WorldWideScience

Sample records for accompanies late-phase plasticity

  1. Late Protein Synthesis-Dependent Phases in CTA Long-Term Memory: BDNF Requirement

    OpenAIRE

    Martínez-Moreno, Araceli; Rodríguez-Durán, Luis F.; Escobar, Martha L.

    2011-01-01

    It has been proposed that long-term memory persistence requires a late protein synthesis-dependent phase, even many hours after memory acquisition. Brain-derived neurotrophic factor (BDNF) is an essential protein synthesis product that has emerged as one of the most potent molecular mediators for long-term synaptic plasticity. Studies in the rat hippocampus have been shown that BDNF is capable to rescue the late-phase of long-term potentiation as well as the hippocampus-related long-term memo...

  2. Intermittent dislocation density fluctuations in crystal plasticity from a phase-field crystal model

    DEFF Research Database (Denmark)

    Tarp, Jens M.; Angheluta, Luiza; Mathiesen, Joachim

    2014-01-01

    Plastic deformation mediated by collective dislocation dynamics is investigated in the two-dimensional phase-field crystal model of sheared single crystals. We find that intermittent fluctuations in the dislocation population number accompany bursts in the plastic strain-rate fluctuations...... propose a simple stochastic model of dislocation reaction kinetics that is able to capture these statistical properties of the dislocation density fluctuations as a function of shear rate....

  3. PRR11 regulates late-S to G2/M phase progression and induces premature chromatin condensation (PCC)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chundong; Zhang, Ying; Li, Yi; Zhu, Huifang; Wang, Yitao; Cai, Wei [Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing 400016 (China); Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016 (China); Zhu, Jiang [Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016 (China); Ozaki, Toshinori [Laboratory of DNA Damage Signaling, Chiba Cancer Center Research Institute, 666-2 Nitona, Chuohku, Chiba 260-8717 (Japan); Bu, Youquan, E-mail: buyqcn@aliyun.com [Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing 400016 (China); Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing 400016 (China)

    2015-03-13

    Recently, we have demonstrated that proline-rich protein 11 (PRR11) is a novel tumor-related gene product likely implicated in the regulation of cell cycle progression as well as lung cancer development. However, its precise role in cell cycle progression remains unclear. In the present study, we have further investigated the expression pattern and functional implication of PRR11 during cell cycle in detail in human lung carcinoma-derived H1299 cells. According to our immunofluorescence study, PRR11 was expressed largely in cytoplasm, the amount of PRR11 started to increase in the late S phase, and was retained until just before mitotic telophase. Consistent with those observations, siRNA-mediated knockdown of PRR11 caused a significant cell cycle arrest in the late S phase. Intriguingly, the treatment with dNTPs further augmented PRR11 silencing-mediated S phase arrest. Moreover, knockdown of PRR11 also resulted in a remarkable retardation of G2/M progression, and PRR11-knockdown cells subsequently underwent G2 phase cell cycle arrest accompanied by obvious mitotic defects such as multipolar spindles and multiple nuclei. In addition, forced expression of PRR11 promoted the premature Chromatin condensation (PCC), and then proliferation of PRR11-expressing cells was massively attenuated and induced apoptosis. Taken together, our current observations strongly suggest that PRR11, which is strictly regulated during cell cycle progression, plays a pivotal role in the regulation of accurate cell cycle progression through the late S phase to mitosis. - Highlights: • PRR11 started to increase in the late S phase and was retained until just before mitotic telophase. • PRR11-knockdown caused a significant cell cycle arrest in the late S phase and G2 phase. • The treatment with dNTPs further augmented PRR11 silencing-mediated S phase arrest. • PRR11-knockdown led to multipolar spindles and multiple nuclei. • Forced expression of PRR11 promoted the PCC and inhibited

  4. PRR11 regulates late-S to G2/M phase progression and induces premature chromatin condensation (PCC)

    International Nuclear Information System (INIS)

    Zhang, Chundong; Zhang, Ying; Li, Yi; Zhu, Huifang; Wang, Yitao; Cai, Wei; Zhu, Jiang; Ozaki, Toshinori; Bu, Youquan

    2015-01-01

    Recently, we have demonstrated that proline-rich protein 11 (PRR11) is a novel tumor-related gene product likely implicated in the regulation of cell cycle progression as well as lung cancer development. However, its precise role in cell cycle progression remains unclear. In the present study, we have further investigated the expression pattern and functional implication of PRR11 during cell cycle in detail in human lung carcinoma-derived H1299 cells. According to our immunofluorescence study, PRR11 was expressed largely in cytoplasm, the amount of PRR11 started to increase in the late S phase, and was retained until just before mitotic telophase. Consistent with those observations, siRNA-mediated knockdown of PRR11 caused a significant cell cycle arrest in the late S phase. Intriguingly, the treatment with dNTPs further augmented PRR11 silencing-mediated S phase arrest. Moreover, knockdown of PRR11 also resulted in a remarkable retardation of G2/M progression, and PRR11-knockdown cells subsequently underwent G2 phase cell cycle arrest accompanied by obvious mitotic defects such as multipolar spindles and multiple nuclei. In addition, forced expression of PRR11 promoted the premature Chromatin condensation (PCC), and then proliferation of PRR11-expressing cells was massively attenuated and induced apoptosis. Taken together, our current observations strongly suggest that PRR11, which is strictly regulated during cell cycle progression, plays a pivotal role in the regulation of accurate cell cycle progression through the late S phase to mitosis. - Highlights: • PRR11 started to increase in the late S phase and was retained until just before mitotic telophase. • PRR11-knockdown caused a significant cell cycle arrest in the late S phase and G2 phase. • The treatment with dNTPs further augmented PRR11 silencing-mediated S phase arrest. • PRR11-knockdown led to multipolar spindles and multiple nuclei. • Forced expression of PRR11 promoted the PCC and inhibited

  5. Plastic crystal phases of simple water models

    International Nuclear Information System (INIS)

    Aragones, J. L.; Vega, C.

    2009-01-01

    We report the appearance of two plastic crystal phases of water at high pressure and temperature using computer simulations. In one of them the oxygen atoms form a body centered cubic structure (bcc) and in the other they form a face centered cubic structure (fcc). In both cases the water molecules were able to rotate almost freely. We have found that the bcc plastic crystal transformed into a fcc plastic crystal via a Martensitic phase transition when heated at constant pressure. We have performed the characterization and localization in the phase diagram of these plastic crystal phases for the SPC/E, TIP4P, and TIP4P/2005 water potential models. For TIP4P/2005 model free energy calculations were carried out for the bcc plastic crystal and fcc plastic crystal using a new method (which is a slight variation of the Einstein crystal method) proposed for these types of solid. The initial coexistence points for the SPC/E and TIP4P models were obtained using Hamiltonian Gibbs–Duhem integration. For all of these models these two plastic crystal phases appear in the high pressure and temperature region of the phase diagram. It would be of interest to study if such plastic crystal phases do indeed exist for real water. This would shed some light on the question of whether these models can describe satisfactorily the high pressure part of the phase diagram of water, and if not, where and why they fail.

  6. Plasticity and beyond microstructures, crystal-plasticity and phase transitions

    CERN Document Server

    Hackl, Klaus

    2014-01-01

    The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

  7. Pressure-induced irreversible metallization accompanying the phase transitions in S b2S3

    Science.gov (United States)

    Dai, Lidong; Liu, Kaixiang; Li, Heping; Wu, Lei; Hu, Haiying; Zhuang, Yukai; Yang, Linfei; Pu, Chang; Liu, Pengfei

    2018-01-01

    We have revealed S b2S3 to have two phase transitions and to undergo metallization using a diamond anvil cell at around 5.0, 15.0, and 34.0 GPa, respectively. These results were obtained on the basis of high-pressure Raman spectroscopy, temperature-dependent conductivity measurements, atomic force microscopy, high-resolution transmission electron microscopy, and first-principles calculations. The first phase transition at ˜5.0 GPa is an isostructural phase transition, which is manifested in noticeable changes in five Raman-active modes and the slope of the conductivity because of a change in the electronic structure. The second pressure-induced phase transition was characterized by a discontinuous change in the slope of conductivity and a new low-intensity Raman mode at ˜15.0 GPa . Furthermore, a semiconductor-to-metal transition was found at ˜34.0 GPa , which was accompanied by irreversible metallization, and it could be attributed to the permanently plastic deformation of the interlayer spacing. This high-pressure behavior of S b2S3 will help us to understand the universal crystal structure evolution and electrical characteristics for A2B3 -type compounds, and to facilitate their application in electronic devices.

  8. Late Protein Synthesis-Dependent Phases in CTA Long-Term Memory: BDNF Requirement

    Science.gov (United States)

    Martínez-Moreno, Araceli; Rodríguez-Durán, Luis F.; Escobar, Martha L.

    2011-01-01

    It has been proposed that long-term memory (LTM) persistence requires a late protein synthesis-dependent phase, even many hours after memory acquisition. Brain-derived neurotrophic factor (BDNF) is an essential protein synthesis product that has emerged as one of the most potent molecular mediators for long-term synaptic plasticity. Studies in the rat hippocampus have been shown that BDNF is capable to rescue the late-phase of long-term potentiation as well as the hippocampus-related LTM when protein synthesis was inhibited. Our previous studies on the insular cortex (IC), a region of the temporal cortex implicated in the acquisition and storage of conditioned taste aversion (CTA), have demonstrated that intracortical delivery of BDNF reverses the deficit in CTA memory caused by the inhibition of IC protein synthesis due to anisomycin administration during early acquisition. In this work, we first analyze whether CTA memory storage is protein synthesis-dependent in different time windows. We observed that CTA memory become sensible to protein synthesis inhibition 5 and 7 h after acquisition. Then, we explore the effect of BDNF delivery (2 μg/2 μl per side) in the IC during those late protein synthesis-dependent phases. Our results show that BDNF reverses the CTA memory deficit produced by protein synthesis inhibition in both phases. These findings support the notion that recurrent rounds of consolidation-like events take place in the neocortex for maintenance of CTA memory trace and that BDNF is an essential component of these processes. PMID:21960964

  9. Late protein synthesis-dependent phases in CTA long-term memory: BDNF requirement

    Directory of Open Access Journals (Sweden)

    Araceli eMartínez-Moreno

    2011-09-01

    Full Text Available It has been proposed that long-term memory persistence requires a late protein synthesis-dependent phase, even many hours after memory acquisition. Brain-derived neurotrophic factor (BDNF is an essential protein synthesis product that has emerged as one of the most potent molecular mediators for long-term synaptic plasticity. Studies in the rat hippocampus have been shown that BDNF is capable to rescue the late-phase of long-term potentiation as well as the hippocampus-related long-term memory when protein synthesis was inhibited. Our previous studies on the insular cortex (IC, a region of the temporal cortex implicated in the acquisition and storage of conditioned taste aversion (CTA, have demonstrated that intracortical delivery of BDNF reverses the deficit in CTA memory caused by the inhibition of IC protein synthesis due to anisomycin administration during early acquisition. In this work, we first analyze whether CTA memory storage is protein synthesis dependent in different time-windows. We observed that CTA memory become sensible to protein synthesis inhibition 5 and 7 hours after acquisition. Then, we explore the effect of BDNF delivery (2 μg/2 μl per side in the IC during those late protein synthesis-dependent phases. Our results show that BDNF reverses the CTA memory deficit produced by protein synthesis inhibition in both phases. These findings support the notion that recurrent rounds of consolidation-like events take place in the neocortex for maintenance of CTA memory trace and that BDNF is an essential component of these processes.

  10. Late Protein Synthesis-Dependent Phases in CTA Long-Term Memory: BDNF Requirement.

    Science.gov (United States)

    Martínez-Moreno, Araceli; Rodríguez-Durán, Luis F; Escobar, Martha L

    2011-01-01

    It has been proposed that long-term memory (LTM) persistence requires a late protein synthesis-dependent phase, even many hours after memory acquisition. Brain-derived neurotrophic factor (BDNF) is an essential protein synthesis product that has emerged as one of the most potent molecular mediators for long-term synaptic plasticity. Studies in the rat hippocampus have been shown that BDNF is capable to rescue the late-phase of long-term potentiation as well as the hippocampus-related LTM when protein synthesis was inhibited. Our previous studies on the insular cortex (IC), a region of the temporal cortex implicated in the acquisition and storage of conditioned taste aversion (CTA), have demonstrated that intracortical delivery of BDNF reverses the deficit in CTA memory caused by the inhibition of IC protein synthesis due to anisomycin administration during early acquisition. In this work, we first analyze whether CTA memory storage is protein synthesis-dependent in different time windows. We observed that CTA memory become sensible to protein synthesis inhibition 5 and 7 h after acquisition. Then, we explore the effect of BDNF delivery (2 μg/2 μl per side) in the IC during those late protein synthesis-dependent phases. Our results show that BDNF reverses the CTA memory deficit produced by protein synthesis inhibition in both phases. These findings support the notion that recurrent rounds of consolidation-like events take place in the neocortex for maintenance of CTA memory trace and that BDNF is an essential component of these processes.

  11. Response in the late phase to a radiological emergency

    International Nuclear Information System (INIS)

    Morrey, M.; Nisbet, A.; Thome, D.; Savkin, M.; Hoe, S.; Brynildsen, L.

    2004-01-01

    This paper looks at the key issues that need to be addressed during the transition from the emergency phase to the late phase of a radioactive release, and the development of the initial late phase strategy. It discusses the extent to which current national plans and international advice address the needs of decision makers following contamination of inhabited areas and food production systems. Based on this the following recommendations are made: (1) the issues that will arise at the start of the late phase response to a radioactive release require preparation work in advance of any release; (2) this preparation should consider the adequacy of legislation, technical data and modelling, options for waste storage and disposal, resources for monitoring and implementing clean up; (3) late phase preparedness requires regular exercising and (4) the possibility of terrorist releases adds further emphasis to the need for preparedness for the late phase. (authors)

  12. Late-time cosmological phase transitions

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1990-11-01

    It is shown that the potential galaxy formation and large-scale structure problems of objects existing at high redshifts (Z approx-gt 5), structures existing on scales of 100M pc as well as velocity flows on such scales, and minimal microwave anisotropies (ΔT/T) approx-lt 10 -5 can be solved if the seeds needed to generate structure form in a vacuum phase transition after decoupling. It is argued that the basic physics of such a phase transition is no more exotic than that utilized in the more traditional GUT scale phase transitions, and that, just as in the GUT case, significant random gaussian fluctuations and/or topological defects can form. Scale lengths of ∼100M pc for large-scale structure as well as ∼1 M pc for galaxy formation occur naturally. Possible support for new physics that might be associated with such a late-time transition comes from the preliminary results of the SAGE solar neutrino experiment, implying neutrino flavor mixing with values similar to those required for a late-time transition. It is also noted that a see-saw model for the neutrino masses might also imply a tau neutrino mass that is an ideal hot dark matter candidate. However, in general either hot or cold dark matter can be consistent with a late-time transition. 47 refs., 2 figs

  13. Hippocampal structural plasticity accompanies the resulting contextual fear memory following stress and fear conditioning.

    Science.gov (United States)

    Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

    2013-10-15

    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to stress prevented both the enhancement of fear retention and an increase in the density of total and mature dendritic spines in DH. These findings emphasize the role of the stress-induced attenuation of GABAergic neurotransmission in BLA in the promoting influence of stress on fear memory and on synaptic remodeling in DH. In conclusion, the structural remodeling in DH accompanied the facilitated fear memory following a combination of fear conditioning and stressful stimulation.

  14. Structural conditions of maximal plasticity of two-phase metal materials

    International Nuclear Information System (INIS)

    Movchan, B.A.

    1975-01-01

    Analysis is given of experimental values of the strength and plasticity of iron- and tungsten-based two-phase materials with the regulated amount of the second phase and the grain size. Specimens in the form of a 120 mm x 200 mm sheet with a thickness of 0.8-1.2 mm are prepared by means of the electron beam evaporation technique and subsequent condensation of the materials on a preheated support. The variable content of the second phase along the sheet in the range 0.5 volume per cent and more than a 10-fold change in the grain size of the metallic matrix are attained by a simultaneous evaporation of pure metal (99.98 per cent) and nonlmetallic material-niobium carbide or zirconium dioxide ZrO 2 -from two separate sources. The content of arbitrarily distributed spherical particles of the second phase corresponding to a maximum of the plasticity depends only on the structural parameter - the d/D ratio. The absolute falue of the plasticity and its dependence on the temperature is a complex function of many variables - mechanical properties of particles and the matrix, peculiarities of interphase interaction on the boundary particle - matrix, the size of particles, the rate of plastic deformation and relaxation processes

  15. In-situ characterization of transformation plasticity during an isothermal austenite-to-bainite phase transformation

    International Nuclear Information System (INIS)

    Holzweissig, M.J.; Canadinc, D.; Maier, H.J.

    2012-01-01

    This paper elucidates the stress-induced variant selection process during the isothermal austenite-to-bainite phase transformation in a tool steel. Specifically, a thorough set of experiments combining electron backscatter diffraction and in-situ digital image correlation (DIC) was carried out to establish the role of superimposed stress level on the evolution of transformation plasticity (TP) strains. The important finding is that TP increases concomitant with the superimposed stress level, and strain localization accompanies phase transformation at all stress levels considered. Furthermore, TP strain distribution within the whole material becomes more homogeneous with increasing stress, such that fewer bainitic variants are selected to grow under higher stresses, yielding a more homogeneous strain distribution. In particular, the bainitic variants oriented along [101] and [201] directions are favored to grow parallel to the loading axis and are associated with large TP strains. Overall, this very first in-situ DIC investigation of the austenite-to-bainite phase transformation in steels evidences the clear relationship between the superimposed stress level, variant selection, and evolution of TP strains. - Highlights: ► Local variations of strain were observed by DIC throughout the phase transformation. ► The study clearly established the role of the stress-induced variant selection. ► Variant selection is a key parameter that governs distortion.

  16. Late time phase transition as dark energy

    Indian Academy of Sciences (India)

    Abstract. We show that the dark energy field can naturally be described by the scalar condensates of a non-abelian gauge group. This gauge group is unified with the standard model gauge groups and it has a late time phase transition. The small phase transition explains why the positive acceleration of the universe is ...

  17. Plasticity analysis of nano-grain-sized NiAl alloy in an atomic scale

    International Nuclear Information System (INIS)

    Wang Jingyang; Wang Xiaowei; Rifkin, J.; Li Douxing

    2001-12-01

    The molecular dynamics method is used to simulate a uniaxial tensile deformation of 3.8nm nano-NiAl alloy with curved amorphous-like interfaces at 0K. Plastic deformation behaviour is studied by examining the strain-stress relationship and the microstructural evolution characteristic. Atomic level analysis showed that the micro-strain is essentially heterogeneous in simulated nano-phase samples. The plastic deformation is not only attributed to the plasticity of interfaces, but also accompanied with the plastic shear strain mechanism inside lattice distortion regions and grains. (author)

  18. In-situ characterization of transformation plasticity during an isothermal austenite-to-bainite phase transformation

    Energy Technology Data Exchange (ETDEWEB)

    Holzweissig, M.J., E-mail: martinh@mail.upb.de [University of Paderborn, Lehrstuhl fuer Werkstoffkunde (Materials Science), 33095 Paderborn (Germany); Canadinc, D., E-mail: dcanadinc@ku.edu.tr [Koc University, Advanced Materials Group, Department of Mechanical Engineering, 34450 Istanbul (Turkey); Maier, H.J., E-mail: hmaier@mail.upb.de [University of Paderborn, Lehrstuhl fuer Werkstoffkunde (Materials Science), 33095 Paderborn (Germany)

    2012-03-15

    This paper elucidates the stress-induced variant selection process during the isothermal austenite-to-bainite phase transformation in a tool steel. Specifically, a thorough set of experiments combining electron backscatter diffraction and in-situ digital image correlation (DIC) was carried out to establish the role of superimposed stress level on the evolution of transformation plasticity (TP) strains. The important finding is that TP increases concomitant with the superimposed stress level, and strain localization accompanies phase transformation at all stress levels considered. Furthermore, TP strain distribution within the whole material becomes more homogeneous with increasing stress, such that fewer bainitic variants are selected to grow under higher stresses, yielding a more homogeneous strain distribution. In particular, the bainitic variants oriented along [101] and [201] directions are favored to grow parallel to the loading axis and are associated with large TP strains. Overall, this very first in-situ DIC investigation of the austenite-to-bainite phase transformation in steels evidences the clear relationship between the superimposed stress level, variant selection, and evolution of TP strains. - Highlights: Black-Right-Pointing-Pointer Local variations of strain were observed by DIC throughout the phase transformation. Black-Right-Pointing-Pointer The study clearly established the role of the stress-induced variant selection. Black-Right-Pointing-Pointer Variant selection is a key parameter that governs distortion.

  19. On the Importance of the Flare's Late Phase for the Solar Extreme Ultraviolet Irradiance

    Science.gov (United States)

    Woods, Thomas N.; Eparvier, Frank; Jones, Andrew R.; Hock, Rachel; Chamberlin, Phillip C.; Klimchuk, James A.; Didkovsky, Leonid; Judge, Darrell; Mariska, John; Bailey, Scott; hide

    2011-01-01

    The new solar extreme ultraviolet (EUV) irradiance observations from NASA Solar Dynamics Observatory (SDO) have revealed a new class of solar flares that are referred to as late phase flares. These flares are characterized by the hot 2-5 MK coronal emissions (e.g., Fe XVI 33.5 nm) showing large secondary peaks that appear many minutes to hours after an eruptive flare event. In contrast, the cool 0.7-1.5 MK coronal emissions (e.g., Fe IX 17.1 nm) usually dim immediately after the flare onset and do not recover until after the delayed second peak of the hot coronal emissions. We refer to this period of 1-5 hours after the fl amrea sin phase as the late phase, and this late phase is uniquely different than long duration flares associated with 2-ribbon flares or large filament eruptions. Our analysis of the late phase flare events indicates that the late phase involves hot coronal loops near the flaring region, not directly related to the original flaring loop system but rather with the higher post-eruption fields. Another finding is that space weather applications concerning Earth s ionosphere and thermosphere need to consider these late phase flares because they can enhance the total EUV irradiance flare variation by a factor of 2 when the late phase contribution is included.

  20. Diurnal phase of late-night against late-afternoon of stratiform and convective precipitation in summer southern contiguous China

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rucong [Chinese Academy of Sciences, LASG, Institute of Atmospheric Physics, Beijing (China); China Meteorological Administration, LaSW, Chinese Academy of Meteorological Sciences, Beijing (China); Yuan, Weihua [Chinese Academy of Sciences, LASG, Institute of Atmospheric Physics, Beijing (China); Graduate School of the Chinese Academy of Sciences, Beijing (China); Li, Jian [China Meteorological Administration, LaSW, Chinese Academy of Meteorological Sciences, Beijing (China); Fu, Yunfei [Chinese Academy of Sciences, LASG, Institute of Atmospheric Physics, Beijing (China); University of Science and Technology of China, Laboratory of Satellite Remote Sensing and Climate Environment, Hefei, Anhui (China)

    2010-09-15

    Using the tropical rainfall measuring mission (TRMM) Precipitation Radar (PR) observations combined with the surface rain gauge data during 1998-2006, the robust diurnal features of summer stratiform and convective precipitation over the southern contiguous China are revealed by exploring the diurnal variations of rain rate and precipitation profile. The precipitation over the southern contiguous China exhibits two distinguishing diurnal phases: late-night (2200-0600 LST) and late-afternoon (1400-2200 LST), dependent on the location, precipitation type and duration time. Generally, the maximum rain rate and the highest profile of stratiform precipitation occur in the late-afternoon (late-night) over the southeastern (southwestern) China, while most of the stratiform short-duration rain rate tends to present late-afternoon peaks over the southern China. For convective precipitation, the maximum rain rate and the highest profile occur in the late-afternoon over most of the southern contiguous China, while the convective long-duration rain rate exhibits late-night peaks over the southwestern China. Without regional dependence, the convective precipitation exhibits much larger amplitude of diurnal variations in both near surface rain rate and vertical extension compared with stratiform precipitation and the convective rain top rises most rapidly between noon and afternoon. However, there are two distinctive sub-regions. The diurnal phases of precipitation there are very weakly dependent on precipitation type and duration time. Over the eastern periphery of the Tibetan Plateau, the maximum rain rate and the highest profile of either convective or stratiform precipitation occur in the late-night. Over the southeastern coastal regions, both the near surface rain rate and rain top of convective and stratiform precipitation peak in the late-afternoon. (orig.)

  1. Models and correlations of the DEBRIS Late-Phase Melt Progression Model

    International Nuclear Information System (INIS)

    Schmidt, R.C.; Gasser, R.D.

    1997-09-01

    The DEBRIS Late Phase Melt Progression Model is an assembly of models, embodied in a computer code, which is designed to treat late-phase melt progression in dry rubble (or debris) regions that can form as a consequence of a severe core uncover accident in a commercial light water nuclear reactor. The approach is fully two-dimensional, and incorporates a porous medium modeling framework together with conservation and constitutive relationships to simulate the time-dependent evolution of such regions as various physical processes act upon the materials. The objective of the code is to accurately model these processes so that the late-phase melt progression that would occur in different hypothetical severe nuclear reactor accidents can be better understood and characterized. In this report the models and correlations incorporated and used within the current version of DEBRIS are described. These include the global conservation equations solved, heat transfer and fission heating models, melting and refreezing models (including material interactions), liquid and solid relocation models, gas flow and pressure field models, and the temperature and compositionally dependent material properties employed. The specific models described here have been used in the experiment design analysis of the Phebus FPT-4 debris-bed fission-product release experiment. An earlier DEBRIS code version was used to analyze the MP-1 and MP-2 late-phase melt progression experiments conducted at Sandia National Laboratories for the US Nuclear Regulatory Commission

  2. A Sensitive Period for Language in the Visual Cortex: Distinct Patterns of Plasticity in Congenitally versus Late Blind Adults

    Science.gov (United States)

    Bedny, Marina; Pascual-Leone, Alvaro; Dravida, Swethasri; Saxe, Rebecca

    2012-01-01

    Recent evidence suggests that blindness enables visual circuits to contribute to language processing. We examined whether this dramatic functional plasticity has a sensitive period. BOLD fMRI signal was measured in congenitally blind, late blind (blindness onset 9-years-old or later) and sighted participants while they performed a sentence…

  3. Plasticizers used in food-contact materials affect adipogenesis in 3T3-L1 cells.

    Science.gov (United States)

    Pomatto, Valentina; Cottone, Erika; Cocci, Paolo; Mozzicafreddo, Matteo; Mosconi, Gilberto; Nelson, Erik Russel; Palermo, Francesco Alessandro; Bovolin, Patrizia

    2018-04-01

    Recent studies suggest that exposure to some plasticizers, such as Bisphenol A (BPA), play a role in endocrine/metabolic dispruption and can affect lipid accumulation in adipocytes. Here, we investigated the adipogenic activity and nuclear receptor interactions of four plasticizers approved for the manufacturing of food-contact materials (FCMs) and currently considered safer alternatives. Differentiating 3T3-L1 mouse preadipocytes were exposed to scalar concentrations (0.01-25 μM) of DiNP (Di-iso-nonyl-phthalate), DiDP (Di-iso-decyl-phthalate), DEGDB (Diethylene glycol dibenzoate), or TMCP (Tri-m-cresyl phosphate). Rosiglitazone, a well-known pro-adipogenic peroxisome proliferator activated receptor gamma (PPARγ) agonist, and the plasticizer BPA were included as reference compounds. All concentrations of plasticizers were able to enhance lipid accumulation, with TMCP being the most effective one. Accordingly, when comparing in silico the ligand binding efficiencies to the nuclear receptors PPARγ and retinoid-X-receptor-alpha (RXRα), TMPC displayed the highest affinity to both receptors. Differently from BPA, the four plasticizers were most effective in enhancing lipid accumulation when added in the mid-late phase of differentiation, thus suggesting the involvement of different intracellular signalling pathways. In line with this, TMCP, DiDP, DiNP and DEGDB were able to activate PPARγ in transient transfection assays, while previous studies demonstrated that BPA acts mainly through other nuclear receptors. qRT-PCR studies showed that all plasticizers were able to increase the expression of CCAAT/enhancer binding protein β (Cebpβ) in the early steps of adipogenesis, and the adipogenesis master gene Pparγ2 in the middle phase, with very similar efficacy to that of Rosiglitazone. In addition, TMCP was able to modulate the expression of both Fatty Acid Binding Protein 4/Adipocyte Protein 2 (Fabp4/Ap2) and Lipoprotein Lipase (Lpl) transcripts in the late phase

  4. Correlation between synaptic plasticity, associated proteins, and rehabilitation training in a rat model of cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Dan Yang; Qian Yu

    2008-01-01

    All motions provide sensory, motoric, and reflexive input to the central nervous system, as well as playing an important role in cerebral functional plasticity and compensation. Cerebral plasticity has become the theoretical basis of neurorehabilitation. Studies of cerebrovascular disease, in particular, demonstrate that regeneration is accompanied by multiple forms of plasticity, such as functional and structural, in different phases of stroke rehabilitation. This study was designed to measure synaptic plasticity and expression of associated proteins to analyze the effect of rehabilitation training on learning and memory in a rat model of cerebral infarction. Results suggest that rehabilitation training increases expression of nerve growth factor associated protein 43, brain-derived neurotrophic factor, and neural cell adhesion molecules, and also promotes cerebral functional plasticity.

  5. Probing the Production of Extreme-ultraviolet Late-phase Solar Flares Using the Model Enthalpy-based Thermal Evolution of Loops

    Science.gov (United States)

    Dai, Yu; Ding, Mingde

    2018-04-01

    Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares that is characterized by a second peak in warm coronal emissions (∼3 MK) several tens of minutes to a few hours after the soft X-ray (SXR) peak. Using the model enthalpy-based thermal evolution of loops (EBTEL), we numerically probe the production of EUV late-phase solar flares. Starting from two main mechanisms of producing the EUV late phase, i.e., long-lasting cooling and secondary heating, we carry out two groups of numerical experiments to study the effects of these two processes on the emission characteristics in late-phase loops. In either of the two processes an EUV late-phase solar flare that conforms to the observational criteria can be numerically synthesized. However, the underlying hydrodynamic and thermodynamic evolutions in late-phase loops are different between the two synthetic flare cases. The late-phase peak due to a long-lasting cooling process always occurs during the radiative cooling phase, while that powered by a secondary heating is more likely to take place in the conductive cooling phase. We then propose a new method for diagnosing the two mechanisms based on the shape of EUV late-phase light curves. Moreover, from the partition of energy input, we discuss why most solar flares are not EUV late flares. Finally, by addressing some other factors that may potentially affect the loop emissions, we also discuss why the EUV late phase is mainly observed in warm coronal emissions.

  6. On a phase field approach for martensitic transformations in a crystal plastic material at a loaded surface

    Science.gov (United States)

    Schmitt, Regina; Kuhn, Charlotte; Müller, Ralf

    2017-07-01

    A continuum phase field model for martensitic transformations is introduced, including crystal plasticity with different slip systems for the different phases. In a 2D setting, the transformation-induced eigenstrain is taken into account for two martensitic orientation variants. With aid of the model, the phase transition and its dependence on the volume change, crystal plastic material behavior, and the inheritance of plastic deformations from austenite to martensite are studied in detail. The numerical setup is motivated by the process of cryogenic turning. The resulting microstructure qualitatively coincides with an experimentally obtained martensite structure. For the numerical calculations, finite elements together with global and local implicit time integration scheme are employed.

  7. Phase-field modelling of ductile fracture: a variational gradient-extended plasticity-damage theory and its micromorphic regularization.

    Science.gov (United States)

    Miehe, C; Teichtmeister, S; Aldakheel, F

    2016-04-28

    This work outlines a novel variational-based theory for the phase-field modelling of ductile fracture in elastic-plastic solids undergoing large strains. The phase-field approach regularizes sharp crack surfaces within a pure continuum setting by a specific gradient damage modelling. It is linked to a formulation of gradient plasticity at finite strains. The framework includes two independent length scales which regularize both the plastic response as well as the crack discontinuities. This ensures that the damage zones of ductile fracture are inside of plastic zones, and guarantees on the computational side a mesh objectivity in post-critical ranges. © 2016 The Author(s).

  8. Creating physically-based three-dimensional microstructures: Bridging phase-field and crystal plasticity models.

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hojun [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Owen, Steven J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Abdeljawad, Fadi F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hanks, Byron [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    In order to better incorporate microstructures in continuum scale models, we use a novel finite element (FE) meshing technique to generate three-dimensional polycrystalline aggregates from a phase field grain growth model of grain microstructures. The proposed meshing technique creates hexahedral FE meshes that capture smooth interfaces between adjacent grains. Three dimensional realizations of grain microstructures from the phase field model are used in crystal plasticity-finite element (CP-FE) simulations of polycrystalline a -iron. We show that the interface conformal meshes significantly reduce artificial stress localizations in voxelated meshes that exhibit the so-called "wedding cake" interfaces. This framework provides a direct link between two mesoscale models - phase field and crystal plasticity - and for the first time allows mechanics simulations of polycrystalline materials using three-dimensional hexahedral finite element meshes with realistic topological features.

  9. Effects of plasticization and shear stress on phase structure development and properties of soy protein blends.

    Science.gov (United States)

    Chen, Feng; Zhang, Jinwen

    2010-11-01

    In this study, soy protein concentrate (SPC) was used as a plastic component to blend with poly(butylene adipate-co-terephthalate) (PBAT). Effects of SPC plasticization and blend composition on its deformation during mixing were studied in detail. Influence of using water as the major plasticizer and glycerol as the co-plasticizer on the deformation of the SPC phase during mixing was explored. The effect of shear stress, as affected by SPC loading level, on the phase structure of SPC in the blends was also investigated. Quantitative analysis of the aspect ratio of SPC particles was conducted by using ImageJ software, and an empirical model predicting the formation of percolated structure was applied. The experimental results and the model prediction showed a fairly good agreement. The experimental results and statistic analysis suggest that both SPC loading level and its water content prior to compounding had significant influences on development of the SPC phase structure and were correlated in determining the morphological structures of the resulting blends. Consequently, physical and mechanical properties of the blends greatly depended on the phase morphology and PBAT/SPC ratio of the blends.

  10. Nucleolar integrity is required for the maintenance of long-term synaptic plasticity.

    Directory of Open Access Journals (Sweden)

    Kim D Allen

    Full Text Available Long-term memory (LTM formation requires new protein synthesis and new gene expression. Based on our work in Aplysia, we hypothesized that the rRNA genes, stimulation-dependent targets of the enzyme Poly(ADP-ribose polymerase-1 (PARP-1, are primary effectors of the activity-dependent changes in synaptic function that maintain synaptic plasticity and memory. Using electrophysiology, immunohistochemistry, pharmacology and molecular biology techniques, we show here, for the first time, that the maintenance of forskolin-induced late-phase long-term potentiation (L-LTP in mouse hippocampal slices requires nucleolar integrity and the expression of new rRNAs. The activity-dependent upregulation of rRNA, as well as L-LTP expression, are poly(ADP-ribosylation (PAR dependent and accompanied by an increase in nuclear PARP-1 and Poly(ADP ribose molecules (pADPr after forskolin stimulation. The upregulation of PARP-1 and pADPr is regulated by Protein kinase A (PKA and extracellular signal-regulated kinase (ERK--two kinases strongly associated with long-term plasticity and learning and memory. Selective inhibition of RNA Polymerase I (Pol I, responsible for the synthesis of precursor rRNA, results in the segmentation of nucleoli, the exclusion of PARP-1 from functional nucleolar compartments and disrupted L-LTP maintenance. Taken as a whole, these results suggest that new rRNAs (28S, 18S, and 5.8S ribosomal components--hence, new ribosomes and nucleoli integrity--are required for the maintenance of long-term synaptic plasticity. This provides a mechanistic link between stimulation-dependent gene expression and the new protein synthesis known to be required for memory consolidation.

  11. Associative Memory Extinction Is Accompanied by Decayed Plasticity at Motor Cortical Neurons and Persistent Plasticity at Sensory Cortical Neurons.

    Science.gov (United States)

    Guo, Rui; Ge, Rongjing; Zhao, Shidi; Liu, Yulong; Zhao, Xin; Huang, Li; Guan, Sodong; Lu, Wei; Cui, Shan; Wang, Shirlene; Wang, Jin-Hui

    2017-01-01

    Associative memory is essential for cognition, in which associative memory cells and their plasticity presumably play important roles. The mechanism underlying associative memory extinction vs. maintenance remains unclear, which we have studied in a mouse model of cross-modal associative learning. Paired whisker and olfaction stimulations lead to a full establishment of odorant-induced whisker motion in training day 10, which almost disappears if paired stimulations are not given in a week, and then recovers after paired stimulation for an additional day. In mice that show associative memory, extinction and recovery, we have analyzed the dynamical plasticity of glutamatergic neurons in layers II-III of the barrel cortex and layers IV-V of the motor cortex. Compared with control mice, the rate of evoked spikes as well as the amplitude and frequency of excitatory postsynaptic currents increase, whereas the amplitude and frequency of inhibitory postsynaptic currents (IPSC) decrease at training day 10 in associative memory mice. Without paired training for a week, these plastic changes are persistent in the barrel cortex and decayed in the motor cortex. If paired training is given for an additional day to revoke associative memory, neuronal plasticity recovers in the motor cortex. Our study indicates persistent neuronal plasticity in the barrel cortex for cross-modal memory maintenance as well as the dynamical change of neuronal plasticity in the motor cortex for memory retrieval and extinction. In other words, the sensory cortices are essential for long-term memory while the behavior-related cortices with the inability of memory retrieval are correlated to memory extinction.

  12. Associative Memory Extinction Is Accompanied by Decayed Plasticity at Motor Cortical Neurons and Persistent Plasticity at Sensory Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Rui Guo

    2017-06-01

    Full Text Available Associative memory is essential for cognition, in which associative memory cells and their plasticity presumably play important roles. The mechanism underlying associative memory extinction vs. maintenance remains unclear, which we have studied in a mouse model of cross-modal associative learning. Paired whisker and olfaction stimulations lead to a full establishment of odorant-induced whisker motion in training day 10, which almost disappears if paired stimulations are not given in a week, and then recovers after paired stimulation for an additional day. In mice that show associative memory, extinction and recovery, we have analyzed the dynamical plasticity of glutamatergic neurons in layers II–III of the barrel cortex and layers IV–V of the motor cortex. Compared with control mice, the rate of evoked spikes as well as the amplitude and frequency of excitatory postsynaptic currents increase, whereas the amplitude and frequency of inhibitory postsynaptic currents (IPSC decrease at training day 10 in associative memory mice. Without paired training for a week, these plastic changes are persistent in the barrel cortex and decayed in the motor cortex. If paired training is given for an additional day to revoke associative memory, neuronal plasticity recovers in the motor cortex. Our study indicates persistent neuronal plasticity in the barrel cortex for cross-modal memory maintenance as well as the dynamical change of neuronal plasticity in the motor cortex for memory retrieval and extinction. In other words, the sensory cortices are essential for long-term memory while the behavior-related cortices with the inability of memory retrieval are correlated to memory extinction.

  13. Protective actions in the late phase intervention criteria and decision-making

    International Nuclear Information System (INIS)

    Hedemann-Jensen, P.

    2003-01-01

    Full text: In the past 15 years, the Chernobyl and Goiania accidents resulted in extensive postemergency phase response. Large amounts of 137 Cs were released to the environment during these accidents, leading to a prolonged or quasi-prolonged exposure of the affected populations. The experiences gained from these accidents and others have revealed a need for an updated and fully complete system of decision-making an implementation of long-term countermeasures. In the post-release phase it is expected that a reasonably complete picture of radiation and contamination levels and affected areas in the environment is available. In this phase the dominant risks originate from radioactive materials deposited on the ground, mainly from external exposure and ingestion of contaminated foodstuffs. Measured surface contamination density can thus be used to estimate doses from both the external and ingestion exposure pathways and can therefore be used to make decisions about the introduction of countermeasures. The major countermeasures in the late phase of a nuclear or radiological accident where long-lived radionuclides have been dispersed in the environment are relocation/resettlement, foodstuff restrictions, agricultural countermeasures and cleanup of contaminated land. An overview of these late phase countermeasures is given in the paper. In addition, recommendations from the international radiation protection organizations ICRP, IAEA and from the EU on late phase countermeasures are presented together with the background for their derivation. An important aim of late phase countermeasures is to reduce the likely numbers of cancers as much and as effectively as reasonably possible. However, the total health consequences from long-term exposure situations, and of any countermeasures subsequently implemented, include more than the injuries and increased risks directly attributable to radiation exposure. Stressors, such as the perception of the hazard posed by radiation in

  14. Microstructure Evolution and Mechanical Behavior of a Hot-Rolled High-Manganese Dual-Phase Transformation-Induced Plasticity/Twinning-Induced Plasticity Steel

    Science.gov (United States)

    Fu, Liming; Shan, Mokun; Zhang, Daoda; Wang, Huanrong; Wang, Wei; Shan, Aidang

    2017-05-01

    The microstructures and deformation behavior were studied in a high-temperature annealed high-manganese dual-phase (28 vol pct δ-ferrite and 72 vol pct γ-austenite) transformation-induced plasticity/twinning-induced plasticity (TRIP/TWIP) steel. The results showed that the steel exhibits a special Lüders-like yielding phenomenon at room temperature (RT) and 348 K (75 °C), while it shows continuous yielding at 423 K, 573 K and 673 K (150 °C, 300 °C and 400 °C) deformation. A significant TRIP effect takes place during Lüders-like deformation at RT and 348 K (75 °C) temperatures. Semiquantitative analysis of the TRIP effect on the Lüders-like yield phenomenon proves that a softening effect of the strain energy consumption of strain-induced transformation is mainly responsible for this Lüders-like phenomenon. The TWIP mechanism dominates the 423 K (150 °C) deformation process, while the dislocation glide controls the plasticity at 573 K (300 °C) deformation. The delta-ferrite, as a hard phase in annealed dual-phase steel, greatly affects the mechanical stability of austenite due to the heterogeneous strain distribution between the two phases during deformation. A delta-ferrite-aided TRIP effect, i.e., martensite transformation induced by localized strain concentration of the hard delta-ferrite, is proposed to explain this kind of Lüders-like phenomenon. Moreover, the tensile curve at RT exhibits an upward curved behavior in the middle deformation stage, which is principally attributed to the deformation twinning of austenite retained after Lüders-like deformation. The combination of the TRIP effect during Lüders-like deformation and the subsequent TWIP effect greatly enhances the ductility in this annealed high-manganese dual-phase TRIP/TWIP steel.

  15. Neuron-glia metabolic coupling and plasticity.

    Science.gov (United States)

    Magistretti, Pierre J

    2011-04-01

    The focus of the current research projects in my laboratory revolves around the question of metabolic plasticity of neuron-glia coupling. Our hypothesis is that behavioural conditions, such as for example learning or the sleep-wake cycle, in which synaptic plasticity is well documented, or during specific pathological conditions, are accompanied by changes in the regulation of energy metabolism of astrocytes. We have indeed observed that the 'metabolic profile' of astrocytes is modified during the sleep-wake cycle and during conditions mimicking neuroinflammation in the presence or absence of amyloid-β. The effect of amyloid-β on energy metabolism is dependent on its state of aggregation and on internalization of the peptide by astrocytes. Distinct patterns of metabolic activity could be observed during the learning and recall phases in a spatial learning task. Gene expression analysis in activated areas, notably hippocampous and retrosplenial cortex, demonstrated that the expression levels of several genes implicated in astrocyte-neuron metabolic coupling are enhanced by learning. Regarding metabolic plasticity during the sleep-wake cycle, we have observed that the level of expression of a panel of selected genes, which we know are key for neuron-glia metabolic coupling, is modulated by sleep deprivation.

  16. Multiple determinants controlling activation of yeast replication origins late in S phase.

    Science.gov (United States)

    Friedman, K L; Diller, J D; Ferguson, B M; Nyland, S V; Brewer, B J; Fangman, W L

    1996-07-01

    Analysis of a 131-kb segment of the left arm of yeast chromosome XIV beginning 157 kb from the telomere reveals four highly active origins of replication that initiate replication late in S phase. Previous work has shown that telomeres act as determinants for late origin activation. However, at least two of the chromosome XIV origins maintain their late activation time when located on large circular plasmids, indicating that late replication is independent of telomeres. Analysis of the replication time of plasmid derivatives containing varying amounts of chromosome XIV DNA show that a minimum of three chromosomal elements, distinct from each tested origin, contribute to late activation time. These late determinants are functionally equivalent, because duplication of one set of contributing sequences can compensate for the removal of another set. Furthermore, insertion of an origin that is normally early activated into this domain results in a shift to late activation, suggesting that the chromosome XIV origins are not unique in their ability to respond to the late determinants.

  17. Dispersive solid-phase imprinting of proteins for the production of plastic antibodies

    DEFF Research Database (Denmark)

    Ashley, Jon; Feng, Xiaotong; Halder, Arnab

    2018-01-01

    We describe a novel dispersive solid-phase imprinting technique for the production of nano-sized molecularly imprinted polymers (nanoMIPs) as plastic antibodies. The template was immobilized on in-house synthesized magnetic microspheres instead of conventional glass beads. As a result, high...

  18. Structural conditions of achieving maximum ductility of two-phase Ni-NiO alloys

    International Nuclear Information System (INIS)

    Grabin, V.V.; Dabizha, E.V.; Movchan, B.A.

    1984-01-01

    A study was made on possibility of increasing ductility of two-phase Ni-NiO alloys, proJuced by traditional technology: ingot smelting, rolling and corresponding annealing for production of grain with certain size. The correlation of mechanical properties of Ni-NiO alloys and pure nickel shows that completion of the structural conJition D--lambda (where D - the average grain diameter, lambda - the value of free path between particles) in two-phase alloys enables: to increase the ultimate strength 1.5 times and preserve the basic level of pure nickel plasticity - at 20 deg C; to increase plasticity 1.4-1.5 times with preserved basic level of pure nickel plasticity - at 800 deg C. The conclusions testify to possibility of controlling mechanical properties of two-phase alloys using structural D and lambda parameters It is proposed that creation of structures with more unifor m particle distribution with respect to sizes will the accompanied by further increase of plasticity under D=lambda condition

  19. Space Plastic Recycling System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Techshot's proposed Space Plastic Recycler (SPR) is an automated closed loop plastic recycling system that allows the automated conversion of disposable ISS...

  20. Biphasic somatic A-type K channel downregulation mediates intrinsic plasticity in hippocampal CA1 pyramidal neurons.

    Directory of Open Access Journals (Sweden)

    Sung-Cherl Jung

    2009-08-01

    Full Text Available Since its original description, the induction of synaptic long-term potentiation (LTP has been known to be accompanied by a lasting increase in the intrinsic excitability (intrinsic plasticity of hippocampal neurons. Recent evidence shows that dendritic excitability can be enhanced by an activity-dependent decrease in the activity of A-type K(+ channels. In the present manuscript, we examined the role of A-type K(+ channels in regulating intrinsic excitability of CA1 pyramidal neurons of the hippocampus after synapse-specific LTP induction. In electrophysiological recordings we found that LTP induced a potentiation of excitability which was accompanied by a two-phased change in A-type K(+ channel activity recorded in nucleated patches from organotypic slices of rat hippocampus. Induction of LTP resulted in an immediate but short lasting hyperpolarization of the voltage-dependence of steady-state A-type K(+ channel inactivation along with a progressive, long-lasting decrease in peak A-current density. Blocking clathrin-mediated endocytosis prevented the A-current decrease and most measures of intrinsic plasticity. These results suggest that two temporally distinct but overlapping mechanisms of A-channel downregulation together contribute to the plasticity of intrinsic excitability. Finally we show that intrinsic plasticity resulted in a global enhancement of EPSP-spike coupling.

  1. Two phase modeling of the influence of plastic strain on the magnetic and magnetostrictive behaviors of ferromagnetic materials

    International Nuclear Information System (INIS)

    Hubert, Olivier; Lazreg, Said

    2017-01-01

    A growing interest of automotive industry in the use of high performance steels is observed. These materials are obtained thanks to complex manufacturing processes whose parameters fluctuations lead to strong variations of microstructure and mechanical properties. The on-line magnetic non-destructive monitoring is a relevant response to this problem but it requires fast models sensitive to different parameters of the forming process. The plastic deformation is one of these important parameters. Indeed, ferromagnetic materials are known to be sensitive to stress application and especially to plastic strains. In this paper, a macroscopic approach using the kinematic hardening is proposed to model this behavior, considering a plastic strained material as a two phase system. Relationship between kinematic hardening and residual stress is defined in this framework. Since stress fields are multiaxial, an uniaxial equivalent stress is calculated and introduced inside the so-called magneto-mechanical multidomain modeling to represent the effect of plastic strain. The modeling approach is complemented by many experiments involving magnetic and magnetostrictive measurements. They are carried out with or without applied stress, using a dual-phase steel deformed at different levels. The main interest of this material is that the mechanically hard phase, soft phase and the kinematic hardening can be clearly identified thanks to simple experiments. It is shown how this model can be extended to single phase materials.

  2. Two phase modeling of the influence of plastic strain on the magnetic and magnetostrictive behaviors of ferromagnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, Olivier, E-mail: olivier.hubert@lmt.ens-cachan.fr; Lazreg, Said

    2017-02-15

    A growing interest of automotive industry in the use of high performance steels is observed. These materials are obtained thanks to complex manufacturing processes whose parameters fluctuations lead to strong variations of microstructure and mechanical properties. The on-line magnetic non-destructive monitoring is a relevant response to this problem but it requires fast models sensitive to different parameters of the forming process. The plastic deformation is one of these important parameters. Indeed, ferromagnetic materials are known to be sensitive to stress application and especially to plastic strains. In this paper, a macroscopic approach using the kinematic hardening is proposed to model this behavior, considering a plastic strained material as a two phase system. Relationship between kinematic hardening and residual stress is defined in this framework. Since stress fields are multiaxial, an uniaxial equivalent stress is calculated and introduced inside the so-called magneto-mechanical multidomain modeling to represent the effect of plastic strain. The modeling approach is complemented by many experiments involving magnetic and magnetostrictive measurements. They are carried out with or without applied stress, using a dual-phase steel deformed at different levels. The main interest of this material is that the mechanically hard phase, soft phase and the kinematic hardening can be clearly identified thanks to simple experiments. It is shown how this model can be extended to single phase materials.

  3. Liquid phase solvent bonding of plastic microfluidic devices assisted by retention grooves.

    Science.gov (United States)

    Wan, Alwin M D; Sadri, Amir; Young, Edmond W K

    2015-01-01

    We report a novel method for achieving consistent liquid phase solvent bonding of plastic microfluidic devices via the use of retention grooves at the bonding interface. The grooves are patterned during the regular microfabrication process, and can be placed at the periphery of a device, or surrounding microfluidic features with open ports, where they effectively mitigate solvent evaporation, and thus substantially reduce poor bond coverage. This method is broadly applicable to a variety of plastics and solvents, and produces devices with high bond quality (i.e., coverage, strength, and microfeature fidelity) that are suitable for studies in physics, chemistry, and cell biology at the microscale.

  4. Huginn. A late-phase nuclear emergency exercise

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, Bent (ed.) [Risoe National Lab., Roskilde (Denmark)

    2001-02-01

    The Huginn late-phase exercise was carried out by the NKS/BOK-1.4 project group in the spring 2000. National teams from Denmark, Finland, Norway and Sweden took part in the exercise. The objective of the exercise was to test the ability to calculate the radiological and economical consequences of various agricultural countermeasures following a nuclear accient. This report describes the findings of the four national teams, including the approaches made by the tesms, selection of countermeasures and the results of the cost-benefit analyses that they performed. The methods used and findings by the four teams have been compared and recommendations issued based on the exercise results. (au)

  5. Plasticity induced by phase transformation in steel: experiment vs modeling

    International Nuclear Information System (INIS)

    Tahimi, Abdeladhim

    2011-01-01

    The objectives of this work are: (i) understand the mechanisms and phenomena involved in the plasticity of steels in the presence of a diffusive or martensitic phase transformation. (ii) develop tools for predicting TRIP, which are able to correctly reproduce the macroscopic deformation for cases of complex loading and could also provide information about local elasto-visco-plastic interactions between product and parent phases. To this purpose, new experimental tests are conducted on 35NCD16 steel for austenite to martensite transformation and on 100C6 steel for austenite to pearlite transformation. The elasto viscoplastic properties of austenite and pearlite of the 100C6 steel are characterized through tension compression and relaxation tests. The parameters of macro-homogeneous and crystal-based constitutive laws could then be identified such as to analyse different models with respect to the experimental TRIP: the analytical models of Leblond (1989) and Taleb and Sidoroff (2003) but also, above all, different numerical models which can be distinguished by the prevailing assumptions concerning the local kinetics and the constitutive laws. An extension of the single-grain model dedicated to martensitic transformations developed during the thesis of S. Meftah (2007) is proposed. It consists in introducing the polycrystalline character of the austenite through a process of homogenization based on a self-consistent scheme by calculating the properties of an Equivalent Homogeneous Medium environment (EHM). (author)

  6. Orientational order and rotational relaxation in the plastic crystal phase of tetrahedral molecules.

    Science.gov (United States)

    Rey, Rossend

    2008-01-17

    A methodology recently introduced to describe orientational order in liquid carbon tetrachloride is extended to the plastic crystal phase of XY4 molecules. The notion that liquid and plastic crystal phases are germane regarding orientational order is confirmed for short intermolecular distances but is seen to fail beyond, as long range orientational correlations are found for the simulated solid phase. It is argued that, if real, such a phenomenon may not to be accessible with direct (diffraction) methods due to the high molecular symmetry. This behavior is linked to the existence of preferential orientation with respect to the fcc crystalline network defined by the centers of mass. It is found that the dominant class accounts, at most, for one-third of all configurations, with a feeble dependence on temperature. Finally, the issue of rotational relaxation is also addressed, with an excellent agreement with experimental measures. It is shown that relaxation is nonhomogeneous in the picosecond range, with a slight dispersion of decay times depending on the initial orientational class. The results reported mainly correspond to neopentane over a wide temperature range, although results for carbon tetrachloride are included, as well.

  7. Geological and technological characterization of the Late Jurassic-Early Cretaceous clay deposits (Jebel Ammar, northeastern Tunisia) for ceramic industry

    Science.gov (United States)

    Ben M'barek-Jemaï, Moufida; Sdiri, Ali; Ben Salah, Imed; Ben Aissa, Lassaad; Bouaziz, Samir; Duplay, Joelle

    2017-05-01

    Late Jurassic-Lower Cretaceous clays of the Jebel Ammar study site were used as raw materials for potential applications in ceramic industry. Physico-chemical characterization of the collected samples was performed using atomic absorption spectroscopy, X-ray diffraction, thermogravimetry and dilatometry (Bugot's curve). Geotechnical study was also undertaken by the assessment of plasticity and liquidity limits. It was found that high concentrations of silica, alumina with SiO2/Al2O3 ratio characterized the studied clays; its high amounts of CaO and Fe2O3 in the Late Jurassic clays indicated their calcareous nature. In addition, technological tests indicated moderate to low plasticity values for the Late Jurassic and Lower Cretaceous clays, respectively. Clay fraction (<2 μm) reached 50% of the natural clay in some cases. Mineralogical analysis showed that Jurassic clays were dominated by smectite, illite and kaolinite, as clay mineral species; calcite was the main associated mineral. Lower Cretaceous clays were mainly composed of abundant illite accompanied by well-crystallized smectite and kaolinite. Kaolinite gradually increased upwards, reaching 70% of the total clay fraction (i.e. <2 μm). Quartz, calcite and feldspar were the main non-clay minerals. Based on these analyses, the clays meet technological requirements that would allow their use in the ceramic industry and for the manufacturing of ceramic tiles.

  8. Elastic plastic fracture mechanics

    International Nuclear Information System (INIS)

    Simpson, L.A.

    1978-07-01

    The application of linear elastic fracture mechanics (LEFM) to crack stability in brittle structures is now well understood and widely applied. However, in many structural materials, crack propagation is accompanied by considerable crack-tip plasticity which invalidates the use of LEFM. Thus, present day research in fracture mechanics is aimed at developing parameters for predicting crack propagation under elastic-plastic conditions. These include critical crack-opening-displacement methods, the J integral and R-curve techniques. This report provides an introduction to these concepts and gives some examples of their applications. (author)

  9. Transformation plasticity and hot pressing

    International Nuclear Information System (INIS)

    Chaklader, A.C.D.

    1975-01-01

    The transformation plasticity during the phase transition of quartz to cristobalite, monoclinic reversible tetragonal of zirconia, metakaolin to a spinel phase, and brucite to periclase was investigated by studying their compaction characteristics. Viscous flow was found to be the predominant mechanism of mass transport (after an initial particle rearrangement stage) in the case of quartz to cristobalite phase change where the transformation was associated with the formation of an intermediate amorphous silica phase. The results on the monoclinic reversible tetragonal transformation of zirconia indicated that it is most likely controlled by internal strain induced by the stress associated with the volume change (ΔV/V) and the flow stress of the weaker phase. Particle movement and deformation of the weaker phase (possibly tetragonal) may be the manifestation of this plasticity. The plasticity in the case of metakaolin to a spinel phase appeared to start before the exothermic reaction (generally encountered in a dta plot) and may be diffusion controlled. The plasticity encountered during brucite to periclase transformation may be the combined effect of disintegration of precursor particles, vapor-phase lubrication and some deformability of freshly formed very fine MgO particles

  10. Neuron-glia metabolic coupling and plasticity

    OpenAIRE

    Magistretti PJ

    2011-01-01

    Abstract The focus of the current research projects in my laboratory revolves around the question of metabolic plasticity of neuron glia coupling. Our hypothesis is that behavioural conditions such as for example learning or the sleep wake cycle in which synaptic plasticity is well documented or during specific pathological conditions are accompanied by changes in the regulation of energy metabolism of astrocytes. We have indeed observed that the 'metabolic profile' of astrocytes is modified...

  11. Current challenges for pre-earthquake electromagnetic emissions: shedding light from micro-scale plastic flow, granular packings, phase transitions and self-affinity notion of fracture process

    Science.gov (United States)

    Eftaxias, K.; Potirakis, S. M.

    2013-10-01

    Are there credible electromagnetic (EM) potential earthquake (EQ) precursors? This a question debated in the scientific community and there may be legitimate reasons for the critical views. The negative view concerning the existence of EM potential precursors is enhanced by features that accompany their observation which are considered as paradox ones, namely, these signals: (i) are not observed at the time of EQs occurrence and during the aftershock period, (ii) are not accompanied by large precursory strain changes, (iii) are not accompanied by simultaneous geodetic or seismological precursors and (iv) their traceability is considered problematic. In this work, the detected candidate EM potential precursors are studied through a shift in thinking towards the basic science findings relative to granular packings, micron-scale plastic flow, interface depinning, fracture size effects, concepts drawn from phase transitions, self-affine notion of fracture and faulting process, universal features of fracture surfaces, recent high quality laboratory studies, theoretical models and numerical simulations. We try to contribute to the establishment of strict criteria for the definition of an emerged EM anomaly as a possibly EQ-related one, and to the explanation of potential precursory EM features which have been considered as paradoxes. A three-stage model for EQ generation by means of pre-EQ fracture-induced EM emissions is proposed. The claim that the observed EM potential precursors may permit a real-time and step-by-step monitoring of the EQ generation is tested.

  12. Current challenges for pre-earthquake electromagnetic emissions: shedding light from micro-scale plastic flow, granular packings, phase transitions and self-affinity notion of fracture process

    Directory of Open Access Journals (Sweden)

    K. Eftaxias

    2013-10-01

    Full Text Available Are there credible electromagnetic (EM potential earthquake (EQ precursors? This a question debated in the scientific community and there may be legitimate reasons for the critical views. The negative view concerning the existence of EM potential precursors is enhanced by features that accompany their observation which are considered as paradox ones, namely, these signals: (i are not observed at the time of EQs occurrence and during the aftershock period, (ii are not accompanied by large precursory strain changes, (iii are not accompanied by simultaneous geodetic or seismological precursors and (iv their traceability is considered problematic. In this work, the detected candidate EM potential precursors are studied through a shift in thinking towards the basic science findings relative to granular packings, micron-scale plastic flow, interface depinning, fracture size effects, concepts drawn from phase transitions, self-affine notion of fracture and faulting process, universal features of fracture surfaces, recent high quality laboratory studies, theoretical models and numerical simulations. We try to contribute to the establishment of strict criteria for the definition of an emerged EM anomaly as a possibly EQ-related one, and to the explanation of potential precursory EM features which have been considered as paradoxes. A three-stage model for EQ generation by means of pre-EQ fracture-induced EM emissions is proposed. The claim that the observed EM potential precursors may permit a real-time and step-by-step monitoring of the EQ generation is tested.

  13. MCM-BP regulates unloading of the MCM2–7 helicase in late S phase

    Science.gov (United States)

    Nishiyama, Atsuya; Frappier, Lori; Méchali, Marcel

    2011-01-01

    Origins of DNA replication are licensed by recruiting MCM2–7 to assemble the prereplicative complex (pre-RC). How MCM2–7 is inactivated or removed from chromatin at the end of S phase is still unclear. Here, we show that MCM-BP can disassemble the MCM2–7 complex and might function as an unloader of MCM2–7 from chromatin. In Xenopus egg extracts, MCM-BP exists in a stable complex with MCM7, but is not associated with the MCM2–7 hexameric complex. MCM-BP accumulates in nuclei in late S phase, well after the loading of MCM2–7 onto chromatin. MCM-BP immunodepletion in Xenopus egg extracts inhibits replication-dependent MCM dissociation without affecting pre-RC formation and DNA replication. When excess MCM-BP is incubated with Xenopus egg extracts or immunopurified MCM2–7, it binds to MCM proteins and promotes disassembly of the MCM2–7 complex. Recombinant MCM-BP also releases MCM2–7 from isolated late-S-phase chromatin, but this activity is abolished when DNA replication is blocked. MCM-BP silencing in human cells also delays MCM dissociation in late S phase. We propose that MCM-BP plays a key role in the mechanism by which pre-RC is cleared from replicated DNA in vertebrate cells. PMID:21196493

  14. Possible contributions of a novel form of synaptic plasticity in Aplysia to reward, memory, and their dysfunctions in mammalian brain.

    Science.gov (United States)

    Hawkins, Robert D

    2013-09-18

    Recent studies in Aplysia have identified a new variation of synaptic plasticity in which modulatory transmitters enhance spontaneous release of glutamate, which then acts on postsynaptic receptors to recruit mechanisms of intermediate- and long-term plasticity. In this review I suggest the hypothesis that similar plasticity occurs in mammals, where it may contribute to reward, memory, and their dysfunctions in several psychiatric disorders. In Aplysia, spontaneous release is enhanced by activation of presynaptic serotonin receptors, but presynaptic D1 dopamine receptors or nicotinic acetylcholine receptors could play a similar role in mammals. Those receptors enhance spontaneous release of glutamate in hippocampus, entorhinal cortex, prefrontal cortex, ventral tegmental area, and nucleus accumbens. In all of those brain areas, glutamate can activate postsynaptic receptors to elevate Ca(2+) and engage mechanisms of early-phase long-term potentiation (LTP), including AMPA receptor insertion, and of late-phase LTP, including protein synthesis and growth. Thus, presynaptic receptors and spontaneous release may contribute to postsynaptic mechanisms of plasticity in brain regions involved in reward and memory, and could play roles in disorders that affect plasticity in those regions, including addiction, Alzheimer's disease, schizophrenia, and attention deficit hyperactivity disorder (ADHD).

  15. Plasticity-induced characteristic changes of pattern dynamics and the related phase transitions in small-world neuronal networks

    International Nuclear Information System (INIS)

    Huang Xu-Hui; Hu Gang

    2014-01-01

    Phase transitions widely exist in nature and occur when some control parameters are changed. In neural systems, their macroscopic states are represented by the activity states of neuron populations, and phase transitions between different activity states are closely related to corresponding functions in the brain. In particular, phase transitions to some rhythmic synchronous firing states play significant roles on diverse brain functions and disfunctions, such as encoding rhythmical external stimuli, epileptic seizure, etc. However, in previous studies, phase transitions in neuronal networks are almost driven by network parameters (e.g., external stimuli), and there has been no investigation about the transitions between typical activity states of neuronal networks in a self-organized way by applying plastic connection weights. In this paper, we discuss phase transitions in electrically coupled and lattice-based small-world neuronal networks (LBSW networks) under spike-timing-dependent plasticity (STDP). By applying STDP on all electrical synapses, various known and novel phase transitions could emerge in LBSW networks, particularly, the phenomenon of self-organized phase transitions (SOPTs): repeated transitions between synchronous and asynchronous firing states. We further explore the mechanics generating SOPTs on the basis of synaptic weight dynamics. (interdisciplinary physics and related areas of science and technology)

  16. Liver CT for vascular mapping during radioembolisation workup : comparison of an early and late arterial phase protocol

    NARCIS (Netherlands)

    van den Hoven, Andor F; Braat, Manon N G J A; Prince, Jip F; van Doormaal, Pieter J; van Leeuwen, Maarten S; Lam, Marnix G E H; van den Bosch, Maurice A A J

    OBJECTIVES: To compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols. METHODS: 100 consecutive patients who underwent liver CT between May 2012-January 2015 with early or late arterial

  17. Physiotherapeutic approach on the late phase of chikungunya: a case report

    Directory of Open Access Journals (Sweden)

    Aileciram Monialy Barros Marinho Ribeiro

    Full Text Available Abstract Introduction: in April of 2016, the epidemiological bulletin reported 39,017 suspected cases of chikungunya fever in Brazil. The main symptoms of the disease in the acute phase are: high fever, polyarthralgia, back pain, headache and fatigue; while in the late phase present polyarthralgia or musculoskeletal pain which often has prolonged duration. Description: in the late phase, the patient presented complaints mainly of: severe pain on the ankle joints wrists, elbows and shoulders. The medical handling consisted of continuous ultrasound sessions with the frequency of 1 MHz. The infrared laser with a dosage of 4J and 3s per point; TENS-burst with a pulse width of 250 us and the frequency of 2Hz, carried out for 10 days. The physiotherapeutic treatment proposal was an innovation, however there are no medical literatures for completementary medication for the treatment which could reduce the use of analgesics and could cause prolonged comfort to the patient ratified by EVA and the SF-36. Discussion: the use of ultrasound and low intensity laser are performed on the signs of chronic articular treatment in order to reduce inflammation, pain and joint stiffness. Therefore, a remarkable reduction of the algic state and the improvement of the patient's life along the r ten consecutive sessions of a proposed protocol in this study, thus there is a need for further researches on this issue so it is possible to perform a medical handling based on evidences on the theme.

