum reached the small intestine 5 min postinoculation. No adverse effect on the injured cells was apparent in the small intestine, and a substantial revival of the injury occurred in 3 to 4 h after intraluminal inoculation. The virulence of chlorine-stressed Y. enterocolitica in orally inoculated mice was similar to that of the control culture, but copper-stressed cells showed reduced virulence. Virulence was partly restored by oral administration of sodium bicarbonate before the inoculation of copper-exposed cells. Neutralization of gastric acidity had no effect on the virulence of the control of chlorine-stressed cells.

  20. Biochemical and histochemical analyses revealing endophytic Alcaligenes faecalis mediated suppression of oxidative stress in Abelmoschus esculentus challenged with Sclerotium rolfsii.

    Science.gov (United States)

    Ray, Shatrupa; Singh, Vivek; Singh, Surendra; Sarma, Birinchi Kumar; Singh, Harikesh Bahadur

    2016-12-01

    Sclerotium rolfsii is a highly aggressive pathogen that causes huge economic losses, especially in temperate climates. Alcaligenes faecalis, particularly in endophytic form, has rarely been used to control this fungus. In this study, endophytic Alcaligenes sp. strain BHU 12, BHU 16 (isolated from Abelmoschus esculentus leaf) and BHU M7 (isolated from Andrographis paniculata leaf) were reported to trigger a wide range of host defenses in Okra plant against the collar-rot pathogen S. rolfsii. Endophytic colonization of the strains in ten days old plants was assessed through re-isolation of the rif-tagged strains on rifampicin augmented nutrient agar media. The ability of the endophytic strains to induce systemic defense responses in above-ground organs was assessed by collecting leaf tissues of the Okra plants grown under non-gnotobiotic conditions at different time intervals post seedling bacterization with the endophytic biocontrol agents. The pathogen challenged unprimed plants exhibited flaccidity of the stem and leaves at 48 h post infection (hpi) in contrast to the bioprimed and challenged plants. Biochemical and histochemical analyses explained the above phenomenon as activation of phyto-peroxidases leading to an increased metabolism of the reactive oxygen species (ROS), accompanied by activation of the phenylpropanoid network and a subsequent enhancement in plant phenolics. Interestingly, though the maximum increase in the defense pathways was observed in treatments with native endophytes of Okra plant, yet the enhancement in antioxidant pathway due to A. paniculata borne endophytes was also quite significant. Thus, this work clearly demonstrates how Okra plants respond to the "non-hostile" colonization of bacterial endophytes and how induced defense response can contribute to the biocontrol activity of the endophytic strains. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Evaluation of experimental design and computational parameter choices affecting analyses of ChIP-seq and RNA-seq data in undomesticated poplar trees

    Science.gov (United States)

    2014-01-01

    Background One of the great advantages of next generation sequencing is the ability to generate large genomic datasets for virtually all species, including non-model organisms. It should be possible, in turn, to apply advanced computational approaches to these datasets to develop models of biological processes. In a practical sense, working with non-model organisms presents unique challenges. In this paper we discuss some of these challenges for ChIP-seq and RNA-seq experiments using the undomesticated tree species of the genus Populus. Results We describe specific challenges associated with experimental design in Populus, including selection of optimal genotypes for different technical approaches and development of antibodies against Populus transcription factors. Execution of the experimental design included the generation and analysis of Chromatin immunoprecipitation-sequencing (ChIP-seq) data for RNA polymerase II and transcription factors involved in wood formation. We discuss criteria for analyzing the resulting datasets, determination of appropriate control sequencing libraries, evaluation of sequencing coverage needs, and optimization of parameters. We also describe the evaluation of ChIP-seq data from Populus, and discuss the comparison between ChIP-seq and RNA-seq data and biological interpretations of these comparisons. Conclusions These and other "lessons learned" highlight the challenges but also the potential insights to be gained from extending next generation sequencing-supported network analyses to undomesticated non-model species. PMID:25081589

  2. Medical ozone therapy reduces oxidative stress and testicular damage in an experimental model of testicular torsion in rats.

    Science.gov (United States)

    Tusat, Mustafa; Mentese, Ahmet; Demir, Selim; Alver, Ahmet; Imamoglu, Mustafa

    2017-06-14

    Testicular torsion (TT) refers to rotation of the testis and twisting of the spermatic cord. TT results in ischemia-reperfusion (I/R) injury involving increased oxidative stress, inflammation and apoptosis, and can even lead to infertility. The aim of this study was to investigate the effect of ozone therapy on testicular damage due to I/R injury in an experimental torsion model. 24 male Sprague-Dawley rats were divided into 3 groups; sham-operated, torsion/detorsion (T/D), and T/D+ozone. Ozone (1mg/kg) was injected intraperi-toneally 120 minutes before detorsion and for the following 24h. Blood and tissue samples were collected at the end of 24h. Johnsen score, ischemia modified albumin (IMA), total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) levels were determined. Levels of IMA, TOS, OSI, and histopathological scores increased in the serum/tissue of the rats in the experimental T/D group. Serum IMA, TOS, and OSI levels and tissue histo-pathological scores were lower in the rats treated with ozone compared with the T/D group. Our study results suggest that ozone therapy may exhibit beneficial effects on both biochemical and histopathological findings. Clinical trials are now necessary to confirm this. Copyright® by the International Brazilian Journal of Urology.

  3. Chemopreventive effect of methanolic extract of Azadirachta indica on experimental Trypanosoma brucei induced oxidative stress in dogs.

    Science.gov (United States)

    Omobowale, Temidayo O; Oyagbemi, Ademola A; Oyewunmi, Oyefunbi A; Adejumobi, Olumuyiwa A

    2015-01-01

    The medicinal properties of Azadirachta indica have been harnessed for many years in the treatment of many diseases in both humans and animals. Twenty-five apparently healthy dogs weighing between 3 and 8 kg were randomly divided into five groups with five dogs in each group. Ameliorative effect of A. indica on erythrocyte antioxidant status and markers of oxidative stress were assessed. Liver and kidney function tests were also performed. Pre-treatment with methanolic extract of Azadirachta indica (MEAI) at different doses did not significantly alter the values of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activity in Trypanosoma brucei infection. Although, serum creatinine significantly (P indica, after 2 weeks of T. brucei infection. However, the reduced glutathione (GSH) content of the erythrocyte increased significantly in animals pre-treated with 50 mg/kg and 200 mg/kg of A. indica respectively. Markers of oxidative stress such as malondialdehyde and hydrogen peroxide generated were higher in animals infected with T. brucei with no significant (P >0.05) difference compared to the values obtained in pre-treated animals. Pre-treatment with 100 mg/kg and 200 mg/kg of A. indica significantly (P < 0.05) decreased serum myeloperoxidase activity at 2 weeks post-infection with T. brucei. From this study, MEAI showed significant ability to attenuate oxidative stress and inflammation during experimental T. brucei infection.

  4. Design, rationale and feasibility of a multidimensional experimental protocol to study early life stress

    Directory of Open Access Journals (Sweden)

    M. Dillwyn Bartholomeusz

    2017-09-01

    Full Text Available There is a rapidly accumulating body of evidence regarding the influential role of early life stress (ELS upon medical and psychiatric conditions. While self-report instruments, with their intrinsic limitations of recall, remain the primary means of detecting ELS in humans, biological measures are generally limited to a single biological system. This paper describes the design, rationale and feasibility of a study to simultaneously measure neuroendocrine, immune and autonomic nervous system (ANS responses to psychological and physiological stressors in relation to ELS. Five healthy university students were recruited by advertisement. Exclusion criteria included chronic medical conditions, psychotic disorders, needle phobia, inability to tolerate pain, and those using anti-inflammatory medications. They were clinically interviewed and physiological recordings made over a two-hour period pre, during and post two acute stressors: the cold pressor test and recalling a distressing memory. The Childhood Trauma Questionnaire and the Parental Bonding Index were utilised to measure ELS. Other psychological measures of mood and personality were also administered. Measurements of heart rate, blood pressure, respiratory rate, skin conductance, skin blood flow and temporal plasma samples were successfully obtained before, during and after acute stress. Participants reported the extensive psychological and multisystem physiological data collection and stress provocations were tolerable. Most (4/5 participants indicated a willingness to return to repeat the protocol, indicating acceptability. Our protocol is viable and safe in young physically healthy adults and allows us to assess simultaneously neuroendocrine, immune and autonomic nervous system responses to stressors in persons assessed for ELS.

  5. 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

  6. IMPROVEMENT IN OXIDATIVE STRESS AFTER DUODENOJEJUNOSTOMY IN AN EXPERIMENTAL MODEL OF TYPE 2 DIABETES MELLITUS.

    Science.gov (United States)

    Wietzycoski, Cacio Ricardo; Marchesini, João Caetano Dallegrave; Al-Themyat, Sultan; Meyer, Fabiola Shons; Trindade, Manoel Roberto Maciel

    Type 2 Diabetes Mellitus is a multifactorial syndrome with severe complications. Oxidative stress is accepted as a causal factor of chronic complications. To demonstrate alterations in oxidative stress after metabolic surgery. Twenty-four 2-day-old Wistar rats were used. In 16, Type 2 Diabetes Mellitus was induced by 100 mg/kg streptozotocin injection. The development of diabetes was confirmed after 10 weeks using an oral glucose tolerance test. Eight diabetic rats composed the diabetic surgical group; the remaining eight composed the diabetic group. Eight animals in which diabetes was not induced formed the clinical control group. The Marchesini technique was used in the diabetic surgical group. After 90 days, the rats were sacrificed, and the oxidative stress markers were measured. Thiobarbituric acid reactive substances, superoxide dismutase and catalase were significantly reduced in the diabetic surgical group compared to the diabetic group. The duodenojejunostomy was effective in controlling the exacerbated oxidative stress present in diabetic rats. Diabete melito tipo 2 é síndrome multifatorial com complicações graves. O estresse oxidativo é aceito como um fator causal de complicações crônicas. Demonstrar alterações no estresse oxidativo após a cirurgia metabólica. Foram utilizados 24 ratos Wistar de dois dias de idade. Em 16, diabete melito tipo 2 foi induzida por 100 mg/kg de injeção de estreptozotocina. O desenvolvimento do diabete foi confirmado após 10 semanas, utilizando teste oral de tolerância à glucose. Oito ratos diabéticos compuseram o grupo cirúrgico diabético; os oito restantes constituíram o grupo diabético. Oito animais em que não foi induzido o diabete formaram o grupo controle clínico. A técnica de Marchesini foi utilizada no grupo cirúrgico diabético. Após 90 dias, os ratos foram sacrificados, e os marcadores de estresse oxidativo foram medidos. Ácido tiobarbitúrico, superóxido dismutase e catalase foram

  7. Eclogite-facies metamorphic reactions under stress and faulting in granulites from the Bergen Arcs, Norway: an experimental investigation

    Science.gov (United States)

    Incel, Sarah; Hilairet, Nadège; Labrousse, Loïc; Andersen, Torgeir B.; Wang, Yanbin; Schubnel, Alexandre

    2017-04-01

    Field observations from the Bergen Arcs, Norway, demonstrate a network of pseudotachylites quenched under eclogite-facies conditions in mafic granulites. In these nominally anhydrous high-pressure high-temperature (HP/HT) rocks the formation of pseudotachylites, believed to represent fossilized earthquakes, cannot be explained by processes akin to dehydration embrittlement. On the contrary, the transition to eclogite is expected to involve hydration of the initial rock. To experimentally investigate the underlying mechanisms leading to brittle failure in HP/HT rocks, we performed deformation experiments on natural granulite samples from the Bergen Arcs. The experiments were conducted under eclogite-facies conditions (2-3 GPa, 990-1220 K) to trigger the breakdown of plagioclase - the main constituent of granulite. For these experiments, both a D-DIA and a Griggs apparatus were used. The D-DIA press is mounted on a synchrotron beamline, enabling us to monitor strain, stress, and phase changes in-situ while contemporaneously recording acoustic emissions. The Griggs experiments were performed on a new device installed at ENS Paris, in which only stress-strain were recorded, and post-mortem microstructures investigated. The initial material consisted of a fine grain size granulite powder (powder plus the adhesion water on grain surfaces. Mechanical data together with XRD observations and the record of acoustic emissions demonstrate a correlation between stress drops, the growth of plagioclase breakdown products and the onset of acoustic emissions during deformation of our specimen within the eclogitic field. Microstructural analysis show remarkable similarities with that of the natural ecoligitic pseudotachylites of the Bergen arcs. The plagioclase decomposition products form narrow conjugated shear bands, along which dissected and displaced crystals are found in the samples. The lack of microstructural evidence for macroscopic brittle failure in our microstructures

  8. Geraniol attenuates oxidative stress by Nrf2 activation in diet-induced experimental atherosclerosis.

    Science.gov (United States)

    Jayachandran, Muthukumaran; Chandrasekaran, Balaji; Namasivayam, Nalini

    2015-07-01

    Preclinical and clinical studies suggest the use of antioxidants as an effective measure to reduce the progression of oxidative-stress-related disorders. Nuclear factor E2-related factor 2 (Nrf2) is a key component to cellular redox homeostasis in the attenuation of oxidative-stress-associated pathological processes. The objective of the current study was to evaluate the role of geraniol (GOH) in preserving the plasma lipid status, endothelial function, antioxidant status, and inhibition of lipid peroxidation (LPO) in hamsters fed an atherogenic diet (AD). Male Syrian hamsters were randomly grouped into four groups: group 1 was control animals; group 2 was animals fed GOH alone (100 mg/kg bw po); group 3 was animals fed AD (standard pellet diet+10% coconut oil+0.25% cholesterol+0.25% cholic acid); and group 4 was fed AD+GOH (100 mg/kg bw) for 12 weeks. At the end of the feeding period, the animals were sacrificed and the liver, heart, and aorta from each group were analyzed for antioxidants, LPO markers, and histological changes. AD feeding induced a significant change in lipid profile, endothelial function marker, activities of the antioxidant enzymes, alterations in the LPO markers, Nrf2 expression, and equally significant changes in the organ histology. Supplementation with GOH appreciably prevented the alterations induced by the AD on all the above parameters. Thus, GOH offers marked protection against AD-induced abnormalities.

  9. Genetic Adaptation to Salt Stress in Experimental Evolution of Desulfovibrio vulgaris Hildenborough

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Aifen; Hillesland, Kristina; He, Zhili; Joachimiak, Marcin; Zane, Grant; Dehal, Paramvir; Arkin, Adam; Stahl, David; Wall, Judy; Hazen, Terry; Zhou, Jizhong; Baidoo, Edward; Benke, Peter; Mukhopadhyay, Aindrila

    2010-05-17

    High salinity is one of the most common environmental stressors. In order to understand how environmental organisms adapt to salty environment, an experiment evolution with sulfate reducing bacteria Desulfovibrio vugaris Hildenborough was conducted. Control lines and salt-stressed lines (6 lines each) grown in minimal medium LS4D or LS4D + 100 mM NaCl were transferred for 1200 generations. The salt tolerance was tested with LS4D supplemented with 250 mM NaCl. Statistical analysis of the growth data suggested that all lines adapted to their evolutionary environment. In addition, the control lines performed better than the ancestor with faster growth rate, higher biomass yield and shorter lag phase under salty environment they did not evolve in. However, the salt-adapted lines performed better than the control lines on measures of growth rate and yield under salty environment, suggesting that the salt?evolved lines acquired mutations specific to having extra salt in LS4D. Growth data and gene transcription data suggested that populations tended to improve till 1000 generations and active mutations tended to be fixed at the stage of 1000 generations. Point mutations and insertion/deletions were identified in isolated colonies from salt-adapted and control lines via whole genome sequencing. Glu, Gln and Ala appears to be the major osmoprotectant in evolved salt-stressed line. Ongoing studies are now characterizing the contribution of specific mutations identified in the salt-evolved D. vulgaris.

  10. Sensory trigeminal ULF-TENS stimulation reduces HRV response to experimentally induced arithmetic stress: A randomized clinical trial.

    Science.gov (United States)

    Monaco, Annalisa; Cattaneo, Ruggero; Ortu, Eleonora; Constantinescu, Marian Vladimir; Pietropaoli, Davide

    2017-05-01

    Ultra Low Frequency Transcutaneous Electric Nervous Stimulation (ULF-TENS) is extensively used for pain relief and for the diagnosis and treatment of temporomandibular disorders (TMD). In addition to its local effects, ULF-TENS acts on the autonomic nervous system (ANS), with particular reference to the periaqueductal gray (PAG), promoting the release of endogenous opioids and modulating descending pain systems. It has been suggested that the PAG participates in the coupling between the emotional stimulus and the appropriate behavioral autonomic response. This function is successfully investigated by HRV. Therefore, our goal is to investigate the effects of trigeminal ULF-TENS stimulation on autonomic behavior in terms of HRV and respiratory parameters during an experimentally-induced arithmetic stress test in healthy subjects. Thirty healthy women between 25 and 35years of age were enrolled and randomly assigned to either the control (TENS stimulation off) or test group (TENS stimulation on). Heart (HR, LF, HF, LF/HF ratio, DET, RMSSD, PNN50, RR) and respiratory (BR) rate were evaluated under basal, T1 (TENS off/on), and stress (mathematical task) conditions. Results showed that HRV parameters and BR significantly changed during the arithmetic stress paradigm (pTENS and control group could be discriminated only by non-linear HRV data, namely RR and DET (p=0.038 and p=0.027, respectively). During the arithmetic task, LF/HF ratio was the most sensitive parameter to discriminate between groups (p=0.019). Our data suggest that trigeminal sensory ULF-TENS reduces the autonomic response in terms of HRV and BR during acute mental stress in healthy subjects. Future directions of our work aim at applying the HRV and BR analysis, with and without TENS stimulation, to individuals with dysfunctional ANS among those with TMD. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Sex Difference in Oxidative Stress Parameters in Spinal Cord of Rats with Experimental Autoimmune Encephalomyelitis: Relation to Neurological Deficit.

    Science.gov (United States)

    Dimitrijević, Mirjana; Kotur-Stevuljević, Jelena; Stojić-Vukanić, Zorica; Vujnović, Ivana; Pilipović, Ivan; Nacka-Aleksić, Mirjana; Leposavić, Gordana

    2017-02-01

    The study examined (a) whether there is sex difference in spinal cord and plasma oxidative stress profiles in Dark Agouti rats immunised for experimental autoimmune encephalomyelitis (EAE), the principal experimental model of multiple sclerosis, and (b) whether there is correlation between the oxidative stress in spinal cord and neurological deficit. Regardless of rat sex, with the disease development xanthine oxidase (XO) activity and inducible nitric oxide synthase (iNOS) mRNA expression increased in spinal cord, whereas glutathione levels decreased. This was accompanied by the rise in spinal cord malondialdehyde level. On the other hand, with EAE development superoxide dismutase (SOD) activity decreased, while O2(-) concentration increased only in spinal cord of male rats. Consequently, SOD activity was lower, whereas O2(-) concentration was higher in spinal cord of male rats with clinically manifested EAE. XO activity and iNOS mRNA expression were also elevated in their spinal cord. Consistently, in the effector phase of EAE the concentration of advanced oxidation protein product (AOPP) was higher in spinal cord of male rats, which exhibit more severe neurological deficit than their female counterparts. In as much as data obtained in the experimental models could be translated to humans, the findings may be relevant for designing sex-specific antioxidant therapeutic strategies. Furthermore, the study indicated that the increased pro-oxidant-antioxidant balance in plasma may be an early indicator of EAE development. Moreover, it showed that plasma AOPP level may indicate not only actual activity of the disease, but also serve to predict severity of its course.

  12. Experimental Analysis of Residual Stresses in Samples of Austenitic Stainless Steel Welded on Martensitic Stainless Steel Used for Kaplan Blades Repairs

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2011-01-01

    Full Text Available Residual stresses occur in materials as a result of mechanical processes: welding, machining, grinding etc. If residual stresses reach high values they can accelerate the occurrence of cracks and erosion of material. An experimental research was made in order to study the occurrence of residual stresses in the repaired areas of hydraulic turbine components damaged by cavitation erosion. An austenitic stainless steel was welded in various layer thicknesses on a martensitic stainless steel base. The residual stresses were determined using the hole drilling strain gage method.

  13. Levothyroxine replacement therapy with vitamin E supplementation prevents oxidative stress and cognitive deficit in experimental hypothyroidism.

    Science.gov (United States)

    Pan, Tianrong; Zhong, Mingkui; Zhong, Xing; Zhang, Yanqing; Zhu, Defa

    2013-04-01

    Hypothyroidism has a variety of adverse effects on cognitive function. The treatment of levothyroxine alone cannot restore cognitive defects of hypothyroid patients. Antioxidant vitamin E supplementation could be useful in disturbances which are associated with oxidative stress and could effectively slow the progression of Alzheimer disease. Thus, the purpose of this study was to evaluate oxidative stress status of the serum and hippocampus in hypothyroidism and to examine the effects of levothyroxine replacement therapy with vitamin E supplementation on cognitive deficit. Sprague-Dawley rats were randomly divided into five groups: control group, PTU group, PTU + Vit E group, PTU + L-T4 group, and PTU + L-T4 + Vit E group. Serum and hippocampus malondialdehyde (MDA) levels were determined using the thiobarbituric-acid reactive substances method. Serum and hippocampus superoxide dismutase (SOD) levels were determined by measuring its ability to inhibit the photoreduction of nitroblue tetrazolium. Learning and memory was assessed by Morris water maze test. In the present study, we found that the rats of PTU + Vit E group spent less time to find the platform on days 2, 3, 4, and 5 than the PTU group. Moreover, the rats of PTU + L-T4 + Vit E group spent less time to find the platform on days 4 and 5 than the PTU + L-T4 group. The time spent in the target quadrants was measured in the probe test and no difference was observed in all groups. Oxidative damage has been observed in the serum and hippocampus of hypothyroidism rat. SOD levels of serum and hippocampus tissue were significantly increased and MDA levels were significantly decreased in the PTU + Vit E and PTU + L-T4 + Vit E groups than the PTU and PTU + L-T4 groups. Therefore, these findings indicate that levothyroxine replacement therapy with vitamin E supplementation may ameliorate cognitive deficit in PTU-induced hypothyroidism through the decrease of oxidative stress status.

  14. Refined experimental methodology for assessing the heat dissipated in cyclically loaded materials at low stress levels

    Science.gov (United States)

    Maquin, François; Pierron, Fabrice

    2007-03-01

    The present study is aimed at studying the heat generated in steel specimens cyclically tested at stresses lower than their macroscopic elastic limit, in the objective of detecting the onset of microplasticity. First, the data processing procedure is presented to calculate heat sources and thermal energy levels from temperature maps. Then, a sensitivity study is performed to establish the smallest energy value that can be detected above noise. Finally, results are presented for a cold rolled low carbon steel material. It is shown that two main mechanisms of dissipation are present, the first one corresponding to viscoelastic effects and the second one associated to microplasticity. To cite this article: F. Maquin, F. Pierron, C. R. Mecanique 335 (2007).

  15. A preliminary experimental examination of worldview verification, perceived racism, and stress reactivity in African Americans.

    Science.gov (United States)

    Lucas, Todd; Lumley, Mark A; Flack, John M; Wegner, Rhiana; Pierce, Jennifer; Goetz, Stefan

    2016-04-01

    According to worldview verification theory, inconsistencies between lived experiences and worldviews are psychologically threatening. These inconsistencies may be key determinants of stress processes that influence cardiovascular health disparities. This preliminary examination considers how experiencing injustice can affect perceived racism and biological stress reactivity among African Americans. Guided by worldview verification theory, it was hypothesized that responses to receiving an unfair outcome would be moderated by fairness of the accompanying decision process, and that this effect would further depend on the consistency of the decision process with preexisting justice beliefs. A sample of 118 healthy African American adults completed baseline measures of justice beliefs, followed by a laboratory-based social-evaluative stressor task. Two randomized fairness manipulations were implemented during the task: participants were given either high or low levels of distributive (outcome) and procedural (decision process) justice. Glucocorticoid (cortisol) and inflammatory (C-reactive protein) biological responses were measured in oral fluids, and attributions of racism were also measured. The hypothesized 3-way interaction was generally obtained. Among African Americans with a strong belief in justice, perceived racism, cortisol, and C-reactive protein responses to low distributive justice were higher when procedural justice was low. Among African Americans with a weak belief in justice however, these responses were higher when a low level of distributive justice was coupled with high procedural justice. Biological and psychological processes that contribute to cardiovascular health disparities are affected by consistency between individual-level and contextual justice factors. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  16. The effectiveness of pelvic floor exercises, digital vaginal palpation and interpersonal support on stress urinary incontinence: an experimental study.

    Science.gov (United States)

    Tsai, Yueh-Chi; Liu, Chieh-Hsing

    2009-09-01

    The objective of this study is to examine if interpersonal support and digital vaginal palpation (DVP) as part of the pelvic floor muscle exercise (PFME) training is more effective for stress urinary incontinence (SUI) than PFME with a printed handout instruction. 108 women who presented to the family medicine outpatient clinic without having urine leakage as a chief complaint were selected. They were randomized to either the group who received interpersonal support and DVP as part of the PFME training (experimental group), or the group who received PFME with a printed handout instruction (control group). The effects were assessed with 1-h pad tests. A total of 99 patients (50 experimental, 49 control) completed the study. The patients' mean age was 55.35+/-9.60 years, ranging from 20 to 80 years. All patients without urinary leakage listed as a chief complaint exhibited more or less urine leakage during the 1-h pad test. A significant decrease in the weight of 1-h pad test from baseline was observed in the experimental group (p<0.001) compared to the control group (p=0.514). Interpersonal support and DVP as part of the PFME training is more effective than PFME with a printed handout instruction. PFME, performed correctly and consistently, is effective even in patients who have very few symptoms of SUI.

  17. 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....

  18. Solar Energy Gain and Space-Heating Energy Supply Analyses for Solid-Wall Dwelling Retrofitted with the Experimentally Achievable U-value of Novel Triple Vacuum Glazing

    Directory of Open Access Journals (Sweden)

    Saim Memon

    2017-06-01

    Full Text Available A considerable effort is devoted to devising retrofit solutions for reducing space-heating energy in the domestic sector. Existing UK solid-wall dwellings, which have both heritage values and historic fabric, are being improved but they tend to have meagre thermal performance, partly, due to the heat-loss through glazings. This paper takes comparative analyses approach to envisage space-heating supply required in order to maintain thermal comfort temperatures and attainable solar energy gains to households with the retrofit of an experimentally achievable thermal performance of the fabricated sample of triple vacuum glazing to a UK solid-wall dwelling. 3D dynamic thermal models (timely regimes of heating, occupancy, ventilation and internal heat gains of an externally-insulated solid-wall detached dwelling with a range of existing glazing types along with triple vacuum glazings are modelled. A dramatic decrease of space-heating load and moderate increase of solar gains are resulted with the dwelling of newly achievable triple vacuum glazings (having centre-of-pane U-value of 0.33 Wm-2K-1 compared to conventional glazing types. The space-heating annual cost of single glazed dwellings was minimised to 15.31% (≈USD 90.7 with the retrofit of triple-vacuum glazings. An influence of total heat-loss through the fabric of solid-wall dwelling was analysed with steady-state calculations which indicates a fall of 10.23 % with triple vacuum glazings compared to single glazings.

  19. Delay discounting and response disinhibition under acute experimental stress in women with borderline personality disorder and adult attention deficit hyperactivity disorder.

    Science.gov (United States)

    Krause-Utz, A; Cackowski, S; Daffner, S; Sobanski, Esther; Plichta, Michael M; Bohus, M; Ende, G; Schmahl, C

    2016-11-01

    Impulsivity is a core feature of borderline personality disorder (BPD) and attention deficit hyperactivity disorder (ADHD). In BPD, impulsive behavior primarily occurs under acute stress; impulse control deficits under non-stress conditions may be partly related to co-morbid ADHD. We aimed to investigate whether acute experimental stress has an impact on self-reported impulsivity, response inhibition (action withholding, action cancelation) and delay discounting in BPD compared to ADHD. Thirty female BPD patients, 28 female ADHD patients (excluding patients with co-morbid BPD and ADHD), and 30 female healthy controls (HC) completed self-reports and behavioral measures of impulsivity (IMT, assessing action withholding; GoStop, measuring action cancelation, Delay Discounting Task) under baseline conditions and after an experimental stress induction (Mannheim Multicomponent Stress Test). Both patient groups reported higher impulsivity than HC, ADHD reported higher trait impulsivity than BPD. On the IMT, ADHD showed significant action-withholding deficits under both conditions, while BPD performed significantly worse than HC under stress. In BPD but not ADHD and HC, action-withholding deficits (IMT) were significantly increased under stress compared to baseline, while no group/stress effects were found for action cancelation (GoStop). Delay discounting was significantly more pronounced in BPD than in HC (no stress effect was found). In BPD, behavioral deficits in action withholding (but not in action cancelation) appear to be influenced by acute experimental stress. Delay discounting seems to be a general feature of BPD, independent of co-morbid ADHD and acute stress, possibly underlying typical expressions of behavioral impulsivity in the disorder.

  20. Cardioprotective effect of Nerium oleander flower against isoproterenol-induced myocardial oxidative stress in experimental rats.

    Science.gov (United States)

    Gayathri, Veeraraghavan; Ananthi, Subhash; Chandronitha, Chandranayagam; Ramakrishnan, Ganapathy; Lakshmisundaram, Raman; Sundaram, Raman Lakshmi; Vasanthi, Hannah R

    2011-03-01

    Nerium oleander Linn (NOL) an evergreen shrub belonging to the Apocynaceae family has been reported to have a wide spectrum of bioactivities. In in vitro study, the free radical scavenging potential of the hydroethanolic extract of N oleander Linn (ENO) flower and its fractions (glycosidic and nonglycosidic) were studied using 2, 2(')-azino-di [3-ethylbenzthiazoline sulphonate] (ABTS(*+) ) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH*) scavenging assay. ENO exhibited better radical scavenging activities than its fractions. Furthermore, the cardioprotective role of ENO (10, 30, 100 mg/kg, per oral [po]) was tested against isoproterenol-induced myocardial toxicity (ISO, 120 mg/kg per day, subcutaneously [sc], for 2 days at 48 hours interval) in experimental rats when compared to propranolol (5 mg/kg, po) which was the standard. Pretreatment with ENO (10, 30, and 100 mg/kg) and propranolol for 2 weeks followed by ISO challenge in rats prevented the elevation of marker enzymes such as lactate dehydrogenase (LDH), γ-glutamyl transferase (GGT), creatine kinase (CK-MB and creatine phosphokinase [CPK]), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) in plasma. In addition, pretreatment with ENO and propranolol significantly attenuated the lipid peroxidation by maintaining the levels of enzymatic (superoxide dismutase and glutathione peroxidase) and nonenzymatic antioxidants (reduced glutathione and nitrite), which was also confirmed histologically. Taken together, the current study indicates that the hydroalcoholic extract of N oleander Linn flowers aid in cardioprotection probably by improving the antioxidant defense system during experimental myocardial necrosis.

  1. Vigas mistas de madeira de reflorestamento e bambu laminado colado: análise teórica e experimental Composite beams of reforestation wood and glue-laminated bamboo: theoretical and experimental analyses

    Directory of Open Access Journals (Sweden)

    Humberto C. Lima Júnior

    2001-12-01

    Full Text Available Neste trabalho, apresenta-se e se discute a análise teórica e experimental de vigas de madeira, reforçadas com bambu. Para tanto, o comportamento mecânico de cinco vigas mistas e duas de madeira foi estudado. A parte interna das vigas mistas foi constituída de Pinus elliottii e o reforço de bambu Dendrocalamus giganteus; este reforço foi disposto tanto na parte inferior como na superior das vigas, além de analisadas diferentes espessuras de reforço. São apresentadas curvas carga vs. deslocamentos e carga vs. deformação. Observou-se aumento da ordem de 50% na rigidez das vigas de Pinus elliottii, quando da presença do reforço de bambu. Finalmente, um estudo numérico em que se utilizou o método dos elementos finitos é apresentado, observando-se boa correlação entre os valores numéricos e experimentais.This paper presents and discusses the experimental and theoretical analyses of layer composite beams of wood strengthened with bamboo. For this, the mechanical behavior of five composite beams and two wood beams was studied. The beam's stuffing was composed of Pinus elliottii and the reinforcement of bamboo Dendrocalamus giganteus. The bamboo reinforcement was placed on the top and at the bottom of the beams. Different thicknesses of reinforcement were investigated. Curves of load vs. displacement and load vs. strain are presented. An increase of 50% was observed in the stiffness, when the composite beams are compared with the wood one. Finally, a numerical study was carried out applying the finite element method and a good agreement was observed between the theoretical and experimental values.

  2. Mitochondrial dysfunction, oxidative stress and apoptosis revealed by proteomic and transcriptomic analyses of the striata in two mouse models of Parkinson’s disease

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Mark H.; Qian, Weijun; Wang, Haixing; Petyuk, Vladislav A.; Bloom, Joshua S.; Sforza, Daniel M.; Lacan, Goran; Liu, Dahai; Khan, Arshad H.; Cantor, Rita M.; Bigelow, Diana J.; Melega, William P.; Camp, David G.; Smith, Richard D.; Smith, Desmond J.

    2008-02-10

    The molecular mechanisms underlying the changes in the nigrostriatal pathway in Parkinson disease (PD) are not completely understood. Here we use mass spectrometry and microarrays to study the proteomic and transcriptomic changes in the striatum of two mouse models of PD, induced by the distinct neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and methamphetamine (METH). Proteomic analyses resulted in the identification and relative quantification of 912 proteins with two or more unique peptides and 85 proteins with significant abundance changes following neurotoxin treatment. Similarly, microarray analyses revealed 181 genes with significant changes in mRNA following neurotoxin treatment. The combined protein and gene list provides a clearer picture of the potential mechanisms underlying neurodegeneration observed in PD. Functional analysis of this combined list revealed a number of significant categories, including mitochondrial dysfunction, oxidative stress response and apoptosis. Additionally, codon usage and miRNAs may play an important role in translational control in the striatum. These results constitute one of the largest datasets integrating protein and transcript changes for these neurotoxin models with many similar endpoint phenotypes but distinct mechanisms.

  3. Rock core-based pre-stress evaluation experimental validation: A case study on Yutengping Sandstone as CO2 storage reservoir rock

    Directory of Open Access Journals (Sweden)

    Jian-Hong Wu

    2017-01-01

    Full Text Available Yutengping Sandstone in Tieh-chan-shan, Taiwan is a potential reservoir for geological CO2 storage. Cyclic loadings were applied to rock samples taken from an outcrop to create artificial pre-stress. The pre-stress evaluation accuracies using two core-based techniques, acoustic emission (AE and deformation rate analysis (DRA, were investigated under different pre-stresses, delay times and curing temperatures. The experimental results validate the pre-stress evaluations using AE and DRA. The delay time and curing temperature were shown to have minor impacts on the measurement accuracy. However, although both axial strain and lateral strain can be used in DRA, the stress memory fades as the delay time increases. Therefore, delay time, which represents the time from the borehole drilling to the DRA test, must be carefully considered when applying these techniques to evaluate the in situ stress of Yutengping sandstone.

  4. Evidence of oxidative stress in brain and liver of young rats submitted to experimental galactosemia.

    Science.gov (United States)

    Castro, Márcia B; Ferreira, Bruna K; Cararo, José Henrique; Chipindo, Adália E; Magenis, Marina L; Michels, Monique; Danielski, Lucinéia G; de Oliveira, Marcos R; Ferreira, Gustavo C; Streck, Emilio L; Petronilho, Fabricia; Schuck, Patrícia F

    2016-12-01

    Galactosemia is a disorder of galactose metabolism, leading to the accumulation of this carbohydrate. Galactosemic patients present brain and liver damage. For evaluated oxidative stress, 30-day-old males Wistar rats were divided into two groups: galactose group, that received a single injection of this carbohydrate (5 μmol/g), and control group, that received saline 0.9 % in the same conditions. One, twelve or twenty-four hours after the administration, animals were euthanized and cerebral cortex, cerebellum, and liver were isolated. After one hour, it was found a significant increase in TBA-RS levels, nitrate and nitrite and protein carbonyl contents in cerebral cortex, as well as protein carbonyl content in the cerebellum and in hepatic level of TBA-RS, and a significant decrease in nitrate and nitrite contents in cerebellum. TBA-RS levels were also found increased in all studied tissues, as well as nitrate and nitrite contents in cerebral cortex and cerebellum, that also present increased protein carbonyl content and impairments in the activity of antioxidant enzymes of rats euthanized at twelve hours. Finally, animals euthanized after twenty-four hours present an increase of TBA-RS levels in studied tissues, as well as the protein carbonyl content in cerebellum and liver. These animals also present an increased nitrate and nitrite content and impairment of antioxidant enzymes activities. Taken together, our data suggest that acute galactose administration impairs redox homeostasis in brain and liver of rats.

  5. Time Domain Strain/Stress Reconstruction Based on Empirical Mode Decomposition: Numerical Study and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Jingjing He

    2016-08-01

    Full Text Available Structural health monitoring has been studied by a number of researchers as well as various industries to keep up with the increasing demand for preventive maintenance routines. This work presents a novel method for reconstruct prompt, informed strain/stress responses at the hot spots of the structures based on strain measurements at remote locations. The structural responses measured from usage monitoring system at available locations are decomposed into modal responses using empirical mode decomposition. Transformation equations based on finite element modeling are derived to extrapolate the modal responses from the measured locations to critical locations where direct sensor measurements are not available. Then, two numerical examples (a two-span beam and a 19956-degree of freedom simplified airfoil are used to demonstrate the overall reconstruction method. Finally, the present work investigates the effectiveness and accuracy of the method through a set of experiments conducted on an aluminium alloy cantilever beam commonly used in air vehicle and spacecraft. The experiments collect the vibration strain signals of the beam via optical fiber sensors. Reconstruction results are compared with theoretical solutions and a detailed error analysis is also provided.

  6. Experimental Study on the Effects of Stress Variations on the Permeability of Feldspar-Quartz Sandstone

    Directory of Open Access Journals (Sweden)

    Fugang Wang

    2017-01-01

    Full Text Available The multistage and discontinuous nature of the injection process used in the geological storage of CO2 causes reservoirs to experience repeated loading and unloading. The reservoir permeability changes caused by this phenomenon directly impact the CO2 injection process and the process of CO2 migration in the reservoirs. Through laboratory experiments, variations in the permeability of sandstone in the Liujiagou formation of the Ordos CO2 capture and storage (CCS demonstration project were analyzed using cyclic variations in injection pressure and confining pressure and multistage loading and unloading. The variation in the micropore structure and its influence on the permeability were analyzed based on micropore structure tests. In addition, the effects of multiple stress changes on the permeability of the same type of rock with different clay minerals content were also analyzed. More attention should be devoted to the influence of pressure variations on permeability in evaluations of storage potential and studies of CO2 migration in reservoirs in CCS engineering.

  7. Experimental Investigation of the Effect of Bedding Planes on Hydraulic Fracturing Under True Triaxial Stress

    Science.gov (United States)

    Huang, Bingxiang; Liu, Jiangwei

    2017-10-01

    A bedding plane effect occurs when hydraulic fractures encounter the bedding plane. True triaxial hydraulic fracturing experiments were conducted with test blocks containing bedding planes. The effects of bedding plane properties and stress state on fracture propagation were analyzed. When hydraulic fracture encounters the bedding plane in sedimentary stratum, it usually propagates along the bedding plane at first. When the hydraulic pressure increases to a critical value in the direction of main hydraulic fracture, the main hydraulic fracture continues propagating along the original direction. The length of the long axial of the hydraulic fracture propagating along the bedding plane is greater than the length of the main hydraulic fracture before penetrating the bedding plane, and both of them are greater than the length of the main hydraulic fracture after penetrating the bedding plane. Three-dimensional propagation models were established. Three propagation forms of hydraulic fractures existed when encountering bedding planes: (1) propagation along the bedding plane; (2) initial propagation along the bedding plane followed by penetration of the bedding plane and propagation along the principal direction; and (3) direct penetration of the bedding plane and propagation along the principal direction.

  8. Permeability of concrete under thermal and compressive stress influence; an experimental study

    Directory of Open Access Journals (Sweden)

    Lun H.

    2013-09-01

    Full Text Available In recent years the permeability was found as one of the main parameters affecting the durability of concrete. Especially in concrete at high temperatures in case of fire loading, the interaction of thermal/mechanical loading and fluid transfer strongly influences degradation of mechanical properties within concrete and spalling of near-surface concrete layers. To understand the change in transport properties of concrete, a new experimental setup was developed, allowing us to conduct permeability tests under uniaxial compressive loading up to 20 MPa and thermal condition up to 350 °C. Based on the obtained results, the effect of both mechanical and thermal loading on the effective transport properties is highlighted and relations to more simplified test setups, disregarding mechanical loading and/or conducting the permeability test at room temperature giving the residual permeability, are established.

  9. Improved prediction of peroxisomal PTS1 proteins from genome sequences based on experimental subcellular targeting analyses as exemplified for protein kinases from Arabidopsis.

    Science.gov (United States)

    Ma, Changle; Reumann, Sigrun

    2008-01-01

    Due to current experimental limitations in peroxisome proteome research, the identification of low-abundance regulatory proteins such as protein kinases largely relies on computational protein prediction. To test and improve the identification of regulatory proteins by such a prediction-based approach, the Arabidopsis genome was screened for genes that encode protein kinases with predicted type 1 or type 2 peroxisome targeting signals (PTS1 or PTS2). Upon transient expression in onion epidermal cells, the predicted PTS1 domains of four of the seven protein kinases re-directed the reporter protein, enhanced yellow green fluorescent (EYFP), to peroxisomes and were thus verified as functional PTS1 domains. The full-length fusions, however, remained cytosolic, suggesting that PTS1 exposure is induced by specific signals. To investigate why peroxisome targeting of three other kinases was incorrectly predicted and ultimately to improve the prediction algorithms, selected amino acid residues located upstream of PTS1 tripeptides were mutated and the effect on subcellular targeting of the reporter protein was analysed. Acidic residues in close proximity to major PTS1 tripeptides were demonstrated to inhibit protein targeting to plant peroxisomes even in the case of the prototypical PTS1 tripeptide SKL>, whereas basic residues function as essential auxiliary targeting elements in front of weak PTS1 tripeptides such as SHL>. The functional characterization of these inhibitory and essential enhancer-targeting elements allows their consideration in predictive algorithms to improve the prediction accuracy of PTS1 proteins from genome sequences.

  10. A Study on the gas productivity by using Experimental Results of Stress-induced Permeability Change in Coal Seam

    Science.gov (United States)

    Kang, I. O.; Kim, K. H.; Han, J. M.; Lee, S. M.

    2016-12-01

    Methane Production from coal has become one of the more interesting practices in recent years to produce hydrocarbons. In the United States in 2005, it is estimated that 11% of all gas produced is from coalbed. The permeability is a measure of the capability of a porous medium to transmit fluid thought a network of microscopic channels. The permeability in coal is a direct function of the cleat volume. Since the volume of cleat changes with effect on the effective stress and sorption characteristics for production duration, the permeability also produces the alteration. Thus, to definitely estimate the gas production ability of the coal, it is essential that we especially understand changing aspects of permeability for production duration. Many researchers suggested the empirical equation to describe the effect of matrix shrinkage and effective stress. However, the past research associated with permeability change in coal focused on experimental results at a certain temperature.In this study, we have investigated the change of the sorption-induced permeability in pressure change with depth, an experimental approach considering temperature influence at the certain depth may be followed. Based on the received core from CBM field, we conducted the experiment both sorption and permeability according to the various pressure and temperatures.Firstly, experiment of the CH4 sorption was performed in the temperature ranged from 59℉ to 113℉ in the pressure ranges from 14.7 psia to 1,299 psia. Ot was found that CH3 isotherms display a normal Langmuir-type behavior from experiment ranges. In order to understand the effect of adsorption of CH4 in the change of sorption-induced permeability, we measured the permeability at the various pressures. When the pressure was increased by 100 psia, the results showed that the permeability alteration rate was 9.7% in reduction. Meanwhile, the permeability change rate was higher for a better affinity gas at lower temperature. Based on

  11. Fecal microbiota transplantation (FMT) could reverse the severity of experimental necrotizing enterocolitis (NEC) via oxidative stress modulation.

    Science.gov (United States)

    Li, Xiaomei; Li, Xiaowen; Shang, Qingjuan; Gao, Zongwei; Hao, Fabao; Guo, Hongjie; Guo, Chunbao

    2017-07-01

    Fecal microbiota transplantation (FMT) has been used successfully to treat a variety of gastroenterological diseases. The alterations of microbiota in mouse models of necrotizing enterocolitis (NEC) as well as in patients suggested the possibility of treating NEC with FMT. Here we show that FMT caused an improvement in the histopathology and symptoms of NEC in WT mice, but not Grx1-/- mice. FMT eliminated O2•- production and promoted NO production in experimental NEC mice though the modulation of S-glutathionylation of eNOS (eNOS-SSG). FMT decreased the extent of TLR4-mediated proinflammatory signaling though TLR9 in the intestinal mucosa tissue. FMT also suppressed intestinal apoptosis and bacterial translocation across the intestinal barrier, which was accompanied by decreased inflammatory cytokine levels, altered bacterial microbiota, and regulated lymphocyte proportions. FMT is effective in a mouse model of NEC through the modulation of oxidative stress and reduced colon inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Bioengineer effects on understory species richness, diversity, and composition change along an environmental stress gradient: Experimental and mensurative evidence

    Science.gov (United States)

    Watt, Cortney A.; Scrosati, Ricardo A.

    2013-05-01

    Canopy-forming bioengineer species are commonly assumed to increase local species richness and diversity. We tested this notion by investigating the effects of fucoid seaweed canopies on understory communities along rocky intertidal elevation gradients in Atlantic Canada. Such gradients exhibit increasing thermal extremes and variation from low to high elevations, and are broadly used in stress gradient studies. A manipulative experiment created canopy and no-canopy treatments at the low, middle, and high intertidal zones, eliminating all species (except fucoid canopies) from replicate quadrats. After recolonization, overall richness and diversity (considering all primary producers and consumers) were higher under canopies than uncovered by canopies at the high and middle zones, but no effects occurred at the low zone. Similarly, species composition was affected by canopies at the high and middle zones, but not at the low zone. A mensurative study that surveyed the full range of canopy cover (0-100%) using nearly five times more quadrats from pristine areas yielded the same results: richness and diversity increased with canopy cover at the high and middle zones (approaching stabilization toward high cover values), but no effects occurred at the low zone. Lack of canopy effects at low elevations is related to mild habitat conditions, which canopies are unable to modify, while positive effects at higher elevations relate to the capacity of canopies to ameliorate harsh conditions. This is the first time that a combined experimental and mensurative approach shows that the same bioengineer species affect overall species richness, diversity, and composition differently along a stress gradient. Overall, protecting canopy-forming bioengineers to preserve local biodiversity should be most effective in stressful environments.

  13. S-Allylmercapto-N-acetylcysteine (ASSNAC) protects cultured nerve cells from oxidative stress and attenuates experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Savion, Naphtali; Izigov, Nira; Morein, Milana; Pri-Chen, Sarah; Kotev-Emeth, Shlomo

    2014-11-07

    Oxidative stress and/or low cellular glutathione are associated with development and progression of neurodegenerative diseases. We have shown that S-allylmercapto-N-acetylcysteine (ASSNAC) up-regulates the level of glutathione and phase II detoxifying enzymes in cultured vascular endothelial cells. The present study demonstrates that exposure of nerve cell lines to ASSNAC significantly increases the cellular level of glutathione probably via activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and protects the cells from tBuOOH-induced cytotoxicity. Furthermore, ASSNAC increases the level of mice spinal cord and brain glutathione (by 54% and 47%, respectively) and attenuates the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in mice. In conclusion, these data implicate ASSNAC to protect nerve cells, both in vitro and in vivo, from oxidative stress and thereby to attenuate the clinical symptoms of EAE, suggesting its potential use for the treatment of neurodegenerative diseases. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Flagellar swimming in viscoelastic fluids: role of fluid elastic stress revealed by simulations based on experimental data.

    Science.gov (United States)

    Li, Chuanbin; Qin, Boyang; Gopinath, Arvind; Arratia, Paulo E; Thomases, Becca; Guy, Robert D

    2017-10-01

    Many important biological functions depend on microorganisms' ability to move in viscoelastic fluids such as mucus and wet soil. The effects of fluid elasticity on motility remain poorly understood, partly because the swimmer strokes depend on the properties of the fluid medium, which obfuscates the mechanisms responsible for observed behavioural changes. In this study, we use experimental data on the gaits of Chlamydomonas reinhardtii swimming in Newtonian and viscoelastic fluids as inputs to numerical simulations that decouple the swimmer gait and fluid type in order to isolate the effect of fluid elasticity on swimming. In viscoelastic fluids, cells employing the Newtonian gait swim faster but generate larger stresses and use more power, and as a result the viscoelastic gait is more efficient. Furthermore, we show that fundamental principles of swimming based on viscous fluid theory miss important flow dynamics: fluid elasticity provides an elastic memory effect that increases both the forward and backward speeds, and (unlike purely viscous fluids) larger fluid stress accumulates around flagella moving tangent to the swimming direction, compared with the normal direction. © 2017 The Author(s).

  15. Experimental study on stress corrosion crack propagation rate of FV520B in carbon dioxide and hydrogen sulfide solution

    Science.gov (United States)

    Qin, Ming; Li, Jianfeng; Chen, Songying; Qu, Yanpeng

    FV520B steel is a kind of precipitation hardening Martensitic stainless steel, it has high-strength, good plasticity and good corrosion resistance. Stress corrosion cracking (SCC) is one of the main corrosion failure mode for FV520B in industrial transportation of natural gas operation. For a better understanding the effect on SCC of FV520B, the improved wedge opening loading (WOL) specimens and constant displacement loading methods were employed in experimental research in carbon dioxide and hydrogen sulfide solution. The test results showed that the crack propagation rate is 1.941 × 10-7-5.748 × 10-7 mm/s, the stress intensity factor KISCC is not more than 36.83 MPa √{ m } . The rate increases with the increasing of the crack opening displacement. Under the condition of different initial loading, KISCC generally shows a decreasing tendency with the increase in H2S concentration, and the crack propagation rate showed an increasing trend substantially. For the enrichment of sulfur ion in the crack tip induced the generation of pitting corrosion, promoting the surrounding metal formed the corrosion micro batteries, the pit defects gradually extended and connected with the adjacent pit to form a small crack, leading to further propagation till cracking happened. Fracture microscopic morphology displayed typical brittle fracture phenomena, accompanying with trans-granular cracking, river shape and sector, many second cracks on the fracture surface.

  16. Stress

    OpenAIRE

    Jensen, Line Skov; Lova, Lotte; Hansen, Zandra Kulikovsky; Schønemann, Emilie; Larsen, Line Lyngby; Colberg Olsen, Maria Sophia; Juhl, Nadja; Magnussen, Bogi Roin

    2012-01-01

    Stress er en tilstand som er meget omdiskuteret i samfundet, og dette besværliggør i en vis grad konkretiseringen af mulige løsningsforslag i bestræbelsen på at forebygge den såkaldte folkesygdom. Hovedkonklusionen er, at selv om der bliver gjort meget for at forebygge, er der ikke meget der aktivt kan sættes i værk for at reducere antallet af stressramte, før en fælles forståelse af stressårsager og effektiv stresshåndtering er fremlagt. Problemformuleringen er besvaret gennem en undersø...

  17. Lycopene Ameliorates Experimental Colitis in Rats via Reducing Apoptosis and Oxidative Stress.

    Science.gov (United States)

    Gul Baykalir, Burcu; Aksit, Dilek; Dogru, Mustafa Selim; Hanım Yay, Arzu; Aksit, Hasan; Seyrek, Kamil; Attesahin, Ahmet

    2017-07-19

    Inflammatory bowel disease (IBD) is an inflammatory disorder involving colitis. Lycopene is a naturally occurring carotenoid that has attracted considerable attention as a potential chemopreventive agent. The impact of lycopene on colitis is currently unknown. The aim of this study was to investigate the protective effects of lycopene in a rat model of colitis induced by acetic acid. The animals were randomly divided into the following five groups: the control group, colitis group, colitis + sulfasalazine group as a positive control group, colitis + lycopene and lycopene groups. Colonic mucosal injury was assessed by biochemical and histopathological examinations. Malondialdehyde (MDA), superoxide dismutase (SOD) activity, total antioxidant status (TAS), ceruloplasmin (CPN), total sialic acid and iron (Fe) levels were evaluated in blood samples. MDA, SOD, TAS and DNA fragmentation levels were also measured in colon tissues. MDA (p lycopene in the colitis decreased MDA, total sialic acid and DNA fragmentation levels, while SOD activity (p lycopene ameliorated the biochemical and pathological alterations caused by colitis. The results obtained in this study indicate that lycopene may exert protective effects in experimental colitis and might, therefore, be useful for treatment of IBD.

  18. Aloe vera gel protects liver from oxidative stress-induced damage in experimental rat model.

    Science.gov (United States)

    Nahar, Taslima; Uddin, Borhan; Hossain, Shahdat; Sikder, Abdul Mannan; Ahmed, Sohel

    2013-05-07

    Aloe vera is a semi-tropical plant of Liliaceae family which has a wide range of applications in traditional medicine. In the present study, we sought to investigate the heptaoprotective potential of Aloe vera gel as a diet supplement. To achieve this goal, we have designed in vitro and in vivo experimental models of chemical-induced liver damage using male Sprague-Dawley rat. In the in vitro model, its effect was evaluated on Fenton's reaction-induced liver lipid peroxidation. Co-incubation with gel significantly reduced the generation of liver lipid peroxide (LPO). Next, to see the similar effect in vivo, gel was orally administered to rats once daily for 21 successive days. Following 1 hour of the last administration of gel, rats were treated with intra-peritoneal injection of CCl4. Dietary gel showed significant hepatoprotection against CCl4-induced damage as evident by restoration of liver LPO, serum transaminases, alkaline phosphatase, and total bilirubin towards near normal. The beneficial effects were pronounced with the doses used (400 and 800 mg/kg body weight). Besides, we did not observe any significant drop in serum albumin, globulin as well as total protein levels of gel-administered rats. Histopathology of the liver tissue further supported the biochemical findings confirming the hepatoprotective potential of dietary gel.

  19. Increased oxidative stress and severe arterial remodeling induced by permanent high-flow challenge in experimental pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Fadel Elie

    2011-09-01

    Full Text Available Abstract Background Involvement of inflammation in pulmonary hypertension (PH has previously been demonstrated and recently, immune-modulating dendritic cells (DCs infiltrating arterial lesions in patients suffering from idiopathic pulmonary arterial hypertension (IPAH and in experimental monocrotaline-induced PH have been reported. Occurrence of perivascular inflammatory cells could be linked to local increase of oxidative stress (OS, as it has been shown for systemic atherosclerosis. The impact of OS on vascular remodeling in PH is still to be determined. We hypothesized, that augmented blood-flow could increase OS and might thereby contribute to DC/inflammatory cell-recruitment and smooth-muscle-cell-proliferation. Methods We applied a monocrotaline-induced PH-model and combined it with permanent flow-challenge. Thirty Sprague-Dawley rats were assigned to following groups: control, monocrotaline-exposure (MCT, monocrotaline-exposure/pneumonectomy (MCT/PE. Results Hemodynamic exploration demonstrated most severe effects in MCT/PE, corresponding in histology to exuberant medial and adventitial remodeling of pulmonary muscular arteries, and intimal remodeling of smaller arterioles; lung-tissue PCR evidenced increased expression of DCs-specific fascin, CD68, proinflammatory cytokines (IL-6, RANTES, fractalkine in MCT/PE and to a lesser extent in MCT. Major OS enzyme NOX-4 was maximal in MCT/PE. Antioxidative stress enzymes Mn-SOD and glutathion-peroxidase-1 were significantly elevated, while HO-1 showed maximal expression in MCT with significant decrease in MCT/PE. Catalase was decreased in MCT and MCT/PE. Expression of NOX-4, but also of MN-SOD in MCT/PE was mainly attributed to a highly increased number of interstitial and perivascular CXCR4/SDF1 pathway-recruited mast-cells. Stress markers malonedialdehyde and nitrotyrosine were produced in endothelial cells, medial smooth muscle and perivascular leucocytes of hypertensive vasculature

  20. Increased oxidative stress and severe arterial remodeling induced by permanent high-flow challenge in experimental pulmonary hypertension.

    Science.gov (United States)

    Dorfmüller, Peter; Chaumais, Marie-Camille; Giannakouli, Maria; Durand-Gasselin, Ingrid; Raymond, Nicolas; Fadel, Elie; Mercier, Olaf; Charlotte, Frédéric; Montani, David; Simonneau, Gérald; Humbert, Marc; Perros, Frédéric

    2011-09-09

    Involvement of inflammation in pulmonary hypertension (PH) has previously been demonstrated and recently, immune-modulating dendritic cells (DCs) infiltrating arterial lesions in patients suffering from idiopathic pulmonary arterial hypertension (IPAH) and in experimental monocrotaline-induced PH have been reported. Occurrence of perivascular inflammatory cells could be linked to local increase of oxidative stress (OS), as it has been shown for systemic atherosclerosis. The impact of OS on vascular remodeling in PH is still to be determined. We hypothesized, that augmented blood-flow could increase OS and might thereby contribute to DC/inflammatory cell-recruitment and smooth-muscle-cell-proliferation. We applied a monocrotaline-induced PH-model and combined it with permanent flow-challenge. Thirty Sprague-Dawley rats were assigned to following groups: control, monocrotaline-exposure (MCT), monocrotaline-exposure/pneumonectomy (MCT/PE). Hemodynamic exploration demonstrated most severe effects in MCT/PE, corresponding in histology to exuberant medial and adventitial remodeling of pulmonary muscular arteries, and intimal remodeling of smaller arterioles; lung-tissue PCR evidenced increased expression of DCs-specific fascin, CD68, proinflammatory cytokines (IL-6, RANTES, fractalkine) in MCT/PE and to a lesser extent in MCT. Major OS enzyme NOX-4 was maximal in MCT/PE. Antioxidative stress enzymes Mn-SOD and glutathion-peroxidase-1 were significantly elevated, while HO-1 showed maximal expression in MCT with significant decrease in MCT/PE. Catalase was decreased in MCT and MCT/PE. Expression of NOX-4, but also of MN-SOD in MCT/PE was mainly attributed to a highly increased number of interstitial and perivascular CXCR4/SDF1 pathway-recruited mast-cells. Stress markers malonedialdehyde and nitrotyrosine were produced in endothelial cells, medial smooth muscle and perivascular leucocytes of hypertensive vasculature. Immunolabeling for OX62, CD68 and actin revealed

  1. Carbon fiber based composites stress analysis. Experimental and computer comparative studies

    Science.gov (United States)

    Sobek, M.; Baier, A.; Buchacz, A.; Grabowski, Ł.; Majzner, M.

    2015-11-01

    Composite materials used nowadays for the production of composites are the result of advanced research. This allows assuming that they are among the most elaborate tech products of our century. That fact is evidenced by the widespread use of them in the most demanding industries like aerospace and space industry. But the heterogeneous materials and their advantages have been known to mankind in ancient times and they have been used by nature for millions of years. Among the fibers used in the industry most commonly used are nylon, polyester, polypropylene, boron, metal, glass, carbon and aramid. Thanks to their physical properties last three fiber types deserve special attention. High strength to weight ratio allow the use of many industrial solutions. Composites based on carbon and glass fibers are widely used in the automotive. Aramid fibers ideal for the fashion industry where the fabric made from the fibers used to produce the protective clothing. In the paper presented issues of stress analysis of composite materials have been presented. The components of composite materials and principles of composition have been discussed. Particular attention was paid to the epoxy resins and the fabrics made from carbon fibers. The article also includes basic information about strain measurements performed on with a resistance strain gauge method. For the purpose of the laboratory tests a series of carbon - epoxy composite samples were made. For this purpose plain carbon textile was used with a weight of 200 g/mm2 and epoxy resin LG730. During laboratory strain tests described in the paper Tenmex's delta type strain gauge rosettes were used. They were arranged in specific locations on the surface of the samples. Data acquisition preceded using HBM measurement equipment, which included measuring amplifier and measuring head. Data acquisition was performed using the Easy Catman. In order to verify the results of laboratory tests numerical studies were carried out in a

  2. The PIN gene family in cotton (Gossypium hirsutum): genome-wide identification and gene expression analyses during root development and abiotic stress responses.

    Science.gov (United States)

    He, Peng; Zhao, Peng; Wang, Limin; Zhang, Yuzhou; Wang, Xiaosi; Xiao, Hui; Yu, Jianing; Xiao, Guanghui

    2017-07-03

    Cell elongation and expansion are significant contributors to plant growth and morphogenesis, and are often regulated by environmental cues and endogenous hormones. Auxin is one of the most important phytohormones involved in the regulation of plant growth and development and plays key roles in plant cell expansion and elongation. Cotton fiber cells are a model system for studying cell elongation due to their large size. Cotton is also the world's most utilized crop for the production of natural fibers for textile and garment industries, and targeted expression of the IAA biosynthetic gene iaaM increased cotton fiber initiation. Polar auxin transport, mediated by PIN and AUX/LAX proteins, plays a central role in the control of auxin distribution. However, very limited information about PIN-FORMED (PIN) efflux carriers in cotton is known. In this study, 17 PIN-FORMED (PIN) efflux carrier family members were identified in the Gossypium hirsutum (G. hirsutum) genome. We found that PIN1-3 and PIN2 genes originated from the At subgenome were highly expressed in roots. Additionally, evaluation of gene expression patterns indicated that PIN genes are differentially induced by various abiotic stresses. Furthermore, we found that the majority of cotton PIN genes contained auxin (AuxREs) and salicylic acid (SA) responsive elements in their promoter regions were significantly up-regulated by exogenous hormone treatment. Our results provide a comprehensive analysis of the PIN gene family in G. hirsutum, including phylogenetic relationships, chromosomal locations, and gene expression and gene duplication analyses. This study sheds light on the precise roles of PIN genes in cotton root development and in adaption to stress responses.

  3. Comparative radiographic and resonance frequency analyses of the peri-implant tissue after dental implants placement using flap and flapless techniques: an experimental study on domestic pigs.

    Science.gov (United States)

    Vlahović, Zoran; Mihailović, Branko; Lazić, Zoran; Golubović, Mileta

    2013-06-01

    Flapless implant surgery has become very important issue during recent years, mostly thanks to computerization of dentistry and software planning of dental implants placements. The aim of this study was to compare flap and flapless surgical techniques for implant placement through radiographic and radiofrequency analyses. The experiment was made in five domestic pigs. Nine weeks following domestic pigs teeth extraction, implants were placed, on the right side using surgical technique flap, and flapless on the left side. Digital dental Xrays were applied to determine primary dental implant stability quality (ISQ). At certain intervals, not later than three months, the experimental animals were sacrificed, and just before it, control X-rays were applied to measure dental implants stability. Radiographic analysis showed that peri-implant bone resorption in the first 4 weeks following placement implants with flap and flapless surgical techniques was negligible. After the 3 months, mean value of peri-implant bone resorption of the implants placed using flap tehnique was 1.86 mm, and of those placed using flapless tehnique was 1.13 mm. In relation to the primary dental implant stability in the first and second week there was an expected decrease in ISQ values, but it was less expressed in the dental implants placed using the flapless technique. In the third week the ISQ values were increased in the dental implants placed by using both techniques, but the increase in flapless implant placement was higher (7.4 ISQ) than in flap implant placement (1.5 ISQ). The upward trend continued in a 4-week period, and after 3 months the dental implant stability values in the implants placed using flap technique were higher than the primary stability for 7.1 ISQ, and in the implants placed using flapless technique were higher comparing to the primary stability for 10.1 ISQ units. Based on the results of radiographic and resonance frequency analyses it can be concluded that the flapless

  4. Comparative radiographic and resonance frequency analyses of the peri-implant tissue after dental implants placement using flap and flapless techniques: An experimental study on domestic pigs

    Directory of Open Access Journals (Sweden)

    Vlahović Zoran

    2013-01-01

    Full Text Available Background/Aim. Flapless implant surgery has become very important issue during recent years, mostly thanks to computerization of dentistry and software planning of dental implants placements. The aim of this study was to compare flap and flapless surgical techniques for implant placement through radiographic and radiofrequency analyses. Methods. The experiment was made in five domestic pigs. Nine weeks following domestic pigs teeth extraction, implants were placed, on the right side using surgical technique flap, and flapless on the left side. Digital dental Xrays were applied to determine primary dental implant stability quality (ISQ. At certain intervals, not later than three months, the experimental animals were sacrificed, and just before it, control X-rays were applied to measure dental implants stability. Results. Radiographic analysis showed that peri-implant bone resorption in the first 4 weeks following placement implants with flap and flapless surgical techniques was negligible. After the 3 months, mean value of peri-implant bone resorption of the implants placed using flap technique was 1.86 mm, and of those placed using flapless technique was 1.13 mm. In relation to the primary dental implant stability in the first and second week there was an expected decrease in ISQ values, but it was less expressed in the dental implants placed using the flapless technique. In the third week the ISQ values were increased in the dental implants placed by using both techniques, but the increase in flapless implant placement was higher (7.4 ISQ than in flap implant placement (1.5 ISQ. The upward trend continued in a 4- week period, and after 3 months the dental implant stability values in the implants placed using flap technique were higher than the primary stability for 7.1 ISQ, and in the implants placed using flapless technique were higher comparing to the primary stability for 10.1 ISQ units. Conclusion. Based on the results of radiographic and

  5. The effect of ultra-fast photopolymerisation of experimental composites on shrinkage stress, network formation and pulpal temperature rise.