  18. Plasticity, Variability and Age in Second Language Acquisition and Bilingualism.

    Science.gov (United States)

    Birdsong, David

    2018-01-01

    Much of what is known about the outcome of second language acquisition and bilingualism can be summarized in terms of inter-individual variability, plasticity and age. The present review looks at variability and plasticity with respect to their underlying sources, and at age as a modulating factor in variability and plasticity. In this context we consider critical period effects vs. bilingualism effects, early and late bilingualism, nativelike and non-nativelike L2 attainment, cognitive aging, individual differences in learning, and linguistic dominance in bilingualism. Non-uniformity is an inherent characteristic of both early and late bilingualism. This review shows how plasticity and age connect with biological and experiential sources of variability, and underscores the value of research that reveals and explains variability. In these ways the review suggests how plasticity, variability and age conspire to frame fundamental research issues in L2 acquisition and bilingualism, and provides points of reference for discussion of the present Frontiers in Psychology Research Topic.

  19. Molecular reorientations in a substance with liquid-crystalline and plastic-crystalline phases

    International Nuclear Information System (INIS)

    Nguyen, Xuan Phuc.

    1986-05-01

    Results of dielectric relaxation (DR), quasielastic neutron scattering (QNS), far infrared absorption (FIR), proton magnetic resonance (PMR), differential scanning calorimetry (DSC) and preliminary X-ray diffraction measurements on the di-n-pentyloxyazoxybenzene (5.OAOB) are presented. The measurements carried out by all these methods showed that 5.OAOB exhibits a nontypical for liquid-crystalline materials phase diagram. It has two mesophases: a nematic (N) and an ''intermediate'' crystalline phase just below it. A complex interpretation of results obtained is given. All suggestions concerning the character of reorientational motions of the molecule as a whole as well as of its segments in mesomorphic phases are analyzed. From comparison of the DR and QNS studies one can conclude that in the N phase the molecule as a whole performs rotational diffusion around the long axis (τ DR ∼ 100 ps) and at the same time the two moieties perform faster independent reorientations around N - benzene rings bonds withτ QNS ∼ 5 ps. On the basis of various experimental data it is shown that the CrI phase is a plastic-crystalline phase for which the molecule and its segments perform fast stochastic unaxial reorientations. This is the first case where the existence of such a phase in liquid-crystalline materials has been experimentally confirmed. (author)

  20. Plastic debris retention and exportation by a mangrove forest patch

    International Nuclear Information System (INIS)

    Ivar do Sul, Juliana A.; Costa, Monica F.; Silva-Cavalcanti, Jacqueline S.; Araújo, Maria Christina B.

    2014-01-01

    Highlights: • Estuaries and mangrove forests are rarely studied for marine plastic debris loads. • Types of plastic items and mangrove forest habitats determine the potential of debris retention. • Mangrove habitats are temporary sinks of plastic debris from river and marine origins. • Plastics rapidly accumulate in mangrove forest, but are exported slowly. • Fauna and fishers using mangrove forest habitats are at risk of interaction with plastic debris. -- Abstract: An experiment observed the behavior of selected tagged plastic items deliberately released in different habitats of a tropical mangrove forest in NE Brazil in late rainy (September) and late dry (March) seasons. Significant differences were not reported among seasons. However, marine debris retention varied among habitats, according to characteristics such as hydrodynamic (i.e., flow rates and volume transported) and relative vegetation (Rhizophora mangle) height and density. The highest grounds retained significantly more items when compared to the borders of the river and the tidal creek. Among the used tagged items, PET bottles were more observed and margarine tubs were less observed, being easily transported to adjacent habitats. Plastic bags were the items most retained near the releasing site. The balance between items retained and items lost was positive, demonstrating that mangrove forests tend to retain plastic marine debris for long periods (months-years)

  1. Liver CT for vascular mapping during radioembolisation workup: comparison of an early and late arterial phase protocol

    Energy Technology Data Exchange (ETDEWEB)

    Hoven, Andor F. van den; Braat, Manon N.G.J.A.; Prince, Jip F.; Doormaal, Pieter J. van; Leeuwen, Maarten S. van; Lam, Marnix G.E.H.; Bosch, Maurice A.A.J. van den [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands)

    2017-01-15

    To compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols. 100 consecutive patients who underwent liver CT between May 2012-January 2015 with early or late arterial phase protocol (n = 50 each, 10- vs. 20-s post-threshold delay) were included. RGA/A4 origin detection rates, assessed by two raters, and contrast-to-noise ratio (CNR) of the hepatic artery relative to the portal vein were compared between the protocols. The first-second rater scored the RGA origin as visible in 58-65 % (specific proportion of agreement 82 %, κ = 0.62); A4 origin in 96-89 % (94 %, κ = 0.54). Thirty-six percent of RGA origins not detectable by DSA were identified on CT. Origin detection rates were not significantly different for early/late arterial phases. Mean CNR was higher in the early arterial phase protocol (1.7 vs. 1.2, p < 0.001). A 10-s delay arterial phase CT protocol does not significantly improve detection of small intra- and extrahepatic branches. RGA origin detection requires further optimization, whereas A4/MHA origin detection is adequate, with good inter-rater reproducibility. CT remains important for preprocedural planning, because it may reveal arterial anatomy not discernible on DSA. (orig.)

  2. Age-related changes in spatiotemporal characteristics of gait accompany ongoing lower limb linear growth in late childhood and early adolescence.

    Science.gov (United States)

    Froehle, Andrew W; Nahhas, Ramzi W; Sherwood, Richard J; Duren, Dana L

    2013-05-01

    Walking gait is generally held to reach maturity, including walking at adult-like velocities, by 7-8 years of age. Lower limb length, however, is a major determinant of gait, and continues to increase until 13-15 years of age. This study used a sample from the Fels Longitudinal Study (ages 8-30 years) to test the hypothesis that walking with adult-like velocity on immature lower limbs results in the retention of immature gait characteristics during late childhood and early adolescence. There was no relationship between walking velocity and age in this sample, whereas the lower limb continued to grow, reaching maturity at 13.2 years in females and 15.6 years in males. Piecewise linear mixed models regression analysis revealed significant age-related trends in normalized cadence, initial double support time, single support time, base of support, and normalized step length in both sexes. Each trend reached its own, variable-specific age at maturity, after which the gait variables' relationships with age reached plateaus and did not differ significantly from zero. Offsets in ages at maturity occurred among the gait variables, and between the gait variables and lower limb length. The sexes also differed in their patterns of maturation. Generally, however, immature walkers of both sexes took more frequent and relatively longer steps than did mature walkers. These results support the hypothesis that maturational changes in gait accompany ongoing lower limb growth, with implications for diagnosing, preventing, and treating movement-related disorders and injuries during late childhood and early adolescence. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. The Microstructure Evolution of Dual-Phase Pipeline Steel with Plastic Deformation at Different Strain Rates

    Science.gov (United States)

    Ji, L. K.; Xu, T.; Zhang, J. M.; Wang, H. T.; Tong, M. X.; Zhu, R. H.; Zhou, G. S.

    2017-07-01

    Tensile properties of the high-deformability dual-phase ferrite-bainite X70 pipeline steel have been investigated at room temperature under the strain rates of 2.5 × 10-5, 1.25 × 10-4, 2.5 × 10-3, and 1.25 × 10-2 s-1. The microstructures at different amount of plastic deformation were examined by using scanning and transmission electron microscopy. Generally, the ductility of typical body-centered cubic steels is reduced when its stain rate increases. However, we observed a different ductility dependence on strain rates in the dual-phase X70 pipeline steel. The uniform elongation (UEL%) and elongation to fracture (EL%) at the strain rate of 2.5 × 10-3 s-1 increase about 54 and 74%, respectively, compared to those at 2.5 × 10-5 s-1. The UEL% and EL% reach to their maximum at the strain rate of 2.5 × 10-3 s-1. This phenomenon was explained by the observed grain structures and dislocation configurations. Whether or not the ductility can be enhanced with increasing strain rates depends on the competition between the homogenization of plastic deformation among the microconstituents (ultra-fine ferrite grains, relatively coarse ferrite grains as well as bainite) and the progress of cracks formed as a consequence of localized inconsistent plastic deformation.

  4. Progressive deformation of ultramafic rocks accompanied with deflection of layered structure and mylonitization culminating into a pseudotachylyte-bearing seismogenic fault - a field evidence of plastic instability

    Science.gov (United States)

    Ueda, T.; Obata, M.

    2011-12-01

    Plastic instability leading to rupture nucleation and propagetion (e.g. Hobbs et al.1986, Kelemen and Hirth, 2007) is an attractive hypothesis for deep earthquakes but lacked clear field evidences. 1D across-fault shear localization observed in some places (e.g. Jin et al.1998) is not clear if the deformation is directly related with seismicity. We present a clear field evidence of plastic instability as guided by pyroxenite/peridotite layering deflection structure (hereafter called LD structure, see figure) accompanied with mylonitization in spinel(Sp)-peridotite facies (P>~1GPa) in Balmuccia peridotite, Ivrea-Verbano Zone, Italy. The studied area contains abundant PST-bearing faults and N-S trending primary pyroxenite layers. Many faults in the area cut pyroxenite layers, but LD structure is found only in one place presented here. Many PSTs in the area have been (re)crystallized in Sp-peridotite facies, and have typically ultramylonitic texture (Ueda et al., 2008) with some injection veins. The fault with LD structure is situated in a fault system, which has two dominant attitudes with regional N-S extension. The shear strain of LD structure measured on outcrop surface is ~2.0. Near the fault, elongated Opx porphyroclasts (ellipses in figure) oblique to local layering are visible in peridotite. The dominant deformation textures are dynamic recrystallization in peridotite and kinking or undulatory extinction in pyroxenite. The mineral assemblages of the mylonite neoblast in the peridotite and the pyroxenite are Ol+Opx+Cpx+Sp+hornblende(Hbl), Cpx+Opx+Sp, respectively. Hbl typically occur only in neoblast. In the vicinity (several hundreds of micron) of the fault, dolomite(Dol) also occur in equilibrium with the assemblage above. The recrystallized grain sizes are 20-50 microns in peridotite and 10-30 microns in pyroxenite. The rarity of LD structure is consistent with general conception that deformation processes which lead to dynamic rupture initiation ought to be

  5. Compensatory plasticity: time matters

    Directory of Open Access Journals (Sweden)

    Latifa eLazzouni

    2014-06-01

    Full Text Available Plasticity in the human and animal brain is the rule, the base for development, and the way to deal effectively with the environment for making the most efficient use of all the senses. When the brain is deprived of one sensory modality, plasticity becomes compensatory: the exception that invalidates the general loss hypothesis giving the opportunity of effective change. Sensory deprivation comes with massive alterations in brain structure and function, behavioural outcomes, and neural interactions. Blind individuals do as good as the sighted and even more, show superior abilities in auditory, tactile and olfactory processing. This behavioural enhancement is accompanied with changes in occipital cortex function, where visual areas at different levels become responsive to non-visual information. The intact senses are in general used more efficiently in the blind but are also used more exclusively. New findings are disentangling these two aspects of compensatory plasticity. What is due to visual deprivation and what is dependent on the extended use of spared modalities? The latter seems to contribute highly to compensatory changes in the congenitally blind. Short term deprivation through the use of blindfolds shows that cortical excitability of the visual cortex is likely to show rapid modulatory changes after few minutes of light deprivation and therefore changes are possible in adulthood. However, reorganization remains more pronounced in the congenitally blind. Cortico-cortical pathways between visual areas and the areas of preserved sensory modalities are inhibited in the presence of vision, but are unmasked after loss of vision or blindfolding as a mechanism likely to drive cross-modal information to the deafferented visual cortex. Plasticity in the blind is also accompanied with neurochemical and morphological changes; both intrinsic connectivity and functional coupling at rest are altered but are likewise dependent on different sensory

  6. Nano-plastics in the aquatic environment.

    Science.gov (United States)

    Mattsson, K; Hansson, L-A; Cedervall, T

    2015-10-01

    The amount of plastics released to the environment in modern days has increased substantially since the development of modern plastics in the early 1900s. As a result, concerns have been raised by the public about the impact of plastics on nature and on, specifically, aquatic wildlife. Lately, much attention has been paid to macro- and micro-sized plastics and their impact on aquatic organisms. However, micro-sized plastics degrade subsequently into nano-sizes whereas nano-sized particles may be released directly into nature. Such particles have a different impact on aquatic organisms than larger pieces of plastic due to their small size, high surface curvature, and large surface area. This review describes the possible sources of nano-sized plastic, its distribution and behavior in nature, the impact of nano-sized plastic on the well-being of aquatic organisms, and the difference of impact between nano- and micro-sized particles. We also identify research areas which urgently need more attention and suggest experimental methods to obtain useful data.

  7. Appreciation of Triaxiality Influence in Plastic Deformation Accompanying Ductile Rupture

    Science.gov (United States)

    Coseru, Ancuta-Ioana; Zichil, Valentin; Lupascu, Stefan

    2017-12-01

    In this paper, the authors propose a studying method for the deformation that appears before crack of ductile materials using the Lode parameter determined by the numerical calculation applied on simple models, verified in previous studies. In order to highlight the influence of the Lode parameter, the tests were performed at simple but also at compound tests. The necessity of these studies lies in the fact that the acknowledged models (the use of the integral J, the critical stress intensity factor Kc or the CPCD method) do not fully explain the phenomenon of deformation before breaking the elasto-plastic materials. The tests were imagined under the form of sets. Each set of tests was performed on smooth specimens and on specimens with a notch radius of 0.5, 2, 4 and 10 mm. Also, each set of tests was performed for pure tensile and combined tensile-torque test.

  8. Quantitative Analysis of Bisphenol A Leached from Household Plastics by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (SPME-GC-MS)

    Science.gov (United States)

    Johnson, Bettie Obi; Burke, Fernanda M.; Harrison, Rebecca; Burdette, Samantha

    2012-01-01

    The measurement of trace levels of bisphenol A (BPA) leached out of household plastics using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) is reported here. BPA is an endocrine-disrupting compound used in the industrial manufacture of polycarbonate plastic bottles and epoxy resin can liners. This experiment…

  9. A Cosserat crystal plasticity and phase field theory for grain boundary migration

    Science.gov (United States)

    Ask, Anna; Forest, Samuel; Appolaire, Benoit; Ammar, Kais; Salman, Oguz Umut

    2018-06-01

    The microstructure evolution due to thermomechanical treatment of metals can largely be described by viscoplastic deformation, nucleation and grain growth. These processes take place over different length and time scales which present significant challenges when formulating simulation models. In particular, no overall unified field framework exists to model concurrent viscoplastic deformation and recrystallization and grain growth in metal polycrystals. In this work a thermodynamically consistent diffuse interface framework incorporating crystal viscoplasticity and grain boundary migration is elaborated. The Kobayashi-Warren-Carter (KWC) phase field model is extended to incorporate the full mechanical coupling with material and lattice rotations and evolution of dislocation densities. The Cosserat crystal plasticity theory is shown to be the appropriate framework to formulate the coupling between phase field and mechanics with proper distinction between bulk and grain boundary behaviour.

  10. Interphase and intergranular stress generation in composites exhibiting plasticity in both phases

    International Nuclear Information System (INIS)

    Daymond, Mark R; Hartig, Christian; Mecking, Heinrich

    2005-01-01

    The internal stress state of Fe-Cu composites has been measured by in situ deformation studies using neutron diffraction. A range of volume fractions from 17% Fe to 83% Fe (remainder Cu) have been investigated. Both phase specific and grain family specific elastic strains have been determined. The results are compared with predictions from a multiphase elasto-plastic self-consistent model, and are found to be in good agreement. The selection of parameters used in the model to improve agreement between experimental and predicted results is suggested to be due to changing geometrical constraint

  11. Composite of wood-plastic and micro-encapsulated phase change material (MEPCM) used for thermal energy storage

    International Nuclear Information System (INIS)

    Jamekhorshid, A.; Sadrameli, S.M.; Barzin, R.; Farid, M.M.

    2017-01-01

    Highlights: • A composite of wood–plastic-MEPCM has been produced. • Compression molding has been used for the composite preparation. • Thermal and properties were investigated using DSC analysis and cycling test. • Leakage test has been performed for the encapsulated PCM. • The composites can be used as a building material for thermal energy management. - Abstract: Application of phase change materials (PCMs) in lightweight building is growing due to the high latent heat of fusion of PCMs and their ability to control temperature by absorbing and releasing heat efficiently. Wood-plastic composites (WPC) are materials used in the interior parts of buildings that have improved properties compared to conventional materials. However, these materials have low energy storage capacity, which can be improved by incorporating PCM in them. Leakage of PCM is a major obstacle to the industrial applications, which can be solved through the use of microencapsulated PCM (MEPCM). This paper presents the performance tests conducted for a composite of wood-plastic-MEPCM for using in buildings for thermal storage. The wood-plastic-MEPCM composites were produced in this project using compression molding and their thermal and mechanical properties were investigated using DSC analysis, cycling test, leakage test, and three point bending analysis. The results showed that there is no leakage of PCM during phase change. The results also indicated that the composite has reasonable thermal properties, but its mechanical properties need to be improved by increasing the pressure during the molding process or by using extrusion method. The produced composites can be used as a building material for thermal energy management of building.

  12. A modified Gurson-type plasticity model at finite strains: formulation, numerical analysis and phase-field coupling

    Science.gov (United States)

    Aldakheel, Fadi; Wriggers, Peter; Miehe, Christian

    2017-12-01

    The modeling of failure in ductile materials must account for complex phenomena at the micro-scale, such as nucleation, growth and coalescence of micro-voids, as well as the final rupture at the macro-scale, as rooted in the work of Gurson (J Eng Mater Technol 99:2-15, 1977). Within a top-down viewpoint, this can be achieved by the combination of a micro-structure-informed elastic-plastic model for a porous medium with a concept for the modeling of macroscopic crack discontinuities. The modeling of macroscopic cracks can be achieved in a convenient way by recently developed continuum phase field approaches to fracture, which are based on the regularization of sharp crack discontinuities, see Miehe et al. (Comput Methods Appl Mech Eng 294:486-522, 2015). This avoids the use of complex discretization methods for crack discontinuities, and can account for complex crack patterns. In this work, we develop a new theoretical and computational framework for the phase field modeling of ductile fracture in conventional elastic-plastic solids under finite strain deformation. It combines modified structures of Gurson-Tvergaard-Needelman GTN-type plasticity model outlined in Tvergaard and Needleman (Acta Metall 32:157-169, 1984) and Nahshon and Hutchinson (Eur J Mech A Solids 27:1-17, 2008) with a new evolution equation for the crack phase field. An important aspect of this work is the development of a robust Explicit-Implicit numerical integration scheme for the highly nonlinear rate equations of the enhanced GTN model, resulting with a low computational cost strategy. The performance of the formulation is underlined by means of some representative examples, including the development of the experimentally observed cup-cone failure mechanism.

  13. Evaluation of the renal venous system on late arterial and venous phase images with MDCT angiography in potential living laparoscopic renal donors

    International Nuclear Information System (INIS)

    Kawamoto, S.; Lawler, L.P.; Fishman, E.K.

    2005-01-01

    Objective: The objective of our study was to assess whether both renal arteries and renal veins can be evaluated using single-phase MDCT data sets alone to eliminate the need for both arterial and venous phase data sets. Materials and methods: One hundred consecutive potential living renal donors who underwent 4- MDCT were evaluated. CT was performed with 120 mL of IV contrast material at an injection rate of 3 mL/sec. Both late arterial and venous phase acquisitions were obtained at 25 and 55 sec from the start of IV contrast injection, respectively. The number of the right and left renal veins and its anatomic variations were assessed by two reviewers. Late arterial phase images were evaluated initially, and then venous phase images were analyzed to assess opacification of the renal vein and to see whether venous phase data sets changed or added information about the venous anatomy as seen on late arterial phase images. Results: The retroaortic left renal vein was found in two subjects, and the circumaortic left renal vein was detected in three subjects. The renal veins were adequately opacified on late arterial phase images in all subjects. There were six subjects who had a normal left renal vein with a small posterior branch coursing posterior to the aorta and draining into the inferior vena cava, which were difficult to differentiate from the lumbar vein or ascending lumbar vein; in three of these six subjects, the small posterior branch was opacified only on venous phase images. Conclusion: Late arterial phase images obtained at 25 sec after the start of contrast injection can reveal the renal vein anatomy except for a small posterior branch of the left renal vein difficult to differentiate from the lumbar or ascending lumbar vein, as seen in three subjects. The data suggest that venous phase imaging is not necessary for the evaluation of renal vein anatomy. (author)

  14. Evaluation of the renal venous system on late arterial and venous phase images with MDCT angiography in potential living laparoscopic renal donors

    Energy Technology Data Exchange (ETDEWEB)

    Kawamoto, S.; Lawler, L.P.; Fishman, E.K. [Johns Hopkins Hospital, Baltimore, MD (United States). The Russell H. Morgan Department of Radiology and Radiological Science

    2005-03-15

    Objective: The objective of our study was to assess whether both renal arteries and renal veins can be evaluated using single-phase MDCT data sets alone to eliminate the need for both arterial and venous phase data sets. Materials and methods: One hundred consecutive potential living renal donors who underwent 4- MDCT were evaluated. CT was performed with 120 mL of IV contrast material at an injection rate of 3 mL/sec. Both late arterial and venous phase acquisitions were obtained at 25 and 55 sec from the start of IV contrast injection, respectively. The number of the right and left renal veins and its anatomic variations were assessed by two reviewers. Late arterial phase images were evaluated initially, and then venous phase images were analyzed to assess opacification of the renal vein and to see whether venous phase data sets changed or added information about the venous anatomy as seen on late arterial phase images. Results: The retroaortic left renal vein was found in two subjects, and the circumaortic left renal vein was detected in three subjects. The renal veins were adequately opacified on late arterial phase images in all subjects. There were six subjects who had a normal left renal vein with a small posterior branch coursing posterior to the aorta and draining into the inferior vena cava, which were difficult to differentiate from the lumbar vein or ascending lumbar vein; in three of these six subjects, the small posterior branch was opacified only on venous phase images. Conclusion: Late arterial phase images obtained at 25 sec after the start of contrast injection can reveal the renal vein anatomy except for a small posterior branch of the left renal vein difficult to differentiate from the lumbar or ascending lumbar vein, as seen in three subjects. The data suggest that venous phase imaging is not necessary for the evaluation of renal vein anatomy. (author)

  15. Serum IgE and IgG4 against muscle larva excretory-secretory products during the early and late phases of human trichinellosis.

    Science.gov (United States)

    Calcagno, Marcela A; Forastiero, María A; Saracino, María P; Vila, Cecilia C; Venturiello, Stella M

    2017-11-01

    In human trichinellosis, the relevance of the presence and persistence of specific serum IgE and IgG4 during the early and late phases of infection is still controversial.The aim of this work was to determine the percentage of human sera presenting IgE and IgG4 against Trichinella spiralis muscle larvae excretory-secretory products as well as their levels during the early and late phases of the infection. The antigen recognition pattern by serum total immunoglobulins (IgGAM), IgE, and IgG4 was assessed over time. Serum samples during early and late phases were analyzed by ELISA and immunoelectrotransfer blot (IETB).Results showed that (a)-IgE and IgG4 are present at constant levels in both phases; (b)-IgE recognized the glycoproteins of ~ 45 and ~ 55 kDa and IgG4 only the ~ 45 kDa; (c)-in the late phase, the percentage of specific IgE positive sera was higher than that of specific IgG4 by IETB; while in serum samples taken during the early phase, no differences were found between both isotypes; (d)-both isotypes displayed different glycoprotein recognition patterns: the pattern corresponding to IgE was coincident with that of IgGAM, comprising seven glycoproteins (ranging from ~ 116 to ~ 29 kDa), whereas IgG4 revealed four glycoproteins (ranging from ~ 97 to ~ 45 kDa), showing a different sera recognition percentage depending on the phase studied.In conclusion, IgE and IgG4 cannot be considered exclusive isotypes of neither the early nor the late phase of infection and they are as useful as the detection of total antibodies in the early diagnosis.

  16. Social Isolation During Adolescence Strengthens Retention of Fear Memories and Facilitates Induction of Late-Phase Long-Term Potentiation.

    Science.gov (United States)

    Liu, Ji-Hong; You, Qiang-Long; Wei, Mei-Dan; Wang, Qian; Luo, Zheng-Yi; Lin, Song; Huang, Lang; Li, Shu-Ji; Li, Xiao-Wen; Gao, Tian-Ming

    2015-12-01

    Social isolation during the vulnerable period of adolescence produces emotional dysregulation that often manifests as abnormal behavior in adulthood. The enduring consequence of isolation might be caused by a weakened ability to forget unpleasant memories. However, it remains unclear whether isolation affects unpleasant memories. To address this, we used a model of associative learning to induce the fear memories and evaluated the influence of isolation mice during adolescence on the subsequent retention of fear memories and its underlying cellular mechanisms. Following adolescent social isolation, we found that mice decreased their social interaction time and had an increase in anxiety-related behavior. Interestingly, when we assessed memory retention, we found that isolated mice were unable to forget aversive memories when tested 4 weeks after the original event. Consistent with this, we observed that a single train of high-frequency stimulation (HFS) enabled a late-phase long-term potentiation (L-LTP) in the hippocampal CA1 region of isolated mice, whereas only an early-phase LTP was observed with the same stimulation in the control mice. Social isolation during adolescence also increased brain-derived neurotrophic factor (BDNF) expression in the hippocampus, and application of a tropomyosin-related kinase B (TrkB) receptor inhibitor ameliorated the facilitated L-LTP seen after isolation. Together, our results suggest that adolescent isolation may result in mental disorders during adulthood and that this may stem from an inability to forget the unpleasant memories via BDNF-mediated synaptic plasticity. These findings may give us a new strategy to prevent mental disorders caused by persistent unpleasant memories.

  17. Hippocampal Structural Plasticity Accompanies the Resulting Contextual Fear Memory Following Stress and Fear Conditioning

    Science.gov (United States)

    Giachero, Marcelo; Calfa, Gaston D.; Molina, Victor A.

    2013-01-01

    The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to…

  18. OWN EXPERIENCE OF LASER THERAPY FOR THE PREVENTION AND TREATMENT OF EARLY AND LATE RADIATION-INDUCED SKIN INJURIES IN PATIENTS WITH BREAST CANCER AFTER SIMULTANEOUS RECONSTRUCTIVE PLASTIC SURGERY

    Directory of Open Access Journals (Sweden)

    S. I. Tkachev

    2017-01-01

    Full Text Available Low-energy laser radiation has a good anti-inflammatory and stimulating effect on the damaged tissues; therefore, it can be used for the prevention and treatment of both early and late radiation-induced skin injuries in patients receiving radiotherapy. So far, the effect of low-energy laser radiation in the prevention of radiation-induced skin damage remains poorly understood. This article presents a brief overview of the results obtained in the latest foreign studies as well as own experience of laser therapy for the prevention and treatment of both early and late radiation-induced skin injuries in patients with breast cancer after simultaneous reconstructive plastic surgery.

  19. Global profiling of DNA replication timing and efficiency reveals that efficient replication/firing occurs late during S-phase in S. pombe.

    Directory of Open Access Journals (Sweden)

    Majid Eshaghi

    Full Text Available BACKGROUND: During S. pombe S-phase, initiation of DNA replication occurs at multiple sites (origins that are enriched with AT-rich sequences, at various times. Current studies of genome-wide DNA replication profiles have focused on the DNA replication timing and origin location. However, the replication and/or firing efficiency of the individual origins on the genomic scale remain unclear. METHODOLOGY/PRINCIPAL FINDINGS: Using the genome-wide ORF-specific DNA microarray analysis, we show that in S. pombe, individual origins fire with varying efficiencies and at different times during S-phase. The increase in DNA copy number plotted as a function of time is approximated to the near-sigmoidal model, when considering the replication start and end timings at individual loci in cells released from HU-arrest. Replication efficiencies differ from origin to origin, depending on the origin's firing efficiency. We have found that DNA replication is inefficient early in S-phase, due to inefficient firing at origins. Efficient replication occurs later, attributed to efficient but late-firing origins. Furthermore, profiles of replication timing in cds1Delta cells are abnormal, due to the failure in resuming replication at the collapsed forks. The majority of the inefficient origins, but not the efficient ones, are found to fire in cds1Delta cells after HU removal, owing to the firing at the remaining unused (inefficient origins during HU treatment. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that efficient DNA replication/firing occurs late in S-phase progression in cells after HU removal, due to efficient late-firing origins. Additionally, checkpoint kinase Cds1p is required for maintaining the efficient replication/firing late in S-phase. We further propose that efficient late-firing origins are essential for ensuring completion of DNA duplication by the end of S-phase.

  20. Temporal Dynamics of Bacterial and Fungal Colonization on Plastic Debris in the North Sea.

    Science.gov (United States)

    De Tender, Caroline; Devriese, Lisa I; Haegeman, Annelies; Maes, Sara; Vangeyte, Jürgen; Cattrijsse, André; Dawyndt, Peter; Ruttink, Tom

    2017-07-05

    Despite growing evidence that biofilm formation on plastic debris in the marine environment may be essential for its biodegradation, the underlying processes have yet to be fully understood. Thus, far, bacterial biofilm formation had only been studied after short-term exposure or on floating plastic, yet a prominent share of plastic litter accumulates on the seafloor. In this study, we explored the taxonomic composition of bacterial and fungal communities on polyethylene plastic sheets and dolly ropes during long-term exposure on the seafloor, both at a harbor and an offshore location in the Belgian part of the North Sea. We reconstructed the sequence of events during biofilm formation on plastic in the harbor environment and identified a core bacteriome and subsets of bacterial indicator species for early, intermediate, and late stages of biofilm formation. Additionally, by implementing ITS2 metabarcoding on plastic debris, we identified and characterized for the first time fungal genera on plastic debris. Surprisingly, none of the plastics exposed to offshore conditions displayed the typical signature of a late stage biofilm, suggesting that biofilm formation is severely hampered in the natural environment where most plastic debris accumulates.

  1. Preparation of multishell ICF target plastic-foam cushion materials by thermally induced phase-inversion processes

    International Nuclear Information System (INIS)

    Young, A.T.; Moreno, D.K.; Marsters, R.G.

    1981-01-01

    Homogenous, low-density plastic foams for ICF targets have been prepared by thermally induced phase inversion processes. Uniform, open cell foams have been obtained by the rapid freezing of water solutions of modified cellulose polymers with densities in the range of 5 mg/cm 3 to 0.7 mg/cm 3 and respective average cell sizes of 2 to 40 micrometers. In addition, low-density, microcellular foams have been prepared from the hydrocarbon polymer poly(4-methyl-l-pentene) via a similar phase inversion process using homogenous solutions in organic solvents. These foams have densities from 2 to 5 mg/cm 3 and average cell sizes of 20 micrometers. The physical-chemical aspects of the thermally induced phase inversion process is presented

  2. Analyses of the pathways involved in early- and late-phase induction of IFN-beta during C. muridarum infection of oviduct epithelial cells.

    Directory of Open Access Journals (Sweden)

    Sishun Hu

    Full Text Available We previously reported that the IFN-β secreted by Chlamydia muridarum-infected murine oviduct epithelial cells (OE cells was mostly dependent on the TLR3 signaling pathway. To further characterize the mechanisms of IFN-β synthesis during Chlamydia infection of OE cells in vitro, we utilized specific inhibitory drugs to clarify the roles of IRF3 and NF-κB on both early- and late-phase C. muridarum infections. Our results showed that the pathways involved in the early-phase of IFN-β production were distinct from that in the late-phase of IFN-β production. Disruption of IRF3 activation using an inhibitor of TBK-1 at early-phase Chlamydia infection had a significant impact on the overall synthesis of IFN-β; however, disruption of IRF3 activation at late times during infection had no effect. Interestingly, inhibition of NF-κB early during Chlamydia infection also had a negative effect on IFN-β production; however, its impact was not significant. Our data show that the transcription factor IRF7 was induced late during Chlamydia infection, which is indicative of a positive feedback mechanism of IFN-β synthesis late during infection. In contrast, IRF7 appears to play little or no role in the early synthesis of IFN-β during Chlamydia infection. Finally, we demonstrate that antibiotics that target chlamydial DNA replication are much more effective at reducing IFN-β synthesis during infection versus antibiotics that target chlamydial transcription. These results provide evidence that early- and late-phase IFN-β production have distinct signaling pathways in Chlamydia-infected OE cells, and suggest that Chlamydia DNA replication might provide a link to the currently unknown chlamydial PAMP for TLR3.

  3. Chemical Pollutants Released to the Marine Environment by Degradation of Plastic Debris

    OpenAIRE

    Gewert, Berit

    2018-01-01

    Since the beginning of the mass production in the 1940s, plastic has been manufactured in quickly increasing amounts. Plastic debris accumulates in the environment and lately much attention has been drawn to the pollution in the world’s oceans. Despite the rapid development and ubiquitous presence of plastic, degradation in the marine environment and potential risks associated with plastic are not fully understood. Thus, these knowledge gaps were addressed in this thesis, which adds informati...

  4. Effect of embedment on the plastic behaviour of Bucket Foundations

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Barari, Amin; Larsen, Kim André

    2015-01-01

    studies have indicated the possibility of defining foundation response using plasticity theory. Results of multiple loading tests addressing the effect of embedment on the strain-hardening behavior of shallow bucket foundations under combined loading are reported. The kinematic mechanisms accompanying pre......-failure are presented. It is argued that the drained capacity of offshore bucket foundations and the ratio of plastic increments are largely influenced by embedment depth and the preload ratio V/Vpeak....

  5. Changes in the composition of ichthyoplankton assemblage and plastic debris in mangrove creeks relative to moon phases.

    Science.gov (United States)

    Lima, A R A; Barletta, M; Costa, M F; Ramos, J A A; Dantas, D V; Melo, P A M C; Justino, A K S; Ferreira, G V B

    2016-07-01

    Lunar influence on the distribution of fish larvae, zooplankton and plastic debris in mangrove creeks of the Goiana Estuary, Brazil, was studied over a lunar cycle. Cetengraulis edentulus, Anchovia clupeoides and Rhinosardinia bahiensis were the most abundant fish larvae (56·6%), independent of the moon phase. The full moon had a positive influence on the abundance of Gobionellus oceanicus, Cynoscion acoupa and Atherinella brasiliensis, and the new moon on Ulaema lefroyi. The full and new moons also influenced the number of zoeae and megalopae of Ucides cordatus, protozoeae and larvae of caridean shrimps, and the number of hard and soft plastic debris, both 5 mm. Micro and macroplastics were present in samples from all 12 creeks studied, at densities similar to the third most abundant taxon, R. bahiensis. Cetengraulis edentulus and R. bahiensis showed a strong positive correlation with the last quarter moon, when there was less zooplankton available in the creeks and higher abundance of microplastic threads. Anchovia clupeoides, Diapterus rhombeus, U. lefroyi and hard microplastics were positively associated with different moon phases, when calanoid copepods, Caridean larvae and zoeae of U. cordatus were highly available in the creeks. Cynoscion acoupa, G. oceanicus and A. brasiliensis were strongly associated with the full moon, when protozoeae of caridean shrimps and megalopae of U. cordatus were also highly available, as were hard and soft macroplastics, paint chips (mangrove creeks as nursery habitats. The moon phases influenced the distribution of fish larvae species, zooplankton and plastic debris by changing their compositions and abundances in the mangrove creeks of the Goiana Estuary when under the influence of different tidal current regimes. © 2015 The Fisheries Society of the British Isles.

  6. Identification and initial assessment of candidate BWR late-phase in-vessel accident management strategies

    International Nuclear Information System (INIS)

    Hodge, S.A.

    1991-01-01

    Work sponsored by the United States Nuclear Regulatory Commission (USNRC) to identify and perform preliminary assessments of candidate BWR [boiling water reactor] in-vessel accident management strategies was completed at Oak Ridge National Laboratory (ORNL) during fiscal year 1990. Mitigative strategies for containment events have been the subject of a companion study at Brookhaven National Laboratory. The focus of this Oak Ridge effort was the development of new strategies for mitigation of the late phase events, that is, the events that would occur in-vessel after the onset of significant core damage. The work began with an investigation of the current status of BWR in-vessel accident management procedures and proceeded through a preliminary evaluation of several candidate new strategies. The steps leading to the identification of the candidate strategies are described. The four new candidate late-phase (in-vessel) accident mitigation strategies identified by this study and discussed in the report are: (1) keep the reactor vessel depressurized; (2) restore injection in a controlled manner; (3) inject boron if control blade damage has occurred; and (4) containment flooding to maintain core and structural debris in-vessel. Additional assessments of these strategies are proposed

  7. Plastic debris retention and exportation by a mangrove forest patch.

    Science.gov (United States)

    Ivar do Sul, Juliana A; Costa, Monica F; Silva-Cavalcanti, Jacqueline S; Araújo, Maria Christina B

    2014-01-15

    An experiment observed the behavior of selected tagged plastic items deliberately released in different habitats of a tropical mangrove forest in NE Brazil in late rainy (September) and late dry (March) seasons. Significant differences were not reported among seasons. However, marine debris retention varied among habitats, according to characteristics such as hydrodynamic (i.e., flow rates and volume transported) and relative vegetation (Rhizophora mangle) height and density. The highest grounds retained significantly more items when compared to the borders of the river and the tidal creek. Among the used tagged items, PET bottles were more observed and margarine tubs were less observed, being easily transported to adjacent habitats. Plastic bags were the items most retained near the releasing site. The balance between items retained and items lost was positive, demonstrating that mangrove forests tend to retain plastic marine debris for long periods (months-years). Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Long-Term Improvements After Multimodal Rehabilitation in Late Phase After Stroke: A Randomized Controlled Trial.

    Science.gov (United States)

    Bunketorp-Käll, Lina; Lundgren-Nilsson, Åsa; Samuelsson, Hans; Pekny, Tulen; Blomvé, Karin; Pekna, Marcela; Pekny, Milos; Blomstrand, Christian; Nilsson, Michael

    2017-07-01

    Treatments that improve function in late phase after stroke are urgently needed. We assessed whether multimodal interventions based on rhythm-and-music therapy or horse-riding therapy could lead to increased perceived recovery and functional improvement in a mixed population of individuals in late phase after stroke. Participants were assigned to rhythm-and-music therapy, horse-riding therapy, or control using concealed randomization, stratified with respect to sex and stroke laterality. Therapy was given twice a week for 12 weeks. The primary outcome was change in participants' perception of stroke recovery as assessed by the Stroke Impact Scale with an intention-to-treat analysis. Secondary objective outcome measures were changes in balance, gait, grip strength, and cognition. Blinded assessments were performed at baseline, postintervention, and at 3- and 6-month follow-up. One hundred twenty-three participants were assigned to rhythm-and-music therapy (n=41), horse-riding therapy (n=41), or control (n=41). Post-intervention, the perception of stroke recovery (mean change from baseline on a scale ranging from 1 to 100) was higher among rhythm-and-music therapy (5.2 [95% confidence interval, 0.79-9.61]) and horse-riding therapy participants (9.8 [95% confidence interval, 6.00-13.66]), compared with controls (-0.5 [-3.20 to 2.28]); P =0.001 (1-way ANOVA). The improvements were sustained in both intervention groups 6 months later, and corresponding gains were observed for the secondary outcomes. Multimodal interventions can improve long-term perception of recovery, as well as balance, gait, grip strength, and working memory in a mixed population of individuals in late phase after stroke. URL: http//www.ClinicalTrials.gov. Unique identifier: NCT01372059. © 2017 American Heart Association, Inc.

  9. Micromechanical analysis of martensite distribution on strain localization in dual phase steels by scanning electron microscopy and crystal plasticity simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, M. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Ziaei-Rad, S., E-mail: szrad@cc.iut.ac.ir [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Saeidi, N. [Department of Materials Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Jamshidian, M. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2016-07-18

    The morphology and distribution of the dispersed martensite islands in the ferrite matrix plays a key role in the formation of shear bands in dual phase steels. In this study, we investigate the relationship between the martensite dispersion and the strain localization regions due to the formation of shear bands in fine-grained DP 780 steel, employing experimental observations as well as numerical simulations. SEM studies of the deformed microstructure showed that voids nucleated at ferrite-martensite interface within larger ferrite grains and regions with low local martensite fraction. The experimental results were precisely analyzed by finite element simulations based on the theory of crystal plasticity. A parametric study was then performed to obtain a deeper insight in to the effect of martensite dispersion on the strain localization of the neighboring ferrite. Crystal plasticity simulation results revealed that in a more regular structure compared to a random structure, a greater region of the ferrite phase contributes to accommodate plasticity. In addition, these regions limit the formation of main shear bands by creating barriers against stress concentration regions, results in lower growth and interaction of stress concentration regions with each others.

  10. Will phenotypic plasticity affecting flowering phenology keep pace with climate change?

    Science.gov (United States)

    Richardson, Bryce A; Chaney, Lindsay; Shaw, Nancy L; Still, Shannon M

    2017-06-01

    Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity can accommodate projected temperature change for this century. Evaluating clines in phenological traits and the extent and variation in plasticity can provide key information on assessing risk of maladaptation and developing strategies to mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemisia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to late November among gardens. Mixed-effects modeling explained 79% of variation in flowering date, of which 46% could be assigned to plasticity and genetic variation in plasticity and 33% to genetics (conditional R 2  = 0.79, marginal R 2  = 0.33). Two environmental variables that explained the genetic variation were photoperiod and the onset of spring, the Julian date of accumulating degree-days >5 °C reaching 100. The genetic variation was mapped for contemporary and future climates (decades 2060 and 2090), showing flower date change varies considerably across the landscape. Plasticity was estimated to accommodate, on average, a ±13-day change in flowering date. However, the examination of genetic variation in plasticity suggests that the magnitude of plasticity could be affected by variation in the sensitivity to photoperiod and temperature. In a warmer common garden, lower-latitude populations have greater plasticity (+16 days) compared to higher-latitude populations (+10 days). Mapped climatypes of flowering date for contemporary and future climates illustrate the wide breadth of plasticity and large geographic overlap. Our research highlights the importance of integrating information on genetic variation, phenotypic plasticity and climatic niche modeling to evaluate plant responses and elucidate vulnerabilities to climate change. Published 2016. This article is a U.S. Government work and is in the

  11. Raman study of the molecular motions of pivalic acid: the liquid—plastic phase transition

    Science.gov (United States)

    Balevičius, V.; Orel, B.; Hadži, D.

    Raman spectra of pivalic acid in the plastic and liquid phase have been measured. The reorientational correlation times have been evaluated from the ν asCH, νCO and νCC bands as a function of temperature. The reorientational correlation time corresponding to ν as CH and νCC bands is τ 4ps ( T = 20°C). The calculated activation energy is 26 KJ mol -1. The reorientation of the carboxylic groups which may be assisted by the proton transfer along the hydrogen bonds in dimers is discussed.

  12. Differential association with cellular substructures of pseudorabies virus DNA during early and late phases of replication

    International Nuclear Information System (INIS)

    Ben-Porat, T.; Veach, R.A.; Blankenship, M.L.; Kaplan, A.S.

    1984-01-01

    Pseudorabies virus DNA synthesis can be divided into two phases, early and late, which can be distinguished from each other on the basis of the structures of the replicating DNA. The two types of replicating virus DNA can also be distinguished from each other on the basis of the cellular substructures with which each is associated. Analysis by electron microscopic autoradiography showed that during the first round of replication, nascent virus DNA was found in the vicinity of the nuclear membrane; during later rounds of replication the nascent virus DNA was located centrally within the nucleus. The degree of association of virus DNA synthesized at early and late phases with the nuclear matrix fractions also differed; a larger proportion of late than of early nascent virus DNA was associated with this fraction. While nascent cellular DNA only was associated in significant amounts with the nuclear matrix fraction, a large part (up to 40%) of all the virus DNA remained associated with this fraction. However, no retention of specific virus proteins in this fraction was observed. Except for two virus proteins, which were preferentially extracted from the nuclear matrix, approximately 20% of all virus proteins remained in the nuclear matrix fraction. The large proportion of virus DNA associated with the nuclear fraction indicated that virus DNA may be intimately associated with some proteins

  13. Dynamic elastic-plastic behaviour of a frame including coupled bending and torsion

    International Nuclear Information System (INIS)

    Messmer, S.; Sayir, M.

    1989-01-01

    The full time response of a space frame under impact loading perpendicular to the frame plane is discussed. Theoretical solutions and experimental results are presented and compared. A space frame clamped at its two ends is loaded by a 0.22 lead bullet that hits a mass in the middle of the transversal beam of the frame. The loading time is about 40 to 60 μs and the resulting linear momentum of the impact in the experiment is 0.5 to 1 N s. The time response of this frame can be divided in four phases where different physical effects are dominant: (a) The loading phase where elastic wave motion dominates the time response. Because of the high impact forces, plastic deformation occurs in the vicinity of the mass and must be included in a theoretical model. The influence of reflections at the corners on the time response is shown in theory and experiment. (b) The evolution phase. Within this phase, a plastic collapse mechanism develops. Most of this phase is dominated by elastic deformation but local plastic deformations beside the mass are also present. Because many reflections at corners, clamps and the mass occur within this phase, a modal analysis method is used to predict time histories. (c) The plastic phase with plastic zones at the clamps. The phase sets in after the bending wave reaches the clamps. It is characterized by plastic deformation near the clamps and elastic deformation of the other parts of the frame. We used a modal analysis including plastic 'modes' to get accurate results. (d) The elastic vibration phase

  14. Evolution of the structure and the phase composition of a bainitic structural steel during plastic deformation

    Science.gov (United States)

    Nikitina, E. N.; Glezer, A. M.; Ivanov, Yu. F.; Aksenova, K. V.; Gromov, V. E.; Kazimirov, S. A.

    2017-10-01

    The evolution of the phase composition and the imperfect substructure of the 30Kh2N2MFA bainitic structural steel subjected to compressive deformation by 36% is quantitatively analyzed. It is shown that deformation is accompanied by an increase in the scalar dislocation density, a decrease in the longitudinal fragment sizes, an increase in the number of stress concentrators, the dissolution of cementite particles, and the transformation of retained austenite.

  15. Late-phase MSCT in the different stages of myocardial infarction: animal experiments

    International Nuclear Information System (INIS)

    Mahnken, Andreas H.; Bruners, Philipp; Kinzel, Sylvia; Katoh, Marcus; Muehlenbruch, Georg; Guenther, Rolf W.; Wildberger, Joachim E.

    2007-01-01

    The purpose of this study was to intraindividually evaluate myocardial late enhancement on multislice spiral computed tomography (MSCT) for the assessment of the different stages of myocardial infarction (MI) in comparison with magnetic resonance (MR) imaging. Reperfused MI was successfully induced in seven pigs. Delayed enhancement MR imaging and late-phase MSCT were performed on day 0 as well as 7, 28 and 90 days after the procedure. The pigs were sacrificed, and 2,3,5-triphenyltetrazolin-chloride (TTC) staining was acquired. MI size was compared between the different imaging techniques and over time applying Bland-Altman plots and multivariate analysis with repeated measures. On day 0 the mean MI size was 23.7 ± 11.8% of the left ventricular area on MSCT and 24.5 ± 10.6% on MR imaging. On day 90 infarct sizes decreased significantly to 16.9 ± 8.4% and 18.9 ± 8.0%, respectively (P 0.0019). On TTC staining the size of MI was 16.8 ± 8.2%. Bland-Altman plots showed a good agreement between MSCT and MR imaging with mean deviations ranging from -3.4% to -1.9%. No significant difference between MSCT and MR imaging was found. Myocardial late enhancement on MSCT correlates well with delayed enhancement MR imaging during the different stages of MI and allows for reliable assessment of reperfused MI during acute, subacute and chronic stages. (orig.)

  16. Status Update on the NCRP Scientific Committee SC 5-1 Report: Decision Making for Late-Phase Recovery from Nuclear or Radiological Incidents - 13450

    International Nuclear Information System (INIS)

    Chen, S.Y.

    2013-01-01

    In August 2008, the U.S. Department of Homeland Security (DHS) issued its final Protective Action Guide (PAG) for radiological dispersal device (RDD) and improvised nuclear device (IND) incidents. This document specifies protective actions for public health during the early and intermediate phases and cleanup guidance for the late phase of RDD or IND incidents, and it discusses approaches to implementing the necessary actions. However, while the PAG provides specific guidance for the early and intermediate phases, it prescribes no equivalent guidance for the late-phase cleanup actions. Instead, the PAG offers a general description of a complex process using a site-specific optimization approach. This approach does not predetermine cleanup levels but approaches the problem from the factors that would bear on the final agreed-on cleanup levels. Based on this approach, the decision-making process involves multifaceted considerations including public health, the environment, and the economy, as well as socio-political factors. In an effort to fully define the process and approach to be used in optimizing late-phase recovery and site restoration following an RDD or IND incident, DHS has tasked the NCRP with preparing a comprehensive report addressing all aspects of the optimization process. Preparation of the NCRP report is a three-year (2010-2013) project assigned to a scientific committee, the Scientific Committee (SC) 5-1; the report was initially titled, Approach to Optimizing Decision Making for Late- Phase Recovery from Nuclear or Radiological Terrorism Incidents. Members of SC 5-1 represent a broad range of expertise, including homeland security, health physics, risk and decision analysis, economics, environmental remediation and radioactive waste management, and communication. In the wake of the Fukushima nuclear accident of 2011, and guided by a recent process led by the White House through a Principal Level Exercise (PLE), the optimization approach has since

  17. Status Update on the NCRP Scientific Committee SC 5-1 Report: Decision Making for Late-Phase Recovery from Nuclear or Radiological Incidents - 13450

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S.Y. [Environmental Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2013-07-01

    In August 2008, the U.S. Department of Homeland Security (DHS) issued its final Protective Action Guide (PAG) for radiological dispersal device (RDD) and improvised nuclear device (IND) incidents. This document specifies protective actions for public health during the early and intermediate phases and cleanup guidance for the late phase of RDD or IND incidents, and it discusses approaches to implementing the necessary actions. However, while the PAG provides specific guidance for the early and intermediate phases, it prescribes no equivalent guidance for the late-phase cleanup actions. Instead, the PAG offers a general description of a complex process using a site-specific optimization approach. This approach does not predetermine cleanup levels but approaches the problem from the factors that would bear on the final agreed-on cleanup levels. Based on this approach, the decision-making process involves multifaceted considerations including public health, the environment, and the economy, as well as socio-political factors. In an effort to fully define the process and approach to be used in optimizing late-phase recovery and site restoration following an RDD or IND incident, DHS has tasked the NCRP with preparing a comprehensive report addressing all aspects of the optimization process. Preparation of the NCRP report is a three-year (2010-2013) project assigned to a scientific committee, the Scientific Committee (SC) 5-1; the report was initially titled, Approach to Optimizing Decision Making for Late- Phase Recovery from Nuclear or Radiological Terrorism Incidents. Members of SC 5-1 represent a broad range of expertise, including homeland security, health physics, risk and decision analysis, economics, environmental remediation and radioactive waste management, and communication. In the wake of the Fukushima nuclear accident of 2011, and guided by a recent process led by the White House through a Principal Level Exercise (PLE), the optimization approach has since

  18. Traumatic Brain Injury Pathophysiology and Treatments: Early, Intermediate, and Late Phases Post-Injury

    Science.gov (United States)

    Algattas, Hanna; Huang, Jason H.

    2014-01-01

    Traumatic Brain Injury (TBI) affects a large proportion and extensive array of individuals in the population. While precise pathological mechanisms are lacking, the growing base of knowledge concerning TBI has put increased emphasis on its understanding and treatment. Most treatments of TBI are aimed at ameliorating secondary insults arising from the injury; these insults can be characterized with respect to time post-injury, including early, intermediate, and late pathological changes. Early pathological responses are due to energy depletion and cell death secondary to excitotoxicity, the intermediate phase is characterized by neuroinflammation and the late stage by increased susceptibility to seizures and epilepsy. Current treatments of TBI have been tailored to these distinct pathological stages with some overlap. Many prophylactic, pharmacologic, and surgical treatments are used post-TBI to halt the progression of these pathologic reactions. In the present review, we discuss the mechanisms of the pathological hallmarks of TBI and both current and novel treatments which target the respective pathways. PMID:24381049

  19. Preparation of macroporous zirconia monoliths from ionic precursors via an epoxide-mediated sol-gel process accompanied by phase separation

    International Nuclear Information System (INIS)

    Guo, Xingzhong; Song, Jie; Lvlin, Yixiu; Yang, Hui; Nakanishi, Kazuki; Kanamori, Kazuyoshi

    2015-01-01

    Monolithic macroporous zirconia (ZrO 2 ) derived from ionic precursors has been successfully fabricated via the epoxide-mediated sol-gel route accompanied by phase separation in the presence of propylene oxide (PO) and poly(ethylene oxide) (PEO). The addition of PO used as an acid scavenger mediates the gelation, whereas PEO enhances the polymerization-induced phase separation. The appropriate choice of the starting compositions allows the production of a macroporous zirconia monolith with a porosity of 52.9% and a Brunauer–Emmett–Teller (BET) surface area of 171.9 m 2 · g −1 . The resultant dried gel is amorphous, whereas tetragonal ZrO 2 and monoclinic ZrO 2 are precipitated at 400 and 600 °C, respectively, without spoiling the macroporous morphology. After solvothermal treatment with an ethanol solution of ammonia, tetragonal ZrO 2 monoliths with smooth skeletons and well-defined mesopores can be obtained, and the BET surface area is enhanced to 583.8 m 2 · g −1 . (paper)

  20. Cortical and brainstem plasticity in Tourette syndrome and obsessive-compulsive disorder.

    Science.gov (United States)

    Suppa, Antonio; Marsili, Luca; Di Stasio, Flavio; Berardelli, Isabella; Roselli, Valentina; Pasquini, Massimo; Cardona, Francesco; Berardelli, Alfredo

    2014-10-01

    Gilles de la Tourette syndrome is characterized by motor/vocal tics commonly associated with psychiatric disorders, including obsessive-compulsive disorder. We investigated primary motor cortex and brainstem plasticity in Tourette patients, exposed and unexposed to chronic drug treatment, with and without psychiatric disturbances. We also investigated primary motor cortex and brainstem plasticity in obsessive-compulsive disorder. We studied 20 Tourette patients with and without psychiatric disturbances, 15 with obsessive-compulsive disorder, and 20 healthy subjects. All groups included drug-naïve patients. We conditioned the left primary motor cortex with intermittent/continuous theta-burst stimulation and recorded motor evoked potentials. We conditioned the supraorbital nerve with facilitatory/inhibitory high-frequency stimulation and recorded the blink reflex late response area. In healthy subjects, intermittent theta-burst increased and continuous theta-burst stimulation decreased motor evoked potentials. Differently, intermittent theta-burst failed to increase and continuous theta-burst stimulation failed to decrease motor evoked potentials in Tourette patients, with and without psychiatric disturbances. In obsessive-compulsive disorder, intermittent/continuous theta-burst stimulation elicited normal responses. In healthy subjects and in subjects with obsessive-compulsive disorder, the blink reflex late response area increased after facilitatory high-frequency and decreased after inhibitory high-frequency stimulation. Conversely, in Tourette patients, with and without psychiatric disturbances, facilitatory/inhibitory high-frequency stimulation left the blink reflex late response area unchanged. Theta-burst and high-frequency stimulation elicited similar responses in drug-naïve and chronically treated patients. Tourette patients have reduced plasticity regardless of psychiatric disturbances. These findings suggest that abnormal plasticity contributes to the

  1. Sirtinol abrogates late phase of cardiac ischemia preconditioning in rats.

    Science.gov (United States)

    Safari, Fereshteh; Shekarforoosh, Shahnaz; Hashemi, Tahmineh; Namvar Aghdash, Simin; Fekri, Asefeh; Safari, Fatemeh

    2017-07-01

    The aim of this study was to investigate the effect of sirtinol, as an inhibitor of sirtuin NAD-dependent histone deacetylases, on myocardial ischemia reperfusion injury following early and late ischemia preconditioning (IPC). Rats underwent sustained ischemia and reperfusion (IR) alone or proceeded by early or late IPC. Sirtinol (S) was administered before IPC. Arrhythmias were evaluated based on the Lambeth model. Infarct size (IS) was measured using triphenyltetrazolium chloride staining. The transcription level of antioxidant-coding genes was assessed by real-time PCR. In early and late IPC groups, IS and the number of arrhythmia were significantly decreased (P < 0.05 and P < 0.01 vs IR, respectively). In S + early IPC, incidences of arrhythmia and IS were not different compared with the early IPC group. However, in S + late IPC the IS was different from the late IPC group (P < 0.05). In late IPC but not early IPC, transcription levels of catalase (P < 0.01) and Mn-SOD (P < 0.05) increased, although this upregulation was not significant in the S + late IPC group. Our results are consistent with the notion that different mechanisms are responsible for early and late IPC. In addition, sirtuin NAD-dependent histone deacetylases may be implicated in late IPC-induced cardioprotection.

  2. The role of connective tissue in late effects of radiation

    International Nuclear Information System (INIS)

    Gerber, G.B.

    1979-01-01

    Connective tissues not only serve as support, but also filter and censor the physical and molecular information reaching cells. The late change in connective tissues, i.e. fibrosis several months or years after the irradiation with 1000 rad or more, has been well known, and the dreaded sequel of radiation therapy, but connective tissues are affected already at much earlier time. The change in irradiated connective tissues may be distinguished in 3 phases after irradiation, the change in permeability within hours, damage to cell replacement systems within days and months and the late change of fibrosis, vascular damage and parenchymal atrophy after months and years. Glomerular sclerosis, tubular atrophy and interstitial fibrosis after the excessive irradiation of kidneys, accompanied by renal failure and hypertension, are usually considered as the consequence of vascular or tubular damage, but recent investigation suggested that the change in blood flow is correlated also with the increase in collagen, so that fibrosis may represent an important factor in the pathogenesis of renal damage. Radiofibrosis is considered simply as a result of the vascular damage due to the deficient or abnormal replacement of endothelial cells and/or due to arteriolo-capillary fibrosis. The late effects depend on early ones, and the endothelial cells would be only one. Other possible paths could depend on low fibrinolytic activity and immunological reactions. (Yamashita, S.)

  3. Learning-Dependent Plasticity of the Barrel Cortex Is Impaired by Restricting GABA-Ergic Transmission.

    Science.gov (United States)

    Posluszny, Anna; Liguz-Lecznar, Monika; Turzynska, Danuta; Zakrzewska, Renata; Bielecki, Maksymilian; Kossut, Malgorzata

    2015-01-01

    Experience-induced plastic changes in the cerebral cortex are accompanied by alterations in excitatory and inhibitory transmission. Increased excitatory drive, necessary for plasticity, precedes the occurrence of plastic change, while decreased inhibitory signaling often facilitates plasticity. However, an increase of inhibitory interactions was noted in some instances of experience-dependent changes. We previously reported an increase in the number of inhibitory markers in the barrel cortex of mice after fear conditioning engaging vibrissae, observed concurrently with enlargement of the cortical representational area of the row of vibrissae receiving conditioned stimulus (CS). We also observed that an increase of GABA level accompanied the conditioning. Here, to find whether unaltered GABAergic signaling is necessary for learning-dependent rewiring in the murine barrel cortex, we locally decreased GABA production in the barrel cortex or reduced transmission through GABAA receptors (GABAARs) at the time of the conditioning. Injections of 3-mercaptopropionic acid (3-MPA), an inhibitor of glutamic acid decarboxylase (GAD), into the barrel cortex prevented learning-induced enlargement of the conditioned vibrissae representation. A similar effect was observed after injection of gabazine, an antagonist of GABAARs. At the behavioral level, consistent conditioned response (cessation of head movements in response to CS) was impaired. These results show that appropriate functioning of the GABAergic system is required for both manifestation of functional cortical representation plasticity and for the development of a conditioned response.

  4. Secretory activity and cell cycle alteration of alveolar type II cells in the early and late phase after irradiation

    International Nuclear Information System (INIS)

    Willner, Jochen; Vordermark, Dirk; Schmidt, Michael; Gassel, Andreamaria; Flentje, Michael; Wirtz, Hubert

    2003-01-01

    Purpose: Type II cells and the surfactant system have been proposed to play a central role in pathogenesis of radiation pneumonitis. We analyzed the secretory function and proliferation parameters of alveolar type II cells in the early (until 24 h) and late phase (1-5 weeks) after irradiation (RT) in vitro and in vivo. Methods and Materials: Type II cells were isolated from rats according to the method of Dobbs. Stimulation of secretion was induced with terbutaline, adenosine triphosphate (ATP), and 12-O-tetradecanoylphorbol-13-acetate (TPA) for a 2-h period. Determination of secretion was performed using 3 H-labeled phosphatidylcholine. For the early-phase analysis, freshly isolated and adherent type II cells were irradiated in vitro with 9-21 Gy (stepwise increase of 3 Gy). Secretion stimulation was initiated 1, 6, 24, and 48 h after RT. For late-phase analysis, type II cells were isolated 1-5 weeks after 18 Gy whole lung or sham RT. Each experiment was repeated at least fivefold. Flow cytometry was used to determine cell cycle distribution and proliferating cell nuclear antigen index. Results: During the early-phase (in vitro) analysis, we found a normal stimulation of surfactant secretion in irradiated, as well as unirradiated, cells. No change in basal secretion and no dose effect were seen. During the late phase, 1-5 weeks after whole lung RT, we observed enhanced secretory activity for all secretagogues and a small increase in basal secretion in Weeks 3 and 4 (pneumonitis phase) compared with controls. The total number of isolated type II cells, as well as the rate of viable cells, decreased after the second post-RT week. Cell cycle alterations suggesting an irreversible G 2 /M block occurred in the second post-RT week and did not resolve during the observation period. The proliferating cell nuclear antigen index of type II cells from irradiated rats did not differ from that of controls. Conclusion: In contrast to literature data, we observed no direct

  5. Precipitation of the sigma-phase in Mo-Re alloys

    International Nuclear Information System (INIS)

    Freze, N.I.; Levitskij, A.D.; Tyumentsev, A.N.; Korotaev, A.D.

    1975-01-01

    Disintegration processes in thin foils and replicas of alloys Mo+(52 - 56) wpc Re and Mo+(52 - 56)% Re+(0.05 - 0.10)% Fe wpc were studied by electronic microscopy. Alloying with iron was conducted to determine the effect of iron atom segregations at the grain boundaries on separation of the sigma-phase in these regions. Since the nature of disintegration in all alloys was identical, the experimental data were considered on the example of alloy Mo + 54 wpc Re. The laminated specimens of 1 - 2 mm in thickness subjected to cold rolling with subsequent tempering at T = 1100 deg C for 15 min were characterized by intensive disintegration. As a result finelydispersed laminated sigma-phase uniformly distributed throughout the entire volume of the material was formed. The non-deformed specimens did not show separation of the sigma-phase. As a result of separation of the finely-dispersed sigma-phase plasticity of the alloys was increased. So that a foil of Δh = 0.2 mm in thickness can be produced by cold rolling of the laminated specimens without intermediate annealing. By changing the initial state of the specimens and temperature of annealing dispersity and spatial distribution of the sigma-phase may be substantially modified. It provides for considerably increasing plasticity of the two-phase alloys. During separation of the sigma-phase hardness of the deformed specimens becomes greater. Therefore the low-temperature disintegration accompanied by separation of the sigma-phase may be employed for disperse strengthening of the Mo-Re alloys. The refractory properties of such alloye will not be high, since it is coagulated the finely-dispersed segregations of the sigma-phase even at T > 1100 deg C

  6. Ischemic long-term-potentiation (iLTP: perspectives to set the threshold of neural plasticity toward therapy

    Directory of Open Access Journals (Sweden)

    Maximilian Lenz

    2015-01-01

    Full Text Available The precise role of neural plasticity under pathological conditions remains not well understood. It appears to be well accepted, however, that changes in the ability of neurons to express plasticity accompany neurological diseases. Here, we discuss recent experimental evidence, which suggests that synaptic plasticity induced by a pathological stimulus, i.e., ischemic long-term-potentiation (iLTP of excitatory synapses, could play an important role for post-stroke recovery by influencing the post-lesional reorganization of surviving neuronal networks.