    Science.gov (United States)

    Randolph, Luc D; Palin, William M; Watts, David C; Genet, Mathieu; Devaux, Jacques; Leloup, Gaetane; Leprince, Julian G

    2014-11-01

    to complement our previous work by testing the null hypotheses that with short curing times and high DC, TPO-based resin composites would exhibit (1) higher polymerization stresses and consequently display (2) higher temperature rise and (3) higher flexural modulus, flexural strength and hardness, compared to a conventional CQ-based experimental composite. Two experimental resin composites using either Lucirin-TPO or camphorquinone/DMAEMA as photoinitiators were prepared. Light curing was carried out using spectral outputs adapted to the absorption properties of each initiator. Different irradiation protocols were selected (0.5, 1, 3, 9 s at 500, 1000 and 2000 mW/cm(2) for Lucirin-TPO based composites and 20 or 40 s at 1000 mW/cm2 for Lucirin-TPO and camphorquinone-based composites). Degree of conversion (DC) was measured in real time by means of FT-NIR spectroscopy. Pulpal temperature rise (ΔT) was studied in a tooth model. Polymerization stress was monitored using the Bioman instrument. For cured specimens, flexural modulus and flexural strength were determined using a three point bending platform and Vickers hardness was determined with a microhardness indentor on samples prior to and after 24 h incubation in 75/25 ethanol/H2O. Premolars were restored with both materials and microleakage at the teeth/composite interfaces following restoration was assessed. Lucirin-TPO-based composites irradiated at radiant exposures of 3 J/cm(2) and more exhibited significantly higher DCs, associated with increased flexural moduli and hardness compared to CQ-based composites. For an ultra-short irradiation time of 1 s at 1000 mW/cm(2), TPO-composites displayed similar polymerization stresses compared to CQ-controls with yet a 25% increase for flexural modulus and 40% increase for hardness measured after EtOH/H2O sorption. Higher stress rates were however observed in all curing protocols compared to CQ-composites. Microleakage was similar between TPO and CQ-composites irradiated

  6. 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

  7. The effects of low thyroid hormone levels on the formation of stress gastritis: an experimental study on the rats.

    Science.gov (United States)

    Maralcan, Göktürk; Erkol, Hayri; Erkol, Zerrin; Yanar, Fatih; Plevin, Rebecca

    2008-04-01

    The aim of this study was to investigate the effect of low circulating thyroid hormone levels on the development of acute stress gastritis in rats. Sixty adult Sprague-Dawley rats were divided into six groups: Control group, surgically thyroidectomized group, stressed group, surgically thyroidectomized + stressed group, surgically thyroidectomized + T4 + stressed group, and surgically thyroidectomized + T3 + stressed group. Damage to the gastric mucosa was studied using millimetric acetate papers on photographs enlarged 3.5 times and the number and the size of the lesions was recorded. Acute stress gastritis was significantly increased in stress + surgically thyroidectomized rats as compared to rats that were only put under stress (group III) (stress gastritis scores; group IV: 44, group III: 16, pgastritis score in group VI was significantly decreased compared to rats in group IV (stress gastritis scores; group VI: 10, group IV: 44, pgastritis. This effect could be prevented by thyroid hormone replacement therapy.

  8. A Quasi-experimental outcomes analysis of a psychoeducation intervention for pregnant women with abuse-related posttraumatic stress.

    Science.gov (United States)

    Rowe, Heather; Sperlich, Mickey; Cameron, Heather; Seng, Julia

    2014-01-01

    To test the effectiveness of a trauma-specific, psychoeducational intervention for pregnant women with a history of childhood maltreatment on six intrapartum and postpartum psychological outcomes. Quasi-experimental study comparing women from a single-group, pretest-posttest pilot intervention study with women matched from a prospective observational study. Rural and university-based prenatal clinics. Pregnant women entered the study by responding to an advertisement or by referral from a maternity care provider. Women could take part whether or not they met posttraumatic stress disorder diagnostic criteria. Outcomes data exist for 17 pilot intervention study participants and 43 matched observational study participants. Participants in the observational study received usual care. Participants in the pilot intervention study received usual care plus the intervention, a fully manualized, self-study program supported by weekly phone tutoring sessions with a health professional. The National Women's Study PTSD Module, the Peritraumatic Dissociation Experience Questionnaire, the Perception of Care Questionnaire, the Postpartum Depression Screening Scale, the Postpartum Bonding Questionnaire, and a semantic differential appraisal of the labor experience. Participants in the intervention study had better scores on all measures. Differences in means between participants in the intervention study and participants in the observational study equated to medium effect sized for dissociation during labor, rating of labor experience, and perception of care in labor and small effect sizes for postpartum posttraumatic stress disorder (PTSD) symptoms, postpartum depression symptoms, and motherinfant bonding. This trauma-specific intervention reaches and benefits pregnant women with a history of childhood maltreatment. © 2014 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  9. Stemodia maritima L. Extract Decreases Inflammation, Oxidative Stress, and Alveolar Bone Loss in an Experimental Periodontitis Rat Model

    Directory of Open Access Journals (Sweden)

    Alrieta H. Teixeira

    2017-12-01

    Full Text Available Periodontitis is very prevalent worldwide and is one of the major causes of tooth loss in adults. About 80% of the worldwide population use medicinal plants for their health care. Stemodia maritima L. (S. maritima antioxidant and antimicrobial effects in vitro as well as anti-inflammatory properties. Herein, the potential therapeutic effect of S. maritima was assessed in rats subjected to experimental periodontitis (EP. EP was induced in female Wistar rats by nylon thread ligature around 2nd upper left molars for 11 days. Animals received (per os S. maritima (0.2; 1 or 5 mg/kg or vehicle (saline + DMSO 1 h before ligature and then once daily for 11 days. The naive group had no manipulation. After this time-point, the animals were terminally anesthetized, and the maxillae were removed for morphometric and histological analyzes (HE. Gingival tissues were dissected to cytokine levels detection (TNF-α, IL1-β, CINC-1, and IL-10, enzymes superoxide dismutase (SOD, and catalase (CAT analysis, as well as gene expression (TNF-α, IL-1β, RANK, and iNOS by qRT-PCR. Systemic parameters (weight variation, plasma levels of hepatic enzymes aspartate aminotransferase (AST and alanine aminotransferase (ALT, creatinine, total alkaline phosphatase (TALP, and bone alkaline phosphatase (BALP were performed. Histological analysis of the stomach, liver, kidney, and heart was also performed. S. maritima (5 mg/kg decreased alveolar bone loss, TNF-α and CINC-1 gingival levels, oxidative stress, and transcription of TNF-α, IL1-β, RANK, and iNOS genes. It elevated both BALP activity and IL-10 gingival levels. The animals showed no any signs of toxicity. In conclusion, S. maritima reduced pro-inflammatory cytokine production, oxidative stress, and alveolar bone loss in a pre-clinical trial of periodontitis. S. maritima is a potential tool for controlling the development of periodontitis.

  10. Effects of isolated vitamin B6 supplementation on oxidative stress and heart function parameters in experimental hyperhomocysteinemia

    Directory of Open Access Journals (Sweden)

    Roberta Hack Mendes

    2017-07-01

    Full Text Available Introduction: The purpose of this study was to investigate the effects of isolated vitamin B6 (VB6 supplementation on experimental hyperhomocysteinemia (Hhe induced by homocysteine thiolactone (HcyT. Methods: Fifteen male Wistar rats were divided into three groups according to their treatment. Animals received water and food ad libitum and an intragastric probe was used to administer water for 60 days (groups: CB6, HcyT, and HB6. On the 30th day of treatment, two groups were supplemented with VB6 in the drinking water (groups: CB6 and HB6. After 60 days of treatment, homocysteine (Hcy, cysteine, and hydrogen peroxide concentration, nuclear factor (erythroid-derived 2-like 2 (NRF2 and glutathione S-transferase (GST immunocontent, and superoxide dismutase (SOD, catalase (CAT, and GST activities were measured. Results: The HcyT group showed an increase in Hcy concentration (62% in relation to the CB6 group. Additionally, GST immunocontent was enhanced (51% in the HB6 group compared to the HcyT group. Also, SOD activity was lower (17% in the HB6 group compared to the CB6 group, and CAT activity was higher in the HcyT group (53% compared to the CB6 group. Ejection fraction (EF was improved in the HB6 group compared to the HcyT group. E/A ratio was enhanced in the HB6 group compared to the CB6 group. Correlations were found between CAT activity with myocardial performance index (MPI (r = 0.71; P = 0.06 and E/A ratio (r = 0.6; P = 0.01, and between EF and GST activity (r = 0.62; P = 0.02. Conclusions: These findings indicate that isolated VB6 supplementation may lead to the reduction of Hcy concentration and promotes additional benefits to oxidative stress and heart function parameters.   Keywords: Homocysteine; oxidative stress; vitamin B6.

  11. The Role of Stress-Effected Subgrain Size Distribution in Anelastic Recovery: An Experimental Study on Polycrystalline Ice-Ih

    Science.gov (United States)

    Caswell, T. E.; Goldsby, D. L.; Cooper, R. F.; Prior, D. J.

    2013-12-01

    Anelasticity, or time-dependent and recoverable strain, is the source of attenuation at seismic and sub-seismic frequencies, yet the processes governing anelastic recovery are poorly resolved. Numerous experimental studies [e.g., 1-3] have demonstrated that anelasticity occurs via diffusion-effected relaxation along grain boundaries, which leads to a significant grain size sensitivity. Similar studies, however, conducted on deformed single crystals [e.g. 4], coarse-grained metals deforming in dislocation creep [e.g., 5] and polycrystalline ice deforming via a dislocation-accommodated mechanism [6] demonstrate the same frequency dependence, consistent with the grain boundary mechanism, but with no sensitivity to grain size. We postulate that it is the deformation-effected distribution of subgrains, which possesses unique diffusive properties relative to a defect-free lattice, that dominates attenuation in these situations. To test this idea we are conducting creep and stress-drop experiments on polycrystalline ice-Ih with concurrent high-resolution microstructural analysis conducted via Electron Backscatter Diffraction (EBSD) [7] to characterize the relationship between subgrain size distribution and diffusion-effected anelasticity. Our experiments establish the subgrain size distribution in steady-state creep of fine-grained ice-1h at compressional stresses between 0.1-4 MPa, which for the grain sizes and temperatures of our experiments places the rheology squarely within the regime of grain boundary sliding that is accommodated by basal dislocation slip [8]. We then explore the dynamics of the established microstructure, which includes subgrain formation [cf. 9], via stress-drop experiments [e.g. 10]. Experiments of this type allow the characterization of microstructural 'hardness,' i.e., the viscosity of the polycrystalline solid as effected by finite strain, from which we can discern the diffusive kinetics of subgrain boundaries [11, 12]. We are currently

  12. An in vivo Experimental System to Study Sugar Phloem Unloading in Ripening Grape Berries During Water Deficiency Stress

    Science.gov (United States)

    WANG, ZHEN‐PING; DELOIRE, ALAIN; CARBONNEAU, ALAIN; FEDERSPIEL, BRIGITTE; LOPEZ, FRANÇOIS

    2003-01-01

    An in vivo experimental system—called the ‘berry‐cup’ technique—was developed to study sugar phloem unloading and the accumulation of sugar in ripening grape berries. The berry‐cup system consists of a single peeled grape berry immersed in a buffer solution in a cup prepared from a polypropylene syringe. A small cross‐incision (2 mm in length) is made on the stylar remnant of a berry during its ripening phase, the skin of the berry then being easily peeled off, exposing the dorsal vascular bundles without damaging either these or the pulp tissue of the berry. The sites of sugar phloem unloading are thus made directly accessible and may be regulated by the buffer solution. In addition, the unloaded photoassimilates are easily transported into the buffer solution in the berry‐cup. With the berry‐cup technique, it takes 60 min to purge the sugar already present in the apoplast, after which the amount of sugar in the buffer solution is a direct measure of the sugar unloading from the grape berry phloem. The optimum times for sampling were 20 or 30 min, depending on the type of experiment. Sugar phloem unloading was significantly inhibited by the inclusion of either 7·5 mm NaF or 2·5 mm PCMB in the buffer solution. This study indicates that sugar phloem unloading in ripening grape berries is via the apoplastic network and that the process requires the input of energy. The system was shown to be an appropriate experimental system with which to study sugar phloem unloading in ripening grape berries, and was applied successfully to the study of berry sugar unloaded from grapevines subjected to water stress. The results showed that water deficiency inhibits sugar unloading in grape berries. PMID:12907466

  13. Jaw-motor effects of experimental jaw-muscle pain and stress in patients with deep bite and matched control subjects

    DEFF Research Database (Denmark)

    Sonnesen, Liselotte; Svensson, Peter

    2013-01-01

    OBJECTIVE: The effect of experimental jaw-muscle pain and stress on masticatory muscle activity in TMD-patients has been discussed. Furthermore, associations between TMD and deep bite patients have been studied. Accordingly in the present study, comparison of EMG responses at rest, maximal...

  14. The effects of experimentally induced rumination, positive reappraisal, acceptance, and distancing when thinking about a stressful event on affect states in adolescents

    NARCIS (Netherlands)

    Rood, L.; Roelofs, J.; Bögels, S.M.; Arntz, A.

    2012-01-01

    The current study compares the effects of experimentally induced rumination, positive reappraisal, distancing, and acceptance on affect states in adolescents aged 13-18. Participants (N = 160) were instructed to think about a recent stressful event. Next, they received specific instructions on how

  15. 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.

  16. An Experimental Study of Mortars with Recycled Ceramic Aggregates: Deduction and Prediction of the Stress-Strain

    Directory of Open Access Journals (Sweden)

    Francisca Guadalupe Cabrera-Covarrubias

    2016-12-01

    Full Text Available The difficult current environmental situation, caused by construction industry residues containing ceramic materials, could be improved by using these materials as recycled aggregates in mortars, with their processing causing a reduction in their use in landfill, contributing to recycling and also minimizing the consumption of virgin materials. Although some research is currently being carried out into recycled mortars, little is known about their stress-strain (σ-ε; therefore, this work will provide the experimental results obtained from recycled mortars with recycled ceramic aggregates (with contents of 0%, 10%, 20%, 30%, 50% and 100%, such as the density and compression strength, as well as the σ-ε curves representative of their behavior. The values obtained from the analytical process of the results in order to finally obtain, through numerical analysis, the equations to predict their behavior (related to their recycled content are those of: σ (elastic ranges and failure maximum, ε (elastic ranges and failure maximum, and Resilience and Toughness. At the end of the investigation, it is established that mortars with recycled ceramic aggregate contents of up to 20% could be assimilated just like mortars with the usual aggregates, and the obtained prediction equations could be used in cases of similar applications.

  17. Effects of helium-neon laser on levels of stress protein and arthritic histopathology in experimental osteoarthritis.

    Science.gov (United States)

    Lin, Yueh-Shuang; Huang, Mao-Hsiung; Chai, Chee-Yin; Yang, Rei-Cheng

    2004-10-01

    To investigate the effect of low-power laser therapy on levels of stress proteins (SPs) in experimental arthritis and their relation to the bioeffects on arthritic cartilage repair. A total of 42 rats with similar degrees of induced arthritis evaluated by means of bone scan were divided randomly into two groups. In the treated group, 21 rats received helium-neon laser treatment; in the control group, 21 rats received sham laser treatment. The changes in chondrocytes of SPs were measured by electrophoresis of proteins extracted from chondrocytes of arthritic cartilage at various time periods. The histopathologic changes and the presence of SP of arthritic cartilage were identified by hematoxylin and eosin stain and by immunostains of SP72 antibody individually from frozen sections of arthritic cartilage. SP density increased markedly in rats after laser treatment and was closely related to the repair of arthritic cartilage. Furthermore, the pathohistology of arthritic cartilage improved significantly with the decline of SP levels in the follow-up period. Helium-neon (632 nm) low-power laser can enhance SP production in arthritic chondrocytes. The extragenic production of SP is well correlated with the therapeutic effect of low-power laser in preserving chondrocytes and the repair of arthritic cartilage in rats.

  18. The Involvement of a Polyphenol-Rich Extract of Black Chokeberry in Oxidative Stress on Experimental Arterial Hypertension

    Directory of Open Access Journals (Sweden)

    Manuela Ciocoiu

    2013-01-01

    Full Text Available The aim of this study is to characterize the content of Aronia melanocarpa Elliott (black chokeberry extract and also to estimate the influence of polyphenolic compounds contained in chokeberries on oxidative stress, on an L-NAME-induced experimental model of arterial hypertension. The rat blood pressure values were recorded using a CODA Noninvasive Blood Pressure System. HPLC/DAD coupled with ElectroSpray Ionization-Mass Spectrometry allowed identification of five phenolic compounds in berries ethanolic extract as follows: chlorogenic acid, kuromanin, rutin, hyperoside, and quercetin. The serous activity of glutathione-peroxidase (GSH-Px has significantly lower values in the hypertensive (AHT group as compared to the group protected by polyphenols (AHT + P. The total antioxidant capacity (TAC values are lower in the AHT group and they are significantly higher in the AHT + P group. All the measured blood pressure components revealed a biostatistically significant blood pressure drop between the AHT group and the AHT + P group. The results reveal the normalization of the reduced glutathion (GSH concentration as well as a considerable reduction in the malondialdehyde (MDA serum concentration in the AHT + P group. Ethanolic extract of black chokeberry fruits not only has a potential value as a prophylactic agent but also may function as a nutritional supplement in the management of arterial hypertension.

  19. Experimental study of the solid-liquid interface in a yield-stress fluid flow upstream of a step

    Science.gov (United States)

    Luu, Li-Hua; Philippe, Pierre; Chambon, Guillaume

    2015-01-01

    We present an experimental study investigating the transition zone between a liquid-like unyielded region and a solid-like yielded region in a yield-stress fluid. The configuration consists of a rectangular closed-channel flow disturbed by the presence of a step. Upstream of the step, a solid-liquid interface between a dead zone and a flow zone appears. In this study, we use a model fluid, namely polymer micro-gel Carbopol, which exhibits Herschel-Bulkley viscoplastic rheology. Exploiting the fluid transparency, the flow is monitored by particle image velocimetry using an internal visualization technique. The main outcome of this study is to show that, except in a thin transition layer close to the solid-liquid interface, the flow behaves as an apparent Poiseuille flow with an apparent slip condition at the base. The slip frontier is found to be almost independent of the flow rate while the corresponding slip velocity increases with the flow rate.

  20. Experimental study of the solid-liquid interface in a yield-stress fluid flow upstream of a step.

    Science.gov (United States)

    Luu, Li-Hua; Philippe, Pierre; Chambon, Guillaume

    2015-01-01

    We present an experimental study investigating the transition zone between a liquid-like unyielded region and a solid-like yielded region in a yield-stress fluid. The configuration consists of a rectangular closed-channel flow disturbed by the presence of a step. Upstream of the step, a solid-liquid interface between a dead zone and a flow zone appears. In this study, we use a model fluid, namely polymer micro-gel Carbopol, which exhibits Herschel-Bulkley viscoplastic rheology. Exploiting the fluid transparency, the flow is monitored by particle image velocimetry using an internal visualization technique. The main outcome of this study is to show that, except in a thin transition layer close to the solid-liquid interface, the flow behaves as an apparent Poiseuille flow with an apparent slip condition at the base. The slip frontier is found to be almost independent of the flow rate while the corresponding slip velocity increases with the flow rate.

  1. Deep sequencing analyses expands the Pseudomonas aeruginosa AmpR regulon to include small RNA-mediated regulation of iron acquisition, heat shock and oxidative stress response

    Science.gov (United States)

    Balasubramanian, Deepak; Kumari, Hansi; Jaric, Melita; Fernandez, Mitch; Turner, Keith H.; Dove, Simon L.; Narasimhan, Giri; Lory, Stephen; Mathee, Kalai

    2014-01-01

    Pathogenicity of Pseudomonas aeruginosa, a major cause of many acute and chronic human infections, is determined by tightly regulated expression of multiple virulence factors. Quorum sensing (QS) controls expression of many of these pathogenic determinants. Previous microarray studies have shown that the AmpC β-lactamase regulator AmpR, a member of the LysR family of transcription factors, also controls non-β-lactam resistance and multiple virulence mechanisms. Using RNA-Seq and complementary assays, this study further expands the AmpR regulon to include diverse processes such as oxidative stress, heat shock and iron uptake. Importantly, AmpR affects many of these phenotypes, in part, by regulating expression of non-coding RNAs such as rgP32, asRgsA, asPrrF1 and rgRsmZ. AmpR positively regulates expression of the major QS regulators LasR, RhlR and MvfR, and genes of the Pseudomonas quinolone system. Chromatin immunoprecipitation (ChIP)-Seq and ChIP–quantitative real-time polymerase chain reaction studies show that AmpR binds to the ampC promoter both in the absence and presence of β-lactams. In addition, AmpR directly binds the lasR promoter, encoding the QS master regulator. Comparison of the AmpR-binding sequences from the transcriptome and ChIP-Seq analyses identified an AT-rich consensus-binding motif. This study further attests to the role of AmpR in regulating virulence and physiological processes in P. aeruginosa. PMID:24157832

  2. Impact of applied progressive deep muscle relaxation training on the level of depression, anxiety and stress among prostate cancer patients: a quasi-experimental study.

    Science.gov (United States)

    Isa, Mohamad Rodi; Moy, Foong Ming; Abdul Razack, Azad Hassan; Zainuddin, Zulkifli Md; Zainal, Nor Zuraida

    2013-01-01

    The aim of this study was to determine the impact of applied progressive muscle relaxation training on the levels of depression, anxiety and stress among prostate cancer patients. A quasi-experimental study was conducted at the University Malaya Medical Centre (UMMC) and Universiti Kebangsaan Malaysia Medical Centre (UKMMC) over six months. Prostate cancer patients from UMMC received the intervention and patients from UKMMC were taken as controls. The level of depression, anxiety and stress were measured using Depression, Anxiety Stress Scales - 21 (DASS-21). A total of 77 patients from the UMMC and 78 patients from the UKMMC participated. At the end of the study, 90.9% and 87.2% of patients from the UMMC and UKMMC groups completed the study respectively. There were significant improvements in anxiety (prelaxation therapy among prostate cancer patients as a coping strategy to improve their anxiety and stress.

  3. Experimental research of residual stresses kinetics in the hardened hollow cylindrical specimens of D16T alloy at the axial tension under the creep conditions

    Directory of Open Access Journals (Sweden)

    Vladimir P. Radchenko

    2016-06-01

    Full Text Available We study experimentally the effect of the axial tension load on the residual stresses relaxation in the surface-hardened hollow cylindrical specimens of D16T aluminium alloy at a temperature of 125 ∘C. The surface is hardened by the air shot-peening. We describe the testing machine and the routine of experiment. The experimental curves of hardened specimens creep under the axial loads 353, 385, 406.2, 420 MPa and test duration of 100–160 hours are obtained. The axial and circumferential residual stresses after the hardening and the creep at the given temperature and load conditions are constructed by the method of circles and strips. The significant qualitative and quantitative changes of residual stresses take place under the tension load σ¯ in comparison with the thermal exposure (heat exposal with no load. The relaxation of residual stresses is essentially independent of the thermal exposure. In contrast, the loading leads to the significant residual stresses relaxation and to the changes in the distribution type. The axial and circumferential residual stresses evolve from the compressive to the tension with the increase of the axial tension load. Also the depth of residual stresses location changes with the increase of the axial tension load from the 600 microns in the original state after the air shot-peening to the 250–300 microns after the creep under the given loading. It is very important for the engineering applications to take into account the described behaviours of the residual stresses in the hardened specimens of D16T alloy when predicting the characteristics of endurance of the surface-hardened details operate under the elevated temperatures.

  4. Finite element analyses of wood laminated composite poles

    Science.gov (United States)

    Cheng Piao; Todd F. Shupe; R.C. Tang; Chung Y. Hse

    2005-01-01

    Finite element analyses using ANSYS were conducted on orthotropic, polygonal, wood laminated composite poles subjected to a body force and a concentrated load at the free end. Deflections and stress distributions of small-scale and full-size composite poles were analyzed and compared to the results obtained in an experimental study. The predicted deflection for both...

  5. Medical ozone therapy reduces oxidative stress and intestinal damage in an experimental model of necrotizing enterocolitis in neonatal rats.

    Science.gov (United States)

    Guven, Ahmet; Gundogdu, Gokhan; Vurucu, Sabahattin; Uysal, Bulent; Oztas, Emin; Ozturk, Haluk; Korkmaz, Ahmet

    2009-09-01

    Necrotizing enterocolitis (NEC) remains a major cause of morbidity and death in neonates. Evidence suggests that an imbalance between activated proinflammatory response with inadequate antiinflammatory protection results in NEC. Ozone has been proposed as an antioxidant enzyme activator, immunomodulator, and cellular metabolic activator. Therefore, this study was designed to investigate whether medical ozone therapy is effective on neonatal rat model of NEC. Thirty-eight newborn Sprague-Dawley pups were randomly divided into 3 groups of NEC, NEC + ozone, and control (left to breast feed). Necrotizing enterocolitis was induced by enteral formula feeding and exposure to 100% carbon dioxide inhalation for 10 minutes after +4 degrees C cold exposures for 5 minutes and 97% oxygen for 5 minutes 2 times daily. The NEC + ozone group received 0.7 mg/kg per day ozone/oxygen mixture intraperitoneally for a total of 3 days after first day of NEC procedure. The pups were killed at fourth day, and their intestinal tissues were harvested for biochemical and histopathologic analysis. Blood sample from pups were also obtained. The mortality rate and the weight loss were significantly higher in NEC group than control and treatment groups. Oxidative stress markers (malondialdehyde and protein carbonyl content) significantly increased and antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase) were significantly decreased in NEC group. All these biochemical changes were ameliorated in NEC + ozone group. Nitrate plus nitrite levels and serum tumor necrosis factor alpha were elevated in NEC group and reduced in treatment group. In addition, histopathologic injury score of NEC group was significantly higher than NEC + ozone group. Ozone treatment significantly reduced the severity of NEC by modulating antioxidative defense and antiinflammatory protection in our experimental animal model.

  6. How Psychological Stress Affects Emotional Prosody

    Science.gov (United States)

    Paulmann, Silke; Furnes, Desire; Bøkenes, Anne Ming; Cozzolino, Philip J.

    2016-01-01

    We explored how experimentally induced psychological stress affects the production and recognition of vocal emotions. In Study 1a, we demonstrate that sentences spoken by stressed speakers are judged by naïve listeners as sounding more stressed than sentences uttered by non-stressed speakers. In Study 1b, negative emotions produced by stressed speakers are generally less well recognized than the same emotions produced by non-stressed speakers. Multiple mediation analyses suggest this poorer recognition of negative stimuli was due to a mismatch between the variation of volume voiced by speakers and the range of volume expected by listeners. Together, this suggests that the stress level of the speaker affects judgments made by the receiver. In Study 2, we demonstrate that participants who were induced with a feeling of stress before carrying out an emotional prosody recognition task performed worse than non-stressed participants. Overall, findings suggest detrimental effects of induced stress on interpersonal sensitivity. PMID:27802287

  7. How Psychological Stress Affects Emotional Prosody.

    Directory of Open Access Journals (Sweden)

    Silke Paulmann

    Full Text Available We explored how experimentally induced psychological stress affects the production and recognition of vocal emotions. In Study 1a, we demonstrate that sentences spoken by stressed speakers are judged by naïve listeners as sounding more stressed than sentences uttered by non-stressed speakers. In Study 1b, negative emotions produced by stressed speakers are generally less well recognized than the same emotions produced by non-stressed speakers. Multiple mediation analyses suggest this poorer recognition of negative stimuli was due to a mismatch between the variation of volume voiced by speakers and the range of volume expected by listeners. Together, this suggests that the stress level of the speaker affects judgments made by the receiver. In Study 2, we demonstrate that participants who were induced with a feeling of stress before carrying out an emotional prosody recognition task performed worse than non-stressed participants. Overall, findings suggest detrimental effects of induced stress on interpersonal sensitivity.

  8. Effect of melatonin on myocardial oxidative stress induced by experimental obstructive jaundice Efecto de la melatonina en el estrés oxidativo del miocardio en un modelo experimental de obstrucción biliar

    Directory of Open Access Journals (Sweden)

    A. Cruz

    2009-07-01

    Full Text Available Objective: melatonin has been demonstrated to have active antioxidant properties in different tissues during experimental cholestasis. The aim of this research was to study myocardial oxidative stress on obstructive jaundice, and to analyze the effect of melatonin on myocardial oxidative lesions. Material and methods: we achieved cholestasis by ligature and sectioning of the main bile duct. Melatonin was administered intraperitoneally (500 µg/kg/day. We measured malondialdehyde (MDA, reduced glutathione (GSH, catalase (CAT, superoxide dismutase (SOD and glutathione peroxydase (GPx antioxidant enzyme levels in the heart tissue. Results: obstructive cholestasis increased MDA and decreased GSH as well as all antioxidant enzymes. Melatonin administration significantly decreased MDA values, and increased GSH and antioxidant enzymes on the icteric animal myocardium. Conclusions: melatonin treatment prevents oxidative stress in the cardiac tissue as induced by experimental cholestasis.

  9. The Impact of Experimental Hypoxia and Subsequent Normoxia on the Content of Some Ions and Markers of Physiological Stress-adaptation in Gastropod Species Lymnaea stagnalis

    Directory of Open Access Journals (Sweden)

    Lubyaga J.А.

    2014-12-01

    Full Text Available The purpose of this study was to evaluate the influence of hypoxia and subsequent normoxiaon the maintenance of respiratory pigment hemocyanin, total protein, lactate and some ions (Na +, K +, Ca2+, NH4+, Mg2+ in the mantle liquid in palaearctic gastropod species Lymnaea stagnalis. It was shown that short-term experimental hypoxia leads to the activation of the physiological mechanisms of stress adaptation in widespread Palaearctic eurybiotic gastropod species and does not lead to the activation of the stress-resistance mechanisms on the biochemical and molecular levels.

  10. An Experimental Investigation of Stresses in a Steel Model of an Overloaded Breech Ring by Means of Photoelastic Coating Technique

    Science.gov (United States)

    1980-08-01

    following the same law of yielding. The shape of the stress strain 4 curve is represented by a parameter in the Ramberg - Osgood equation. It is possible...becomes ^ Ramberg , W. and Osgood , W. R., "Description of Stress-Strain Curves by Three Parameters," NACA TN 902, 1943. ^Mesnager, M., "Sur la...34 to be presented at the International Conference on Reliability Stress Analysis and Failure Presentation, ASME, San Francisco, August 1980. 4. Ramberg

  11. Experimental determination of the micro-scale strength and stress-strain relation of an epoxy resin

    DEFF Research Database (Denmark)

    Zike, Sanita; Sørensen, Bent F.; Mikkelsen, Lars Pilgaard

    2016-01-01

    An approach is developed for determining the stress-strain law and a failure stress appropriate for micro-mechanical models of polymer materials. Double cantilever beam test specimens, made of an epoxy polymer with notches having finite root radius, were subjected to pure bending moments in an en......An approach is developed for determining the stress-strain law and a failure stress appropriate for micro-mechanical models of polymer materials. Double cantilever beam test specimens, made of an epoxy polymer with notches having finite root radius, were subjected to pure bending moments...

  12. A Quasi-Experimental Study on Using Short Stories: Statistical and Inferential Analyses on the Non-English Major University Students' Speaking and Writing Achievements

    Science.gov (United States)

    Iman, Jaya Nur

    2017-01-01

    This research was conducted to find out whether or not using short stories significantly improve the speaking and writing achievements. A quasi-experimental study of non-equivalent pretest-posttest control group design or comparison group design was used in this research. The population of this research was the all first semester undergraduate…

  13. Oxidative macromolecular alterations in the rat central nervous system in response to experimentally co-induced chlorpyrifos and cold stress: a comparative assessment in aging rats.

    Science.gov (United States)

    Basha, P Mahaboob; Poojary, Annappa

    2012-02-01

    Reactive oxygen species are generated as a result of a number of physiological and pathological processes which can promote multiple forms of oxidative damage including protein oxidation, and thereby influence the function of a diverse array of cellular processes. In our previous study we have reported that co-exposure to chlorpyrifos and cold stress in aging rats markedly influence the toxic outcome as a result of oxidative stress. In the present study, key neurochemical/enzymes were measured in order to evaluate the macromolecular alterations in response to experimentally co-induced chlorpyrifos and cold stress (15 and 20°C) either concurrently or individually in vivo for 48 h in discrete regions of brain and spinal cord of different age group rats. CPF and cold stress exposure either individually or in combination substantially increased the activity/levels of protein carbonyls, AST, ALT and decreased protein thiols, DNA, RNA and total proteins in discrete regions of CNS. Overall, the effects of co-exposure were appreciably different from either of the exposures. However, synergistic-action of CPF and cold stress at 15°C showed higher dyshomeostasis in comparison with CPF and cold stress alone and together at 20°C indicating the extent of oxidative macromolecular damage in discrete regions of brain and spinal cord. Furthermore, the present study demonstrates that macromolecular oxidative damage is highly pronounced in neonates and juveniles than the young adults.

  14. "Learn Young, Learn Fair", a Stress Management Program for Fifth and Sixth Graders: Longitudinal Results from an Experimental Study

    Science.gov (United States)

    Kraag, Gerda; Van Breukelen, Gerard J. P.; Kok, Gerjo; Hosman, Clemens

    2009-01-01

    Background: This study examined the effects of a universal stress management program (Learn Young, Learn Fair) on stress, coping, anxiety and depression in fifth and sixth grade children. Methods: Fifty-two schools (1467 children) participated in a clustered randomized controlled trial. Data was collected in the fall of 2002, the spring of 2003,…

  15. 'Learn Young, Learn Fair', a stress management program for fifth and sixth graders: longitudinal results from an experimental study

    NARCIS (Netherlands)

    Kraag, G.C; Breukelen, G.J.P. van; Kok, G.J.; Hosman, C.M.H.

    2009-01-01

    Background - This study examined the effects of a universal stress management program (Learn Young, Learn Fair) on stress, coping, anxiety and depression in fifth and sixth grade children. Methods - Fiftytwo schools (1467 children) participated in a clustered randomized controlled trial. Data was

  16. Experimental Investigation on the Fatigue Life of Ti-6Al-4V Treated by Vibratory Stress Relief

    Directory of Open Access Journals (Sweden)

    Han-Jun Gao

    2017-05-01

    Full Text Available Vibratory stress relief (VSR is a highly efficient and low-energy consumption method to relieve and homogenize residual stresses in materials. Thus, the effect of VSR on the fatigue life should be determined. Standard fatigue specimens are fabricated to investigate the fatigue life of Ti-6Al-4V titanium alloy treated by VSR. The dynamic stresses generated under different VSR amplitudes are measured, and then the relationship between the dynamic stress and vibration amplitude is obtained. Different specimen groups are subjected to VSRs with different amplitudes and annealing treatment with typical process parameters. Residual stresses are measured to evaluate the stress relieving effects. Finally, the fatigue behavior under different states is determined by uniaxial tension–compression fatigue experiments. Results show that VSR and annealing treatment have negative effects on the fatigue life of Ti-6Al-4V. The fatigue life is decreased with the increase in VSR amplitude. When the VSR amplitude is less than 0.1 mm, the decrease in fatigue limit is less than 2%. Compared with specimens without VSR or annealing treatment, the fatigue limit of the specimens treated by VSR with 0.2 mm amplitude and annealing treatment decreases by 10.60% and 8.52%, respectively. Although the stress relieving effect is better, high amplitude VSR will lead to the decrease of Ti-6Al-4V fatigue life due to the defects generated during vibration. Low amplitude VSR can effectively relieve the stress with little decrease in fatigue life.

  17. [Experimental evaluation of combined effects caused by stress and metals (cadmium and aluminium) in reproductivity of male rats].

    Science.gov (United States)

    Makutina, V A; Balezin, S L; Slyshkina, T V; Pashnina, I A; Likhacheva, E I

    2014-01-01

    To investigate combined effects of stress and metal (aluminium, cadmium) on reproductivity, male rats twice per week received intraperitoneal injections of aluminium (3.8 mg Al3+ per kg of body weight) or cadmium (0.3 mg Cd2+ per kg of body weight) and were subjected to stress via short-term immobilization during spermatogenic cycle (54 +/- 3 days). Findings are cumulation of both cadmium and aluminium in genitals and brain, increasing under stress. When acting separately to the laboratory animals, the three factors (aluminium/cadmium/stress) increase serum corticosterone level, change testosterone level, increase number of aberrant mitoses of spermatogenic epithelium cells, increased sperm count with fragmented DNA, lower percentage of the impregnated females. If the exposure combined with stress, spermatogenesis disorders are more marked, and preimplantation death rate of intact females' offspirngs becomes statistically significant.

  18. Stress and consumption of alcohol in humans with a Type 1 family history of alcoholism in an experimental laboratory setting.

    Science.gov (United States)

    Gordh, Anna H V Söderpalm; Brkic, Sejla; Söderpalm, Bo

    2011-10-01

    This paper investigates how stress interacts with alcohol consumption in subjects with a family history of alcoholism. One mechanism for increases in alcohol intake may be that stress alters the subjective effects produced by the drug. 58 healthy volunteers, divided into two groups of family history positive (FHP) and two groups of family history negative (FHN) participated in two laboratory sessions, in which they performed in one out of two sessions a stress task. Then subjects were allowed to choose up to six additional drinks of ethanol or placebo depending on which session they were randomly assigned to start with. It was found that FHP subjects increased their consumption of alcohol after stress. It is possible that both stress and alcohol specifically exaggerate the feelings of the reward in the FHP individuals in such way that it may increase the likelihood of consuming more alcohol. Copyright © 2011. Published by Elsevier Inc.

  19. A QUASI-EXPERIMENTAL STUDY ON USING SHORT STORIES: STATISTICAL AND INFERENTIAL ANALYSES ON THE NON-ENGLISH MAJOR UNIVERSITY STUDENTS’ SPEAKING AND WRITING ACHIEVEMENTS

    OpenAIRE

    Jaya Nur Iman

    2017-01-01

    This research was conducted to find out whether or not using short stories significantly improve the speaking and writing achievements. A quasi-experimental study of non-equivalent pretest-posttest control group design or comparison group design was used in this research. The population of this research was the all first semester undergraduate students of urban and regional planning study program of Indo Global Mandiri University. Forty students were selected as the sample by using purposive ...

  20. Evolution of the stress fields in the Zagros Foreland Folded Belt using focal mechanisms and kinematic analyses: the case of the Fars salient, Iran

    Science.gov (United States)

    Sarkarinejad, Khalil; Zafarmand, Bahareh; Oveisi, Behnam

    2017-07-01

    The NW-SE trending Zagros orogenic belt was initiated during the convergence of the Afro-Arabian continent and the Iranian microcontinent in the Late Cretaceous. Ongoing convergence is confirmed by intense seismicity related to compressional stresses collision-related in the Zagros orogenic belt by reactivation of an early extensional faulting to latter compressional segmented strike-slip and dip-slip faulting. These activities are strongly related either to the deep-seated basement fault activities (deep-seated earthquakes) underlies the sedimentary cover or gently dipping shallow-seated décollement horizon of the rheological weak rocks of the infra-Cambrian Hormuz salt. The compressional stress regimes in the different units play an important role in controlling the stress conditions between the different units within the sedimentary cover and basement. A significant set of nearly N-S trending right-lateral strike-slip faults exists throughout the study area in the Fars area in the Zagros Foreland Folded Belt. Fault-slip and focal mechanism data were analyzed using the stress inversion method to reconstruct the paleo and recent stress conditions. The results suggest that the current direction of maximum principal stress averages N19°E, with N38°E that for the past from Cretaceous to Tertiary (although a few sites on the Kar-e-Bass fault yield a different direction). The results are consistent with the collision of the Afro-Arabian continent and the Iranian microcontinent. The difference between the current and paleo-stress directions indicates an anticlockwise rotation in the maximum principle stress direction over time. This difference resulted from changes in the continental convergence path, but was also influenced by the local structural evolution, including the lateral propagation of folds and the presence of several local décollement horizons that facilitated decoupling of the deformation between the basement and the sedimentary cover. The obliquity of

  1. Experimental and in silico modelling analyses of the gene expression pathway for recombinant antibody and by-product production in NS0 cell lines.

    Directory of Open Access Journals (Sweden)

    Emma J Mead

    Full Text Available Monoclonal antibodies are commercially important, high value biotherapeutic drugs used in the treatment of a variety of diseases. These complex molecules consist of two heavy chain and two light chain polypeptides covalently linked by disulphide bonds. They are usually expressed as recombinant proteins from cultured mammalian cells, which are capable of correctly modifying, folding and assembling the polypeptide chains into the native quaternary structure. Such recombinant cell lines often vary in the amounts of product produced and in the heterogeneity of the secreted products. The biological mechanisms of this variation are not fully defined. Here we have utilised experimental and modelling strategies to characterise and define the biology underpinning product heterogeneity in cell lines exhibiting varying antibody expression levels, and then experimentally validated these models. In undertaking these studies we applied and validated biochemical (rate-constant based and engineering (nonlinear models of antibody expression to experimental data from four NS0 cell lines with different IgG4 secretion rates. The models predict that export of the full antibody and its fragments are intrinsically linked, and cannot therefore be manipulated individually at the level of the secretory machinery. Instead, the models highlight strategies for the manipulation at the precursor species level to increase recombinant protein yields in both high and low producing cell lines. The models also highlight cell line specific limitations in the antibody expression pathway.

  2. Experimental evaluation of water vapour cross-sensitivity for accurate eddy covariance measurement of CO2 flux using open-path CO2/H2O gas analysers

    Directory of Open Access Journals (Sweden)

    Fumiyoshi Kondo

    2014-10-01

    Full Text Available Non-dispersive infrared CO2/H2O gas analysers produce erroneous CO2 outputs when CO2 is measured in humid air, unless a correction for water vapour cross-sensitivity is applied. Spectroscopic cross-sensitivities arising from direct absorption interference and from the pressure broadening effect are significant in CO2 flux measurements by the eddy covariance technique using open-path gas analysers over the ocean, as opposed to land-surface measurements, where CO2 fluxes are orders of magnitude larger. In this study, a widely used analyser with manufacturer-determined correction coefficients for both cross-sensitivities was tested by laboratory experiments. Our results showed that the correction coefficient for direct absorption interference was not optimised to calculate CO2 flux accurately, and that the correction coefficient for the pressure broadening caused overestimation of the CO2 mixing ratio flux in the same direction as the water vapour flux. Overestimations of open-path eddy covariance measurements of upward CO2 fluxes in previous ocean observations probably resulted from inaccuracies in both of these correction coefficients. We also found that slight changes in spectroscopic cross-sensitivities due to contamination of the analyser's optical windows by sea salt caused a low bias in CO2 outputs with increasing H2O; however, this contamination effect was not always observed in repeated tests under different contamination conditions. We suggest that previously proposed methods for correcting the effect of optical window contamination is of limited value and that measurement of small CO2 fluxes by the open-path eddy covariance technique over the ocean should be performed after confirming the spectroscopic cross-sensitivity and ensuring that the optical windows are as clean as possible.

  3. Comparative radiographic and resonance frequency analyses of the peri-implant tissue after dental implants placement using flap and flapless techniques: An experimental study on domestic pigs

    OpenAIRE

    Vlahović Zoran; Mihailović Branko; Lazić Zoran; Golubović Mileta

    2013-01-01

    Background/Aim. Flapless implant surgery has become very important issue during recent years, mostly thanks to computerization of dentistry and software planning of dental implants placements. The aim of this study was to compare flap and flapless surgical techniques for implant placement through radiographic and radiofrequency analyses. Methods. The experiment was made in five domestic pigs. Nine weeks following domestic pigs teeth extraction, implants were placed, on the right side us...

  4. Stress distribution and micromotion analyses of immediately loaded implants of varying lengths in the mandible and fibular bone grafts: a three-dimensional finite element analysis.

    Science.gov (United States)

    Wu, Jacqueline Chia-Hsuan; Chen, Chen-Sheng; Yip, Shing-Wai; Hsu, Ming-Lun

    2012-01-01

    The aim of the present study was to compare the biomechanical effects of different lengths of implants in an immediate loading condition in mandibular and fibular bone. Three-dimensional (3D) nonlinear finite element analysis (FEA) was used to examine the complex irregular structures. The variables of this research were the two different bone types (mandible and fibula) and three different implant lengths. Simplified half models were constructed for 3D FEA. Three different implant lengths (6 mm, 10 mm, and 15 mm) were inserted into the mandibular and fibular bone models, which were made to simulate immediate implant loading conditions. A load of 125 N was applied to the center of the suprastructure at a 45-degree angle relative to the long axis of the implant, and the resultant maximum von Mises equivalent (EQV) stresses, stress distribution, strain energy, and micromotion were measured. In the mandible, the maximum EQV stresses were 115.636 MPa, 155.943 MPa, and 157.105 MPa with the 6-mm, 10-mm, and 15-mm implants, respectively. The mean EQV stresses were 64.145 MPa, 77.925 MPa, and 78.500 MPa, respectively. In the fibula, the maximum EQV stresses were 174.04 MPa, 157.456 MPa, and 144.353 MPa with the 6-mm, 10-mm, and 15-mm implants, respectively. The mean EQV stresses were 82.329 MPa, 73.526 MPa, and 74.050 MPa, respectively. The micromotion in the fibula models was lower than that seen in the mandible models. EQV stress in the fibular bone was different from that in the mandible. Short implants can be an option for oral rehabilitation in the mandible; however, implants in the fibula should probably have bicortical engagement.

  5. Through-Thickness Residual Stress Profiles in Austenitic Stainless Steel Welds: A Combined Experimental and Prediction Study

    Science.gov (United States)

    Mathew, J.; Moat, R. J.; Paddea, S.; Francis, J. A.; Fitzpatrick, M. E.; Bouchard, P. J.

    2017-10-01

    Economic and safe management of nuclear plant components relies on accurate prediction of welding-induced residual stresses. In this study, the distribution of residual stress through the thickness of austenitic stainless steel welds has been measured using neutron diffraction and the contour method. The measured data are used to validate residual stress profiles predicted by an artificial neural network approach (ANN) as a function of welding heat input and geometry. Maximum tensile stresses with magnitude close to the yield strength of the material were observed near the weld cap in both axial and hoop direction of the welds. Significant scatter of more than 200 MPa was found within the residual stress measurements at the weld center line and are associated with the geometry and welding conditions of individual weld passes. The ANN prediction is developed in an attempt to effectively quantify this phenomenon of `innate scatter' and to learn the non-linear patterns in the weld residual stress profiles. Furthermore, the efficacy of the ANN method for defining through-thickness residual stress profiles in welds for application in structural integrity assessments is evaluated.

  6. Through-Thickness Residual Stress Profiles in Austenitic Stainless Steel Welds: A Combined Experimental and Prediction Study

    Science.gov (United States)

    Mathew, J.; Moat, R. J.; Paddea, S.; Francis, J. A.; Fitzpatrick, M. E.; Bouchard, P. J.

    2017-12-01

    Economic and safe management of nuclear plant components relies on accurate prediction of welding-induced residual stresses. In this study, the distribution of residual stress through the thickness of austenitic stainless steel welds has been measured using neutron diffraction and the contour method. The measured data are used to validate residual stress profiles predicted by an artificial neural network approach (ANN) as a function of welding heat input and geometry. Maximum tensile stresses with magnitude close to the yield strength of the material were observed near the weld cap in both axial and hoop direction of the welds. Significant scatter of more than 200 MPa was found within the residual stress measurements at the weld center line and are associated with the geometry and welding conditions of individual weld passes. The ANN prediction is developed in an attempt to effectively quantify this phenomenon of `innate scatter' and to learn the non-linear patterns in the weld residual stress profiles. Furthermore, the efficacy of the ANN method for defining through-thickness residual stress profiles in welds for application in structural integrity assessments is evaluated.

  7. A QUASI-EXPERIMENTAL STUDY ON USING SHORT STORIES: STATISTICAL AND INFERENTIAL ANALYSES ON THE NON-ENGLISH MAJOR UNIVERSITY STUDENTS’ SPEAKING AND WRITING ACHIEVEMENTS

    Directory of Open Access Journals (Sweden)

    Jaya Nur Iman

    2017-04-01

    Full Text Available This research was conducted to find out whether or not using short stories significantly improve the speaking and writing achievements. A quasi-experimental study of non-equivalent pretest-posttest control group design or comparison group design was used in this research. The population of this research was the all first semester undergraduate students of urban and regional planning study program of Indo Global Mandiri University. Forty students were selected as the sample by using purposive sampling technique in which each group consisted of 20 students, respectively. The treatment was given for 14 meetings. This research was primarily concerned on the quantitative data in the form of the students’ speaking and writing scores. Rubrics were used to measure the students’ speaking and writing achievements. The findings showed that (1 there was a significant improvement in speaking and writing achievements where t-obtained of speaking skill by using rubric was 16.110 (p<0.000 and t-obtained of writing skill by using rubric was 18.291 (p<0.000, (2 there was also a significant mean difference in speaking and writing achievements between the experimental and control groups were 4.533 (p<0.000 and 3.504 (p<0.000, (3 the aspect of speaking and writing skill gave high contribution on the students’ speaking and writing achievements in the experimental group. The highest contribution of speaking skill aspect toward the speaking achievement was fluency. Meanwhile the highest contribution of writing skill aspect toward the writing achievement was vocabulary. Hence, it could be concluded that using short stories significantly improve the students’ speaking and writing achievements.

  8. Evaluation of adaptogenic and anti-stress effects of Ranahamsa Rasayanaya-A Sri Lankan classical Rasayana drug on experimental animals.

    Science.gov (United States)

    Somarathna, K Indrajith W K; Chandola, H M; Ravishankar, B; Pandya, K N; Attanayake, A M P; Ashok, B K

    2010-01-01

    Various types of stress not only harm the mental function, but also cause diseases by weakening body defenses. Rasayana therapy has an advantage over the conventional Kayachikitsa treatment in such conditions, as it is capable of counteracting the stress, promote the adaptogenic abilities of the body, enhance mental endurance, etc. These are the some of parameters for evaluation the rasayana effect of a drug, therefore the same have been studied to assess the rasayana effect of Ranahamsa Rasayanaya (RR). Experimental models such as forced swimming induced hypothermia and stress induced gastric ulcer formation have been carried out befitting on Charles Foster strain albino rats to determine the rasayana effect of RR. Statistically highly significant decrease in forced swimming induced hypothermia and non-significant decrease in gastric ulcer formation were observed in the treatment groups, when compared to the stress control group. These results show the probable adaptogenic and anti-stress activities of the test drug. The study results support the claims made by the Sri Lankan traditional practitioners that, the test drug is a potent rasayana formulation.

  9. The effects of antenatal education on fear of childbirth, maternal self-efficacy and post-traumatic stress disorder (PTSD) symptoms following childbirth: an experimental study.

    Science.gov (United States)

    Gökçe İsbir, Gözde; İnci, Figen; Önal, Hatice; Yıldız, Pelin Dıkmen

    2016-11-01

    Fear of birth and low childbirth self-efficacy is predictive of post-traumatic stress disorder symptoms following childbirth. The efficacy of antenatal education classes on fear of birth and childbirth self-efficacy has been supported; however, the effectiveness of antenatal classes on post-traumatic stress disorder symptoms after childbirth has received relatively little research attention. This study examined the effects of antenatal education on fear of childbirth, maternal self-efficacy and post-traumatic stress disorder symptoms following childbirth. Quasi-experimental study. The study was conducted in a city located in the Middle Anatolia region of Turkey and data were collected between December 2013 and May 2015. Two groups of women were compared-an antenatal education intervention group (n=44), and a routine prenatal care control group (n=46). The Wijma Delivery Expectancy/Experience Questionnaire, Version A and B, Childbirth Self-efficacy Inventory and Impact of Event Scale-Revised was used to assess fear of childbirth, maternal self-efficacy and PTSD symptoms following childbirth. Compared to the control group, women who attended antenatal education had greater childbirth self-efficacy, greater perceived support and control in birth, and less fear of birth and post-traumatic stress disorder symptoms following childbirth (all comparisons, ppost-traumatic stress disorder symptoms after childbirth. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. A combined experimental and finite element approach to analyse the fretting mechanism of the head-stem taper junction in total hip replacement.

    Science.gov (United States)

    Bitter, Thom; Khan, Imran; Marriott, Tim; Lovelady, Elaine; Verdonschot, Nico; Janssen, Dennis

    2017-09-01

    Fretting corrosion at the taper interface of modular hip implants has been implicated as a possible cause of implant failure. This study was set up to gain more insight in the taper mechanics that lead to fretting corrosion. The objectives of this study therefore were (1) to select experimental loading conditions to reproduce clinically relevant fretting corrosion features observed in retrieved components, (2) to develop a finite element model consistent with the fretting experiments and (3) to apply more complicated loading conditions of activities of daily living to the finite element model to study the taper mechanics. The experiments showed similar wear patterns on the taper surface as observed in retrievals. The finite element wear score based on Archard's law did not correlate well with the amount of material loss measured in the experiments. However, similar patterns were observed between the simulated micromotions and the experimental wear measurements. Although the finite element model could not be validated, the loading conditions based on activities of daily living demonstrate the importance of assembly load on the wear potential. These findings suggest that finite element models that do not incorporate geometry updates to account for wear loss may not be appropriate to predict wear volumes of taper connections.

  11. Chronic Administration of Oil Palm (Elaeis guineensis Leaves Extract Attenuates Hyperglycaemic-Induced Oxidative Stress and Improves Renal Histopathology and Function in Experimental Diabetes

    Directory of Open Access Journals (Sweden)

    Varatharajan Rajavel

    2012-01-01

    Full Text Available Oil palm (Elaeis guineensis leaves extract (OPLE has antioxidant properties and because oxidative stress contributes to the pathogenesis of diabetic nephropathy (DN, we tested the hypothesis that OPLE prevents diabetes renal oxidative stress, attenuating injury. Sprague-Dawley rats received OPLE (200 and 500 mg kg−1 for 4 and 12 weeks after diabetes induction (streptozotocin 60 mg kg−1. Blood glucose level, body and kidney weights, urine flow rate (UFR, glomerular filtration rate (GFR, and proteinuria were assessed. Oxidative stress variables such as 8-hydroxy-2′-deoxyguanosine (8-OHdG, glutathione (GSH, and lipid peroxides (LPO were quantified. Renal morphology was analysed, and plasma transforming growth factor-beta1 (TGF-β1 was measured. Diabetic rats demonstrated increase in blood glucose and decreased body and increased kidney weights. Renal dysfunction (proteinuria, elevations in UFR and GFR was observed in association with increases in LPO, 8-OHdG, and TGF-β1 and a decrease in GSH. Histological evaluation of diabetic kidney demonstrated glomerulosclerosis and tubulointerstitial fibrosis. OPLE attenuated renal dysfunction, improved oxidative stress markers, and reduced renal pathology in diabetic animals. These results suggest OPLE improves renal dysfunction and pathology in diabetes by reducing oxidative stress; furthermore, the protective effect of OPLE against renal damage in diabetes depends on the dose of OPLE as well as progression of DN.

  12. Chronic Administration of Oil Palm (Elaeis guineensis) Leaves Extract Attenuates Hyperglycaemic-Induced Oxidative Stress and Improves Renal Histopathology and Function in Experimental Diabetes.

    Science.gov (United States)

    Rajavel, Varatharajan; Abdul Sattar, Munavvar Zubaid; Abdulla, Mahmood Ameen; Kassim, Normadiah M; Abdullah, Nor Azizan

    2012-01-01

    Oil palm (Elaeis guineensis) leaves extract (OPLE) has antioxidant properties and because oxidative stress contributes to the pathogenesis of diabetic nephropathy (DN), we tested the hypothesis that OPLE prevents diabetes renal oxidative stress, attenuating injury. Sprague-Dawley rats received OPLE (200 and 500 mg kg(-1)) for 4 and 12 weeks after diabetes induction (streptozotocin 60 mg kg(-1)). Blood glucose level, body and kidney weights, urine flow rate (UFR), glomerular filtration rate (GFR), and proteinuria were assessed. Oxidative stress variables such as 8-hydroxy-2'-deoxyguanosine (8-OHdG), glutathione (GSH), and lipid peroxides (LPO) were quantified. Renal morphology was analysed, and plasma transforming growth factor-beta1 (TGF-β1) was measured. Diabetic rats demonstrated increase in blood glucose and decreased body and increased kidney weights. Renal dysfunction (proteinuria, elevations in UFR and GFR) was observed in association with increases in LPO, 8-OHdG, and TGF-β1 and a decrease in GSH. Histological evaluation of diabetic kidney demonstrated glomerulosclerosis and tubulointerstitial fibrosis. OPLE attenuated renal dysfunction, improved oxidative stress markers, and reduced renal pathology in diabetic animals. These results suggest OPLE improves renal dysfunction and pathology in diabetes by reducing oxidative stress; furthermore, the protective effect of OPLE against renal damage in diabetes depends on the dose of OPLE as well as progression of DN.

  13. Experimental analyses of the function of the proepicardium using a new microsurgical procedure to induce loss-of-proepicardial-function in chick embryos.

    Science.gov (United States)

    Männer, Jörg; Schlueter, Jan; Brand, Thomas

    2005-08-01

    The proepicardium (PE) is a primarily extracardiac progenitor cell population that colonizes the embryonic heart and delivers the epicardium, the subepicardial and intramyocardial fibroblasts, and the coronary vessels. Recent data show that PE-derived cells additionally play important regulatory roles in myocardial development and possibly in the normal morphogenesis of the heart. Developmental Dynamics 233, 2005. Research on the latter topics profits from the fact that loss-of-PE-function can be experimentally induced in chick embryos. So far, two microsurgical techniques were used to produce such embryos: (1) blocking of PE cell transfer with pieces of the eggshell membrane, and (2) mechanical excision of PE. Both of these techniques, however, have their shortcomings. We have searched, therefore, for new techniques to eliminate the PE. Here, we show that loss-of-PE-function can be induced by photoablation of the PE. Chick embryos were treated in ovo by means of a window in the eggshell at Hamburger and Hamilton (HH) stage 16 (iday 3). The pericardial coelom was opened, and the PE was externally stained with a 1% solution of Rose Bengal by means of a micropipette. Photoactivation of the dye was accomplished by illumination of the operation field with visible light. Examination on postoperative day 1 (iday 4, HH stages 19/20) disclosed complete removal of PE in every experimental embryo. On iday 9 (HH stages 33/34), the survival rate of experimental embryos was 35.7% (15 of 42). Development of the PE-derivatives was compromised in the heart of every survivor. The abnormalities encompassed hydro- or hemopericardium, epicardium-free areas with aneurysmatic outward bulging of the ventricular wall, thin myocardium, defects of the coronary vasculature, and abnormal tissue bridges between the ventricles and the pericardial wall. Our results show that photoablation of the PE is a powerful technique to induce long-lasting loss-of-PE-function in chick embryos. We have

  14. Genome-wide analyses of SWEET family proteins reveal involvement in fruit development and abiotic/biotic stress responses in banana.

    Science.gov (United States)

    Miao, Hongxia; Sun, Peiguang; Liu, Qing; Miao, Yulu; Liu, Juhua; Zhang, Kaixing; Hu, Wei; Zhang, Jianbin; Wang, Jingyi; Wang, Zhuo; Jia, Caihong; Xu, Biyu; Jin, Zhiqiang

    2017-06-14

    Sugars Will Eventually be Exported Transporters (SWEET) are a novel type of sugar transporter that plays crucial roles in multiple biological processes. From banana, for the first time, 25 SWEET genes which could be classified into four subfamilies were identified. Majority of MaSWEETs in each subfamily shared similar gene structures and conserved motifs. Comprehensive transcriptomic analysis of two banana genotypes revealed differential expression patterns of MaSWEETs in different tissues, at various stages of fruit development and ripening, and in response to abiotic and biotic stresses. More than 80% MaSWEETs were highly expressed in BaXi Jiao (BX, Musa acuminata AAA group, cv. Cavendish), in sharp contrast to Fen Jiao (FJ, M. acuminata AAB group) when pseudostem was first emerged. However, MaSWEETs in FJ showed elevated expression under cold, drought, salt, and fungal disease stresses, but not in BX. Interaction networks and co-expression assays further revealed that MaSWEET-mediated networks participate in fruit development signaling and abiotic/biotic stresses, which was strongly activated during early stage of fruit development in BX. This study provides new insights into the complex transcriptional regulation of SWEETs, as well as numerous candidate genes that promote early sugar transport to improve fruit quality and enhance stress resistance in banana.

  15. All-Atom Molecular-Level Computational Analyses of Polyurea/Fused-Silica Interfacial Decohesion Caused by Impinging Tensile Stress-Waves

    Science.gov (United States)

    2014-01-01

    Interfacial decohesion, Reactive forcefields Paper type Research paper International Journal of Structural Integrity Vol. 5 No. 4, 2014 pp. 339-367 © Emerald ...interaction was conducted to provide additional insight into the outcome of the stress-wave/interface interactions. 4. Results and discussion The main emphasis

  16. The relationship of violence and traumatic stress to changes in weight and waist circumference: longitudinal analyses from the study of women's health across the nation.

    Science.gov (United States)

    Garcia, Lorena; Qi, Lihong; Rasor, Marianne; Clark, Cari Jo; Bromberger, Joyce; Gold, Ellen B

    2014-05-01

    This article investigates the associations of violence and traumatic stress with changes in weight and waist circumference, hypothesizing that violence in midlife would be associated with increases or decreases in weight and waist circumference. The longitudinal cohort of the Study of Women's Health Across the Nation comprised the study sample, which included an ethnically/racially and socially diverse group of 2,870 women between the ages of 42 and 52 years at baseline. Women were followed annually for 10 years, and assessments included weight and waist circumference measures and data on violence, health outcomes, and confounders. At baseline, 8.6% Caucasian, 10.8% African American, 9.2% Chinese, and 5.0% Japanese women reported violence and traumatic stress. Reporting violence and traumatic stress during follow-up was significantly associated with weight gain (odds ratio [OR] = 2.39, 95% confidence interval [CI] = [1.28-4.47]), weight loss (OR = 3.54, 95% CI = [1.73-7.22]), and gain (OR = 2.44, 95% CI = [1.37-4.37]) or loss (OR = 2.66, 95% CI = [1.23-5.77]) in waist circumference, adjusting for age, race/ethnicity, education, marital status, and smoking. Violence and traumatic stress against midlife women were associated with gains or losses in weight and waist circumference.

  17. Gene Expression Responses to FUS, EWS, and TAF15 Reduction and Stress Granule Sequestration Analyses Identifies FET-Protein Non-Redundant Functions

    DEFF Research Database (Denmark)

    Blechingberg, Jenny; Luo, Yonglun; Bolund, Lars

    2012-01-01

    in amyotrophic lateral sclerosis, frontotemporal lobar degeneration, and trinucleotide repeat expansion diseases. We here describe a comparative characterization of FET-protein localization and gene regulatory functions. We show that FUS and TAF15 locate to cellular stress granules to a larger extend than EWS...

  18. Experimental and genetic analyses reveal that inbreeding depression declines with increased self-fertilization among populations of a coastal dune plant.

    Science.gov (United States)

    Dart, S; Eckert, C G

    2013-03-01

    Theory predicts that inbreeding depression (ID) should decline via purging in self-fertilizing populations. Yet, intraspecific comparisons between selfing and outcrossing populations are few and provide only mixed support for this key evolutionary process. We estimated ID for large-flowered (LF), predominantly outcrossing vs. small-flowered (SF), predominantly selfing populations of the dune endemic Camissoniopsis cheiranthifolia by comparing selfed and crossed progeny in glasshouse environments differing in soil moisture, and by comparing allozyme-based estimates of the proportion of seeds selfed and inbreeding coefficient of mature plants. Based on lifetime measures of dry mass and flower production, ID was stronger in nine LF populations [mean δ = 1-(fitness of selfed seed/fitness of outcrossed seed) = 0.39] than 16 SF populations (mean δ = 0.03). However, predispersal ID during seed maturation was not stronger for LF populations, and ID was not more pronounced under simulated drought, a pervasive stress in sand dune habitat. Genetic estimates of δ were also higher for four LF (δ = 1.23) than five SF (δ = 0.66) populations; however, broad confidence intervals around these estimates overlapped. These results are consistent with purging, but selective interference among loci may be required to maintain strong ID in partially selfing LF populations, and trade-offs between selfed and outcrossed fitness are likely required to maintain outcrossing in SF populations. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  19. IMFIT Integrated Modeling Applications Supporting Experimental Analysis: Multiple Time-Slice Kinetic EFIT Reconstructions, MHD Stability Limits, and Energy and Momentum Flux Analyses

    Science.gov (United States)

    Collier, A.; Lao, L. L.; Abla, G.; Chu, M. S.; Prater, R.; Smith, S. P.; St. John, H. E.; Guo, W.; Li, G.; Pan, C.; Ren, Q.; Park, J. M.; Bisai, N.; Srinivasan, R.; Sun, A. P.; Liu, Y.; Worrall, M.