  7. Accompanied consultations in occupational health.

    Science.gov (United States)

    Hobson, J; Hobson, H; Sharp, R

    2016-04-01

    Accompanied consultations are often reported as difficult by occupational physicians but have not been studied in the occupational health setting. To collect information about accompanied consultations and the impact of the companion on the consultation. We collected data on all accompanied consultations by two occupational physicians working in a private sector occupational health service over the course of 16 months. Accompanied consultations were matched to non-accompanied consultations for comparison. We collected data on 108 accompanied consultations. Accompanied consultations were more likely to be connected with ill health retirement (P Occupational health practitioners may benefit from better understanding of accompanied consultations and guidance on their management. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. A High-Rate, Single-Crystal Model including Phase Transformations, Plastic Slip, and Twinning

    Energy Technology Data Exchange (ETDEWEB)

    Addessio, Francis L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bronkhorst, Curt Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bolme, Cynthia Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Explosive Science and Shock Physics Division; Brown, Donald William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lebensohn, Ricardo A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lookman, Turab [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Luscher, Darby Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Mayeur, Jason Rhea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Morrow, Benjamin M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Rigg, Paulo A. [Washington State Univ., Pullman, WA (United States). Dept. of Physics. Inst. for Shock Physics

    2016-08-09

    An anisotropic, rate-­dependent, single-­crystal approach for modeling materials under the conditions of high strain rates and pressures is provided. The model includes the effects of large deformations, nonlinear elasticity, phase transformations, and plastic slip and twinning. It is envisioned that the model may be used to examine these coupled effects on the local deformation of materials that are subjected to ballistic impact or explosive loading. The model is formulated using a multiplicative decomposition of the deformation gradient. A plate impact experiment on a multi-­crystal sample of titanium was conducted. The particle velocities at the back surface of three crystal orientations relative to the direction of impact were measured. Molecular dynamics simulations were conducted to investigate the details of the high-­rate deformation and pursue issues related to the phase transformation for titanium. Simulations using the single crystal model were conducted and compared to the high-­rate experimental data for the impact loaded single crystals. The model was found to capture the features of the experiments.

  9. Spatio-temporal re-organization of replication foci accompanies replication domain consolidation during human pluripotent stem cell lineage specification

    Science.gov (United States)

    Wilson, Korey A.; Elefanty, Andrew G.; Stanley, Edouard G.; Gilbert, David M.

    2016-01-01

    ABSTRACT Lineage specification of both mouse and human pluripotent stem cells (PSCs) is accompanied by spatial consolidation of chromosome domains and temporal consolidation of their replication timing. Replication timing and chromatin organization are both established during G1 phase at the timing decision point (TDP). Here, we have developed live cell imaging tools to track spatio-temporal replication domain consolidation during differentiation. First, we demonstrate that the fluorescence ubiquitination cell cycle indicator (Fucci) system is incapable of demarcating G1/S or G2/M cell cycle transitions. Instead, we employ a combination of fluorescent PCNA to monitor S phase progression, cytokinesis to demarcate mitosis, and fluorescent nucleotides to label early and late replication foci and track their 3D organization into sub-nuclear chromatin compartments throughout all cell cycle transitions. We find that, as human PSCs differentiate, the length of S phase devoted to replication of spatially clustered replication foci increases, coincident with global compartmentalization of domains into temporally clustered blocks of chromatin. Importantly, re-localization and anchorage of domains was completed prior to the onset of S phase, even in the context of an abbreviated PSC G1 phase. This approach can also be employed to investigate cell fate transitions in single PSCs, which could be seen to differentiate preferentially from G1 phase. Together, our results establish real-time, live-cell imaging methods for tracking cell cycle transitions during human PSC differentiation that can be applied to study chromosome domain consolidation and other aspects of lineage specification. PMID:27433885

  10. Levetiracetam attenuates hippocampal expression of synaptic plasticity-related immediate early and late response genes in amygdala-kindled rats

    Directory of Open Access Journals (Sweden)

    Watson William P

    2010-01-01

    Full Text Available Abstract Background The amygdala-kindled rat is a model for human temporal lobe epilepsy and activity-dependent synaptic plasticity. Hippocampal RNA isolated from amygdala-kindled rats at different kindling stages was analyzed to identify kindling-induced genes. Furthermore, effects of the anti-epileptic drug levetiracetam on kindling-induced gene expression were examined. Results Cyclooxygenase-2 (Cox-2, Protocadherin-8 (Pcdh8 and TGF-beta-inducible early response gene-1 (TIEG1 were identified and verified as differentially expressed transcripts in the hippocampus of kindled rats by in situ hybridization and quantitative RT-PCR. In addition, we identified a panel of 16 additional transcripts which included Arc, Egr3/Pilot, Homer1a, Ania-3, MMP9, Narp, c-fos, NGF, BDNF, NT-3, Synaptopodin, Pim1 kinase, TNF-α, RGS2, Egr2/krox-20 and β-A activin that were differentially expressed in the hippocampus of amygdala-kindled rats. The list consists of many synaptic plasticity-related immediate early genes (IEGs as well as some late response genes encoding transcription factors, neurotrophic factors and proteins that are known to regulate synaptic remodelling. In the hippocampus, induction of IEG expression was dependent on the afterdischarge (AD duration. Levetiracetam, 40 mg/kg, suppressed the development of kindling measured as severity of seizures and AD duration. In addition, single animal profiling also showed that levetiracetam attenuated the observed kindling-induced IEG expression; an effect that paralleled the anti-epileptic effect of the drug on AD duration. Conclusions The present study provides mRNA expression data that suggest that levetiracetam attenuates expression of genes known to regulate synaptic remodelling. In the kindled rat, levetiracetam does so by shortening the AD duration thereby reducing the seizure-induced changes in mRNA expression in the hippocampus.

  11. Late division kinetics in relation to modification of protein synthesis in mouse eggs blocked in the G2 phase after X-irradiation; and comment

    International Nuclear Information System (INIS)

    Grinfeld, S.; Gilles, J.; Jacquet, P.; Baugnet-Mahieu, L.; Rowley, R.

    1987-01-01

    Mouse zygotes (BALB/c blocked in the G 2 phase of the first cell cycle after X-irradiation were allowed to develop in culture medium. Delayed cleavage occurred at the same time in embryos exposed to 1 or 2 Gy and late division coincided with the second division in controls. Two dimensional electrophoresis showed that blocked irradiated embryos underwent the same modifications in protein synthesis as control embryos of the same age, except during first mitosis, for three polypeptide sets of 30, 35 and 45 kilodaltons molecular weight. The most remarkable difference between them was the appearance in cleaving controls of three spots at 35 kilodaltons that were absent in blocked irradiated embryos. It is assumed that blocked embryos 'missed' some signal necessary for cell division, but remained ready to cleave when a second signal occurred. Eggs from the BALB/c strain were particularly susceptible to this effect of X-irradiation but it was also found in eggs from other strains, irradiated with much higher doses. The accompanying comment by Rowley discusses the point of interruption of the control mechanism and the nature of the lesions involved. (author)

  12. Metabolic regulation of neuronal plasticity by the energy sensor AMPK.

    Directory of Open Access Journals (Sweden)

    Wyatt B Potter

    Full Text Available Long Term Potentiation (LTP is a leading candidate mechanism for learning and memory and is also thought to play a role in the progression of seizures to intractable epilepsy. Maintenance of LTP requires RNA transcription, protein translation and signaling through the mammalian Target of Rapamycin (mTOR pathway. In peripheral tissue, the energy sensor AMP-activated Protein Kinase (AMPK negatively regulates the mTOR cascade upon glycolytic inhibition and cellular energy stress. We recently demonstrated that the glycolytic inhibitor 2-deoxy-D-glucose (2DG alters plasticity to retard epileptogenesis in the kindling model of epilepsy. Reduced kindling progression was associated with increased recruitment of the nuclear metabolic sensor CtBP to NRSF at the BDNF promoter. Given that energy metabolism controls mTOR through AMPK in peripheral tissue and the role of mTOR in LTP in neurons, we asked whether energy metabolism and AMPK control LTP. Using a combination of biochemical approaches and field-recordings in mouse hippocampal slices, we show that the master regulator of energy homeostasis, AMPK couples energy metabolism to LTP expression. Administration of the glycolytic inhibitor 2-deoxy-D-glucose (2DG or the mitochondrial toxin and anti-Type II Diabetes drug, metformin, or AMP mimetic AICAR results in activation of AMPK, repression of the mTOR pathway and prevents maintenance of Late-Phase LTP (L-LTP. Inhibition of AMPK by either compound-C or the ATP mimetic ara-A rescues the suppression of L-LTP by energy stress. We also show that enhanced LTP via AMPK inhibition requires mTOR signaling. These results directly link energy metabolism to plasticity in the mammalian brain and demonstrate that AMPK is a modulator of LTP. Our work opens up the possibility of using modulators of energy metabolism to control neuronal plasticity in diseases and conditions of aberrant plasticity such as epilepsy.

  13. Plastic surgery in Nigeria-Scope and challenges

    Directory of Open Access Journals (Sweden)

    TOG Chukwuanukwu

    2011-01-01

    Full Text Available Background Plastic surgery as a major subspecialty of surgery has existed in Nigeria for several decades but the populace including medical practitioners are yet to fully appreciate its scope. This leads to very late presentation/referral of cases and management of cases that should have been referred by less qualified practitioners with attendant poor outcomes and complications. Most people still regard plastic surgery as being synonymous with cosmetic/aesthetic surgery but the scope goes far beyond this entity. It is therefore important that the public including medical practitioners who are the main sources of referral to the subspecialty are aware of the range of cases handled by plastic surgery units. The plastic surgeon in Nigeria is also faced with a lot of challenges ranging from the arduous task of one having to manage very many different and complicated cases to being very poorly equipped and appreciated. Objectives To educate the populace especially the medical practitioners on the scope of plastic surgery and the extent of development of the subspecialty in Nigeria and solicit for colleague′s cooperation in order to move plastic surgery forward. To also highlight the difficulties faced by the plastic surgeon in Nigeria and seeking help from appropriate quarters which will help to reduce unnecessary referrals abroad while improving the services rendered to patients locally. Conclusion Plastic surgery in Nigeria has developed significantly both in scope and manpower but it is still faced with a lot of challenges. Knowledge of its scope will help to reduce unnecessary referrals abroad while improving services/skill here in Nigeria.

  14. 7T T-2*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease

    NARCIS (Netherlands)

    van Rooden, S.; Doan, N.T.; Versluis, M.J.; Goos, J.D.C.; Webb, A.G.; Oleksik, A.M.; van der Flier, W.M.; Scheltens, P.; Barkhof, F.; Weverlinge-Rynsburger, A.W.E.; Blauw, G. J.; Reiber, J.H.C.; van Buchem, M.A.; Milles, J.; van der Grond, J.

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T

  15. Neurogenesis, Exercise, and Cognitive Late Effects of Pediatric Radiotherapy

    Directory of Open Access Journals (Sweden)

    Shaefali P. Rodgers

    2013-01-01

    Full Text Available Brain cancer is a common type of childhood malignancy, and radiotherapy (RT is a mainstay of treatment. RT is effective for tumor eradication, and survival rates are high. However, RT damages the brain and disrupts ongoing developmental processes, resulting in debilitating cognitive “late” effects that may take years to fully manifest. These late effects likely derive from a long-term decrement in cell proliferation, combined with a neural environment that is hostile to plasticity, both of which are induced by RT. Long-term suppression of cell proliferation deprives the brain of the raw materials needed for optimum cognitive performance (such as new neurons in the hippocampus and new glia in frontal cortex, while chronic inflammation and dearth of trophic substances (such as growth hormone limit neuroplastic potential in existing circuitry. Potential treatments for cognitive late effects should address both of these conditions. Exercise represents one such potential treatment, since it has the capacity to enhance cell proliferation, as well as to promote a neural milieu permissive for plasticity. Here, we review the evidence that cognitive late effects can be traced to RT-induced suppression of cell proliferation and hostile environmental conditions, as well as emerging evidence that exercise may be effective as an independent or adjuvant therapy.

  16. Feasibility of self-gated isotropic radial late-phase MR imaging of the liver

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Jakob; Taron, Jana; Othman, Ahmed E.; Kuendel, Matthias; Martirosian, Petros; Ruff, Christer; Schraml, Christina; Nikolaou, Konstantin; Notohamiprodjo, Mike [Eberhard Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Grimm, Robert [Siemens Healthcare MR, Erlangen (Germany)

    2017-03-15

    To evaluate feasibility of a 3D-isotropic self-gated radial volumetric interpolated breath-hold examination (VIBE) for late-phase MRI of the liver. 70 patients were included and underwent liver MRI at 1.5 T. Depending on the diagnosis, either Gd-EOB-DTPA (35 patients) or gadobutrol (35 patients) were administered. During late (gadobutrol) or hepatocyte-specific phase (Gd-EOB-DTPA), a radial prototype sequence was acquired and reconstructed using (1) self-gating with 40 % acceptance (rVIBE{sub 40}); (2) with 100 % acceptance of the data (rVIBE{sub 100}) and compared to Cartesian VIBE (cVIBE). Images were assessed qualitatively (image quality, lesion conspicuity, artefacts; 5-point Likert-scale: 5 = excellent; two independent readers) and quantitatively (coefficient-of-variation (CV); contrast-ratio) in axial and coronal reformations. In eight cases only rVIBE provided diagnostic image quality. Image quality of rVIBE{sub 40} was rated significantly superior (p < 0.05) in Gd-EOB-DTPA-enhanced and coronal reformatted examinations as compared to cVIBE. Lesion conspicuity was significantly improved (p < 0.05) in coronal reformatted Gd-EOB-DTPA-enhanced rVIBE{sub 40} in comparison to cVIBE. CV was higher in rVIBE{sub 40} as compared to rVIBE{sub 100}/cVIBE (p < 0.01). Gadobutrol-enhanced rVIBE{sub 40} and cVIBE showed higher contrast-ratios than rVIBE{sub 100} (p < 0.001), whereas no differences were found in Gd-EOB-DTPA-enhanced examinations. Self-gated 3D-isotropic rVIBE provides significantly superior image quality compared to cVIBE, especially in multiplanar reformatted and Gd-EOB-DTPA-enhanced examinations. (orig.)

  17. Feasibility of self-gated isotropic radial late-phase MR imaging of the liver

    International Nuclear Information System (INIS)

    Weiss, Jakob; Taron, Jana; Othman, Ahmed E.; Kuendel, Matthias; Martirosian, Petros; Ruff, Christer; Schraml, Christina; Nikolaou, Konstantin; Notohamiprodjo, Mike; Grimm, Robert

    2017-01-01

    To evaluate feasibility of a 3D-isotropic self-gated radial volumetric interpolated breath-hold examination (VIBE) for late-phase MRI of the liver. 70 patients were included and underwent liver MRI at 1.5 T. Depending on the diagnosis, either Gd-EOB-DTPA (35 patients) or gadobutrol (35 patients) were administered. During late (gadobutrol) or hepatocyte-specific phase (Gd-EOB-DTPA), a radial prototype sequence was acquired and reconstructed using (1) self-gating with 40 % acceptance (rVIBE_4_0); (2) with 100 % acceptance of the data (rVIBE_1_0_0) and compared to Cartesian VIBE (cVIBE). Images were assessed qualitatively (image quality, lesion conspicuity, artefacts; 5-point Likert-scale: 5 = excellent; two independent readers) and quantitatively (coefficient-of-variation (CV); contrast-ratio) in axial and coronal reformations. In eight cases only rVIBE provided diagnostic image quality. Image quality of rVIBE_4_0 was rated significantly superior (p < 0.05) in Gd-EOB-DTPA-enhanced and coronal reformatted examinations as compared to cVIBE. Lesion conspicuity was significantly improved (p < 0.05) in coronal reformatted Gd-EOB-DTPA-enhanced rVIBE_4_0 in comparison to cVIBE. CV was higher in rVIBE_4_0 as compared to rVIBE_1_0_0/cVIBE (p < 0.01). Gadobutrol-enhanced rVIBE_4_0 and cVIBE showed higher contrast-ratios than rVIBE_1_0_0 (p < 0.001), whereas no differences were found in Gd-EOB-DTPA-enhanced examinations. Self-gated 3D-isotropic rVIBE provides significantly superior image quality compared to cVIBE, especially in multiplanar reformatted and Gd-EOB-DTPA-enhanced examinations. (orig.)

  18. Global change and the evolution of phenotypic plasticity in plants.

    Science.gov (United States)

    Matesanz, Silvia; Gianoli, Ernesto; Valladares, Fernando

    2010-09-01

    Global change drivers create new environmental scenarios and selective pressures, affecting plant species in various interacting ways. Plants respond with changes in phenology, physiology, and reproduction, with consequences for biotic interactions and community composition. We review information on phenotypic plasticity, a primary means by which plants cope with global change scenarios, recommending promising approaches for investigating the evolution of plasticity and describing constraints to its evolution. We discuss the important but largely ignored role of phenotypic plasticity in range shifts and review the extensive literature on invasive species as models of evolutionary change in novel environments. Plasticity can play a role both in the short-term response of plant populations to global change as well as in their long-term fate through the maintenance of genetic variation. In new environmental conditions, plasticity of certain functional traits may be beneficial (i.e., the plastic response is accompanied by a fitness advantage) and thus selected for. Plasticity can also be relevant in the establishment and persistence of plants in novel environments that are crucial for populations at the colonizing edge in range shifts induced by climate change. Experimental studies show taxonomically widespread plastic responses to global change drivers in many functional traits, though there is a lack of empirical support for many theoretical models on the evolution of phenotypic plasticity. Future studies should assess the adaptive value and evolutionary potential of plasticity under complex, realistic global change scenarios. Promising tools include resurrection protocols and artificial selection experiments. © 2010 New York Academy of Sciences.

  19. Fatigue Damage Evaluation of Short Carbon Fiber Reinforced Plastics Based on Phase Information of Thermoelastic Temperature Change.

    Science.gov (United States)

    Shiozawa, Daiki; Sakagami, Takahide; Nakamura, Yu; Nonaka, Shinichi; Hamada, Kenichi

    2017-12-06

    Carbon fiber-reinforced plastic (CFRP) is widely used for structural members of transportation vehicles such as automobile, aircraft, or spacecraft, utilizing its excellent specific strength and specific rigidity in contrast with the metal. Short carbon fiber composite materials are receiving a lot of attentions because of their excellent moldability and productivity, however they show complicated behaviors in fatigue fracture due to the random fibers orientation. In this study, thermoelastic stress analysis (TSA) using an infrared thermography was applied to evaluate fatigue damage in short carbon fiber composites. The distribution of the thermoelastic temperature change was measured during the fatigue test, as well as the phase difference between the thermoelastic temperature change and applied loading signal. Evolution of fatigue damage was detected from the distribution of thermoelastic temperature change according to the thermoelastic damage analysis (TDA) procedure. It was also found that fatigue damage evolution was more clearly detected than before by the newly developed thermoelastic phase damage analysis (TPDA) in which damaged area was emphasized in the differential phase delay images utilizing the property that carbon fiber shows opposite phase thermoelastic temperature change.

  20. Onset age of L2 acquisition influences language network in early and late Cantonese-Mandarin bilinguals.

    Science.gov (United States)

    Liu, Xiaojin; Tu, Liu; Wang, Junjing; Jiang, Bo; Gao, Wei; Pan, Ximin; Li, Meng; Zhong, Miao; Zhu, Zhenzhen; Niu, Meiqi; Li, Yanyan; Zhao, Ling; Chen, Xiaoxi; Liu, Chang; Lu, Zhi; Huang, Ruiwang

    2017-11-01

    Early second language (L2) experience influences the neural organization of L2 in neuro-plastic terms. Previous studies tried to reveal these plastic effects of age of second language acquisition (AoA-L2) and proficiency-level in L2 (PL-L2) on the neural basis of language processing in bilinguals. Although different activation patterns have been observed during language processing in early and late bilinguals by task-fMRI, few studies reported the effect of AoA-L2 and high PL-L2 on language network at resting state. In this study, we acquired resting-state fMRI (R-fMRI) data from 10 Cantonese (L1)-Mandarin (L2) early bilinguals (acquired L2: 3years old) and 11 late bilinguals (acquired L2: 6years old), and analyzed their topological properties of language networks after controlling the language daily exposure and usage as well as PL in L1 and L2. We found that early bilinguals had significantly a higher clustering coefficient, global and local efficiency, but significantly lower characteristic path length compared to late bilinguals. Modular analysis indicated that compared to late bilinguals, early bilinguals showed significantly stronger intra-modular functional connectivity in the semantic and phonetic modules, stronger inter-modular functional connectivity between the semantic and phonetic modules as well as between the phonetic and syntactic modules. Differences in global and local parameters may reflect different patterns of neuro-plasticity respectively for early and late bilinguals. These results suggested that different L2 experience influences topological properties of language network, even if late bilinguals achieve high PL-L2. Our findings may provide a new perspective of neural mechanisms related to early and late bilinguals. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Quadrature entanglement and photon-number correlations accompanied by phase-locking

    International Nuclear Information System (INIS)

    Adamyan, H. H.; Manvelyan, S. B.; Adamyan, N. H.; Kryuchkyan, G. Yu.

    2006-01-01

    We investigate quantum properties of phase-locked light beams generated in a nondegenerate optical parametric oscillator (NOPO) with an intracavity waveplate. This investigation continues our previous analysis presented in Phys. Rev. A 69, 053814 (2004), and involves problems of continuous-variable quadrature entanglement in the spectral domain, photon-number correlations as well as the signatures of phase-locking in the Wigner function. We study the role of phase-localizing processes on the quantum correlation effects. The peculiarities of phase-locked NOPO in the self-pulsing instability operational regime are also cleared up. The results are obtained in the P-representation as a quantum-mechanical calculation in the framework of stochastic equations of motion, as well as by numerical simulation based on the method of quantum state diffusion

  2. Unsupervised learning by spike timing dependent plasticity in phase change memory (PCM synapses

    Directory of Open Access Journals (Sweden)

    Stefano eAmbrogio

    2016-03-01

    Full Text Available We present a novel one-transistor/one-resistor (1T1R synapse for neuromorphic networks, based on phase change memory (PCM technology. The synapse is capable of spike-timing dependent plasticity (STDP, where gradual potentiation relies on set transition, namely crystallization, in the PCM, while depression is achieved via reset or amorphization of a chalcogenide active volume. STDP characteristics are demonstrated by experiments under variable initial conditions and number of pulses. Finally, we support the applicability of the 1T1R synapse for learning and recognition of visual patterns by simulations of fully connected neuromorphic networks with 2 or 3 layers with high recognition efficiency. The proposed scheme provides a feasible low-power solution for on-line unsupervised machine learning in smart reconfigurable sensors.

  3. Motor Training Promotes Both Synaptic and Intrinsic Plasticity of Layer II/III Pyramidal Neurons in the Primary Motor Cortex.

    Science.gov (United States)

    Kida, Hiroyuki; Tsuda, Yasumasa; Ito, Nana; Yamamoto, Yui; Owada, Yuji; Kamiya, Yoshinori; Mitsushima, Dai

    2016-08-01

    Motor skill training induces structural plasticity at dendritic spines in the primary motor cortex (M1). To further analyze both synaptic and intrinsic plasticity in the layer II/III area of M1, we subjected rats to a rotor rod test and then prepared acute brain slices. Motor skill consistently improved within 2 days of training. Voltage clamp analysis showed significantly higher α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/N-methyl-d-aspartate (AMPA/NMDA) ratios and miniature EPSC amplitudes in 1-day trained rats compared with untrained rats, suggesting increased postsynaptic AMPA receptors in the early phase of motor learning. Compared with untrained controls, 2-days trained rats showed significantly higher miniature EPSC amplitude and frequency. Paired-pulse analysis further demonstrated lower rates in 2-days trained rats, suggesting increased presynaptic glutamate release during the late phase of learning. One-day trained rats showed decreased miniature IPSC frequency and increased paired-pulse analysis of evoked IPSC, suggesting a transient decrease in presynaptic γ-aminobutyric acid (GABA) release. Moreover, current clamp analysis revealed lower resting membrane potential, higher spike threshold, and deeper afterhyperpolarization in 1-day trained rats-while 2-days trained rats showed higher membrane potential, suggesting dynamic changes in intrinsic properties. Our present results indicate dynamic changes in glutamatergic, GABAergic, and intrinsic plasticity in M1 layer II/III neurons after the motor training. © The Author 2016. Published by Oxford University Press.

  4. Views of college students on plastic surgery.

    Science.gov (United States)

    Ahmad, Muhammad; Mohmand, Humayun; Ahmad, Nabila

    2013-06-01

    Various studies have been conducted in many countries to determine the perception/awareness about plastic surgery. The present study assessed the views of college students about plastic surgery. A questionnaire consisted of nine questions regarding the basic knowledge about plastic surgery was randomly distributed among college students. The students were given 20 minutes to fill out the forms. A total of 250 male and 250 female college students were randomly included in the study. The mean age of the male students was 21.1 years as compared to 20.7 years of female students. The top five conditions named were related to hair (89.8%) followed by face scars (88%). The most common procedure named by the students was liposuction (88.2%) followed by hair transplantation. 80.2% of the students opted not to be a plastic surgeon if given an opportunity to select the profession. 33.8% of the students had seen some kinds of plastic surgery operation. Only 5.6% of the students (3.4% male and 2.2% female) had seen some kinds of plastic surgery procedure. 68% of male students and 48% of female students wished to have a plastic surgery procedure sometime in their lives. Majority of the students (88%) got the information from the internet. The second most common source was magazines (85.2%). Majority of the students (53.4%) had an idea of an invisible scar as a result of having a plastic surgery procedure. Only 22% thought to have no scar. Late Michael Jackson was at the top of the list of celebrities having a plastic surgery procedure (97.8%) followed by Nawaz Shariff (92.4%). Despite the rapid growth of plastic surgery in the last two decades, a large portion of population remains unaware of the spatiality. It is essential to institute programs to educate healthcare consumers and providers about the plastic surgery.

  5. Visual and Plastic Arts in Teaching Literacy: Null Curricula?

    Science.gov (United States)

    Wakeland, Robin Gay

    2010-01-01

    Visual and plastic arts in contemporary literacy instruction equal null curricula. Studies show that painting and sculpture facilitate teaching reading and writing (literacy), yet such pedagogy has not been formally adopted into USA curriculum. An example of null curriculum can be found in late 19th - early 20th century education the USA…

  6. Peripheral Sensory Deprivation Restores Critical-Period-like Plasticity to Adult Somatosensory Thalamocortical Inputs

    Directory of Open Access Journals (Sweden)

    Seungsoo Chung

    2017-06-01

    Full Text Available Recent work has shown that thalamocortical (TC inputs can be plastic after the developmental critical period has closed, but the mechanism that enables re-establishment of plasticity is unclear. Here, we find that long-term potentiation (LTP at TC inputs is transiently restored in spared barrel cortex following either a unilateral infra-orbital nerve (ION lesion, unilateral whisker trimming, or unilateral ablation of the rodent barrel cortex. Restoration of LTP is associated with increased potency at TC input and reactivates anatomical map plasticity induced by whisker follicle ablation. The reactivation of TC LTP is accompanied by reappearance of silent synapses. Both LTP and silent synapse formation are preceded by transient re-expression of synaptic GluN2B-containing N-methyl-D-aspartate (NMDA receptors, which are required for the reappearance of TC plasticity. These results clearly demonstrate that peripheral sensory deprivation reactivates synaptic plasticity in the mature layer 4 barrel cortex with features similar to the developmental critical period.

  7. Mapracorat, a selective glucocorticoid receptor agonist, causes apoptosis of eosinophils infiltrating the conjunctiva in late-phase experimental ocular allergy

    Directory of Open Access Journals (Sweden)

    Baiula M

    2014-06-01

    Full Text Available Monica Baiula,1 Andrea Bedini,1 Jacopo Baldi,1 Megan E Cavet,2 Paolo Govoni,3 Santi Spampinato11Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy; 2Global Pharmaceutical R&D, Bausch & Lomb Inc., Rochester, NY, USA; 3Department of Biomedical, Biotechnological and Translational Sciences, University of Parma, Parma, ItalyBackground: Mapracorat, a novel nonsteroidal selective glucocorticoid receptor agonist, has been proposed for the topical treatment of inflammatory disorders as it binds with high affinity and selectivity to the human glucocorticoid receptor and displays a potent anti-inflammatory activity, but seems to be less effective in transactivation of a number of genes, resulting in a lower potential for side effects. Contrary to classical glucocorticoids, mapracorat displays a reduced ability to increase intraocular pressure and in inducing myocilin, a protein linked to intraocular pressure elevation. Allergic conjunctivitis is the most common form of ocular allergy and can be divided into an early phase, developing immediately after allergen exposure and driven primarily by mast cell degranulation, and a late phase, developing from 6–10 hours after the antigen challenge, and characterized by conjunctival infiltration of eosinophils and other immune cells as well as by the production of cytokines and chemokines.Methods: In this study, mapracorat was administered into the conjunctival sac of ovalbumin (OVA-sensitized guinea pigs 2 hours after the induction of allergic conjunctivitis, with the aim of investigating its activity in reducing clinical signs of the late-phase ocular reaction and to determine its mechanism of anti-allergic effects with respect to apoptosis of conjunctival eosinophils and expression of the chemokines C-C motif ligand 5 (CCL5, C-C motif ligand 11 (CCL11, and interleukin-8 (IL-8 and the proinflammatory cytokines interleukin-1β (IL-1β and tumor necrosis factor-α (TNF

  8. Plasticity enhancement mechanisms in refractory metals and intermetallics

    International Nuclear Information System (INIS)

    Gibala, R.; Chang, H.; Czarnik, C.M.; Edwards, K.M.; Misra, A.

    1993-01-01

    Plasticity enhancement associated with surface films and precipitates or dispersoids in bcc refractory metals is operative in ordered intermetallic compounds. Some results are given for NiAl and MoSi 2 -based materials. The monotonic and cyclic plasticity of NiAl at room temperature can be enhanced by surface films. Ductile second phases also enhance the plasticity of NiAl. MoSi 2 exhibits similar effects of surface films and dispersoids, but primarily at elevated temperatures. The plasticity enhancement is associated with enhanced dislocation generation from constrained deformation at the film-substrate or precipitate/dispersoid-matrix interface of the composite systems

  9. Late quaternary environmental changes in the upper Las Vegas valley, Nevada

    Science.gov (United States)

    Quade, Jay

    1986-11-01

    Five stratigraphic units and five soils of late Pleistocene to Holocene age crop out in dissected badlands on Corn Creek Flat, 30 km northwest of Las Vegas, Nevada, and at Tule Springs, nearer to Las Vegas. The record is dominantly fluvial but contains evidence of several moister, marsh-forming periods: the oldest (Unit B) dates perhaps to the middle Wisconsin, and the more widespread Unit D falls between 30,000 and 15,000 yr B.P. Unit D therefore correlates with pluvial maximum lacustrine deposits elsewhere in the Great Basin. Standing water was not of sufficient depth or extent during either period to form lake strandlines. Between 14,000 and 7200 yr B.P. (Unit E), standing surface water gradually decreased, a trend also apparent in Great Basin pluvial lake chronologies during the same period. Groundwater carbonate cementation and burrowing by cicadas (Cicadae) accompany the moist-phase units. After 7200 yr B.P., increased wind action, decreased biotic activity, and at least 25 m of water-table lowering accompanied widespread erosion of older fine-grained deposits. Based on pack-rat midden and pollen evidence, this coincides with major vegetation changes in the valley, from sagebrush-dominated steppe to lower Mohave desertscrub.

  10. Translation-rotation plasticity as basic mechanism of plastic deformation in macro-, micro- and nanoindentation processes

    International Nuclear Information System (INIS)

    Grabco, D; Shikimaka, O; Harea, E

    2008-01-01

    This paper presents a brief review of multilateral examinations for the purpose of detection of interrelation between processes occuring in solids at different levels of action of exterior loading, namely, at macro-, micro- and nanoindentation. Convincing arguments supporting the rotation deformation mechanism alongside the recognized dislocation one are adduced. It has been shown that the decrease in dislocation mobility leads at all scales to the intensification of rotation plasticity and to the involvement of other plastic deformation mechanisms, such as appearance and interaction of disclinations, twinning, phase transition and compression of material. The conversion from translation plasticity to the rotation-translation one means transition to the higher level of plastic deformation, the mesolevel, when the possibilities of the previous microscopic level are exhausted. It was established that the plastic deformation zone in the vicinity of indentations could be separated into two main specific regions: (i) peripheral region predominantly with the dislocation deformation mechanism; otherwise, translation mechanism: microlevel, and (ii) quasidestructured region mainly with the disclination or the intergranular sliding mechanism: rotation mechanism, mesolevel

  11. Global plastic surgeons images depicted in motion pictures.

    Science.gov (United States)

    Hwang, Se Jin; Park, Sowhey; Hwang, Kun

    2013-03-01

    Motion pictures are made to entertain and enlighten people, but they are viewed differently by different people. What one considers to be a tearjerker may induce giggles in another. We have gained added interest in this because our professional pictures contain plastic surgery in their venue. We have recently reviewed 21 motion pictures that were made from 1928 to 2006 and that includes plastic surgical procedures in their content. As a habit, we tried to analyze them from a surgical point of view. About one third (35.7%) of the patients were criminals, whereas 14.3% of them were spies. One third of the procedures were done by illegitimate "surgeons," whereas a quarter of the procedures (25%) were performed by renowned surgeons. Surgeons who were in love with the patients did the rest (25%) of the operations. The complication rate was 14.3%; the surgery was successful in 85.7% of cases, but were the patients happy with the results? This was not the case in the movies. Only 7.7% were happy; 14.5 % of them were eminently unhappy. Why the discrepancy? It is difficult to analyze the minds of the people in the film, but considering that the majority of the characters in the films were rather unsavory, one may deduce that a crooked mind functions differently. Motion pictures have advanced greatly in the past several decades with the advent of improved mechanical and electronic devices, and plastic surgery as also advanced in tandem. This surgical field has become a common procedure in our daily life. It is readily available and mostly painless. However, the public sees it in only one way, that is, that the performing physicians are highly compensated. Very few consider the efforts and the suffering that accompanies each and every surgical procedure as it is performed. Perhaps, it is too much to hope for a day that will come when we will see a film that portrays the mental anguish that accompanies each and every procedure the plastic surgeon makes.

  12. Developmental phenotypic plasticity helps bridge stochastic weather events associated with climate change.

    Science.gov (United States)

    Burggren, Warren

    2018-05-10

    The slow, inexorable rise in annual average global temperatures and acidification of the oceans are often advanced as consequences of global change. However, many environmental changes, especially those involving weather (as opposed to climate), are often stochastic, variable and extreme, particularly in temperate terrestrial or freshwater habitats. Moreover, few studies of animal and plant phenotypic plasticity employ realistic (i.e. short-term, stochastic) environmental change in their protocols. Here, I posit that the frequently abrupt environmental changes (days, weeks, months) accompanying much longer-term general climate change (e.g. global warming over decades or centuries) require consideration of the true nature of environmental change (as opposed to statistical means) coupled with an expansion of focus to consider developmental phenotypic plasticity. Such plasticity can be in multiple forms - obligatory/facultative, beneficial/deleterious - depending upon the degree and rate of environmental variability at specific points in organismal development. Essentially, adult phenotypic plasticity, as important as it is, will be irrelevant if developing offspring lack sufficient plasticity to create modified phenotypes necessary for survival. © 2018. Published by The Company of Biologists Ltd.

  13. The dependence of granular plasticity on particle shape

    Science.gov (United States)

    Murphy, Kieran; Jaeger, Heinrich

    Granular materials plastically deform through reworking an intricate network of particle-particle contacts. Some particle rearrangements have only a fleeting effect before being forgotten while others set in motion global restructuring. How particle shape affects local interactions and how those, in turn, influence the nature of the aggregate's plasticity is far from clear, especially in three dimensions. Here we investigate the remarkably wide range of behaviors in the yielding regime, from quiescent flow to violent jerks, depending on particle shape. We study this complex dependence via uniaxial compression experiments on aggregates of 3D-printed particles, and complement stress-strain data with simultaneous x-ray videos and volumetric strain measurements. We find power law distributions of the slip magnitudes, and discuss their universality. Our data show that the multitude of small slips serves to gradually dilate the packing whereas the fewer large ones accompany significant compaction events. Our findings provide new insights into general features of granular materials during plastic deformation and highlight how small changes in particle shape can give rise to drastic differences in yielding behavior.

  14. Plastics - the sustainable way to use Oil and Gas

    Energy Technology Data Exchange (ETDEWEB)

    Siebourg, Wolfgang

    2009-07-01

    Conclusions (drawn by the author): Plastics are a sustainable use of oil and gas - Plastic products enable significant savings of energy and GHG emissions particularly in the use phase; - Plastic products help use resources in the most efficient way. Restricting plastics relative growth would result in increased energy consumption. Diversion from landfill would increase resource efficiency. Waste-to-Energy is an additional resource and is complementary to mechanical recycling. Plastics producers and the Oil and Gas industry should cooperate to produce reliable consumption data. Oil and Gas industry should develop and maintain European (world) eco-profiles (cradle to gate) for their respective industry. (author)

  15. Phase Transformation of Metastable Austenite in Steel during Nano indentation

    International Nuclear Information System (INIS)

    Ahn, Taehong; Lee, Sung Bo; Han, Heung Nam; Park, Kyungtae

    2013-01-01

    These can produce geometrical softening accompanied by a sudden displacement excursion during load-controlled nanoindentation, which referred to in the literature as a pop-in. In this study, phase transformation of metastable austenite to stress-induced ε martensite which causes pop-ins during nanoindentation of steel will be reported and discussed. This study investigated the relationship between pop-in behavior of austenite in the early stage of nanoindentation and formation of ε martensite based on microstructural analyses. The load-displacement curve obtained from nanoindentation revealed stepwise pop-ins in the early stage of plastic deformation. From analyses of high resolution TEM images, a cluster of banded structure under the indent turned out a juxtaposition of (111) planes of γ austenite and (0001) planes of ε martensite. The calculation of displacement along indentation axis for (111) slip system by formation of ε martensite showed that geometrical softening can also occur by ε martensite formation when considering that the stress-induced ε martensite transformation is the predominant deformation mode in the early stage of plastic deformation and its monopartial nature as well. These microstructural investigations strongly suggest that the pop-in behavior in the early stage of plastic deformation of austenite is closely related to the formation of ε martensite

  16. Phase Transformation of Metastable Austenite in Steel during Nano indentation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Taehong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Sung Bo; Han, Heung Nam [Seoul National Univ., Seoul (Korea, Republic of); Park, Kyungtae [Hanbat National Univ., Daejeon (Korea, Republic of)

    2013-05-15

    These can produce geometrical softening accompanied by a sudden displacement excursion during load-controlled nanoindentation, which referred to in the literature as a pop-in. In this study, phase transformation of metastable austenite to stress-induced ε martensite which causes pop-ins during nanoindentation of steel will be reported and discussed. This study investigated the relationship between pop-in behavior of austenite in the early stage of nanoindentation and formation of ε martensite based on microstructural analyses. The load-displacement curve obtained from nanoindentation revealed stepwise pop-ins in the early stage of plastic deformation. From analyses of high resolution TEM images, a cluster of banded structure under the indent turned out a juxtaposition of (111) planes of γ austenite and (0001) planes of ε martensite. The calculation of displacement along indentation axis for (111) slip system by formation of ε martensite showed that geometrical softening can also occur by ε martensite formation when considering that the stress-induced ε martensite transformation is the predominant deformation mode in the early stage of plastic deformation and its monopartial nature as well. These microstructural investigations strongly suggest that the pop-in behavior in the early stage of plastic deformation of austenite is closely related to the formation of ε martensite.

  17. Skin manifestations in sulfur mustard exposed victims with ophthalmologic complications: Association between early and late phase

    Directory of Open Access Journals (Sweden)

    Somayeh Hejazi, MD

    Full Text Available Context: Sulfur mustard (SM was used during the Iraq-Iran war (1980–1988. Exposed veterans continue to suffer from its ocular, skin, and respiratory complications. Objective: We aimed to evaluate associations between early (at the time of acute exposure and decades later skin manifestations in individuals with severe ophthalmologic complications secondary to sulfur mustard exposure. Materials and methods: One hundred forty-nine veterans with severe ocular injuries were evaluated for acute and chronic skin complications. Logistic regression models were used to examine the associations between early and late skin manifestations. Results: Late skin complaints were observed in nearly all survivors who had early skin lesions (131 out of 137; 95.62%. Seven out of 12 patients (58.33% who did not have early skin lesions ultimately developed late skin complications. There was a significant relationship between the presence of lesions at the time of exposure and developing late skin complaints (two-sided Fisher's exact test, OR = 15.59, p < 0.001. There was an association between having at least one early skin lesion and occurrence of late skin complications. Survivors with blisters at the time of chemical exposure were more likely to complain of itching (95% CI: 3.63–25.97, p < 0.001, burning (OR = 11.16; 95% CI: 2.97–41.89, p < 0.001, pigmentation changes (OR = 10.17; 95% CI: 2.54–40.75, p = 0.001, dryness (OR = 6.71, 95% CI: 1.22–37.01, p = 0.03 or cherry angioma (OR = 2.59; 95% CI:1.21–5.55, p = 0.01 during the late phase. Using multivariate logistic models, early blisters remained significantly associated with latent skin complaints. Of note, the genitalia and great flexure areas were the most involved anatomical sites for both early and late skin lesions in SM exposed survivors. Conclusion: According to this study, the presence of blisters at the time of exposure to SM is the most important predictor of developing

  18. Root plasticity buffers competition among plants: theory meets experimental data.

    Science.gov (United States)

    Schiffers, Katja; Tielbörger, Katja; Tietjen, Britta; Jeltsch, Florian

    2011-03-01

    Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on resource acquisition, plasticity has been generally neglected in previous empirical and theoretical studies estimating interaction intensity among plants. In this study, we developed a semi-mechanistic model that addresses this shortcoming by introducing the idea of compensatory growth into the classical-zone-of influence (ZOI) and field-of-neighborhood (FON) approaches. The model parameters describing the belowground plastic sphere of influence (PSI) were parameterized using data from an accompanying field experiment. Measurements of the uptake of a stable nutrient analogue at distinct distances to the neighboring plants showed that the study species responded plastically to belowground competition by avoiding overlap of individuals' rhizospheres. An unexpected finding was that the sphere of influence of the study species Bromus hordeaceus could be best described by a unimodal function of distance to the plant's center and not with a continuously decreasing function as commonly assumed. We employed the parameterized model to investigate the interplay between plasticity and two other important factors determining the intensity of competitive interactions: overall plant density and the distribution of individuals in space. The simulation results confirm that the reduction of competition intensity due to morphological plasticity strongly depends on the spatial structure of the competitive environment. We advocate the use of semi-mechanistic simulations that explicitly consider morphological plasticity to improve our mechanistic understanding of plant interactions.

  19. Protective actions in the late phase - Intervention criteria and decision-making

    International Nuclear Information System (INIS)

    Hedemann-Jensen, P.

    2004-01-01

    Major countermeasures in the late phase of a nuclear or radiological accident where long-lived radionuclides have been dispersed in the environment are relocation/resettlement, foodstuff restrictions, agricultural countermeasures and clean-up of contaminated areas. There has essentially been a broad acceptance internationally of the principles for their introduction, but it has not been possible to reach an agreement for the purpose of defining a net benefit based upon the exact weighting to be attached to each of the attributes influencing the decision on intervention, e.g. socio-psychological attributes. Optimisation of protection, i.e. maximising the net benefit, is not a question of developing radiation protection philosophy to fully include socio-psychological factors but rather to include these factors - in parallel with the radiological protection factors - in cooperation between radiation protection experts and e.g. experts in social and psychological sciences under the responsibility of the decision-maker, who will take the final decision on the introduction of long-term countermeasures. (authors)

  20. Plastic

    International Nuclear Information System (INIS)

    Jeong Gi Hyeon

    1987-04-01

    This book deals with plastic, which includes introduction for plastic, chemistry of high polymers, polymerization, speciality and structure of a high molecule property of plastic, molding, thermosetting plastic, such as polyethylene, polyether, polyamide and polyvinyl acetyl, thermal plastic like phenolic resins, xylene resins, melamine resin, epoxy resin, alkyd resin and poly urethan resin, new plastic like ionomer and PPS resin, synthetic laminated tape and synthetic wood, mixed materials in plastic, reprocessing of waste plastic, polymer blend, test method for plastic materials and auxiliary materials of plastic.

  1. The Plastic Surgery Hand Curriculum.

    Science.gov (United States)

    Silvestre, Jason; Levin, L Scott; Serletti, Joseph M; Chang, Benjamin

    2015-12-01

    Designing an effective hand rotation for plastic surgery residents is difficult. The authors address this limitation by elucidating the critical components of the hand curriculum during plastic surgery residency. Hand questions on the Plastic Surgery In-Service Training Exam for six consecutive years (2008 to 2013) were characterized by presence of imaging, vignette setting, question taxonomy, answer domain, anatomy, and topic. Answer references were quantified by source and year of publication. Two hundred sixty-six questions were related to hand surgery (22.7 percent of all questions; 44.3 per year) and 61 were accompanied by an image (22.9 percent). Vignettes tended to be clinic- (50.0 percent) and emergency room-based (35.3 percent) (p < 0.001). Questions required decision-making (60.5 percent) over interpretation (25.9 percent) and recall skills (13.5 percent) (p < 0.001). Answers focused on interventions (57.5 percent) over anatomy/pathology (25.2 percent) and diagnoses (17.3 percent) (p < 0.001). Nearly half of the questions focused on the digits. The highest yield topics were trauma (35.3 percent), reconstruction (24.4 percent), and aesthetic and functional problems (14.2 percent). The Journal of Hand Surgery (American volume) (20.5 percent) and Plastic and Reconstructive Surgery (18.0 percent) were the most-cited journals, and the median publication lag was 7 years. Green's Operative Hand Surgery was the most-referenced textbook (41.8 percent). These results will enable trainees to study hand surgery topics with greater efficiency. Faculty can use these results to ensure that tested topics are covered during residency training. Thus, a benchmark is established to improve didactic, clinical, and operative experiences in hand surgery.

  2. Decrease in early right alpha band phase synchronization and late gamma band oscillations in processing syntax in music.

    Science.gov (United States)

    Ruiz, María Herrojo; Koelsch, Stefan; Bhattacharya, Joydeep

    2009-04-01

    The present study investigated the neural correlates associated with the processing of music-syntactical irregularities as compared with regular syntactic structures in music. Previous studies reported an early ( approximately 200 ms) right anterior negative component (ERAN) by traditional event-related-potential analysis during music-syntactical irregularities, yet little is known about the underlying oscillatory and synchronization properties of brain responses which are supposed to play a crucial role in general cognition including music perception. First we showed that the ERAN was primarily represented by low frequency (music-syntactical irregularities as compared with music-syntactical regularities, were associated with (i) an early decrease in the alpha band (9-10 Hz) phase synchronization between right fronto-central and left temporal brain regions, and (ii) a late ( approximately 500 ms) decrease in gamma band (38-50 Hz) oscillations over fronto-central brain regions. These results indicate a weaker degree of long-range integration when the musical expectancy is violated. In summary, our results reveal neural mechanisms of music-syntactic processing that operate at different levels of cortical integration, ranging from early decrease in long-range alpha phase synchronization to late local gamma oscillations. 2008 Wiley-Liss, Inc.

  3. Some remarks on the transitional phase between Early Roman and Late Roman Periods in the region north of the Middle Danube

    Czech Academy of Sciences Publication Activity Database

    Tejral, Jaroslav

    2015-01-01

    Roč. 56, č. 2 (2015), s. 43-101 ISSN 1211-7250 Institutional support: RVO:68081758 Keywords : Early and Late Roman Period * transitional phase * Marcomanic Wars and their aftermath * ethnical and social backround of the B2/C1 phase Subject RIV: AC - Archeology, Anthropology, Ethnology http://prehled-vyzkumu.arub.avcr.cz/miranda2/export/sitesavcr/arub-prehled-vyzkumu/prehled-cisel-a-clanku/prehled-vydanych-cisel/files/PV56_2_Studie2_Tejral.pdf

  4. Transformation-induced plasticity in multiphase steels subjected to thermomechanical loading

    NARCIS (Netherlands)

    Tjahjanto, D.D.; Turteltaub, S.R.; Suiker, A.S.J.; Zwaag, van der S.

    2008-01-01

    The behaviour of transformation-induced plasticity steels subjected to combined thermomechanical loading is studied at the microscale by means of numerical simulations. The microstructure is composed of an austenitic phase that may deform plastically and/or transform into martensite, and a ferritic

  5. Effect of volume change of coal during plastic and resolidifying phase on the internal gas pressure in coke ovens; Sekitan nanka saikoka katei ni okeru taiseki henka ga cokes ro no nanka yoyu sonai gas atsu ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, S; Arima, T [Nippon Steel Corp., Tokyo (Japan)

    2000-08-01

    The coking pressure in coke oven, which is caused by the internal gas pressure in the coal plastic layer, is determined by the gas permeability of the layer. The gas permeability of the plastic layer depends on its density as well as the physical property of the plastic coal itself The plastic layer is between the coke layer and the coal layer and the effect of the volume change of these outer layers, i.e. contraction and compression, on the density and the internal gas pressure of the plastic layer was studied. Sandwich carbonization test, where different coals were charged in the test coke oven, showed that the internal gas pressure in the plastic layer depends not only on the one kind of coal in plastic phase but also on the other kind of coal in resolidifying phase near the oven walls. The relative volume of coke transformed from the unit volume of coal was measured using X-ray CT scanner and it varied greatly across the coke oven width depending on the kinds of coals. The volume change of coal during plastic and resolidifying phase affects the density and the internal gas pressure of the plastic layer The relative volume of semicoke and coke transformed from the unit volume of coal near the oven walls is higher for a high coking pressure coal than that for a low coking pressure coal. This leads to the high density of the plastic layer and the generation of dangerously high internal gas pressure in the oven centre. (author)

  6. Solid phase radioimmunoassay for plasma testosterone using a plastic microtiter tray

    International Nuclear Information System (INIS)

    Hosogi, Hidemi

    1975-01-01

    In order to simplify radioimmunoassay for plasma testosterone and to measure many samples at the same time, a method of solid phase radioimmunoassay utilizing a plastic disposable microtiter tray (DMT) by which chromatography can be omitted was investigated. Other steroids except for 5α-dihydrotestosterone (5α-DHT) had a low degree of cross reactivity with the antiserum. Five α-DHT which could be measured together with testosterone in this assay was not a problem clinically because of its strong androgenic activity. The best standard curve was obtained when the antiserum was diluted to 1:1000. The sensitivity of this assay was 10 pg-tube. The maximal adsorption of antibody to plastic DMT was observed when the pH of the antiserum was within the range of 6.5-9.5 and the precoating time was 24 hr at room temperature. The best pH of the incubation buffer was 0.8, and the antigen-antibody reaction became a plateau when the incubation exceeded 6 hrs. The water blank in this assay was 4.6 +- 2.1 pg/tube. The recovery of testosterone (50, 100, 200 pg) when added to 0.1 ml female plasma was 99 +- 6.8%. Coefficients of variation within assay and between assays were below 11.2% and 20.0%, respectively. Correlation between this method and the dextran-coated charcoal method was fairly good (r=0.938). Plasma testosterone levels in 10 normal males and 12 normal females were 616 +- 202 (mean +- SD) ng/dl and 66 +- 29 (mean +- SD) ng/dl, respectively. The levels were low in patients with hypopituitarism, hypogonadism and acromegaly. They were normal in patients with Cushing's syndrome due to adrenal hyperplasia and adenoma, but they were high in a patient with adrenal carcinoma. In a patient with testicular feminization, the level was 632 ng/dl. This increased after the administration of HCG, and decreased to 127.5 ng/dl after castration. (auth.)

  7. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  8. Integrative Analysis of Disease Signatures Shows Inflammation Disrupts Juvenile Experience-Dependent Cortical Plasticity

    Science.gov (United States)

    Smith, Milo R.; Burman, Poromendro

    2016-01-01

    Throughout childhood and adolescence, periods of heightened neuroplasticity are critical for the development of healthy brain function and behavior. Given the high prevalence of neurodevelopmental disorders, such as autism, identifying disruptors of developmental plasticity represents an essential step for developing strategies for prevention and intervention. Applying a novel computational approach that systematically assessed connections between 436 transcriptional signatures of disease and multiple signatures of neuroplasticity, we identified inflammation as a common pathological process central to a diverse set of diseases predicted to dysregulate plasticity signatures. We tested the hypothesis that inflammation disrupts developmental cortical plasticity in vivo using the mouse ocular dominance model of experience-dependent plasticity in primary visual cortex. We found that the administration of systemic lipopolysaccharide suppressed plasticity during juvenile critical period with accompanying transcriptional changes in a particular set of molecular regulators within primary visual cortex. These findings suggest that inflammation may have unrecognized adverse consequences on the postnatal developmental trajectory and indicate that treating inflammation may reduce the burden of neurodevelopmental disorders. PMID:28101530

  9. Late postacute neurologic rehabilitation: neuroscience, engineering, and clinical programs.

    Science.gov (United States)

    Bach-y-Rita, Paul

    2003-08-01

    This lecture highlights my career in rehabilitation research. My principal efforts in rehabilitation have been to study (1) mechanisms of brain plasticity related to reorganization of the brain and recovery of function; (2) late postacute rehabilitation; (3) sensory substitution; and (4) rehabilitation engineering. A principal goal has been to aid in the development of a strong scientific base in rehabilitation.

  10. The sedating antidepressant trazodone impairs sleep-dependent cortical plasticity.

    Directory of Open Access Journals (Sweden)

    Sara J Aton

    2009-07-01

    Full Text Available Recent findings indicate that certain classes of hypnotics that target GABA(A receptors impair sleep-dependent brain plasticity. However, the effects of hypnotics acting at monoamine receptors (e.g., the antidepressant trazodone on this process are unknown. We therefore assessed the effects of commonly-prescribed medications for the treatment of insomnia (trazodone and the non-benzodiazepine GABA(A receptor agonists zaleplon and eszopiclone in a canonical model of sleep-dependent, in vivo synaptic plasticity in the primary visual cortex (V1 known as ocular dominance plasticity.After a 6-h baseline period of sleep/wake polysomnographic recording, cats underwent 6 h of continuous waking combined with monocular deprivation (MD to trigger synaptic remodeling. Cats subsequently received an i.p. injection of either vehicle, trazodone (10 mg/kg, zaleplon (10 mg/kg, or eszopiclone (1-10 mg/kg, and were allowed an 8-h period of post-MD sleep before ocular dominance plasticity was assessed. We found that while zaleplon and eszopiclone had profound effects on sleeping cortical electroencephalographic (EEG activity, only trazodone (which did not alter EEG activity significantly impaired sleep-dependent consolidation of ocular dominance plasticity. This was associated with deficits in both the normal depression of V1 neuronal responses to deprived-eye stimulation, and potentiation of responses to non-deprived eye stimulation, which accompany ocular dominance plasticity.Taken together, our data suggest that the monoamine receptors targeted by trazodone play an important role in sleep-dependent consolidation of synaptic plasticity. They also demonstrate that changes in sleep architecture are not necessarily reliable predictors of how hypnotics affect sleep-dependent neural functions.

  11. THE INFLUENCE OF PRE-HEAT TREATMENT ON WHITE CAST IRONS PLASTICITY

    Directory of Open Access Journals (Sweden)

    T. M. Myronova

    2013-11-01

    Full Text Available Purpose. The development of heat treatment modes of white cast irons for structure changes in their eutectic constituent, namely in disturbing the monolithic structure of ledeburite colonies cementite structure and eutectic net continuity. Also the mentioned heat treatment modes are targeted to the eutectic net shift for the most suitable position from the point of plastic deforming. Methodology. The hypoeutectic white cast irons with 2.92…3.35 % carbon content and additionally alloyed by 3.18 % vanadium have been used as the research materials. The mentioned alloys have been pre-heat treated and hot twist tested. Findings. The research results showed that the carbide net breaking by plastic deforming leads to cast irons mechanical properties increasing but has difficulties in implementation due to the white cast irons low plasticity. The influence of different pre-heat treatment modes on structure and plasticity of white hypoeutectic cast irons have been investigated. They include the isotherm soaking under the different temperatures as well as multiply soakings and thermo-cycling. The influence of eutectic level, as well as pre heat treatment modes on different composition white cast irons hot plasticity have been investigated. Originality. It was determined that the heat treatment, which leads to double α→γ recrystallization under 860 – 950 °С and reperlitization under 720-680 °С results in significant increase of plasticity, as well as in un-alloyed and alloyed by vanadium white cast irons. It takes place due to carbide matrix phase separation in ledeburite colonies by new phase boundaries forming especially due to carbide transformations under vanadium alloying. Practical value. The implementation of pre-heat treatment with phase recrystallization resulted in hypoeutectic white cast irons plasticity increasing. The obtained level of cast iron plasticity corresponds to the one of carbide class steels, which ensures the successful

  12. 7T T₂*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease.

    Science.gov (United States)

    van Rooden, Sanneke; Doan, Nhat Trung; Versluis, Maarten J; Goos, Jeroen D C; Webb, Andrew G; Oleksik, Ania M; van der Flier, Wiesje M; Scheltens, Philip; Barkhof, Frederik; Weverling-Rynsburger, Annelies W E; Blauw, Gerard Jan; Reiber, Johan H C; van Buchem, Mark A; Milles, Julien; van der Grond, Jeroen

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T2(∗)-weighted scans were acquired in 12 EOAD patients and 17 LOAD patients with mild to moderate disease and 27 healthy elderly control subjects. Lobar peak-to-peak phase shifts and regional mean phase contrasts were computed. An increased peak-to-peak phase shift was found for all lobar regions in EOAD patients compared with LOAD patients (p < 0.05). Regional mean phase contrast in EOAD patients was higher than in LOAD patients in the superior medial and middle frontal gyrus, anterior and middle cingulate gyrus, postcentral gyrus, superior and inferior parietal gyrus, and precuneus (p ≤ 0.042). These data suggest that EOAD patients have an increased iron accumulation, possibly related to an increased amyloid deposition, in specific cortical regions as compared with LOAD patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Development of plastic elongation in nanocrystalline and amorphous Ni–W dual phase alloys by brushing technique

    International Nuclear Information System (INIS)

    Nakayama, S.; Adachi, H.; Yamasaki, T.

    2015-01-01

    Highlights: • A novel agitation technique called the brushing technique is proposed. • A homogeneous material can be obtained with the brushing technique. • The brushed material exhibits large plastic elongation with work hardening. - Abstract: A novel agitation technique, referred to as the “brushing technique” is proposed to treat the surface of a Ni–W alloy film during electrodeposition. This technique was developed to directly remove hydrogen bubbles on the film surface and to apply Ni ions to the interfacial layer with the substrate. The intrinsic mechanical properties of the Ni–W electrodeposits are then evaluated with respect to application. High resolution transmission electron microscopy observations revealed that both treated and untreated films have nanocrystallites of approximately 5 nm in diameter and an amorphous phase. There was a compositional difference of about. 1.4 at% W between the face side and the reverse side of the film that was not subjected to the brushing technique, whereas this difference was absent in the film subjected to the brushing technique. In addition, the brushing technique reduced the surface roughness of the film and decreased the number of defects. As a result, a large plastic strain of about. 2.9% was observed with work hardening under tensile testing

  14. Activation of the CREB/c-Fos Pathway during Long-Term Synaptic Plasticity in the Cerebellum Granular Layer

    Directory of Open Access Journals (Sweden)

    Daniela Gandolfi

    2017-06-01

    Full Text Available The induction of long-term potentiation and depression (LTP and LTD is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these mechanisms remained unclear. Here, we have investigated phosphorylation of the cAMP-responsive element binding protein (CREB and activation of the immediate early gene c-Fos pathway following the induction of synaptic plasticity by theta-burst stimulation (TBS in acute cerebellar slices. LTP and LTD were localized using voltage-sensitive dye imaging (VSDi. At two time points following TBS (15 min and 120 min, corresponding to the early and late phases of plasticity, slices were fixed and processed to evaluate CREB phosphorylation (P-CREB and c-FOS protein levels, as well as Creb and c-Fos mRNA expression. High levels of P-CREB and Creb/c-Fos were detected before those of c-FOS, as expected if CREB phosphorylation triggered gene expression followed by protein synthesis. No differences between control slices and slices stimulated with TBS were observed in the presence of an N-methyl-D-aspartate receptor (NMDAR antagonist. Interestingly, activation of the CREB/c-Fos system showed a relevant degree of colocalization with long-term synaptic plasticity. These results show that NMDAR-dependent plasticity at the cerebellum input stage bears about transcriptional and post-transcriptional processes potentially contributing to cerebellar learning and memory consolidation.

  15. Simulation of Dislocation and Transformation Plasticity in Shape Memory Alloys

    National Research Council Canada - National Science Library

    Volkov, Alexander

    1999-01-01

    A model of deformation of shape memory alloys has been developed. It takes into account deformation due to the phase transformation and plastic deformation, produced by an external stress or by inter-phase stresses...

  16. The highest global concentrations and increased abundance of oceanic plastic debris in the North Pacific: Evidence from seabirds

    Science.gov (United States)

    Robards, Martin D.; Gould, Patrick J.; Coe, James M.; Rogers, Donald B.

    1997-01-01

    Plastic pollution has risen dramatically with an increase in production of plastic resin during the past few decades. Plastic production in the United States increased from 2.9 million tons in I960 to 47.9 million tons in 1985 (Society of the Plastics Industry 1986). This has been paralleled by a significant increase in the concentration of plastic particles in oceanic surface waters of the North Pacific from the 1970s to the late 1980s (Day and Shaw 1987; Day et al. 1990a). Research during the past few decades has indicated two major interactions between marine life and oceanic plastic: entanglement and ingestion (Laist 1987). Studies in the last decade have documented the prevalence of plastic in the diets of many seabird species in the North Pacific and the need for further monitoring of those species and groups that ingest the most plastic (Day et al. 1985).

  17. Birefringence and incipient plastic deformation in elastically overdriven [100] CaF2 under shock compression

    Science.gov (United States)

    Li, Y.; Zhou, X. M.; Cai, Y.; Liu, C. L.; Luo, S. N.

    2018-04-01

    [100] CaF2 single crystals are shock-compressed via symmetric planar impact, and the flyer plate-target interface velocity histories are measured with a laser displacement interferometry. The shock loading is slightly above the Hugoniot elastic limit to investigate incipient plasticity and its kinetics, and its effects on optical properties and deformation inhomogeneity. Fringe patterns demonstrate different features in modulation of fringe amplitude, including birefringence and complicated modulations. The birefringence is attributed to local lattice rotation accompanying incipient plasticity. Spatially resolved measurements show inhomogeneity in deformation, birefringence, and fringe pattern evolutions, most likely caused by the inhomogeneity associated with lattice rotation and dislocation slip. Transiently overdriven elastic states are observed, and the incubation time for incipient plasticity decreases inversely with increasing overdrive by the elastic shock.

  18. 19 CFR 148.4 - Accompanying articles.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Accompanying articles. 148.4 Section 148.4 Customs... (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS General Provisions § 148.4 Accompanying articles. (a) Generally. Articles shall be considered as accompanying a passenger or brought in by him if the articles...

  19. Plastics and environmental health: the road ahead.

    Science.gov (United States)

    North, Emily J; Halden, Rolf U

    2013-01-01

    Plastics continue to benefit society in innumerable ways, even though recent public focus on plastics has centered mostly on human health and environmental concerns, including their endocrine-disrupting properties and the long-term pollution they represent. The benefits of plastics are particularly apparent in medicine and public health. Plastics are versatile, cost-effective, require less energy to produce than alternative materials like metal or glass, and can be manufactured to have many different properties. Due to these characteristics, polymers are used in diverse health applications like disposable syringes and intravenous bags, sterile packaging for medical instruments as well as in joint replacements, tissue engineering, etc. However, not all current uses of plastics are prudent and sustainable, as illustrated by the widespread, unwanted human exposure to endocrine-disrupting bisphenol A (BPA) and di-(2-ethylhexyl)phthalate (DEHP), problems arising from the large quantities of plastic being disposed of, and depletion of non-renewable petroleum resources as a result of the ever-increasing mass production of plastic consumer articles. Using the health-care sector as example, this review concentrates on the benefits and downsides of plastics and identifies opportunities to change the composition and disposal practices of these invaluable polymers for a more sustainable future consumption. It highlights ongoing efforts to phase out DEHP and BPA in the health-care and food industry and discusses biodegradable options for plastic packaging, opportunities for reducing plastic medical waste, and recycling in medical facilities in the quest to reap a maximum of benefits from polymers without compromising human health or the environment in the process.

  20. Plastics and Environmental Health: The Road Ahead

    Science.gov (United States)

    North, Emily J.; Halden, Rolf U.