    2010-11-01

    This presentation summarizes several useful applications provided by the IMFIT integrated modeling framework to support DIII-D and EAST research. IMFIT is based on Python and utilizes modular task-flow architecture with a central manager and extensive GUI support to coordinate tasks among component modules. The kinetic-EFIT application allows multiple time-slice reconstructions by fetching pressure profile data directly from MDS+ or from ONETWO or PTRANSP. The stability application analyzes a given reference equilibrium for stability limits by performing parameter perturbation studies with MHD codes such as DCON, GATO, ELITE, or PEST3. The transport task includes construction of experimental energy and momentum fluxes from profile analysis and comparison against theoretical models such as MMM95, GLF23, or TGLF.

  20. Individual vs. combinatorial effect of elevated CO2 conditions and salinity stress on Arabidopsis thaliana liquid cultures: Comparing the early molecular response using time-series transcriptomic and metabolomic analyses

    Directory of Open Access Journals (Sweden)

    Dutta Bhaskar

    2010-12-01

    Full Text Available Abstract Background In this study, we investigated the individual and combinatorial effect of elevated CO2 conditions and salinity stress on the dynamics of both the transcriptional and metabolic physiology of Arabidopsis thaliana liquid hydroponic cultures over the first 30 hours of continuous treatment. Both perturbations are of particular interest in plant and agro-biotechnological applications. Moreover, within the timeframe of this experiment, they are expected to affect plant growth to opposite directions. Thus, a major objective was to investigate whether this expected "divergence" was valid for the individual perturbations and to study how it is manifested under the combined stress at two molecular levels of cellular function, using high-throughput analyses. Results We observed that a high salinity has stronger effect than elevated CO2 at both the transcriptional and metabolic levels, b the transcriptional responses to the salinity and combined stresses exhibit strong similarity, implying a robust transcriptional machinery acting to the salinity stress independent of the co-occurrence of elevated CO2, c the combinatorial effect of the two perturbations on the metabolic physiology is milder than of the salinity stress alone. Metabolomic analysis suggested that the beneficial role of elevated CO2 on salt-stressed plants within the timeframe of this study should be attributed to the provided additional resources; these allow the plants to respond to high salinity without having to forfeit other major metabolic functions, and d 9 h-12 h and 24 h of treatment coincide with significant changes in the metabolic physiology under any of the investigated stresses. Significant differences between the acute and longer term responses were observed at both molecular levels. Conclusions This study contributes large-scale dynamic omic data from two levels of cellular function for a plant system under various stresses. It provides an additional example

  1. Transcriptome wide analyses reveal a sustained cellular stress response in the gill tissue of Trematomus bernacchii after acclimation to multiple stressors.

    Science.gov (United States)

    Huth, Troy J; Place, Sean P

    2016-02-20

    As global climate change progresses, the Southern Ocean surrounding Antarctica is poised to undergo potentially rapid and substantial changes in temperature and pCO2. To survive in this challenging environment, the highly cold adapted endemic fauna of these waters must demonstrate sufficient plasticity to accommodate these changing conditions or face inexorable decline. Previous studies of notothenioids have focused upon the short-term response to heat stress; and more recently the longer-term physiological response to the combined stress of increasing temperatures and pCO2. This inquiry explores the transcriptomic response of Trematomus bernacchii to increased temperatures and pCO2 at 7, 28 and 56 days, in an attempt to discern the innate plasticity of T. bernacchii available to cope with a changing Southern Ocean. Differential gene expression analysis supported previous research in that T. bernacchii exhibits no inducible heat shock response to stress conditions. However, T. bernacchii did demonstrate a strong stress response to the multi-stressor condition in the form of metabolic shifts, DNA damage repair, immune system processes, and activation of apoptotic pathways combined with negative regulation of cell proliferation. This response declined in magnitude over time, but aspects of this response remained detectable throughout the acclimation period. When exposed to the multi-stressor condition, T. bernacchii demonstrates a cellular stress response that persists for a minimum of 7 days before returning to near basal levels of expression at longer acclimation times. However, subtle changes in expression persist in fish acclimated for 56 days that may significantly affect the fitness T. bernacchii over time.

  2. mTOR inhibition increases cell viability via autophagy induction during endoplasmic reticulum stress – An experimental and modeling study

    Directory of Open Access Journals (Sweden)

    Orsolya Kapuy

    2014-01-01

    Full Text Available Unfolded or misfolded proteins in the endoplasmic reticulum (ER trigger an adaptive ER stress response known as unfolded protein response (UPR. Depending on the severity of ER stress, either autophagy-controlled survival or apoptotic cell death can be induced. The molecular mechanisms by which UPR controls multiple fate decisions have started to emerge. One such molecular mechanism involves a master regulator of cell growth, mammalian target of rapamycin (mTOR, which paradoxically is shown to have pro-apoptotic role by mutually interacting with ER stress response. How the interconnections between UPR and mTOR influence the dynamics of autophagy and apoptosis activation is still unclear. Here we make an attempt to explore this problem by using experiments and mathematical modeling. The effect of perturbed mTOR activity in ER stressed cells was studied on autophagy and cell viability by using agents causing mTOR pathway inhibition (such as rapamycin or metyrapone. We observed that mTOR inhibition led to an increase in cell viability and was accompanied by an increase in autophagic activity. It was also shown that autophagy was activated under conditions of severe ER stress but that in the latter phase of stress it was inhibited at the time of apoptosis activation. Our mathematical model shows that both the activation threshold and temporal dynamics of autophagy and apoptosis inducers are sensitive to variation in mTOR activity. These results confirm that autophagy has cytoprotective role and is activated in mutually exclusive manner with respect to ER stress levels.

  3. Experimental investigation on the coupled effect of effective stress and gas slippage on the permeability of shale.

    Science.gov (United States)

    Yang, Diansen; Wang, Wei; Chen, Weizhong; Wang, Shugang; Wang, Xiaoqiong

    2017-03-17

    Permeability is one of the most important parameters to evaluate gas production in shale reservoirs. Because shale permeability is extremely low, gas is often used in the laboratory to measure permeability. However, the measured apparent gas permeability is higher than the intrinsic permeability due to the gas slippage effect, which could be even more dominant for materials with nanopores. Increasing gas pressure during tests reduces gas slippage effect, but it also decreases the effective stress which in turn influences the permeability. The coupled effect of gas slippage and effective stress on shale permeability remains unclear. Here we perform laboratory experiments on Longmaxi shale specimens to explore the coupled effect. We use the pressure transient method to measure permeability under different stress and pressure conditions. Our results reveal that the apparent measured permeability is controlled by these two competing effects. With increasing gas pressure, there exists a pressure threshold at which the dominant effect on permeability switches from gas slippage to effective stress. Based on the Klinkenberg model, we propose a new conceptual model that incorporates both competing effects. Combining microstructure analysis, we further discuss the roles of stress, gas pressure and water contents on gas permeability of shale.

  4. Deletion of p66Shc longevity gene protects against experimental diabetic glomerulopathy by preventing diabetes-induced oxidative stress.

    Science.gov (United States)

    Menini, Stefano; Amadio, Lorena; Oddi, Giovanna; Ricci, Carlo; Pesce, Carlo; Pugliese, Francesco; Giorgio, Marco; Migliaccio, Enrica; Pelicci, PierGiuseppe; Iacobini, Carla; Pugliese, Giuseppe

    2006-06-01

    p66(Shc) regulates both steady-state and environmental stress-dependent reactive oxygen species (ROS) generation. Its deletion was shown to confer resistance to oxidative stress and protect mice from aging-associated vascular disease. This study was aimed at verifying the hypothesis that p66(Shc) deletion also protects from diabetic glomerulopathy by reducing oxidative stress. Streptozotocin-induced diabetic p66(Shc) knockout (KO) mice showed less marked changes in renal function and structure, as indicated by the significantly lower levels of proteinuria, albuminuria, glomerular sclerosis index, and glomerular and mesangial areas. Glomerular content of fibronectin and collagen IV was also lower in diabetic KO versus wild-type mice, whereas apoptosis was detected only in diabetic wild-type mice. Serum and renal tissue advanced glycation end products and plasma isoprostane 8-epi-prostaglandin F2alpha levels and activation of nuclear factor kappaB (NF-kappaB) were also lower in diabetic KO than in wild-type mice. Mesangial cells from KO mice grown under high-glucose conditions showed lower cell death rate, matrix production, ROS levels, and activation of NF-kappaB than those from wild-type mice. These data support a role for oxidative stress in the pathogenesis of diabetic glomerulopathy and indicate that p66(Shc) is involved in the molecular mechanism(s) underlying diabetes-induced oxidative stress and oxidant-dependent renal injury.

  5. An experimental approach to assess Corbicula fluminea (Müller, 1774) resistance to osmotic stress in estuarine habitats

    Science.gov (United States)

    Ferreira-Rodríguez, Noé; Pardo, Isabel

    2016-07-01

    Corbicula fluminea arrived in the Miño Estuary in 1989 and, from there, colonized more than 150 km upstream. Our aim was to test the capacity of C. fluminea to cope with osmotic stress conditions previously to invade new freshwater habitats through estuaries. Based on previously collected information, the experiment aims to study the response of the species to marine osmotic stress, evaluated by survival and behaviour. Experiments determined the resistance by the species to various levels of osmotic stress, and recovery time after exposure to high salinity levels, representative of the temporal and spatial salinity variation existing in the estuary. Under osmotic stress the semi-maximum response was reached after 19 days exposure. The species tolerance range, measured by individual maintained activity, was at salinity ∼20 when exposed to winter temperatures, while when animals were exposed to summer ones its tolerance was reduced to salinity lower than 15. C. fluminea show a large physiological flexibility to cope with salinity variations in estuaries. In summer, the temperature increases the metabolic rate thus making the species more vulnerable to osmotic stress exposure. These findings are relevant to preventing new invasions through ship ballast waters ensuring complete mortality if individuals are retained for >26 days.

  6. Experimental and numerical analyses on a plate heat exchanger with phase change for waste heat recovery at off-design conditions

    Science.gov (United States)

    Cipollone, Roberto; Bianchi, Giuseppe; Di Battista, Davide; Fatigati, Fabio

    2015-11-01

    This paper analyzes the performances of an evaporator for small scale waste heat recovery applications based on bottoming Organic Rankine Cycles with net output power in the range 2-5 kW. The heat recovery steam generator is a plate heat exchanger with oil as hot stream and an organic fluid on the cold side. An experimental characterization of the heat exchanger was carried out at different operating points measuring temperatures, pressures and flow rates on both sides. The measurement data further allowed to validate a numerical model of the evaporator whereas heat transfer coefficients were evaluated comparing several literature correlations, especially for the phase-change of the organic fluid. With reference to a waste heat recovery application in industrial compressed air systems, multiple off-design conditions were simulated considering the effects of oil mass flow rate and temperature on the superheating of the organic fluid, a key parameter to ensure a proper operation of the expansion machine, thus of the energy recovery process.

  7. Improved sample manipulation at the STRESS-SPEC neutron diffractometer using an industrial 6-axis robot for texture and strain analyses

    Energy Technology Data Exchange (ETDEWEB)

    Randau, C. [Institute for Materials Science and Engineering, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld (Germany); Brokmeier, H.G., E-mail: heinz-guenter.brokmeier@tu-clausthal.de [Institute for Materials Science and Engineering, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld (Germany); Institute of Materials Research, Helmholtz-Centre Geesthacht, D-21502 Geesthacht (Germany); Gan, W.M. [Institute of Materials Research, Helmholtz-Centre Geesthacht, D-21502 Geesthacht (Germany); Hofmann, M.; Voeller, M. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU München, D-85747 Garching (Germany); Tekouo, W. [Institute for Machine Tools and Industrial Management, TU München, D-85747 Garching (Germany); Al-hamdany, N. [Institute for Materials Science and Engineering, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld (Germany); Seidl, G. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU München, D-85747 Garching (Germany); Schreyer, A. [Institute of Materials Research, Helmholtz-Centre Geesthacht, D-21502 Geesthacht (Germany)

    2015-09-11

    The materials science neutron diffractometer STRESS-SPEC located at FRM II is a dedicated instrument for strain and pole figure measurements. Both methods make complementary demands on sample handling. On one hand pole figure measurements need a high degree of freedom to orient small samples and on the other hand in strain investigations it is often necessary to handle large and heavy components. Therefore a robot based sample positioning system was developed, which has the capability to provide both possibilities. Based on this new robot system further developments like a full automated sample changer system for texture measurements were accomplished. Moreover this system opens the door for combined strain and texture analysis at STRESS-SPEC.

  8. Experimental and Analytical Investigation of Deformations and Stress Distribution in Steel Bands of a Two-Span Stress-Ribbon Pedestrian Bridge

    Directory of Open Access Journals (Sweden)

    G. Sandovic

    2017-01-01

    Full Text Available The article is dedicated to the analysis of problems related to design of pedestrian bridges with flexible ribbon bands made of steel. The study is based on test results of a bridge model that has two spans (each with a length of five meters. A simplified analytical technique has been proposed for predicting vertical deformations of the bridge structure subjected to symmetrical or asymmetrical loading patterns. The technique also allows assessing the tension forces in the ribbons, which are very important for design of such structures. The analysis reveals the importance of the flexural rigidity of the ribbons that might cause significant redistribution of stresses within the steel bands.

  9. An experimental setup for studying the core-excited atoms and molecules by electron impact using energy analysed electron-ion coincidence technique

    Science.gov (United States)

    Kumar, S.; Prajapati, S.; Singh, B.; Singh, B. K.; Shanker, R.

    2017-07-01

    Operation and performance of an apparatus for studying the decay dynamics relevant to core-hole decay processes in atoms and molecules excited by energetic electrons using an energy analysed electron-ion coincidence technique are described in some detail. The setup consists of a time- and position sensitive double-field linear TOF mass spectrometer coupled with a dual MCP detector and a single-pass CMA to select the energy of detected electrons. Details of different components involved in the setup are presented and discussed. To demonstrate the performance and capability of the apparatus, we present some typical results extracted from the TOF argon ion-mass spectra observed in coincidence with 18-energy selected electrons emitted from interaction of a continuous beam of 3.5 keV electrons with a dilute gaseous target of argon atoms. Specifically, the variation of relative correlation probability for the final ion-charge states Ar1+ to Ar4+ produced in the considered collision reactions as a function of energy of emitted electrons is determined and discussed.

  10. Methodologies and experimental platforms for generating and analysing microarray and mass spectrometry-based omics data to support P4 medicine.

    Science.gov (United States)

    Guzzi, Pietro H; Agapito, Giuseppe; Milano, Marianna; Cannataro, Mario

    2016-07-01

    Predictive, preventive, personalized and participatory (P4) medicine is an emerging medical model that is based on the customization of all medical aspects (i.e. practices, drugs, decisions) of the individual patient. P4 medicine presupposes the elucidation of the so-called omic world, under the assumption that this knowledge may explain differences of patients with respect to disease prevention, diagnosis and therapies. Here, we elucidate the role of some selected omics sciences for different aspects of disease management, such as early diagnosis of diseases, prevention of diseases, selection of personalized appropriate and optimal therapies based on molecular profiling of patients. After introducing basic concepts of P4 medicine and omics sciences, we review some computational tools and approaches for analysing selected omics data, with a special focus on microarray and mass spectrometry data, which may be used to support P4 medicine. Some applications of biomarker discovery and pharmacogenomics and some experiences on the study of drug reactions are also described. © The Author 2015. Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  11. Source duration of stress and water-pressure induced seismicity derived from experimental analysis of P wave pulse width in granite

    Science.gov (United States)

    Masuda, K.

    2013-12-01

    Pulse widths of P waves in granite, measured in the laboratory, were analyzed to investigate source durations of rupture processes for water-pressure induced and stress-induced microseismicity. Much evidence suggests that fluids in the subsurface are intimately linked to faulting processes. Studies of seismicity induced by water injection are thus important for understanding the trigger mechanisms of earthquakes as well as for engineering applications such as hydraulic fracturing of rocks at depth for petroleum extraction. Determining the cause of seismic events is very important in seismology and engineering; however, water-pressure induced seismic events are difficult to distinguish from those induced by purely tectonic stress. To investigate this problem, we analyzed the waveforms of acoustic emissions (AEs) produced in the laboratory by both water-pressure induced and stress-induced microseismicity. We used a cylinder (50 mm in diameter and 100 mm in length) of medium-grained granite. We applied a differential stress of about 70% of fracture strength, to the rock sample under 40 MPa confining pressure and held it constant throughout the experiment. When the primary creep stage and acoustic emissions (AEs) caused by the initial loading had ceased, we injected distilled water into the bottom end of the sample at a constant pressure of 17 MPa until macroscopic fracture occurred. We analysed AE waveforms produced by stress-induced AEs which occurred before the water-injection and by water-pressure induced AEs which occurred after the water-injection. Pulse widths were measured from the waveform traces plotted from the digital data. To investigate the source duration of the rupture process, we estimated the pulse width at the source and normalized by event magnitude to obtain a scaled pulse width at the source. After the effects of event size and hypocentral distance were removed from observed pulse widths, the ratio of the scaled source durations of water

  12. Protocol for an experimental investigation of the roles of oxytocin and social support in neuroendocrine, cardiovascular, and subjective responses to stress across age and gender

    Directory of Open Access Journals (Sweden)

    Block Jason

    2009-12-01

    Full Text Available Abstract Background Substantial empirical evidence has demonstrated that individuals who are socially isolated or have few positive social connections seem to age at a faster rate and have more chronic diseases. Oxytocin is a neurohypophyseal hormone hypothesized to coordinate both the causes and effects of positive social interactions, and may be involved in positive physiological adaptations such as buffering the deleterious effects of stress and promoting resilience. The proposed research will examine whether and how oxytocin influences responses to stress in humans and will consider effects in relation to those of social support. Methods/Design Experimental research will be used to determine whether exogenously administered oxytocin (intranasal influences psychological and physiological outcomes under conditions of stress across gender and age in adulthood. Hypotheses to be tested are: 1 Oxytocin ameliorates the deleterious neuroendocrine, cardiovascular, and subjective effects of stress; 2 Oxytocin and social support have similar and additive stress-buffering effects; 3 Oxytocin effects are stronger in women versus men; and 4 Oxytocin effects are similar across a range of adult ages. Hypotheses will be tested with a placebo-controlled, double-blind study using a sample of healthy men and women recruited from the community. Participants are randomly assigned to receive either oxytocin or placebo. They undergo a social stress manipulation with and without social support (randomly assigned, and outcome measures are obtained at multiple times during the procedure. Discussion Understanding the determinants of healthy aging is a major public health priority and identifying effective measures to prevent or delay the onset of chronic diseases is an important goal. Experimental research on oxytocin, social relationships, and health in adulthood will contribute to the scientific knowledge base for maximizing active life and health expectancy. At

  13. EXPERIMENTAL AND THEORETICAL STUDIES OF THE STRESS-STRAIN STATE OF WOOD-CONCRETE AND WOOD-GYPSUM MASONRY

    Directory of Open Access Journals (Sweden)

    Likhacheva Svetlana Yur'evna

    2012-12-01

    The findings of the prototype testing include identification of the two areas of deformations: areas of elastic deformations and areas of intensive development of deformations. The first area of partial elastic deformations is characterized by the linear stress function, while the second area demonstrates that this relationship is nonlinear. Permanent deformations appear as of the startup of the loading process and disproportionate stress is demonstrated throughout the deformation process. However, in the first area (partial elastic deformations residual deformations are so small that this area is considered as the area of "the area of incomplete elasticity".

  14. Development of a high pressure automated lag time apparatus for experimental studies and statistical analyses of nucleation and growth of gas hydrates.

    Science.gov (United States)

    Maeda, Nobuo; Wells, Darrell; Becker, Norman C; Hartley, Patrick G; Wilson, Peter W; Haymet, Anthony D J; Kozielski, Karen A

    2011-06-01

    Nucleation in a supercooled or a supersaturated medium is a stochastic event, and hence statistical analyses are required for the understanding and prediction of such events. The development of reliable statistical methods for quantifying nucleation probability is highly desirable for applications where control of nucleation is required. The nucleation of gas hydrates in supercooled conditions is one such application. We describe the design and development of a high pressure automated lag time apparatus (HP-ALTA) for the statistical study of gas hydrate nucleation and growth at elevated gas pressures. The apparatus allows a small volume (≈150 μl) of water to be cooled at a controlled rate in a pressurized gas atmosphere, and the temperature of gas hydrate nucleation, T(f), to be detected. The instrument then raises the sample temperature under controlled conditions to facilitate dissociation of the gas hydrate before repeating the cooling-nucleation cycle again. This process of forming and dissociating gas hydrates can be automatically repeated for a statistically significant (>100) number of nucleation events. The HP-ALTA can be operated in two modes, one for the detection of hydrate in the bulk of the sample, under a stirring action, and the other for the detection of the formation of hydrate films across the water-gas interface of a quiescent sample. The technique can be applied to the study of several parameters, such as gas pressure, cooling rate and gas composition, on the gas hydrate nucleation probability distribution for supercooled water samples. © 2011 American Institute of Physics

  15. Concurrent targeting of nitrosative stress-PARP pathway corrects functional, behavioral and biochemical deficits in experimental diabetic neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Negi, Geeta; Kumar, Ashutosh [Molecular Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S.A.S. Nagar, Punjab 160062 (India); Sharma, Shyam S., E-mail: sssharma@niper.ac.in [Molecular Neuropharmacology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S.A.S. Nagar, Punjab 160062 (India)

    2010-01-01

    Peroxynitrite mediated nitrosative stress, an indisputable initiator of DNA damage and overactivation of poly(ADP-ribose) polymerase (PARP), a nuclear enzyme activated after sensing DNA damage, are two crucial pathogenetic mechanisms in diabetic neuropathy. The intent of the present study was to investigate the effect of combination of a peroxynitrite decomposition catalyst (PDC), FeTMPyP and a PARP inhibitor, 4-ANI against diabetic peripheral neuropathy. The end points of evaluation of the study included motor nerve conduction velocity (MNCV) and nerve blood flow (NBF) for evaluating nerve functions; thermal hyperalgesia and mechanical allodynia for assessing nociceptive alterations, malondialdehyde and peroxynitrite levels to detect oxidative stress-nitrosative stress; NAD concentration in sciatic nerve to assess overactivation of PARP. Additionally immunohistochemical studies for nitrotyrosine and Poly(ADP-ribose) (PAR) was also performed. Treatment with the combination of FeTMPyP and 4-ANI led to significant improvement in nerve functions and pain parameters and also attenuated the oxidative-nitrosative stress markers. Further, the combination also reduced the overactivation of PARP as evident from increased NAD levels and decreased PAR immunopositivity in sciatic nerve microsections. Thus, it can be concluded that treatment with the combination of a PDC and PARP inhibitor attenuates alteration in peripheral nerves in diabetic neuropathy (DN).

  16. Effect of Tyr-MIF-1 peptides on blood ACTH and corticosterone concentration induced by three experimental models of stress.

    Science.gov (United States)

    Bocheva, A; Dzambazova, E; Hadjiolova, R; Traikov, L; Mincheva, R; Bivolarski, I

    2008-10-01

    1. Studies, using a wide variety of stressors, have clearly indicated that the pattern of neuroendocrine response is dependent upon the stress stimulus applied. 2. The Tyr-MIF-1 family of peptides (Tyr-MIF-1s) includes MIF-1, Tyr-MIF-1, Tyr-W-MIF-1 and Tyr-K-MIF-1. These neuropeptides, neuromodulators are able to inhibit the expression of some forms of stress-induced analgesia. 3. The aim of this study was to compare changes in ACTH and corticosterone (CORT) concentration after various stressors (immobilization, cold and heat), as well as after injection of investigated Tyr-MIF-1s peptides. 4. According to our results, hypothalamic-pituitary-adrenal (HPA) system was activated by all the stressors applied. Heat and immobilization are stronger stressors, as the exposure of animals to a high ambient temperature and immobilization resulted in the highest rise of plasma ACTH and CORT concentration when compared with cold stress. Moreover, all the investigated peptides from Tyr-MIF-1 family, administered after application of stressors, inhibited the elevations in adrenocorticotropic hormone (ACTH) and corticosterone (CORT) plasma concentrations significantly. 5. In conclusion, the various stressors applied seem to induce a different response of the HPA system as judged by quantitative changes in ACTH and CORT release. We suggest that Tyr-MIF-1 peptides may possess anti-stressor effects, as they inhibited stress-induced rising in two hormones that were investigated.

  17. Early Social Deprivation and the Social Buffering of Cortisol Stress Responses in Late Childhood: An Experimental Study

    Science.gov (United States)

    Hostinar, Camelia E.; Johnson, Anna E.; Gunnar, Megan R.

    2015-01-01

    The goal of the present study was to investigate the role of early social deprivation in shaping the effectiveness of parent support to alleviate hypothalamic-pituitary-adrenal (HPA)-axis-stress responses of children (ages 8.9-11, M = 9.83 years, SD = 0.55). The sample was equally divided between children who had been adopted internationally from…

  18. Comparative analyses of genotoxicity, oxidative stress and antioxidative defence system under exposure of methyl parathion and hexaconazole in barley (Hordeum vulgare L.).

    Science.gov (United States)

    Dubey, Pragyan; Mishra, Amit Kumar; Singh, Ashok Kumar

    2015-12-01

    The present study aims to evaluate the comparative effects of methyl parathion and hexaconazole on genotoxicity, oxidative stress, antioxidative defence system and photosynthetic pigments in barley (Hordeum vulgare L. variety karan-16). The seeds were exposed with three different concentrations, i.e. 0.05, 0.1 and 0.5 % for 6 h after three pre-soaking durations 7, 17 and 27 h which represents G1, S and G2 phases of the cell cycle, respectively. Ethyl methane sulphonate, a well-known mutagenic agent and double distilled water, was used as positive and negative controls, respectively. The results indicate significant decrease in mitotic index with increasing concentrations of pesticides, and the extent was higher in methyl parathion. Chromosomal aberrations were found more frequent in methyl parathion than hexaconazole as compared to their respective controls. Treatment with the pesticides induced oxidative stress which was evident with higher contents of H2O2 and lipid peroxidation, and the increase was more prominent in methyl parathion. Contents of total phenolics were increased; however, soluble protein content showed a reverse trend. Among the enzymatic antioxidants, activities of superoxide dismutase and peroxidase were significantly up-regulated, and more increase was noticed in hexaconazole. Increments in total chlorophyll and carotenoid contents were observed up to 0.1 % but decreased at higher concentration (0.5 %), and the reductions were more prominent in methyl parathion than hexaconazole as compared to their respective controls. Methyl parathion treatment caused more damage in the plant cells of barley as compared to hexaconazole, which may be closely related to higher genotoxicity and oxidative stress.

  19. Development of a measuring and evaluation method for X-ray analysis of residual stresses in the surface region of polycrystalline materials; Entwicklung eines Mess- und Auswerteverfahrens zur roentgenographischen Analyse des Eigenspannungszustandes im Oberflaechenbereich vielkristalliner Werkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Genzel, C.

    2000-11-01

    The topic of the habilitation thesis is the development of an X-ray diffraction method for measurement and depth-resolved analysis of internal stresses in the surface region of polycrystalline materials. The method relies on the basic approach of varying {tau}, the penetration depth of the X-rays in the materials, by the scattering vector g{sub theta{psi}} via stepwise specimen rotation. Thus, depth profiles of the interlattice plane distances d(hkl) in the specimen system can be derived for given direction and inclination angles {theta} and {psi} of the scattering vector. This offers the possibility to identify individual components of the stress tensors of the basic equation of the X-ray diffraction analysis, and to perform separate analyses of those components. For calculation of the relevant internal stress distributions {sigma}{sub ij}({tau}) using the interlattice plane distance profiles, a self-consistent method is established which takes into account the high sensitivity of the derived internal stresses in relation to the interlattice plane distance d{sub 0}(hkl) in the stress-free crystal lattice. The evaluation yields results describing the depth profiles as well as the strain-free interlattice plane distance d{sub 0}(hkl), so that a quantitative analysis is possible of tri-axial internal stress states in the surface region of the materials. (orig./CB) [German] Den Gegenstand der vorliegenden Arbeit bildet die Entwicklung eines roentgenographischen Mess- und Auswerteverfahrens zur tiefenaufgeloesten Analyse des oberflaechennahen Eigenspannungszustandes in vielkristallinen Werkstoffen. Der Grundgedanke der Methode besteht darin, die Eindringtiefe {tau} der Roentgenstrahlung in den Werkstoff durch schrittweise Drehung der Probe um den Streuvektor g{sub {theta}}{sub {psi}} zu variieren. Damit koennen Tiefenprofile der Netzebenenabstaende d(hkl) fuer fest vorgegebene Azimut- und Neigungswinkel {theta} und {psi} des Streuvektors im Probensystem ermittelt

  20. Genome-wide identification, phylogeny, and expression analyses of the 14-3-3 family reveal their involvement in the development, ripening and abiotic stress response in banana

    Directory of Open Access Journals (Sweden)

    meiying li

    2016-09-01

    Full Text Available Plant 14-3-3 proteins act as critical components of various cellular signaling processes and play an important role in regulating multiple physiological processes. However, less information is known about the 14-3-3 gene family in banana. In this study, 25 14-3-3 genes were identified from the banana genome. Based on the evolutionary analysis, banana 14-3-3 proteins were clustered into ε and non-ε groups. Conserved motif analysis showed that all identified banana 14-3-3 genes had the typical 14-3-3 motif. The gene structure of banana 14-3-3 genes showed distinct class-specific divergence between the ε group and the non-ε group. Most banana 14-3-3 genes showed strong transcript accumulation changes during fruit development and postharvest ripening in two banana varieties, indicating that they might be involved in regulating fruit development and ripening. Moreover, some 14-3-3 genes also showed great changes after osmotic, cold, and salt treatments in two banana varieties, suggested their potential role in regulating banana response to abiotic stress. Taken together, this systemic analysis reveals the involvement of banana 14-3-3 genes in fruit development, postharvest ripening, and response to abiotic stress and provides useful information for understanding the functions of 14-3-3 genes in banana.

  1. An enhanced method with local energy minimization for the robust a posteriori construction of equilibrated stress fields in finite element analyses

    Science.gov (United States)

    Pled, Florent; Chamoin, Ludovic; Ladevèze, Pierre

    2012-03-01

    In the context of global/goal-oriented error estimation applied to computational mechanics, the need to obtain reliable and guaranteed bounds on the discretization error has motivated the use of residual error estimators. These estimators require the construction of admissible stress fields verifying the equilibrium exactly. This article focuses on a recent method, based on a flux-equilibration procedure and called the element equilibration + star-patch technique (EESPT), that provides for such stress fields. The standard version relies on a strong prolongation condition in order to calculate equilibrated tractions along finite element boundaries. Here, we propose an enhanced version, which is based on a weak prolongation condition resulting in a local minimization of the complementary energy and leads to optimal tractions in selected regions. Geometric and error estimate criteria are introduced to select the relevant zones for optimizing the tractions. We demonstrate how this optimization procedure is important and relevant to produce sharper estimators at affordable computational cost, especially when the error estimate criterion is used. Two- and three-dimensional numerical experiments demonstrate the efficiency of the improved technique.

  2. Grain scale stresses and strains determination by X-ray diffraction; Contribution a l'analyse par diffractometrie X des deformations et des contraintes a l'echelle des grains

    Energy Technology Data Exchange (ETDEWEB)

    Huang, W

    2007-03-15

    A new methodology for strain and stress analysis by X ray diffraction (XRD) in single crystal was developed. It can be applied to determine the second order stress (in grain scale) in single and multi-crystal material with non-cubic lattice. This method is based on the method Ortner I. It has introduced the metric tensor G which is deduced from the lattice space measured by XRD. In the developed method, when the crystal reference is non-orthonormal, an orthonormal reference associated with the crystal basis is defined, so all calculation could be done with usual calculation laws. The use of the least square method allows the acquisition of many more measurements than the six absolute necessary. Then a better metric tensor G is calculated and the statistical error is obtained. This developed method was applied in a bi crystal copper. The experimental results have shown that this method is also effective. The second order residuals stresses for coarse Zn grains in a galvanized coating were determined after annealing. The four coarse grains with different orientations were also characterized and demonstrated the elastic and plastic deformation mechanism in a grain or between the grains during in situ tensile loading. So this method is well able to determine the strains and stresses in grain scale in a mono crystal or multi crystal with any crystalline structure. (author)

  3. Stress vulnerability in adolescents with chronic fatigue syndrome: experimental study investigating heart rate variability and skin conductance responses.

    Science.gov (United States)

    Rimes, Katharine A; Lievesley, Kate; Chalder, Trudie

    2017-07-01

    Stress vulnerability has been implicated in adolescent chronic fatigue syndrome (CFS), but has rarely been investigated directly. This study compared psychological and physiological responses to a laboratory social performance task in adolescents with CFS with chronic illness (asthma) and healthy control groups. Adolescents with CFS (n = 60), adolescents with asthma (n = 31) and healthy adolescents (n = 78) completed questionnaires before and after a social performance task. Skin conductance responses (SCR; mean SCR and Max-Min) and heart rate variability (low frequency/high frequency; LF/HF and root mean square difference of successive RR intervals; RMSSD) was measured before, during and after the task. Baseline heart rate variability (HRV) (RMSSD) was significantly lower in the CFS and Asthma groups than the HC. During the speech, the CFS and Asthma groups had higher HRV (LF/HF) than the HC, adjusting for baseline LF/HF. Although the asthma group showed a subsequent reduction in HRV during recovery, the CFS group did not. Similarly, during recovery after the task, the CFS group showed a continued increase in skin conductance (Min-Max), unlike the Asthma and HC groups. Compared to control groups, adolescents with CFS expected to find the task more difficult, were more anxious beforehand and afterwards, rated it as more difficult, evaluated their performance more negatively and had lower observer ratings of performance. Parents of adolescents with CFS expected that their child would perform less well in the task than parents of control participants. Adolescents with CFS showed autonomic nervous system responses that are consistent with chronic stress vulnerability, difficulty coping with acute stress and slower recovery after acute stress. Self-report measures also indicated greater trait, pre- and posttask anxiety in the CFS group. © 2017 Association for Child and Adolescent Mental Health.

  4. Histology of experimental stress ulcer: the effect of cimetidine on adrenaline-induced gastric lesions in the rabbit.

    OpenAIRE

    Man, W K; Silcocks, P. B.; Waldes, R.; Spencer, J.

    1981-01-01

    The gastric mucosal injury produced by i.p. instillation of adrenaline in the rabbit was examined and assessed histologically. Mucosal lesions were classified by microscopy into two types bearing distinct histological features. In Type A oedema only was seen and in Type B erosion and/or haemorrhage were added. Statistical analysis revealed that mucosal lesions were related to adrenaline dose. Cimetidine was ineffective in protecting against the stress-related gastric lesion in the present rab...

  5. Antioxidant treatment ameliorates experimental diabetes-induced depressive-like behaviour and reduces oxidative stress in brain and pancreas.

    Science.gov (United States)

    Réus, Gislaine Z; Dos Santos, Maria Augusta B; Abelaira, Helena M; Titus, Stephanie E; Carlessi, Anelise S; Matias, Beatriz I; Bruchchen, Livia; Florentino, Drielly; Vieira, Andriele; Petronilho, Fabricia; Ceretta, Luciane B; Zugno, Alexandra I; Quevedo, João

    2016-03-01

    Studies have shown a relationship between diabetes mellitus (DM) and the development of major depressive disorder. Alterations in oxidative stress are associated with the pathophysiology of both diabetes mellitus and major depressive disorder. This study aimed to evaluate the effects of antioxidants N-acetylcysteine and deferoxamine on behaviour and oxidative stress parameters in diabetic rats. To this aim, after induction of diabetes by a single dose of alloxan, Wistar rats were treated with N-acetylcysteine or deferoxamine for 14 days, and then depressive-like behaviour was evaluated. Oxidative stress parameters were assessed in the prefrontal cortex, hippocampus, amygdala, nucleus accumbens and pancreas. Diabetic rats displayed depressive-like behaviour, and treatment with N-acetylcysteine reversed this alteration. Carbonyl protein levels were increased in the prefrontal cortex, hippocampus and pancreas of diabetic rats, and both N-acetylcysteine and deferoxamine reversed these alterations. Lipid damage was increased in the prefrontal cortex, hippocampus, amygdala and pancreas; however, treatment with N-acetylcysteine or deferoxamine reversed lipid damage only in the hippocampus and pancreas. Superoxide dismutase activity was decreased in the amygdala, nucleus accumbens and pancreas of diabetic rats. In diabetic rats, there was a decrease in catalase enzyme activity in the prefrontal cortex, amygdala, nucleus accumbens and pancreas, but an increase in the hippocampus. Treatment with antioxidants did not have an effect on the activity of antioxidant enzymes. In conclusion, animal model of diabetes produced depressive-like behaviour and oxidative stress in the brain and periphery. Treatment with antioxidants could be a viable alternative to treat behavioural and biochemical alterations induced by diabetes. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Self-reported Cognitive Biases Moderate the Associations Between Social Stress and Paranoid Ideation in a Virtual Reality Experimental Study.

    Science.gov (United States)

    Pot-Kolder, Roos; Veling, Wim; Counotte, Jacqueline; van der Gaag, Mark

    2017-10-10

    Cognitive biases are associated with psychosis liability and paranoid ideation. This study investigated the moderating relationship between pre-existing self-reported cognitive biases and the occurrence of paranoid ideation in response to different levels of social stress in a virtual reality environment. This study included 170 participants with different levels of psychosis liability (55 recent onset psychosis, 20 ultrahigh risk for psychosis, 42 siblings of psychotic patients, and 53 controls). All participants were exposed to virtual environments with different levels of social stress. The level of experienced paranoia in the virtual environments was measured with the State Social Paranoia Scale. Cognitive biases were assessed with a self-report continuous measure. Also, cumulative number of cognitive biases was calculated using dichotomous measures of the separate biases, based on general population norm scores. Higher belief inflexibility bias (Z = 2.83, P virtual environments. Level of paranoid response increased with number of cognitive biases present (B = 1.73, P < .001). The effect of environmental stressors on paranoid ideation was moderated by attention to threat bias (Z = 2.78, P < .01) and external attribution bias (Z = 2.75, P < .01), whereas data-gathering bias and belief inflexibility did not moderate the relationship. There is an additive effect of separate cognitive biases on paranoid response to social stress. The effect of social environmental stressors on paranoid ideation is further enhanced by attention to threat bias and external attribution bias.

  7. Chronic stress increases experimental pancreatic cancer growth, reduces survival and can be antagonised by beta-adrenergic receptor blockade.

    Science.gov (United States)

    Partecke, Lars Ivo; Speerforck, Sven; Käding, André; Seubert, Florian; Kühn, Sandra; Lorenz, Eric; Schwandke, Sebastian; Sendler, Matthias; Keßler, Wolfram; Trung, Dung Nguyen; Oswald, Stefan; Weiss, Frank Ulrich; Mayerle, Julia; Henkel, Christin; Menges, Pia; Beyer, Katharina; Lerch, Markus M; Heidecke, Claus-Dieter; von Bernstorff, Wolfram

    2016-01-01

    Chronic stress could promote tumour growth and reduce survival of pancreatic cancer patients via beta-adrenergic receptors of tumour cells. We have tested the impact of chronic acoustic and restraint stress on tumour development in an orthotopic syngeneic murine model of pancreatic cancer. Tumour-bearing C57BL/6 mice exposed to chronic stress had 45% (p = 0.0138) higher circulating steroid and 111% (p = 0.0052) higher adrenal tyrosine hydroxylase levels. Their immune response was significantly suppressed: The in vitro LPS response of splenocytes was significantly reduced regarding Th1- and Th2-cytokines including IFN-gamma, IL-6, IL-10 and MCP-1 (0.0011  0.05). TGF-beta in vitro was increased by 23.4% using catecholamines (p Beta-catecholamines increased proliferation in tumour cells by 18% (p beta-blocker propranolol reduced these effects by 25% (p beta-blockers of patients with pancreatic cancer or other malignancies should be further evaluated as an adjuvant anti-neoplastic agent in clinical trials. Copyright © 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  8. Oxidative stress and antioxidant enzymes activities in the African catfish, Clarias gariepinus, experimentally challenged with Escherichia coli and Vibrio fischeri.

    Science.gov (United States)

    Adeyemi, Joseph A

    2014-04-01

    The impacts of bacterial infection on cultivated fish species, African catfish, were investigated using oxidative stress biomarkers [lipid peroxidation (LPO) and protein carbonylation] and the activities of important antioxidant/detoxifying enzymes [catalase and glutathione S-transferase (GST)]. Fish were inoculated via oral gavage with one of the following treatments: 1 × 10(5) CFU/ml of Escherichia coli (EC1), 2 × 10(5) CFU/ml of E. coli (EC2), 1 × 10(5) CFU/ml of Vibrio fischeri (V1), 2 × 10(5) CFU/ml of V. fischeri (V2), gavaged with distilled water and not gavaged. Fish were maintained in the laboratory for 7 days after the bacterial inoculation, and the levels of LPO, protein carbonylation, GST, and catalase activities were determined in the muscle, gills, and liver of fish. Fish inoculated with bacteria (either E. coli or V. fischeri) had a significant higher levels of tissue LPO, protein carbonylation, and GST activities in a tissue-specific pattern (liver > muscle > gills). This appears to be related with the levels of bacterial inoculation, with effects more pronounced in fish inoculated with either EC2 or V2. The catalase activity did not differ significantly between the inoculated and fish that were not inoculated. The results of this study indicate that bacterial inoculation could result in oxidative stress in fish, and liver has a higher rate of oxidative stress per mg tissue compared to the gills and the muscle.

  9. Structure and mechanical properties of Cresco-Ti laser-welded joints and stress analyses using finite element models of fixed distal extension and fixed partial prosthetic designs.

    Science.gov (United States)

    Uysal, Hakan; Kurtoglu, Cem; Gurbuz, Riza; Tutuncu, Naki

    2005-03-01

    The Cresco-Ti System uses a laser-welded process that provides an efficient technique to achieve passive fit frameworks. However, mechanical behavior of the laser-welded joint under biomechanical stress factors has not been demonstrated. This study describes the effect of Cresco-Ti laser-welding conditions on the material properties of the welded specimen and analyzes stresses on the weld joint through 3-dimensional finite element models (3-D FEM) of implant-supported fixed dentures with cantilever extensions and fixed partial denture designs. Twenty Grade III (ASTM B348) commercially pure titanium specimens were machine-milled to the dimensions described in the EN10002-1 tensile test standard and divided into test (n = 10) and control (n = 10) groups. The test specimens were sectioned and laser-welded. All specimens were subjected to tensile testing to determine yield strength (YS), ultimate tensile strength (UTS), and percent elongation (PE). The Knoop micro-indentation test was performed to determine the hardness of all specimens. On welded specimens, the hardness test was performed at the welded surface. Data were analyzed with the Mann-Whitney U test and Student's t test (alpha=.05). Fracture surfaces were examined by scanning electron microscopy to characterize the mode of fracture and identify defects due to welding. Three-dimensional FEMs were created that simulated a fixed denture with cantilever extensions supported by 5 implants (M1) and a fixed partial denture supported by 2 implants (M2), 1 of which was angled 30 degrees mesio-axially. An oblique load of 400 N with 15 degrees lingual-axial inclinations was applied to both models at various locations. Test specimens fractured between the weld and the parent material. No porosities were observed on the fractured surfaces. Mean values for YS, UTS, PE, and Knoop hardness were 428 +/- 88 MPa, 574 +/- 113 MPa, 11.2 +/- 0.4%, 270 +/- 17 KHN, respectively, for the control group and 642 +/- 2 MPa, 772 +/- 72

  10. [An experimental model for assessing the risk factors for work-related stress in four Italian universities].

    Science.gov (United States)

    Miscetti, G; Barberini, L; Chiocchini, D; Cirimbilli, A; Pippi, R; Pampanella, L; Caserta, G; Gargarella, L

    2011-01-01

    This study, a collaborative effort among the Local Health Authority 2 of Perugia, Italy, the National Coordination of Worker's Safety Representatives for University and Research Institutions and the National Coordination for Protection and Prevention Services for Universities and Research Institutions, describes the results of a method used to evaluate work-related stress. Personnel from four Italian universities, which we call University I, II, III and IV geographically distributed in nord (1), center (2) and south (1) of Italy, responded to a questionnaire regarding risk evaluation of work-related stress in response to the Italian Law 81/2008. The methodology includes a preliminary analysis of the physical/technological and organizational/relational aspects of the company in order to determine a risk factor of work-related stress. This is followed by an evaluation by agencies competent in the areas of prevention and protection, (Administrative personnel of the company, Medical support persons, heads of the Prevention and Protection Service, employee representatives, and others) that apply a specific algorithm and by the employees through the completion of a questionnaire. The employees, mostly men, of the various universities, completed 510 questionnaires. Based on the results of the questionnaires and on a comparison between the expectations of the administration and the employees, the preventative measures that need to be adopted were identified. The results of this study show that there is not complete agreement between the administration and the employees regarding the work-related expectations. This difference in viewpoints could be a source of work-related stress. Some aspects of the study were shown to be of common concern in the various universities, while for other aspects, there were significantly different perceptions between male and female employees. An immediate response is needed with respect to some aspects in the work context and to plan further

  11. A study on the optimization of the angle of curvature for a Ranque-Hilsch vortex tube, using both experimental and full Reynolds stress turbulence numerical modelling

    Science.gov (United States)

    Rafiee, Seyed Ehsan; Ayenehpour, Sabah; Sadeghiazad, M. M.

    2016-02-01

    The working tube is a main part of vortex tube which the compressed fluid is injected into this part tangentially. An appropriate design of working tube geometry leads to better efficiency and performance of vortex tube. In the experimental investigation, the parameters are focused on the working tube angle, inlet pressure and number of nozzles. The effect of the working tube angle is investigated in the range of θ = 0-120°. The experimental tests show that we have an optimum model between θ = 0 and θ = 20°. The most objective of this investigation is the demonstration of the successful use of CFD in order to develop a design tool that can be utilized with confidence over a range of operating conditions and geometries, thereby providing a powerful tool that can be used to optimize vortex tube design as well as assess its utility in the field of new applications and industries. A computational fluid dynamics model was employed to predict the performances of the air flow inside the vortex tube. The numerical investigation was done by full 3D steady state CFD-simulation using FLUENT6.3.26. This model utilizes the Reynolds stress model to solve the flow equations. Experiments were also conducted to validate results obtained for the numerical simulation. First purpose of numerical study in this case was validation with experimental data to confirm these results and the second was the optimization of experimental model to achieve the highest efficiency.

  12. Oxidative stress and the effect of riboflavin supplementation in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-03-06

    Mar 6, 2009 ... The results show that there is oxidative stress in malaria infection and that chloroquine supplementation with riboflavin could ... quine treatment is reported to increase oxidative stress indices in experimental ... centrifuged (1500 g for 10 min) at room temperature for plasma and stored at -20°C until analysed ...

  13. Cultural, Transcriptomic, and Proteomic Analyses of Water-Stressed Cells of Actinobacterial Strains Isolated from Compost: Ecological Implications in the Fed-Batch Composting Process.

    Science.gov (United States)

    Narihiro, Takashi; Kanosue, Yuji; Hiraishi, Akira

    2016-06-25

    This study was undertaken to examine the effects of water activity (aw) on the viability of actinobacterial isolates from a fed-batch composting (FBC) process by comparing culturability and stainability with 5-cyano-2,3-ditoryl tetrazolium chloride (CTC). The FBC reactor as the source of these bacteria was operated with the daily loading of household biowaste for 70 d. During this period of composting, aw in the reactor decreased linearly with time and reached approximately 0.95 at the end of operation. The plate counts of aerobic chemoorganotrophic bacteria were 3.2-fold higher than CTC-positive (CTC+) counts on average at the fully acclimated stage (after 7 weeks of operation), in which Actinobacteria predominated, as shown by lipoquinone profiling and cultivation methods. When the actinobacterial isolates from the FBC process were grown under aw stress, no significant differences were observed in culturability among the cultures, whereas CTC stainability decreased with reductions in aw levels. A cDNA microarray-based transcriptomic analysis of a representative isolate showed that many of the genes involved in cellular metabolism and genetic information processing were down-regulated by aw stress. This result was fully supported by a proteomic analysis. The results of the present study suggest that, in low aw mature compost, the metabolic activity of the community with Actinobacteria predominating is temporarily reduced to a level that hardly reacts with CTC; however, these bacteria are easily recoverable by exposure to a high aw culture medium. This may be a plausible reason why acclimated FBC reactors in which Actinobacteria predominate yields higher plate counts than CTC+ counts.

  14. Aminoguanidina reduz o estresse oxidativo e as alterações estruturais pulmonares em diabetes mellitus experimental Aminoguanidine reduces oxidative stress and structural lung changes in experimental diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Fabio Cangeri Di Naso

    2010-08-01

    Full Text Available Avaliamos o efeito da aminoguanidina sobre o estresse oxidativo pulmonar e a estrutura pulmonar em um modelo experimental de diabetes mellitus. Foram determinados thiobarbituric acid reactive substances (TBARS, substâncias reativas ao ácido tiobarbitúrico, histologia e gasometria arterial em animais com diabetes mellitus (DM, animais com diabetes mellitus tratados com aminoguanidina (DM+AG e controles. O nível de TBARS foi significativamente maior no grupo DM que nos grupos controle e DM+AG (2,90 ± 1,12 vs. 1,62 ± 0,28 e 1,68 ± 0,04 nmol/mg proteína, respectivamente, o mesmo ocorrendo com PaCO2 em relação ao grupo controle (49,2 ± 1,65 vs. 38,12 ± 4,85 mmHg, e PaO2 foi significativamente maior no grupo controle (104,5 ± 6,3 vs. 69,48 ±16,30 e 97,05 ± 14,02 mmHg, respectivamente. Neste modelo experimental de diabetes mellitus, a aminoguanidina reduziu o estresse oxidativo, alterações estruturais teciduais pulmonares e a troca gasosa no modelo experimental.We evaluated the effect of aminoguanidine on pulmonary oxidative stress and lung structure in an experimental model of diabetes mellitus. Thiobarbituric acid reactive substances (TBARS, histology and arterial blood gases were evaluated in animals with diabetes mellitus (DM group, animals with diabetes mellitus treated with aminoguanidine (DM+AG group, and controls. The TBARS levels were significantly higher in the DM group than in the control and DM+AG groups (2.90 ± 1.12 vs. 1.62 ± 0.28 and 1.68 ± 0.04 nmol/mg protein, respectively, as was PaCO2 when compared with that of the control group (49.2 ± 1.65 vs. 38.12 ± 4.85 mmHg, and PaO2 was significantly higher in the control group (104.5 ± 6.3 vs. 16.30 ± 69.48 and 97.05±14.02 mmHg, respectively. In this experimental model of diabetes mellitus, aminoguanidine reduced oxidative stress, structural tissue alterations, and gas exchange.

  15. Experimental-numerical evaluation of a new butterfly specimen for fracture characterisation of AHSS in a wide range of stress states

    Science.gov (United States)

    Peshekhodov, I.; Jiang, S.; Vucetic, M.; Bouguecha, A.; Berhens, B.-A.

    2016-11-01

    Results of an experimental-numerical evaluation of a new butterfly specimen for fracture characterisation of AHHS sheets in a wide range of stress states are presented. The test on the new butterfly specimen is performed in a uniaxial tensile machine and provides sufficient data for calibration of common fracture models. In the first part, results of a numerical specimen evaluation are presented, which was performed with a material model of a dual-phase steel DP600 taken from literature with plastic flow and fracture descriptions. In the second part, results of an experimental-numerical specimen evaluation are shown, which was conducted on another dual-phase steel DP600, which was available with a description of plastic flow only and whose fracture behaviour was characterised in the frame of this work. The overall performance of the new butterfly specimen at different load cases with regard to characterisation of the fracture behaviour of AHSS was investigated. The dependency of the fracture strain on the stress triaxiality and Lode angle as well as space resolution is quantified. A parametrised CrachFEM ductile shear fracture model and modified Mohr-Coloumb ductile shear fracture model are presented as a result of this quantification. The test procedure and results analysis are believed to contribute to current discussions on requirements to AHSS fracture characterisation.

  16. Supporting of the Fathers to Visit Their Infants in Neonatal Intensive Care Unit Decreases Their Stress Level: A Pretest-Posttest Quasi-Experimental Study.

    Science.gov (United States)

    Kardaş Özdemir, Funda; Küçük Alemdar, Dilek

    2017-05-01

    It is known that fathers whose infants are hospitalized in NICUs (Neonatal Intensive Care Units) are severely stressed. This study was conducted for the purpose of determining the effect of supporting and visiting infants in NICUs on stress levels of Turkish fathers. This was a pretest-posttest quasi-experimental study. The population of the study consisted of 47 fathers who had their infants receiving treatment in NICU at a state hospital in the eastern Turkey and agreed to participate in the study. The data were collected by using "Father-Infant Introductory Information Form" and "Parental Stressor Scale: Neonatal Intensive Care Unit, PSS:NICU". When comparing the PSS:NICU total mean scores of the fathers before and after interventions; it was determined that their mean scores were higher before visits compared to those obtained after interventions and the difference between them was significant at advanced level. It was found that the fathers visiting and supporting their infants in NICUs had the decreased stress levels. It is a useful nursing intervention to support fathers to visit their babies in NICUs and establish environments where they could spend time with their babies.

  17. Evaluation of the safety of intracameral trypan blue injection on corneal tissue using oxidative stress parameters and apoptotic activity: an experimental study

    Directory of Open Access Journals (Sweden)

    Ali Akal

    2014-12-01

    Full Text Available Purpose: The present experimental study aimed to investigate the effects of intracameral trypan blue (TB on oxidative stress parameters and apoptosis in corneal tissue. Methods: Thirty rats were randomly assigned to three groups of 10 rats each: the sham group (Group 1; control group (Group 2; and treatment group (Group 3. The control group was administered 0.01 cc of balanced salt solution. The treatment group was administered 0.006 mg/0.01 cc of TB. The total antioxidant status (TAS and total oxidant status (TOS in corneal tissue and blood were measured and the oxidative stress index (OSI was calculated. Finally, corneal tissue histopathology was evaluated using staining for caspase-3 and -8, and apoptotic activity was examined. Results: The TAS, TOS and OSI levels in the blood samples were not significantly different (p>0.05 for all. Compared with the sham and control groups, the TOS and OSI levels in corneal tissue were significantly different in the treatment group (p0.05. Immunohistochemical staining for caspase-3 and caspase-8 demonstrated higher apoptotic activity in the TB group than in the sham and control groups. Conclusion: The present study showed that intracameral TB injection is safe systematically but may be toxic to corneal tissue, as demonstrated using oxidative stress parameters and histopathological evaluation.

  18. The effect of tobacco smoke on oxytocin concentrations and selected oxidative stress parameters in plasma during pregnancy and post-partum - an experimental model.

    Science.gov (United States)

    Napierala, M; Merritt, T A; Mazela, J; Jablecka, K; Miechowicz, I; Marszalek, A; Florek, E

    2017-02-01

    Tobacco smoking is a serious threat to life and health of society. Among the most vulnerable to the toxic effects of tobacco smoke are foetuses and newborns. The objective of the research was to assess the impact of tobacco smoke exposure on oxytocin levels and biochemical oxidative stress parameters during pregnancy and after birth in an experimental model. In the experiment, exposure to tobacco smoke of gravid and non-gravid rats was monitored. A reliable biomarker of exposure - cotinine - was used in the process and it was determined by means of high-performance liquid chromatography with diode array detection, which ensured high analytical accuracy and precision. Determination of oxytocin was performed by means of enzyme-linked immunosorbent assay. The levels of selected oxidative stress parameters: total protein concentration, uric acid, trolox equivalent antioxidant capacity, protein S-nitrosylation and lipid peroxidation (thiobarbituric acid reactive substances) were measured by spectrophotometric methods. The effect of prenatal and postnatal exposure to tobacco smoke was a lower medium body mass of rat foetuses and pups. Oxidative stress during pregnancy, additionally intensified by tobacco smoke exposure, led to adaptive changes in properties of plasmatic antioxidant barriers. Moreover, the disturbance of oxidoreductive balance by tobacco smoke affects oxytocin fluctuations, what was observed in this study during lactation period. Therefore, women who smoke may breastfeed their children less frequently and for a shorter period.

  19. Experimental variation of social stress in virtual reality - Feasibility and first results in patients with psychotic disorders.

    Science.gov (United States)

    Hesse, Klaus; Schroeder, Philipp A; Scheeff, Jonathan; Klingberg, Stefan; Plewnia, Christian

    2017-09-01

    Social interaction might lead to increased stress levels in patients with psychotic disorders. Impaired social stress tolerance is critical for social functioning and closely linked with symptom relapse and hospitalization. We present an interactive office built-up in virtual reality (VR). Patients with psychotic disorders (PP, N = 26 including N = 5 dropouts) and matched healthy controls (HC, N = 20) were examined with a VR simulating an open-plan office. In a randomized, controlled cross-over design, participants were introduced to virtual co-workers (avatars) and requested to ask them for task assistance. Social feedback in each of the two sessions was either cooperative or rejective in randomized order. The office environment was tolerable for most PP and all HC, five PP and none of the HC dropped out for any reason. Drop-outs reported simulator sickness, influence on thoughts and symptom exacerbations. Statistical trends indicated heightened paranoid ideations for PP after social rejection. State measures of paranoid ideations showed high convergent validity with conventional measures of delusions. Of note, measures of presence were higher for PP than for HC. The exploratory design limits the robustness of the findings. Only statistical trends on paranoid ideation were found. The use of VR to assess the effects of social rejection is feasible and tolerable for most PP (87%). However, its implementation for PP is challenged by increased simulator sickness and an additional stress load for some patients. Further studies continuing on these first results that point towards an increased paranoid ideation evoked by negative social feedback and generally higher subjective presence are needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Role of Oxidative Stress in the Development of Cardiac Depression in Severe Isolated Brain Injury (Experimental Study

    Directory of Open Access Journals (Sweden)

    V. V. Rusakov

    2009-01-01

    Full Text Available Objective: to study the role of oxidative stress in the development of cardiac structural and metabolic disorders in severe isolated brain injury (BI. Materials and methods. The impact of BI on the parameters of serum chemilu-minescence and the contractility of isolated rat hearts were studied in experiments on 66 outbred male albino rats, as described by E. T. Fallen et al. Lipid peroxidation processes were inhibited, by intraperitoneally injecting the antioxidant carnosine (100 mg/kg 1 and 24 hours before or just after BI. Results. The rate of free radical processes rose an hour after severe isolated BI, which was associated with the indirect signs of cardiomyocitic membrane damages, depressed rat heart contractility, and their diminished resistance to hypoxia, reoxygenation, and exercise by high rhythm. Administration of carnosine to the animals favored the normalization of chemluminescent values with the high overall antioxidative capacity of serum. The effect of the agent depended on the time of its use and it was high when carnosine was injected 1 and 24 hours before injury. At the stage of reoxygenation after the hypoxic test, there was a significant increase in evolving pressure, the rate of left ventricular myocardial contraction and relaxation, and a reduction in AsAT activity in all coronary duct tests, as compared with the controls. A negative correlation was found between the burst amplitude and the myocardial relaxation rate in the animals receiving the agent. Conclusion. Improved cardiac contractility and increased capacities of the mechanisms responsible for Ca2+ transport due to the use of the antioxidant carnosine allow one to state that oxidative stress is one of the pathogenetic factors of cardiac depression in severe isolated BI. Key words: brain injury, heart, oxidative stress, carnosine.

  1. Experimental Study of Pressure Drop and Wall Shear Stress Characteristics of γ /Al2O3-Water Nanofluid in a Circular pipe under Turbulent flow induced vibration.

    Directory of Open Access Journals (Sweden)

    Adil Abbas AL-Moosawy

    2016-09-01

    Full Text Available Experimental study of γ /Al2O3 with mean diameter of less than 50 nm was dispersed in the distilled water that flows through a pipe consist of five sections as work station ,four sections made of carbon steel metal and one sections made of Pyrex glass pipe, with five nanoparticles volume concentrations of 0%,0.1%,0.2%,0.3%,and 0.4% with seven different volume flow rates 100, 200 , 300, 400, 500, 600 ,and 700ℓ/min were investigated to calculated pressure distribution for the cases without rubber ,with 3mm rubber and with 6mm rubber used to support the pipe. Reynolds number was between 20000 and 130000. Frequency value through pipe was measured for all stations of pipe for all cases. The results show that the pressure drop and wall shear stress of the nanofluid increase by increasing the nanoparticles volume concentrations or Reynolds number, the values of frequency through the pipe increase continuously when wall shear stress increases and the ratio of increment increases as nanofluid concentrations increase. Increasing of vibration frequency lead to increasing the friction factor between the pipe and the wall and thus increasing in pressure drop. Several equations between the wall shear stress and frequency for all volume concentration and for three cases without rubber, with rubber has 3mm thickness ,and with rubber has 6mm thickness. Finally, the results led to that γ /Al2O3 could function as a good and alternative conventional working fluid in heat transfer applications. A good agreement is seen between the experimental and those available in the literature

  2. Combined analysis of stress myocardial tomo-scintigraphies and coronaries angio scanners to identify the arteries responsible of ischemia;Analyse combinee des tomoscintigraphies myocardiques de stress et angioscanners coronaires pour identifier les arteres responsables de l'ischemie

    Energy Technology Data Exchange (ETDEWEB)

    Didot, N.; Djaballah, W.; Daragon, N.; Gillet, N.; Meneroux, B.; Netter, F.; Paris-Grandpierre, S.; Karcher, G.; Marie, P.Y. [CHU de Nancy-Brabois, Service de medecine nucleaire, 54 (France); Mandry, D. [CHU de Nancy-Brabois, Service de radiologie, 54 (France)

    2010-05-15

    The purpose of this study is to assess the contribution of an analysis by image fusion of myocardium tomo-scintigraphy and coronary angio scanner in the identification of coronary artery responsible for myocardial ischemia stress. As results, the identification in myocardium tomo-scintigraphy of the ischemic arterial trunk is rarely changed by a combined analysis with coronary angio scanner. Discrepancies between the two examinations are common, even after fusion, but especially for mild ischemia. (N.C.)

  3. Experimental Study on Wing Crack Behaviours in Dynamic-Static Superimposed Stress Field Using Caustics and High-Speed Photography

    Directory of Open Access Journals (Sweden)

    L.Y. Yang

    2014-07-01

    Full Text Available During the drill-and-blast progress in rock tunnel excavation of great deep mine, rock fracture is evaluated by both blasting load and pre-exiting earth stress (pre-compression. Many pre-existing flaws in the rock mass, like micro-crack, also seriously affect the rock fracture pattern. Under blasting load with pre-compression, micro-cracks initiate, propagate and grow to be wing cracks. With an autonomous design of static-dynamic loading system, dynamic and static loads were applied on some PMMA plate specimen with pre-existing crack, and the behaviour of the wing crack was tested by caustics corroding with a high-speed photography. Four programs with different static loading modes that generate different pre-compression fields were executed, and the length, velocity of the blasting wing crack and dynamic stress intensity factor (SIF at the wing crack tip were analyzed and discussed. It is found that the behaviour of blasting-induced wing crack is affected obviously by blasting and pre-compression. And pre-compression, which is vertical to the direction of the wing crack propagation, hinders the crack propagation. Furthermore, the boundary constraint condition plays an important role on the behaviour of blasting induced crack during the experiment.

  4. Effects of gamma oryzanol on factors of oxidative stress and sepsis-induced lung injury in experimental animal model

    Directory of Open Access Journals (Sweden)

    Elmira Zolali

    2015-12-01

    Full Text Available Objective (s: There is corroborating evidence to substantiate redox imbalance and oxidative stress in sepsis that finally leads to organ damage or even death. Gamma oryzanol (GO is one of the major bioactive components in rice bran has been considered to function as an antioxidant. The present study was carried out to evaluate the antioxidant activity of gamma oryzanol in vitro and its efficacy in sepsis. Materials and Methods: To induce sepsis, cecal ligation and puncture (CLP method was performed on the rats. A study group of forty male Wistar rats were divided into the following groups: sham group; CLP group; 50 mg/kg GO- treated CLP group and 100 mg/kg GO- treated CLP group. GO was administered with an oral gavage 2 hr prior to inducing sepsis. Tissue and blood samples were collected 12 hr after CLP to prepare tissue sections for histopathological study and assay the oxidative stress biomarkers including: SOD (Superoxide Dismutase, TAC (total antioxidant capacity, MDA (Malondialdehyde, MPO (Myeloperoxidase and PAI-1 (Plasminogen Activator Inhibitor-1. Data are given as mean ± SD. The ANOVA with Tukey post hoc test was used to determine the differences between groups and P Results: TAC level increased in GO- treated CLP groups (P

  5. Experimental study of anisotropic stress/strain relationships of the piglet great vessels and relevance to pediatric congenital heart disease.