    2013-01-01

    Plastics continue to benefit society in innumerable ways, even though recent public focus on plastics has centered mostly on human health and environmental concerns, including endocrine-disrupting properties and long-term pollution. The benefits of plastics are particularly apparent in medicine and public health. Plastics are versatile, cost-effective, require less energy to produce than alternative materials – such as metal or glass – and can be manufactured to have many different properties. Due to these characteristics, polymers are used in diverse health applications, such as disposable syringes and intravenous bags, sterile packaging for medical instruments as well as in joint replacements, tissue engineering, etc. However, not all current uses of plastics are prudent and sustainable, as illustrated by widespread, unwanted human exposure to endocrine-disrupting bisphenol-A (BPA) and di-(2-ethylhexyl)phthalate (DEHP), problems arising from the large quantities of plastic being disposed of, and depletion of non-renewable petroleum resources as a result of ever increasing mass-production of plastic consumer articles. By example of the healthcare sector, this review concentrates on benefits and downsides of plastics and identities opportunities to change the composition and disposal practices of these invaluable polymers for a more sustainable future consumption. It highlights ongoing efforts to phase out DEHP and BPA in the healthcare and food industry, and discusses biodegradable options for plastic packaging, opportunities for reducing plastic medical waste, and recycling in medical facilities in the quest to reap a maximum of benefits from polymers without compromising human health or the environment in the process. PMID:23337043

  1. Solid phase radioimmunoassays

    International Nuclear Information System (INIS)

    Wide, L.

    1977-01-01

    Solid phase coupled antibodies were introduced to facilitate the separation of bound and free labelled ligand in the competitive inhibition radioimmunoassay. Originally, the solid matrix used was in the form of small particles and since then a number of different matrices have been used such as very fine powder particles, gels, paper and plastic discs, magnetic particles and the inside surface of plastic tubes. The coupling of antibodies may be that of a covalent chemical binding, a strong physical adsorbtion, or an immunological binding to a solid phase coupled antigen. New principles of radioimmunoassay such as the solid phase sandwich techniques and the immunoradiometric assay were developped from the use of solid phase coupled antigens and antibodies. The solid phase sandwich techniques are reagent excess methods with a very wide applicability. Several of the different variants of solid phase techniques are suitable for automation. Advantages and disadvantages of solid phase radioimmunoassays when compared with those using soluble reagents are discussed. (orig.) [de

  2. Constitutive model of discontinuous plastic flow at cryogenic temperatures

    CERN Document Server

    Skoczen, B; Bielski, J; Marcinek, D

    2010-01-01

    FCC metals and alloys are frequently used in cryogenic applications, nearly down to the temperature of absolute zero, because of their excellent physical and mechanical properties including ductility. Some of these materials, often characterized by the low stacking fault energy (LSFE), undergo at low temperatures three distinct phenomena: dynamic strain ageing (DSA), plastic strain induced transformation from the parent phase (gamma) to the secondary phase (alpha) and evolution of micro-damage. The constitutive model presented in the paper is focused on the discontinuous plastic flow (serrated yielding) and takes into account the relevant thermodynamic background. The discontinuous plastic flow reflecting the DSA effect is described by the mechanism of local catastrophic failure of Lomer-Cottrell (LC) locks under the stress fields related to the accumulating edge dislocations (below the transition temperature from the screw dislocations to the edge dislocations mode T-1). The failure of LC locks leads to mass...

  3. Developmental plasticity of growth and digestive efficiency in dependence of early-life food availability

    Science.gov (United States)

    Kotrschal, Alexander; Szidat, Sönke; Taborsky, Barbara

    2014-01-01

    Nutrition is a potent mediator of developmental plasticity. If food is scarce, developing organisms may invest into growth to outgrow size-dependent mortality (short-term benefit) and/or into an efficient digestion system (long-term benefit). We investigated this potential trade-off, by determining the influence of food availability on juvenile body and organ growth, and on adult digestive efficiency in the cichlid fish Simochromis pleurospilus. We reared two groups of fish at constant high or low food rations, and we switched four other groups between these two rations at an early and late juvenile period. We measured juvenile growth and organ sizes at different developmental stages and determined adult digestive efficiency. Fish kept at constant, high rations grew considerably faster than low-food fish. Nevertheless, S. pleurospilus partly buffered the negative effects of low food availability by developing heavier digestive organs, and they were therefore more efficient in digesting their food as adults. Results of fish exposed to a ration switch during either the early or late juvenile period suggest (i) that the ability to show compensatory growth after early exposure to low food availability persists during the juvenile period, (ii) that digestive efficiency is influenced by varying juvenile food availability during the late juvenile phase and (iii) that the efficiency of the adult digestive system is correlated with the growth rate during a narrow time window of juvenile period. PMID:25866430

  4. Spinal Plasticity and Behavior: BDNF-Induced Neuromodulation in Uninjured and Injured Spinal Cord

    Science.gov (United States)

    Huie, J. Russell

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophic factor family of signaling molecules. Since its discovery over three decades ago, BDNF has been identified as an important regulator of neuronal development, synaptic transmission, and cellular and synaptic plasticity and has been shown to function in the formation and maintenance of certain forms of memory. Neural plasticity that underlies learning and memory in the hippocampus shares distinct characteristics with spinal cord nociceptive plasticity. Research examining the role BDNF plays in spinal nociception and pain overwhelmingly suggests that BDNF promotes pronociceptive effects. BDNF induces synaptic facilitation and engages central sensitization-like mechanisms. Also, peripheral injury-induced neuropathic pain is often accompanied with increased spinal expression of BDNF. Research has extended to examine how spinal cord injury (SCI) influences BDNF plasticity and the effects BDNF has on sensory and motor functions after SCI. Functional recovery and adaptive plasticity after SCI are typically associated with upregulation of BDNF. Although neuropathic pain is a common consequence of SCI, the relation between BDNF and pain after SCI remains elusive. This article reviews recent literature and discusses the diverse actions of BDNF. We also highlight similarities and differences in BDNF-induced nociceptive plasticity in naïve and SCI conditions. PMID:27721996

  5. Spinal Plasticity and Behavior: BDNF-Induced Neuromodulation in Uninjured and Injured Spinal Cord

    Directory of Open Access Journals (Sweden)

    Sandra M. Garraway

    2016-01-01

    Full Text Available Brain-derived neurotrophic factor (BDNF is a member of the neurotrophic factor family of signaling molecules. Since its discovery over three decades ago, BDNF has been identified as an important regulator of neuronal development, synaptic transmission, and cellular and synaptic plasticity and has been shown to function in the formation and maintenance of certain forms of memory. Neural plasticity that underlies learning and memory in the hippocampus shares distinct characteristics with spinal cord nociceptive plasticity. Research examining the role BDNF plays in spinal nociception and pain overwhelmingly suggests that BDNF promotes pronociceptive effects. BDNF induces synaptic facilitation and engages central sensitization-like mechanisms. Also, peripheral injury-induced neuropathic pain is often accompanied with increased spinal expression of BDNF. Research has extended to examine how spinal cord injury (SCI influences BDNF plasticity and the effects BDNF has on sensory and motor functions after SCI. Functional recovery and adaptive plasticity after SCI are typically associated with upregulation of BDNF. Although neuropathic pain is a common consequence of SCI, the relation between BDNF and pain after SCI remains elusive. This article reviews recent literature and discusses the diverse actions of BDNF. We also highlight similarities and differences in BDNF-induced nociceptive plasticity in naïve and SCI conditions.

  6. Plasticity of decagonal Al-Ni-Co single quasicrystals

    International Nuclear Information System (INIS)

    Schall, P.

    2002-03-01

    Decagonal quasicrystals exhibit quasiperiodic order along two spatial directions and periodic order along the third. Many physical properties of these materials show an anisotropic behaviour. Three different modifications of the decagonal phase in the Al-Ni-Co system were grown as single crystals using the Bridgman and flux growth techniques: quasicrystals of a nickel-rich composition, the so-called basic Ni phase, of a composition of about Al 70 Ni 15 Co 15 and of a cobalt-rich composition, so-called basic Co. Plastic deformation experiments at constant strain rate were carried out on these phases at temperatures of about 70 to 85% of the melting temperature. Stress-relaxation tests and temperature changes were performed during the deformation to study the strain-rate and temperature sensitivity of the flow stress, respectively. Distinct anisotropies are observed in the plastic behaviour, which differ fundamentally for the three modifications. Microstructural investigations of deformed samples by transmission electron microscopy show that plastic deformation is mediated by a dislocation mechanism. Depending on orientation a pure glide, a pure climb or a mixed glide and climb process is observed. Burgers vectors were determined by convergent beam electron diffraction in direction and length. Three different types of dislocations are observed, i.e. dislocations with a periodic, quasiperiodic and a mixed Burgers vector. The Burgers vectors were identified in a current structure model. The dislocations with the periodic and the mixed Burgers vector exhibit reactions which are of fundamental importance for the macroscopic deformation behaviour. In particular, they explain the different plastic behaviours of the three modifications. (orig.)

  7. [Disturbed respiratory cycle accompanying hypoxic-ischemic encephalopathy].

    Science.gov (United States)

    Saito, Yoshiaki; Masuko, Kaori; Kaneko, Kaori; Saito, Kazuyo; Chikumaru, Yuri; Iwamoto, Hiroko; Matsui, Akira; Kimura, Seiji

    2005-09-01

    We report the case of a 2-year-old boy who experienced total asphyxia at 4 months of age, and suffered abnormalities at specific phases of the respiratory cycle. The patient was bedridden due to severe tetraplegia and showed little response to external stimuli. He has been tube-fed since the initial asphyxia and a tracheotomy was performed after recurrent hypoxic episodes as a result of the respiratory dysfunction. Upon examination, his respiratory pattern was characterized by arrest during the inspiratory phase with a possible over-riding secondary inspiration. The respiratory pause at the inspiratory phase was markedly prolonged during an episode of pulmonary infection, resulting in recurrent cyanosis that necessitated artificial ventilation. The "second" inspiration typically occurred during the mid- or late-inspiratory phases, with this pattern often shown to be variable after epileptic seizures. The characteristic breathing of this patient suggested that difficulty in forming a normal respiratory cycle, other than during periods of hypoventilation or apnoea, could be a significant respiratory dysfunction following asphyxiation. Strategies for the management of such patients should be carefully designed after close observation of breathing patterns within the respiratory cycle, and with consideration for the influence of epileptic seizures and other inputs from somatic afferents.

  8. Microcellular foams via phase separation

    International Nuclear Information System (INIS)

    Young, A.T.

    1985-01-01

    A study of wide variety of processes for making plastic foams shows that phase separation processes for polymers from solutions offers the most viable methods for obtaining rigid plastic foams which met the physical requirements for fusion target designs. Four general phase separation methods have been shown to give polymer foams with densities less than 0.1 g/cm 3 and cell sizes of 30μm or less. These methods involve the utilization of non-solvent, chemical or thermal cooling processes to achieve a controlled phase separation wherein either two distinct phases are obtained where the polymer phase is a continuous phase or two bicontinuous phases are obtained where both the polymer and solvent are interpenetrating, continuous, labyrinthine phases. Subsequent removal of the solvent gives the final foam structure

  9. Boron content effect on the high-temperature plasticity of corrosion resistant low-carbon austenite type steels

    International Nuclear Information System (INIS)

    Gol'dshtejn, Ya.E.; Shmatko, M.N.; Chuvatina, S.N.

    1976-01-01

    With the concept that the state of grain and subgrain boundaries influences the hot plasticity of corrosion resistant steel as a starting point, the study was undertaken of the effect of boron microalloying up on the intergranular strength and of the action boron exerts upon the distribution (redistribution) of other phases present in austenitic 03Kh16N14M3 steels. An electron microscope study of the composition of redundant phases and that of the fine structure of steel have shown the effect of small additions of boron upon the hot plasticity of steel to be linked directly to its influence upon austenite disintegration and the precipitation along the boundaries of crystals of redundant phases in the course of hot plastic deformation. The action of boron upon the process plasticity of steel depends on the temperature and the rate of deformation which govern the kinetics of the precipitation of the redundant phases

  10. Resistance to small plastic strains during martensite tempering under tension

    Energy Technology Data Exchange (ETDEWEB)

    Zabil' skij, V.V.; Sarrak, V.I. (AN SSSR, Sverdlovsk. Inst. Fiziki Metallov)

    1982-11-01

    The mechanism of plastic deformation of martensite of a series of hardened steels (N18, 20KhG, 50KhFA and others) during tempering under tension and the role of residual internal microstresses and phase transformations are studied. It is shown that martensite low resistance to small plastic deformations during tempering under tension which is usually associated with phase transformations depends as well on the level of residual internal microstresses in the martensite structure. The decrease of resistance to deformation in the course of the decomposition of a solid solution is due to weakening of martensitic matrix because of carbon departure from the solid solution and carbide coarsening. An assumption is made that martensite plastic deformation during tempering under tension is realized at the expense of the directed microplastic deformation in the regions of higher concentration of internal stresses.

  11. The differences in RCAS1 and DFF45 endometrial expression between late proliferative, early secretory, and mid-secretory cycle phases.

    Directory of Open Access Journals (Sweden)

    Jerzy Sikora

    2008-04-01

    Full Text Available RCAS1 expression is related to the regulation of activated immune cells and to connective tissue remodeling within the endometrium. DFF45 seems to play an important role in the apoptotic process, most likely by acting through the regulation of DNA fragmentation. Its expression changes within the endometrium seem to be related to the resistance of endometrial cells to apoptosis. The aim of the present study was to evaluate RCAS1 and DFF45 endometrial expressions during ovulation and the implantation period. RCAS1 and DFF45 expression was assessed by the Western-blot method in endometrial tissue samples obtained from 20 patients. The tissue samples were classified according to the menstrual cycle phases in which they were collected, with a division into three phases: late proliferative, early secretory, and mid-secretory. The lowest level of RCAS1 and the highest level of DFF45 endometrial expression was found during the early secretory cycle phase. Statistically significantly higher RCAS1 and statistically significantly lower DFF45 endometrial expression was identified in the endometrium during the late proliferative as compared to the early secretory cycle phase. Moreover, statistically significantly higher RCAS1 and statistically significantly lower DFF45 expression was found in the endometrium during the mid-secretory as compared to the early secretory cycle phase. The preparation for implantation process in the endometrium is preceded by dynamic changes in endometrial ECM and results from the proper interaction between endometrial and immune cells. The course of this process is conditioned by the immunomodulating activity of endometrial cells and their resistance to immune-mediated apoptosis. These dynamic changes are closely related to RCAS1 and DFF45 expression alterations.

  12. Differential involvement of IL-6 in the early and late phase of 1-methylnicotinamide (MNA) release in Concanavalin A-induced hepatitis.

    Science.gov (United States)

    Sternak, Magdalena; Jakubowski, Andrzej; Czarnowska, Elzbieta; Slominska, Ewa M; Smolenski, Ryszard T; Szafarz, Malgorzata; Walczak, Maria; Sitek, Barbara; Wojcik, Tomasz; Jasztal, Agnieszka; Kaminski, Karol; Chlopicki, Stefan

    2015-09-01

    Exogenous 1-methylnicotinamide (MNA) displays anti-inflammatory activity. The aim of this work was to characterize the profile of release of endogenous MNA during the initiation and progression of murine hepatitis induced by Concanavalin A (ConA). In particular we aimed to clarify the role of interleukin-6 (IL-6) as well as the energy state of hepatocytes in MNA release in early and late phases of ConA-induced hepatitis in mice. Hepatitis was induced by ConA in IL-6(+/+) and IL-6(-/-) mice, and various parameters of liver inflammation and injury, as well as the energy state of hepatocytes, were analysed in relation to MNA release. The decrease in ATP/ADP and NADH/NAD ratios, cytokine release (IL-6, IFN-ɤ), acute phase response (e.g. haptoglobin) and liver injury (alanine aminotransaminase, ALT) were all blunted in ConA-induced hepatitis in IL-6(-/-) mice as compared to IL-6(+/+) mice. The release of MNA in response to Con A was also significantly blunted in IL-6(-/-) mice as compared to IL-6(+/+) mice in the early stage of ConA-induced hepatitis. In turn, nicotinamide N-methyltransferase (NNMT) and aldehyde oxidase (AO) activities were blunted in the liver and MNA plasma concentration was elevated to similar degree in the late stage after Concanavalin A in IL-6(+/+) and IL-6(-/-) mice. In conclusion, we demonstrated that in ConA-induced hepatitis, early, but not late MNA release was IL-6-dependent. Our results suggest that in the initiation and early hepatitis, MNA release is linked to the energy deficit/impaired redox status in hepatocytes, while in a later phase, MNA release is rather linked to the systemic inflammation. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Late Paleogene reticulate Nummulites of the Western Tethys

    Science.gov (United States)

    Less, G.; Kertész, B.; Özcan, E.

    2012-04-01

    Reticulate Nummulites can be found very often in rock-forming quantity in the Bartonian to lower Chattian beds of the Western Tethys; however their nomenclature is extremely complicated and rather controversial. Therefore, and since B-forms are quite rare and often missing, in the first phase of the research we have concentrated on the comparative morphometric study of megalospheric forms without prejudicing formerly introduced typological names to particular populations. We used material from fourty-six localities extending from SW France to Cutch (W India) and spanning from the early Bartonian to the early Chattian. Fifty-six populations could be encountered, fifty-five of which could be arranged safely into the well-known Nummulites fabianii-fichteli group. However, in the middle Bartonian locality of Keçili 1 (eastern Turkey) another population of reticulate Nummulites bearing about five times larger embryon than that of the population belonging to the N. fabianii-fichteli-lineage from the same sample could be observed. This population has been identified with N. hottingeri (the end-member of the N. partschi-lorioli-lineage) on the one hand but also with the original description of N. ptukhiani (later widely accepted as the precursor of N. fabianii) on the other. This means that the two names are synonymous and N. ptukhiani bearing priority advantage over N. hottingeri has to be applied for these forms. On the other hand, it can by no means be used for the precursor forms of N. fabianii. The fifly-five populations belonging to the Nummulites fabianii-fichteli group have been analyzed qualitatively by means of the surface characteristics and quantitatively by means of the internal features observable in the equatorial section of A-forms. In order to distinguish the evolutionary trends from the ecologically or ontogenetically induced phenomena we arranged these populations according to their supposed ages based on the accompanying fossils and/or stratigraphical

  14. Shaping inhibition: activity dependent structural plasticity of GABAergic synapses

    Directory of Open Access Journals (Sweden)

    Carmen E Flores

    2014-10-01

    Full Text Available Inhibitory transmission through the neurotransmitter Ɣ-aminobutyric acid (GABA shapes network activity in the mammalian cerebral cortex by filtering synaptic incoming information and dictating the activity of principal cells. The incredibly diverse population of cortical neurons that use GABA as neurotransmitter shows an equally diverse range of mechanisms that regulate changes in the strength of GABAergic synaptic transmission and allow them to dynamically follow and command the activity of neuronal ensembles. Similarly to glutamatergic synaptic transmission, activity-dependent functional changes in inhibitory neurotransmission are accompanied by alterations in GABAergic synapse structure that range from morphological reorganization of postsynaptic density to de novo formation and elimination of inhibitory contacts. Here we review several aspects of structural plasticity of inhibitory synapses, including its induction by different forms of neuronal activity, behavioral and sensory experience and the molecular mechanisms and signaling pathways involved. We discuss the functional consequences of GABAergic synapse structural plasticity for information processing and memory formation in view of the heterogenous nature of the structural plasticity phenomena affecting inhibitory synapses impinging on somatic and dendritic compartments of cortical and hippocampal neurons.

  15. Cancer Stem Cell Plasticity as Tumor Growth Promoter and Catalyst of Population Collapse

    Directory of Open Access Journals (Sweden)

    Jan Poleszczuk

    2016-01-01

    Full Text Available It is increasingly argued that cancer stem cells are not a cellular phenotype but rather a transient state that cells can acquire, either through intrinsic signaling cascades or in response to environmental cues. While cancer stem cell plasticity is generally associated with increased aggressiveness and treatment resistance, we set out to thoroughly investigate the impact of different rates of plasticity on early and late tumor growth dynamics and the response to therapy. We develop an agent-based model of cancer stem cell driven tumor growth, in which plasticity is defined as a spontaneous transition between stem and nonstem cancer cell states. Simulations of the model show that plasticity can substantially increase tumor growth rate and invasion. At high rates of plasticity, however, the cells get exhausted and the tumor will undergo spontaneous remission in the long term. In a series of in silico trials, we show that such remission can be facilitated through radiotherapy. The presented study suggests that stem cell plasticity has rather complex, nonintuitive implications on tumor growth and treatment response. Further theoretical, experimental, and integrated studies are needed to fully decipher cancer stem cell plasticity and how it can be harnessed for novel therapeutic approaches.

  16. Psychedelics Promote Structural and Functional Neural Plasticity

    Directory of Open Access Journals (Sweden)

    Calvin Ly

    2018-06-01

    Full Text Available Summary: Atrophy of neurons in the prefrontal cortex (PFC plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders. : Ly et al. demonstrate that psychedelic compounds such as LSD, DMT, and DOI increase dendritic arbor complexity, promote dendritic spine growth, and stimulate synapse formation. These cellular effects are similar to those produced by the fast-acting antidepressant ketamine and highlight the potential of psychedelics for treating depression and related disorders. Keywords: neural plasticity, psychedelic, spinogenesis, synaptogenesis, depression, LSD, DMT, ketamine, noribogaine, MDMA

  17. Psychedelics Promote Structural and Functional Neural Plasticity.

    Science.gov (United States)

    Ly, Calvin; Greb, Alexandra C; Cameron, Lindsay P; Wong, Jonathan M; Barragan, Eden V; Wilson, Paige C; Burbach, Kyle F; Soltanzadeh Zarandi, Sina; Sood, Alexander; Paddy, Michael R; Duim, Whitney C; Dennis, Megan Y; McAllister, A Kimberley; Ori-McKenney, Kassandra M; Gray, John A; Olson, David E

    2018-06-12

    Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in vitro and in vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  18. Pyrolysis of fibre residues with plastic contamination from a paper recycling mill: Energy recoveries

    International Nuclear Information System (INIS)

    Brown, Logan Jeremy; Collard, François-Xavier; Görgens, Johann

    2017-01-01

    Highlights: • Pyrolysis of fibre-plastics residues from paper recycling mill into fuel products. • Product with remarkable energy content up to 42.8 MJ/kg. • Influence of temperature on the product yields and fuel properties. • Effect of plastic composition on product properties. - Abstract: Pyrolysis is a promising technology for the production of marketable energy products from waste mixtures, as it decomposes heterogeneous material into homogenous fuel products. This research assessed the ability of slow pyrolysis to convert three waste streams, composed of fibre residues contaminated with different plastic mixtures, into char and tarry phase products at three different temperatures (300, 425 and 550 °C). The products were characterised in terms of mass yield, higher heating value (HHV) and gross energy conversion (EC). Significant amounts of hydrocarbon plastics in the feed materials increased the calorific values of the char (up to 32.9 MJ/kg) and tarry phase (up to 42.8 MJ/kg) products, comparable to high volatile bituminous A coal and diesel respectively. For all three waste streams converted at 300 °C, the majority of the energy in the feedstock was recovered in the char product (>80%), while deoxygenation of fibre component resulted in char with increased calorific value (up to 31.6 MJ/kg) being produced. Pyrolysis at 425 °C for two of the waste streams containing significant amounts of plastic produced both a valuable char and tarry phase, which resulted in an EC greater than 74%. Full conversion of plastic at 550 °C increased the tarry phase yield but dramatically decreased the char HHV. The influence of temperature on product yield and HHV was discussed based on the pyrolysis mechanisms and in relation to the plastic composition of the waste streams.

  19. Extracellular proteolysis in structural and functional plasticity of mossy fiber synapses in hippocampus

    Directory of Open Access Journals (Sweden)

    Grzegorz eWiera

    2015-11-01

    Full Text Available Brain is continuously altered in response to experience and environmental changes. One of the underlying mechanisms is synaptic plasticity, which is manifested by modification of synapse structure and function. It is becoming clear that regulated extracellular proteolysis plays a pivotal role in the structural and functional remodeling of synapses during brain development, learning and memory formation. Clearly, plasticity mechanisms may substantially differ between projections. Mossy fiber synapses onto CA3 pyramidal cells display several unique functional features, including pronounced short-term facilitation, a presynaptically expressed LTP that is independent of NMDAR activation, and NMDA-dependent metaplasticity. Moreover, structural plasticity at mossy fiber synapses ranges from the reorganization of projection topology after hippocampus-dependent learning, through intrinsically different dynamic properties of synaptic boutons to pre- and postsynaptic structural changes accompanying LTP induction. Although concomitant functional and structural plasticity in this pathway strongly suggests a role of extracellular proteolysis, its impact only starts to be investigated in this projection. In the present report, we review the role of extracellular proteolysis in various aspects of synaptic plasticity in hippocampal mossy fiber synapses. A growing body of evidence demonstrates that among perisynaptic proteases, tPA/plasmin system, β-site amyloid precursor protein-cleaving enzyme 1 (BACE1 and metalloproteinases play a crucial role in shaping plastic changes in this projection. We discuss recent advances and emerging hypotheses on the roles of proteases in mechanisms underlying mossy fiber target specific synaptic plasticity and memory formation.

  20. Calculation of recovery plasticity in multistage hot forging under isothermal conditions.

    Science.gov (United States)

    Zhbankov, Iaroslav G; Perig, Alexander V; Aliieva, Leila I

    2016-01-01

    A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet under isothermal conditions is proposed. This method allows the prediction of billet forming limits as a function of deformation during the forging stage and the duration of the pause between the stages. This method takes into account the duration of pauses between deformations and the magnitude of subdivided deformations. A hot isothermal upsetting process with pauses was calculated by the proposed method. Results of the calculations have been confirmed with experimental data.

  1. Experimental study of discontinuous plastic flow, phase transformation and micro-damage evolution in ductile materials at cryogenic temperatures

    CERN Document Server

    Marcinek, Dawid Jarosław; Sgobba, S

    2009-01-01

    The present Thesis deals with three low temperature phenomena occurring in ductile materials subjected to mechanical loads: serrated yielding, plastic strain induced γ-α’ phase transformation and evolution of micro-damage: - the Thesis explains the physical mechanisms governing each phenomenon at the micro and macroscopic levels; - the document describes in detail the advanced laboratory equipment needed for cryogenic experiments; - the results of tests carried out with unique precision and focused on serrated yielding and evolution of micro-damage (the observations were made with different strain rates and with the use of different materials) are presented; - validation of suitable kinetic laws and identification of parameters for tested materials is carried out.

  2. Persistent deficits in hippocampal synaptic plasticity accompany losses of hippocampus-dependent memory in a rodent model of psychosis

    Directory of Open Access Journals (Sweden)

    Valentina eWiescholleck

    2013-03-01

    Full Text Available Irreversible N-methyl-D-aspartate receptor (NMDAR antagonism is known to provoke symptoms of psychosis and schizophrenia in healthy humans. NMDAR hypofunction is believed to play a central role in the pathophysiology of both disorders and in an animal model of psychosis, that is based on irreversible antagonism of NMDARs, pronounced deficits in hippocampal synaptic plasticity have been reported shortly after antagonist treatment. Here, we examined the long-term consequences for long-term potentiation (LTP of a single acute treatment with an irreversible antagonist and investigated whether deficits are associated with memory impairments.The ability to express long-term potentiation (LTP at the perforant pathway – dentate gyrus synapse, as well as object recognition memory was assessed 1, 2, 3 and 4 weeks after a single -treatment of the antagonist, MK801. Here, LTP in freely behaving rats was significantly impaired at all time-points compared to control LTP before treatment. Object recognition memory was also significantly poorer in MK801-treated compared to vehicle-treated animals for several weeks after treatment. Histological analysis revealed no changes in brain tissue.Taken together, these data support that acute treatment with an irreversible NMDAR antagonist persistently impairs hippocampal functioning on behavioral, as well as synaptic levels. The long-term deficits in synaptic plasticity may underlie the cognitive impairments that are associated with schizophrenia-spectrum disorders.

  3. Plastic solidification system for radioactive waste

    International Nuclear Information System (INIS)

    Kani, Jiro; Irie, Hiromitsu; Obu, Etsuji; Nakayama, Yasuyuki; Matsuura, Hiroyuki.

    1979-01-01

    The establishment of a new solidification system is an important theme for recent radioactive-waste disposal systems. The conditions required of new systems are: (1) the volume of the solidified product to be reduced, and (2) the property of the solidified product to be superior to the conventional ones. In the plastic solidification system developed by Toshiba, the waste is first dried and then solidified with thermosetting resin. It has been confirmed that the property of the plastic solidified product is superior to that of the cement-or bitumen-solidified product. Investigation from various phases is being carried on for the application of this method to commercial plants. (author)

  4. Early and late allergic reaction in the nose assessed by whole body plethysmography

    NARCIS (Netherlands)

    deBruinWeller, MS; Weller, FR; Scholte, A; Rijssenbeek, LHM; vanderBaan, S; Bogaard, JM; deMonchy, JGR

    Physiological changes during late phase nasal responses after allergen challenge are difficult to establish and different criteria are used for the definition of a positive late phase nasal reaction. The objective of this study was to assess the value of whole body plethysmography in detecting

  5. Early and late allergic reaction in the nose assessed by whole body plethysmography

    NARCIS (Netherlands)

    de Bruin-Weller, M. S.; Weller, F. R.; Scholte, A.; Rijssenbeek, L. H.; van der Baan, S.; Bogaard, J. M.; de Monchy, J. G.

    1996-01-01

    Physiological changes during late phase nasal responses after allergen challenge are difficult to establish and different criteria are used for the definition of a positive late phase nasal reaction. The objective of this study was to assess the value of whole body plethysmography in detecting

  6. Bridging the Faraoni and Selli oceanic anoxic events: late Hauterivian to early Aptian dysaerobic to anaerobic phases in the Tethys

    Science.gov (United States)

    Föllmi, K. B.; Bôle, M.; Jammet, N.; Froidevaux, P.; Godet, A.; Bodin, S.; Adatte, T.; Matera, V.; Fleitmann, D.; Spangenberg, J. E.

    2012-01-01

    following return to more oxygenated conditions is correlated with the second phase of Urgonian platform growth and the period immediately preceding and corresponding to the Selli anoxic episode is characterised by renewed platform drowning and the change to heterozoan carbonate production. Changes towards more humid climate conditions were the likely cause for the repetitive installation of dys- to anaerobic conditions in the Tethyan and Boreal basins and the accompanying changes in the evolution of the carbonate platform towards heterozoan carbonate-producing ecosystems and platform drowning.

  7. Bridging the Faraoni and Selli oceanic anoxic events: late Hauterivian to early Aptian dysaerobic to anaerobic phases in the Tethys

    Directory of Open Access Journals (Sweden)

    K. B. Föllmi

    2012-01-01

    production on the northern Tethyan shelf. The following return to more oxygenated conditions is correlated with the second phase of Urgonian platform growth and the period immediately preceding and corresponding to the Selli anoxic episode is characterised by renewed platform drowning and the change to heterozoan carbonate production. Changes towards more humid climate conditions were the likely cause for the repetitive installation of dys- to anaerobic conditions in the Tethyan and Boreal basins and the accompanying changes in the evolution of the carbonate platform towards heterozoan carbonate-producing ecosystems and platform drowning.

  8. Cannabinoids ameliorate impairments induced by chronic stress to synaptic plasticity and short-term memory.

    Science.gov (United States)

    Abush, Hila; Akirav, Irit

    2013-07-01

    Repeated stress is one of the environmental factors that precipitates and exacerbates mental illnesses like depression and anxiety as well as cognitive impairments. We have previously shown that cannabinoids can prevent the effects of acute stress on learning and memory. Here we aimed to find whether chronic cannabinoid treatment would alleviate the long-term effects of exposure to chronic restraint stress on memory and plasticity as well as on behavioral and neuroendocrine measures of anxiety and depression. Late adolescent rats were exposed to chronic restraint stress for 2 weeks followed each day by systemic treatment with vehicle or with the CB1/2 receptor agonist WIN55,212-2 (1.2 mg/kg). Thirty days after the last exposure to stress, rats demonstrated impaired long-term potentiation (LTP) in the ventral subiculum-nucleus accumbens (NAc) pathway, impaired performance in the prefrontal cortex (PFC)-dependent object-recognition task and the hippocampal-dependent spatial version of this task, increased anxiety levels, and significantly reduced expression of glucocorticoid receptors (GRs) in the amygdala, hippocampus, PFC, and NAc. Chronic WIN55,212-2 administration prevented the stress-induced impairment in LTP levels and in the spatial task, with no effect on stress-induced alterations in unconditioned anxiety levels or GR levels. The CB1 antagonist AM251 (0.3 mg/kg) prevented the ameliorating effects of WIN55,212-2 on LTP and short-term memory. Hence, the beneficial effects of WIN55,212-2 on memory and plasticity are mediated by CB1 receptors and are not mediated by alterations in GR levels in the brain areas tested. Our findings suggest that cannabinoid receptor activation could represent a novel approach to the treatment of cognitive deficits that accompany a variety of stress-related neuropsychiatric disorders.

  9. [Remote results of plastic operations on the tricuspid valve in patients with cardiac insufficiency at terminal stage].

    Science.gov (United States)

    Habriielian, A V; Smorzhevs'kyĭ, V I; Onishchenko, V F; Beleĭovych, V V; Topchu, Ie I; Domans'kyĭ, T M; Myroniuk, O I

    2011-07-01

    Comparative analysis of the results of plastic operations performance on a tricuspid valve (TV) in patients, suffering cardiac insufficiency in terminal stage, was conducted. In late postoperative period the indices of intracardial hemodynamics (cardiac output fraction, regurgitation on TV) and clinical features (severity of symptoms, quality of life) after plastic operations, using a support ring, have differed significantly from those after performance of a sutured plasty. The valve function during five years was secured in 91.1% of patients.

  10. Bidirectional plasticity of pontine pneumotaxic postinspiratory drive: implication for a pontomedullary respiratory central pattern generator.

    Science.gov (United States)

    Poon, Chi-Sang; Song, Gang

    2014-01-01

    The "pneumotaxic center" in the rostral dorsolateral pons as delineated by Lumsden nine decades ago is known to play an important role in promoting the inspiratory off-switch (IOS) for inspiratory-expiratory phase transition as a fail-safe mechanism for preventing apneusis in the absence of vagal input. Traditionally, the pontine pneumotaxic mechanism has been thought to contribute a tonic descending input that lowers the IOS threshold in medullary respiratory central pattern generator (rCPG) circuits, but otherwise does not constitute part of the rCPG. Recent evidence indicates that descending input from the Kölliker-Fuse nucleus (KFN) within the pneumotaxic center is essential for gating the postinspiratory phase of the three-phase respiratory rhythm to control the IOS in vagotomized animals. A critical question arising is whether such a descending pneumotaxic input from KFN that drives postinspiratory activity is tonic (null hypothesis) or rhythmic with postinspiratory phase modulation (alternative hypothesis). Here, we show that multifarious evidence reported in the literature collectively indicates that the descending pneumotaxic input may exhibit NMDA receptor-dependent short-term plasticity in the form of a biphasic neural differentiator that bidirectionally and phase-selectively modulates postinspiratory phase duration in response to vagal and peripheral chemoreceptor inputs independent of the responses in inspiratory and late-expiratory activities. The phase-selectivity property of the descending pneumotaxic input implicates a population of pontine early-expiratory (postinspiratory/expiratory-decrementing) neurons as the most likely neural correlate of the pneumotaxic mechanism that drives post-I activity, suggesting that the pontine pneumotaxic mechanism may be an integral part of a pontomedullary rCPG that underlies the three-phase respiratory rhythm. © 2014 Elsevier B.V. All rights reserved.

  11. Key Metabolic Enzymes Underlying Astrocytic Upregulation of GABAergic Plasticity

    Directory of Open Access Journals (Sweden)

    Przemysław T. Kaczor

    2017-05-01

    Full Text Available GABAergic plasticity is recognized as a key mechanism of shaping the activity of the neuronal networks. However, its description is challenging because of numerous neuron-specific mechanisms. In particular, while essential role of glial cells in the excitatory plasticity is well established, their involvement in GABAergic plasticity only starts to emerge. To address this problem, we used two models: neuronal cell culture (NC and astrocyte-neuronal co-culture (ANCC, where we chemically induced long-term potentiation at inhibitory synapses (iLTP. iLTP could be induced both in NC and ANCC but in ANCC its extent was larger. Importantly, this functional iLTP manifestation was accompanied by an increase in gephyrin puncta size. Furthermore, blocking astrocyte Krebs cycle with fluoroacetate (FA in ANCC prevented enhancement of both mIPSC amplitude and gephyrin puncta size but this effect was not observed in NC, indicating a key role in neuron-astrocyte cross-talk. Blockade of monocarboxylate transport with α-Cyano-4-hydroxycinnamic acid (4CIN abolished iLTP both in NC and ANCC and in the latter model prevented also enlargement of gephyrin puncta. Similarly, blockade of glycogen phosphorylase with BAYU6751 prevented enlargement of gephyrin puncta upon iLTP induction. Finally, block of glutamine synthetase with methionine sulfoxide (MSO nearly abolished mIPSC increase in both NMDA stimulated cell groups but did not prevent enlargement of gephyrin puncta. In conclusion, we provide further evidence that GABAergic plasticity is strongly regulated by astrocytes and the underlying mechanisms involve key metabolic enzymes. Considering the strategic role of GABAergic interneurons, the plasticity described here indicates possible mechanism whereby metabolism regulates the network activity.

  12. Chimeric Plastics : a new class of thermoplastic

    Science.gov (United States)

    Sonnenschein, Mark

    A new class of thermoplastics (dubbed ``Chimerics'') is described that exhibits a high temperature glass transition followed by high performance elastomer properties, prior to melting. These transparent materials are comprised of co-continuous phase-separated block copolymers. One block is an amorphous glass with a high glass transition temperature, and the second is a higher temperature phase transition block creating virtual thermoreversible crosslinks. The material properties are highly influenced by phase separation on the order of 10-30 nanometers. At lower temperatures the polymer reflects the sum of the block copolymer properties. As the amorphous phase glass transition is exceeded, the virtual crosslinks of the higher temperature second phase dominate the plastic properties, resulting in rubber-like elasticity.

  13. Comprehensive Deformation Analysis of a Newly Designed Ni-Free Duplex Stainless Steel with Enhanced Plasticity by Optimizing Austenite Stability

    Science.gov (United States)

    Moallemi, Mohammad; Zarei-Hanzaki, Abbas; Eskandari, Mostafa; Burrows, Andrew; Alimadadi, Hossein

    2017-08-01

    A new metastable Ni-free duplex stainless steel has been designed with superior plasticity by optimizing austenite stability using thermodynamic calculations of stacking fault energy and with reference to literature findings. Several characterization methods comprising optical microscopy, magnetic phase measurements, X-ray diffraction (XRD) and electron backscattered diffraction were employed to study the plastic deformation behavior and to identify the operating plasticity mechanisms. The results obtained show that the newly designed duplex alloy exhibits some extraordinary mechanical properties, including an ultimate tensile strength of 900 MPa and elongation to fracture of 94 pct due to the synergistic effects of transformation-induced plasticity and twinning-induced plasticity. The deformation mechanism of austenite is complex and includes deformation banding, strain-induced martensite formation, and deformation-induced twinning, while the ferrite phase mainly deforms by dislocation slip. Texture analysis indicates that the Copper and Rotated Brass textures in austenite (FCC phase) and {001} texture in ferrite and martensite (BCC phases) are the main active components during tensile deformation. The predominance of these components is logically related to the strain-induced martensite and/or twin formation.

  14. MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY

    International Nuclear Information System (INIS)

    Lander, S. K.

    2016-01-01

    The activity of magnetars is believed to be powered by colossal magnetic energy reservoirs. We sketch an evolutionary picture in which internal field evolution in magnetars generates a twisted corona, from which energy may be released suddenly in a single giant flare, or more gradually through smaller outbursts and persistent emission. Given the ages of magnetars and the energy of their giant flares, we suggest that their evolution is driven by a novel mechanism: magnetic flux transport/decay due to persistent plastic flow in the crust, which would invalidate the common assumption that the crustal lattice is static and evolves only under Hall drift and Ohmic decay. We estimate the field strength required to induce plastic flow as a function of crustal depth, and the viscosity of the plastic phase. The star’s superconducting core may also play a role in magnetar field evolution, depending on the star’s spindown history and how rotational vortices and magnetic fluxtubes interact.

  15. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  16. Developmental Plasticity in Child Growth and Maturation

    Directory of Open Access Journals (Sweden)

    Ze'ev eHochberg

    2011-09-01

    Full Text Available The ability of a given genotype to produce different phenotypes in response to different environments is termed "plasticity", and is part of the organism's "adaptability" to environmental cues. The expressions of suites of genes, particularly during development or life-history transitions, probably underlie the fundamental plasticity of an organism. Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to organisms under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology, child growth and maturation, and long-term health and longevity. Developmental origins of health and disease and life history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies for child growth and maturation in response to local ecological and/or social conditions. The window of developmental plasticity extends from conception to early childhood, and even beyond to the transition from juvenility to adoelscence, and could be transmitted transgenerationally. It involves epigenetic responses to environmental changes, which exert their effects during life history phase-transitions.

  17. X-ray measurement of plastic strain by means of Eshelby/Mori-Tanaka model and its application

    International Nuclear Information System (INIS)

    Sasaki, Toshihiko; Lin, Zheng; Hirose, Yukio

    1997-01-01

    A new method is proposed in this paper for determining plastic strains in composite materials using the X-ray diffraction method. The present method was derived by using both Eshelby's approach and the Mori-Tanaka theory to express the stress state in composite materials instead of the elasticity in single-phase materials which is used in the conventional method of X-ray stress measurement. It was found that the plastic strain can be determined from the slope of the linear relation between lattice strains measured by the X-ray diffraction technique and sin 2 ψ using almost the same procedure as that for determining stresses by the conventional X-ray method. The results on ferritic and austenitic dual-phase stainless steel are shown. We discuss the effects of a uniaxial tensile load in a range of plastic deformation on the field of plastic strain as well as on residual macro-, micro- and phase stresses built up in the sample. (author)

  18. Pain perception is increased in congenital but not late onset blindness

    DEFF Research Database (Denmark)

    Slimani, Hocine; Danti, Sabrina; Ptito, Maurice

    2014-01-01

    There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown that congenit......There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown...... that congenitally and late blind individuals show differences in their degree of compensatory plasticity, we here address the question whether late blind individuals also show hypersensitivity to nociceptive stimulation. We therefore compared pain thresholds and responses to supra-threshold nociceptive stimuli...... in congenitally blind, late blind and normally sighted volunteers. Participants also filled in questionnaires measuring attention and anxiety towards pain in everyday life. Results show that late blind participants have pain thresholds and ratings of supra-threshold heat nociceptive stimuli similar...

  19. CaMKII knockdown affects both early and late phases of olfactory long-term memory in the honeybee.

    Science.gov (United States)

    Scholl, Christina; Kübert, Natalie; Muenz, Thomas S; Rössler, Wolfgang

    2015-12-01

    Honeybees are able to solve complex learning tasks and memorize learned information for long time periods. The molecular mechanisms mediating long-term memory (LTM) in the honeybee Apis mellifera are, to a large part, still unknown. We approached this question by investigating the potential function of the calcium/calmodulin-dependent protein kinase II (CaMKII), an enzyme known as a 'molecular memory switch' in vertebrates. CaMKII is able to switch to a calcium-independent constitutively active state, providing a mechanism for a molecular memory and has further been shown to play an essential role in structural synaptic plasticity. Using a combination of knockdown by RNA interference and pharmacological manipulation, we disrupted the function of CaMKII during olfactory learning and memory formation. We found that learning, memory acquisition and mid-term memory were not affected, but all manipulations consistently resulted in an impaired LTM. Both early LTM (24 h after learning) and late LTM (72 h after learning) were significantly disrupted, indicating the necessity of CaMKII in two successive stages of LTM formation in the honeybee. © 2015. Published by The Company of Biologists Ltd.

  20. Numerical Study of the Plasticity-Induced Stabilization Effect on Martensitic Transformations in Shape Memory Alloys

    Science.gov (United States)

    Junker, Philipp; Hempel, Philipp

    2017-12-01

    It is well known that plastic deformations in shape memory alloys stabilize the martensitic phase. Furthermore, the knowledge concerning the plastic state is crucial for a reliable sustainability analysis of construction parts. Numerical simulations serve as a tool for the realistic investigation of the complex interactions between phase transformations and plastic deformations. To account also for irreversible deformations, we expand an energy-based material model by including a non-linear isotropic hardening plasticity model. An implementation of this material model into commercial finite element programs, e.g., Abaqus, offers the opportunity to analyze entire structural components at low costs and fast computation times. Along with the theoretical derivation and expansion of the model, several simulation results for various boundary value problems are presented and interpreted for improved construction designing.

  1. solid phase extraction method for selective determination

    African Journals Online (AJOL)

    FATOKI

    determination of phthalate ester plasticizers in rivers and marine water samples. Of the ... samples that receive effluent from industries that use phthalate esters. ... Keywords Phthalates, Plasticizers, Solid Phase Gas Chromatography.

  2. Constitutive modelling and identification of parameters of the plastic strain-induced martensitic transformation in 316L stainless steel at cryogenic temperatures

    CERN Document Server

    Garion, C; Sgobba, Stefano

    2006-01-01

    The present paper is focused on constitutive modelling and identification of parameters of the relevant model of plastic strain- induced martensitic transformation in austenitic stainless steels at low temperatures. The model used to describe the FCCrightward arrow BCC phase transformation in austenitic stainless steels is based on the assumption of linearization of the most intensive part of the transformation curve. The kinetics of phase transformation is described by three parameters: transformation threshold (p/sub xi/), slope (A) and saturation level (xi/sub L/). It is assumed that the phase transformation is driven by the accumulated plastic strain p. In addition, the intensity of plastic deformation is strongly coupled to the phase transformation via the description of mixed kinematic /isotropic linear plastic hardening based on the Mori-Tanaka homogenization. The theory of small strains is applied. Small strain fields, corresponding to phase transformation, are decomposed into the volumic and the shea...

  3. A Preliminary fMRI Study of a Novel Self-Paced Written Fluency Task: Observation of Left-Hemispheric Activation, and Increased Frontal Activation in Late vs. Early Task Phases

    Directory of Open Access Journals (Sweden)

    Laleh eGolestanirad

    2015-03-01

    Full Text Available Neuropsychological tests of verbal fluency are very widely used to characterize impaired cognitive function. For clinical neuroscience studies and potential medical applications, measuring the brain activity that underlies such tests with functional magnetic resonance imaging (fMRI is of significant interest - but a challenging proposition because overt speech can cause signal artifacts, which tend to worsen as the duration of speech tasks becomes longer. In a novel approach, we present the group brain activity of 12 subjects who performed a self-paced written version of phonemic fluency using fMRI-compatible tablet technology that recorded responses and provided task-related feedback on a projection screen display, over long-duration task blocks (60 s. As predicted, we observed robust activation in the left anterior inferior and medial frontal gyri, consisting with previously reported results of verbal fluency tasks which established the role of these areas in strategic word retrieval. In addition, the number of words produced in the late phase (last 30 s of written phonemic fluency was significantly less (p < 0.05 than the number produced in the early phase (first 30 s. Activation during the late phase vs. the early phase was also assessed from the first 20 s and last 20 s of task performance, which eliminated the possibility that the sluggish hemodynamic response from the early phase would affect the activation estimates of the late phase. The last 20 s produced greater activation maps covering extended areas in bilateral precuneus, cuneus, middle temporal gyrus, insula, middle frontal gyrus and cingulate gyrus. Among them, greater activation was observed in the bilateral middle frontal gyrus (Brodmann area BA 9 and cingulate gyrus (BA 24, 32 likely as part of the initiation, maintenance, and shifting of attentional resources.

  4. Magical Engineering Plastic

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwang Ung

    1988-01-15

    This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

  5. Magical Engineering Plastic

    International Nuclear Information System (INIS)

    Kim, Gwang Ung

    1988-01-01

    This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

  6. A multi-scale model of martensitic transformation plasticity

    NARCIS (Netherlands)

    Kouznetsova, V.G.; Geers, M.G.D.

    2008-01-01

    The remarkable mechanical engineering properties of many advanced steels, e.g. TRIP steels and metastable austenitic stainless steels, are related to their complex microstructural behaviour, resulting from the interaction between plastic deformation of the phases and the austenite to martensite

  7. International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review.

    Science.gov (United States)

    Xanthos, Dirk; Walker, Tony R

    2017-05-15

    Marine plastic pollution has been a growing concern for decades. Single-use plastics (plastic bags and microbeads) are a significant source of this pollution. Although research outlining environmental, social, and economic impacts of marine plastic pollution is growing, few studies have examined policy and legislative tools to reduce plastic pollution, particularly single-use plastics (plastic bags and microbeads). This paper reviews current international market-based strategies and policies to reduce plastic bags and microbeads. While policies to reduce microbeads began in 2014, interventions for plastic bags began much earlier in 1991. However, few studies have documented or measured the effectiveness of these reduction strategies. Recommendations to further reduce single-use plastic marine pollution include: (i) research to evaluate effectiveness of bans and levies to ensure policies are having positive impacts on marine environments; and (ii) education and outreach to reduce consumption of plastic bags and microbeads at source. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Plastic debris ingestion by marine catfish: an unexpected fisheries impact.

    Science.gov (United States)

    Possatto, Fernanda E; Barletta, Mário; Costa, Monica F; do Sul, Juliana A Ivar; Dantas, David V

    2011-05-01

    Plastic marine debris is a pervasive type of pollution. River basins and estuaries are a source of plastics pollution for coastal waters and oceans. Estuarine fauna is therefore exposed to chronic plastic pollution. Three important catfish species [Cathorops spixii (N=60), Cathorops agassizii (N=60) and Sciades herzbergii (N=62)] from South Western Atlantic estuaries were investigated in a tropical estuary of the Brazilian Northeast in relation to their accidental ingestion of plastic marine debris. Individuals from all three species had ingested plastics. In C. spixii and C. agassizii, 18% and 33% of individuals had plastic debris in their stomachs, respectively. S. herzbergii showed 18% of individuals were contaminated. All ontogenetic phases (juveniles, sub-adults and adults) were contaminated. Nylon fragments from cables used in fishery activities (subsistence, artisanal and commercial) played a major role in this contamination. These catfish spend their entire life cycles within the estuary and are an important feeding resource for larger, economically important, species. It is not yet possible to quantify the scale and depth of the consequences of this type of pollution. However, plastics are well known threat to living resources in this and other estuaries. Conservation actions will need to from now onto take plastics pollution into consideration. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Late phase cell cycle proteins in Alzheimer’s disease: a possible target for therapy?

    KAUST Repository

    Bajic, Vladan

    2017-02-22

    Alzheimer’s disease (AD) is represented by neuronal loss and this loss is correlated to a constant state of neuronal instability induced by intrinsic and extrinsic factors. In this paper data is presented regarding the possible roles of late phase cell cycle proteins in normal and affected neurons with the goal that understanding the mechanisms involved in the regulation of these proteins may represent a novel strategy for AD treatment. The results demonstrate a relative differential pattern of expression of certain proteins (APC/C, Mad1 and Mad2, Bub R1, Bub1, CDK 11, cohesin subunit Rad 21 and astrin) in the AD brain versus age matched controls, and it is suggested that targeting these proteins might translate into potential treatments for AD. Although the data presented here is of some interest, the ability to translate such information into clinical applications is often a challenge.

  10. Late phase cell cycle proteins in Alzheimer’s disease: a possible target for therapy?

    KAUST Repository

    Bajic, Vladan; B. Bajic, Vladimir; Zivkovic, Lada; Arendt, Thomas; Perry, George; Spremo-Potparevic, Biljana

    2017-01-01

    Alzheimer’s disease (AD) is represented by neuronal loss and this loss is correlated to a constant state of neuronal instability induced by intrinsic and extrinsic factors. In this paper data is presented regarding the possible roles of late phase cell cycle proteins in normal and affected neurons with the goal that understanding the mechanisms involved in the regulation of these proteins may represent a novel strategy for AD treatment. The results demonstrate a relative differential pattern of expression of certain proteins (APC/C, Mad1 and Mad2, Bub R1, Bub1, CDK 11, cohesin subunit Rad 21 and astrin) in the AD brain versus age matched controls, and it is suggested that targeting these proteins might translate into potential treatments for AD. Although the data presented here is of some interest, the ability to translate such information into clinical applications is often a challenge.

  11. Elastomer modified polypropylene–polyethylene blends as matrices for wood flour–plastic composites

    Science.gov (United States)

    Craig Clemons

    2010-01-01

    Blends of polyethylene (PE) and polypropylene (PP) could potentially be used as matrices for wood–plastic composites (WPCs). The mechanical performance and morphology of both the unfilled blends and wood-filled composites with various elastomers and coupling agents were investigated. Blending of the plastics resulted in either small domains of the minor phase in a...

  12. A Scoping Analysis Of The Impact Of SiC Cladding On Late-Phase Accident Progression Involving Core–Concrete Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, M. T. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-11-01

    The overall objective of the current work is to carry out a scoping analysis to determine the impact of ATF on late phase accident progression; in particular, the molten core-concrete interaction portion of the sequence that occurs after the core debris fails the reactor vessel and relocates into containment. This additional study augments previous work by including kinetic effects that govern chemical reaction rates during core-concrete interaction. The specific ATF considered as part of this study is SiC-clad UO2.

  13. Plastic deformation of silicon dendritic web ribbons during the growth

    Science.gov (United States)

    Cheng, L. J.; Dumas, K. A.; Su, B. M.; Leipold, M. H.

    1984-01-01

    The distribution of slip dislocations in silicon dendritic web ribbons due to plastic deformation during the cooling phase of the growth was studied. The results show the existence of two distinguishable stress regions across the ribbon formed during the plastic deformation stage, namely, shear stress at the ribbon edges and tensile stress at the middle. In addition, slip dislocations caused by shear stress near the edges appear to originate at the twin plane.

  14. Polar bears (Ursus maritimus mating during late June on the pack ice of northern Svalbard, Norway

    Directory of Open Access Journals (Sweden)

    Thomas G. Smith

    2015-03-01

    Full Text Available Polar bears are seasonal breeders and typically mate from late March to early May. Implantation is, however, delayed until autumn, which can allow plasticity in the date of mating. As for other seasonal breeders, a rapid return to estrus after the loss of dependent offspring can be expected, even into the summer. A few earlier observations and dissections of dead animals suggest that polar bears are able to mate in summer. We report on a mating incident on 29 June 2014, the first documented mating this late in the season among wild polar bears. The female had lost her dependent cub during the period prior to the mating event. We speculate that she lost this cub late in the mating season, entered estrus and successfully mated in late June.

  15. Crack nucleation and elastic / plastic deformation of TiAl alloys investigated by in-situ loaded atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, F.; Pyczak, F.; Neumeier, S.; Göken, M.

    2017-03-24

    The crack propagation mechanisms of γ-titanium aluminides with fully lamellar microstructure have been studied using in-situ deformation in the Atomic Force Microscope (AFM). AFM demonstrated the unique capability to detect elastic as well as plastic deformation during in-situ tests from topography changes on the surface. It was found that the crack nucleation, which can occur at γ/γ and α{sub 2}/γ interfaces as well as inside the γ-phase, is always preceded by strong local elastic deformation. No cracking inside the α{sub 2}-phase was observed. The elastic and plastic deformation was confined inside the γ-phase and especially pronounced near interfaces which can be explained by the differences of the elastic and plastic deformation behavior of the γ- and α{sub 2}- phase.

  16. Inspecting plastic deformation of Pd by means of fractal geometry

    International Nuclear Information System (INIS)

    Eftekhari, Ali

    2007-01-01

    The influence of phase transformation-induced plastic deformation in Pd|H system on the electrode surface was investigated. Since the Pd surface is subject of severe plastic deformation during this process, the structure and roughness of the electrode surface significantly change. Quantitative analysis of the electrode surfaces for comparative study of such changes is a valuable tool to inspect the plastic deformation induced. Fractal dimension can be used as a quantitative measure for this purpose. Since inappropriate methods may lead to significant errors, an appropriate approach was proposed for the determination of fractal dimensions in such systems. It was demonstrated that the surface roughness generated is mainly due to the plastic deformation induced, not the other side processes, as the electrodes were coated with a uniform layer of gold with thickness smaller than 10 nm. Since plastic deformation is due to hydrogen insertion/extraction and occurs in atomic-scale, it is necessary to divide structural changes appeared in nano- and micro-scale

  17. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    Science.gov (United States)

    Hartl, D. J.; Lagoudas, D. C.

    2009-10-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation.

  18. Constitutive modeling and structural analysis considering simultaneous phase transformation and plastic yield in shape memory alloys

    International Nuclear Information System (INIS)

    Hartl, D J; Lagoudas, D C

    2009-01-01

    The new developments summarized in this work represent both theoretical and experimental investigations of the effects of plastic strain generation in shape memory alloys (SMAs). Based on the results of SMA experimental characterization described in the literature and additional testing described in this work, a new 3D constitutive model is proposed. This phenomenological model captures both the conventional shape memory effects of pseudoelasticity and thermal strain recovery, and additionally considers the initiation and evolution of plastic strains. The model is numerically implemented in a finite element framework using a return mapping algorithm to solve the constitutive equations at each material point. This combination of theory and implementation is unique in its ability to capture the simultaneous evolution of recoverable transformation strains and irrecoverable plastic strains. The consideration of isotropic and kinematic plastic hardening allows the derivation of a theoretical framework capturing the interactions between irrecoverable plastic strain and recoverable strain due to martensitic transformation. Further, the numerical integration of the constitutive equations is formulated such that objectivity is maintained for SMA structures undergoing moderate strains and large displacements. The implemented model has been used to perform 3D analysis of SMA structural components under uniaxial and bending loads, including a case of local buckling behavior. Experimentally validated results considering simultaneous transformation and plasticity in a bending member are provided, illustrating the predictive accuracy of the model and its implementation

  19. Strain hardening behavior and microstructural evolution during plastic deformation of dual phase, non-grain oriented electrical and AISI 304 steels

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Guilherme Corrêa; Gonzalez, Berenice Mendonça; Arruda Santos, Leandro de, E-mail: leandro.arruda@demet.ufmg.br

    2017-01-27

    Strain hardening behavior and microstructural evolution of non-grain oriented electrical, dual phase, and AISI 304 steels, subjected to uniaxial tensile tests, were investigated in this study. Tensile tests were performed at room temperature and the strain hardening behavior of the steels was characterized by three different parameters: modified Crussard–Jaoul stages, strain hardening rate and instantaneous strain hardening exponent. Optical microscopic analysis, X-ray diffraction measurements, phase quantification by Rietveld refinement and hardness tests were also carried out in order to correlate the microstructural and mechanical responses to plastic deformation. Distinct strain hardening stages were observed in the steels in terms of the instantaneous strain hardening exponent and the strain hardening rate. The dual phase and non-grain oriented steels exhibited a two-stage strain hardening behavior while the AISI 304 steel displayed multiple stages, resulting in a more complex strain hardening behavior. The dual phase steels showed a high work hardening capacity in stage 1, which was gradually reduced in stage 2. On the other hand, the AISI 304 steel showed high strain hardening capacity, which continued to increase up to the tensile strength. This is a consequence of its additional strain hardening mechanism, based on a strain-induced martensitic transformation, as shown by the X-ray diffraction and optical microscopic analyses.

  20. Rational analysis and index of plasticity of clays for extrusion evaluation

    International Nuclear Information System (INIS)

    Silva, A.R.; Guimaraes Filho, M.A.S.; Santos, C.V.P.; Fagury Neto, E.; Rabelo, A.A.

    2011-01-01

    In the microregion Maraba, in the southeast paraense, there's a important industrial park in the area of red ceramic due to the quality of the extracted clays in the proximities of their rivers. With the intention of collaborating for the production of tiles and structural blocks of quality, in this work the rational analysis of clays was accomplished, through the relationship of the qualitative X-ray diffraction and X-ray fluorescence results. Was possible to quantify the present phases in the collected clays and these results were correlated to the Atterberg's limits - plasticity and liquidity limitsand the respective plasticity indexes - making possible to classify the clays in areas of great and acceptable extrusion. The results of the rational analysis demonstrated that the analyzed clays are plastic kaolinites and don't present quantitative differences very accentuated among the present phases detected besides they possess an area of acceptable extrusion naturally. (author)

  1. Phase separation and shape deformation of two-phase membranes

    International Nuclear Information System (INIS)

    Jiang, Y.; Lookman, T.; Saxena, A.

    2000-01-01

    Within a coupled-field Ginzburg-Landau model we study analytically phase separation and accompanying shape deformation on a two-phase elastic membrane in simple geometries such as cylinders, spheres, and tori. Using an exact periodic domain wall solution we solve for the shape and phase separating field, and estimate the degree of deformation of the membrane. The results are pertinent to preferential phase separation in regions of differing curvature on a variety of vesicles. (c) 2000 The American Physical Society

  2. Temperature and phase dependence of positron lifetimes in solid cyclohexane

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard

    1985-01-01

    The temperature dependence of position lifetimes in both the brittle and plastic phases of cyclohaxane has been examined. Long-lived components in both phases are associated with the formation of positronium (Ps). Two long lifetimes attributable to ortho-Ps are resolvable in the plastic phase....... The longer of these (≈ 2.5 ns), which is temperature dependent, is ascribed to ortho-Ps trapped at vacancies. The shorter lifetime (≈ 0.9 ns), shows little temperature dependence. In contrast to most other plastic crystals, no sigmoidal behaviour of the average ortho-Ps lifetime is observed. A possibility...

  3. High-carbon chromium steel resistance to small plastic deformation

    International Nuclear Information System (INIS)

    Gajduchenya, V.F.; Madyanov, S.A.; Apaev, B.A.; Kirillov, Yu.V.; Sokolov, L.D.

    1978-01-01

    The phase composition of a steel with 1.08% C and 2.1% Cr, and the variation in the level of microstresses in the matrix as related to the annealing temperature in the range of 400-600 deg C and in the applied compression stress were investigated. To study the phase composition, and chromium content in the α-solution and the carbide phases, magnetic, chemical, and X-ray spectrum analyses were carried out. The change in the level of microstresses was determined roentgenographically. During the stress relaxation test at temperatures of 20-180 deg C, the mechanism of plastic deformation near the yield point was investigated. It is shown that three dislocation mechanisms operate in high-carbon chromium steel under the conditions at hand: overcoming the Pierls-Nabarro barriers by the dislocations, overcoming the stress fields of coherent carbide particles by dislocations, and circumvention of second-phase particles by dislocations. The dependence of the realization of the different plastic deformation mechanisms on the number of carbide particles and the chromium concentration in the matrix was established. The thermally activated nature of the motion of the dislocations under conditions of stress relaxation at an elevated temperature is noted

  4. High pressure phase transformations revisited

    Science.gov (United States)

    Levitas, Valery I.

    2018-04-01

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  5. High pressure phase transformations revisited.

    Science.gov (United States)

    Levitas, Valery I

    2018-04-25

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  6. An Experimental Study on the Thermal Performance of Phase-Change Material and Wood-Plastic Composites for Building Roofs

    Directory of Open Access Journals (Sweden)

    Min Hee Chung

    2017-02-01

    Full Text Available We assessed the usefulness of phase-change material (PCM-based thermal plates fabricated from wood-plastic composites (WPCs in mitigating the urban heat island effect. The thermal performance of plates containing PCMs with two different melting temperatures and with two different albedo levels was evaluated. The results showed that the PCM with a melting temperature of 44 °C maintained lower surface and inner temperatures than the PCM with a melting temperature of 25 °C. Moreover, a higher surface albedo resulted in a lower surface temperature. However, the thermal performance of PCMs with different melting temperatures but the same surface albedo did not differ. Using PCM-based materials in roof finishing materials can reduce surface temperatures and improve thermal comfort.

  7. Nanobarium Titanate As Supplement To Accelerate Plastic Waste Biodegradation By Indigenous Bacterial Consortia

    Science.gov (United States)

    Kapri, Anil; Zaidi, M. G. H.; Goel, Reeta

    2009-06-01

    Plastic waste biodegradation studies have seen several developmental phases from the discovery of potential microbial cultures, inclusion of photo-oxidizable additives into the polymer chain, to the creation of starch-embedded biodegradable plastics. The present study deals with the supplementation of nanobarium titanate (NBT) in the minimal broth in order to alter the growth-profiles of the Low-density polyethylene (LDPE) degrading consortia. The pro-bacterial influence of the nanoparticles could be seen by substantial changes such as shortening of the lag phase and elongation of the exponential as well as stationary growth phases, respectively, which eventually increase the biodegradation efficiency. In-vitro biodegradation studies revealed better dissolution of LDPE in the presence of NBT as compared to control. Significant shifting in λ-max values was observed in the treated samples through UV-Vis spectroscopy, while Fourier transform infrared spectroscopy (FTIR) and simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) further confirmed the breakage and formation of bonds in the polymer backbone. Therefore, this study suggests the implementation of NBT as nutritional additive for plastic waste management through bacterial growth acceleration.