    Science.gov (United States)

    Jia, Yueqian; Argueta-Morales, I Ricardo; Liu, Miao; Bai, Yuanli; Divo, Eduardo; Kassab, Alain J; DeCampli, William M

    2015-04-01

    Determining material mechanical properties of neonatal aorta and pulmonary artery will aid understanding tissue behavior when subjected to abnormal hemodynamics of congenital heart disease. Aorta and pulmonary arteries were harvested from 6 neonatal piglets (mean weight 3.5 kg). Tissue samples from ventral and dorsal aspects of ascending aorta (AA) and descending aorta (DA), innominate artery (IA), left subclavian artery (LScA), main pulmonary artery (MPA), and left pulmonary artery (LPA) and right pulmonary artery (RPA) were obtained in three orientations: circumferential, diagonal, and longitudinal. Samples were subjected to uniaxial tensile testing. True strain-Cauchy stress curves were individually fitted for each orientation to calibrate the Fung model, and to measure tissue stiffness (10% strain). All samples, for all orientations, demonstrated nonlinear hyperelastic strain-stress response to uniaxial tensile testing (Holzapfel-Gasser and fitted-Fung models R(2) > 0.95). For each vessel segment, stiffness was not significantly different among orientations. Stiffness values in all orientations, including ventral/dorsal samples, were compared between AA > MPA (p = 0.08), DA > MPA (p AA (p = 0.35). Comparison of circumferential orientation samples showed AA and DA are significantly stiffer than MPA (p congenital heard disease. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Comparison of the energetic stress associated with experimental Nosema ceranae and Nosema apis infection of honeybees (Apis mellifera).

    Science.gov (United States)

    Martín-Hernández, Raquel; Botías, Cristina; Barrios, Laura; Martínez-Salvador, Amparo; Meana, Aránzazu; Mayack, Christopher; Higes, Mariano

    2011-09-01

    Nosema ceranae is a relatively new and widespread parasite of the western honeybee Apis mellifera that provokes a new form of nosemosis. In comparison to Nosema apis, which has been infecting the honeybee for much longer, N. ceranae seems to have co-evolved less with this host, causing a more virulent disease. Given that N. apis and N. ceranae are obligate intracellular microsporidian parasites, needing host energy to reproduce, energetic stress may be an important factor contributing to the increased virulence observed. Through feeding experiments on caged bees, we show that both mortality and sugar syrup consumption were higher in N. ceranae-infected bees than in N. apis-infected and control bees. The mortality and sugar syrup consumption are also higher in N. apis-infected bees than in controls, but are less than in N. ceranae-infected bees. With both microsporidia, mortality and sugar syrup consumption increased in function of the increasing spore counts administered for infection. The differences in energetic requirements between both Nosema spp. confirm that their metabolic patterns are not the same, which may depend critically on host-parasite interactions and, ultimately, on host pathology. The repercussions of this increased energetic stress may even explain the changes in host behavior due to starvation, lack of thermoregulatory capacity, or higher rates of trophallaxis, which might enhance transmission and bee death.

  7. The effect of melatonin on oxidative stress and apoptosis in experimental diabetes mellitus-related ovarian injury.

    Science.gov (United States)

    Nayki, Umit; Onk, Didem; Balci, Gurhan; Nayki, Cenk; Onk, Alper; Çankaya, Murat; Taskın Kafa, Ayse Humeyra; Kuzucu, Mehmet

    2016-01-01

    We aimed to evaluate the effect of melatonin on oxidative stress and ovarian injury in rats. Twenty-four Sprague-Dawley albino rats were divided into three groups: Group 1 as nondiabetic healthy controls (n = 8), group 2 as nontreated diabetic rats (n = 8) and group 3 as melatonin-treated diabetic rats (n = 8). After overt diabetes was produced by intraperitoneal injection of streptozosin, 20 mg/kg/day of melatonin was given intraperitoneally to group 3 for a week. NF-kB and caspase-3 immunoexpressions, lipid peroxidation, the activities of antioxidative enzymes, total oxidant capacity and total antioxidant capacity were assessed. Immunoexpressions of NF-kB and caspase-3 were significantly lower in group 3 than group 2. There was a significant decrease in superoxide dismutase activity in group 2 than group 1 and a significant increase in group 3 compared with group 2. We observed a nonsignificant decrease in catalase activity between group 1 and group 2 and a nonsignificant increase between group 2 and group 3. There was a nonsignificant increase in the plasma level of total oxidant status in group 2 than group 1, but a significant decrease was observed in group 3 compared to group 2. Total antioxidant status was significantly lower in group 2 compared with group 1 and group 3. In conclusion, melatonin ameliorates the negative effects of oxidative stress on DM-related ovarian injury.

  8. Resveratrol protects against experimental induced Reye's syndrome by prohibition of oxidative stress and restoration of complex I activity.

    Science.gov (United States)

    Abdin, Amany; Sarhan, Naglaa

    2014-09-01

    This study was designed to investigate whether resveratrol could provide protection against Reye's syndrome induced by 4-pentenoic acid in Wistar albino rats. Compared with rats with untreated Reye's syndrome, 1 h pretreatment by low dose resveratrol (10 mg/kg by oral gavage) resulted in marked amelioration in liver functions in the form of significant decrease in serum transaminases (AST, ALT) and plasma ammonia levels, shortening of prothrombin time, and increase in serum albumin levels. In addition, resveratrol prohibited oxidative stress markers, as indicated by a significant increase in GSH and decrease in MDA, with restoration of complex I activity in liver tissues. The classical histopathological presentation in Reye's syndrome of microvesicular steatosis by light microscope and mitochondria distortion by electron microscope has been improved by resveratrol pretreatment. The efficient protection by resveratrol was determined by normalization in serum levels of AST and albumin, as well as complex I activity, GSH, and MDA. In conclusion, pretreatment by resveratrol in low doses could protect against Reye's syndrome partially via prohibition of oxidative stress and restoration of complex I activity. This may provide the opportunity to reconsider aspirin therapy for infants and young children. However, the verification of such results in clinical practice remains a challenge.

  9. Experimental study on the Reynolds and viscous shear stress of bileaflet mechanical heart valves in a pneumatic ventricular assist device.

    Science.gov (United States)

    Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2009-01-01

    Our group is currently developing a pneumatic ventricular assist device (PVAD). In general, the major causes of hemolysis in a pulsatile VAD are cavitation, and Reynolds shear stress (RSS) in the mechanical heart valve (MHV). In a previous study, we investigated MHV cavitation. To select the optimal bileaflet valve for our PVAD, in the current study, we investigated RSS and viscous shear stress (VSS) downstream of three different types of commercial bileaflet valves by means of 2D particle image velocimetry (PIV). To carry out flow visualization inside the blood pump and near the valve, we designed a model pump with the same configuration as that of our PVAD. Three types of bileaflet valves (i.e., the ATS valve, the St. Jude valve, and the Sorin Bicarbon valve) were mounted at the aortic position of the model pump, and flow was visualized according to the PIV method. The maximum flow velocity and RSS of the Sorin Bicarbon valve were lower than those of the other two bileaflet valves. The maximum VSS was only 1% of the maximum RSS. Thus, the effect of VSS on blood cell trauma was neglected. The Sorin Bicarbon valve exhibited relatively low levels of RSS, and was therefore considered to be the best valve for our PVAD among the three valves tested.

  10. Learning in artistic gymnastics. An experimental study with children analysing some variables in that process Aprendizaje en gimnasia artística. Un estudio experimental con niños que analiza ciertas variables del proceso

    Directory of Open Access Journals (Sweden)

    J. López

    2010-09-01

    Full Text Available

    Today the training of sports skills has lead to the conception of new approaches to attain maximum results. In practice, many teaching methods are used, yet most of the articles on motor learning or sports training refer to the total or global and the partial or analytic methods, both of interest in the field of gymnastics, offering a number of important combinations between either extreme.

    Opinions differ concerning effectiveness, and such differences also exist in gymnastics. Carrasco (1977, nevertheless, proposes "mini-circuits" as the ideal teaching method in gymnastics. In looking for a practical solution to global or analytical teaching, one experimental group study was undertaken with children participating in Sports Schools between the ages of 9 and 11. The aim was to compare the effect of three training sessions (analytical training, "mini-circuit" training, mixed training on the learning and recall of gymnastic skills.

    Interested in both final performance as well as the teaching process, the following variables were studied: motor activity time, waiting time, total number of global movements, total number of feedbacks emitted by the teacher (amount and direction, and total number of spot checks. A pre-test, post-test and re- test design was used with three groups to assess the three training sessions. Each group was trained to learn the same variable-dependent outcome.

    The results of the study showed that the "mini-circuit" training was the most effective learning and recall method. The most highly-influence process variables were both the type of aids and type of feedback provided. Overall, it is worth highlighting the importance of using the "mini-circuit" method with children. From a pedagogic perspective, this is an important finding to take into consideration, which could yield important results during schooling.
    KEY WORDS

  11. A cohort study of toner-handling workers on inflammatory, allergic, and oxidative stress markers: cross-sectional and longitudinal analyses from 2003 to 2008.

    Science.gov (United States)

    Kitamura, H; Terunuma, N; Kurosaki, S; Hata, K; Masuda, M; Kochi, T; Yanagi, N; Murase, T; Ogami, A; Higashi, T

    2015-04-01

    This study examines the relationship between toner exposure and its health effects in terms of biomarkers which are known to assess the damages to humans caused by toxic material exposure. The subjects were 1504 male workers aged below 50 in 2003 in a Japanese toner and photocopier manufacturing company. Personal exposure measurements, pulmonary function tests, chest X-ray examinations, biomarker measurement, and a questionnaire about respiratory symptoms were conducted. We will report about biomarker measurement in this study. Cross-sectional survey studies and a longitudinal study from 2003 to 2008 were conducted. Few significant findings were associated with the toner exposure in both the cross-sectional and the longitudinal studies. The higher toner exposure concentrations did not induce effects on increasing biomarkers. There was no evidence of excessive inflammatory, allergic, or oxidative stress reaction in toner-handling workers as compared to non-handling workers, despite some sporadically significant findings. There are no other reports of a longitudinal epidemiological study with regard to toner exposure; this report significantly contributes to toner exposure literature. Although in the current well-controlled working environment, the toner exposure concentrations are quite low; further studies are needed to completely understand the health effects toner may have, however small they may be. © The Author(s) 2014.

  12. SWATH label-free proteomics analyses revealed the roles of oxidative stress and antioxidant defensing system in sclerotia formation of Polyporus umbellatus

    Science.gov (United States)

    Li, Bing; Tian, Xiaofang; Wang, Chunlan; Zeng, Xu; Xing, Yongmei; Ling, Hong; Yin, Wanqiang; Tian, Lixia; Meng, Zhixia; Zhang, Jihui; Guo, Shunxing

    2017-01-01

    Understanding the initiation and maturing mechanisms is important for rational manipulating sclerotia differentiation and growth from hypha of Polyporus umbellatus. Proteomes in P. umbellatus sclerotia and hyphae at initial, developmental and mature phases were studied. 1391 proteins were identified by nano-liquid chromatograph-mass spectrometry (LC-MS) in Data Dependant Acquisition mode, and 1234 proteins were quantified successfully by Sequential Window Acquisition of all THeoretical fragment ion spectra-MS (SWATH-MS) technology. There were 347 differentially expressed proteins (DEPs) in sclerotia at initial phase compared with those in hypha, and the DEP profiles were dynamically changing with sclerotia growth. Oxidative stress (OS) in sclerotia at initial phase was indicated by the repressed proteins of respiratory chain, tricarboxylic acid cycle and the activation of glycolysis/gluconeogenesis pathways were determined based on DEPs. The impact of glycolysis/gluconeogenesis on sclerotium induction was further verified by glycerol addition assays, in which 5% glycerol significantly increased sclerotial differentiation rate and biomass. It can be speculated that OS played essential roles in triggering sclerotia differentiation from hypha of P. umbellatus, whereas antioxidant activity associated with glycolysis is critical for sclerotia growth. These findings reveal a mechanism for sclerotial differentiation in P. umbellatus, which may also be applicable for other fungi.

  13. Being deluded after being excluded? How emotion regulation deficits in paranoia-prone individuals affect state paranoia during experimentally induced social stress.

    Science.gov (United States)

    Westermann, Stefan; Kesting, Marie-Luise; Lincoln, Tania M

    2012-06-01

    Emotion regulation (ER) has become a relevant construct to understanding paranoia. While the ER strategy called expressive suppression (e.g., poker face) may foster state paranoia by increasing arousal, another strategy called reappraisal (e.g., changing the perspective on situations) may reduce negative emotions and state paranoia when adaptively used. However, if reappraisal fails, this could increase paranoia. The aim of this study was to test the proposed effects of the ER strategies on state paranoia in the socially stressful situation of being excluded in paranoia-prone individuals. We conducted an experimental online study with N=116 participants who were randomized to a social inclusion or an exclusion condition using a virtual Cyberball ball-tossing game. They completed questionnaires on paranoia proneness and habitual ER strategies. Before and after the Cyberball task, participants rated their level of state paranoia. The impact of habitual ER strategies, paranoia proneness, and social stress on changes in state paranoia was investigated using linear regression analysis. The three-way interaction of social stress, paranoia proneness, and habitual reappraisal use significantly predicted state paranoia, t(114)=2.62, p=0.010. The decomposition of the interaction term revealed that in the social stress condition, the impact of reappraisal on state paranoia was moderated by the level paranoia proneness. Specifically, in high paranoia-prone individuals the use of reappraisal predicted higher state paranoia. The findings regarding habitual use of suppression were not significant. Although reappraisal is generally considered a functional strategy, its use in distressing social situations seems to be impaired in persons with higher paranoia proneness. A working model of emotion dysregulation in delusions is presented and possible implications for cognitive therapy of psychosis are discussed. Copyright © 2011. Published by Elsevier Ltd.

  14. Enhancing the adaptability of the deep-sea bacterium Shewanella piezotolerans WP3 to high pressure and low temperature by experimental evolution under H2O2 stress.

    Science.gov (United States)

    Xie, Zhe; Jian, Huahua; Jin, Zheng; Xiao, Xiang

    2017-12-21

    The oxidative stresses commonly exist in natural environments and microbes have developed variety of defensive systems to counteract such events. Although increasing evidence has shown that high-hydrostatic pressure (HHP) and low temperature (LT) induce the antioxidant defense responses in cells, there is no direct evidence to prove the connection between antioxidant defense mechanism and adaptation of bacteria to HHP/LT. In this study, using the wild-type strain (WT) of a deep-sea bacterium Shewanella piezotolerans WP3 as an ancestor, we obtained a mutant, OE100, with enhanced antioxidant defense capacity by experimental evolution under H2O2 stress. Notably, OE100 exhibited better tolerance not only to H2O2 stress but also to HHP/LT (20 MPa/4°C). Whole-genome sequencing identified deletion mutation in the gene oxyR, which encodes the transcription factor that controls oxidative stress response. Comparative transcriptome analysis showed that the genes associated with oxidative stress defense, anaerobic respiration, DNA repair, flagella and bacteriophage synthesis were differentially expressed in OE100 compared with the WT at 20 MPa/4°C. Genetic analysis of oxyR and ccpA2 indicated the OxyR-regulated cytochrome c peroxidase CcpA2 significantly contributed to the adaptation of WP3 to HHP/LT. Taken together, these results confirmed the inherent relationship between antioxidant defense mechanism and HHP/LT adaptation in benthic microorganism.IMPORTANCE The oxidative stress exists in various niches including the deep-sea ecosystem, which is an extreme environment with conditions of HHP, and predominantly LT. Although previous studies have shown that HHP and LT induce antioxidant defense response in cells, the direct evidence to prove the connection between antioxidant defense mechanism and adaptation of bacteria to HHP/LT is lacking. In this work, using the deep-sea bacterium Shewanella piezotolerans WP3 as a model, we proved that enhancement of the adaptability of WP

  15. Comparative analyses of genotype dependent expressed sequence tags and stress-responsive transcriptome of chickpea wilt illustrate predicted and unexpected genes and novel regulators of plant immunity

    Directory of Open Access Journals (Sweden)

    Chakraborty Niranjan

    2009-09-01

    Full Text Available Abstract Background The ultimate phenome of any organism is modulated by regulated transcription of many genes. Characterization of genetic makeup is thus crucial for understanding the molecular basis of phenotypic diversity, evolution and response to intra- and extra-cellular stimuli. Chickpea is the world's third most important food legume grown in over 40 countries representing all the continents. Despite its importance in plant evolution, role in human nutrition and stress adaptation, very little ESTs and differential transcriptome data is available, let alone genotype-specific gene signatures. Present study focuses on Fusarium wilt responsive gene expression in chickpea. Results We report 6272 gene sequences of immune-response pathway that would provide genotype-dependent spatial information on the presence and relative abundance of each gene. The sequence assembly led to the identification of a CaUnigene set of 2013 transcripts comprising of 973 contigs and 1040 singletons, two-third of which represent new chickpea genes hitherto undiscovered. We identified 209 gene families and 262 genotype-specific SNPs. Further, several novel transcription regulators were identified indicating their possible role in immune response. The transcriptomic analysis revealed 649 non-cannonical genes besides many unexpected candidates with known biochemical functions, which have never been associated with pathostress-responsive transcriptome. Conclusion Our study establishes a comprehensive catalogue of the immune-responsive root transcriptome with insight into their identity and function. The development, detailed analysis of CaEST datasets and global gene expression by microarray provide new insight into the commonality and diversity of organ-specific immune-responsive transcript signatures and their regulated expression shaping the species specificity at genotype level. This is the first report on differential transcriptome of an unsequenced genome during

  16. Comparative analyses of genotype dependent expressed sequence tags and stress-responsive transcriptome of chickpea wilt illustrate predicted and unexpected genes and novel regulators of plant immunity.

    Science.gov (United States)

    Ashraf, Nasheeman; Ghai, Deepali; Barman, Pranjan; Basu, Swaraj; Gangisetty, Nagaraju; Mandal, Mihir K; Chakraborty, Niranjan; Datta, Asis; Chakraborty, Subhra

    2009-09-05

    The ultimate phenome of any organism is modulated by regulated transcription of many genes. Characterization of genetic makeup is thus crucial for understanding the molecular basis of phenotypic diversity, evolution and response to intra- and extra-cellular stimuli. Chickpea is the world's third most important food legume grown in over 40 countries representing all the continents. Despite its importance in plant evolution, role in human nutrition and stress adaptation, very little ESTs and differential transcriptome data is available, let alone genotype-specific gene signatures. Present study focuses on Fusarium wilt responsive gene expression in chickpea. We report 6272 gene sequences of immune-response pathway that would provide genotype-dependent spatial information on the presence and relative abundance of each gene. The sequence assembly led to the identification of a CaUnigene set of 2013 transcripts comprising of 973 contigs and 1040 singletons, two-third of which represent new chickpea genes hitherto undiscovered. We identified 209 gene families and 262 genotype-specific SNPs. Further, several novel transcription regulators were identified indicating their possible role in immune response. The transcriptomic analysis revealed 649 non-cannonical genes besides many unexpected candidates with known biochemical functions, which have never been associated with pathostress-responsive transcriptome. Our study establishes a comprehensive catalogue of the immune-responsive root transcriptome with insight into their identity and function. The development, detailed analysis of CaEST datasets and global gene expression by microarray provide new insight into the commonality and diversity of organ-specific immune-responsive transcript signatures and their regulated expression shaping the species specificity at genotype level. This is the first report on differential transcriptome of an unsequenced genome during vascular wilt.

  17. Pioglitazone, a PPARγ agonist rescues depression associated with obesity using chronic unpredictable mild stress model in experimental mice

    Directory of Open Access Journals (Sweden)

    Yeshwant Kurhe

    2016-06-01

    Full Text Available Pioglitazone, a peroxisome proliferator activated receptor gamma (PPARγ agonist belonging to thiazolidinedione class, is mainly used in diabetes mellitus. Obese subjects are twice likely to become depressed than non-obese individuals. The biological mechanisms linking depression with obesity still remain poorly understood and there is immense need for better therapeutic intervention against such co-morbid disorders. The present study investigates the effect of pioglitazone on the chronic unpredictable mild stress (CUMS induced depression in obese mice by using behavioral tests and biochemical estimations. Mice were fed with high fat diet (HFD for 14 weeks and were further subjected to different stress procedures for 28 days to induce depressive behavior. Animals were administered orally with pioglitazone (30 mg/kg p.o./escitalopram (10 mg/kg p.o./vehicle (10 ml/kg p.o. daily from day 15–28. Various behavioral paradigms such as sucrose preference test, forced swim test (FST, tail suspension test (TST and elevated plus maze (EPM were performed. Biochemical estimations including plasma glucose, total cholesterol, triglycerides, and total proteins were performed. The data obtained from behavioral assays and biochemical assessments indicated that obese animals exhibited severe depressive-like behavior compared to non-obese animals. Furthermore, obese animals subjected to CUMS worsen the depressive behavior compared to obese control animals. Repetitive treatment with pioglitazone reversed the CUMS induced behavioral and biochemical alterations in HFD fed obese mice which atleast in part may be mediated through improving altered plasma glucose. The study suggests that pioglitazone needs further attention with respect to molecular mechanisms that could provide a better therapeutic strategy against depression associated with obesity.

  18. Experimental Determination and Numerical Modelling of Process Induced Strains and Residual Stresses in Thick Glass/Epoxy Laminate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Hattel, Jesper Henri; Løgstrup Andersen, Tom

    2012-01-01

    In this work, a cure hardening instantaneous linear elastic (CHILE) model and a path dependent (PD) constitutive approach are compared, for the case of modelling strain build-up during curing of a thick composite laminate part. The PD approach is a limiting case of viscoelasticity with path...... dependency on temperature and cure degree. Model predictions are compared to experimentally determined in-situ strains, determined using FBG sensors. It was found that both models offer good approximations of internal strain build-up. A general shortcoming is the lack of capturing rate-dependent effects...

  19. [The experimental study on melatonin gastro intestinal motility and plasma levels of stress hormones in overtraining rat].

    Science.gov (United States)

    Jing, Hui-feng; Wang, Xiao-mei

    2015-09-01

    To study the effect of melatonin on the gastrointestinal motility and plasma levels of the stress hormone in overtraining rats. Thirty adult SD rats were randomly divided into three groups (n = 10): control group, over-training group, melatonin intervention group. 30 min before each training, rats in the control and over-training groups were fed with normal saline (15 mg/kg) once a day and 5 times per week, while rats in the melatonin intervention group were administrated with melatonin, perfusion in the intervention group (15 mg/kg). Excessive training group and melatonin intervention group rats were subjected to excessive training at 5 times a week for 6 weeks. After 6 weeks, the gastric emptying rate, small intestinal propulsion ratio and levels of plasma motilin (MTL) and calcitonin gene-related peptide (CGRP), cortisol (CORT) and catecholamines (CA) were observed in all groups. Compared with the control group, the gastric emptying rate, small intestinal propulsion ratio and levels of plasma MTL, CORT and CA were increased significantly (P melatonin, this trend was reversed, that was, the gastric emptying rate, small intestinal propulsion ratio and levels of plasma MTL, CORT and CA were surpressed significantly (P Melatonin plays an important role in protecting gastrointestinal tract from dysfunction, in which MTL, CGRP, CORT and CA are all involved.

  20. Caffeine intake decreases oxidative stress and inflammatory biomarkers in experimental liver diseases induced by thioacetamide: Biochemical and histological study.

    Science.gov (United States)

    Amer, Mona G; Mazen, Nehad F; Mohamed, Ahmed M

    2017-03-01

    Liver disease remains a significant global health problem. Increased caffeine consumption has been associated with a lower prevalence of chronic liver disease. This study aimed to investigate the modifying effects of caffeine on liver injury induced by thioacetamide (TAA) administration in male rats and the possible underlying mechanisms. Forty adult male rats were equally classified into four groups: control group, received only tap water; caffeine-treated group, received caffeine (37.5 mg/kg per day); TAA-treated group, received intraperitoneal (i.p.) TAA (200 mg/kg b.w.) twice a week; and caffeine + TAA-treated group, received combined TAA and caffeine in the same previous doses. After eight weeks of treatment, blood samples were collected for biochemical analysis and liver specimens were prepared for histological and immunohistochemical studies and for assessment of oxidative stress. TAA induced liver toxicity with elevated liver enzymes and histological alterations, fatty changes, apoptosis, and fibrosis evidenced by increased immunohistochemical reaction to matrix metalloproteinase-9 (MMP-9) and collagen type IV in hepatocytes. Also, the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in serum were significantly elevated. Co-treatment with caffeine and TAA restored normal liver structure and function. Caffeine provided an anti-fibrogenic, anti-inflammatory, and antioxidant effect that was associated with recovery of hepatic histological and functional alterations from TAA-induced hepatotoxicity.

  1. Numerical and experimental analysis of the residual stress field in cladded components; Numerische und experimentelle Bestimmung des Eigenspannungszustands in plattierten Komponenten

    Energy Technology Data Exchange (ETDEWEB)

    Siegele, Dieter; Brand, Marcus; Hohe, Joerg [Fraunhofer Inst. fuer Werkstoffmechanik, Freiburg (Germany)

    2008-07-01

    The inner surface of a ferritic reactor pressure vessel is protected against corrosion by an austenitic cladding that is usually performed by a double-pass welding in order to avoid under-clad defects und to improve the microstructural properties of the cladding material. On the other hand the different thermal expansion coefficients of the cladding and the base metal induce a complex residual stress field. This has a non-negligible influence on the fracture mechanical assessment of postulated flaws within or under the cladding. The determination of the residual stress field was achieved by numerical simulation of the cladding process. The calibration of the used equivalent heat sources for the modelling of the heat input within the simulation was performed using measured data of the temperature field in a KTA compliant cladding process of test plates made of plant-representative materials. The simulation of the welding process used the temperature dependent material characteristics taking into account the transformation behaviour of the ferritic base metal. The resulting residual stress field shows significant tensile stresses within the cladding with a subsequent compressive stress field under the cladding. The calculated residual stress field is in good agreement with the experimental data. A comparison of the calculated residual stress field using the process simulation with the results of a simplified modelling assuming an increased stress-free temperature in the range of the operation temperature shows also a good agreement, esp. using the materials characteristics of KTA. [German] Die Innenoberflaeche von Reaktordruckbehaeltern aus ferritischen Werkstoffen wird zum Schutz gegen Korrosion mit einer austenitischen Plattierung versehen. Diese wird ueblicherweise als zweilagige Schweissplattierung ausgefuehrt, um die Bildung von Unterplattierungsfehlern zu vermeiden und die mikrostrukturellen Eigenschaften des Plattierungswerkstoffs zu verbessern. Auf der

  2. The Effect of Some 4,2 and 5,2 Bisthiazole Derivatives on Nitro-Oxidative Stress and Phagocytosis in Acute Experimental Inflammation

    Directory of Open Access Journals (Sweden)

    Cătălin Araniciu

    2014-07-01

    Full Text Available Nineteen bisthiazoles were tested in order to assess their anti-inflammatory and antioxidant properties. First, we evaluated the in vitro direct antioxidant capacity of the bisthiazoles using the DPPH radical scavenging method. Then, the anti-inflammatory effect was tested in acute rat experimental inflammation by measuring the acute phase bone marrow response, the phagocytic capacity and the serum nitro-oxidative stress status. Although none of the substances showed significant direct antioxidant potential in the DPPH assay, most of them improved serum oxidative status, when administered to rats with inflammation. Four of the bisthiazoles proved to have good anti-inflammatory properties, similar or superior to that of equal doses meloxicam.

  3. Do changes in affect moderate the association between attachment anxiety and body dissatisfaction in children? An experimental study by means of the Trier Social Stress Test.

    Science.gov (United States)

    Goossens, Lien; Van Durme, Kim; Van Beveren, Marie-Lotte; Claes, Laurence

    2017-08-01

    Previous studies have already found a positive association between attachment and disordered eating attitudes and behaviors in children and adolescents. However, to our knowledge, no experimental studies have examined whether changes in negative and/or positive affect moderate the association between attachment anxiety and body dissatisfaction in children. A controlled laboratory setting was used to investigate whether changes in state negative and/or positive affect moderate the association between attachment anxiety and body satisfaction in a sample of 81 children (Mage=11.74). The changes in state affect were caused by the exposure to a performance-related stressor using the Trier Social Stress Test for Children. Children with high levels of attachment anxiety reported a decrease in body satisfaction, but only if the TSST-C led to a decrease in their positive affect. Early detection and intervention programs may benefit from addressing insecure attachment and maladaptive emotion regulation in children. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Parental Care in a Stressful World: Experimentally Elevated Cortisol and Brood Size Manipulation Influence Nest Success Probability and Nest-Tending Behavior in a Wild Teleost Fish.

    Science.gov (United States)

    Algera, Dirk A; Gutowsky, Lee F G; Zolderdo, Aaron J; Cooke, Steven J

    Parental care is an advantageous reproductive behavior, as the fitness of the caregiver is increased through improving the chances of its offspring's survival. Parental care occurs in a variety of teleost fishes. The body size of parental fish and the size of their brood can affect nest abandonment decisions, where compared with smaller fish with smaller broods, larger fish with larger broods typically invest more energy into reproductive events because they have less future reproductive potential. Although essential for basal metabolism and body maintenance functions, when glucocorticoid hormones (e.g., cortisol) are chronically elevated, as can occur during stress, fish may experience impairments in behavior and immune function, leading to compromised health and condition. Anthropogenic stressors during parental care can lead to elevated stress, therefore making it necessary to understand how stress influences an already-challenging period. Using smallmouth bass as a model, a gradient of body sizes, and experimentally manipulated brood size (i.e., reducing large broods and supplementing small broods) and cortisol levels (i.e., elevated via slow-release intraperitoneal cocoa butter implants containing cortisol versus controls), we tested the hypothesis that the reproductive success and parental care behaviors (i.e., aggression, nest tending) of nest-guarding male smallmouth bass are influenced by parental body size, brood size, and cortisol level. Overall, there was a relationship between cortisol treatment and nest success in which larger fish exhibited lower success when cortisol levels were elevated. Brood size had a significant effect on fish-tending behavior, independent of cortisol level and body size. Lending partial support to our hypothesis, the results of this study indicate that the reproductive success of guarding male smallmouth bass is influenced by cortisol level and that tending behavior is affected by brood size.

  5. Modulatory effects of cod liver oil on the antioxidant status and oxidative stress induced by acute exposure to carbon tetrachloride (CCL4) in experimental animal models.

    Science.gov (United States)

    Omugba, Abam Esther; Ajiboye, Adebayo J; Oyagbemi, Ademola A; Agofure, Eze

    2015-05-01

    This work was designed to investigate the modulatory effects of cod liver oil on the acute exposure to carbon tetrachloride (CCL4) in experimental animal models. Markers of oxidative stress, enzymic and non-enzymic antioxidants were assessed in the liver and kidney. The results showed significant (poil compared to the control and CCL4-treated groups. Acute exposure to CCL4 also significantly (preactive substances in the liver of rats treated with cod liver oil compared to the CCL4-treated rats. The reduced glutathione (GSH) content in the liver of the rats administered with CCL4 decreased significantly compared to that in all other treatment groups, whereas rats pretreated and co-administered with cod liver oil and CCl4 showed significant (poil compared to the CCl4 only-treated group. The percentage inhibition of superoxide dismutase (SOD) increased (poil compared to the CCL4-treated rats and the control. Taken together, cod liver oil attenuates CCL4-induced toxicity and oxidative stress in the liver but not in the kidney of rats acutely exposed to CCL4.

  6. How closely does stem growth of adult beech (Fagus sylvatica) relate to net carbon gain under experimentally enhanced ozone stress?