  8. Magnetic silica nanomaterials for solid-phase extraction combined with dispersive liquid-liquid microextraction of ultra-trace quantities of plasticizers

    International Nuclear Information System (INIS)

    Yamini, Yadollah; Faraji, Mohammad; Adeli, Mahnaz

    2015-01-01

    We are presenting surface modified magnetic silica nanoparticles (m-Si-NPs) for use in solid-phase extraction combined with dispersive liquid-liquid microextraction (DLLME). The m-Si-NPs were surface-functionalized with octadecyl groups to give a material for the extraction of the plasticizers dibutyl phthalate, di(2-ethylhexyl) adipate and di(2-ethylhexyl) phthalate from water samples. The functionalized m-Si-NPs were characterized by scanning electron microscopy, FTIR spectroscopy, thermal gravimetric analysis, and vibrating sample magnetometry. The results showed that the m-Si-NPs were well functionalized with octadecyl groups. The effects of various experimental variables on the extraction efficiencies were investigated. The analytes were quantified by GC/FID. Under optimal conditions, the calibration plots are linear in the range from 0.01 to 100 μg∙L -1 , and very high enrichment factors (mean value ∼20,000) were obtained. As a result of the high enrichment factors, the detection limits are as low as 2–3 ng∙L -1 . The method was successfully employed to the extraction of the plasticizers from (spiked) water samples, and recoveries are in the order of 93.9 to 106.7 %. The method is low cost, fast, and very sensitive (author)

  9. Hydraulic separation of plastic wastes: Analysis of liquid-solid interaction.

    Science.gov (United States)

    Moroni, Monica; Lupo, Emanuela; La Marca, Floriana

    2017-08-01

    The separation of plastic wastes in mechanical recycling plants is the process that ensures high-quality secondary raw materials. An innovative device employing a wet technology for particle separation is presented in this work. Due to the combination of the characteristic flow pattern developing within the apparatus and density, shape and size differences among two or more polymers, it allows their separation into two products, one collected within the instrument and the other one expelled through its outlet ducts. The kinematic investigation of the fluid flowing within the apparatus seeded with a passive tracer was conducted via image analysis for different hydraulic configurations. The two-dimensional turbulent kinetic energy results strictly connected to the apparatus separation efficacy. Image analysis was also employed to study the behaviour of mixtures of passive tracer and plastic particles with different physical characteristics in order to understand the coupling regime between fluid and solid phases. The two-dimensional turbulent kinetic energy analysis turned out to be fundamental to this aim. For the tested operating conditions, two-way coupling takes place, i.e., the fluid exerts an influence on the plastic particle and the opposite occurs too. Image analysis confirms the outcomes from the investigation of the two-phase flow via non-dimensional numbers (particle Reynolds number, Stokes number and solid phase volume fraction). Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Observations of the late superhump in VW Hydri

    International Nuclear Information System (INIS)

    Van Der Woerd, H.; Van Der Klis, M.; Van Paradijs, J.; Beuermann, K.; Motch, C.

    1988-01-01

    This paper presents the results of simultaneous optical and near-IR photometry, optical fast spectroscopy, and Exosat X-ray observations of the dwarf nova VW Hyi, obtained simultaneously during three consecutive orbital cycles, approximately two days after the 1983 November superoutburst terminated. The optical data show clear evidence for a late superhump, which is shifted + 0.7 in phase relative to the orbital modulation. An attempt is made to derive from the observed spectral distribution the contribution of the late superhump. The orbital hump and the late superhump apparently are not related to each other. This important effect excludes all models, in which the late superhump phenomenon is interpreted in terms of variations in the bright-spot brightness. 43 references

  11. An all-solid-state electrochemical double-layer capacitor based on a plastic crystal electrolyte

    Directory of Open Access Journals (Sweden)

    Ali eaabouimrane

    2015-08-01

    Full Text Available A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C4H94NPF6, (10 molar % with succinonitrile, SCN, (N C−CH2−CH2−C N, [SCN-10%TBA-PF6]. The resultant waxy material shows a plastic crystalline phase that extend from -36 °C up to its melting at 23 °C. It shows a high ionic conductivity reaching 4 × 10−5 S/cm in the plastic crystal phase (15 °C and ~ 3 × 10−3 S/cm in the molten state (25 °C. These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC. The EDLC was assembled and its performance was tested by cyclic voltammetry, AC impedance spectroscopy and galvanostatic charge-discharge methods. Specific capacitance values in the range of 4-7 F/g. (of electrode active material were obtained in the plastic crystal phase at 15 °C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

  12. An All-Solid-State Electrochemical Double-Layer Capacitor Based on a Plastic Crystal Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Abouimrane, Ali; Belharouak, Ilias [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Abu-Lebdeh, Yaser A., E-mail: yaser.abu-lebdeh@nrc.gc.ca [Energy, Mining and Environment Portfolio and Automotive and Surface Transportation Portfolio, National Research Council of Canada, Ottawa, ON (Canada)

    2015-08-18

    A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C{sub 4}H{sub 9}){sub 4}-NPF{sub 6}, (10 molar %) with succinonitrile, SCN, (N≡C−CH{sub 2}−CH{sub 2}−C≡N), [SCN-10%TBA-PF{sub 6}]. The resultant waxy material shows a plastic crystalline phase that extends from −36°C up to its melting at 23°C. It shows a high ionic conductivity reaching 4 × 10{sup -5} S/cm in the plastic crystal phase (15°C) and ~ 3 × 10{sup -3} S/cm in the molten state (25°C). These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC). The EDLC was assembled, and its performance was tested by cyclic voltammetry, AC impedance spectroscopy, and galvanostatic charge–discharge methods. Specific capacitance values in the range of 4–7 F/g (of electrode active material) were obtained in the plastic crystal phase at 15°C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

  13. An All-Solid-State Electrochemical Double-Layer Capacitor Based on a Plastic Crystal Electrolyte

    International Nuclear Information System (INIS)

    Abouimrane, Ali; Belharouak, Ilias; Abu-Lebdeh, Yaser A.

    2015-01-01

    A plastic crystal, solid electrolyte was prepared by mixing tetrabutylammonium hexafluorophosphate salt, (C 4 H 9 ) 4 -NPF 6 , (10 molar %) with succinonitrile, SCN, (N≡C−CH 2 −CH 2 −C≡N), [SCN-10%TBA-PF 6 ]. The resultant waxy material shows a plastic crystalline phase that extends from −36°C up to its melting at 23°C. It shows a high ionic conductivity reaching 4 × 10 -5 S/cm in the plastic crystal phase (15°C) and ~ 3 × 10 -3 S/cm in the molten state (25°C). These properties along with the high electrochemical stability rendered the use of this material as an electrolyte in an electrochemical double-layer capacitor (EDLC). The EDLC was assembled, and its performance was tested by cyclic voltammetry, AC impedance spectroscopy, and galvanostatic charge–discharge methods. Specific capacitance values in the range of 4–7 F/g (of electrode active material) were obtained in the plastic crystal phase at 15°C, that although compare well with those reported for some polymer electrolytes, can be still enhanced with further development of the device and its components, and only demonstrate their great potential use for capacitors as a new application.

  14. Mixture theory for a thermoelasto-plastic porous solid considering fluid flow and internal mass exchange

    DEFF Research Database (Denmark)

    Ristinmaa, M.; Ottosen, N.S.; Johannesson, Björn

    2011-01-01

    A thermoelastic-plastic body consisting of two phases, a solid and a fluid, each comprising two constituents is considered where one constituent in one phase is allowed to exchange mass with another constituent (of the same substance) in the other phase. A large strain setting is adopted and the ......A thermoelastic-plastic body consisting of two phases, a solid and a fluid, each comprising two constituents is considered where one constituent in one phase is allowed to exchange mass with another constituent (of the same substance) in the other phase. A large strain setting is adopted......, and in particular, a general evolution law for the rate of deformation tensor related to mass exchange is proposed and this leads to general absorption and desorption evolution laws for mass exchange between two constituents (of the same substance), one belonging to the solid phase and the other to the fluid phase....... Equilibrium curves for absorption and desorption also emerge from the theory....

  15. Soil burial method for plastic degradation performed by Pseudomonas PL-01, Bacillus PL-01, and indigenous bacteria

    Science.gov (United States)

    Shovitri, Maya; Nafi'ah, Risyatun; Antika, Titi Rindi; Alami, Nur Hidayatul; Kuswytasari, N. D.; Zulaikha, Enny

    2017-06-01

    Lately, plastic bag is becoming the most important pollutant for environment since it is difficult to be naturally degraded due to it consists of long hydrocarbon polymer chains. Our previous study indicated that our pure isolate Pseudomonas PL-01 and Bacillus PL-01 could degrade about 10% plastic bag. This present study was aimed to find out whether Pseudomonas PL01 and Bacillus PL01 put a positive effect to indigenous bacteria from marginal area in doing plastic degradation with a soil burial method. Beach sand was used as a representative marginal area, and mangrove sediment was used as a comparison. Plastics were submerged into unsterile beach sand with 10% of Pseudomonas PL-01 or Bacillus PL-01 containing liquid minimal salt medium (MSM) separately, while other plastics were submerged into unsterile mangrove sediments. After 4, 8, 12 and 16 weeks, their biofilm formation on their plastic surfaces and plastic degradation were measured. Results indicated that those 2 isolates put positive influent on biofilm formation and plastic degradation for indigenous beach sand bacteria. Bacillus PL-01 put higher influent than Pseudomonas PL-01. Plastic transparent was preferable degraded than black and white plastic bag `kresek'. But anyhow, indigenous mangrove soil bacteria showed the best performance in biofilm formation and plastic degradation, even without Pseudomonas PL-01 or Bacillus PL-01 addition. Fourier Transform Infrared (FTIR) analysis complemented the results; there were attenuated peaks with decreasing peaks transmittances. This FTIR peaks indicated chemical functional group changes happened among the plastic compounds after 16 weeks incubation time.

  16. Ultra fine grained Ti prepared by severe plastic deformation

    Science.gov (United States)

    Lukáč, F.; Čížek, J.; Knapp, J.; Procházka, I.; Zháňal, P.; Islamgaliev, R. K.

    2016-01-01

    The positron annihilation spectroscopy was employed for characterisation of defects in pure Ti with ultra fine grained (UFG) structure. UFG Ti samples were prepared by two techniques based on severe plastic deformation (SPD): (i) high pressure torsion (HPT) and (ii) equal channel angular pressing (ECAP). Although HPT is the most efficient technique for grain refinement, the size of HPT-deformed specimens is limited. On the other hand, ECAP is less efficient in grain refinement but enables to produce larger samples more suitable for industrial applications. Characterisation of defects by positron annihilation spectroscopy was accompanied by hardness testing in order to monitor the development of mechanical properties of UFG Ti.

  17. Sharp-Wave Ripples Orchestrate the Induction of Synaptic Plasticity during Reactivation of Place Cell Firing Patterns in the Hippocampus

    Directory of Open Access Journals (Sweden)

    Josef H.L.P. Sadowski

    2016-03-01

    Full Text Available Place cell firing patterns reactivated during hippocampal sharp-wave ripples (SWRs in rest or sleep are thought to induce synaptic plasticity and thereby promote the consolidation of recently encoded information. However, the capacity of reactivated spike trains to induce plasticity has not been directly tested. Here, we show that reactivated place cell firing patterns simultaneously recorded from CA3 and CA1 of rat dorsal hippocampus are able to induce long-term potentiation (LTP at synapses between CA3 and CA1 cells but only if accompanied by SWR-associated synaptic activity and resulting dendritic depolarization. In addition, we show that the precise timing of coincident CA3 and CA1 place cell spikes in relation to SWR onset is critical for the induction of LTP and predictive of plasticity generated by reactivation. Our findings confirm an important role for SWRs in triggering and tuning plasticity processes that underlie memory consolidation in the hippocampus during rest or sleep.

  18. Mechanisms by Which Phenotypic Plasticity Affects Adaptive Divergence and Ecological Speciation.

    Science.gov (United States)

    Nonaka, Etsuko; Svanbäck, Richard; Thibert-Plante, Xavier; Englund, Göran; Brännström, Åke

    2015-11-01

    Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a critical role in the early stages of speciation, prior to genetic divergence, by facilitating fast phenotypic divergence. The ability to plastically express alternative phenotypes may, however, interfere with the early phase of the formation of reproductive barriers, especially in the absence of geographic barriers. Here, we quantitatively investigate mechanisms under which plasticity can influence progress toward adaptive genetic diversification and ecological speciation. We use a stochastic, individual-based model of a predator-prey system incorporating sexual reproduction and mate choice in the predator. Our results show that evolving plasticity promotes the evolution of reproductive isolation under diversifying environments when individuals are able to correctly select a more profitable habitat with respect to their phenotypes (i.e., adaptive habitat choice) and to assortatively mate with relatively similar phenotypes. On the other hand, plasticity facilitates the evolution of plastic generalists when individuals have a limited capacity for adaptive habitat choice. We conclude that plasticity can accelerate the evolution of a reproductive barrier toward adaptive diversification and ecological speciation through enhanced phenotypic differentiation between diverging phenotypes.

  19. Selective loss of bi-directional synaptic plasticity in the direct and indirect striatal output pathways accompanies generation of parkinsonism and l-DOPA induced dyskinesia in mouse models.

    Science.gov (United States)

    Thiele, Sherri L; Chen, Betty; Lo, Charlotte; Gertler, Tracey S; Warre, Ruth; Surmeier, James D; Brotchie, Jonathan M; Nash, Joanne E

    2014-11-01

    Parkinsonian symptoms arise due to over-activity of the indirect striatal output pathway, and under-activity of the direct striatal output pathway. l-DOPA-induced dyskinesia (LID) is caused when the opposite circuitry problems are established, with the indirect pathway becoming underactive, and the direct pathway becoming over-active. Here, we define synaptic plasticity abnormalities in these pathways associated with parkinsonism, symptomatic benefits of l-DOPA, and LID. We applied spike-timing dependent plasticity protocols to cortico-striatal synapses in slices from 6-OHDA-lesioned mouse models of parkinsonism and LID, generated in BAC transgenic mice with eGFP targeting the direct or indirect output pathways, with and without l-DOPA present. In naïve mice, bidirectional synaptic plasticity, i.e. LTP and LTD, was induced, resulting in an EPSP amplitude change of approximately 50% in each direction in both striatal output pathways, as shown previously. In parkinsonism and dyskinesia, both pathways exhibited unidirectional plasticity, irrespective of stimulation paradigm. In parkinsonian animals, the indirect pathway only exhibited LTP (LTP protocol: 143.5±14.6%; LTD protocol 177.7±22.3% of baseline), whereas the direct pathway only showed LTD (LTP protocol: 74.3±4.0% and LTD protocol: 63.3±8.7%). A symptomatic dose of l-DOPA restored bidirectional plasticity on both pathways to levels comparable to naïve animals (Indirect pathway: LTP protocol: 124.4±22.0% and LTD protocol: 52.1±18.5% of baseline. Direct pathway: LTP protocol: 140.7±7.3% and LTD protocol: 58.4±6.0% of baseline). In dyskinesia, in the presence of l-DOPA, the indirect pathway exhibited only LTD (LTP protocol: 68.9±21.3% and LTD protocol 52.0±14.2% of baseline), whereas in the direct pathway, only LTP could be induced (LTP protocol: 156.6±13.2% and LTD protocol 166.7±15.8% of baseline). We conclude that normal motor control requires bidirectional plasticity of both striatal outputs

  20. The existence of a plastic phase and a solid-liquid dynamical bistability region in small fullerene cluster (C60)7: molecular dynamics simulation

    International Nuclear Information System (INIS)

    Piatek, A; Dawid, A; Gburski, Z

    2006-01-01

    We have simulated (by the molecular dymanics (MD) method) the dynamics of fullerenes (C 60 ) in an extremely small cluster composed of only as many as seven C 60 molecules. The interaction is taken to be the full 60-site pairwise additive Lennard-Jones (LJ) potential which generates both translational and anisotropic rotational motions of each molecule. Our atomically detailed MD simulations discover the plastic phase (no translations but active reorientations of fullerenes) at low energies (temperatures) of the (C 60 ) 7 cluster. We provide the in-depth evidence of the dynamical solid-liquid bistability region in the investigated cluster. Moreover, we confirm the existence of the liquid phase in (C 60 ) 7 , the finding of Gallego et al (1999 Phys. Rev. Lett. 83 5258) obtained earlier on the basis of Girifalco's model, which assumes single-site only and spherically symmetrical interaction between C 60 molecules. We have calculated the translational and angular velocity autocorrelation functions and estimated the diffusion coefficient of fullerene in the liquid phase

  1. Evaporite-hosted native sulfur in Trans-Pecos Texas: Relation to late-phase basin and range deformation

    International Nuclear Information System (INIS)

    Hentz, T.F.; Henry, C.D.

    1989-01-01

    Major deposits of biogenic native sulfur are associated with narrow, northeast-trending grabens and normal faults that disrupt the gently tilted, east-dipping Upper Permian evaporite succession of the western Delaware Basin in Trans-Pecos Texas. Orebodies are restricted to geologic traps in the fractured and dissolution-modified downfaulted blocks of the grabens. Other parallel, regionally distributed grabens and normal faults are commonly the sites of noncommercial sulfur deposits and genetically related secondary-replacement (diagenetic) limestone bodies. The sulfur-bearing structures probably formed during the later of two episodes of Basin and Range extension that have not previously been differentiated in Texas but are well defined elsewhere in the western United States. In Texas several lines of evidence collectively support the existence of late-phase, northwest-directed extension that was initiated in the middle Miocene

  2. A PAF receptor antagonist inhibits acute airway inflammation and late-phase responses but not chronic airway inflammation and hyperresponsiveness in a primate model of asthma

    Directory of Open Access Journals (Sweden)

    R. H. Gundel

    1992-01-01

    Full Text Available We have examined the effects of a PAF receptor antagonist, WEB 2170, on several indices of acute and chronic airway inflammation and associated changes in lung function in a primate model of allergic asthma. A single oral administration WEB 2170 provided dose related inhibition of the release of leukotriene C4 (LTC4 and prostaglandin D2 (PGD2 recovered and quantified in bronchoalveolar lavage (BAL fluid obtained during the acute phase response to inhaled antigen. In addition, oral WEB 2170 treatment in dual responder primates blocked the acute influx of neutrophils into the airways as well as the associated late-phase airway obstruction occurring 6 h after antigen inhalation. In contrast, a multiple dosing regime with WEB 2170 (once a day for 7 consecutive days failed to reduce the chronic airway inflammation (eosinophilic and associated airway hyperresponsiveness to inhaled methacholine that is characteristic of dual responder monkeys. Thus, we conclude that the generation of PAF following antigen inhalation contributes to the development of lipid mediators, acute airway inflammation and associated late-phase airway obstruction in dual responder primates; however, PAF does not play a significant role in the maintenance of chronic airway inflammation and associated airway hyperresponsiveness in this primate model.

  3. Effect of early and late mobilisation on split skin graft outcome.

    Science.gov (United States)

    Luczak, Bernard; Ha, Jennifer; Gurfinkel, Reuven

    2012-02-01

    There is an increasing trend towards early mobilisation post-split skin grafting of the lower limbs. This study was performed to determine if early mobilisation impacts negatively on graft healing and patient morbidity. A retrospective review of 48 cases of lower limb split skin grafts performed by the plastic surgery department at Royal Perth Hospital was undertaken. Patients were stratified into early and late mobilisation groups. No difference in outcome was identified with early mobilisation, but an increased rate of deconditioning with increased length of stay was present with late mobilisation. These results suggest that early mobilisation post-split skin grafting of the lower limb is beneficial to patient care and is associated with lower morbidity. © 2011 The Authors. Australasian Journal of Dermatology © 2011 The Australasian College of Dermatologists.

  4. 49 CFR 591.6 - Documents accompanying declarations.

    Science.gov (United States)

    2010-10-01

    ... SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) IMPORTATION OF VEHICLES AND EQUIPMENT SUBJECT TO FEDERAL SAFETY, BUMPER AND THEFT PREVENTION STANDARDS § 591.6 Documents accompanying... be accompanied by a statement substantiating that the vehicle was not manufactured for use on the...

  5. Application of advanced statistical methods in assessment of the late phase of a nuclear accident

    International Nuclear Information System (INIS)

    Hofman, R.

    2008-01-01

    The paper presents a new methodology for improving of estimates of radiological situation on terrain in the late phase of a nuclear accident. Methods of Bayesian filtering are applied to the problem. The estimates are based on combination of modeled and measured data provided by responsible authorities. Exploiting information on uncertainty of both the data sources, we are able to produce improved estimate of the true situation on terrain. We also attempt to account for model error, which is unknown and plays crucial role in accuracy of the estimates. The main contribution of this paper is application of an approach based on advanced statistical methods, which allows for estimating of model error covariance structure upon measurements. Model error is estimated on basis of measured-minus-observed residuals evaluated upon measured and modeled values. The methodology is demonstrated on a sample scenario with simulated measurements. (authors)

  6. Application of advanced statistical methods in assessment of the late phase of a nuclear accident

    International Nuclear Information System (INIS)

    Hofman, R.

    2009-01-01

    The paper presents a new methodology for improving of estimates of radiological situation on terrain in the late phase of a nuclear accident. Methods of Bayesian filtering are applied to the problem. The estimates are based on combination of modeled and measured data provided by responsible authorities. Exploiting information on uncertainty of both the data sources, we are able to produce improved estimate of the true situation on terrain. We also attempt to account for model error, which is unknown and plays crucial role in accuracy of the estimates. The main contribution of this paper is application of an approach based on advanced statistical methods, which allows for estimating of model error covariance structure upon measurements. Model error is estimated on basis of measured-minus-observed residuals evaluated upon measured and modeled values. The methodology is demonstrated on a sample scenario with simulated measurements. (authors)

  7. Plastic Surgery

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Plastic Surgery KidsHealth / For Teens / Plastic Surgery What's in ... her forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word " ...

  8. Severe plastic deformation of copper and Al-Cu alloy using multiple channel-die compression

    International Nuclear Information System (INIS)

    Parimi, A.K.; Robi, P.S.; Dwivedy, S.K.

    2011-01-01

    Research highlights: → SPD of copper and Al-Cu alloy by multiple channel-die compression tests.→ Extensive grain refinement resulting in nano-sized grains after SPD. → Investigation of micro-structure using optical microscope and SEM. → Shear band formation as the failure mechanism in the two phase Al-Cu alloy. → Difficulty in obtaining SPD for Al-Cu alloy in this method. -- Abstract: Severe plastic deformation studies of copper and Al-Cu alloy by multiple channel-die compression tests were investigated. The materials were tested under plane strain condition by maintaining a constant strain rate of 0.001/s. Extensive grain refinement was observed resulting in nano-sized grains after severe plastic deformation with concomitant increase in flow stress and hardness. The microstructural investigation of the severely deformed materials was investigated using optical microscope and scanning electron microscope. Shear band formation was identified as the failure mechanism in the two phase Al-Cu alloy. The results indicate difficulty in obtaining severe plastic deformation for alloys having two phase micro-structure.

  9. Beyond phthalates: Gas phase concentrations and modeled gas/particle distribution of modern plasticizers

    Energy Technology Data Exchange (ETDEWEB)

    Schossler, Patricia [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Institute of Environmental and Sustainable Chemistry, Technische Universitaet Braunschweig, Hagenring 30, D-38106 Braunschweig (Germany); Schripp, Tobias, E-mail: tobias.schripp@wki.fraunhofer.de [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Salthammer, Tunga [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54E, D-38108 Braunschweig (Germany); Bahadir, Muefit [Institute of Environmental and Sustainable Chemistry, Technische Universitaet Braunschweig, Hagenring 30, D-38106 Braunschweig (Germany)

    2011-09-01

    The ongoing health debate about polymer plasticizers based on the esters of phthalic acid, especially di(2-ethylhexyl) phthalate (DEHP), has caused a trend towards using phthalates of lower volatility such as diisononyl phthalate (DINP) and towards other acid esters, such as adipates, terephthalates, citrates, etc. Probably the most important of these so-called 'alternative' plasticizers is diisononyl cyclohexane-1,2-dicarboxylate (DINCH). In the indoor environment, the continuously growing market share of this compound since its launch in 2002 is inter alia apparent from the increasing concentration of DINCH in settled house dust. From the epidemiological point of view there is considerable interest in identifying how semi-volatile organic compounds (SVOCs) distribute in the indoor environment, especially in air, airborne particles and sedimented house dust. This, however, requires reliable experimental concentration data for the different media and good measurements or estimates of their physical and chemical properties. This paper reports on air concentrations for DINP, DINCH, diisobutyl phthalate (DIBP), diisobutyl adipate (DIBA), diisobutyl succinate (DIBS) and diisobutyl glutarate (DIBG) from emission studies in the Field and Laboratory Emission Cell (FLEC). For DINP and DINCH it took about 50 days to reach the steady-state value: for four months no decay in the concentration could be observed. Moreover, vapor pressures p{sub 0} and octanol-air partitioning coefficients K{sub OA} were obtained for 37 phthalate and non-phthalate plasticizers from two different algorithms: EPI Suite and SPARC. It is shown that calculated gas/particle partition coefficients K{sub p} and fractions can widely differ due to the uncertainty in the predicted p{sub 0} and K{sub OA} values. For most of the investigated compounds reliable experimental vapor pressures are not available. Rough estimates can be obtained from the measured emission rate of the pure compound in a

  10. Plastic dosimeter

    International Nuclear Information System (INIS)

    Nagai, Shiro; Matsuda, Kohji.

    1988-01-01

    The report outlines major features and applications of plastic dosimeters. Some plastic dosimeters, including the CTA and PVC types, detect the response of the plastic material itself to radiations while others, such as pigment-added plastic dosimeters, contain additives as radiation detecting material. Most of these dosimeters make use of color centers produced in the dosimeter by radiations. The PMMA dosimeter is widely used in the field of radiation sterilization of food, feed and medical apparatus. The blue cellophane dosimeter is easy to handle if calibrated appropriately. The rad-color dosimeter serves to determine whether products have been irradiated appropriately. The CTA dosimeter has better damp proofing properties than the blue cellophane type. The pigment-added plastic dosimeter consists of a resin such as nylon, CTA or PVC that contains a dye. Some other plastic dosimeters are also described briefly. Though having many advantages, these plastic dosimeter have disadvantages as well. Some of their major disadvantages, including fading as well as large dependence on dose, temperature, humidity and anviroment, are discussed. (Nogami, K.)

  11. Multidimensional Analysis of Direct-Drive Plastic-Shell Implosions on OMEGA

    Science.gov (United States)

    Radha, P. B.

    2004-11-01

    Direct-drive implosions of plastic shells with the OMEGA laser are used as energy-scaled warm surrogates for ignition cryogenic targets designed for use on the National Ignition Facility. Plastic targets involve varying shell thickness (15 to 33 μm), fill pressures (3 to 15 atm), and shell adiabats. The multidimensional hydrodynamics code DRACO is used to evaluate the effects of capsule-surface roughness and illumination nonuniformities on target performance. These simulations indicate that shell stability during the acceleration phase plays a critical role in determining fusion yields. For shells that are thick enough to survive the Rayleigh--Taylor growth, target yields are significantly reduced by growth of the long (ℓ surrogacy between these plastic-shell implosions and the cryogenic ignition designs.

  12. Differences in grip force control between young and late middle-aged adults.

    Science.gov (United States)

    Zheng, Lianrong; Li, Kunyang; Wang, Qian; Chen, Wenhui; Song, Rong; Liu, Guanzheng

    2017-09-01

    Grip force control is a crucial function for human to guarantee the quality of life. To examine the effects of age on grip force control, 10 young adults and 11 late middle-aged adults participated in visually guided tracking tasks using different target force levels (25, 50, and 75% of the subject's maximal grip force). Multiple measures were used to evaluate the tracking performance during force rising phase and force maintenance phase. The measurements include the rise time, fuzzy entropy, mean force percentage, coefficient of variation, and target deviation ratio. The results show that the maximal grip force was significantly lower in the late middle-aged adults than in the young adults. The time of rising phase was systematically longer among late middle-aged adults. The fuzzy entropy is a useful indicator for quantitating the force variability of the grip force signal at higher force levels. These results suggest that the late middle-aged adults applied a compensatory strategy that allow allows for sufficient time to reach the required grip force and reduce the impact of the early and subtle degenerative changes in hand motor function.

  13. Ophthalmic manifestations of methylmalonic aciduria accompanied with homocystinuria

    Directory of Open Access Journals (Sweden)

    Qiu-Jing Huang

    2015-12-01

    Full Text Available Methylmalonicaciduia(MMAaccompanied with homocystinuria is a rare autosomal-recessive with congenital metabolic disorder of Vitamin B12. There are three subtypes, cblC, cblD, cblF, in which cblC is the most common one. The diagnostic tests are tandem mass spectrometry and gas chromatography-mass spectrometry. Tests for activity of enzyme in fibroblasts from skin, complementary assay and genetic analysis can be used to make the subtype clear. Early-onset patients, defined by onset of symptoms before the age of 1 year, may have severe ocular involvement, including visual loss, nystagmus, strabismus, retinopathy, maculopathy, optic atrophy, abnormal electroretinography. Late-onset patients, defined by onset of symptoms after the age of 4 year, rarely have ocular manifestations. The pathogenesis of the ophthalmic symptoms may be related to the high level of homocystine, oxidative stress and the abnormal development of nervous systems. The treatment for MMA accompanied with homocystinuria is mostly symptomatic based. Ophthalmic treatment is limited. Early supplement of methionine,GSH or other antioxidants may be helpful for retinopathy. There is no standard ophthalmological examination for those patients in China. It is critical to set up inter-departmental cooperation and early stage examination for the treatments and outcomes of the patients.

  14. A multi-scale model for structure-property relations of materials exhibiting martensite transformation plasticity

    NARCIS (Netherlands)

    Kouznetsova, V.; Balmachnov, A.; Geers, M.G.D.

    2009-01-01

    The remarkable mechanical properties of many advanced steels, e.g. metastable austenitic stainless steels, are related to their complex microstructural behaviour, resulting from the interaction between plastic deformation of the phases and the austenite to martensite phase transformation during

  15. Evolution of swelling pressure of cohesive-frictional, rough and elasto-plastic granulates

    OpenAIRE

    Luding, Stefan; Bauer, Erich; Jiang, Mingjing; Liu, Fang; Bolton, Malcolm

    2010-01-01

    The subject of this study is the modeling of the evolution of the swell-ing pressure of granulates with cohesive-frictional, rough and elasto-plastic “mi-croscopic” contact properties. The spherical particles are randomly arranged in a periodic cubic space with a fixed volume so that an increase of the particle size – i.e. swelling that can be caused by intake of some fluid – is accompanied by a de-crease of the void space. An analytical function is proposed that properly de-scribes the (macr...

  16. Plasticity and Convergence in the Evolution of Short-Necked Plesiosaurs.

    Science.gov (United States)

    Fischer, Valentin; Benson, Roger B J; Zverkov, Nikolay G; Soul, Laura C; Arkhangelsky, Maxim S; Lambert, Olivier; Stenshin, Ilya M; Uspensky, Gleb N; Druckenmiller, Patrick S

    2017-06-05

    Plesiosaurs were the longest-surviving group of secondarily marine tetrapods, comparable in diversity to today's cetaceans. During their long evolutionary history, which spanned the Jurassic and the Cretaceous (201 to 66 Ma), plesiosaurs repeatedly evolved long- and short-necked body plans [1, 2]. Despite this postcranial plasticity, short-necked plesiosaur clades have traditionally been regarded as being highly constrained to persistent and clearly distinct ecological niches: advanced members of Pliosauridae (ranging from the Middle Jurassic to the early Late Cretaceous) have been characterized as apex predators [2-5], whereas members of the distantly related clade Polycotylidae (middle to Late Cretaceous) were thought to have been fast-swimming piscivores [1, 5-7]. We report a new, highly unusual pliosaurid from the Early Cretaceous of Russia that shows close convergence with the cranial structure of polycotylids: Luskhan itilensis gen. et sp. nov. Using novel cladistic and ecomorphological data, we show that pliosaurids iteratively evolved polycotylid-like cranial morphologies from the Early Jurassic until the Early Cretaceous. This underscores the ecological diversity of derived pliosaurids and reveals a more complex evolutionary history than their iconic representation as gigantic apex predators of Mesozoic marine ecosystems suggests. Collectively, these data demonstrate an even higher degree of morphological plasticity and convergence in the evolution of plesiosaurs than previously thought and suggest the existence of an optimal ecomorphology for short-necked piscivorous plesiosaurs through time and across phylogeny. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 9 CFR 93.409 - Articles accompanying ruminants.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Articles accompanying ruminants. 93.409 Section 93.409 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT...; REQUIREMENTS FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Ruminants § 93.409 Articles accompanying ruminants...

  18. plastic waste recycling

    African Journals Online (AJOL)

    Dr Ahmed

    incinerators is increasing around the world. Discarded plastic products ... Agency (EPA) estimated that the amount of plastics throw away is. 50 % greater in the ... The waste plastics were identified using the Society of the Plastic. Industry (SPI) ...

  19. 16 CFR 1500.125 - Labeling requirements for accompanying literature.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Labeling requirements for accompanying literature. 1500.125 Section 1500.125 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL... REGULATIONS § 1500.125 Labeling requirements for accompanying literature. When any accompanying literature...

  20. Optical security features for plastic card documents

    Science.gov (United States)

    Hossick Schott, Joachim

    1998-04-01

    Print-on-demand is currently a major trend in the production of paper based documents. This fully digital production philosophy will likely have ramifications also for the secure identification document market. Here, plastic cards increasingly replace traditionally paper based security sensitive documents such as drivers licenses and passports. The information content of plastic cards can be made highly secure by using chip cards. However, printed and other optical security features will continue to play an important role, both for machine readable and visual inspection. Therefore, on-demand high resolution print technologies, laser engraving, luminescent pigments and laminated features such as holograms, kinegrams or phase gratings will have to be considered for the production of secure identification documents. Very important are also basic optical, surface and material durability properties of the laminates as well as the strength and nature of the adhesion between the layers. This presentation will address some of the specific problems encountered when optical security features such as high resolution printing and laser engraving are to be integrated in the on-demand production of secure plastic card identification documents.

  1. 9 CFR 93.508 - Articles accompanying swine.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Articles accompanying swine. 93.508 Section 93.508 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Swine § 93.508 Articles accompanying swine. No litter...

  2. Direct liquefaction of plastics and coprocessing of coal with plastics

    Energy Technology Data Exchange (ETDEWEB)

    Huffman, G.P.; Feng, Z.; Mahajan, V. [Univ. of Kentucky, Lexington, KY (United States)

    1995-12-31

    The objectives of this work were to optimize reaction conditions for the direct liquefaction of waste plastics and the coprocessing of coal with waste plastics. In previous work, the direct liquefaction of medium and high density polyethylene (PE), polypropylene (PPE), poly(ethylene terephthalate) (PET), and a mixed plastic waste, and the coliquefaction of these plastics with coals of three different ranks was studied. The results established that a solid acid catalyst (HZSM-5 zeolite) was highly active for the liquefaction of the plastics alone, typically giving oil yields of 80-95% and total conversions of 90-100% at temperatures of 430-450 {degrees}C. In the coliquefaction experiments, 50:50 mixtures of plastic and coal were used with a tetralin solvent (tetralin:solid = 3:2). Using approximately 1% of the HZSM-5 catalyst and a nanoscale iron catalyst, oil yields of 50-70% and total conversion of 80-90% were typical. In the current year, further investigations were conducted of the liquefaction of PE, PPE, and a commingled waste plastic obtained from the American Plastics Council (APC), and the coprocessing of PE, PPE and the APC plastic with Black Thunder subbituminous coal. Several different catalysts were used in these studies.

  3. Late Quaternary landscape development at the margin of the Pomeranian phase (MIS 2) near Lake Wygonin (Northern Poland)

    Science.gov (United States)

    Hirsch, Florian; Schneider, Anna; Nicolay, Alexander; Błaszkiewicz, Mirosław; Kordowski, Jarosław; Noryskiewicz, Agnieszka M.; Tyszkowski, Sebastian; Raab, Alexandra; Raab, Thomas

    2015-04-01

    In Central Europe, Late Quaternary landscapes experienced multiple phases of geomorphologic activity. In this study,we used a combined geomorphological, pedological, sedimentological and palynological approach to characterize landscape development after the Last Glacial Maximum (LGM) near Lake Wygonin in Northern Poland. The pedostratigraphical findings from soil pits and drillings were extrapolated using ground-penetrating radar (GPR) and electric resistivity tomography (ERT). During the Pomeranian phase, glacial and fluvioglacial processes dominated the landscape near Lake Wygonin. At the end of the glacial period, periglacial processes became relevant and caused the formation of ventifacts and coversands containing coated sand grains. At approximately 15,290-14,800 cal yr BP, a small pond formed in a kettle hole (profile BWI2). The lacustrine sediments lack eolian sand components and therefore indicate the decline of eolian processes during that time. The increase of Juniperus and rock-rose (Helianthemum) in the pollen diagram is a prominent marker of the Younger Dryas. At the end of the Younger Dryas, a partial reshaping of the landscape is indicated by abundant charcoal fragments in disturbed lake sediments. No geomorphologic activity since the beginning of the Holocene is documented in the terrestrial and wetland archives. The anthropogenic impact is reflected in the pollen diagram by the occurrence of rye pollen grains (Cerealia type, Secale cereale) and translocated soil sediments dated to 1560-1410 cal yr BP, proving agricultural use of the immediate vicinity. With the onset of land use, gully incision and the accumulation of colluvial fans reshaped the landscape locally. Since 540-460 cal yr BP, further gully incision in the steep forest tracks has been associated with the intensification of forestry. Outside of the gully catchments, the weakly podzolized Rubic Brunic Arenosols show no features of Holocene soil erosion. Reprinted from CATENA, Volume 124

  4. 9 CFR 93.307 - Articles accompanying horses.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Articles accompanying horses. 93.307... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Horses § 93.307 Articles accompanying horses. No..., blankets, or other things used for or about horses governed by the regulations this part, shall be landed...

  5. Plasticity of maritime pine (Pinus pinaster) wood-forming tissues during a growing season.

    Science.gov (United States)

    Paiva, J A P; Garnier-Géré, P H; Rodrigues, J C; Alves, A; Santos, S; Graça, J; Le Provost, G; Chaumeil, G; Da Silva-Perez, D; Bosc, A; Fevereiro, P; Plomion, C

    2008-01-01

    The seasonal effect is the most significant external source of variation affecting vascular cambial activity and the development of newly divided cells, and hence wood properties. Here, the effect of edapho-climatic conditions on the phenotypic and molecular plasticity of differentiating secondary xylem during a growing season was investigated. Wood-forming tissues of maritime pine (Pinus pinaster) were collected from the beginning to the end of the growing season in 2003. Data from examination of fibre morphology, Fourier-transform infrared spectroscopy (FTIR), analytical pyrolysis, and gas chromatography/mass spectrometry (GC/MS) were combined to characterize the samples. Strong variation was observed in response to changes in edapho-climatic conditions. A genomic approach was used to identify genes differentially expressed during this growing season. Out of 3512 studied genes, 19% showed a significant seasonal effect. These genes were clustered into five distinct groups, the largest two representing genes over-expressed in the early- or late-wood-forming tissues, respectively. The other three clusters were characterized by responses to specific edapho-climatic conditions. This work provides new insights into the plasticity of the molecular machinery involved in wood formation, and reveals candidate genes potentially responsible for the phenotypic differences found between early- and late-wood.

  6. Anisotropic molecular reorientations of quinuclidine in its plastic solid phase: 1H and 14N NMR relaxation study

    International Nuclear Information System (INIS)

    Brot, C.; Virlet, J.

    1979-01-01

    14 N and 1 H NMR relaxation times have been measured in quinuclidine in its plastic phase. These measurements rule out isotropic motion. Correlation times for several anisotropic reorientational models are calculated from these NMR data. The best agreement with the values calculated from neutron scattering experiments (preceding paper) is obtained for a model where the molecules reorient by +-90 0 jumps about the crystallographic C 4 axes with a residence time of (22.2+-2).10 -12 s, and by +-120 0 jumps about the molecular C 3 axes with a residence of (5.25+-2.8).10 -12 s, at room temperature. The activation enthalpy is 15.3 kJ.mol. -1 for the +-90 0 jumps, and higher for the +-120 0 jumps. Translational correlation times have also been measured at high temperature, below the melting point

  7. Late-onset anaphylaxis due to poly (γ-glutamic acid) in the soup of commercial cold Chinese noodles in a patient with allergy to fermented soybeans (natto).

    Science.gov (United States)

    Inomata, Naoko; Chin, Keishi; Nagashima, Mayumi; Ikezawa, Zenro

    2011-09-01

    Fermented soybeans (natto) have been reported to induce IgE-mediated, late-onset anaphylaxis without early-phase responses. However, the relevant allergens of natto allergy have never been identified. A 38-year-old man developed an anaphylactic reaction accompanied by flashing, generalized urticaria, conjunctival redness, and dyspnea 3 hours after ingestion of commercial cold Chinese noodles. He had avoided natto for the past year due to developing several anaphylactic reactions half a day after natto ingestion. The results of skin prick tests (SPTs) were strongly positive for natto and the soup of cold Chinese noodles. Furthermore, SPTs showed positive for poly (γ-glutamic acid) (PGA), which is a major constituent of natto mucilage, alone among all the ingredients of the cold Chinese noodle soup. Therefore, he was diagnosed with late-onset anaphylaxis to PGA contained in natto and the cold Chinese noodle soup. These results indicated that in the present case, the relevant allergen of late-onset anaphylaxis may have been PGA in all episodes and that the patient had been sensitized by PGA through natto ingestion. PGA is produced by Bacillus subtilis during fermentation and is a high-molecular, biodegradable polymer. The late onset is therefore, hypothesized to be due to a delayed absorption of PGA, as PGA biodegrades to peptides sufficiently small to be absorbed in the bowel. PGA has recently been applied to a wide range of fields such as foods, cosmetics, and medicine. Therefore, patients with late-onset anaphylaxis to PGA of natto should avoid not only natto but also other materials containing PGA.

  8. Comprehensive Deformation Analysis of a Newly Designed Ni-Free Duplex Stainless Steel with Enhanced Plasticity by Optimizing Austenite Stability

    DEFF Research Database (Denmark)

    Moallemi, Mohammad; Zarei-Hanzaki, Abbas; Eskandari, Mostafa

    2017-01-01

    A new metastable Ni-free duplex stainless steel has been designed with superior plasticity by optimizing austenite stability using thermodynamic calculations of stacking fault energy and with reference to literature findings. Several characterization methods comprising optical microscopy, magnetic......, including an ultimate tensile strength of ~900 MPa and elongation to fracture of ~94 pct due to the synergistic effects of transformation-induced plasticity and twinning-induced plasticity. The deformation mechanism of austenite is complex and includes deformation banding, strain-induced martensite...... formation, and deformation-induced twinning, while the ferrite phase mainly deforms by dislocation slip. Texture analysis indicates that the Copper and Rotated Brass textures in austenite (FCC phase) and {001}〈110〉 texture in ferrite and martensite (BCC phases) are the main active components during...

  9. Evaluation of a disposable plastic Neubauer counting chamber for semen analysis.

    Science.gov (United States)

    Kirkman-Brown, Jackson; Björndahl, Lars

    2009-02-01

    To evaluate whether disposable plastic counting chambers effectively could replace nondisposable, time-consuming, and potentially dangerous glass hemocytometers. Evaluation of equipment in modern laboratory andrology. Comparison of results obtained with plastic chambers with results obtained with "gold-standard" glass hemocytometer counts. Diagnostic laboratory for andrology. Twenty-one patients undergoing investigation for infertility problems. No interventions with patients; sperm in diluted semen samples were used when patients had allowed the use for research and training. Sperm concentration, difference from results obtained with standard equipment. In the first three experimental series, with use of standard routine phase-contrast microscopy, significantly lower count results were obtained consistently from the plastic chambers than from standard chambers. In the fourth series, with use of specialized equipment, equivalent results were obtained but with a considerably greater time commitment because of difficulties in distinguishing sperm adjacent to the gridlines in the plastic chambers. The plastic disposable chamber type was not suitable for routine semen analysis because results are variable depending on the microscope used, and increased time is necessary to do the assessment accurately.

  10. Relationship between ADAMTS13 activity, von Willebrand factor antigen levels and platelet function in the early and late phases after TIA or ischaemic stroke.

    Science.gov (United States)

    McCabe, Dominick J H; Murphy, Stephen J X; Starke, Richard; Harrison, Paul; Brown, Martin M; Sidhu, Paul S; Mackie, Ian J; Scully, Marie; Machin, Samuel J

    2015-01-15

    Reduced ADAMTS13 activity is seen in thrombotic thrombocytopenic purpura (TTP), and may lead to accumulation of prothrombotic ultra-large von Willebrand factor (ULVWF) multimers in vivo. ADAMTS13 activity and its relationship with VWF antigen (VWF:Ag) levels and platelet function in 'non-TTP related' TIA or ischaemic stroke has not been comprehensively studied. In this prospective pilot observational analytical case-control study, ADAMTS13 activity and VWF:Ag levels were quantified in platelet poor plasma in 53 patients in the early phase (≤ 4 weeks) and 34 of these patients in the late phase (≥ 3 months) after TIA or ischaemic stroke on aspirin. Data were compared with those from 22 controls not on aspirin. The impact of ADAMTS13 on platelet function in whole blood was quantified by measuring Collagen-ADP (C-ADP) and Collagen-Epinephrine closure times on a platelet function analyser (PFA-100(®)). Median ADAMTS13 activity was significantly reduced in the early phase (71.96% vs. 95.5%, P TIA or stroke compared with controls (86.3% vs. 95.5%, P=0.19). There was a significant inverse relationship between ADAMTS13 activity and VWF:Ag levels in the early phase (r=-0.31; P=0.024), but not in the late phase after TIA or stroke (P=0.74). There was a positive correlation between ADAMTS13 activity and C-ADP closure times in early phase patients only, likely mediated via VWF:Ag levels. ADAMTS13 activity is reduced and VWF:Ag expression is increased within 4 weeks of TIA or ischaemic stroke onset, and can promote enhanced platelet adhesion and aggregation in response to stimulation with collagen and ADP via VWF-mediated pathways. These data improve our understanding of the dynamic haemostatic and thrombotic profiles of ischaemic cerebrovascular disease (CVD) patients, and are important in view of the potential future role that ADAMTS13 may have to play as an anti-thrombotic agent in CVD. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like...

  12. Investigation into diffusion induced plastic deformation behavior in hollow lithium ion battery electrode revealed by analytical model and atomistic simulation

    International Nuclear Information System (INIS)

    Li, Jia; Fang, Qihong; Wu, Hong; Liu, Youwen; Wen, Pihua

    2015-01-01

    Highlights: • Diffusion induced stress is established. • Yield stress is dependent upon concentration. • Plastic deformation induced stress lowers tensile stress. • Plastic deformation suppresses crack nucleation. • Plastic deformation occurs not only at lithiated phase but also at electrode interior. - Abstract: This paper is theoretically suggested to describe diffusion induced stress in the elastoplastic hollow spherical silicon electrode for plastic deformation using both analytical model and molecular simulation. Based on the plastic deformation and the yield criterion, we develop this model accounting for the lithium-ion diffusion effect in hollow electrode, focusing on the concentration and stress distributions undergoing lithium-ion insertion. The results show that the two ways, applied compressive stress to inner surface or limited inner surface with higher concentration using biological membranes maintaining concentration difference, lead to the compressive stress induced by the lithium-ion diffusion effect. Hollow spherical electrode reduces effectively diffusion induced stress through controlling and tuning electrode parameters to obtain the reasonably low yield strength. According to MD simulations, plastic deformation phenomenon not only occurs at interface layer of lithiated phase, but also penetrates at electrode interior owning to confinement imposed by lithiated phase. These criteria that radial and hoop stresses reduce dramatically when plastic deformation occurs near the end faces of hollow electrode, may help guide development of new materials for lithium-ion batteries with enhanced mechanical durability, by means of reasonable designing yield strength to maintain mechanical stress below fracture strength, thereby increasing battery life.

  13. Effect of different levels of methionine, protein and tallow on the productive performance and egg quality of laying hens in the late-phase production

    Directory of Open Access Journals (Sweden)

    H Nassiri Moghaddam

    2012-06-01

    Full Text Available An experiment was conducted to determine the effects of different levels of methionine, protein and tallow on productive performance and egg quality of laying hens in the late phase of production. A completely randomized design with a 3×2×2 factorial arrangement, with three levels (0.34, 0.31, and 0.27% of methionine (MET, two levels (12.8 and 14.7% of protein (PRO and two levels (1 and 3% of tallow (TAL with constant level of linoleic acid (1.55 ± 0.02%, was used. A number of 144 Hi-Line W-36 layers from 70 to 76 wk of age was randomly distributed into 12 treatment groups with 4 replicates of 3 hens each. Egg production and egg weight were daily recorded and feed intake and egg quality traits were recorded every 2 wk. There was a significant interaction between PRO levels and TAL for egg weight. Low levels of TAL and PRO decreased egg weight throughout the experiment. High levels of MET and TAL with concomitant reduced PRO, increased eggshell thickness, and a significant interaction between levels of MET, PRO and TAL was observed during the experiment (70 to 76 wk. Low level of protein (12.8% significantly decreased albumen weight in the third 2-wk period. Yolk color increased when hens were fed low levels of PRO and TAL. Results of this experiment indicated that the simultaneous reduction of dietary PRO and MET in diets of Hi-Line W-36 laying hens in the late phase of production, reduced egg weight (P<0.05. Productive performance and egg quality were not affected by 12 and 20% reduction of PRO and MET, respectively. It seems that decreasing the levels of MET and PRO to lower than the recommended values can decrease egg weight without negative effects on productive performance and egg quality of laying hens in the late phase of production.

  14. "Plastic" solar cells: self-assembly of bulk heterojunction nanomaterials by spontaneous phase separation.

    Science.gov (United States)

    Peet, Jeffrey; Heeger, Alan J; Bazan, Guillermo C

    2009-11-17

    As the global demand for low-cost renewable energy sources intensifies, interest in new routes for converting solar energy to electricity is rapidly increasing. Although photovoltaic cells have been commercially available for more than 50 years, only 0.1% of the total electricity generated in the United States comes directly from sunlight. The earliest commercial solar technology remains the basis for the most prevalent devices in current use, namely, highly-ordered crystalline, inorganic solar cells, commonly referred to as silicon cells. Another class of solar cells that has recently inspired significant academic and industrial excitement is the bulk heterojunction (BHJ) "plastic" solar cell. Research by a rapidly growing community of scientists across the globe is generating a steady stream of new insights into the fundamental physics, the materials design and synthesis, the film processing and morphology, and the device science and architecture of BHJ technology. Future progress in the fabrication of high-performance BHJ cells will depend on our ability to combine aspects of synthetic and physical chemistry, condensed matter physics, and materials science. In this Account, we use a combination of characterization tools to tie together recent advances in BHJ morphology characterization, device photophysics, and thin-film solution processing, illustrating how to identify the limiting factors in solar cell performance. We also highlight how new processing methods, which control both the BHJ phase separation and the internal order of the components, can be implemented to increase the power conversion efficiency (PCE). The failure of many innovative materials to achieve high performance in BHJ solar cell devices has been blamed on "poor morphology" without significant characterization of either the structure of the phase-separated morphology or the nature of the charge carrier recombination. We demonstrate how properly controlling the "nanomorphology", which is

  15. Hardening of Fe-Cr-Mn steels cold plastic working

    International Nuclear Information System (INIS)

    Malinov, L.S.; Konop-Lyashko, V.I.; Nikoporets, N.M.

    1983-01-01

    The dependence is established between the level of proper-- ties obtained after cold plastic working and development of martensite transformations when loading in Fe-Cr-Mn steels containing 0.1-0.5% C, 13% Cr, 8-12% Mn, as well as in a number of complex alloyed steels. It is shown that the highest level of mechanical properties can be obtained after cold plastic working only in steels with definite austenite stability. Cold plastic working can both activize and stabilize austenite relatively to martensite formation during loading. The first thing is found when under the effect of preliminary cold working dislocation splitting takes place, as well as the formation of a small amount of E-phase and martensite. The second thing manifests itself when under the effect of cold working performed above Md (Md<20 deg C) cell dislocation structure is formed and dislocation pinning takes place

  16. Constitutive modeling of multiphase materials including phase transformations

    NARCIS (Netherlands)

    Perdahcioglu, Emin Semih; Geijselaers, Hubertus J.M.; Khan, A.S.; Meredith, C; Farrokh, B

    2011-01-01

    A constitutive model is developed for materials involving two or more different phases in their microstructure such as DP (Dual Phase) or TRIP (TRansformation Induced Plasticity) steels. Homogenization of the response of the phases is achieved by the Mean-Field method. One of the phases in TRIP

  17. Thermal expansion accompanying the glass-liquid transition and crystallization

    Directory of Open Access Journals (Sweden)

    M. Q. Jiang

    2015-12-01

    Full Text Available We report the linear thermal expansion behaviors of a Zr-based (Vitreloy 1 bulk metallic glass in its as-cast, annealed and crystallized states. Accompanying the glass-liquid transition, the as-cast Vitreloy 1 shows a continuous decrease in the thermal expansivity, whereas the annealed glass shows a sudden increase. The crystallized Vitreloy 1 exhibits an almost unchanged thermal expansivity prior to its melting. Furthermore, it is demonstrated that the nucleation of crystalline phases can induce a significant thermal shrinkage of the supercooled liquid, but with the growth of these nuclei, the thermal expansion again dominates. These results are explained in the framework of the potential energy landscape, advocating that the configurational and vibrational contributions to the thermal expansion of the glass depend on both, structure and temperature.

  18. Influence of the Martensitic Transformation on the Microscale Plastic Strain Heterogeneities in a Duplex Stainless Steel

    Science.gov (United States)

    Lechartier, Audrey; Martin, Guilhem; Comby, Solène; Roussel-Dherbey, Francine; Deschamps, Alexis; Mantel, Marc; Meyer, Nicolas; Verdier, Marc; Veron, Muriel

    2017-01-01

    The influence of the martensitic transformation on microscale plastic strain heterogeneity of a duplex stainless steel has been investigated. Microscale strain heterogeneities were measured by digital image correlation during an in situ tensile test within the SEM. The martensitic transformation was monitored in situ during tensile testing by high-energy synchrotron X-ray diffraction. A clear correlation is shown between the plasticity-induced transformation of austenite to martensite and the development of plastic strain heterogeneities at the phase level.

  19. Synaptic Tagging, Evaluation of Memories, and the Distal Reward Problem

    Science.gov (United States)

    Papper, Marc; Kempter, Richard; Leibold, Christian

    2011-01-01

    Long-term synaptic plasticity exhibits distinct phases. The synaptic tagging hypothesis suggests an early phase in which synapses are prepared, or "tagged," for protein capture, and a late phase in which those proteins are integrated into the synapses to achieve memory consolidation. The synapse specificity of the tags is consistent with…

  20. Functional genomics of physiological plasticity and local adaptation in killifish.

    Science.gov (United States)

    Whitehead, Andrew; Galvez, Fernando; Zhang, Shujun; Williams, Larissa M; Oleksiak, Marjorie F

    2011-01-01

    Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation.

  1. A comparison of plastic collapse and limit loads for single mitred pipe bends under in-plane bending

    International Nuclear Information System (INIS)

    Neilson, R.; Wood, J.; Hamilton, R.; Li, H.

    2010-01-01

    This paper presents a comparison of the plastic collapse loads from experimental in-plane bending tests on three 90 o single un-reinforced mitred pipe bends, with the results from various 3D solid finite element models. The bending load applied reduced the bend angle and in turn, the resulting cross-sectional ovalisation led to a recognised weakening mechanism. In addition, at maximum load there was a reversal in stiffness, characteristic of buckling. This reversal in stiffness was accompanied by significant ovalisation and plasticity at the mitre intersection. Both the weakening mechanism and the post-buckling behaviour are only observable by testing or by including large displacement effects in the plastic finite element solution. A small displacement limit solution with an elastic-perfectly plastic material model overestimated the collapse load by more than 40% and could not reproduce the buckling behaviour. The plastic collapse finite element solution, with large displacements, produced excellent agreement with the experiment. Sufficient experimental detail is presented for these results to be used as a benchmark for analysts in this area. Given the robustness of non-linear solutions in commercial finite element codes and the ready availability of computing resources, it is argued that pressure vessel code developers should now be recommending large displacement analysis as the default position for limit and plastic collapse analyses, rather than expecting engineers to anticipate weakening mechanisms and related non-linear phenomena.

  2. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

  3. Evaluation of the Levels of phthalate Ester Plasticizers in Surface ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Gas chromatography (GC) coupled with mass ... Key words: phthalates, acid esters, plasticizers, Ethiope River, surface water, pollution ... waste and emissions arising from burning of refuse ... deepest inland waterways in Africa, is known for its ..... carbon nitride nanocomposites for the solid-phase extraction of phthalate ...

  4. Adaptation to an extraordinary environment by evolution of phenotypic plasticity and genetic assimilation.

    Science.gov (United States)

    Lande, Russell

    2009-07-01

    Adaptation to a sudden extreme change in environment, beyond the usual range of background environmental fluctuations, is analysed using a quantitative genetic model of phenotypic plasticity. Generations are discrete, with time lag tau between a critical period for environmental influence on individual development and natural selection on adult phenotypes. The optimum phenotype, and genotypic norms of reaction, are linear functions of the environment. Reaction norm elevation and slope (plasticity) vary among genotypes. Initially, in the average background environment, the character is canalized with minimum genetic and phenotypic variance, and no correlation between reaction norm elevation and slope. The optimal plasticity is proportional to the predictability of environmental fluctuations over time lag tau. During the first generation in the new environment the mean fitness suddenly drops and the mean phenotype jumps towards the new optimum phenotype by plasticity. Subsequent adaptation occurs in two phases. Rapid evolution of increased plasticity allows the mean phenotype to closely approach the new optimum. The new phenotype then undergoes slow genetic assimilation, with reduction in plasticity compensated by genetic evolution of reaction norm elevation in the original environment.

  5. Our plastic age.

    Science.gov (United States)

    Thompson, Richard C; Swan, Shanna H; Moore, Charles J; vom Saal, Frederick S

    2009-07-27

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation.

  6. Our plastic age

    Science.gov (United States)

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation. PMID:19528049

  7. Combined model of strain-induced phase transformation and orthotropic damage in ductile materials at cryogenic temperatures

    CERN Document Server

    Garion, Cedric

    2003-01-01

    Ductile materials (like stainless steel or copper) show at cryogenic temperatures three principal phenomena: serrated yielding (discontinuous in terms of dsigma/depsilon), plastic strain-induced phase transformations and evolution of ductile damage. The present paper deals exclusively with the two latter cases. Thus, it is assumed that the plastic flow is perfectly smooth. Both in the case of damage evolution and for the gamma-alpha prime phase transformation, the principal mechanism is related to the formation of plastic strain fields. In the constitutive modeling of both phenomena, a crucial role is played by the accumulated plastic strain, expressed by the Odqvist parameter p. Following the general trends, both in the literature concerning the phase transformation and the ductile damage, it is assumed that the rate of transformation and the rate of damage are proportional to the accumulated plastic strain rate. The gamma-alpha prime phase transformation converts the initially homogenous material to a two-p...

  8. Gene Expression Patterns Underlying the Reinstatement of Plasticity in the Adult Visual System

    Directory of Open Access Journals (Sweden)

    Ettore Tiraboschi

    2013-01-01

    Full Text Available The nervous system is highly sensitive to experience during early postnatal life, but this phase of heightened plasticity decreases with age. Recent studies have demonstrated that developmental-like plasticity can be reactivated in the visual cortex of adult animals through environmental or pharmacological manipulations. These findings provide a unique opportunity to study the cellular and molecular mechanisms of adult plasticity. Here we used the monocular deprivation paradigm to investigate large-scale gene expression patterns underlying the reinstatement of plasticity produced by fluoxetine in the adult rat visual cortex. We found changes, confirmed with RT-PCRs, in gene expression in different biological themes, such as chromatin structure remodelling, transcription factors, molecules involved in synaptic plasticity, extracellular matrix, and excitatory and inhibitory neurotransmission. Our findings reveal a key role for several molecules such as the metalloproteases Mmp2 and Mmp9 or the glycoprotein Reelin and open up new insights into the mechanisms underlying the reopening of the critical periods in the adult brain.

  9. Impact of Bio-Based Plastics on Current Recycling of Plastics

    Directory of Open Access Journals (Sweden)

    Luc Alaerts

    2018-05-01

    Full Text Available Bio-based plastics are increasingly appearing in a range of consumption products, and after use they often end up in technical recycling chains. Bio-based plastics are different from fossil-based ones and could disturb the current recycling of plastics and hence inhibit the closure of plastic cycles, which is undesirable given the current focus on a transition towards a circular economy. In this paper, this risk has been assessed via three elaborated case studies using data and information retrieved through an extended literature search. No overall risks were revealed for bio-based plastics as a group; rather, every bio-based plastic is to be considered as a potential separate source of contamination in current recycling practices. For PLA (polylactic acid, a severe incompatibility with PET (polyethylene terephthalate recycling is known; hence, future risks are assessed by measuring amounts of PLA ending up in PET waste streams. For PHA (polyhydroxy alkanoate there is no risk currently, but it will be crucial to monitor future application development. For PEF (polyethylene furanoate, a particular approach for contamination-related issues has been included in the upcoming market introduction. With respect to developing policy, it is important that any introduction of novel plastics is well guided from a system perspective and with a particular eye on incompatibilities with current and upcoming practices in the recycling of plastics.

  10. Achieving preferred customer status in the Dutch plastics recycling ...

    African Journals Online (AJOL)

    The aim of this research is to gain insight into the aspects and processes in the Dutch plastic recycling industry which might lead to a preferred customer status and acquiring benefits once the status has been reached. The whole process of reaching preferred customer status goes through various phases in which customer ...

  11. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  12. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  13. In Situ Manufacturing of Plastics and Composites to Support H&R Exploration, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering and BAE Systems propose to develop processes to manufacture plastics and composites for radiation shielding based on In Situ Resources Utilization...

  14. Theory of the axi-symmetric extrusion process of multi-layer materials with a strong plastic nonhomogeneity

    OpenAIRE

    J. Piwnik; A. Patejuk

    2008-01-01

    A novel simplified r hcorctical solution is found lor thc strcss starcs accompanying thc proccss of cxt ri~siono f ma![ i-laycr matcrialsunder rhc conditions af axial symmetry. Thc solution i~ bawd nn ~ h mc n dcl of pcrfcct plastic material satisfying thc Trcsca yicld condition.thc Haar-Karman conditions bcing sntisficd in each layer. Thc laycrs arc chnnctcrizcd by difrercnt yicld limits and stmng plasticnonhomogeneity. In thc ncighhoi~rhoorol f thc interfaces conrinuous variation of rhc yic...

  15. Determination of the single-phase constitutive relations of α/β dual phase TC6 titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ran; Li, Guoju [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials Under Shock and Impact, Beijing 100081 (China); Nie, Zhihua [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Fan, Qunbo, E-mail: fanqunbo@bit.edu.cn [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); National Key Laboratory of Science and Technology on Materials Under Shock and Impact, Beijing 100081 (China)

    2016-10-15

    The constitutive relations of α and β phases in a TC6 titanium alloy were determined by implementing a two-phase elastic-plastic self-consistent (EPSC) framework combined with the evolution of lattice strains; these strains were obtained via in-situ tensile loading synchrotron-based x-ray diffraction experiments. It was found that the {200}{sub β} reflection has the lowest stiffness and load partitions prior to the α phase during the elastic loading stage in this alloy. The simulated parameters including the diffraction elastic constant and initial yield stress of lattice reflections exhibited satisfactory correspondence with the experimental results. Further analysis of the characteristics of the Schmid Factor (SF) distributions of the main slip systems revealed that the elastic-plastic transition process in the α phase occurs over a prolonged period. In contrast, the β phase undergoes a transient process owing to its relatively more concentrated SF frequency distributions, than those of the α phase. In addition, the fitted stress-strain curve of each phase was compared with the measured macro stress-strain curve obtained from the in-situ experiment. It revealed Young's moduli of 110.3 GPa and 104.5 GPa, and yield stresses of 877.8 MPa and 969 MPa, for the α and β phases, respectively.

  16. Late onset MELAS with m.3243A > G mutation and its association with aneurysm formation.

    Science.gov (United States)

    Zhu, Kun; Li, Shuang; Chen, Huan; Wang, Yao; Yu, Miao; Wang, Hongyan; Zhao, Weijie; Cao, Yunpeng

    2017-08-01

    We reported a 53-year-old with late-onset mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) accompanied by aneurysm and large vessel dilations. Most studies have focused on microangiopathy causing stroke-like episodes. We report a case to describe large vessel involvement in clinical considerations, and possible mechanisms of aneurysm formation. We recommended regular angiographic examination for patients with MELAS.

  17. Characterization of plastic blends made from mixed plastics waste of different sources.

    Science.gov (United States)

    Turku, Irina; Kärki, Timo; Rinne, Kimmo; Puurtinen, Ari

    2017-02-01

    This paper studies the recyclability of construction and household plastic waste collected from local landfills. Samples were processed from mixed plastic waste by injection moulding. In addition, blends of pure plastics, polypropylene and polyethylene were processed as a reference set. Reference samples with known plastic ratio were used as the calibration set for quantitative analysis of plastic fractions in recycled blends. The samples were tested for the tensile properties; scanning electron microscope-energy-dispersive X-ray spectroscopy was used for elemental analysis of the blend surfaces and Fourier transform infrared (FTIR) analysis was used for the quantification of plastics contents.

  18. Plastic Change along the Intact Crossed Pathway in Acute Phase of Cerebral Ischemia Revealed by Optical Intrinsic Signal Imaging

    Directory of Open Access Journals (Sweden)

    Xiaoli Guo

    2016-01-01

    Full Text Available The intact crossed pathway via which the contralesional hemisphere responds to the ipsilesional somatosensory input has shown to be affected by unilateral stroke. The aim of this study was to investigate the plasticity of the intact crossed pathway in response to different intensities of stimulation in a rodent photothrombotic stroke model. Using optical intrinsic signal imaging, an overall increase of the contralesional cortical response was observed in the acute phase (≤48 hours after stroke. In particular, the contralesional hyperactivation is more prominent under weak stimulations, while a strong stimulation would even elicit a depressed response. The results suggest a distinct stimulation-response pattern along the intact crossed pathway after stroke. We speculate that the contralesional hyperactivation under weak stimulations was due to the reorganization for compensatory response to the weak ipsilateral somatosensory input.

  19. Side effects and late sequelae of combined irradiation- and chemotherapy of the neurocranium in children with acute lymphoblastic leukaemia

    International Nuclear Information System (INIS)

    Zippel, R.M.

    1978-01-01

    Therapeutical procedures are not only judged according to their efficacy, but also with respect to their affection to the patient. For acute side effects as headaches, nausea, tiredness and fever, which occurred in several children, cranial irradiation and intrathecal MTX injections have to be considered as responsible factors. These accompanying symptoms, for example also alopecia, have to be tolerated with respect to the successful course of phase II, i.e. the prevention of a leukaemic meningo-encephalitis. The somnolence syndrome can be observed also after cerebral irradiation with a different indication; in several patients the occurrence of this syndrome has to be expected. Up to the present no secondary damages caused by this syndrome have been observed. Severe neurologic disorders only rarely appear within the course of the ALL; nevertheless it is necessary to determine at the earliest possible date also more subtle disturbances in the neurologic and psychic development of the children by neurologic examinations, regular ECG registrations, and psychologic tests. A delineation of late damages of ZNS therapy is only possible on the basis of the cerebral post-mortem findings. Since the dose of the brain irradiations of phase II are within the limits of the generally accepted tolerance range, a late necrosis induced by irradiation, has not to be expected. Single cases of leukoencephalopathies are ascribed to the ALL therapy. Growth retardations - which in the most cases are reversible - are found in children treated with ALL therapy; as possibly damaging agent also neurocranial irradiation might be considered as responsible. Regular control examinations of the length show a possibly occuring growth reduction, which should be accessible by hormone therapy if necessary. (orig./MG) [de

  20. Proteomic analysis of oil body membrane proteins accompanying the onset of desiccation phase during sunflower seed development

    Science.gov (United States)

    Thakur, Anita; Bhatla, Satish C

    2015-01-01

    A noteworthy metabolic signature accompanying oil body (OB) biogenesis during oilseed development is associated with the modulation of the oil body membranes proteins. Present work focuses on 2-dimensional polyacrylamide gel electrophoresis (2-D PAGE)-based analysis of the temporal changes in the OB membrane proteins analyzed by LC-MS/MS accompanying the onset of desiccation (20–30 d after anthesis; DAA) in the developing seeds of sunflower (Helianthus annuus L.). Protein spots unique to 20–30 DAA stages were picked up from 2-D gels for identification and the identified proteins were categorized into 7 functional classes. These include proteins involved in energy metabolism, reactive oxygen scavenging, proteolysis and protein turnover, signaling, oleosin and oil body biogenesis-associated proteins, desiccation and cytoskeleton. At 30 DAA stage, exclusive expressions of enzymes belonging to energy metabolism, desiccation and cytoskeleton were evident which indicated an increase in the metabolic and enzymatic activity in the cells at this stage of seed development (seed filling). Increased expression of cruciferina-like protein and dehydrin at 30 DAA stage marks the onset of desiccation. The data has been analyzed and discussed to highlight desiccation stage-associated metabolic events during oilseed development. PMID:26786011

  1. The Prevalence of Cosmetic Facial Plastic Procedures among Facial Plastic Surgeons.

    Science.gov (United States)

    Moayer, Roxana; Sand, Jordan P; Han, Albert; Nabili, Vishad; Keller, Gregory S

    2018-04-01

    This is the first study to report on the prevalence of cosmetic facial plastic surgery use among facial plastic surgeons. The aim of this study is to determine the frequency with which facial plastic surgeons have cosmetic procedures themselves. A secondary aim is to determine whether trends in usage of cosmetic facial procedures among facial plastic surgeons are similar to that of nonsurgeons. The study design was an anonymous, five-question, Internet survey distributed via email set in a single academic institution. Board-certified members of the American Academy of Facial Plastic and Reconstructive Surgery (AAFPRS) were included in this study. Self-reported history of cosmetic facial plastic surgery or minimally invasive procedures were recorded. The survey also queried participants for demographic data. A total of 216 members of the AAFPRS responded to the questionnaire. Ninety percent of respondents were male ( n  = 192) and 10.3% were female ( n  = 22). Thirty-three percent of respondents were aged 31 to 40 years ( n  = 70), 25% were aged 41 to 50 years ( n  = 53), 21.4% were aged 51 to 60 years ( n  = 46), and 20.5% were older than 60 years ( n  = 44). Thirty-six percent of respondents had a surgical cosmetic facial procedure and 75% has at least one minimally invasive cosmetic facial procedure. Facial plastic surgeons are frequent users of cosmetic facial plastic surgery. This finding may be due to access, knowledge base, values, or attitudes. By better understanding surgeon attitudes toward facial plastic surgery, we can improve communication with patients and delivery of care. This study is a first step in understanding use of facial plastic procedures among facial plastic surgeons. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  2. Finite element evaluation of elasto-plastic accommodation energies during solid state transformations: Coherent, spherical precipitate in finite matrix

    International Nuclear Information System (INIS)

    Sen, S.; Balasubramaniam, R.; Sethuraman, R.

    1996-01-01

    The molar volume difference between the matrix and the precipitate phases in the case of solid state phase transformations results in the creation of stain energy in the system due to the misfit strains. A finite element model based on the initial strain approach is proposed to evaluate elasto-plastic accommodation energies during solid state transformation. The three-dimensional axisymmetric model has been used to evaluate energies as a function of transformation for α-β hydrogen transformations in the Nb-H system. The transformation has been analyzed for the cases of transformation progressing both from the center to surface and from the surface to center of the system. The effect of plastic deformation has been introduced to make the model realistic, specifically to the Nb-NbH phase transformation which involves a 4% linear misfit strain. It has been observed that plastic deformation reduces the strain energies compared to the linear elastic analysis

  3. Recycling of plastic waste: Presence of phthalates in plastics from households and industry.

    Science.gov (United States)

    Pivnenko, K; Eriksen, M K; Martín-Fernández, J A; Eriksson, E; Astrup, T F

    2016-08-01

    Plastics recycling has the potential to substitute virgin plastics partially as a source of raw materials in plastic product manufacturing. Plastic as a material may contain a variety of chemicals, some potentially hazardous. Phthalates, for instance, are a group of chemicals produced in large volumes and are commonly used as plasticisers in plastics manufacturing. Potential impacts on human health require restricted use in selected applications and a need for the closer monitoring of potential sources of human exposure. Although the presence of phthalates in a variety of plastics has been recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP had the highest frequency of detection in the samples analysed, with 360μg/g, 460μg/g and 2700μg/g as the maximum measured concentrations, respectively. Among other, statistical analysis of the analytical results suggested that phthalates were potentially added in the later stages of plastic product manufacturing (labelling, gluing, etc.) and were not removed following recycling of household waste plastics. Furthermore, DEHP was identified as a potential indicator for phthalate contamination of plastics. Close monitoring of plastics intended for phthalates-sensitive applications is recommended if recycled plastics are to be used as raw material in production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Recycling of plastic waste: Presence of phthalates in plastics from households and industry

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Eriksen, Marie Kampmann; Martín-Fernández, J. A.

    2016-01-01

    Plastics recycling has the potential to substitute virgin plastics partially as a source of raw materials in plastic product manufacturing. Plastic as a material may contain a variety of chemicals, some potentially hazardous. Phthalates, for instance, are a group of chemicals produced in large...... recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP...

  5. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  6. Multiphase-field model of small strain elasto-plasticity according to the mechanical jump conditions

    Science.gov (United States)

    Herrmann, Christoph; Schoof, Ephraim; Schneider, Daniel; Schwab, Felix; Reiter, Andreas; Selzer, Michael; Nestler, Britta

    2018-04-01

    We introduce a small strain elasto-plastic multiphase-field model according to the mechanical jump conditions. A rate-independent J_2 -plasticity model with linear isotropic hardening and without kinematic hardening is applied exemplary. Generally, any physically nonlinear mechanical model is compatible with the subsequently presented procedure. In contrast to models with interpolated material parameters, the proposed model is able to apply different nonlinear mechanical constitutive equations for each phase separately. The Hadamard compatibility condition and the static force balance are employed as homogenization approaches to calculate the phase-inherent stresses and strains. Several verification cases are discussed. The applicability of the proposed model is demonstrated by simulations of the martensitic transformation and quantitative parameters.

  7. Elastic-plastic behaviour of thick-walled containers considering plastic compressibility

    International Nuclear Information System (INIS)

    Betten, J.; Frosch, H.G.

    1983-01-01

    In this paper the elastic-plastic behaviour of thick-walled pressure vessels with internal and external pressure is studied. To describe the mechanical behaviour of isotropic, plastic compressible materials we use a plastic potential which is a single-valued function of the principle stresses. For cylinders and spheres an analytic expression for the computation of stresses and residual stresses is specified. Afterwards the strains are calculated by using the finite difference method. Some examples will high-light the influence of the plastic compressibility on the behaviour of pressure vessels. (orig.) [de

  8. The accompanying adult: authority to give consent in the UK.

    Science.gov (United States)

    Lal, Seema Madhur Lata; Parekh, Susan; Mason, Carol; Roberts, Graham

    2007-05-01

    Children may be accompanied by various people when attending for dental treatment. Before treatment is started, there is a legal requirement that the operator obtain informed consent for the proposed procedure. In the case of minors, the person authorized to give consent (parental responsibility) is usually a parent. To ascertain if accompanying persons of children attending the Department of Paediatric Dentistry at the Eastman Dental Hospital, London were empowered to give consent for the child's dental treatment. A total of 250 accompanying persons of children attending were selected, over a 6-month period. A questionnaire was used to establish whether the accompanying person(s) were authorized to give consent. The study showed that 12% of accompanying persons had no legal authority to give consent for the child's dental treatment. Clinicians need to be aware of the status of persons accompanying children to ensure valid consent is obtained.

  9. Late-onset Pompe disease: first clinical description in Russia

    Directory of Open Access Journals (Sweden)

    S. S. Nikitin

    2014-01-01

    Full Text Available Late-onset Pompe-disease (LOPD is an adult form of the glycogenosis type II. The age of onset ranges from 1 till 75 y.o. and older. The diagnosis of LOPD is based on the presence of trunk and limb-girdle muscle weakness with hyperlordosis, respiratory failure, ocasionally accompanied by cardiomyopathy, persistent mild elevation of creatine kinase, dry blood spot test of the enzyme activity and DNA-analysis of GAA-gene. Early recognition of the LOPD and beginning of the enzyme replacement therapy is important in preventing severe motor and respiratory deficit, the patient disability and in increasing the survival in those patients.

  10. Plastic flexible films waste management - A state of art review.

    Science.gov (United States)

    Horodytska, O; Valdés, F J; Fullana, A

    2018-04-21

    Plastic flexible films are increasingly used in many applications due to their lightness and versatility. In 2014, the amount of plastic films represented 34% of total plastic packaging produced in UK. The flexible film waste generation rises according to the increase in number of applications. Currently, in developed countries, about 50% of plastics in domestic waste are films. Moreover, about 615,000 tonnes of agricultural flexible waste are generated in the EU every year. A review of plastic films recycling has been conducted in order to detect the shortcomings and establish guidelines for future research. This paper reviews plastic films waste management technologies from two different sources: post-industrial and post-consumer. Clean and homogeneous post-industrial waste is recycled through closed-loop or open-loop mechanical processes. The main differences between these methods are the quality and the application of the recycled materials. Further research should be focused on closing the loops to obtain the highest environmental benefits of recycling. This could be accomplished through minimizing the material degradation during mechanical processes. Regarding post-consumer waste, flexible films from agricultural and packaging sectors have been assessed. The agricultural films and commercial and industrial flexible packaging are recycled through open-loop mechanical recycling due to existing selective waste collection routes. Nevertheless, the contamination from the use phase adversely affects the quality of recycled plastics. Therefore, upgrading of current washing lines is required. On the other hand, household flexible packaging shows the lowest recycling rates mainly because of inefficient sorting technologies. Delamination and compatibilization methods should be further developed to ensure the recycling of multilayer films. Finally, Life Cycle Assessment (LCA) studies on waste management have been reviewed. A lack of thorough LCA on plastic films waste

  11. Mechanically equivalent elastic-plastic deformations and the problem of plastic spin

    Directory of Open Access Journals (Sweden)

    Steigmann David J.

    2011-01-01

    Full Text Available The problem of plastic spin is phrased in terms of a notion of mechanical equivalence among local intermediate configurations of an elastic/ plastic crystalline solid. This idea is used to show that, without further qualification, the plastic spin may be suppressed at the constitutive level. However, the spin is closely tied to an underlying undistorted crystal lattice which, once specified, eliminates the freedom afforded by mechanical equivalence. As a practical matter a constitutive specification of plastic spin is therefore required. Suppression of plastic spin thus emerges as merely one such specification among many. Restrictions on these are derived in the case of rate-independent response.

  12. Path Dependency of High Pressure Phase Transformations

    Science.gov (United States)

    Cerreta, Ellen

    2017-06-01

    At high pressures titanium and zirconium are known to undergo a phase transformation from the hexagonal close packed (HCP), alpha-phase to the simple-hexagonal, omega-phase. Under conditions of shock loading, the high-pressure omega-phase can be retained upon release. It has been shown that temperature, peak shock stress, and texture can influence the transformation. Moreover, under these same loading conditions, plastic processes of slip and twinning are also affected by similar differences in the loading path. To understand this path dependency, in-situ velocimetry measurements along with post-mortem metallographic and neutron diffraction characterization of soft recovered specimens have been utilized to qualitatively understand the kinetics of transformation, quantify volume fraction of retained omega-phase and characterize the shocked alpha and omega-phases. Together the work described here can be utilized to map the non-equilibrium phase diagram for these metals and lend insight into the partitioning of plastic processes between phases during high pressure transformation. In collaboration with: Frank Addesssio, Curt Bronkhorst, Donald Brown, David Jones, Turab Lookman, Benjamin Morrow, Carl Trujillo, Los Alamos National Lab.; Juan Pablo Escobedo-Diaz, University of New South Wales; Paulo Rigg, Washington State University.

  13. Micro-thermomechanical constitutive model of transformation induced plasticity and its application on armour steel

    Energy Technology Data Exchange (ETDEWEB)

    Sun, C.Y. [School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: suncy@me.ustb.edu.cn; Fang, G.; Lei, L.P.; Zeng, P. [Key Laboratory of Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2009-01-15

    Based on the crystallographic theory of martensitic transformation and internal variable constitutive theory, a micromechanical constitutive model of martensitic transformation induced plasticity was developed. Plastic strains of product and parent phases as well as the volume fraction of each martensitic variant were considered as internal variables describing the microstructure evolution. The plasticity flow both in austenite and martensitic variants domain is described by J{sub 2} flow theory. The thermodynamic driving force acting on these internal variables was obtained through the determination of the intrinsic dissipation due to plastic flow and the growth of martensitic domains. The evolution laws of the internal variables are derived, furthermore macroscopic response due to the change of internal variables is obtained. Thermomechanical behavior of armour steel under uniaxial loading was tested which showed a good agreement with experimental results.

  14. Micro-thermomechanical constitutive model of transformation induced plasticity and its application on armour steel

    International Nuclear Information System (INIS)

    Sun, C.Y.; Fang, G.; Lei, L.P.; Zeng, P.

    2009-01-01

    Based on the crystallographic theory of martensitic transformation and internal variable constitutive theory, a micromechanical constitutive model of martensitic transformation induced plasticity was developed. Plastic strains of product and parent phases as well as the volume fraction of each martensitic variant were considered as internal variables describing the microstructure evolution. The plasticity flow both in austenite and martensitic variants domain is described by J 2 flow theory. The thermodynamic driving force acting on these internal variables was obtained through the determination of the intrinsic dissipation due to plastic flow and the growth of martensitic domains. The evolution laws of the internal variables are derived, furthermore macroscopic response due to the change of internal variables is obtained. Thermomechanical behavior of armour steel under uniaxial loading was tested which showed a good agreement with experimental results

  15. Study of the scheme of two-beam accelerator driver with accompanying electromagnetic wave

    International Nuclear Information System (INIS)

    Elzhov, A.V.; Kaminskij, A.K.; Kazacha, V.I.; Perel'shtejn, E.A.; Sedykh, S.N.; Sergeev, A.P.

    2000-01-01

    A novel scheme of two-beam accelerator (TBA) driver based on a linear induction accelerator is considered. In this scheme the bunched beam propagates in the accompanying enhanced microwave that provides the steady longitudinal beam bunching along the whole driver. A travelling wave tube (TWT) is used as the wave-slowing periodic structure. Major merits of the driver scheme in hand are the possibilities of providing the microwave phase and amplitude stability and the preliminary beam bunching at a rather low initial energy (∼ 1 MeV). The numerical simulation has shown that a steady state could be found when electron bunches accompanied by an amplified microwave are simultaneously accelerated in the external electric field. The total power, which is inserted into the beam by the accelerating field, transforms into the microwave power in the steady state. The first set of experiments was fulfilled with the buncher on the base of the JINR LIU-3000 linac (electron beam energy ∼ 600 keV, electron current ∼ 150 A). The considerable level of the amplified microwave power (∼ 5 MW) and high enough bunching parameter (∼ 0.4) were obtained. The electron beam bunching at the frequency of 36.4 GHz was registered by means of the Cherenkov radiation of the electron bunches that occurred at their passing through the special target. The beam keeps a high bunching level at the distance ∼ 10 cm from the TWT exit being accompanied by the amplified microwave

  16. Plastics and health risks.

    Science.gov (United States)

    Halden, Rolf U

    2010-01-01

    By 2010, the worldwide annual production of plastics will surpass 300 million tons. Plastics are indispensable materials in modern society, and many products manufactured from plastics are a boon to public health (e.g., disposable syringes, intravenous bags). However, plastics also pose health risks. Of principal concern are endocrine-disrupting properties, as triggered for example by bisphenol A and di-(2-ethylhexyl) phthalate (DEHP). Opinions on the safety of plastics vary widely, and despite more than five decades of research, scientific consensus on product safety is still elusive. This literature review summarizes information from more than 120 peer-reviewed publications on health effects of plastics and plasticizers in lab animals and humans. It examines problematic exposures of susceptible populations and also briefly summarizes adverse environmental impacts from plastic pollution. Ongoing efforts to steer human society toward resource conservation and sustainable consumption are discussed, including the concept of the 5 Rs--i.e., reduce, reuse, recycle, rethink, restrain--for minimizing pre- and postnatal exposures to potentially harmful components of plastics.

  17. An increased flip angle in late phase Gd-EOB-DTPA MRI shows improved performance in bile duct visualization compared to T2w-MRCP

    Energy Technology Data Exchange (ETDEWEB)

    Stelter, Lars, E-mail: lars.stelter@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Freyhardt, Patrick, E-mail: patrick.freyhardt@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Grieser, Christian, E-mail: christian.grieser@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Walter, Thula, E-mail: thula.walter@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Geisel, Dominik, E-mail: dominik.geisel@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Baur, Alexander, E-mail: alexander.baur@charite.de [Klinik für Radiologie, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); and others

    2014-10-15

    Highlights: • EOB-MRC acquired with a flip angle of 35° revealed a better diagnostic performance compared to T2w-MRCP. • EOB-MRC increased the readers’ confidence in identifying anatomic variations of the biliary tree. • As EOB-MRC comprises functional information it is a valuable adjunct to T2w-MRCP. - Abstract: Objectives: To estimate the additional value of an increased flip angle of 35° in late phase Gd-EOB-DTPA-enhanced magnetic resonance cholangiography, as compared to T2w-MRCP. Methods: 40 adult patients underwent Gd-EOB-DTPA enhanced MRI of the liver including a T2-weighted 3D TSE MRCP (T2w-MRCP) as well as a late phase T1-weighted THRIVE sequences applying a flip angle of 35° (fa35). Two experienced observers evaluated the images regarding the delineation of the different biliary regions using a three-point grading system. A five-point scale was applied to determine the readers’ confidence in identifying anatomical variations of the biliary tree. ROI analysis was performed to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Results: The quality for visualizing the biliary tree differed between T2w-MRCP and fa35 (p = <0.001). Late phase EOB-MRC was rated as good for delineating the entire biliary system, whereas T2w-MRCP received an overall poor rating. Especially the depiction of the intrahepatic bile ducts was estimated as problematic in T2w-MRCP. T2w-MRCP and fa35 revealed a discordant assessment of anatomical variations in 12.5% of the cases, comprising a generally higher confidence level for fa35 (4.0 ± 1.1 vs. 2.2 ± 1.2, p = <0.001). SNR proofed to be significantly higher in fa35 (p = <0.001), whereas T2w-MRCP revealed a significantly higher CNR (<0.001). Conclusions: Gd-EOB-DTPA enhanced magnetic resonance cholangiography acquired with a flip angle of 35° revealed a better diagnostic performance compared to T2w-MRCP and might be a valuable adjunct in assessing functional bile duct abnormalities.

  18. Recycling of plastic waste: Presence of phthalates in plastics from households and industry

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Eriksen, Marie Kampmann; Martín-Fernández, J. A.

    2016-01-01

    recognised, the influence of plastic recycling on phthalate content has been hypothesised but not well documented. In the present work we analysed selected phthalates (DMP, DEP, DPP, DiBP, DBP, BBzP, DEHP, DCHP and DnOP) in samples of waste plastics as well as recycled and virgin plastics. DBP, DiBP and DEHP...... product manufacturing (labelling, gluing, etc.) and were not removed following recycling of household waste plastics. Furthermore, DEHP was identified as a potential indicator for phthalate contamination of plastics. Close monitoring of plastics intended for phthalates-sensitive applications...

  19. Oscillation-Driven Spike-Timing Dependent Plasticity Allows Multiple Overlapping Pattern Recognition in Inhibitory Interneuron Networks

    DEFF Research Database (Denmark)

    Garrido, Jesús A.; Luque, Niceto R.; Tolu, Silvia

    2016-01-01

    The majority of operations carried out by the brain require learning complex signal patterns for future recognition, retrieval and reuse. Although learning is thought to depend on multiple forms of long-term synaptic plasticity, the way this latter contributes to pattern recognition is still poorly...... and at the inhibitory interneuron-interneuron synapses, the interneurons rapidly learned complex input patterns. Interestingly, induction of plasticity required that the network be entrained into theta-frequency band oscillations, setting the internal phase-reference required to drive STDP. Inhibitory plasticity...... effectively distributed multiple patterns among available interneurons, thus allowing the simultaneous detection of multiple overlapping patterns. The addition of plasticity in intrinsic excitability made the system more robust allowing self-adjustment and rescaling in response to a broad range of input...

  20. Experimental study of stress-induced localized transformation plastic zones in tetragonal zirconia polycrystalline ceramics

    International Nuclear Information System (INIS)

    Sun, Q.; Zhao, Z.; Chen, W.; Qing, X.; Xu, X.; Dai, F.

    1994-01-01

    Stress-induced martensitic transformation plastic zones in ceria-stabilized tetragonal zirconia polycrystalline ceramics (Ce-TZP), under loading conditions of uniaxial tension, compression, and three-point bending, are studied by experiments. The transformed monoclinic phase volume fraction distribution and the corresponding plastic strain distribution and the surface morphology (surface uplift) are measured by means of moire interferometry, Raman microprobe spectroscopy, and the surface measurement system. The experimental results from the above three kinds of specimens and methods consistently show that the stress-induced transformation at room temperature of the above specimen is not uniform within the transformation zone and that the plastic deformation is concentrated in some narrow band; i.e., macroscopic plastic flow localization proceeds during the initial stage of plastic deformation. Flow localization phenomena are all observed in uniaxial tension, compression, and three-point bending specimens. Some implications of the flow localization to the constitutive modeling and toughening of transforming thermoelastic polycrystalline ceramics are explored

  1. Effect of a prostaglandin - given rectally for prevention of radiation-induced acute proctitis - on late rectal toxicity. Results of phase III randomized, placebo-controlled, double-blind study

    International Nuclear Information System (INIS)

    Kertesz, Tereza; Herrmann, Markus K.A.; Christiansen, Hans; Hermann, Robert M.; Hess, Clemens F.; Hille, Andrea; Zapf, Antonia; Pradier, Olivier; Schmidberger, Heinz

    2009-01-01

    Background and purpose: to assess the late effect of a prostaglandin, given rectally during irradiation, on late rectal toxicity. In the acute treatment setting no significant differences in reducing the incidence of acute proctitis symptoms in patients receiving misoprostol, however, significantly more rectal bleeding had been reported. Patients and methods: a total of 100 patients who had undergone radiotherapy for prostate cancer had been entered into this phase III randomized, placebo-controlled, double-blind study with misoprostol or placebo suppositories. The toxicity was evaluated yearly after cessation of irradiation by the RTOG/LENT-SOMA scale. Results: the median follow-up was 50 months. 20 patients suffered from grade 1, four patients from grade 2 as well, and three patients only from grade 2 toxicity. Frequency, bleeding and urgency were the most commonly reported symptoms. In keeping with other studies and clinical experience, the symptoms peaked within the first 2 years with a median for grade 1 of 13 months and for grade 2 of 15 months. The presence of acute toxicity grade 2 showed a correlation with the development of any late toxicity (p = 0.03). Any acute rectal bleeding was significant correlated with any late rectal bleeding (p = 0.017). Conclusion: misoprostol given as once-daily suppository for prevention of acute radiation-induced proctitis does neither influence the incidence and severity of radiation-induced acute nor late rectal toxicity. Misoprostol has no negative impact on the incidence and severity of late rectal bleeding, in contrast to acute rectal bleeding. The routine clinical use of misoprostol suppositories cannot be recommended. (orig.)

  2. Effect of a prostaglandin - given rectally for prevention of radiation-induced acute proctitis - on late rectal toxicity. Results of phase III randomized, placebo-controlled, double-blind study

    Energy Technology Data Exchange (ETDEWEB)

    Kertesz, Tereza; Herrmann, Markus K.A.; Christiansen, Hans; Hermann, Robert M.; Hess, Clemens F.; Hille, Andrea [Dept. of Radiotherapy and Radiooncology, Univ. of Goettingen (Germany); Zapf, Antonia [Dept. of Medical Statistics, Univ. of Goettingen (Germany); Pradier, Olivier [Dept. of Radiotherapy and Radiooncology, Univ. of Brest (France); Schmidberger, Heinz [Dept. of Radiotherapy and Radiooncology, Univ. of Mainz (Germany)

    2009-09-15

    Background and purpose: to assess the late effect of a prostaglandin, given rectally during irradiation, on late rectal toxicity. In the acute treatment setting no significant differences in reducing the incidence of acute proctitis symptoms in patients receiving misoprostol, however, significantly more rectal bleeding had been reported. Patients and methods: a total of 100 patients who had undergone radiotherapy for prostate cancer had been entered into this phase III randomized, placebo-controlled, double-blind study with misoprostol or placebo suppositories. The toxicity was evaluated yearly after cessation of irradiation by the RTOG/LENT-SOMA scale. Results: the median follow-up was 50 months. 20 patients suffered from grade 1, four patients from grade 2 as well, and three patients only from grade 2 toxicity. Frequency, bleeding and urgency were the most commonly reported symptoms. In keeping with other studies and clinical experience, the symptoms peaked within the first 2 years with a median for grade 1 of 13 months and for grade 2 of 15 months. The presence of acute toxicity grade 2 showed a correlation with the development of any late toxicity (p = 0.03). Any acute rectal bleeding was significant correlated with any late rectal bleeding (p = 0.017). Conclusion: misoprostol given as once-daily suppository for prevention of acute radiation-induced proctitis does neither influence the incidence and severity of radiation-induced acute nor late rectal toxicity. Misoprostol has no negative impact on the incidence and severity of late rectal bleeding, in contrast to acute rectal bleeding. The routine clinical use of misoprostol suppositories cannot be recommended. (orig.)

  3. The effect of nanocrystallization and free volume on the room temperature plasticity of Zr-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Mondal, K.; Ohkubo, T.; Toyama, T.; Nagai, Y.; Hasegawa, M.; Hono, K.

    2008-01-01

    To understand the mechanism of the room temperature plasticity of bulk metallic glasses (BMGs), microstructure observations, density measurements and positron annihilation studies were carried out for Zr-based BMGs cast at various temperatures and post-annealed under different conditions. We found that higher casting temperatures cause partial crystallization, which enhance the plasticity as long as the volume fraction of the crystalline phase is low. However, a similar nanocrystalline microstructure produced by post-annealing often leads to a large loss of plasticity, while certain conditions enhance the plasticity. Based on density measurements and positron annihilation lifetime spectroscopy, we conclude that the relative contribution of free volume and nanocrystallization is important for acquiring plasticity in metallic glasses

  4. Ex-situ bioremediation of Brazilian soil contaminated with plasticizers process wastes

    Directory of Open Access Journals (Sweden)

    I. D. Ferreira

    2012-03-01

    Full Text Available The aim of this research was to evaluate the bioremediation of a soil contaminated with wastes from a plasticizers industry, located in São Paulo, Brazil. A 100-kg soil sample containing alcohols, adipates and phthalates was treated in an aerobic slurry-phase reactor using indigenous and acclimated microorganisms from the sludge of a wastewater treatment plant of the plasticizers industry (11gVSS kg-1 dry soil, during 120 days. The soil pH and temperature were not corrected during bioremediation; soil humidity was corrected weekly to maintain 40%. The biodegradation of the pollutants followed first-order kinetics; the removal efficiencies were above 61% and, among the analyzed plasticizers, adipate was removed to below the detection limit. Biological molecular analysis during bioremediation revealed a significant change in the dominant populations initially present in the reactor.

  5. Plastic deformation and hysteresis for hydrogen storage in Pd–Rh alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cappillino, P.J., E-mail: pcappil@sandia.gov [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States); Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); Ong, M.D. [Department of Physics, Whitworth University, Spokane, WA 99251 (United States); Wolfer, W.G.; Yang, N.Y. [Sandia National Laboratories, PO Box 969, Mail Stop 9292, Livermore, CA 94551 (United States)

    2014-02-15

    Highlights: • Experimental evidence of plastic work resulting from hydriding of palladium is presented. • A model of this plastic work was generated and correlated to hysteresis losses. • This hysteresis is thought to be important to the lifetime of hydrogen storage materials. • Yield strength values predicted by this model agree with measured hardness. -- Abstract: The hysteresis observed when reversibly absorbing and desorbing hydrogen in metals is currently not fully understood. In general, a hysteresis represents energy that is dissipated during a cycle, but the underlying mechanism of dissipation is still uncertain. It has been suggested that the hysteresis arises either from plastic work, or from elastic strains associated with the accommodation of the hydride phase, or from both. We present here experimental evidence that implicates plastic deformation as the cause of the hysteresis in a Pd–Rh alloy. The plastic work is evident from the increased dislocation density, from the accumulation of surface steps from slip bands, from line broadening of X-ray diffraction peaks, and from an increase in hardness with the number of hydriding cycles. A model of this plastic work is developed that depends on an effective yield strength. When this model is correlated with the measured hysteresis losses, two values are found for the effective yield strength. The lower value is shown to agree with yield strength values derived from Vickers hardness measurements. The hysteresis areas for repeated cycles of absorption and desorption decrease little with the number of cycles which is reminiscent of the plastic deformation hysteresis during low-cycle fatigue of metals. This similarity further confirms the plastic nature of the hydriding hysteresis.

  6. A study of time over threshold (TOT) technique for plastic scintillator counter

    International Nuclear Information System (INIS)

    Wu Jinjie; Chinese Academy of Sciences, Beijing; Heng Yuekun; Sun Zhijia; Wu Chong; Yang Guian; Jiang Chun Hua; Zhao Yuda

    2008-01-01

    A new charge measurement method, time over threshold (TOT), has been used in some gas detectors lately. Here TOT is studied for TOF system, made of plastic scintillator counter, which can simplify the electronics of the system. The signal characteristics are measured and analyzed with a high quality oscilloscope, including noise, pedestal, signal amplitude, total charge, rise time and the correlation between them. The TOT and charge are related and can be fitted by some empirical formula. The charge measurement resolution by TOT is given and this will help the design of TOF electronics. (authors)

  7. Essential results of analyses accompanying the leak rate experiments E22 at HDR

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1994-01-01

    Under the E22 test group of phase III of the HDR safety programme, experiments were performed on the crack opening and leak rate behaviour of pipe components of smaller nominal bores. The experiments were complemented by computations, in particular verifications, to qualify the computation models as one of the main aims of the HDR safety programme. Most of the analyses to determine crack openings were performed by means of the finite-element method, including elastic-plastic materials behaviour and, complementarily, assessing engineering methods. The leak rate was calculated by means of separate 2-phase computation models. Altogether, it may be concluded from the structural and fracture mechanical experiments with pipes, elbows and branch pieces, that crack openings and incipient cracks at loading with internal pressure or bending moment can be described with good accuracy by means of the finite-element programme ADINA and the developed FE-models. (orig.) [de

  8. Challenges in plastics recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study...... was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamination, presence of additives, non-polymer impurities, and polymer degradation. Deprivation of plastics quality......, with respect to recycling, has been shown to happen throughout the plastics value chain, but steps where improvements may happen have been preliminary identified. Example of Cr in plastic samples analysed showed potential spreading and accumulation of chemicals ending up in the waste plastics. In order...

  9. Structural and metamorphic evolution of the Orocopia Schist and related rocks, southern California: Evidence for late movement on the Orocopia fault

    Science.gov (United States)

    Jacobson, Carl E.; Dawson, M. Robert

    1995-08-01

    The Pelona, Orocopia, and Rand Schists (POR schists) of southern California and southwesternmost Arizona are late Mesozoic or early Tertiary subduction complexes that underlie Precambrian to Mesozoic continental basement along the low-angle Vincent-Chocolate Mountains (VCM) fault system. The VCM faults are often considered to be remnants of the original subduction zone, but recent work indicates that many have undergone substantial postsubduction reactivation. In the Orocopia Mountains, for example, the Orocopia Schist exhibits an exceptionally complex structural and metamorphic history due to multiple periods of movement along the Orocopia fault. Structures in the schist include isoclinal folds with axial-planar schistosity, open-to-tight folds that fold schistosity, penetrative stretching lineations, and crenulation lineations, all of which show a nearly 360° range in trend. Folds and lineations that trend approximately NE-SW occur throughout the schist and are thought to be part of an early phase of deformation related to subduction. Folds of this orientation show no consistent vergence. Folds and lineations that trend approximately NW-SE are concentrated near the Orocopia fault and are interpreted to have formed during exhumation of the schist. The NW-SE trending folds, and shear indicators in late-stage mylonite at the top of the schist, consistently verge NE. The exhumation event culminated in emplacement of the schist against brittlely deformed upper plate. Exhumation of the Orocopia Schist was accompanied by retrograde replacement of garnet, biotite, epidote, and calcic amphibole by chlorite, calcite, and sericite. Matrix amphibole has a lower Na/Al ratio than amphibole inclusions in albite, consistent with a late-stage decrease in pressure. As NE vergence in the Orocopia Mountains is associated with exhumation of the schist, the NE movement along other segments of the VCM fault may also be late and therefore have no bearing on the facing direction of the

  10. Experience-dependent plasticity from eye opening enables lasting, visual cortex-dependent enhancement of motion vision.

    Science.gov (United States)

    Prusky, Glen T; Silver, Byron D; Tschetter, Wayne W; Alam, Nazia M; Douglas, Robert M

    2008-09-24

    Developmentally regulated plasticity of vision has generally been associated with "sensitive" or "critical" periods in juvenile life, wherein visual deprivation leads to loss of visual function. Here we report an enabling form of visual plasticity that commences in infant rats from eye opening, in which daily threshold testing of optokinetic tracking, amid otherwise normal visual experience, stimulates enduring, visual cortex-dependent enhancement (>60%) of the spatial frequency threshold for tracking. The perceptual ability to use spatial frequency in discriminating between moving visual stimuli is also improved by the testing experience. The capacity for inducing enhancement is transitory and effectively limited to infancy; however, enhanced responses are not consolidated and maintained unless in-kind testing experience continues uninterrupted into juvenile life. The data show that selective visual experience from infancy can alone enable visual function. They also indicate that plasticity associated with visual deprivation may not be the only cause of developmental visual dysfunction, because we found that experientially inducing enhancement in late infancy, without subsequent reinforcement of the experience in early juvenile life, can lead to enduring loss of function.

  11. Individual differences in behavioural plasticities.

    Science.gov (United States)

    Stamps, Judy A

    2016-05-01

    Interest in individual differences in animal behavioural plasticities has surged in recent years, but research in this area has been hampered by semantic confusion as different investigators use the same terms (e.g. plasticity, flexibility, responsiveness) to refer to different phenomena. The first goal of this review is to suggest a framework for categorizing the many different types of behavioural plasticities, describe examples of each, and indicate why using reversibility as a criterion for categorizing behavioural plasticities is problematic. This framework is then used to address a number of timely questions about individual differences in behavioural plasticities. One set of questions concerns the experimental designs that can be used to study individual differences in various types of behavioural plasticities. Although within-individual designs are the default option for empirical studies of many types of behavioural plasticities, in some situations (e.g. when experience at an early age affects the behaviour expressed at subsequent ages), 'replicate individual' designs can provide useful insights into individual differences in behavioural plasticities. To date, researchers using within-individual and replicate individual designs have documented individual differences in all of the major categories of behavioural plasticities described herein. Another important question is whether and how different types of behavioural plasticities are related to one another. Currently there is empirical evidence that many behavioural plasticities [e.g. contextual plasticity, learning rates, IIV (intra-individual variability), endogenous plasticities, ontogenetic plasticities) can themselves vary as a function of experiences earlier in life, that is, many types of behavioural plasticity are themselves developmentally plastic. These findings support the assumption that differences among individuals in prior experiences may contribute to individual differences in behavioural

  12. Durability of wood plastic composites manufactured from recycled plastic

    Directory of Open Access Journals (Sweden)

    Irina Turku

    2018-03-01

    Full Text Available The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2–30%, depending on the plastic source. Wettability of the samples was shown to play a significant role in their stability. Chemical analysis with infrared spectroscopy and surface observation with a scan electron microscope confirmed the mechanical test results. Incorporation of carbon black retained the properties during weathering, reducing the wettability of the sample, diminishing the change of mechanical properties, and improving color stability. Keywords: Environmental science, Mechanical engineering, Materials science

  13. Phenotypic plasticity, costs of phenotypes, and costs of plasticity

    DEFF Research Database (Denmark)

    Callahan, Hilary S; Maughan, Heather; Steiner, Uli

    2008-01-01

    Why are some traits constitutive and others inducible? The term costs often appears in work addressing this issue but may be ambiguously defined. This review distinguishes two conceptually distinct types of costs: phenotypic costs and plasticity costs. Phenotypic costs are assessed from patterns...... of covariation, typically between a focal trait and a separate trait relevant to fitness. Plasticity costs, separable from phenotypic costs, are gauged by comparing the fitness of genotypes with equivalent phenotypes within two environments but differing in plasticity and fitness. Subtleties associated with both...... types of costs are illustrated by a body of work addressing predator-induced plasticity. Such subtleties, and potential interplay between the two types of costs, have also been addressed, often in studies involving genetic model organisms. In some instances, investigators have pinpointed the mechanistic...

  14. Plastic waste as a resource. Strategies for reduction and utilization of plastic waste

    OpenAIRE

    Pasqual i Camprubí, Gemma

    2010-01-01

    Plastic materials have experienced a spectacular rate of growth in recent decades, consequently, production of plastics, and likewise their consumption, has increased markedly since 1950. Moreover, they are lightweight and durable, as well as can be moulded into a variety of products that can be manufactured in many different types of plastic and in a wide range of applications. Inevitably, continually increasing amounts of used plastic are originating daily, resulting in a plastic waste prob...

  15. Co@MWNTs-Plastic: A novel electrode for NaBH4 oxidation

    International Nuclear Information System (INIS)

    Zhang, Dongming; Ye, Ke; Cao, Dianxue; Wang, Bin; Cheng, Kui; Li, Yiju; Wang, Guiling; Xu, Yang

    2015-01-01

    Highlights: • MP substrate was fabricated by adhering MWNTs on a piece of obsoleted plastic bag. • Co nano-thorns were prepared by a simple electrodeposition method on the MP surface. • MP owns a superior stability in strong alkaline environment. • CMP exhibits a high catalytic activity for NaBH 4 electrooxidation. • The possible mechanisms of NaBH 4 electrooxidation on CMP was discussed. - Abstract: A novel multi-walled carbon nanotubes (MWNTs)-Plastic (MP) substrate was first fabricated by adhering MWNTs on a piece of obsoleted plastic bag, and Co nano-thorns were subsequently prepared by a simple electrodeposition method on the MP surface. The morphology and phase structure of the as-prepared Co@MWNTs-Plastic (CMP) catalytic electrode are characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffractometer. The catalytic activity of the CMP electrode for NaBH 4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The employing of waste plastic bags reduces white pollution and the MP substrate exhibits superior stability in alkaline solution. The 3D CMP catalytic electrode owns a high electrochemical activity for NaBH 4 oxidation. Moreover, we discussed the possible mechanisms of NaBH 4 electrooxidation on the CMP

  16. Particle stabilization of plastic flow in nanostructured Al-1 %Si Alloy

    DEFF Research Database (Denmark)

    Huang, Tianlin; Li, Chao; Wu, Guilin

    2014-01-01

    A nanostructured Al-1 %Si alloy containing a dispersion of Si particles in ultrapure aluminum (99.9996 %) was produced by heavy cold rolling to study the effect of second-phase particles on the occurrence of plastic instability during tensile testing of a nanostructured metal. Tensile tests were...

  17. Thermal degradation and plasticizing mechanism of poly(vinyl chloride) plasticized with a novel cardanol derived plasticizer

    Science.gov (United States)

    Chen, J.; Nie, X. A.; Jiang, J. C.; Zhou, Y. H.

    2018-01-01

    A natural plasticizer cardanol derivatives glycidyl ether (CGE) was synthesized and employed as a plasticizer for the poly(vinyl chloride). The effect of CGE on thermal degradation of PVC films and its plasticizing mechanism were firstly reported. The molecular structure of CGE was characterized with Fourier transform infrared spectroscopy (FTIR). Thermal properties, degradation properties and compatibility of the PVC films were investigated by Differential scanning calorimeter analysis (DSC), Thermogravimetric analysis (TGA) and FTIR, respectively. Compared with the commercial plasticizers dioctylphthalate (DOP), CGE can endow PVC film with a decrease of 4.31 °C in glass transition temperature (Tg), an increase of 24.01 °C and 25.53 °C in 10% weight loss (T 10) and 50% weight loss (T 50) respectively, and a higher activetion energy of thermal degradation (Ea ).

  18. Phenotypic plasticity in Drosophila cactophilic species: the effect of competition, density, and breeding sites.

    Science.gov (United States)

    Fanara, Juan Jose; Werenkraut, Victoria

    2017-08-01

    Changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organism to cope with environmental unpredictability. Phenotypic plasticity is a major aspect of adaptation and it has been involved in population dynamics of interacting species. In this study, phenotypic plasticity (i.e., environmental sensitivity) of morphological adaptive traits were analyzed in the cactophilic species Drosophila buzzatii and Drosophila koepferae (Diptera: Drosophilidae) considering the effect of crowding conditions (low and high density), type of competition (intraspecific and interspecific competition) and cacti hosts (Opuntia and Columnar cacti). All traits (wing length, wing width, thorax length, wing loading and wing aspect) showed significant variation for each environmental factor considered in both Drosophila species. The phenotypic plasticity pattern observed for each trait was different within and between these cactophilic Drosophila species depending on the environmental factor analyzed suggesting that body size-related traits respond almost independently to environmental heterogeneity. The effects of ecological factors analyzed in this study are discussed in order to elucidate the causal factors investigated (type of competition, crowding conditions and alternative host) affecting the election of the breeding site and/or the range of distribution of these cactophilic species. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  19. CURED I - LENT. Late effects of cancer treatment on normal tissues

    International Nuclear Information System (INIS)

    Rubin, P.; Okunieff, P.; Constine, L.S.; Rochester Univ. School of Medicine and Dentistry, Rochester, NY; Marks, L.B.

    2008-01-01

    The search for the most favorable therapeutic ratio - at which ablation of cancer is achieved while normal tissues are conserved - has been modern radiation oncology's equivalent of the quest for the Holy Grail. Our awareness of the late effects of radiation grew during the past century as new modalities were introduced. Heightened normal tissue reactions accompanied the higher rates of cancer ablation achieved by escalation of radiation doses, accelerated fractionated radiotherapy, and aggressive concurrent chemotherapy and radiation regimens. This volume is based on the LENT V NCI-sponsored meeting held in May 2004 and the CURED I conference held in 2006. Written by experts in the field, it addresses a number of critical topics relating to late effects, such as mechanisms of injury, the role of screening, options for interventions, second malignancies, and prevention. It is hoped that it will assist the reader in understanding how to prevent and treat the long-term side-effects of irradiation. (orig.)

  20. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  1. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  2. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1977-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  3. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1976-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  4. On the fast amorphous phase growth in plastically deformed metallic couples

    International Nuclear Information System (INIS)

    Mazzone, G.; Montone, A.; Antisari, M.V.

    1993-01-01

    The authors have modeled the kinetics of glass formation at the Ni-Zr interface of plastically deformed diffusion couples on the basis of a free volume description of glass structure, taking also into account the structural effects of an externally applied stress. Owing to the complexity of the problem several approximations have necessarily been introduced, the main ones being probably the simplified description of the structure and of the tensile behavior of a metallic glass and the use of the Spaepen Eqs. in an alloy system. However, these approximations do not seem to significantly affect the main trends displayed by the computations, that is the high value of D, the exponential dependence of x on var-epsilon and the low value of the activation energy, in agreement with experimental trends (3) not easily attributable to other causes. Of course, the numerical values of the free parameters have to be considered an approximate evaluation of the corresponding physical quantities. However, despite of the above limitations, their values are physically plausible. In conclusion the authors have shown that the present model describes in a quantitative way the kinetics of solid state amorphization at the interface of a diffusion couple plastically deformed during the reaction. The effective diffusion coefficient increases by several orders of magnitude as a consequence of a small increase in vf driven by the stress required to deform the growing film. The effects of strain rate and deformation time balance each other almost exactly so that the film thickness increases exponentially with the total deformation of the diffusion couple

  5. Morphological brain plasticity induced by musical expertise is accompanied by modulation of functional connectivity at rest.

    Science.gov (United States)

    Fauvel, Baptiste; Groussard, Mathilde; Chételat, Gaël; Fouquet, Marine; Landeau, Brigitte; Eustache, Francis; Desgranges, Béatrice; Platel, Hervé

    2014-04-15

    The aim of this study was to explore whether musical practice-related gray matter increases in brain regions are accompanied by modifications in their resting-state functional connectivity. 16 young musically experienced adults and 17 matched nonmusicians underwent an anatomical magnetic resonance imaging (MRI) and a resting-state functional MRI (rsfMRI). A whole-brain two-sample t test run on the T1-weighted structural images revealed four clusters exhibiting significant increases in gray matter (GM) volume in the musician group, located within the right posterior and middle cingulate gyrus, left superior temporal gyrus and right inferior orbitofrontal gyrus. Each cluster was used as a seed region to generate and compare whole-brain resting-state functional connectivity maps. The two clusters within the cingulate gyrus exhibited greater connectivity for musicians with the right prefrontal cortex and left temporal pole, which play a role in autobiographical and semantic memory, respectively. The cluster in the left superior temporal gyrus displayed enhanced connectivity with several language-related areas (e.g., left premotor cortex, bilateral supramarginal gyri). Finally, the cluster in the right inferior frontal gyrus displayed more synchronous activity at rest with claustrum, areas thought to play a role in binding sensory and motor information. We interpreted these findings as the consequence of repeated collaborative use in general networks supporting some of the memory, perceptual-motor and emotional features of musical practice. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Mechanisms of Plastic Deformation in Collagen Networks Induced by Cellular Forces.

    Science.gov (United States)

    Ban, Ehsan; Franklin, J Matthew; Nam, Sungmin; Smith, Lucas R; Wang, Hailong; Wells, Rebecca G; Chaudhuri, Ovijit; Liphardt, Jan T; Shenoy, Vivek B

    2018-01-23

    Contractile cells can reorganize fibrous extracellular matrices and form dense tracts of fibers between neighboring cells. These tracts guide the development of tubular tissue structures and provide paths for the invasion of cancer cells. Here, we studied the mechanisms of the mechanical plasticity of collagen tracts formed by contractile premalignant acinar cells and fibroblasts. Using fluorescence microscopy and second harmonic generation, we quantified the collagen densification, fiber alignment, and strains that remain within the tracts after cellular forces are abolished. We explained these observations using a theoretical fiber network model that accounts for the stretch-dependent formation of weak cross-links between nearby fibers. We tested the predictions of our model using shear rheology experiments. Both our model and rheological experiments demonstrated that increasing collagen concentration leads to substantial increases in plasticity. We also considered the effect of permanent elongation of fibers on network plasticity and derived a phase diagram that classifies the dominant mechanisms of plasticity based on the rate and magnitude of deformation and the mechanical properties of individual fibers. Plasticity is caused by the formation of new cross-links if moderate strains are applied at small rates or due to permanent fiber elongation if large strains are applied over short periods. Finally, we developed a coarse-grained model for plastic deformation of collagen networks that can be employed to simulate multicellular interactions in processes such as morphogenesis, cancer invasion, and fibrosis. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  7. Time between plastic displacements of elasto-plastic oscillators subject to Gaussian white noise

    DEFF Research Database (Denmark)

    Tarp-Johansen, Niels Jacob; Ditlevsen, Ove Dalager

    2001-01-01

    A one degree of freedom elasto-plastic oscillator subject to stationary Gaussian white noise has a plastic displacement response process of intermittent character. During shorter or longer time intervals the oscillator vibrates within the elastic domain without undergoing any plastic displacements...... between the clumps of plastic displacements. This is needed for a complete description of the plastic displacement process. A quite accurate fast simulation procedure is presented based on an amplitude model to determine the short waiting times in the transient regime of the elastic vibrations existing...

  8. Effect of plastic deformation on the supercooled austenite transformations of the Cr-Mo steel with Nb, Ti and B microadditions

    International Nuclear Information System (INIS)

    Adamczyk, J.; Opiela, M.

    1998-01-01

    Effect of plastic deformation at austenizing temperature was investigated on phase transformations, structure and hardness of the supercooled austenite transformation products of the Cr-Mo constructional steel with Nb, Ti and B microadditions. Basing on the analysis of the phase transformation plots of the supercooled undeformed austenite and of the supercooled and plastically deformed one, it was found out that direct cooling of specimens after completing their plastic deformation in the above mentioned conditions, results in significant acceleration of the α→β, and ferritic and pearlitic transformations, and in the decrease of transformation products hardness. These phenomena are of great importance for working out of the thermo-mechanical treatment of products made from the heat-treated microalloyed steel. (author)

  9. Making the End as Good as the Beginning: Financial Planning and Retirement for Women Plastic Surgeons.

    Science.gov (United States)

    Johnson, Debra J; Shenaq, Deana; Thakor, Manisha

    2016-10-01

    Financial planning is critically important to ensure financial security both during a plastic surgical career and in retirement. Unfortunately, plastic surgery training includes very little in the way of financial planning. The information that is available in the literature is mostly geared toward men. Women, with longer lifespans and more family care responsibilities, have unique needs when it comes to financial planning. Adequate attention must also be paid to life after retirement. A plastic surgical career can be all-encompassing, and thus women need to carefully plan volunteer activities, new hobbies, and even a second career to make their retirement years fulfilling and enjoyable. Key points regarding financial planning during the various phases of a woman plastic surgeon's career are discussed. Options for retirement are presented.

  10. Bacterial Growth Phase Influences Methylmercury Production by the Sulfate-Reducing Bacterium Desulfovibrio desulfuricans ND132

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Abir [ORNL; Brooks, Scott C [ORNL; Miller, Carrie L [ORNL; Mosher, Jennifer J [ORNL; Yin, Xiangping Lisa [ORNL; Drake, Meghan M [ORNL

    2011-01-01

    The effect of bacterial growth phase is an aspect of mercury (Hg) methylation that previous studies have not investigated in detail. Here we consider the effect of growth phase (mid-log, late-log and late stationary phase) on Hg methylation by the known methylator Desulfovibrio desulfuricans ND132. We tested the addition of Hg alone (chloride-complex), Hg with Suwannee River natural organic matter (SRNOM) (unequilibrated), and Hg equilibrated with SRNOM on monomethylmercury (MMHg) production by ND132 over a growth curve in pyruvate-fumarate media. This NOM did not affect MMHg production even under very low Hg:SRNOM ratios, where Hg binding is predicted to be dominated by high energy sites. Adding Hg or Hg-NOM to growing cultures 24h before sampling (late addition) resulted in {approx}2x greater net fraction of Hg methylated than for comparably aged cultures exposed to Hg from the initial culture inoculation (early addition). Mid- and late-log phase cultures produced similar amounts of MMHg, but late stationary phase cultures (both under early and late Hg addition conditions) produced up to {approx}3x more MMHg, indicating the potential importance of growth phase in studies of MMHg production.

  11. Bacterial Growth Phase Influences Methylmercury Production by the Sulfate-Reducing Bacterium Desulfovibrio desulfuricans ND132

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Abir [ORNL; Brooks, Scott C [ORNL; Miller, Carrie L [ORNL; Mosher, Jennifer J [ORNL; Yin, Xiangping Lisa [ORNL; Drake, Meghan M [ORNL

    2011-01-01

    The effect of bacterial growth phase is an aspect of mercury (Hg) methylation that previous studies have not investigated in detail. Here we consider the effect of growth phase (mid-log, late-log and late stationary phase) on Hg methylation by the known methylator Desulfovibrio desulfuricans ND132. We tested the addition of Hg alone (chloride-complex), Hg with Suwannee River natural organic matter (SRNOM) (unequilibrated), and Hg equilibrated with SRNOM on monomethylmercury (MMHg) production by ND132 over a growth curve in pyruvate fumarate media. This NOM did not affect MMHg production even under very low Hg: SRNOM ratios, where Hg binding is predicted to be dominated by high energy sites. Adding Hg or Hg NOM to growing cultures 24 h before sampling (late addition) resulted in ~2 greater net fraction of Hg methylated than for comparably aged cultures exposed to Hg from the initial culture inoculation (early addition). Mid-and late-log phase cultures produced similar amounts of MMHg, but late stationary phase cultures (both under early and late Hg addition conditions) produced up to ~3 more MMHg, indicating the potential importance of growth phase in studies of MMHg production.

  12. Influence of accompanying substances of hemp fibres on their electric resistance

    Directory of Open Access Journals (Sweden)

    Pejić Biljana

    2006-01-01

    Full Text Available Hemp fibres belong to the group of natural, cellulose bast fibres. These fibres have exceptional properties such as: antimicrobial effect, absence of allergy effect, extraordinary sorption properties, good electro-physical properties (small static electricity in regard to other cellulose fibres as well as high values of breaking strength (the natural fibre with the highest strength. However, hemp fibres have some defects: heterogeneous chemical composition, large quantity of accompanying substances (lignin pectins, waxes and unsatisfactory fineness and eveness. It is possible to a great extent to eliminate or reduce, the defects of hemp fibres by of appropriate modification treatments. In order to determine the appropriate modification treatment of hemp fibres, the dependences between the chemical composition, fineness and electric resistance of hemp fibres were presented in this paper. In the experimental part of the paper, by the application of a procedure for the determination of the chemical composition, the accompanying supstances of hemp fibres were gradually removed. After each phase some fibrous substrates were separated. After that the fineness and electric resistance were determined. This experiment was conducted in order to define the influence of each component of hemp fibres on the fineness and electric resistance. In this paper, hemp fibres were modified by an aqueous solution of sodium hydroxide, under different conditions of modification. The influence of modification conditions on the fineness and electric resistance were studied.

  13. [Application of biodegradable plastic film to reduce plastic film residual pollution in Chinese agriculture].

    Science.gov (United States)

    Yan, Changrong; He, Wenqing; Xue, Yinghao; Liu, Enke; Liu, Qin

    2016-06-25

    Plastic film has become an important agriculture production material in recent years. Over the past three decades, the amount and application area of plastic film have increased steadily, and in 2014, which are 1.4 million tons and more than 180 million hm² respectively. It plays a key role for ensuring the supply of agricultural goods in China. Meanwhile, plastic film residual pollution becomes more and more serious, and in some regions, the amount of plastic film residues has reached over 250 kg/hm². In part of the Northwest region, soil structure of farmland has been destroyed by plastic film residues and then crop growth and farming operations were suppressed. It is recognized as a good choice to replace plastic film with biodegradable plastic film, an effective measure to solve the plastic film residue pollution. Now, it is in a critical stage of study and assessment of biodegradable plastic film in China and fortunately some biodegradable plastic films show effects in the production of potatoes, peanuts and tobacco. Overall, a series of challenges has still been faced by the biodegradable plastic film, mainly including improving the quality of biodegradable plastic products, such as tensile strength, flexibility, improving the controllability of rupture and degradation, enhancing the ability of increasing soil temperature and preserving soil moisture, and to satisfy the demand of crops production with mulching. In addition, it is essential to reduce the cost of the biodegradable film and promote the application of biodegradable film on large-scale. With the development of biodegradable plastic technology and agricultural production environment, the application of the biodegradable film will have a good future.

  14. Material properties of plasticized hardwood xylans for potential application as oxygen barrier films.

    Science.gov (United States)

    Gröndahl, Maria; Eriksson, Lisa; Gatenholm, Paul

    2004-01-01

    Free films based on glucuronoxylan isolated from aspen wood were prepared by casting from aqueous solutions and drying in a controlled environment. Addition of xylitol or sorbitol facilitated film formation and thus examination of the material properties of these films. The mechanical properties of the films were evaluated using tensile testing and dynamic mechanical analysis in a controlled ambient relative humidity. The strain at break increased, and the stress at break and Young's modulus of the films decreased with increasing amounts of xylitol and sorbitol due to plasticization. At high amount of plasticizer, it was found that films with xylitol gave lower extensibility. Wide-angle X-ray scattering analysis showed that xylitol crystallized in a distinct phase, which we believe contributes to the more brittle behavior of these films. The effect of the plasticizers on the glass transition temperature was determined using dynamic mechanical analysis and differential scanning calorimetry. An increased amount of plasticizer shifted the glass transition to lower temperatures. The effect of moisture on the properties of plasticized films was investigated using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. Sorption isotherms showed a transition from type II to type III when adding plasticizer. The films showed low oxygen permeability and thus have a potential application in food packaging.

  15. Fatigue Crack Propagation Under Variable Amplitude Loading Analyses Based on Plastic Energy Approach

    Directory of Open Access Journals (Sweden)

    Sofiane Maachou

    2014-04-01

    Full Text Available Plasticity effects at the crack tip had been recognized as “motor” of crack propagation, the growth of cracks is related to the existence of a crack tip plastic zone, whose formation and intensification is accompanied by energy dissipation. In the actual state of knowledge fatigue crack propagation is modeled using crack closure concept. The fatigue crack growth behavior under constant amplitude and variable amplitude loading of the aluminum alloy 2024 T351 are analyzed using in terms energy parameters. In the case of VAL (variable amplitude loading tests, the evolution of the hysteretic energy dissipated per block is shown similar with that observed under constant amplitude loading. A linear relationship between the crack growth rate and the hysteretic energy dissipated per block is obtained at high growth rates. For lower growth rates values, the relationship between crack growth rate and hysteretic energy dissipated per block can represented by a power law. In this paper, an analysis of fatigue crack propagation under variable amplitude loading based on energetic approach is proposed.

  16. From Modeling of Plasticity in Single-Crystal Superalloys to High-Resolution X-rays Three-Crystal Diffractometer Peaks Simulation

    Science.gov (United States)

    Jacques, Alain

    2016-12-01

    The dislocation-based modeling of the high-temperature creep of two-phased single-crystal superalloys requires input data beyond strain vs time curves. This may be obtained by use of in situ experiments combining high-temperature creep tests with high-resolution synchrotron three-crystal diffractometry. Such tests give access to changes in phase volume fractions and to the average components of the stress tensor in each phase as well as the plastic strain of each phase. Further progress may be obtained by a new method making intensive use of the Fast Fourier Transform, and first modeling the behavior of a representative volume of material (stress fields, plastic strain, dislocation densities…), then simulating directly the corresponding diffraction peaks, taking into account the displacement field within the material, chemical variations, and beam coherence. Initial tests indicate that the simulated peak shapes are close to the experimental ones and are quite sensitive to the details of the microstructure and to dislocation densities at interfaces and within the soft γ phase.

  17. Richtmyer-Meshkov instability in elastic-plastic media

    Science.gov (United States)

    Piriz, Antonio R.; López Cela, Juan J.; Tahir, Naeem A.; Hoffmann, Dieter H. H.

    2008-04-01

    Hydrodynamic instabilities are of great importance in the LAPLAS (Laboratory of Planetary Sciences) experiment that is being designed for the study of high energy density states of matter in the framework of the FAIR projectDuring the implosion of the LAPLAS cylindrical target Richtmyer-Meshkov (RM) instability occurs when a shock is launched into a material pusher with elastic and plastic properties that determines the physics of the instability evolution. We have studied the evolution of the interface from which the shock is launched as a consequence of the RM instability. For this we have developed an analytical model and we have performed two-dimensional numerical simulations in order to validate the model. Model and simulations show the asymptotic stability state in which the interface oscillates elastically around a mean value higher than the initial perturbation amplitude. Such a mean value is determined by an initial plastic phase. Applications to the measurement of the yield strength of materials under extreme conditions are foreseen.

  18. Secondary atomic effects accompanying nuclear transitions

    International Nuclear Information System (INIS)

    Walen, R.J.; Briancon, C.

    1975-01-01

    Some consequences of the production of inner-shell vacancies in γ-ray internal conversion are considered and internal ionization or shakeoff accompanying β decay and nuclear electron capture are discussed

  19. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  20. Pigmentary glaucoma accompanied by Usher syndrome.

    Science.gov (United States)

    Koucheki, Behrooz; Jalali, Kamran Hodjat

    2012-08-01

    To report a case of pigmentary glaucoma (PG) accompanied by Usher syndrome. Case report. The results were presented after standard ocular examination, visual field test, anterior segment and fundus photography, electroretinography, and otolaryngology consultation were conducted. Typical retinitis pigmentosa, flat electroretinography, congenital sensorineural hearing loss, high intraocular pressure, Krukenberg spindle, iris concavity, radial iris transillumination defect, severe pigment deposition on the trabecular meshwork, and glaucomatous optic nerve damage were indicative of PG accompanied by Usher syndrome. In some rare cases, PG may coexist with Usher syndrome. Common findings of Usher syndrome, including night blindness, impaired vision, visual field defects, and retinal changes may distract the clinician from considering the diagnosis of glaucoma. Such association should be borne in mind to make a timely diagnosis and treatment possible.

  1. Plastics in the Marine Environment.

    Science.gov (United States)

    Law, Kara Lavender

    2017-01-03

    Plastics contamination in the marine environment was first reported nearly 50 years ago, less than two decades after the rise of commercial plastics production, when less than 50 million metric tons were produced per year. In 2014, global plastics production surpassed 300 million metric tons per year. Plastic debris has been detected worldwide in all major marine habitats, in sizes from microns to meters. In response, concerns about risks to marine wildlife upon exposure to the varied forms of plastic debris have increased, stimulating new research into the extent and consequences of plastics contamination in the marine environment. Here, I present a framework to evaluate the current understanding of the sources, distribution, fate, and impacts of marine plastics. Despite remaining knowledge gaps in mass budgeting and challenges in investigating ecological impacts, the increasing evidence of the ubiquity of plastics contamination in the marine environment, the continued rapid growth in plastics production, and the evidence-albeit limited-of demonstrated impacts to marine wildlife support immediate implementation of source-reducing measures to decrease the potential risks of plastics in the marine ecosystem.

  2. Plastics in the Marine Environment

    Science.gov (United States)

    Law, Kara Lavender

    2017-01-01

    Plastics contamination in the marine environment was first reported nearly 50 years ago, less than two decades after the rise of commercial plastics production, when less than 50 million metric tons were produced per year. In 2014, global plastics production surpassed 300 million metric tons per year. Plastic debris has been detected worldwide in all major marine habitats, in sizes from microns to meters. In response, concerns about risks to marine wildlife upon exposure to the varied forms of plastic debris have increased, stimulating new research into the extent and consequences of plastics contamination in the marine environment. Here, I present a framework to evaluate the current understanding of the sources, distribution, fate, and impacts of marine plastics. Despite remaining knowledge gaps in mass budgeting and challenges in investigating ecological impacts, the increasing evidence of the ubiquity of plastics contamination in the marine environment, the continued rapid growth in plastics production, and the evidence—albeit limited—of demonstrated impacts to marine wildlife support immediate implementation of source-reducing measures to decrease the potential risks of plastics in the marine ecosystem.