    Science.gov (United States)

    Kitao, Mitsutoshi; Winkler, J Barbro; Löw, Markus; Nunn, Angela J; Kuptz, Daniel; Häberle, Karl-Heinz; Reiter, Ilja M; Matyssek, Rainer

    2012-07-01

    The hypothesis was tested that O(3)-induced changes in leaf-level photosynthetic parameters have the capacity of limiting the seasonal photosynthetic carbon gain of adult beech trees. To this end, canopy-level photosynthetic carbon gain and respiratory carbon loss were assessed in European beech (Fagus sylvatica) by using a physiologically based model, integrating environmental and photosynthetic parameters. The latter were derived from leaves at various canopy positions under the ambient O(3) regime, as prevailing at the forest site (control), or under an experimental twice-ambient O(3) regime (elevated O(3)), as released through a free-air canopy O(3) fumigation system. Gross carbon gain at the canopy-level declined by 1.7%, while respiratory carbon loss increased by 4.6% under elevated O(3). As this outcome only partly accounts for the decline in stem growth, O(3)-induced changes in allocation are referred to and discussed as crucial in quantitatively linking carbon gain with stem growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Experimental Research on Therapeutic Efficacy of Traditional Chinese Medicine Shengjing Capsule Extracts in Treating Spermatogenesis Impairment Induced by Oxidative Stress.

    Science.gov (United States)

    Zhou, Shaohu; Wen, Zhiwei; Liang, Aijun; Zhang, Shuting

    2016-01-05

    To investigate antioxidant effects of traditional Chinese Shengjing capsule extracts (sperm-producing capsule, with functions of tonifying kidney and invigorating kidney essence) on testes, epididymides, and sperms of rats. We randomly divided 50 rats into 5 groups. G1: normal control group (treated with saline); G2: cadmium chloride group; G3: cadmium chloride+ low doses of drugs; G4: cadmium chloride + medium doses of drugs; and G5: cadmium chloride + high doses of drugs (equivalent dose: 0.45 g/kg). In addition to the normal control group, the other 4 groups started receiving intraperitoneal injection of cadmium chloride (1 mg/kg, i.p.). Testicular glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), and malondialdehyde aldehyde (MDA) were measured by ELISA; epididymis histopathological examination was performed; testis serum testosterone (T) was measured; specimens of the epididymal semen were analyzed for sperm concentration, morphology, vitality, and DNA fragmentation rate. Sperm count and activity of rats in the model control group decreased significantly; their MDA concentration of testicular and epididymal homogenates increased greatly; while the vitality of SOD and GSH-Px dropped sharply. All indexes mentioned above were significantly different from those of the blank control group (P<0.05); the sperm count and activity of rats treated with Shengjing capsule (sperm-producing capsule) decreased, but were still significantly higher than those of the model group (P<0.05). MDA level of rats treated with Shengjing capsule were significantly lower than that of the model group (P<0.05), while their SOD and GSH-Px activity were significantly higher than the model group (P<0.05). The normal morphology rate and DNA integrity rate of groups treated with Shengjing capsule were significantly higher than those of the model group (P<0.05). Shengjing can enhance the activity of antioxidant enzymes and inhibit oxidative stress. It can also repair testicular and

  8. Experimental – Numerical Analysis of Stress State in Front of the Crack Tip of Modified and Unmodified G17CrMo5-5 Cast Steel by Rare Earth Metals in a Brittle-Ductile Transition Region

    Directory of Open Access Journals (Sweden)

    Dzioba I.

    2016-06-01

    Full Text Available In the paper presented experimental data and numerical analysis of stress distribution in front of the crack of two melts of low-alloy G17CrMo5-5 cast steel-modified (M by rare earth metals and original, unmodified (UM in the temperature range, according to the brittle-ductile transition region. Experimental tests include determination of the tensile properties and fracture toughness characteristics for the UM and M cast steel. Numerical analysis includes determination of stress distribution in front of the crack at the initial moment of the crack extension. In the numerical computations, experimentally tested specimens SEN(B were modeled. The true stress-strain curves for the UM and M cast steel were used in the calculation. It was shown that the maximum of the opening stresses at the initial moment of the crack extension occurs in the axis of the specimens and reaches similar level of about 3.5σ0 for both UM and M cast steel. However, the length of the critical distance, measured for stress level equal 3σ0, is great for the M in comparison to the UM cast steel. Also was shown that the UM cast steel increased the level of the stress state triaxiality parameters that resulted in a decrease of fracture toughness.

  9. Everyday stress response targets in the science of behavior change.

    Science.gov (United States)

    Smyth, Joshua M; Sliwinski, Martin J; Zawadzki, Matthew J; Scott, Stacey B; Conroy, David E; Lanza, Stephanie T; Marcusson-Clavertz, David; Kim, Jinhyuk; Stawski, Robert S; Stoney, Catherine M; Buxton, Orfeu M; Sciamanna, Christopher N; Green, Paige M; Almeida, David M

    2017-09-28

    Stress is an established risk factor for negative health outcomes, and responses to everyday stress can interfere with health behaviors such as exercise and sleep. In accordance with the Science of Behavior Change (SOBC) program, we apply an experimental medicine approach to identifying stress response targets, developing stress response assays, intervening upon these targets, and testing intervention effectiveness. We evaluate an ecologically valid, within-person approach to measuring the deleterious effects of everyday stress on physical activity and sleep patterns, examining multiple stress response components (i.e., stress reactivity, stress recovery, and stress pile-up) as indexed by two key response indicators (negative affect and perseverative cognition). Our everyday stress response assay thus measures multiple malleable stress response targets that putatively shape daily health behaviors (physical activity and sleep). We hypothesize that larger reactivity, incomplete recovery, and more frequent stress responses (pile-up) will negatively impact health behavior enactment in daily life. We will identify stress-related reactivity, recovery, and response in the indicators using coordinated analyses across multiple naturalistic studies. These results are the basis for developing a new stress assay and replicating the initial findings in a new sample. This approach will advance our understanding of how specific aspects of everyday stress responses influence health behaviors, and can be used to develop and test an innovative ambulatory intervention for stress reduction in daily life to enhance health behaviors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Assessment of the Contour Method for 2-D Cross Sectional Residual Stress Measurements of Friction Stir Welded Parts of AA2024-T3—Numerical and Experimental Comparison

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Carlone, Pierpaolo; Hattel, Jesper Henri

    2017-01-01

    The contour method is one of the newest techniques for obtaining residual stress fields from friction stir welded (FSW) parts, experimentally. This method has many advantages; however, edge effects coming from the process itself might introduce artifacts in the obtained results, and this was slig......The contour method is one of the newest techniques for obtaining residual stress fields from friction stir welded (FSW) parts, experimentally. This method has many advantages; however, edge effects coming from the process itself might introduce artifacts in the obtained results......, and consequently this should not be interpreted as a misleading result of the contour method. Edge effects from the cutting process involved in the contour method should, however, be taken into consideration, most likely resulting in the residual stresses observed near the surfaces of the cross section being less...

  11. Inflammation and oxidative stress in corneal tissue in experimental keratitis due to Fusarium solani: Amelioration following topical therapy with voriconazole and epigallocatechin gallate.

    Science.gov (United States)

    Ruban, Vasanthakumar V; Archana, Philip T; Sundararajan, Mahalingam; Geraldine, Pitchairaj; Thomas, Philip A

    2017-10-24

    Combined antifungal and antioxidant therapy may help to reduce oxidative stress in fungal keratitis. Experimental Fusarium solani keratitis was induced by application of F. solani conidia to scarified cornea (right eye) of 16 rabbits (another four rabbits were negative controls [Group I]). Five days later, F. solani-infected animals began receiving hourly topical saline alone (Group II), voriconazole (10 mg/mL) alone (Group III), epigallocatechin gallate (EGCG, 10 mg/mL) alone (Group IV) or voriconazole and EGCG (Group V). Twenty days post-inoculation, corneal lesions were graded. After animal sacrifice, excised corneas underwent histopathological and microbiological investigations. Corneal tissue levels/activities of interleukin 1 beta (IL-1β) and tumour necrosis factor alpha (TNF-α) gene mRNA transcripts, matrix metalloproteinase (MMP) 2 and 9 proteins, malondialdehyde (MDA) and reduced glutathione (GSH), and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), were also measured. Clinical and histopathological scores (severity of corneal lesions; [P  Groups IV and III > Groups V and I. Mean SOD, CAT, GPx and GSH levels (P solani keratitis, as manifested by improved clinical, histological, microbiological and molecular parameters. © 2017 Blackwell Verlag GmbH.

  12. Construction and Experimental Validation of a Quantitative Kinetic Model of Nitric Oxide Stress in Enterohemorrhagic Escherichia coli O157:H7

    Directory of Open Access Journals (Sweden)

    Jonathan L. Robinson

    2016-02-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC are responsible for large outbreaks of hemorrhagic colitis, which can progress to life-threatening hemolytic uremic syndrome (HUS due to the release of Shiga-like toxins (Stx. The presence of a functional nitric oxide (NO· reductase (NorV, which protects EHEC from NO· produced by immune cells, was previously found to correlate with high HUS incidence, and it was shown that NorV activity enabled prolonged EHEC survival and increased Stx production within macrophages. To enable quantitative study of EHEC NO· defenses and facilitate the development of NO·-potentiating therapeutics, we translated an existing kinetic model of the E. coli K-12 NO· response to an EHEC O157:H7 strain. To do this, we trained uncertain model parameters on measurements of [NO·] and [O2] in EHEC cultures, assessed parametric and prediction uncertainty with the use of a Markov chain Monte Carlo approach, and confirmed the predictive accuracy of the model with experimental data from genetic mutants lacking NorV or Hmp (NO· dioxygenase. Collectively, these results establish a methodology for the translation of quantitative models of NO· stress in model organisms to pathogenic sub-species, which is a critical step toward the application of these models for the study of infectious disease.

  13. The influence of stress on the relationship between cognitive variables and measures of eating disorders (in healthy female university students): a quasi-experimental study.

    Science.gov (United States)

    Ruggiero, G M; Bertelli, S; Boccalari, L; Centorame, F; Ditucci, A; La Mela, C; Scarinci, A; Vinai, P; Scarone, S; Sassaroli, S

    2008-09-01

    Perfectionism, poor self-esteem and stress have all been described as important risk factors for eating disorders. The purpose of this study was to assess whether a stressful situation is significantly correlated to and associated with significantly higher levels of perfectionism, stress, quantifiable measures of eating disorders, and with significantly lower levels of self-esteem in a non-clinical sample. Thirty-five female university students completed the Multidimensional Perfectionism Scale, the Rosenberg Self-Esteem Scale, the Perceived Stress Scale, and the Eating Disorder Inventory two times; once on an average university day and once on the day of an exam. Descriptive statistics and t-tests were calculated to verify whether a stressful situation was associated with a significant difference in levels of perfectionism, self-esteem, stress, and measures of eating disorders. Bivariate correlations were calculated for both the stress and non-stress situation, to observe how the dimensions of perfectionism, self-esteem, and stress were associated with measures of eating disorders. During the stress situation, the study participants had, on average, significantly higher levels of concern over mistakes, body dissatisfaction, drive for thinness, and perceived stress. Bivariate correlations revealed that during the stress situation perceived stress, cognitive variables and measures of eating disorders showed significant correlations with each other that were absent in the non stress situation. The results of the present study suggest that the dimensions of pathological perfectionism, low self-esteem, and perceived stress are related to an increase in dieting thoughts and dissatisfaction with body aspect in non-clinical women during a performance that could potentially challenge the perception of their self-esteem. The stressful situation can be interpreted as an experience of invalidation, which could explain the connection between cognitive constructs and behaviours

  14. Analysing the effect of stand density and site conditions on structure and growth of oak species using Nelder trials along an environmental gradient: experimental design, evaluation methods, and results

    Directory of Open Access Journals (Sweden)

    Enno Uhl

    2015-05-01

    Full Text Available Background Most current approaches in forest science and practice require information about structure and growth of individual trees rather than - or in addition to - sum and mean values of growth and yield at forest stand level as provided by classic experimental designs. By inventing the wheel design, Nelder provided the possibility to turn to the individual tree as basic information unit. Such trials provide valuable insights into the dependency of growth on stand density at particular sites. Methods Here, we present an extension of the original design and evaluation by Nelder. (i We established Nelder wheels along an environmental gradient through Europe in atlantic climate in Belgium and Germany, Mediterranean climate in Italy, continental climate in Hungary as well as on high land climate in Mexico. Such disjunct Nelder wheels along an environmental gradient can be regarded and analysed as a two-factor design with the factors of site condition and stand density. (ii We present an advanced statistical approach to evaluate density dependent growth dynamics of trees planted in form of the Nelder design, which considers spatio-temporal autocorrelation. (iii We prove the usefulness of the methods in improving ecological theory concerning density related productivity, trade-offs between facilitation and competition, and allometric relations between size variables. Results First evaluations based on remeasured Nelder wheels in oak (Quercus roburL. show a size growth differentiation during the first observation period. In particular, height growth is accelerated under higher competition indicating facilitation effects. We detect furthermore a high variability in allometric relations. Conclusions The proposed design, methods, and results are discussed regarding their impact on forest practice, model building, and ecological theory. We conclude that the extended Nelder approach is highly efficient in providing currently lacking individual tree level

  15. An experimental study of the job demand-control model with measures of heart rate variability and salivary alpha-amylase: Evidence of increased stress responses to increased break autonomy.

    Science.gov (United States)

    O'Donnell, Emma; Landolt, Kathleen; Hazi, Agnes; Dragano, Nico; Wright, Bradley J

    2015-01-01

    We assessed in an experimental design whether the stress response towards a work task was moderated by the autonomy to choose a break during the assigned time to complete the task. This setting is defined in accordance with the theoretical framework of the job-demand-control (JDC) model of work related stress. The findings from naturalistic investigations of a stress-buffering effect of autonomy (or 'buffer hypothesis') are equivocal and the experimental evidence is limited, especially with relation to physiological indices of stress. Our objective was to investigate if increased autonomy in a particular domain (break time control) was related with adaptive physiology using objective physiological markers of stress; heart rate variability (HRV) and salivary alpha amylase (sAA). We used a within-subject design and the 60 female participants were randomly assigned to an autonomy (free timing of break) and standard conditions (fixed timing of break) of a word processing task in a simulated office environment in a random order. Participants reported increased perceptions of autonomy, no difference in demand and performed worse in the task in the break-time autonomy versus the standard condition. The results revealed support for the manipulation of increased autonomy, but in the opposing direction. Increased autonomy was related with dysregulated physiological reactivity, synonymous with typical increased stress responses. Potentially, our findings may indicate that autonomy is not necessary a resource but could become an additional stressor when it adds additional complexity while the amount of work (demands) remains unchanged. Further, our findings underscore the need to collect objective physiological evidence of stress to supplement self-reported information. Self-report biases may partially explain the inconsistent findings with the buffer hypothesis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Experimental observations on uniaxial whole-life transformation ratchetting and low-cycle stress fatigue of super-elastic NiTi shape memory alloy micro-tubes

    Science.gov (United States)

    Song, Di; Kang, Guozheng; Kan, Qianhua; Yu, Chao; Zhang, Chuanzeng

    2015-07-01

    In this work, the low-cycle fatigue failure of super-elastic NiTi shape memory alloy micro-tubes with a wall thickness of 150 μm is investigated by uniaxial stress-controlled cyclic tests at human body temperature 310 K. The effects of mean stress, peak stress, and stress amplitude on the uniaxial whole-life transformation ratchetting and fatigue failure of the NiTi alloy are observed. It is concluded that the fatigue life depends significantly on the stress levels, and the extent of martensite transformation and its reverse play an important role in determining the fatigue life. High peak stress or complete martensite transformation shortens the fatigue life.

  17. Experiments and Analyses for Determining Fibre/Matrix Interface Parameters – Understanding Debonding Problems

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Gupta, Mohit; Lilholt, Hans

    2013-01-01

    A new experimental technique is developed to monitor the initiation and propagation of adebond crack during a fibre pull-out experiment. The advanced experimental setup consists of a high resolution video camera and a laser extensometer mounted at a tensile test machine. The test setup enables...... the measurement of the fibre/matrix displacement and debond length. A micromechanical model is used for analysing the experimental data. It allows the evaluation of the following parameters: the interface debond energy GIIc and the frictional sliding shear stress τs at the fibre/matrix interface, and the misfit...

  18. An experimental study on effect of antioxidant vitamin E in stress and alcohol induced changes in male fertility in albino rats.

    Directory of Open Access Journals (Sweden)

    Sanghishetti Vijay Prasad, Nayak BB, Ghongane BB, Raul AR, Vijay Kumar AN, Mutalik MM, Kapure NL.

    2012-09-01

    Full Text Available Introduction: Physical and Psychological stresses are believed to reduce sexual functions, resulting fromneurotransmission changes in various erectile response pathways and reduced blood flow in genital organs.Intake of alcohol depends on numerous genetic and environmental factors. Stress has long been thought to influence the alcohol drinking in humans. Forced swimming in laboratory animals has been widely used as a model of stress to study the physiological changes and the capacity of the organism in response to stress. Aim: 1. To assess the effect of forced swimming stress on seminal fluid profile, Serum testosterone level, Testicular lipid peroxidation levels. 2. To assess the effect of Vitamin E on stress induced changes. Method: Adult male albino rats weighing 200 – 220 g, aged 12-15 weeks were used in this study. The animals were randomly divided into four groups of 6 animals each. Group1 (control received distilled water, Group 2 (Forced Swimming Stress received distilled water Group 3: subjected to Forced Swimming stress with 20% alcohol intake p.o. Group 4: Swimming stress with 20% alcohol treated with Vitamin E(200mg/kg/day orally. The following parameters were studied in all groups 1. Body weight. 2. Sperm count Motility and Life /death Ratio (SLDR. 3. Serum Testosterone 4. Testicular Malondialdehyde level (MDA. Results: Forced swimming stress caused loss in body wt, reduction in sperm count, motility and SLDR in sperm analysis, reduction in serum testosterone and increase testicular MDA levels compared to control. All the changes were statistically significant. When alcohol was added along with forced swimming it caused further loss in body wt, sperm count, motility and SLDR, serum testosterone level and slightly further increase in MDA levels. These observations were also statistically significant. In case of group IV in which Vitamin E was administered long with stress with alcohol it showed a trend of reversal phenomenon of

  19. Experimental study of chemical-mechanical coupling during percolation of reactive fluid through rocks under stress, in the context of the CO{sub 2} geological sequestration; Etude experimentale du couplage chimie-mecanique lors de la percolation d'un fluide reactif dans des roches sous contrainte, dans le contexte de la sequestration geologique du CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, Y

    2006-10-15

    CO{sub 2} injection into geological repositories will induce chemical and mechanical instabilities. The study of these instabilities is based on experimental deformation of natural rock samples under stress, in the presence of fluids containing, or not, dissolved CO{sub 2}. Triaxial cells used for the experiments permitted an independent control and measurement of stress, temperature, fluid pressure and composition. Vertical strains were measured during several months, with a resolution of 1.10{sup -12} s{sup -1} on the strain rate. Simultaneously, fluids were analysed in order to quantify fluid-rock interactions. For limestone samples, percolation of CO{sub 2}-rich fluids increases strain rate by a factor 1.7 up to 5; on the other hand, sandstone deformation remained almost the same. Increase in strain rate with limestone samples was explained by injected water acidification by the CO{sub 2} which increases rock solubility and reaction kinetics. On the opposite, small effect of CO{sub 2} on quartz explains the absence of deformation. X-ray observations confirmed the importance of rock composition and structure on the porosity evolution. Numerical simulations of rock elastic properties showed increasing shear stress into the sample. Measured deformation showed an evolution of reservoir rocks mechanical properties. It was interpreted as the consequence of pressure solution mechanisms both at grains contacts and on grain free surfaces. (author)

  20. Experimental and analytical analysis of stress-strain behavior in a (90/0 deg)2s, SiC/Ti-15-3 laminate

    Science.gov (United States)

    Lerch, Bradley A.; Melis, Matthew E.; Tong, Mike

    1991-01-01

    The nonlinear stress strain behavior of 90 degree/0 degree sub 2s, SiC/Ti-15-3 composite laminate was numerically investigated with a finite element, unit cell approach. Tensile stress-strain curves from room temperature experiments depicted three distinct regions of deformation, and these regions were predicted by finite element analysis. The first region of behavior, which was linear elastic, occurred at low applied stresses. As applied stresses increased, fiber/matrix debonding in the 90 degree plies caused a break in the stress-strain curve and initiated a second linear region. In this second region, matrix plasticity in the 90 degree plies developed. The third region, which was typified by nonlinear, stress-strain behavior occr red at high stresses. In this region, the onset of matrix plasticity in the 0 degree plies stiffened the laminate in the direction transverse to the applied load. Metallographic sections confirmed the existence of matrix plasticity in specific areas of the structure. Finite element analysis also predicted these locations of matrix slip.

  1. Predicting the synergy of multiple stress effects

    Science.gov (United States)

    Liess, Matthias; Foit, Kaarina; Knillmann, Saskia; Schäfer, Ralf B.; Liess, Hans-Dieter

    2016-09-01

    Toxicants and other, non-chemical environmental stressors contribute to the global biodiversity crisis. Examples include the loss of bees and the reduction of aquatic biodiversity. Although non-compliance with regulations might be contributing, the widespread existence of these impacts suggests that for example the current approach of pesticide risk assessment fails to protect biodiversity when multiple stressors concurrently affect organisms. To quantify such multiple stress effects, we analysed all applicable aquatic studies and found that the presence of environmental stressors increases individual sensitivity to toxicants (pesticides, trace metals) by a factor of up to 100. To predict this dependence, we developed the “Stress Addition Model” (SAM). With the SAM, we assume that each individual has a general stress capacity towards all types of specific stress that should not be exhausted. Experimental stress levels are transferred into general stress levels of the SAM using the stress-related mortality as a common link. These general stress levels of independent stressors are additive, with the sum determining the total stress exerted on a population. With this approach, we provide a tool that quantitatively predicts the highly synergistic direct effects of independent stressor combinations.

  2. Predicting the synergy of multiple stress effects.

    Science.gov (United States)

    Liess, Matthias; Foit, Kaarina; Knillmann, Saskia; Schäfer, Ralf B; Liess, Hans-Dieter

    2016-09-09

    Toxicants and other, non-chemical environmental stressors contribute to the global biodiversity crisis. Examples include the loss of bees and the reduction of aquatic biodiversity. Although non-compliance with regulations might be contributing, the widespread existence of these impacts suggests that for example the current approach of pesticide risk assessment fails to protect biodiversity when multiple stressors concurrently affect organisms. To quantify such multiple stress effects, we analysed all applicable aquatic studies and found that the presence of environmental stressors increases individual sensitivity to toxicants (pesticides, trace metals) by a factor of up to 100. To predict this dependence, we developed the "Stress Addition Model" (SAM). With the SAM, we assume that each individual has a general stress capacity towards all types of specific stress that should not be exhausted. Experimental stress levels are transferred into general stress levels of the SAM using the stress-related mortality as a common link. These general stress levels of independent stressors are additive, with the sum determining the total stress exerted on a population. With this approach, we provide a tool that quantitatively predicts the highly synergistic direct effects of independent stressor combinations.

  3. Structure-activity relationship of piperine and its synthetic amide analogs for therapeutic potential to prevent experimentally induced ER stress in vitro.

    Science.gov (United States)

    Hammad, Ayat S; Ravindran, Sreenithya; Khalil, Ashraf; Munusamy, Shankar

    2017-05-01

    Endoplasmic reticulum (ER) is the key organelle involved in protein folding and maturation. Emerging studies implicate the role of ER stress in the development of chronic kidney disease. Thus, there is an urgent need for compounds that could ameliorate ER stress and prevent CKD. Piperine and its analogs have been reported to exhibit multiple pharmacological activities; however, their efficacy against ER stress in kidney cells has not been studied yet. Hence, the goal of this study was to synthesize amide-substituted piperine analogs and screen them for pharmacological activity to relieve ER stress using an in vitro model of tunicamycin-induced ER stress using normal rat kidney (NRK-52E) cells. Five amide-substituted piperine analogs were synthesized and their chemical structures were elucidated by pertinent spectroscopic techniques. An in vitro model of ER stress was developed using tunicamycin, and the compounds of interest were screened for their effect on cell viability, and the expression of ER chaperone GRP78, the pro-apoptotic ER stress marker CHOP, and apoptotic caspases 3 and 12 (via western blotting). Our findings indicate that exposure to tunicamycin (0.5 μg/mL) for 2 h induces the expression of GRP78 and CHOP, and apoptotic markers (caspase-3 and caspase-12) and causes a significant reduction in renal cell viability. Pre-treatment of cells with piperine and its cyclohexylamino analog decreased the tunicamycin-induced upregulation of GRP78 and CHOP and cell death. Taken together, our findings demonstrate that piperine and its analogs differentially regulate ER stress, and thus represent potential therapeutic agents to treat ER stress-related renal disorders. Graphical Abstract Piperine (PIP) reduces the expression of ER stress markers (GRP78 and CHOP) induced by pathologic stimuli and consequently decreases the activation of apoptotic caspase-12 and caspase-3; all of which contributes to its chemical chaperone and cytoprotective properties to protect

  4. Salix alba and Populus nigra seedlings resistance to physical hydro-sedimentary stresses: nursery experimental approach compared to in situ measurements

    Science.gov (United States)

    Wintenberger, Coraline; Rodrigues, Stephane; Breheret, Jean-Gabriel; Jugé, Philippe; Villar, Marc

    2014-05-01

    In Europe, riparian Salicaceae is declining following the loss of potential germination areas associated with river management. Nevertheless, as an exception for lowland rivers, the Loire River (France) shows in its middle reaches an efficient sexual regeneration of Populus nigra and Salix alba species on bare sediments deposited during flood events. The study focuses on the influence of flow, sediment dynamics and fluvial maintenance operations on the establishment and survival of black poplar and white willow seedlings during the first year of development in a lowland sandy-gravel river, the Middle Loire. Main questions are: what is the influence of morphological and sedimentary features on seedlings recruitment and how do they withstand the hydro-sedimentary stresses occurring during high flow periods? How fluvial management works, and induced morphology and sedimentary features, modify the sediment dynamics and subsequent establishment and maintenance of seedlings? To answer these questions, we developed an ex-situ approach which allowed, under controlled conditions, to determine the influence of the sedimentological characteristics of the substrate on the development and maintenance of seedlings with a specific focus on the root system. Three experiments were carried out for three sedimentary mixtures from the river (sand, sand-gravel and 0.2 m of sand superimposed on sand-gravel mixture) that correspond to grain size and stratigraphy conditions often observed on bars and secondary channels in the Loire. The experimental design includes 108 plots of 1 m3, with 400 seeds per plot (corresponding to the Loire density measurements) and combining seeds from two species, three sedimentary mixtures, four replicates and three experiments. Experiment 1 (control) is based on the architecture of root systems using the WinRHIZO image analysis software. Experiment 2 is relative to the evaluation of constraints leading to "uprooting" of seedlings. Experiment 3 provides data

  5. Diazepam Potentiates the Antidiabetic, Antistress and Anxiolytic Activities of Metformin in Type-2 Diabetes Mellitus with Cooccurring Stress in Experimental Animals

    Science.gov (United States)

    2014-01-01

    Psychological stress is considered as one of the limiting factors in the management of type-2 diabetes mellitus (T2DM). Therefore, the basic objective of the present study was to evaluate the antidiabetic effect of metformin, diazepam, and their combination in cooccurring T2DM and stress condition (DMS). T2DM was induced in the male rats by administering streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.) with time lag of 15 min. Rats were subjected to two sessions of cold restraint stress paradigm for one hour on the sixth and seventh day after streptozotocin injection. Administration of metformin (25 mg/kg, p.o.) and diazepam (1 mg/kg, p.o.) in combination from the seventh to thirteenth day after streptozotocin injection showed better improvement in glucose tolerance and insulin sensitivity compared to monotherapy of either drug. In addition, the combination significantly attenuated DMS-induced hyperglycemia, hypertriglyceridaemia, hypercorticosteronemia, anxiety-like behavior, and insulin resistance through modulating insulin signaling pathway in the liver compared to monotherapy. Further, improvement of mitochondrial function, integrity, and oxidative stress in hippocampus, hypothalamus, prefrontal cortex, striatum, amygdala, and nucleus accumbens was observed with the combination. Therefore, metformin in combination with diazepam may be a better therapeutic option in the management of T2DM with cooccurring stress condition. PMID:24995322

  6. Diazepam potentiates the antidiabetic, antistress and anxiolytic activities of metformin in type-2 diabetes mellitus with cooccurring stress in experimental animals.

    Science.gov (United States)

    Garabadu, Debapriya; Krishnamurthy, Sairam

    2014-01-01

    Psychological stress is considered as one of the limiting factors in the management of type-2 diabetes mellitus (T2DM). Therefore, the basic objective of the present study was to evaluate the antidiabetic effect of metformin, diazepam, and their combination in cooccurring T2DM and stress condition (DMS). T2DM was induced in the male rats by administering streptozotocin (45 mg/kg, i.p.) and nicotinamide (110 mg/kg, i.p.) with time lag of 15 min. Rats were subjected to two sessions of cold restraint stress paradigm for one hour on the sixth and seventh day after streptozotocin injection. Administration of metformin (25 mg/kg, p.o.) and diazepam (1 mg/kg, p.o.) in combination from the seventh to thirteenth day after streptozotocin injection showed better improvement in glucose tolerance and insulin sensitivity compared to monotherapy of either drug. In addition, the combination significantly attenuated DMS-induced hyperglycemia, hypertriglyceridaemia, hypercorticosteronemia, anxiety-like behavior, and insulin resistance through modulating insulin signaling pathway in the liver compared to monotherapy. Further, improvement of mitochondrial function, integrity, and oxidative stress in hippocampus, hypothalamus, prefrontal cortex, striatum, amygdala, and nucleus accumbens was observed with the combination. Therefore, metformin in combination with diazepam may be a better therapeutic option in the management of T2DM with cooccurring stress condition.

  7. Photoelastic and Finite Element Analyses of Occlusal Loads in Mandibular Body

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Rossi

    2014-01-01

    Full Text Available This study proposed to evaluate the mandibular biomechanics in the posterior dentition based on experimental and computational analyses. The analyses were performed on a model of human mandible, which was modeled by epoxy resin for photoelastic analysis and by computer-aided design for finite element analysis. To standardize the evaluation, specific areas were determined at the lateral surface of mandibular body. The photoelastic analysis was configured through a vertical load on the first upper molar and fixed support at the ramus of mandible. The same configuration was used in the computer simulation. Force magnitudes of 50, 100, 150, and 200 N were applied to evaluate the bone stress. The stress results presented similar distribution in both analyses, with the more intense stress being at retromolar area and oblique line and alveolar process at molar level. This study presented the similarity of results in the experimental and computational analyses and, thus, showed the high importance of morphology biomechanical characterization at posterior dentition.

  8. Stress-induced drinking in parents of boys with attention-deficit-hyperactivity disorder: heterogeneous groups in an experimental study of adult-child interactions.

    Science.gov (United States)

    Kashdan, Todd B; Adams, Leah M; Kleiman, Evan M; Pelham, William E; Lang, Alan R

    2013-08-01

    Research on whether parents of children with externalizing disorders are at elevated risk for alcohol problems is equivocal. To reduce this ambiguity, we examined how individual differences in stress reactivity might moderate the drinking behavior of such parents. Parents (119 mothers, 44 fathers) of ADHD sons interacted with different child confederates during each of two counter-balanced sessions. In one, the confederate portrayed a friendly, cooperative, "normal" boy; in the other, the confederate portrayed a "deviant" boy who exhibited behavior characteristic of externalizing disorders. Following each interaction, parents were given an opportunity for ad lib consumption of alcohol while anticipating a second interaction. Latent class analysis identified three subgroups of parents using distress scores and alcohol consumption: minimal stress reactivity; reacts to child deviance with increased distress, but not increased drinking; marked stress-induced drinking. Decisions about the nature and proper treatment of parents raising children with ADHD may be compromised by failure to attend to individual differences in stress reactivity and inclinations to use drinking to cope.

  9. Effect of variable winds on current structure and Reynolds stresses in a tidal flow: analysis of experimental data in the eastern English Channel

    Directory of Open Access Journals (Sweden)

    K. A. Korotenko

    2012-11-01

    Full Text Available Wind and wave effects on tidal current structure and turbulence throughout the water column are examined using an upward-looking acoustic Doppler current profiler (ADCP. The instrument has been deployed on the seafloor of 18-m mean depth, off the north-eastern French coast in the eastern English Channel, over 12 tidal cycles, and covered the period of the transition from mean spring to neap tide, and forcing regimes varied from calm to moderate storm conditions. During storms, we observed gusty winds with magnitudes reaching 15 m s−1 and wave heights reaching up to 1.3 m. Analysis of velocity spectra revealed a noticeable contribution of wind-induced waves to spectral structure of velocity fluctuations within the subsurface layer. Near the surface, stormy winds and waves produced a significant intensification of velocity fluctuations, particularly when the sustained wind blew against the ebb tide flow. As during wavy periods, the variance-derived Reynolds stress estimates might include a wav