  3. Plasticity induced phase transformation in molecular crystals

    OpenAIRE

    Koslowski, Marisol

    2014-01-01

    Solid state amorphization (SSA) can be achieved in crystalline materials including metal alloys, intermetallics, semiconductors, minerals and molecular crystals. Even though the mechanisms may differ in different materials, the crystalline to amorphous transformation occurs when the crystal reaches a metastable state in which its free energy is higher than that of the amorphous phase. SSA is observed in metal alloys because of interdiffusion of the crystalline elements during mechanical milli...

  4. Selection of polychlorinated plastics in plastic waste by X-ray fluorescence method

    International Nuclear Information System (INIS)

    Kumasaki, H.; Shinozaki, Y.

    1979-01-01

    The X-ray fluorescence method using a small source of 55 Fe was examined and found to be applicable for the selection of polychlorinated plastics from plastic waste in model areas in Tokyo designated for investigating their content in the waste. The weight ratios of soft and hard polychlorinated plastics to the total plastic waste estimated by this method were found to be 15.6% and 0.29% respectively. These values agree well with the results obtained with the Beilstein method. (author)

  5. Toxicological Threats of Plastic

    Science.gov (United States)

    Plastics pose both physical (e.g., entanglement, gastrointestinal blockage, reef destruction) and chemical threats (e.g., bioaccumulation of the chemical ingredients of plastic or toxic chemicals sorbed to plastics) to wildlife and the marine ecosystem.

  6. Rats' learned preferences for flavors encountered early or late in a meal paired with the postingestive effects of glucose.

    Science.gov (United States)

    Myers, Kevin P; Whitney, Margaret C

    2011-03-28

    Rats learn to prefer flavors that are followed by postingestive effects of nutrients. This experiment investigated whether the timing of a flavor (specifically, in the first or second half of the meal) influences learning about that flavor. Stronger learning about earlier or later flavors would indicate when the rewarding postingestive effects of nutrients are sensed. Rats with intragastric (IG) catheters drank saccharin-sweetened, calorically-dilute solutions with distinct flavors added, accompanied by IG infusion of glucose (+sessions) or water (-sessions). In both types of sessions, an "Early" flavor was provided for the first 8 min and a "Late" flavor for the last 8 min. Thus, rats were trained with Early(+) and Late(+) in high-calorie meals, and Early(-) and Late(-) in low-calorie meals. Strength of the learned preference for Early(+) and Late(+) was then assessed in a series of two-bottle choice tests between Early(+) vs. Early(-), Late(+) vs. Late(-), Early(+) vs. Late(+), and Early(-) vs. Late(-). Rats preferred both Early(+) and Late(+) over the respective (-) flavors. But Early(+) was only preferred when rats were tested hungry. Late(+) was preferred when rats were tested hungry or recently satiated. This indicates qualitatively different associations learned about flavors at different points in the meal. While not supporting the idea that postingestive effects become most strongly associated with later-occurring ("dessert") flavors, it does suggest a reason dessert flavors may remain attractive in the absence of hunger. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. HZE dosimetry in space using plastic track detectors

    CERN Document Server

    Kopp, J; Reitz, G; Enge, W

    1999-01-01

    Plastic nuclear track detectors were used to measure the contribution of High charge Z and energy E (HZE) particles to the radiation exposure of manned space missions. Results from numerous space missions in the orbit planned for the International Space Station are compared. The measurements cover the declining phase of the last solar cycle during the past 7 years and various shielding conditions inside the US Space Shuttle and the Russian MIR-station.

  8. Vegetative and reproductive evaluation of hot peppers under different plastic mulches in poly/plastic tunnel

    International Nuclear Information System (INIS)

    Iqbal, Q.; Amjad, M.; Ahmad, R.

    2009-01-01

    Since the beginning of civilization, the man has developed technologies to increase the efficiency of food production. The use of plastic mulch in commercial vegetable production is one of these traditional techniques that have been used for centuries. Studies were conducted to assess the efficacy of plastic mulch on growth and yield of two hot pepper hybrids, viz. Sky Red and Maha in poly/plastic tunnel. The treatments were black plastic mulch, clear plastic mulch and bare soil as control. Both hot pepper hybrids mulched with black plastic showed significantly better vegetative growth (plant height, leaf area etc) and fruit yield. Clear plastic mulch significantly increased soil temperature and reduced the number of days to first flower than black plastic mulch and bare soil. However, fruit yield was higher by 39.56 and 36.49% respectively in both hybrids when they were grown on black and clear plastic mulch as compared to bare soil. Overall results indicated that the use of plastic mulch is an ideal option to maximize hot pepper productivity as well as to extend their production season in poly/plastic tunnels. (author)

  9. Effect of Plastic Deformation on the Corrosion Behavior of a Super-Duplex Stainless Steel

    Science.gov (United States)

    Renton, Neill C.; Elhoud, Abdu M.; Deans, William F.

    2011-04-01

    The role of plastic deformation on the corrosion behavior of a 25Cr-7Ni super-duplex stainless steel (SDSS) in a 3.5 wt.% sodium chloride solution at 90 °C was investigated. Different levels of plastic strain between 4 and 16% were applied to solution annealed tensile specimens and the effect on the pitting potential measured using potentiodynamic electrochemical techniques. A nonlinear relationship between the pitting potential and the plastic strain was recorded, with 8 and 16% causing a significant reduction in average E p, but 4 and 12% causing no significant change when compared with the solution-annealed specimens. The corrosion morphology revealed galvanic interaction between the anodic ferrite and the cathodic austenite causing preferential dissolution of the ferrite. Mixed potential theory and the changing surface areas of the two phases caused by the plastic deformation structures explain the reductions in pitting potential at certain critical plastic strain levels. End-users and manufacturers should evaluate the corrosion behavior of specific cold-worked duplex and SDSSs using their as-produced surface finishes assessing in-service corrosion performance.

  10. Transgenerational plasticity as an important mechanism affecting response of clonal species to changing climate.

    Science.gov (United States)

    Münzbergová, Zuzana; Hadincová, Věroslava

    2017-07-01

    In spite of the increasing number of studies on the importance of transgenerational plasticity for species response to novel environments, its effects on species ability to respond to climate change are still largely unexplored. We study the importance of transgenerational plasticity for response of a clonal species Festuca rubra . Individuals from four natural populations representing two levels of temperature and two levels of precipitation were cultivated in four growth chambers that simulate the temperature and precipitation of origin of the populations (maternal phase). Each population was represented in each growth chamber. After 6 months, single young ramets of these plants were reshuffled among the growth chambers and let to grow for additional 2 months (offspring phase). The results show that transgenerational effects (i.e., maternal phase conditions) significantly modify species response to novel climates, and the direction and intensity of the response depend on the climate of origin of the plants. For traits related to recourse acquisition, the conditions of maternal phase, either alone or in interaction mainly with climate of origin, had stronger effect than the conditions of cultivation. Overall, the maternal climate interacted more intensively with the climate of origin than with the offspring climate. The direction of the effect of the maternal climate was of different directions and intensities depending on plant origin and trait studied. The data demonstrated strong significant effects of conditions during maternal phase on species response to novel climates. These transgenerational affects were, however, not adaptive. Still, transgenerational plasticity may be an important driver of species response to novel conditions across clonal generations. These effects thus need to be carefully considered in future studies exploring species response to novel climates. This will also have strong effects on species performance under increasingly variable

  11. 1,2,4-Triazolium perfluorobutanesulfonate as an archetypal pure protic organic ionic plastic crystal electrolyte for all-solid-state fuel cells

    DEFF Research Database (Denmark)

    Luo, Jiangshui; Jensen, Annemette Hindhede; Brooks, Neil R.

    2015-01-01

    1,2,4-Triazolium perfluorobutanesulfonate (1), a novel, pure protic organic ionic plastic crystal (POIPC) with a wide plastic crystalline phase, has been explored as a proof-of-principle anhydrous proton conductor for all-solid-state high temperature hydrogen/air fuel cells. Its physicochemical p...

  12. Interaction between vegetable oil based plasticizer molecules and polyvinyl chloride, and their plasticization effect

    Science.gov (United States)

    Haryono, Agus; Triwulandari, Evi; Jiang, Pingping

    2017-01-01

    Plasticizer molecules are low molecular weight compounds that are widely used in polymer industries especially in polyvinyl chloride (PVC) resin. As an additive in PVC resin, the important role of plasticizer molecules is to improve the flexibility and processability of PVC by lowering the glass transition temperature (Tg). However, the commercial plasticizer like di(2-ethylhexyl)phthalate (DEHP) is known to cause liver cancer, at least in laboratory rats. DEHP can leach out from PVC into blood, certain drug solutions and fatty foods, which has been detected in the bloodstream of patients undergoing transfusion. Vegetable oil based plasticizers have some attractive properties such as non-toxic, bio-degradable, good heat and light stability, renewable resources, and environmentally friendly. Here we discussed the main results and development of vegetable oil based plasticizer, and especially palm oil based plasticizer. The interaction between plasticizer and polymer was discussed from the properties of the plasticized polymeric material.

  13. Late Jurassic – early Cretaceous inversion of rift structures, and linkage of petroleum system elements across post-rift unconformity, U.S. Chukchi Shelf, arctic Alaska

    Science.gov (United States)

    Houseknecht, David W.; Connors, Christopher D.

    2015-01-01

    Basin evolution of the U.S. Chukchi shelf involved multiple phases, including Late Devonian–Permian rifting, Permian–Early Jurassic sagging, Late Jurassic–Neocomian inversion, and Cretaceous–Cenozoic foreland-basin development. The focus of ongoing exploration is a petroleum system that includes sag-phase source rocks; inversion-phase reservoir rocks; structure spanning the rift, sag, and inversion phases; and hydrocarbon generation during the foreland-basin phase.

  14. Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

    Science.gov (United States)

    Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

    2016-02-05

    Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

  15. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

  16. Cdc7 is required throughout the yeast S phase to activate replication origins.

    Science.gov (United States)

    Donaldson, A D; Fangman, W L; Brewer, B J

    1998-02-15

    The long-standing conclusion that the Cdc7 kinase of Saccharomyces cerevisiae is required only to trigger S phase has been challenged by recent data that suggests it acts directly on individual replication origins. We tested the possibility that early- and late-activated origins have different requirements for Cdc7 activity. Cells carrying a cdc7(ts) allele were first arrested in G1 at the cdc7 block by incubation at 37 degrees C, and then were allowed to enter S phase by brief incubation at 23 degrees C. During the S phase, after return to 37 degrees C, early-firing replication origins were activated, but late origins failed to fire. Similarly, a plasmid with a late-activated origin was defective in replication. As a consequence of the origin activation defect, duplication of chromosomal sequences that are normally replicated from late origins was greatly delayed. Early-replicating regions of the genome duplicated at approximately their normal time. The requirements of early and late origins for Cdc7 appear to be temporally rather than quantitatively different, as reducing overall levels of Cdc7 by growth at semi-permissive temperature reduced activation at early and late origins approximately equally. Our results show that Cdc7 activates early and late origins separately, with late origins requiring the activity later in S phase to permit replication initiation.

  17. Localization of plastic yield and fracture mechanism in high-strength niobium alloy with ultra-fine particles of non-metallic phase

    International Nuclear Information System (INIS)

    Tyumentsev, A.N.; Gonchikov, V.Ch.; Korotaev, A.D.; Pinzhin, Yu.P.; Tyumentseva, S.F.

    1989-01-01

    The regularities of localization of plastic flow in high-strength dispersion-strengthened niobium alloy are studied. On the basis of investigations of the microstructure of strain localization zones the mechanism of stability losses of plastic flow including, the processes of diffusion of nonequilibrium vacancies in fields of nonuniform stresses, is proposed. The role of diffuse strain mechanisms during reorientation of the crystalline lattice is discussed. The regularities of fracture of high-strength alloy under conditions of rotational-shift instability of plastic flow are investigated

  18. Effects of B2 precipitate size on transformation-induced plasticity of Cu–Zr–Al glassy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C.N. [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Huang, J.C., E-mail: jacobc@mail.nsysu.edu.tw [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Li, J.B.; Jang, J.S.C. [Institute of Materials Science and Engineering, Department of Mechanical Engineering, National Central University, Chung-Li, Taiwan, ROC (China); Lin, C.H. [Department of Mechanical and Electromechanical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Nieh, T.G. [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States)

    2014-03-25

    Highlights: • This paper addresses the effects of the CuZr B2 size and distribution on plasticity. • There is a critical size to induce the martensitic/twinning transformation. • An analytic model based on melt flow dynamics is settled. -- Abstract: To demonstrate the effect of processing on the microstructure and subsequent mechanical property of bulk metallic glasses, we prepared two alloys, Cu{sub 47.5}Zr{sub 47.5}Al{sub 5} and Cu{sub 47.5}Zr{sub 48}Al{sub 4}Co{sub 0.5}, using two different designs of suction mold – one with a sharp inlet and one with a blunt inlet. The two alloys have been demonstrated previously to be ductile via phase transformation of the B2 phase and twin formation during plastic deformation. Microstructures of the as-cast as well plastically deformed samples, in particular, the size and distribution of the B2 phase, were examined using X-ray diffraction, scanning and transmission electron microscopy. Compressive tests were conducted on samples cast by different molds and their properties were found to closely correlate with the B2 morphology. Fluid dynamics during suction casting was also analyzed. Effects of Vena contracta, flow velocity, and Reynolds number were discussed and compared favorably with experimental observations.

  19. Abiotic degradation of plastic films

    Science.gov (United States)

    Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

    2017-01-01

    Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

  20. Plasticity characteristic obtained by indentation

    International Nuclear Information System (INIS)

    Mil'man, Yu.V.; Chugunova, S.I.; Goncharova, I.V.

    2011-01-01

    Methods for determination plasticity characteristic δH in the measurement of hardness and nanohardness are considered. Parameter δH characterizes the plasticity of a material by the part of plastic deformation in the total elastic-plastic deformation. The value of δH is defined for metals with different types of crystal lattice, covalent and partially covalent crystals, intermetallics, metallic glasses and quasicrystals. It is discussed the dependence of the plasticity characteristic δH on structural factors and temperature. Parameter δH allows to analyze and compare the plasticity of materials which are brittle at standard mechanical tests. The combination of hardness H, as the strength characteristic, and the plasticity characteristic δH makes possible the better characterization of mechanical behavior of materials than only the hardness H. The examples of plasticity characteristic δH application are represented.

  1. Sparing of descending axons rescues interneuron plasticity in the lumbar cord to allow adaptive learning after thoracic spinal cord injury

    Directory of Open Access Journals (Sweden)

    Christopher Nelson Hansen

    2016-03-01

    Full Text Available This study evaluated the role of spared axons on structural and behavioral neuroplasticity in the lumbar enlargement after a thoracic spinal cord injury (SCI. Previous work has demonstrated that recovery in the presence of spared axons after an incomplete lesion increases behavioral output after a subsequent complete spinal cord transection (TX. This suggests that spared axons direct adaptive changes in below-level neuronal networks of the lumbar cord. In response to spared fibers, we postulate that lumbar neuron networks support behavioral gains by preventing aberrant plasticity. As such, the present study measured histological and functional changes in the isolated lumbar cord after complete TX or incomplete contusion (SCI. To measure functional plasticity in the lumbar cord, we used an established instrumental learning paradigm. In this paradigm, neural circuits within isolated lumbar segments demonstrate learning by an increase in flexion duration that reduces exposure to a noxious leg shock. We employed this model using a proof-of-principle design to evaluate the role of sparing on lumbar learning and plasticity early (7 days or late (42 days after midthoracic SCI in a rodent model. Early after SCI or TX at 7d, spinal learning was unattainable regardless of whether the animal recovered with or without axonal substrate. Failed learning occurred alongside measures of cell soma atrophy and aberrant dendritic spine expression within interneuron populations responsible for sensorimotor integration and learning. Alternatively, exposure of the lumbar cord to a small amount of spared axons for 6 weeks produced near-normal learning late after SCI. This coincided with greater cell soma volume and fewer aberrant dendritic spines on interneurons. Thus, an opportunity to influence activity-based learning in locomotor networks depends on spared axons limiting maladaptive plasticity. Together, this work identifies a time dependent interaction between

  2. LATE CREATACEOUS-CENOZOIC SEDIMENTS OF THE BAIKAL RIFT BASIN AND CHANGING NATURAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Viktor D. Mats

    2010-01-01

    Full Text Available The late Cretaceous-Cenozoic sediments of fossil soils and weathering crusts of the Baikal rift have been subject to long-term studies. Based on our research results, it is possible to distinguish the following litho-stratigraphic complexes which are related to particular stages of the rift development: the late Cretaceous–early Oligocene (crypto-rift Arheo-baikalian, the late Oligocene–early Pliocene (ecto-rift early orogenic Pra-baikalian, and the late Pliocene-Quaternary (ecto-rift late orogenic Pra-baikalian – Baikalian complexes. Changes of weathering modes (Cretaceous-quarter, soil formation (Miocene-quarter and differences of precipitation by vertical and lateral stratigraphy are analysed with regard to specific features of climate, tectonics and facial conditions of sedimentation. Tectonic phases are defined in the Cenozoic period of the Pribaikalie.

  3. Critical thinking of student nurses during clinical accompaniment.

    Science.gov (United States)

    Uys, B Y; Meyer, S M

    2005-08-01

    The purpose of this study was to investigate the methods of clinical accompaniment used by clinical facilitators in practice. The findings of the study also reflected facilitators' perceptions regarding critical thinking and the facilitation thereof. A quantitative research design was used. A literature study was conducted to identify the methods of accompaniment that facilitate critical thinking. Data was collected by means of a questionnaire developed for that purpose. Making a content-related validity judgment, and involving seven clinical facilitators in an academic institution, ensured the validity of the questionnaire. The results of the study indicated that various clinical methods of accompaniment were used. To a large extent, these methods correlated with those discussed in the literature review. The researcher further concluded that the concepts 'critical thinking' and 'facilitation' were not interpreted correctly by the respondents, and would therefore not be implemented in a proper manner in nursing practice. Furthermore, it seemed evident that tutor-driven learning realised more often than student-driven learning. In this regard, the requirement of outcomes-based education was not satisfied. The researcher is therefore of the opinion that a practical programme for the development of critical thinking skills during clinical accompaniment must be developed within the framework of outcomes-based education.

  4. Critical thinking of student nurses during clinical accompaniment

    Directory of Open Access Journals (Sweden)

    BY Uys

    2005-09-01

    Full Text Available The purpose of this study was to investigate the methods of clinical accompaniment used by clinical facilitators in practice. The findings of the study also reflected facilitators’ perceptions regarding critical thinking and the facilitation thereof. A quantitative research design was used. A literature study was conducted to identify the methods of accompaniment that facilitate critical thinking. Data was collected by means of a questionnaire developed for that purpose. Making a content-related validity judgment, and involving seven clinical facilitators in an academic institution, ensured the validity of the questionnaire. The results of the study indicated that various clinical methods of accompaniment were used. To a large extent, these methods correlated with those discussed in the literature review. The researcher further concluded that the concepts ‘critical thinking’ and ‘facilitation’ were not interpreted correctly by the respondents, and would therefore not be implemented in a proper manner in nursing practice. Furthermore, it seemed evident that tutor-driven learning realised more often than student-driven learning. In this regard, the requirement of outcomes-based education was not satisfied. The researcher is therefore of the opinion that a practical programme for the development of critical thinking skills during clinical accompaniment must be developed within the framework of outcomes-based education.

  5. IUE and Einstein survey of late-type giant and supergiant stars and the dividing line

    Science.gov (United States)

    Haisch, Bernhard M.; Bookbinder, Jay A.; Maggio, A.; Vaiana, G. S.; Bennett, Jeffrey O.

    1990-01-01

    Results are presented on an IUE UV survey of 255 late-type G, K, and M stars, complementing the Maggio et al. (1990) Einstein X-ray survey of 380 late-type stars. The large data sample of X-ray and UV detections make it possible to examine the activity relationship between the X-ray and the UV emissions. The results confirm previous finding of a trend involving a steeply-dropping upper envelope of the transition region line fluxes, f(line)/f(V), as the dividing line is approached. This suggests that a sharp decrease in maximum activity accompanies the advancing spectral type, with the dividing line corresponding to this steep gradient region. The results confirm the rotation-activity connection for stars in this region of the H-R diagram.

  6. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-thomsen, Søren; Ditlevsen, Ove Dalager

    1996-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

  7. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-Thomsen, S.; Ditlevsen, Ove Dalager

    1999-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

  8. A signature of epithelial-mesenchymal plasticity and stromal activation in primary tumor modulates late recurrence in breast cancer independent of disease subtype.

    Science.gov (United States)

    Cheng, Qing; Chang, Jeffrey T; Gwin, William R; Zhu, Jun; Ambs, Stefan; Geradts, Joseph; Lyerly, H Kim

    2014-07-25

    Despite improvements in adjuvant therapy, late systemic recurrences remain a lethal consequence of both early- and late-stage breast cancer. A delayed recurrence is thought to arise from a state of tumor dormancy, but the mechanisms that govern tumor dormancy remain poorly understood. To address the features of breast tumors associated with late recurrence, but not confounded by variations in systemic treatment, we compiled breast tumor gene expression data from 4,767 patients and established a discovery cohort consisting of 743 lymph node-negative patients who did not receive systemic neoadjuvant or adjuvant therapy. We interrogated the gene expression profiles of the 743 tumors and identified gene expression patterns that were associated with early and late disease recurrence among these patients. We applied this classification to a subset of 46 patients for whom expression data from microdissected tumor epithelium and stroma was available, and identified a distinct gene signature in the stroma and also a corresponding tumor epithelium signature that predicted disease recurrence in the discovery cohort. This tumor epithelium signature was then validated as a predictor for late disease recurrence in the entire cohort of 4,767 patients. We identified a novel 51-gene signature from microdissected tumor epithelium associated with late disease recurrence in breast cancer independent of the molecular disease subtype. This signature correlated with gene expression alterations in the adjacent tumor stroma and describes a process of epithelial to mesenchymal transition (EMT) and tumor-stroma interactions. Our findings suggest that an EMT-related gene signature in the tumor epithelium is related to both stromal activation and escape from disease dormancy in breast cancer. The presence of a late recurrence gene signature in the primary tumor also suggests that intrinsic features of this tumor regulate the transition of disseminated tumor cells into a dormant phenotype with

  9. ENVIRONMENTAL ISSUE-PLASTIC

    OpenAIRE

    Sunita Shakle

    2017-01-01

    Polythene is the most common plastic, the annual global production is approximately 60 million tones, and its primary use is in packing. Plastic bags pollute soil and waters and kill thousands of marine generalize plastic bags are not biodegradable they clog water ways, spoil the land scape and end up in landfills. Where they may take 1000 year or more to break down into ever smaller particals that continue to pollution the soil and water.

  10. Finite element modeling of indentation-induced superelastic effect using a three-dimensional constitutive model for shape memory materials with plasticity

    International Nuclear Information System (INIS)

    Zhang, Yijun; Cheng, Yang-Tse; Grummon, David S.

    2007-01-01

    Indentation-induced shape memory and superelastic effects are recently discovered thermo-mechanical behaviors that may find important applications in many areas of science and engineering. Theoretical understanding of these phenomena is challenging because both martensitic phase transformation and slip plasticity exist under complex contact loading conditions. In this paper, we develop a three-dimensional constitutive model of shape memory alloys with plasticity. Spherical indentation-induced superelasticity in a NiTi shape memory alloy was simulated and compared to experimental results on load-displacement curves and recovery ratios. We show that shallow indents have complete recovery upon unloading, where the size of the phase transformation region is about two times the contact radius. Deep indents have only partial recovery when plastic deformation becomes more prevalent in the indent-affected zone

  11. Predictors of severe late radiotherapy-related toxicity after hyperfractionated radiotherapy with or without concomitant cisplatin in locally advanced head and neck cancer. Secondary retrospective analysis of a randomized phase III trial (SAKK 10/94)

    International Nuclear Information System (INIS)

    Ghadjar, Pirus; Simcock, Mathew; Zimmermann, Frank; Betz, Michael; Bodis, Stephan; Bernier, Jacques; Studer, Gabriela; Aebersold, Daniel M.

    2012-01-01

    Background and purpose: This secondary analysis was performed to identify predictive factors for severe late radiotherapy (RT)-related toxicity after treatment with hyperfractionated RT +/− concomitant cisplatin in locally advanced head and neck cancer. Materials and methods: Patients were retrospectively analyzed from the previously reported randomized phase III trial: SAKK 10/94. Severe late RT-related toxicity was defined as late RTOG ⩾ grade 3 toxicity starting 3 months after end of RT and/or potential treatment-related death within 3 years of randomization. Results: Two hundred and thirteen randomized patients were analyzed; 84 (39%) experienced severe late RT-related toxicity. With median follow-up of 9.7 years (range, 0.4–15.4 years), median time to severe late RT-related toxicity was 9.6 years. In the univariate Cox proportional hazards model the following variables were associated with severe late RT-related toxicity: advanced N-classification (p < 0.001); technically unresectable disease (p = 0.04); weight loss ratio (p = 0.003); supportive measures (p = 0.009) and severe acute dysphagia (p = 0.001). In the subsequent multivariate analysis all variables except use of supportive measures remained statistically significant. Conclusions: Chemotherapy did not appear to affect severe late RT-related toxicity, but advanced N-classification, technically unresectable disease, weight loss ratio, and severe acute dysphagia were independent predictive factors for severe late RT-related toxicity.

  12. Motor Skill Learning Is Associated with Phase-Dependent Modifications in the Striatal cAMP/PKA/DARPP-32 Signaling Pathway in Rodents.

    Directory of Open Access Journals (Sweden)

    Yu Qian

    Full Text Available Abundant evidence points to a key role of dopamine in motor skill learning, although the underlying cellular and molecular mechanisms are still poorly understood. Here, we used a skilled-reaching paradigm to first examine changes in the expression of the plasticity-related gene Arc to map activity in cortico-striatal circuitry during different phases of motor skill learning in young animals. In the early phase, Arc mRNA was significantly induced in the medial prefrontal cortex (mPFC, cingulate cortex, primary motor cortex, and striatum. In the late phase, expression of Arc did not change in most regions, except in the mPFC and dorsal striatum. In the second series of experiments, we studied the learning-induced changes in the phosphorylation state of dopamine and cAMP-regulated phosphoprotein, 32k Da (DARPP-32. Western blot analysis of the phosphorylation state of DARPP-32 and its downstream target cAMP response element-binding protein (CREB in the striatum revealed that the early, but not late, phase of motor skill learning was associated with increased levels of phospho-Thr34-DARPP-32 and phospho-Ser133-CREB. Finally, we used the DARPP-32 knock-in mice with a point mutation in the Thr34 regulatory site (i.e., protein kinase A site to test the significance of this pathway in motor skill learning. In accordance with our hypothesis, inhibition of DARPP-32 activity at the Thr34 regulatory site strongly attenuated the motor learning rate and skilled reaching performance of mice. These findings suggest that the cAMP/PKA/DARPP-32 signaling pathway is critically involved in the acquisition of novel motor skills, and also demonstrate a dynamic shift in the contribution of cortico-striatal circuitry during different phases of motor skill learning.

  13. Critical thinking of student nurses during clinical accompaniment

    OpenAIRE

    BY Uys; SM Meyer

    2005-01-01

    The purpose of this study was to investigate the methods of clinical accompaniment used by clinical facilitators in practice. The findings of the study also reflected facilitators’ perceptions regarding critical thinking and the facilitation thereof. A quantitative research design was used. A literature study was conducted to identify the methods of accompaniment that facilitate critical thinking. Data was collected by means of a questionnaire developed for that purpose. Making a content-rela...

  14. Nano-Ceramic Coated Plastics

    Science.gov (United States)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (nano-ceramic coatings (TiO2, ZnO) on plastic materials (silicone, Teflon, PET, etc.) that can possess both photocatalytic oxide properties and flexible plastic properties. Processing cost is low and it does not require any expensive equipment investment. Processing can be scalable to current manufacturing infrastructure.

  15. Predicting Residential Exposure to Phthalate Plasticizer Emitted from Vinyl Flooring - A Mechanistic Analysis

    Science.gov (United States)

    A two-room model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring and the evolving gas-phase and adsorbed surface concentrations in a realistic indoor environment. Adsorption isotherms for phthalates and plasticizers on interior ...

  16. Elastic-plastic analysis of AS4/PEEK composite laminate using a one-parameter plasticity model

    Science.gov (United States)

    Sun, C. T.; Yoon, K. J.

    1992-01-01

    A one-parameter plasticity model was shown to adequately describe the plastic deformation of AS4/PEEK (APC-2) unidirectional thermoplastic composite. This model was verified further for unidirectional and laminated composite panels with and without a hole. The elastic-plastic stress-strain relations of coupon specimens were measured and compared with those predicted by the finite element analysis using the one-parameter plasticity model. The results show that the one-parameter plasticity model is suitable for the analysis of elastic-plastic deformation of AS4/PEEK composite laminates.

  17. Performance of molded plastic scintillators

    International Nuclear Information System (INIS)

    Gen, N.S.; Leman, V.E.; Solomonov, V.M.

    1989-01-01

    The performance of molded plastic scintillators is studied. The plastic scintillators studied were formed by transfer molding and intrusion from a scintillation composition consisting of polystyrene and a standard system of luminescent additives: 2 mass % of paraterphenyl + 0.06 mass % 1,4-di-/2-[5-phenyloxazoyly]/benzene and a plasticizer. The combined effect of mechanical load and temperature was studied. The effect of radiation on molded plastic scintillators was studied using gamma radiation from a 60 Co source. The studies show that the main operating characteristics of molded plastic scintillators are on a par with those of polymerized plastic scintillators. At the same time, molded plastic scintillators are superior in thermal stability at temperatures below the glass transition temperature and with respect to their working temperature range

  18. Plastic food packaging and health

    Directory of Open Access Journals (Sweden)

    Raika Durusoy

    2011-02-01

    Full Text Available Plastics have a wide usage in our daily lives. One of their uses is for food packaging and food containers. The aim of this review is to introduce different types of chemicals that can leach from food packaging plastics into foods and cause human exposure and to mention their effects on health. The types of plastics were reviewed under the 13 headings in Turkish Codex Alimentarius and plastics recycling symbols were provided to enable the recognition of the type of plastic when applicable. Chemicals used during the production and that can cause health risks are investigated under the heading of the relevant type of plastic. The most important chemicals from plastic food packaging that can cause toxicity are styrene, 1,3-butadiene, melamine, formaldehyde, acrylamide, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate, vinyl chloride and bisphenol A. These chemicals have endocrine disrupting, carcinogenic and/or development disrupting effects. These chemicals may leach into foods depending on the chemical properties of the plastic or food, temperature during packaging, processing and storage, exposure to UV and duration of storage. Contact with fatty/oily or acidic foods, heating of the food inside the container, or drinking hot drinks from plastic cups, use of old and scratched plastics and some detergents increase the risk of leaching. The use of plastic containers and packaging for food and beveradges should be avoided whenever possible and when necessary, less harmful types of plastic should be preferred. [TAF Prev Med Bull 2011; 10(1.000: 87-96

  19. Dependence of stress-induced omega transition and mechanical twinning on phase stability in metastable β Ti–V alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.L.; Li, L.; Mei, W.; Wang, W.L.; Sun, J., E-mail: jsun@sjtu.edu.cn

    2015-09-15

    Tensile properties and deformation microstructures of a series of binary β Ti–16–22V alloys have been investigated. The results show that the plastic deformation mode changes from the plate-like stress-induced ω phase transformation with a special habit plane of (− 5052){sub ω}//(3 − 3 − 2){sub β} to (332)<113> type deformation twinning with increasing the content of vanadium in the β Ti–16–22 wt.% V alloys. The plate-like stress-induced ω phase has a special orientation relationship with the β phase matrix, i.e., [110]{sub β}//[− 12 − 10]{sub ω}, (3 − 3 − 2){sub β}//(− 5052){sub ω} and (− 55 − 4){sub β}//(30 − 31){sub ω}. The alloys plastically deformed by stress-induced ω phase transformation exhibit relatively higher yield strength than those deformed via (332)<113> type deformation twinning. It can be concluded that the stability of β phase plays a significant role in plastic deformation mode, i.e., stress-induced ω phase transformation or (332)<113> type deformation twinning, which governs the mechanical property of the β Ti–16–22 wt.% V alloys. - Highlights: • Tensile properties and deformed microstructures of β Ti–16–22V alloys were studied. • Stress-induced ω phase transformation and (332)<113> twinning occur in the alloys. • Stability of β phase plays a significant role in plastic deformation mode. • Plastic deformation mode governs the mechanical property of the alloys.

  20. Late replication domains are evolutionary conserved in the Drosophila genome.

    Science.gov (United States)

    Andreyenkova, Natalya G; Kolesnikova, Tatyana D; Makunin, Igor V; Pokholkova, Galina V; Boldyreva, Lidiya V; Zykova, Tatyana Yu; Zhimulev, Igor F; Belyaeva, Elena S

    2013-01-01

    Drosophila chromosomes are organized into distinct domains differing in their predominant chromatin composition, replication timing and evolutionary conservation. We show on a genome-wide level that genes whose order has remained unaltered across 9 Drosophila species display late replication timing and frequently map to the regions of repressive chromatin. This observation is consistent with the existence of extensive domains of repressive chromatin that replicate extremely late and have conserved gene order in the Drosophila genome. We suggest that such repressive chromatin domains correspond to a handful of regions that complete replication at the very end of S phase. We further demonstrate that the order of genes in these regions is rarely altered in evolution. Substantial proportion of such regions significantly coincide with large synteny blocks. This indicates that there are evolutionary mechanisms maintaining the integrity of these late-replicating chromatin domains. The synteny blocks corresponding to the extremely late-replicating regions in the D. melanogaster genome consistently display two-fold lower gene density across different Drosophila species.

  1. Multilevel modeling of micromechanics and phase formation for microstructural evolution of magnetic zones

    International Nuclear Information System (INIS)

    Suwa, Yoshihiro; Aizawa, Tatsuhiko; Takaya, Shigeru; Nagae, Yuji; Aoto, Kazumi

    2005-03-01

    The present research aims at a proposal of theoretical treatise to describe the local phase transformation from austenite to ferrite in the stainless steels under hot cyclic fatigue conditions. In experiments, this local phase transformation is detected as a magnetized region in the non-magnetic matrix after low-cycle fatigue test at the elevated temperature. The theoretical frame proposed here is composed of two methodologies. In the first approach, microstructure evolution with γ → α transformation is described by the phase field method. In the second approach, micromechanical method on the basis of the unit cell modeling is proposed to develop a new micromechanical analysis. The details of two approached are summarized in the following. (1) Phase formation simulation by the phase field method. Most of reports have started that γ-α phase transformation as a creep damage is induced by dechromization, which comes from carbide precipitation around grain boundaries. A new theoretical treatise is proposed for simulating this γ → α transformation in Fe-Cr-Ni system. Stabilities of both phases are investigated for various chemical compositions. Furthermore, in order to investigate dechromization phenomena in Fe-Cr-Ni-C system, a new theoretical frame is also proposed to handle an interstitial element in phase field method. (2) Low cycle fatigue elasto-plastic analysis by the unit-cell modeling. In experiments, the magnetized zones are generated to distribute at the vicinity of the hard, delta-phase inclusion in the austenitic matrix. The cumulative plastic region advances in the surroundings of this hard inclusion with increasing the number of cycles in the controlled strain range. This predicted profile of cumulative plastic regions corresponds to the experimentally measured, magnetized zones. In addition, the effect of geometric configuration of this inclusion on the plastic region evolution has close relationship of creep damage advancement in experiments

  2. Executive functions in mild cognitive impairment: emergence and breakdown of neural plasticity.

    Science.gov (United States)

    Clément, Francis; Gauthier, Serge; Belleville, Sylvie

    2013-05-01

    Our goal was to test the effect of disease severity on the brain activation associated with two executive processes: manipulation and divided attention. This was achieved by administrating a manipulation task and a divided attention task using functional magnetic resonance imaging to 24 individuals with mild cognitive impairment (MCI) and 14 healthy controls matched for age, sex and education. The Mattis Dementia Rating Scale was used to divide persons with MCI into those with better and worse cognitive performances. Both tasks were associated with more brain activation in the MCI group with higher cognition than in healthy controls, particularly in the left frontal areas. Correlational analyses indicated that greater activation in a frontostriatal network hyperactivated by the higher-cognition group was related with better task performance, suggesting that these activations may support functional reorganization of a compensatory nature. By contrast, the lower-cognition group failed to show greater cerebral hyperactivation than controls during the divided attention task and, during the manipulation task, and showed less brain activation than controls in the left ventrolateral cortex, a region commonly hypoactivated in patients with Alzheimer's disease. These findings indicate that, during the early phase of MCI, executive functioning benefits from neural reorganization, but that a breakdown of this brain plasticity characterizes the late stages of MCI. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Our plastic age

    OpenAIRE

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste pl...

  4. Neural Plastic Effects of Cognitive Training on Aging Brain

    Directory of Open Access Journals (Sweden)

    Natalie T. Y. Leung

    2015-01-01

    Full Text Available Increasing research has evidenced that our brain retains a capacity to change in response to experience until late adulthood. This implies that cognitive training can possibly ameliorate age-associated cognitive decline by inducing training-specific neural plastic changes at both neural and behavioral levels. This longitudinal study examined the behavioral effects of a systematic thirteen-week cognitive training program on attention and working memory of older adults who were at risk of cognitive decline. These older adults were randomly assigned to the Cognitive Training Group (n=109 and the Active Control Group (n=100. Findings clearly indicated that training induced improvement in auditory and visual-spatial attention and working memory. The training effect was specific to the experience provided because no significant difference in verbal and visual-spatial memory between the two groups was observed. This pattern of findings is consistent with the prediction and the principle of experience-dependent neuroplasticity. Findings of our study provided further support to the notion that the neural plastic potential continues until older age. The baseline cognitive status did not correlate with pre- versus posttraining changes to any cognitive variables studied, suggesting that the initial cognitive status may not limit the neuroplastic potential of the brain at an old age.

  5. Neural Plastic Effects of Cognitive Training on Aging Brain.

    Science.gov (United States)

    Leung, Natalie T Y; Tam, Helena M K; Chu, Leung W; Kwok, Timothy C Y; Chan, Felix; Lam, Linda C W; Woo, Jean; Lee, Tatia M C

    2015-01-01

    Increasing research has evidenced that our brain retains a capacity to change in response to experience until late adulthood. This implies that cognitive training can possibly ameliorate age-associated cognitive decline by inducing training-specific neural plastic changes at both neural and behavioral levels. This longitudinal study examined the behavioral effects of a systematic thirteen-week cognitive training program on attention and working memory of older adults who were at risk of cognitive decline. These older adults were randomly assigned to the Cognitive Training Group (n = 109) and the Active Control Group (n = 100). Findings clearly indicated that training induced improvement in auditory and visual-spatial attention and working memory. The training effect was specific to the experience provided because no significant difference in verbal and visual-spatial memory between the two groups was observed. This pattern of findings is consistent with the prediction and the principle of experience-dependent neuroplasticity. Findings of our study provided further support to the notion that the neural plastic potential continues until older age. The baseline cognitive status did not correlate with pre- versus posttraining changes to any cognitive variables studied, suggesting that the initial cognitive status may not limit the neuroplastic potential of the brain at an old age.

  6. Late changes in barium sulfate aspiration: HRCT features

    International Nuclear Information System (INIS)

    Voloudaki, A.; Ergazakis, N.; Gourtsoyiannis, N.

    2003-01-01

    Aspiration of barium sulfate occurs accidentally. Lung reaction is usually mild in the early phase due to inert character of the substance and long-term reactions or late toxicities are not expected. Little if any fibrotic response is speculated. We present a case with barium aspiration, studied by high-resolution computed tomography (HRCT) 1 year after the event, as late pulmonary sequelae studied by CT have not been described yet, to the best of our knowledge. The HRCT revealed thickened interlobular septa, subpleural lines, subpleural cysts, and centrilobular micronodules along with barium particles in a subpleural distribution. Those findings indicated that barium is capable of producing mild though silent clinically fibrosis. (orig.)

  7. A Conservative Formulation for Plasticity

    Science.gov (United States)

    1992-01-01

    concepts that apply to a broad class of macroscopic models: plastic deformation and plastic flow rule. CONSERVATIVE PLASTICITY 469 3a. Plastic Defrrnation...temperature. We illustrate these concepts with a model that has been used to describe high strain-rate plastic flow in metals [11, 31, 32]. In the case...JOURDREN, AND P. VEYSSEYRE. Un Modele ttyperelastique- Plastique Euldrien Applicable aux Grandes Dtformations: Que/ques R~sultats 1-D. preprint, 1991. 2. P

  8. Wood-plastic combination

    International Nuclear Information System (INIS)

    Schaudy, R.

    1978-02-01

    A review on wood-plastic combinations is given including the production (wood and plastic component, radiation hardening, curing), the obtained properties, present applications and prospects for the future of these materials. (author)

  9. Cytokine profiles in tears accompanying the secondary conjunctival responses induced by nasal allergy.

    Science.gov (United States)

    Pelikan, Zdenek

    2014-02-01

    Allergic conjunctivitis (AC) occurs either in a primary form, due to the allergic reaction localized in the conjunctivae or in a secondary form, induced by an allergic reaction initiated primarily in the nasal mucosa. The purpose of this study was to investigate the cytokine profiles in tears associated with the secondary conjunctival response (SCR) types. In 47 AC patients developing 16 immediate (SICR; p tears. The SCRs were associated with significant concentration changes of particular cytokines in tears (p tears during the phosphate-buffered saline controls or negative SCRs. Different cytokine profiles in the tears accompanying the immediate, late and delayed types of SCR, induced by nasal allergy, would indicate involvement of different hypersensitivity mechanisms in the particular SCR types. The low cytokine concentrations in tears recorded during the SCRs may suggest their origin from the nasal mucosa. These results emphasize the diagnostic value of NPTs with allergens combined with monitoring of various ocular features in patients suffering from the secondary form of AC. These results may also have an impact on the therapeutical approach to this clinical entity.

  10. Plastic deformation and contact area of an elastic-plastic contact of ellipsoid bodies after unloading

    NARCIS (Netherlands)

    Jamari, Jamari; Schipper, Dirk J.

    2007-01-01

    This paper presents theoretical and experimental results of the residual or plastic deformation and the plastic contact area of an elastic–plastic contact of ellipsoid bodies after unloading. There are three regime responses of the deformation and contact area: elastic, elastic–plastic and fully

  11. Factors Influencing Short-term Synaptic Plasticity in the Avian Cochlear Nucleus Magnocellularis

    Directory of Open Access Journals (Sweden)

    Jason Tait Sanchez Quinones

    2015-01-01

    Full Text Available Defined as reduced neural responses during high rates of activity, synaptic depression is a form of short-term plasticity important for the temporal filtering of sound. In the avian cochlear nucleus magnocellularis (NM, an auditory brainstem structure, mechanisms regulating short-term synaptic depression include pre-, post-, and extrasynaptic factors. Using varied paired-pulse stimulus intervals, we found that the time course of synaptic depression lasts up to four seconds at late-developing NM synapses. Synaptic depression was largely reliant on exogenous Ca 2+ -dependent probability of presynaptic neurotransmitter release, and to a lesser extent, on the desensitization of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor (AMPA-R. Interestingly, although extrasynaptic glutamate clearance did not play a significant role in regulating synaptic depression, blocking glutamate clearance at early-developing synapses altered synaptic dynamics, changing responses from depression to facilitation. These results suggest a developmental shift in the relative reliance on pre-, post-, and extrasynaptic factors in regulating short-term synaptic plasticity in NM.

  12. The mediation effect of menstrual phase on negative emotion processing: evidence from N2.

    Science.gov (United States)

    Wu, Haiyan; Chen, Chunping; Cheng, Dazhi; Yang, Suyong; Huang, Ruiwang; Cacioppo, Stephanie; Luo, Yue-Jia

    2014-01-01

    Numerous studies have shown a 'negativity bias' in emotion processing and effect of menstrual phase on emotion processing. Most of these results, however, did not match the arousal of different types of stimuli. The present study examined the time course of negative emotion processing across different menstrual phases (e.g., late luteal/premenstrual phase and follicular phase) when the arousal level of negative and neutral stimuli was equal. Following previous studies, an oddball paradigm was utilized in present study. Participants viewed neutral and negative (highly (HN) and moderately negative (MN)) stimuli with matched arousal and were asked to make deviant vs. standard judgments. The behavioral results showed a higher accuracy for HN stimuli than neutral stimuli, and the other comparisons were not significant. The major event-related potential (ERP) finding was that N2 amplitude was larger for MN than neutral in the late luteal phase, whereas such difference was absent during the follicular phase. Moreover, The N2 for HN stimuli was larger in late luteal phase than in follicular phase. Therefore, female may be with higher sensitivity to MN stimuli during late luteal phase than during follicular phase when the arousal of stimuli was well controlled. These results provide additional insight to premenstrual affective syndrome and affective disorder.

  13. A Nonlocal Peridynamic Plasticity Model for the Dynamic Flow and Fracture of Concrete.

    Energy Technology Data Exchange (ETDEWEB)

    Vogler, Tracy; Lammi, Christopher James

    2014-10-01

    A nonlocal, ordinary peridynamic constitutive model is formulated to numerically simulate the pressure-dependent flow and fracture of heterogeneous, quasi-brittle ma- terials, such as concrete. Classical mechanics and traditional computational modeling methods do not accurately model the distributed fracture observed within this family of materials. The peridynamic horizon, or range of influence, provides a characteristic length to the continuum and limits localization of fracture. Scaling laws are derived to relate the parameters of peridynamic constitutive model to the parameters of the classical Drucker-Prager plasticity model. Thermodynamic analysis of associated and non-associated plastic flow is performed. An implicit integration algorithm is formu- lated to calculate the accumulated plastic bond extension and force state. The gov- erning equations are linearized and the simulation of the quasi-static compression of a cylinder is compared to the classical theory. A dissipation-based peridynamic bond failure criteria is implemented to model fracture and the splitting of a concrete cylinder is numerically simulated. Finally, calculation of the impact and spallation of a con- crete structure is performed to assess the suitability of the material and failure models for simulating concrete during dynamic loadings. The peridynamic model is found to accurately simulate the inelastic deformation and fracture behavior of concrete during compression, splitting, and dynamically induced spall. The work expands the types of materials that can be modeled using peridynamics. A multi-scale methodology for simulating concrete to be used in conjunction with the plasticity model is presented. The work was funded by LDRD 158806.

  14. Numerical investigation of the late-time Kerr tails

    Energy Technology Data Exchange (ETDEWEB)

    Racz, Istvan; Toth, Gabor Zs, E-mail: iracz@rmki.kfki.hu, E-mail: tgzs@rmki.kfki.hu [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

    2011-10-07

    The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I{sup +} are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I{sup +}. The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.

  15. Numerical investigation of the late-time Kerr tails

    International Nuclear Information System (INIS)

    Racz, Istvan; Toth, Gabor Zs

    2011-01-01

    The late-time behavior of a scalar field on fixed Kerr background is examined in a numerical framework incorporating the techniques of conformal compactification and hyperbolic initial value formulation. The applied code is 1+(1+2) as it is based on the use of the spectral method in the angular directions while in the time-radial section fourth order finite differencing, along with the method of lines, is applied. The evolution of various types of stationary and non-stationary pure multipole initial states are investigated. The asymptotic decay rates are determined not only in the domain of outer communication but along the event horizon and at future null infinity as well. The decay rates are found to be different for stationary and non-stationary initial data, and they also depend on the fall off properties of the initial data toward future null infinity. The energy and angular momentum transfers are found to show significantly different behavior in the initial phase of the time evolution. The quasinormal ringing phase and the tail phase are also investigated. In the tail phase, the decay exponents for the energy and angular momentum losses at I + are found to be smaller than at the horizon which is in accordance with the behavior of the field itself and it means that at late times the energy and angular momentum falling into the black hole become negligible in comparison with the energy and angular momentum radiated toward I + . The energy and angular momentum balances are used as additional verifications of the reliability of our numerical method.

  16. Learning to sing with the accompaniment of the gusle in Serbia in the XXI century

    Directory of Open Access Journals (Sweden)

    Lajić-Mihajlović Danka

    2012-01-01

    Full Text Available In this paper, learning to sing with the accompaniment of the gusle is reconsidered within the concept of the preservation of traditional folk music as an intangible cultural heritage, that is, as a specific form of music education. Having dealt with a traditional way of providing continuity in the practice of guslars` (i. e. gusle players - which is learning by observing and imitating more experienced family members or guslars from nearby surrounding - some crucial moments in the history of singing with the accompaniment of the gusle, which also influenced the process of transmitting this skill, are demonstrated. In recent times, singing with the accompaniment of the gusle has been mastered not only within family circles but also in associations of guslars, at private schools of music, and lately there has also been an opportunity to learn this skill at some state schools of music. Accordingly, interviews with the members of an Association of guslars association that is particularly distinguished by the fostering young guslars, and interviews with gusle teachers and pupils who attend schools of music were used as primary sources for this paper, together with the specific experience of the author as a president of the jury in a young guslars’ competition. Since the poetic content of the songs is primarily learnt from printed collections or audio recordings, future guslars in fact master the musical skills of playing and singing along the instrument, that is, the skill of the vocal interpretation of a chosen written poetic text. Concerning these, some programmes and methods are discussed, as well as their effects on young guslars’ competence, principally from the point of style and aesthetics. Attention is particularly drawn to flaws in the teaching concept of future gusle players at state schools of music. In conclusion, the necessity of applying ethnomusicological findings to activities concerning the preservation of an intangible cultural

  17. Short-Term Plasticity of the Visuomotor Map during Grasping Movements in Humans

    Science.gov (United States)

    Safstrom, Daniel; Edin, Benoni B.

    2005-01-01

    During visually guided grasping movements, visual information is transformed into motor commands. This transformation is known as the "visuomotor map." To investigate limitations in the short-term plasticity of the visuomotor map in normal humans, we studied the maximum grip aperture (MGA) during the reaching phase while subjects grasped objects…

  18. Synaptic Plasticity and Nociception

    Institute of Scientific and Technical Information of China (English)

    ChenJianguo

    2004-01-01

    Synaptic plasticity is one of the fields that progresses rapidly and has a lot of success in neuroscience. The two major types of synaptie plasticity: long-term potentiation ( LTP and long-term depression (LTD are thought to be the cellular mochanisms of learning and memory. Recently, accumulating evidence suggests that, besides serving as a cellular model for learning and memory, the synaptic plasticity involves in other physiological or pathophysiological processes, such as the perception of pain and the regulation of cardiovascular system. This minireview will focus on the relationship between synaptic plasticity and nociception.

  19. Spectrotemporal dynamics of auditory cortical synaptic receptive field plasticity.

    Science.gov (United States)

    Froemke, Robert C; Martins, Ana Raquel O

    2011-09-01

    The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that collectively determine the suprathreshold tuning curves of cortical neurons. Long-term cortical plasticity also requires co-activation of subcortical neuromodulatory control nuclei such as the cholinergic nucleus basalis, particularly in adults. Regardless of developmental stage, regulation of inhibition seems to be a general mechanism by which changes in sensory experience and neuromodulatory state can remodel cortical receptive fields. We discuss recent findings suggesting that the microdynamics of synaptic receptive field plasticity unfold as a multi-phase set of distinct phenomena, initiated by disrupting the balance between excitation and inhibition, and eventually leading to wide-scale changes to many synapses throughout the cortex. These changes are coordinated to enhance the representations of newly-significant stimuli, possibly for improved signal processing and language learning in humans. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. The effect of martensite plasticity on the cyclic deformation of super-elastic NiTi shape memory alloy

    International Nuclear Information System (INIS)

    Song, Di; Kang, Guozheng; Kan, Qianhua; Yu, Chao; Zhang, Chuanzeng

    2014-01-01

    Based on stress-controlled cyclic tension–unloading experiments with different peak stresses, the effect of martensite plasticity on the cyclic deformation of super-elastic NiTi shape memory alloy micro-tubes is investigated and discussed. The experimental results show that the reverse transformation from the induced martensite phase to the austenite phase is gradually restricted by the plastic deformation of the induced martensite phase caused by an applied peak stress that is sufficiently high (higher than 900 MPa), and the extent of such restriction increases with further increasing the peak stress. The residual and peak strains of super-elastic NiTi shape memory alloy accumulate progressively, i.e., transformation ratchetting occurs during the cyclic tension–unloading with peak stresses from 600 to 900 MPa, and the transformation ratchetting strain increases with the increase of the peak stress. When the peak stress is higher than 900 MPa, the peak strain becomes almost unchanged, but the residual strain accumulates and the dissipation energy per cycle decreases very quickly with the increasing number of cycles due to the restricted reverse transformation by the martensite plasticity. Furthermore, a quantitative relationship between the applied stress and the stabilized residual strain is obtained to reasonably predict the evolution of the peak strain and the residual strain. (paper)

  1. Association of solar flares with coronal mass ejections accompanied by Deca-Hectometric type II radio burst for two solar cycles 23 and 24

    Science.gov (United States)

    Kharayat, Hema; Prasad, Lalan; Pant, Sumit

    2018-05-01

    The aim of present study is to find the association of solar flares with coronal mass ejections (CMEs) accompanied by Deca-Hectometric (DH) type II radio burst for the period 1997-2014 (solar cycle 23 and ascending phase of solar cycle 24). We have used a statistical analysis and found that 10-20∘ latitudinal belt of northern region and 80-90∘ longitudinal belts of western region of the sun are more effective for flare-CME accompanied by DH type II radio burst events. M-class flares (52%) are in good association with the CMEs accompanied by DH type II radio burst. Further, we have calculated the flare position and found that most frequent flare site is at the center of the CME span. However, the occurrence probability of all flares is maximum outside the CME span. X-class flare associated CMEs have maximum speed than that of M, C, and B-class flare associated CMEs. We have also found a good correlation between flare position and central position angle of CMEs accompanied by DH type II radio burst.

  2. Temporal phases of activity-dependent plasticity and memory are mediated by compartmentalized routing of MAPK signaling in aplysia sensory neurons.

    Science.gov (United States)

    Shobe, Justin L; Zhao, Yali; Stough, Shara; Ye, Xiaojing; Hsuan, Vickie; Martin, Kelsey C; Carew, Thomas J

    2009-01-15

    An activity-dependent form of intermediate memory (AD-ITM) for sensitization is induced in Aplysia by a single tail shock that gives rise to plastic changes (AD-ITF) in tail sensory neurons (SNs) via the interaction of action potential firing in the SN coupled with the release of serotonin in the CNS. Activity-dependent long-term facilitation (AD-LTF, lasting >24hr) requires protein synthesis dependent persistent mitogen-activated protein kinase (MAPK) activation and translocation to the SN nucleus. We now show that the induction of the earlier temporal phase (AD-ITM and AD-ITF), which is translation and transcription independent, requires the activation of a compartmentally distinct novel signaling cascade that links second messengers, MAPK and PKC into a unified pathway within tail SNs. Since both AD-ITM and AD-LTM require MAPK activity, these collective findings suggest that presynaptic SNs route the flow of molecular information to distinct subcellular compartments during the induction of activity-dependent long-lasting memories.

  3. Late consequences of ARS survivors of different γβ- and γη-radiation injuries

    International Nuclear Information System (INIS)

    Nadejina, N.M.; Galstian, I.A.; Savitsky, A.A.; Rtischeva, J.N.; Uvacheva, I.V.; Kashirina, O.G.

    2000-01-01

    Purpose: to study of health in the late consequences period the acute radiation syndrome (ARS) survivors of different radiation accidents took place in former USSR since 1953. Method: clinical observation, clinical database. Results: radiation cataract were revealed at the survivors who have undergone relatively uniform γβ-radiation exposure in a doze not less 2.0 Gy. At non-uniform γη-radiation exposure the cataract development was observed at smaller dozes for bone marrow. The local radiation injures of skin were observed at relatively uniform γβ- and at non-uniform γη-radiation exposure. The main factors for working disability are the presence of relapsing late radiation ulcers in the late period of local γβ-injures 2-4 degrees and the presence of amputation stumps at γη-radiation exposure. For oncologic diseases developed in the period of late consequences of ARS the dose dependence is not revealed. Transient different changes of blood parameters are not dose dependent. The repeated (relatively stable) changes, as a rule, are connected to presence of heavy accompanying diseases (chronic hepatitis, myelodysplastic syndrome, family neutropenia). We observed development of chronic myeloleukemia at the ARS survivor. Hospital morbidity of these groups of ARS survivors demonstrates absence of the radiation influence to development of somatic pathology in the period of the late consequences. Conclusion: health of the ARS survivors in the late consequences period is determined by presence of consequences of local radiation injures of skin, radiation cataract and different concurrent somatic diseases. The type of irradiation (γβ- and γη-) in many respects determines the speed of occurrence, expression and some clinical features of the late consequences of local radiation injures. (author)

  4. Food safety involving ingestion of foods and beverages prepared with phthalate-plasticizer-containing clouding agents.

    Science.gov (United States)

    Yen, Tzung-Hai; Lin-Tan, Dan-Tzu; Lin, Ja-Liang

    2011-11-01

    In May 2011, the illegal use of the phthalate plasticizer di(2-ethylhexyl) phthalate in clouding agents for use in foods and beverages was reported in Taiwan. This food scandal has caused shock and panic among the majority of Taiwanese people and has attracted international attention. Phthalate exposure is assessed by ambient monitoring or human biomonitoring. Ambient monitoring relies on measuring chemicals in environmental media, foodstuff and consumer products. Human biomonitoring determines body burden by measuring the chemicals, their metabolites or specific reaction products in human specimens. In mammalian development, the fetus is set to develop into a female. Because the female phenotype is the default, impairment of testosterone production or action before the late phase may lead to feminizing characteristics. Phthalates disrupt the development of androgen-dependent structures by inhibiting fetal testicular testosterone biosynthesis. The spectrum of effects obtained following perinatal exposure of male rats to phthalates has remarkable similarities with the human testicular dysgenesis syndrome. Epidemiological studies have suggested associations between phthalate exposure and shorter gestational age, shorter anogenital distance, shorter penis, incomplete testicular descent, sex hormone alteration, precocious puberty, pubertal gynecomastia, premature thelarche, rhinitis, eczema, asthma, low birth weight, attention deficit hyperactivity disorder, low intelligence quotient, thyroid hormone alteration, and hypospadias in infants and children. Furthermore, many studies have suggested associations between phthalate exposure and increased sperm DNA damage, decreased proportion of sperm with normal morphology, decreased sperm concentration, decreased sperm morphology, sex hormone alteration, decreased pulmonary function, endometriosis, uterine leiomyomas, breast cancer, obesity, hyperprolactinemia, and thyroid hormone alteration in adults. Finally, the number of

  5. Food safety involving ingestion of foods and beverages prepared with phthalate-plasticizer-containing clouding agents

    Directory of Open Access Journals (Sweden)

    Tzung-Hai Yen

    2011-11-01

    Full Text Available In May 2011, the illegal use of the phthalate plasticizer di(2-ethylhexyl phthalate in clouding agents for use in foods and beverages was reported in Taiwan. This food scandal has caused shock and panic among the majority of Taiwanese people and has attracted international attention. Phthalate exposure is assessed by ambient monitoring or human biomonitoring. Ambient monitoring relies on measuring chemicals in environmental media, foodstuff and consumer products. Human biomonitoring determines body burden by measuring the chemicals, their metabolites or specific reaction products in human specimens. In mammalian development, the fetus is set to develop into a female. Because the female phenotype is the default, impairment of testosterone production or action before the late phase may lead to feminizing characteristics. Phthalates disrupt the development of androgen-dependent structures by inhibiting fetal testicular testosterone biosynthesis. The spectrum of effects obtained following perinatal exposure of male rats to phthalates has remarkable similarities with the human testicular dysgenesis syndrome. Epidemiological studies have suggested associations between phthalate exposure and shorter gestational age, shorter anogenital distance, shorter penis, incomplete testicular descent, sex hormone alteration, precocious puberty, pubertal gynecomastia, premature thelarche, rhinitis, eczema, asthma, low birth weight, attention deficit hyperactivity disorder, low intelligence quotient, thyroid hormone alteration, and hypospadias in infants and children. Furthermore, many studies have suggested associations between phthalate exposure and increased sperm DNA damage, decreased proportion of sperm with normal morphology, decreased sperm concentration, decreased sperm morphology, sex hormone alteration, decreased pulmonary function, endometriosis, uterine leiomyomas, breast cancer, obesity, hyperprolactinemia, and thyroid hormone alteration in adults

  6. Processes accompanying of mantle plume emplacement into continental lithosphere: Evidence from NW Arabian plate, Western Syria

    Science.gov (United States)

    Sharkov, E. V.

    2015-12-01

    Lower crustal xenoliths occurred in the Middle Cretaceous lamprophyre diatremes in Jabel Ansaria (Western Syria) (Sharkov et al., 1992). They are represented mainly garnet granulites and eclogite-like rocks, which underwent by deformations and retrograde metamorphism, and younger fresh pegmatoid garnet-kaersutite-clinopyroxene (Al-Ti augite) rocks; mantle peridotites are absent in these populations. According to mineralogical geothermobarometers, forming of garnet-granulite suite rocks occurred under pressure 13.5-15.4 kbar (depths 45-54 kn) and temperature 965-1115oC. At the same time, among populations of mantle xenoliths in the Late Cenozoic platobasalts of the region, quite the contrary, lower crustal xenoliths are absent, however, predominated spinel lherzolites (fragments of upper cooled rim of a plume head), derived from the close depths (30-40 km: Sharkov, Bogatikov, 2015). From this follows that ancient continental crust was existed here even in the Middle Cretaceous, but in the Late Cenozoic was removed by extended mantle plume head; at that upper sialic crust was not involved in geomechanic processes, because Precambrian metamorphic rocks survived as a basement for Cambrian to Cenozoic sedimentary cover of Arabian platform. In other words, though cardinal rebuilding of deep-seated structure of the region occurred in the Late Cenozoic but it did not affect on the upper shell of the ancient lithosphere. Because composition of mantle xenolithis in basalts is practically similar worldwide, we suggest that deep-seated processes are analogous also. As emplacement of the mantle plume heads accompanied by powerful basaltic magmatism, very likely that range of lower (mafic) continental crust existence is very convenient for extension of plume heads and their adiabatic melting. If such level, because of whatever reasons, was not reached, melting was limited but appeared excess of volatile matters which led to forming of lamprophyre or even kimberlite.

  7. Synthesis of biodegradable plastic from tapioca with N-Isopropylacrylamid and chitosan using glycerol as plasticizer

    Science.gov (United States)

    Syaubari; Safwani, S.; Riza, M.

    2018-04-01

    One of natural polymers that can be used as raw material in the manufacture of biodegradable plastic is tapioca and chitosan. The addition of other compounds such as glycerol as plasticizer is to improve the characteristics of the plastic that already produced. N- Isopropylacrylamid (NIPAm) is an organic compound that can be synthesized into a polymer or polymer grafting which also biodegradable too. This research aims tostudy the synthesis of biodegradable plastics from tapioca with the addition of chitosan, NIPAm, poly(NIPAm) and analyze the characteristics of biodegradable plastics that already produced. This research was done in three stages, there are (1) polymerization NIPAm, (2) the grafting of chitosan-poly NIPAm and (3) the synthesis of biodegradable plastics from starch mixture with variation of addition chitosan, NIPAm, poly(NIPAm), chitosan-graft-poly(NIPAm) and also variations of glycerol as plasticizer. The results of this research is a thin sheet of plastic which is will get analyzed for the characteristics of functional groups, mechanical, morphological and its biodegradability. FTIR spectra showed the grafting process with the new group formation of CO single-bond at 850 cm-1. Plastic with the addition of NIPAm and 1 ml glycerol has the highest tensile strength value about 31.1 MPa. Plastic with poly(NIPAm) and 4 ml glycerol produces the highest elongation value about 153.72%. Plastic with Chitosan-graft-poly(NIPAm) with 1 ml glycerol has the longest biodegradation because of the small mass-loss for six weeks which is about 6.6%.

  8. New perspectives in plastic biodegradation.

    Science.gov (United States)

    Sivan, Alex

    2011-06-01

    During the past 50 years new plastic materials, in various applications, have gradually replaced the traditional metal, wood, leather materials. Ironically, the most preferred property of plastics--durability--exerts also the major environmental threat. Recycling has practically failed to provide a safe solution for disposal of plastic waste (only 5% out of 1 trillion plastic bags, annually produced in the US alone, are being recycled). Since the most utilized plastic is polyethylene (PE; ca. 140 million tons/year), any reduction in the accumulation of PE waste alone would have a major impact on the overall reduction of the plastic waste in the environment. Since PE is considered to be practically inert, efforts were made to isolate unique microorganisms capable of utilizing synthetic polymers. Recent data showed that biodegradation of plastic waste with selected microbial strains became a viable solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Wakefulness delta waves increase after cortical plasticity induction.

    Science.gov (United States)

    Assenza, G; Pellegrino, G; Tombini, M; Di Pino, G; Di Lazzaro, V

    2015-06-01

    Delta waves (DW) are present both during sleep and in wakefulness. In the first case, DW are considered effectors of synaptic plasticity, while in wakefulness, when they appear in the case of brain lesions, their functional meaning is not unanimously recognized. To throw light on the latter, we aimed to investigate the impact on DW exerted by the cortical plasticity-inducing protocol of intermittent theta burst stimulation (iTBS). Twenty healthy subjects underwent iTBS (11 real iTBS and nine sham iTBS) on the left primary motor cortex with the aim of inducing long-term potentiation (LTP)-like phenomena. Five-minute resting open-eye 32-channel EEG, right opponens pollicis motor-evoked potentials (MEPs), and alertness behavioral scales were collected before and up to 30 min after the iTBS. Power spectral density (PSD), interhemispheric coherence between homologous sensorimotor regions, and intrahemispheric coherence were calculated for the frequency bands ranging from delta to beta. Real iTBS induced a significant increase of both MEP amplitude and DW PSD lasting up to 30 min after stimulation, while sham iTBS did not. The DW increase was evident over frontal areas ipsilateral and close to the stimulated cortex (electrode F3). Neither real nor sham iTBS induced significant modifications in the PSD of theta, alpha, and beta bands and in the interhemispheric coherence. Behavioral visuo-analogic scales score did not demonstrate changes in alertness after stimulations. No correlations were found between MEP amplitude and PSD changes in the delta band. Our data showed that LTP induction in the motor cortex during wakefulness, by means of iTBS, is accompanied by a large and enduring increase of DW over the ipsilateral frontal cortex. The present results are strongly in favor of a prominent role of DW in the neural plasticity processes taking place during the awake state. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland

  10. Avalanches and plastic flow in crystal plasticity: an overview

    Science.gov (United States)

    Papanikolaou, Stefanos; Cui, Yinan; Ghoniem, Nasr

    2018-01-01

    Crystal plasticity is mediated through dislocations, which form knotted configurations in a complex energy landscape. Once they disentangle and move, they may also be impeded by permanent obstacles with finite energy barriers or frustrating long-range interactions. The outcome of such complexity is the emergence of dislocation avalanches as the basic mechanism of plastic flow in solids at the nanoscale. While the deformation behavior of bulk materials appears smooth, a predictive model should clearly be based upon the character of these dislocation avalanches and their associated strain bursts. We provide here a comprehensive overview of experimental observations, theoretical models and computational approaches that have been developed to unravel the multiple aspects of dislocation avalanche physics and the phenomena leading to strain bursts in crystal plasticity.

  11. Roles of the plasticity regions of Helicobacter pylori in gastroduodenal pathogenesis.

    Science.gov (United States)

    Yamaoka, Yoshio

    2008-05-01

    Putative virulence genes of Helicobacter pylori are generally classified into three categories: strain-specific genes, phase-variable genes and genes with variable structures/genotypes. Among these, there has recently been considerable interest in strain-specific genes found outside of the cag pathogenicity island, especially genes in the plasticity regions. Nearly half of the strain-specific genes of H. pylori are located in the plasticity regions in strains 26695 and J99. Strain HPAG1, however, seems to lack a typical plasticity region; instead it has 43 HPAG1-specific genes which are either undetectable or incompletely represented in the genomes of strains 26695 and J99. Recent studies showed that certain genes or combination of genes in this region may play important roles in the pathogenesis of H. pylori-associated gastroduodenal diseases. Most previous studies have focused on the plasticity region in strain J99 (jhp0914-jhp0961) and the jhp0947 gene and the duodenal ulcer promoting (dupA) gene are good candidate markers for gastroduodenal diseases although there are some paradoxical findings. The jhp0947 gene is reported to be associated with an increased risk of both duodenal ulcers and gastric cancers, whereas the dupA gene, which encompasses jhp0917 and jhp0918, is reported to be associated with an increased risk of duodenal ulcers and protection against gastric cancers. In addition, recent studies showed that approximately 10-30 % of clinical isolates possess a 16.3 kb type IV secretion apparatus (tfs3) in the plasticity region. Studies on the plasticity region have only just begun, and further investigation is necessary to elucidate the roles of genes in this region in gastroduodenal pathogenesis.

  12. Melting the Plastic Ceiling: Overcoming Obstacles to Foster Leadership in Women Plastic Surgeons.

    Science.gov (United States)

    Silva, Amanda K; Preminger, Aviva; Slezak, Sheri; Phillips, Linda G; Johnson, Debra J

    2016-09-01

    The underrepresentation of women leaders in plastic surgery echoes a phenomenon throughout society. The importance of female leadership is presented, and barriers to gender equality in plastic surgery, both intrinsic and extrinsic, are discussed. Strategies for fostering women in leadership on an individual level and for the specialty of plastic surgery are presented.

  13. [Infected knee prostheses. Part 2: chronic late infections].

    Science.gov (United States)

    Herrmann, P; Thoele, P; Heppert, V

    2013-06-01

    Treatment of late and chronic infections, which require the replacement of all the infected implant material. All infections lasting more than 4 weeks that have been proven to be bacterial and/or obvious signs of infection. Unsuitable for anesthesia, high acute infection with sepsis and risk for bacteremia with danger to life, large soft tissue damage where plastic surgery coverage is not possible. Arthrotomy, synovectomy, removal of all foreign bodies including all residue of polymethylmethacrylate (PMMA), jet lavage, spacer, drainage, wound closure or temporary closure using vacuum sealing. Bed rest with a leg brace and drainage until daily drainage volume is exchange of the spacer. In the literature, the success rate for both the one-stage or the two-stage procedure is about 80-95%. In our very nonhomogeneous collective the overall rate of success is about 81%.

  14. Small-scale dislocation plasticity in strontium titanate

    Energy Technology Data Exchange (ETDEWEB)

    Stukowski, Alexander; Javaid, Farhan; Durst, Karsten; Albe, Karsten [Technische Universitaet Darmstadt (Germany)

    2016-07-01

    Strontium titanate (STO) is an optically transparent perovskite oxide ceramic material. In contrast to other ceramics, single crystal STO plastically deforms under ambient condition, without showing a phase transition or early fracture. This remarkable ductility makes it a prime candidate for different technological applications. However, while the mechanical behavior of bulk STO has been studied extensively using uniaxial compression testing techniques, little is known about the local, small-scale behavior and the details of dislocation-based nanoplasticity in this perovskite material. In this contribution we compare results obtained from new nanoindentation experiments and corresponding large-scale molecular dynamics simulations. The evolution of the plastic zone and dislocation structures that form underneath the indenter is investigated using etch-pit methods in experiments and a novel three-dimensional defect identification technique in atomistic computer models. The latter allows tracing the evolution of the complete dislocation line network as function of indentation depth, quantifying the activity of different slip systems, and correlating this information with the recorded load-displacement curves and hardness data.

  15. Different rates of DNA replication at early versus late S-phase sections: multiscale modeling of stochastic events related to DNA content/EdU (5-ethynyl-2'deoxyuridine) incorporation distributions.

    Science.gov (United States)

    Li, Biao; Zhao, Hong; Rybak, Paulina; Dobrucki, Jurek W; Darzynkiewicz, Zbigniew; Kimmel, Marek

    2014-09-01

    Mathematical modeling allows relating molecular events to single-cell characteristics assessed by multiparameter cytometry. In the present study we labeled newly synthesized DNA in A549 human lung carcinoma cells with 15-120 min pulses of EdU. All DNA was stained with DAPI and cellular fluorescence was measured by laser scanning cytometry. The frequency of cells in the ascending (left) side of the "horseshoe"-shaped EdU/DAPI bivariate distributions reports the rate of DNA replication at the time of entrance to S phase while their frequency in the descending (right) side is a marker of DNA replication rate at the time of transition from S to G2 phase. To understand the connection between molecular-scale events and scatterplot asymmetry, we developed a multiscale stochastic model, which simulates DNA replication and cell cycle progression of individual cells and produces in silico EdU/DAPI scatterplots. For each S-phase cell the time points at which replication origins are fired are modeled by a non-homogeneous Poisson Process (NHPP). Shifted gamma distributions are assumed for durations of cell cycle phases (G1, S and G2 M), Depending on the rate of DNA synthesis being an increasing or decreasing function, simulated EdU/DAPI bivariate graphs show predominance of cells in left (early-S) or right (late-S) side of the horseshoe distribution. Assuming NHPP rate estimated from independent experiments, simulated EdU/DAPI graphs are nearly indistinguishable from those experimentally observed. This finding proves consistency between the S-phase DNA-replication rate based on molecular-scale analyses, and cell population kinetics ascertained from EdU/DAPI scatterplots and demonstrates that DNA replication rate at entrance to S is relatively slow compared with its rather abrupt termination during S to G2 transition. Our approach opens a possibility of similar modeling to study the effect of anticancer drugs on DNA replication/cell cycle progression and also to quantify other

  16. The anti-inflammatory effect of topical tofacitinib on immediate and late-phase cutaneous allergic reactions in dogs: a placebo-controlled pilot study.

    Science.gov (United States)

    Blubaugh, Amanda; Rissi, Daniel; Elder, Deborah; Denley, Tara; Eguiluz-Hernandez, Sitka; Banovic, Frane

    2018-03-06

    Topical Janus kinase (JAK) inhibition is a promising therapeutic target for several inflammatory skin diseases of humans. To evaluate the anti-inflammatory effect of tofacitinib, a JAK 1/3 inhibitor, on immediate and late-phase skin reactions in dogs. Five healthy laboratory beagle dogs. Topical tofacitinib (total daily dosage: 0.5 mg/cm 2 ) or its gel vehicle were applied on either the left or right lateral thorax of each dog for eight days. Three days before application and after eight days of topical treatment, intradermal injections of histamine and anticanine-IgE antibodies were performed on both sides; they were evaluated by an investigator blinded to the interventions. The tofacitinib gel was well-tolerated; one dog developed mild erythema at Day 5 that resolved by the next application. Treatment with tofacitinib reduced histamine and anticanine-IgE global wheal scores (one-way ANOVA, P ≤ 0.005 for both) compared to baseline; there was no significant difference for the vehicle placebo (histamine; P = 0.163; IgE, P = 0.223). Late-phase reactions (LPRs) were markedly, but not significantly reduced after tofacitinib treatment (P = 0.071). A blinded histological evaluation of 6 h-anti-IgE-associated LPRs revealed a significant reduction in the total leucocyte superficial dermal cellularity (P = 0.022), as well as eosinophil (P = 0.022) and mast cell (P = 0.022) counts at tofacitinib-treated sides compared with pretreatment values. Post-treatment complete blood counts and serum chemistry profiles did not show relevant tofacitinib-induced changes. Our observations suggest that topical tofacitinib exerts an inhibitory effect on activated canine skin-emigrating immune cells; this drug should be investigated further as a topical immunosuppressive drug in dogs. © 2018 ESVD and ACVD.

  17. Cardioprotective effects of early and late aerobic exercise training in experimental pulmonary arterial hypertension.

    Science.gov (United States)

    Moreira-Gonçalves, Daniel; Ferreira, Rita; Fonseca, Hélder; Padrão, Ana Isabel; Moreno, Nuno; Silva, Ana Filipa; Vasques-Nóvoa, Francisco; Gonçalves, Nádia; Vieira, Sara; Santos, Mário; Amado, Francisco; Duarte, José Alberto; Leite-Moreira, Adelino F; Henriques-Coelho, Tiago

    2015-11-01

    Clinical studies suggest that aerobic exercise can exert beneficial effects in pulmonary arterial hypertension (PAH), but the underlying mechanisms are largely unknown. We compared the impact of early or late aerobic exercise training on right ventricular function, remodeling and survival in experimental PAH. Male Wistar rats were submitted to normal cage activity (SED), exercise training in early (EarlyEX) and in late stage (LateEX) of PAH induced by monocrotaline (MCT, 60 mg/kg). Both exercise interventions resulted in improved cardiac function despite persistent right pressure-overload, increased exercise tolerance and survival, with greater benefits in EarlyEX+MCT. This was accompanied by improvements in the markers of cardiac remodeling (SERCA2a), neurohumoral activation (lower endothelin-1, brain natriuretic peptide and preserved vascular endothelial growth factor mRNA), metabolism and mitochondrial oxidative stress in both exercise interventions. EarlyEX+MCT provided additional improvements in fibrosis, tumor necrosis factor-alpha/interleukin-10 and brain natriuretic peptide mRNA, and beta/alpha myosin heavy chain protein expression. The present study demonstrates important cardioprotective effects of aerobic exercise in experimental PAH, with greater benefits obtained when exercise training is initiated at an early stage of the disease.

  18. Some Limitations in the Use of Plastic and Dyed Plastic Dosimeters

    DEFF Research Database (Denmark)

    Miller, Arne; Bjergbakke, Erling; McLaughlin, W. L.

    1975-01-01

    Several practical plastic and dyed plastic dosimeters were examined under irradiation conditions similar to those used for radiation processing of materials. Cellulose triacetate, polymethyl methacrylate, polyvinyl chloride, dyed polymethyl methacrylate, dyed Cellophane and dyed Nylon were given...

  19. In-Vial Micro-Matrix-Solid Phase Dispersion for the Analysis of Fragrance Allergens, Preservatives, Plasticizers, and Musks in Cosmetics

    Directory of Open Access Journals (Sweden)

    Maria Celeiro

    2014-07-01

    Full Text Available Fragrance allergens, preservatives, plasticizers, and synthetic musks are usually present in cosmetic and personal care products formulations and many of them are subjected to use restrictions or labeling requirements. Matrix solid-phase dispersion (MSPD is a very suitable analytical technique for the extraction of these compounds providing a simple, low cost sample preparation, and the possibility of performing both extraction and clean-up in one step, reducing possible contamination and analyte losses. This extraction technique has been successfully applied to many cosmetics ingredients allowing obtaining quantitative recoveries. A new very simple micro-MSPD procedure performing the disruption step in a vial is proposed for the gas chromatography-mass spectrometry (GC-MS analysis of 66 chemicals usually present in cosmetics and personal care products. The method was validated showing general recoveries between 80% and 110%, relative standard deviation (RSD values lower than 15%, and limits of detection (LODs below 30 ng·g−1. The validated method was applied to a broad range of cosmetics and personal care products, including several products intended for baby care.

  20. A model for plasticity kinetics and its role in simulating the dynamic behavior of Fe at high strain rates

    Energy Technology Data Exchange (ETDEWEB)

    Colvin, J D; Minich, R W; Kalantar, D H

    2007-03-29

    The recent diagnostic capability of the Omega laser to study solid-solid phase transitions at pressures greater than 10 GPa and at strain rates exceeding 10{sup 7} s{sup -1} has also provided valuable information on the dynamic elastic-plastic behavior of materials. We have found, for example, that plasticity kinetics modifies the effective loading and thermodynamic paths of the material. In this paper we derive a kinetics equation for the time-dependent plastic response of the material to dynamic loading, and describe the model's implementation in a radiation-hydrodynamics computer code. This model for plasticity kinetics incorporates the Gilman model for dislocation multiplication and saturation. We discuss the application of this model to the simulation of experimental velocity interferometry data for experiments on Omega in which Fe was shock compressed to pressures beyond the {alpha}-to-{var_epsilon} phase transition pressure. The kinetics model is shown to fit the data reasonably well in this high strain rate regime and further allows quantification of the relative contributions of dislocation multiplication and drag. The sensitivity of the observed signatures to the kinetics model parameters is presented.

  1. Metastatic Basal Cell Carcinoma Accompanying Gorlin Syndrome

    Directory of Open Access Journals (Sweden)

    Yeliz Bilir

    2014-01-01

    Full Text Available Gorlin-Goltz syndrome or basal cell nevus syndrome is an autosomal dominant syndrome characterized by skeletal anomalies, numerous cysts observed in the jaw, and multiple basal cell carcinoma of the skin, which may be accompanied by falx cerebri calcification. Basal cell carcinoma is the most commonly skin tumor with slow clinical course and low metastatic potential. Its concomitance with Gorlin syndrome, resulting from a mutation in a tumor suppressor gene, may substantially change morbidity and mortality. A 66-year-old male patient with a history of recurrent basal cell carcinoma was presented with exophthalmus in the left eye and the lesions localized in the left lateral orbita and left zygomatic area. His physical examination revealed hearing loss, gapped teeth, highly arched palate, and frontal prominence. Left orbital mass, cystic masses at frontal and ethmoidal sinuses, and multiple pulmonary nodules were detected at CT scans. Basal cell carcinoma was diagnosed from biopsy of ethmoid sinus. Based on the clinical and typical radiological characteristics (falx cerebri calcification, bifid costa, and odontogenic cysts, the patient was diagnosed with metastatic skin basal cell carcinoma accompanied by Gorlin syndrome. Our case is a basal cell carcinoma with aggressive course accompanying a rarely seen syndrome.

  2. Design for the second phase Rokkasho LLW burial facility

    International Nuclear Information System (INIS)

    Kumata, Tadamasa

    1997-01-01

    Rokkasho Low Level radioactive Waste management center of Japan Nuclear Fuel Limited (hereafter called JNFL) has been operating for five years and about 90,000 (200 liter) drums have already been buried. Currently, JNFL is planning the 2nd phase of the burial program. The basic design of the new facility has been completed and applied for license additionally. Wastes buried in the 2nd phase facility are mainly dry active wastes from nuclear power plants. Inflammable wastes except for plastics are incinerated before they are disposed, because organic materials can generate gas and their degraded materials affect the distribution coefficients of the radionuclides. Most of the aluminum wastes which can generate hydrogen gas by corrosion are also removed from the waste. The 2nd phase facility accepts metal, plastics and non-flammable wastes. These are solidified with mortar in the 200 liter drums at the power plants. The radioactive inventory of the 2nd phase facility is considered to be as much as that of the 1st phase facility. (author)

  3. Synaptic plasticity in the hippocampal area CA1-subiculum projection: implications for theories of memory.

    Science.gov (United States)

    O'Mara, S M; Commins, S; Anderson, M

    2000-01-01

    This paper reviews investigations of synaptic plasticity in the major, and underexplored, pathway from hippocampal area CA1 to the subiculum. This brain area is the major synaptic relay for the majority of hippocampal area CA1 neurons, making the subiculum the last relay of the hippocampal formation prior to the cortex. The subiculum thus has a very major role in mediating hippocampal-cortical interactions. We demonstrate that the projection from hippocampal area CA1 to the subiculum sustains plasticity on a number of levels. We show that this pathway is capable of undergoing both long-term potentiation (LTP) and paired-pulse facilitation (PPF, a short-term plastic effect). Although we failed to induce long-term depression (LTD) of this pathway with low-frequency stimulation (LFS) and two-pulse stimulation (TPS), both protocols can induce a "late-developing" potentiation of synaptic transmission. We further demonstrate that baseline synaptic transmission can be dissociated from paired-pulse stimulation of the same pathway; we also show that it is possible, using appropriate protocols, to change PPF to paired-pulse depression, thus revealing subtle and previously undescribed mechanisms which regulate short-term synaptic plasticity. Finally, we successfully recorded from individual subicular units in the freely-moving animal, and provide a description of the characteristics of such neurons in a pellet-chasing task. We discuss the implications of these findings in relation to theories of the biological consolidation of memory.

  4. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  5. Plasticity resembling spike-timing dependent synaptic plasticity: the evidence in human cortex

    Directory of Open Access Journals (Sweden)

    Florian Müller-Dahlhaus

    2010-07-01

    Full Text Available Spike-timing dependent plasticity (STDP has been studied extensively in a variety of animal models during the past decade but whether it can be studied at the systems level of the human cortex has been a matter of debate. Only recently newly developed non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS have made it possible to induce and assess timing dependent plasticity in conscious human subjects. This review will present a critical synopsis of these experiments, which suggest that several of the principal characteristics and molecular mechanisms of TMS-induced plasticity correspond to those of STDP as studied at a cellular level. TMS combined with a second phasic stimulation modality can induce bidirectional long-lasting changes in the excitability of the stimulated cortex, whose polarity depends on the order of the associated stimulus-evoked events within a critical time window of tens of milliseconds. Pharmacological evidence suggests an NMDA receptor mediated form of synaptic plasticity. Studies in human motor cortex demonstrated that motor learning significantly modulates TMS-induced timing dependent plasticity, and, conversely, may be modulated bidirectionally by prior TMS-induced plasticity, providing circumstantial evidence that long-term potentiation-like mechanisms may be involved in motor learning. In summary, convergent evidence is being accumulated for the contention that it is now possible to induce STDP-like changes in the intact human central nervous system by means of TMS to study and interfere with synaptic plasticity in neural circuits in the context of behaviour such as learning and memory.

  6. A systematic methodology review of phase I radiation dose escalation trials

    International Nuclear Information System (INIS)

    Pijls-Johannesma, Madelon; Mastrigt, Ghislaine van; Hahn, Steve M.; De Ruysscher, Dirk; Baumert, Brigitta G.; Lammering, Guido; Buijsen, Jeroen; Bentzen, Soren M.; Lievens, Yolande; Kramar, Andrew; Lambin, Philippe

    2010-01-01

    Background and purpose: The purpose of this review is to evaluate the methodology used in published phase I radiotherapy (RT) dose escalation trials. A specific emphasis was placed on the frequency of reporting late complications as endpoint. Materials and methods: We performed a systematic literature review using a predefined search strategy to identify all phase I trials reporting on external radiotherapy dose escalation in cancer patients. Results: Fifty-three trials (phase I: n = 36, phase I-II: n = 17) fulfilled the inclusion criteria. Of these, 20 used a modified Fibonacci design for the RT dose escalation, but 32 did not specify a design. Late toxicity was variously defined as >3 months (n = 43) or > 6 months (n = 3) after RT, or not defined (n = 7). In only nine studies the maximum tolerated dose (MTD) was related to late toxicity, while only half the studies reported the minimum follow-up period for dose escalation (n = 26). Conclusion: In phase I RT trials, late complications are often not taken into account and there is currently no consensus on the methodology used for radiation dose escalation studies. We therefore propose a decision-tree algorithm which depends on the endpoint selected and whether a validated early surrogate endpoint is available, in order to choose the most appropriate study design.

  7. 7 CFR 319.37-12 - Prohibited articles accompanying restricted articles.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Prohibited articles accompanying restricted articles... Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products 1,2 § 319.37-12 Prohibited articles accompanying restricted articles. A restricted article for importation into the United States shall not be...

  8. Plastic and Non-plastic Debris Ingestion in Three Gull Species Feeding in an Urban Landfill Environment.

    Science.gov (United States)

    Seif, S; Provencher, J F; Avery-Gomm, S; Daoust, P-Y; Mallory, M L; Smith, P A

    2018-04-01

    Plastic debris is recognized as a widespread, common and problematic environmental pollutant. An important consequence of this pollution is the ingestion of plastic debris by wildlife. Assessing the degree to which different species ingest plastics, and the potential effects of these plastics on their health are important research needs for understanding the impacts of plastic pollution. We examined debris (plastic and other types) ingestion in three sympatric overwintering gull species (Herring gulls Larus smithsonianus, Great Black-backed Gulls Larus marinus, and Iceland Gulls Larus glaucoides) to understand how debris ingestion differs among species, age classes and sexes in gulls. We also assessed how plastic burdens were associated with body condition to investigate how gulls may be affected by debris ingestion. There were no differences among the species, age classes or sexes in the incidence of debris ingestion (plastic or otherwise), the mass or number of debris pieces ingested. We found no correlation between ingested plastics burdens and individual condition. Gulls ingested plastic debris, but also showed high levels of other debris types as well, including metal, glass and building materials, including a metal piece of debris found within an abscess in the stomach. Thus, when the health effects of debris ingestion on gulls, and other species that ingest debris, is of interest, either from a physical or chemical perspective, it may be necessary to consider all debris types and not just plastic burdens as is often currently done for seabirds.

  9. PIKfyve mediates the motility of late endosomes and lysosomes in neuronal dendrites.

    Science.gov (United States)

    Tsuruta, Fuminori; Dolmetsch, Ricardo E

    2015-09-25

    The endosome/lysosome system in the nervous system is critically important for a variety of neuronal functions such as neurite outgrowth, retrograde transport, and synaptic plasticity. In neurons, the endosome/lysosome system is crucial for the activity-dependent internalization of membrane proteins and contributes to the regulation of lipid level on the plasma membrane. Although homeostasis of membrane dynamics plays important roles in the properties of central nervous systems, it has not been elucidated how endosome/lysosome system is regulated. Here, we report that phosphatidylinositol 3-phosphate 5-kinase (PIKfyve) mediates the motility of late endosomes and lysosomes in neuronal dendrites. Endosomes and lysosomes are highly motile in resting neurons, however knockdown of PIKfyve led to a significant reduction in late endosomes and lysosomes motility. We also found that vesicle acidification is crucial for their motility and PIKfyve is associated with this process indirectly. These data suggest that PIKfyve mediates vesicle motility through the regulation of vesicle integrity in neurons. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Education on the Business of Plastic Surgery During Training: A Survey of Plastic Surgery Residents.

    Science.gov (United States)

    Ovadia, Steven A; Gishen, Kriya; Desai, Urmen; Garcia, Alejandro M; Thaller, Seth R

    2018-06-01

    Entrepreneurial skills are important for physicians, especially plastic surgeons. Nevertheless, these skills are not typically emphasized during residency training. Evaluate the extent of business training at plastic surgery residency programs as well as means of enhancing business training. A 6-question online survey was sent to plastic surgery program directors for distribution to plastic surgery residents. Responses from residents at the PGY2 level and above were included for analysis. Tables were prepared to present survey results. Hundred and sixty-six residents including 147 PGY2 and above residents responded to our survey. Only 43.5% reported inclusion of business training in their plastic surgery residency. A majority of residents reported they do not expect on graduation to be prepared for the business aspects of plastic surgery. Additionally, a majority of residents feel establishment of a formal lecture series on the business of plastic surgery would be beneficial. Results from our survey indicate limited training at plastic surgery programs in necessary business skills. Plastic surgery residency programs should consider incorporating or enhancing elements of business training in their curriculum. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  11. Lab-scale thermal analysis of electronic waste plastics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wu-Jun; Tian, Ke; Jiang, Hong, E-mail: jhong@ustc.edu.cn; Yu, Han-Qing

    2016-06-05

    Highlights: • We provided the experimental evidence that WEEE can be recovered by pyrolysis method. • We explored the thermochemical behaviors of WEEE using online TG–FTIR–MS technology. • The intramolecular oxygen atoms play a pivotal role in the formation of PBDD/Fs. - Abstract: In this work, we experimentally revealed the thermochemical decomposition pathway of Decabromodiphenyl ethane (DBDPE) and tetrabromobisphenol A (TBBPA) containing electronic waste plastics using an online thermogravimetric–fourier transform infrared–mass spectroscopy (TG–FTIR–MS) system, a high resolution gas chromatography/high resolution mass (HRGC–MS) spectroscopy, and a fixed-bed reactor. We found the distribution and species of produced bromides can be easily controlled by adjusting pyrolytic temperature, which is particularly crucial to their recycle. From the analysis of the liquid and solid phase obtained from the fixed-bed reactor, we proposed that the ·Br radicals formed during the pyrolysis process may be captured by organic species derived from the depolymerization of plastics to form brominated compounds or by the inorganic species in the plastics, and that these species remained in the char residue after pyrolysis. Our work for the first time demonstrates intramolecular oxygen atoms play a pivotal role in the formation of PBDD/Fs that pyrolysis of oxygen-free BFRs is PBDD/Fs-free, whereas pyrolysis of oxygen-containing BFRs is PBDD/Fs-reduced.

  12. Stratigraphy, landsnail faunas, and paleoenvironmental history of Late Holocene coastal dunes, Tauroa Peninsula, northern New Zealand

    International Nuclear Information System (INIS)

    Brook, F.J.

    1999-01-01

    The post -700 years BP depositional history of the Holocene coastal dunebelt on northwestern Tauroa Peninsula involved an initial progradational phase, then a subsequent predominantly stable phase that began some time after 650 years BP, followed by a highly unstable phase from late prehistoric time to the present-day. Fossil landsnail faunas indicate that sandfield and prostrate shrubland have been the main vegetation types on the dunefield since at least 700 years BP, but that taller shrubland established locally during the later part of the prehistoric period of dunefield stability. Five species of landsnails became extinct on the dunefield in late prehistoric-historic time, probably as a result of vegetation disturbance caused by widespread dune mobilisation and erosion. (author). 19 refs., 3 figs., 1 tab

  13. Precipitation change and its effects on prehistorical human activities in the Gonghe Basin, Northeastern Qinghai-Tibet Plateau during middle and late Holocene

    Science.gov (United States)

    Hou, Xiaoqing; Hou, Guangliang; Wang, Fangfang; Wang, Qingbo

    2018-02-01

    Northeastern Qinghai-tibet Plateau is considered as the ideal region for study of the climate change during the Holocene. Based on the meteorological data, the surface & fossil pollen data, this paper reconstructed the precipitation series of the region since middle Holocene with the GIS and MAT techniques, and discussed its relationship with prehistorical human activities. The results indicate that there are four major climatic phases: (I) Middle Holocene Humid Phase (6300-5000 aBP), with the primitive millet-farming first imported into the region; (II) Late Middle Holocene Sub-humid Phase (5000-3900 aBP), with the millet-farming spread rapidly within the region; (III) Late Holocene Fluctuation Phase (3900-2900 aBP), with the mean annual precipitation dropped down to lower than 240 mm, and a production mode-shift to a combination of cropping and husbandry; (IV) Late Holocene Stationary Phase (2900-0 aBP), with a precipitation alike the modern time, and a steady farming-pastoral economic pattern.

  14. The effects of plastic waves on the numerical convergence of the viscous-plastic and elastic-viscous-plastic sea-ice models

    Science.gov (United States)

    Williams, James; Tremblay, L. Bruno; Lemieux, Jean-François

    2017-07-01

    The plastic wave speed is derived from the linearized 1-D version of the widely used viscous-plastic (VP) and elastic-viscous-plastic (EVP) sea-ice models. Courant-Friedrichs-Lewy (CFL) conditions are derived using the propagation speed of the wave. 1-D numerical experiments of the VP, EVP and EVP* models successfully recreate a reference solution when the CFL conditions are satisfied, in agreement with the theory presented. The IMplicit-EXplicit (IMEX) method is shown to effectively alleviate the plastic wave CFL constraint on the timestep in the implicitly solved VP model in both 1-D and 2-D. In 2-D, the EVP and EVP* models show first order error in the simulated velocity field when the plastic wave is not resolved. EVP simulations are performed with various advective timestep, number of subcycles, and elastic-wave damping timescales. It is found that increasing the number of subcycles beyond that needed to resolve the elastic wave does not improve the quality of the solution. It is found that reducing the elastic wave damping timescale reduces the spatial extent of first order errors cause by the unresolved plastic wave. Reducing the advective timestep so that the plastic wave is resolved also reduces the velocity error in terms of magnitude and spatial extent. However, the parameter set required for convergence to within the error bars of satellite (RGPS) deformation fields is impractical for use in climate model simulations. The behavior of the EVP* method is analogous to that of the EVP method except that it is not possible to reduce the damping timescale with α = β.

  15. Lake sediment-based Late Holocene glacier reconstruction reveals medieval retreat and two-phase Little Ice Age on subantarctic South Georgia

    Science.gov (United States)

    van der Bilt, W. G. M.; Bakke, J.; Werner, J.; Paasche, O.; Rosqvist, G. N.; Vatle, S. S.

    2016-12-01

    Southern Ocean climate is rapidly changing. Yet beyond the instrumental period (± 100 years), our comprehension of climate variability in the region is restricted by a lack of high-resolution paleoclimate records. Alpine glaciers, ubiquitous on Southern Ocean islands, may provide such data as they rapidly respond to climate shifts, recording attendant changes in extent by variations in glacial erosion. Rock flour, the fine-grained fraction of this process, is suspended in meltwater streams and transfers this signal to the sediments of downstream lakes, continuously recording glacier history. Here, we use this relationship and present the first reconstruction of the Late Holocene (1250 cal. yr BP - present) glacier history of the Southern Ocean island of South Georgia, using sediments from the glacier-fed Middle Hamberg lake. Variations are resolved on multi-centennial scales due to robust chronological control. To fingerprint a glacial erosion signal, we employed a set of routinely used physical, geochemical and magnetic parameters. Using Titanium counts, validated against changes in sediment density and grain size distribution, we continuously reconstruct glacier variations over the past millennium. Refining local moraine evidence and supporting evidence from other Southern Hemisphere sites, this study shows a progressive diminishing of consecutive Late Holocene advances. These include a two-stage Little Ice Age, in agreement with other Southern Hemisphere glacier evidence. The presented record furthermore captures an unreported retreat phase behind present limits around 500 cal. yr BP.

  16. Coliquefaction of coal, tar sand bitumen and plastic (interaction among coal, bitumen and plastic); Sekitan/tar sand bitumen/plastic no kyoekika ni okeru kyozon busshitsu no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Okuyama, Y.; Matsubara, K. [NKK Corp., Tokyo (Japan); Kamo, T.; Sato, Y. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    For the improvement of economy, coliquefaction of coal, tar sand bitumen and plastic was performed under low hydrogen pressure, to investigate the influence of interaction among these on the liquefaction characteristics. For comparison, coliquefaction was also performed under the hydrogen pressure same as the NEDOL process. In addition, for clarifying its reaction mechanism, coliquefaction of dibenzyl and plastic was performed as a model experiment, to illustrate the distribution of products and composition of oil, and to discuss the interaction between dibenzyl and various plastics, and between various plastics. Under direct coal liquefaction conditions, coprocessing of Tanito Harum coal, Athabasca tar sand and plastic was carried out under low hydrogen pressure with an autoclave. The observed value of oil yield was higher than the calculated value based on the values from separate liquefaction of coal and plastic, which suggested the interaction between coal and the mixed plastic. The results of coliquefaction of coal, tar sand bitumen and plastic could be explained from the obtained oil yield and its composition by the coliquefaction of dibenzyl and plastic. 2 refs., 3 tabs.

  17. IL-6 is Upregulated in Late-Stage Disease in Monkeys Experimentally Infected with Trypanosoma brucei rhodesiense

    Directory of Open Access Journals (Sweden)

    Dawn Nyawira Maranga

    2013-01-01

    Full Text Available The management of human African trypanosomiasis (HAT is constrained by lack of simple-to-use diagnostic, staging, and treatment tools. The search for novel biomarkers is, therefore, essential in the fight against HAT. The current study aimed at investigating the potential of IL-6 as an adjunct parameter for HAT stage determination in vervet monkey model. Four adult vervet monkeys (Chlorocebus aethiops were experimentally infected with Trypanosoma brucei rhodesiense and treated subcuratively at 28 days after infection (dpi to induce late stage disease. Three noninfected monkeys formed the control group. Cerebrospinal fluid (CSF and blood samples were obtained at weekly intervals and assessed for various biological parameters. A typical HAT-like infection was observed. The late stage was characterized by significant (P<0.05 elevation of CSF IL-6, white blood cell count, and total protein starting 35 dpi with peak levels of these parameters coinciding with relapse parasitaemia. Brain immunohistochemical staining revealed an increase in brain glial fibrillary acidic protein expression indicative of reactive astrogliosis in infected animals which were euthanized in late-stage disease. The elevation of IL-6 in CSF which accompanied other HAT biomarkers indicates onset of parasite neuroinvasion and show potential for use as an adjunct late-stage disease biomarker in the Rhodesian sleeping sickness.

  18. A study of serrated plastic flow behavior in an aluminum-lithium binary alloy

    International Nuclear Information System (INIS)

    Sun, D.L.; Yang, D.Z.; Lei, T.Q.

    1990-01-01

    The serrated plastic flow behavior of an Al-2.73wt%Li alloy at various aging conditions is investigated. The stress-strain curve of the alloy is examined using an Instron machine. The microstructure of the alloy before and after deformation is observed using a transmission electron microscope. It has been shown that the stress-strain curve in the alloy is serrated and both time and/or temperature of aging affect the formation of serrations. The δ' phase (Al 3 Li) which is induced by plastic deformation precipitates along dislocations. The formation mechanism of the serrated stress-strain curve in the Al-Li binary alloy is discussed. (orig.)

  19. Frequency modulation reveals the phasing of orbital eccentricity during Cretaceous Oceanic Anoxic Event II and the Eocene hyperthermals

    Science.gov (United States)

    Laurin, Jiří; Meyers, Stephen R.; Galeotti, Simone; Lanci, Luca

    2016-05-01

    Major advances in our understanding of paleoclimate change derive from a precise reconstruction of the periods, amplitudes and phases of the 'Milankovitch cycles' of precession, obliquity and eccentricity. While numerous quantitative approaches exist for the identification of these astronomical cycles in stratigraphic data, limitations in radioisotopic dating, and instability of the theoretical astronomical solutions beyond ∼50 Myr ago, can challenge identification of the phase relationships needed to constrain climate response and anchor floating astrochronologies. Here we demonstrate that interference patterns accompanying frequency modulation (FM) of short eccentricity provide a robust basis for identifying the phase of long eccentricity forcing in stratigraphic data. One- and two-dimensional models of sedimentary distortion of the astronomical signal are used to evaluate the veracity of the FM method, and indicate that pristine eccentricity FM can be readily distinguished in paleo-records. Apart from paleoclimatic implications, the FM approach provides a quantitative technique for testing and calibrating theoretical astronomical solutions, and for refining chronologies for the deep past. We present two case studies that use the FM approach to evaluate major carbon-cycle perturbations of the Eocene and Late Cretaceous. Interference patterns in the short-eccentricity band reveal that Eocene hyperthermals ETM2 ('Elmo'), H2, I1 and ETM3 (X; ∼52-54 Myr ago) were associated with maxima in the 405-kyr cycle of orbital eccentricity. The same eccentricity configuration favored regional anoxic episodes in the Mediterranean during the Middle and Late Cenomanian (∼94.5-97 Myr ago). The initial phase of the global Oceanic Anoxic Event II (OAE II; ∼93.9-94.5 Myr ago) coincides with maximum and falling 405-kyr eccentricity, and the recovery phase occurs during minimum and rising 405-kyr eccentricity. On a Myr scale, the event overlaps with a node in eccentricity

  20. Novice Collaboration in Solo and Accompaniment Improvisation

    DEFF Research Database (Denmark)

    Hansen, Anne-Marie; Andersen, Hans Jørgen

    2012-01-01

    -accompaniment relationship. Results of interaction data and video analysis show that 1) teams related to each other through their experience with verbal conversation, 2) users searched for harmonic relations and 3) were able to establish rhythmical grounding. The paper concludes with some design guidelines for future solo...... in order to understand how future shared electronic music instruments can be de-signed to encourage non-musicians to engage in social action through music improvisation. A combination of quantitative and qualitative analysis was used to find characteristics in co-expression found in a solo......-accompaniment shared improvisation interfaces: How real time analysis of co-expression can be mapped to ad-ditional sound feedback that supports, strengthens and evolves co-expression in improvisation....

  1. A review of plastic waste biodegradation.

    Science.gov (United States)

    Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

    2005-01-01

    With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

  2. Recycling of plastics

    Energy Technology Data Exchange (ETDEWEB)

    Kaminsky, W; Menzel, J; Sinn, H

    1976-01-01

    Considering the shortage of raw materials and environmental pollution, the recycling of plastic waste is a very important topic. Pilot plants for research in Funabashi Japan, Franklin (Ohio) U.S.A., and the R 80-process of Krauss Maffei, W. Germany, have demonstrated the possibility of reclaiming plastics from refuse. Old tires and waste from the plastic producing and manufacturing industries are readily available. The pyrolysis of plastic yields gaseous and liquid products, and the exploitation of this cracking reaction has been demonstrated by pilot plants in Japan and Great Britain. Further laboratory scale experiments are taking place in W. Germany. In continuous fluidized beds and in molten salts, polyethylene, polypropylene, polyvinylchloride, polystyrene and rubber are pyrolysed and better than 98 percent conversion is obtained. Up to 40 percent of the feed can be obtained as aromatic compounds, and a pilot plant is under construction. As a first step PVC-containing material can be almost quantitatively dehydrochlorinated.

  3. Plastics and environment

    International Nuclear Information System (INIS)

    Avenas, P.

    1996-01-01

    Synthetic organic polymers, such as plastics, PVC, polyamides etc are considered less ecological than natural materials such as wood. Other artificial materials such as metals, glass or biodegradable plastics have also a better image than petroleum products. This short paper demonstrates that the manufacturing or the transport of every material uses energy and that the complete energy balance sheet of a plastic bottle, for instance, is more favourable than the one of a glass bottle. Plastic materials are also easily valorized and recycled and part of the energy spent during manufacturing can be recovered during incineration for district heating. During the life-cycle of such a synthetic material, the same petroleum quantity can be used twice which leads to less negative effects on the environment. Finally, the paper focusses on the problem of biodegradable materials which are not degradable when buried under several meters of wastes and which are a nuisance to recycling. (J.S.)

  4. Stem cell plasticity.

    Science.gov (United States)

    Lakshmipathy, Uma; Verfaillie, Catherine

    2005-01-01

    The central dogma in stem cell biology has been that cells isolated from a particular tissue can renew and differentiate into lineages of the tissue it resides in. Several studies have challenged this idea by demonstrating that tissue specific cell have considerable plasticity and can cross-lineage restriction boundary and give rise to cell types of other lineages. However, the lack of a clear definition for plasticity has led to confusion with several reports failing to demonstrate that a single cell can indeed differentiate into multiple lineages at significant levels. Further, differences between results obtained in different labs has cast doubt on some results and several studies still await independent confirmation. In this review, we critically evaluate studies that report stem cell plasticity using three rigid criteria to define stem cell plasticity; differentiation of a single cell into multiple cell lineages, functionality of differentiated cells in vitro and in vivo, robust and persistent engraft of transplanted cells.

  5. Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative

    Directory of Open Access Journals (Sweden)

    Domenico Sagnelli

    2017-09-01

    Full Text Available Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO, an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi© plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material.

  6. Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative

    Science.gov (United States)

    Sagnelli, Domenico; Kemmer, Gerdi Christine; Holse, Mette; Hebelstrup, Kim H.; Bao, Jinsong; Stelte, Wolfgang; Bjerre, Anne-Belinda; Blennow, Andreas

    2017-01-01

    Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi© plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material. PMID:28973963

  7. Cross-Linked Amylose Bio-Plastic: A Transgenic-Based Compostable Plastic Alternative.

    Science.gov (United States)

    Sagnelli, Domenico; Hooshmand, Kourosh; Kemmer, Gerdi Christine; Kirkensgaard, Jacob J K; Mortensen, Kell; Giosafatto, Concetta Valeria L; Holse, Mette; Hebelstrup, Kim H; Bao, Jinsong; Stelte, Wolfgang; Bjerre, Anne-Belinda; Blennow, Andreas

    2017-09-30

    Bio-plastics and bio-materials are composed of natural or biomass derived polymers, offering solutions to solve immediate environmental issues. Polysaccharide-based bio-plastics represent important alternatives to conventional plastic because of their intrinsic biodegradable nature. Amylose-only (AO), an engineered barley starch with 99% amylose, was tested to produce cross-linked all-natural bioplastic using normal barley starch as a control. Glycerol was used as plasticizer and citrate cross-linking was used to improve the mechanical properties of cross-linked AO starch extrudates. Extrusion converted the control starch from A-type to Vh- and B-type crystals, showing a complete melting of the starch crystals in the raw starch granules. The cross-linked AO and control starch specimens displayed an additional wide-angle diffraction reflection. Phospholipids complexed with Vh-type single helices constituted an integrated part of the AO starch specimens. Gas permeability tests of selected starch-based prototypes demonstrated properties comparable to that of commercial Mater-Bi © plastic. The cross-linked AO prototypes had composting characteristics not different from the control, indicating that the modified starch behaves the same as normal starch. The data shows the feasibility of producing all-natural bioplastic using designer starch as raw material.

  8. 22 CFR 40.102 - Guardian required to accompany excluded alien.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Guardian required to accompany excluded alien. 40.102 Section 40.102 Foreign Relations DEPARTMENT OF STATE VISAS REGULATIONS PERTAINING TO BOTH... Guardian required to accompany excluded alien. INA 212(a)(9)(B) is not applicable at the time of visa...

  9. Collective flow measured with the Plastic Ball

    International Nuclear Information System (INIS)

    Ritter, H.G.; Gutbrod, H.H.; Kampert, K.H.; Kolb, B.; Poskanzer, A.M.; Schicker, R.; Schmidt, H.R.; Siemiarczuk, T.

    1989-08-01

    The experimental results from the Plastic Ball detector have contributed vastly to the understanding of the reaction mechanism of nuclear collisions at several hundred MeV per nucleon. The discovery of the collective flow phenomena (bounce-off of spectator fragments, side-splash in the reaction plane, and squeeze-out out of the reaction plane), as they were predicted by hydrodynamical models, has led to the experimental observation of compressed nuclear matter, which is a necessary condition before one can study the equation of state in detail and search for phase transitions at higher energies. 39 refs., 9 figs., 1 tab

  10. Plastics and beaches: A degrading relationship

    International Nuclear Information System (INIS)

    Corcoran, Patricia L.; Biesinger, Mark C.; Grifi, Meriem

    2009-01-01

    Plastic debris in Earth's oceans presents a serious environmental issue because breakdown by chemical weathering and mechanical erosion is minimal at sea. Following deposition on beaches, plastic materials are exposed to UV radiation and physical processes controlled by wind, current, wave and tide action. Plastic particles from Kauai's beaches were sampled to determine relationships between composition, surface textures, and plastics degradation. SEM images indicated that beach plastics feature both mechanically eroded and chemically weathered surface textures. Granular oxidation textures were concentrated along mechanically weakened fractures and along the margins of the more rounded plastic particles. Particles with oxidation textures also produced the most intense peaks in the lower wavenumber region of FTIR spectra. The textural results suggest that plastic debris is particularly conducive to both chemical and mechanical breakdown in beach environments, which cannot be said for plastics in other natural settings on Earth

  11. Art and Plastic Surgery.

    Science.gov (United States)

    Fernandes, Julio Wilson; Metka, Susanne

    2016-04-01

    The roots of science and art of plastic surgery are very antique. Anatomy, drawing, painting, and sculpting have been very important to the surgery and medicine development over the centuries. Artistic skills besides shape, volume, and lines perception can be a practical aid to the plastic surgeons' daily work. An overview about the interactions between art and plastic surgery is presented, with a few applications to rhinoplasty, cleft lip, and other reconstructive plastic surgeries. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

  12. Urea-temperature phase diagrams capture the thermodynamics of denatured state expansion that accompany protein unfolding

    Science.gov (United States)

    Tischer, Alexander; Auton, Matthew

    2013-01-01

    We have analyzed the thermodynamic properties of the von Willebrand factor (VWF) A3 domain using urea-induced unfolding at variable temperature and thermal unfolding at variable urea concentrations to generate a phase diagram that quantitatively describes the equilibrium between native and denatured states. From this analysis, we were able to determine consistent thermodynamic parameters with various spectroscopic and calorimetric methods that define the urea–temperature parameter plane from cold denaturation to heat denaturation. Urea and thermal denaturation are experimentally reversible and independent of the thermal scan rate indicating that all transitions are at equilibrium and the van't Hoff and calorimetric enthalpies obtained from analysis of individual thermal transitions are equivalent demonstrating two-state character. Global analysis of the urea–temperature phase diagram results in a significantly higher enthalpy of unfolding than obtained from analysis of individual thermal transitions and significant cross correlations describing the urea dependence of and that define a complex temperature dependence of the m-value. Circular dichroism (CD) spectroscopy illustrates a large increase in secondary structure content of the urea-denatured state as temperature increases and a loss of secondary structure in the thermally denatured state upon addition of urea. These structural changes in the denatured ensemble make up ∼40% of the total ellipticity change indicating a highly compact thermally denatured state. The difference between the thermodynamic parameters obtained from phase diagram analysis and those obtained from analysis of individual thermal transitions illustrates that phase diagrams capture both contributions to unfolding and denatured state expansion and by comparison are able to decipher these contributions. PMID:23813497

  13. Plastics recycling: challenges and opportunities.

    Science.gov (United States)

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-07-27

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  14. Plastics recycling: challenges and opportunities

    Science.gov (United States)

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-01-01

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  15. Transient dysautonomia in an acute phase of encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Ichimiya, Yuko; Kaku, Noriyuki; Sakai, Yasunari; Yamashita, Fumiya; Matsuoka, Wakato; Muraoka, Mamoru; Akamine, Satoshi; Mizuguchi, Soichi; Torio, Michiko; Motomura, Yoshitomo; Hirata, Yuichiro; Ishizaki, Yoshito; Sanefuji, Masafumi; Torisu, Hiroyuki; Takada, Hidetoshi; Maehara, Yoshihiko; Ohga, Shouichi

    2017-08-01

    Paroxysmal sympathetic hyperactivity (PSH) is a dysautonomic condition that is associated with various types of acquired brain injuries. Traumatic brain lesions have been documented as the leading cause of PSH. However, detailed clinical features of pediatric PSH caused by intrinsic brain lesions remain to be elusive. We present a 3-year-old boy, who had been diagnosed as having cerebral palsy, developmental delay and epilepsy after perinatal hypoxia-induced brain injury. He developed status epilepticus with fever on the third day of respiratory infection. Whereas the seizure was terminated by systemic infusion of midazolam, consciousness remained disturbed for the next 48h. Serial magnetic resonance imaging studies revealed that acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) evolved on 3days after the seizure. Therapeutic hypothermia was immediately introduced, however, the brain lesion extended to the whole subcortical white matters on day 8. The intermittent bilateral dilation of pupils with increased blood pressure and tachycardia were observed until day 12. Real-time monitoring of electroencephalograms ruled out the recurrent attacks of seizures. The abnormal signs of autonomic nervous system gradually ceased and never relapsed after recovery from the hypothermia. PSH or a transient condition of dysautonomia may emerge and persist during the acute phase of AESD. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  16. Analysis of phthalate migration to food simulants in plastic containers during microwave operations.

    Science.gov (United States)

    Moreira, Miriany A; André, Leiliane C; Cardeal, Zenilda L

    2013-12-30

    Phthalates used as plasticizers in the manufacture of household containers can potentially be transferred to foods that are stored or heated in these plastic containers. Phthalates are endocrine disruptor compounds (EDC) and are found in very low concentrations in foods, thus, highly sensitive analytical techniques are required for their quantification. This study describes the application of a new method developed for analyzing the migration of dibutylphthalate (DBP) and benzylbutylphthalate (BBP) from plastic food containers into liquid food simulants. This new method employs the technique of solid phase microextraction cooled with liquid nitrogen. The analysis was conducted by gas chromatography/mass spectrometry (GC/MS) using a polyacrylate fiber. Ultrapure water was used as a simulant for liquids foods, and both new and used plastic containers were placed in a domestic microwave oven for different periods of time at different power levels. The limits of detection for DBP and BBP were 0.08 µg/L and 0.31 µg/L, respectively. BBP was not found in the samples that were analyzed. DBP was found in concentrations ranging from containers that were used for a prolonged time, which correlated with increasing heating time.

  17. Plastic pollutants in water environment

    OpenAIRE

    Mrowiec Bożena

    2017-01-01

    Nowadays, wide applications of plastics result in plastic waste being present in the water environment in a wide variety of sizes. Plastic wastes are in water mainly as microplastics (the size range of 1 nm to < 5 mm). Microplastics have been recognized as an emerging threat, as well as ecotoxicological and ecological risk for water ecosystems. In this review are presented some of the physicochemical properties of plastic materials that determine their toxic effect on the aquatic environment....

  18. DEVELOPMENT OF PLASTIC SURGERY.

    Science.gov (United States)

    Pećanac, Marija Đ

    2015-01-01

    Plastic surgery is a medical specialty dealing with corrections of defects, improvements in appearance and restoration of lost function. Ancient times. The first recorded account of reconstructive plastic surgery was found in ancient Indian Sanskrit texts, which described reconstructive surgeries of the nose and ears. In ancient Greece and Rome, many medicine men performed simple plastic cosmetic surgeries to repair damaged parts of the body caused by war mutilation, punishment or humiliation. In the Middle Ages, the development of all medical braches, including plastic surgery was hindered. New age. The interest in surgical reconstruction of mutilated body parts was renewed in the XVIII century by a great number of enthusiastic and charismatic surgeons, who mastered surgical disciplines and became true artists that created new forms. Modern era. In the XX century, plastic surgery developed as a modern branch in medicine including many types of reconstructive surgery, hand, head and neck surgery, microsurgery and replantation, treatment of burns and their sequelae, and esthetic surgery. Contemporary and future plastic surgery will continue to evolve and improve with regenerative medicine and tissue engineering resulting in a lot of benefits to be gained by patients in reconstruction after body trauma, oncology amputation, and for congenital disfigurement and dysfunction.

  19. A work criterion for plastic collapse

    International Nuclear Information System (INIS)

    Muscat, Martin; Mackenzie, Donald; Hamilton, Robert

    2003-01-01

    A new criterion for evaluating limit and plastic loads in pressure vessel design by analysis is presented. The proposed criterion is based on the plastic work dissipated in the structure as loading progresses and may be used for structures subject to a single load or a combination of multiple loads. Example analyses show that limit and plastic loads given by the plastic work criterion are robust and consistent. The limit and plastic loads are determined purely by the inelastic response of the structure and are not influenced by the initial elastic response: a problem with some established plastic criteria

  20. Radiation grafting of hydrophilic monomers on to plasticized poly(vinyl chloride) sheets: Pt. 1

    International Nuclear Information System (INIS)

    Kalliyana Krishnan, V.; Jayakrishnan, A.; Francis, J.D.

    1990-01-01

    Medical-grade plasticized polyvinyl chloride (PVC) sheets were surface modified using gamma-radiation grafting of a combination of hydrophilic monomers based on 2-hydroxyethyl methacrylate (HEMA) and N-vinyl pyrrolidone (NVP). The properties of the modified surfaces were evaluated using contact angle measurements, phase-contrast photomicroscopy and scanning electron microscopy. Surface energy calculations indicated that the surfaces became highly hydrophilic when grafted with even a 1% (v/v) solution of HEMA-NVP combination in the presence of 0.005 M CuSO 4 . Migration of the plasticizer di(2-ethylhexyl phthalate) from the grafted sheets was examined in hydrocarbon solvents such as n-hexane, n-heptane and n-octane and in extractant media such as cotton seed oil and polyethylene glycol-400 (PEG-400). The migration was found to be 0 C over a period of 5 h. Accelerated leaching studies in cotton seed oil and PEG-400 demonstrated that virtually no plasticizer migrated out in the former over a period of 96 h whereas the rate of migration in the latter medium showed only a mild reduction. The migration behaviour was Fickian in nature for grafted sheets. The method described may be useful as a simple, versatile technique for preventing plasticizer migration from plasticized PVC for medical applications. (author)

  1. A Coupled Plastic Damage Model for Concrete considering the Effect of Damage on Plastic Flow

    OpenAIRE

    Zhou, Feng; Cheng, Guangxu

    2015-01-01

    A coupled plastic damage model with two damage scalars is proposed to describe the nonlinear features of concrete. The constitutive formulations are developed by assuming that damage can be represented effectively in the material compliance tensor. Damage evolution law and plastic damage coupling are described using the framework of irreversible thermodynamics. The plasticity part is developed without using the effective stress concept. A plastic yield function based on the true stress is ado...

  2. Compton Composites Late in the Early Universe

    Directory of Open Access Journals (Sweden)

    Frederick Mayer

    2014-07-01

    Full Text Available Beginning roughly two hundred years after the big-bang, a tresino phase transition generated Compton-scale composite particles and converted most of the ordinary plasma baryons into new forms of dark matter. Our model consists of ordinary electrons and protons that have been bound into mostly undetectable forms. This picture provides an explanation of the composition and history of ordinary to dark matter conversion starting with, and maintaining, a critical density Universe. The tresino phase transition started the conversion of ordinary matter plasma into tresino-proton pairs prior to the the recombination era. We derive the appropriate Saha–Boltzmann equilibrium to determine the plasma composition throughout the phase transition and later. The baryon population is shown to be quickly modified from ordinary matter plasma prior to the transition to a small amount of ordinary matter and a much larger amount of dark matter after the transition. We describe the tresino phase transition and the origin, quantity and evolution of the dark matter as it takes place from late in the early Universe until the present.

  3. Plastic solid waste utilization technologies: A Review

    Science.gov (United States)

    Awasthi, Arun Kumar; Shivashankar, Murugesh; Majumder, Suman

    2017-11-01

    Plastics are used in more number of applications in worldwide and it becomes essential part of our daily life. In Indian cities and villages people use the plastics in buying vegetable as a carry bag, drinking water bottle, use of plastic furniture in home, plastics objects uses in kitchen, plastic drums in packing and storage of the different chemicals for industrial use, use plastic utensils in home and many more uses. After usage of plastics it will become part of waste garbage and create pollution due to presence of toxic chemicals and it will be spread diseases and give birth to uncontrolled issues in social society. In current scenario consumption of plastic waste increasing day by day and it is very difficult to manage the plastic waste. There are limited methodologies available for reutilization of plastic waste again. Such examples are recycling, landfill, incineration, gasification and hydrogenation. In this paper we will review the existing methodologies of utilization of plastic waste in current scenario

  4. Echinoderms display morphological and behavioural phenotypic plasticity in response to their trophic environment.

    Directory of Open Access Journals (Sweden)

    Adam D Hughes

    Full Text Available The trophic interactions of sea urchins are known to be the agents of phase shifts in benthic marine habitats such as tropical and temperate reefs. In temperate reefs, the grazing activity of sea urchins has been responsible for the destruction of kelp forests and the formation of 'urchin barrens', a rocky habitat dominated by crustose algae and encrusting invertebrates. Once formed, these urchin barrens can persist for decades. Trophic plasticity in the sea urchin may contribute to the stability and resilience of this alternate stable state by increasing diet breadth in sea urchins. This plasticity promotes ecological connectivity and weakens species interactions and so increases ecosystem stability. We test the hypothesis that sea urchins exhibit trophic plasticity using an approach that controls for other typically confounding environmental and genetic factors. To do this, we exposed a genetically homogenous population of sea urchins to two very different trophic environments over a period of two years. The sea urchins exhibited a wide degree of phenotypic trophic plasticity when exposed to contrasting trophic environments. The two populations developed differences in their gross morphology and the test microstructure. In addition, when challenged with unfamiliar prey, the response of each group was different. We show that sea urchins exhibit significant morphological and behavioural phenotypic plasticity independent of their environment or their nutritional status.

  5. Plastic Pollution from Ships

    OpenAIRE

    Čulin, Jelena; Bielić, Toni

    2016-01-01

    The environmental impact of shipping on marine environment includes discharge of garbage. Plastic litter is of particular concern due to abundance, resistance to degradation and detrimental effect on marine biota. According to recently published studies, a further research is required to assess human health risk. Monitoring data indicate that despite banning plastic disposal at sea, shipping is still a source of plastic pollution. Some of the measures to combat the problem are discussed.

  6. Practical solution of plastic deformation problems in elastic-plastic range

    Science.gov (United States)

    Mendelson, A; Manson, S

    1957-01-01

    A practical method for solving plastic deformation problems in the elastic-plastic range is presented. The method is one of successive approximations and is illustrated by four examples which include a flat plate with temperature distribution across the width, a thin shell with axial temperature distribution, a solid cylinder with radial temperature distribution, and a rotating disk with radial temperature distribution.

  7. Interactions between the phase stress and the grain-orientation-dependent stress in duplex stainless steel during deformation

    International Nuclear Information System (INIS)

    Jia, N.; Peng, R. Lin; Wang, Y.D.; Chai, G.C.; Johansson, S.; Wang, G.; Liaw, P.K.

    2006-01-01

    The development of phase stress and grain-orientation-dependent stress under uniaxial compression was investigated in a duplex stainless steel consisting of austenite and ferrite. Using in situ neutron diffraction measurements, the strain response of several h k l planes to the applied compressive stress was mapped as a function of applied stress and sample direction. Analysis based on the experimental results and elastoplastic self-consistent simulations shows that phase stresses of thermal origin further increase during elastic loading but decrease with increased plastic deformation. Grain-orientation-dependent stresses become significant in both austenite and ferrite after loading into the plastic region. After unloading from the plastic regime, a considerable intergranular stress remains in the austenitic phase and dominates over the phase stress. This study provides fundamental experimental inputs for future micromechanical modeling aiming at the evaluation and prediction of the mechanical performance of multiphase materials

  8. Evidence of significant energy input in the late phase of a solar flare from NuSTAR x-ray observations

    DEFF Research Database (Denmark)

    Kuhar, Matej; Krucker, Säm; Hannah, Iain G.

    2017-01-01

    -size solar flare 1 day before the observations, at ∼18 UT on 2014 December 10, with the post-flare loops still visible at the time of NuSTAR observations. The time evolution of the source emission in the SDO/AIA 335 Å channel reveals the characteristics of an extreme-ultraviolet late-phase event, caused......We present observations of the occulted active region AR 12222 during the third Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaign on 2014 December 11, with concurrent Solar Dynamics Observatory (SDO)/AIA and FOXSI-2 sounding rocket observations. The active region produced a medium...... by the continuous formation of new post-flare loops that arch higher and higher in the solar corona. The spectral fitting of NuSTAR observations yields an isothermal source, with temperature 3.8–4.6 MK, emission measure (0.3–1.8) × 1046 cm−3, and density estimated at (2.5–6.0) × 108 cm−3. The observed AIA fluxes...

  9. Extruding plastic scintillator at Fermilab

    International Nuclear Information System (INIS)

    Pla-Dalmau, Anna; Bross, Alain D.; Rykalin, Viktor V.

    2003-01-01

    An understanding of the costs involved in the production of plastic scintillators and the development of a less expensive material have become necessary with the prospects of building very large plastic scintillation detectors. Several factors contribute to the high cost of plastic scintillating sheets, but the principal reason is the labor-intensive nature of the manufacturing process. In order to significantly lower the costs, the current casting procedures had to be abandoned. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. This concept was tested and high quality extruded plastic scintillator was produced. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. This paper will discuss the characteristics of extruded plastic scintillator and its raw materials, the different manufacturing techniques and the current R andD program at Fermilab

  10. Applications and societal benefits of plastics.

    Science.gov (United States)

    Andrady, Anthony L; Neal, Mike A

    2009-07-27

    This article explains the history, from 1600 BC to 2008, of materials that are today termed 'plastics'. It includes production volumes and current consumption patterns of five main commodity plastics: polypropylene, polyethylene, polyvinyl chloride, polystyrene and polyethylene terephthalate. The use of additives to modify the properties of these plastics and any associated safety, in use, issues for the resulting polymeric materials are described. A comparison is made with the thermal and barrier properties of other materials to demonstrate the versatility of plastics. Societal benefits for health, safety, energy saving and material conservation are described, and the particular advantages of plastics in society are outlined. Concerns relating to littering and trends in recycling of plastics are also described. Finally, we give predictions for some of the potential applications of plastic over the next 20 years.

  11. Problems with radiation protection concerning volunteers accompanying radiological patients

    International Nuclear Information System (INIS)

    Adrian Daoud

    2008-01-01

    Full text: The purpose of this work is to point out, within the framework of the Radiation Protection guidelines, the irregular situation of the 'volunteer' or 'accompanying person' who accompanies anyone requiring medical treatment with ionising radiation, as well as to suggest a possible justification for such role. It should be noted that most of these persons are subject to ionising radiation without knowing anything about the effects that it could cause on them, so that their condition could be hardly considered as 'voluntary'. There are several circumstances under which the presence of accompanying persons is required, being different among them. Several examples could be mentioned such as: those who are accompanying a direct relative (family bonds), those who are acting in service during their normal work (social workers, policemen) and even those who are forced by unusual under an accidental situation. The qualitative classification that radiological protection established in society concerning radiation risks for people in general enables to set mechanisms of justification, optimisation and dose limitation for each category, being perfectly identified which of them each person belongs to. But the figure of 'accompanying person' has been excluded from such characterisation. They are subject to radiation exposure without knowing it, or without having any information concerning the potential risks. For them, no balance between the net benefit of an adequate medical treatment versus potential health detriment may be applied as for the case of a patient. Thus, their exposure could be not justified. It is not the purpose of this work to question radiological medicine or its practices, but to clarify certain aspects involving members of the public in general, patients and members of the radiological community, as well as to propose lines of action concerning this subject. We conclude that it is not the volunteer who should decide about medical actions, a role

  12. Plastic pollutants in water environment

    Directory of Open Access Journals (Sweden)

    Mrowiec Bożena

    2017-12-01

    Full Text Available Nowadays, wide applications of plastics result in plastic waste being present in the water environment in a wide variety of sizes. Plastic wastes are in water mainly as microplastics (the size range of 1 nm to < 5 mm. Microplastics have been recognized as an emerging threat, as well as ecotoxicological and ecological risk for water ecosystems. In this review are presented some of the physicochemical properties of plastic materials that determine their toxic effect on the aquatic environment. Wastewater treatment plants (WWTPs are mentioned as one of main sources of microplastics introduced into fresh water, and rivers are the pathways for the transportation of the pollutants to seas and oceans. But, effluents from tertiary wastewater treatment facilities can contain only minimally microplastic loads. The issue of discharge reduction of plastic pollutants into water environment needs activities in the scope of efficient wastewater treatment, waste disposal, recycling of plastic materials, education and public involvement.

  13. Track treeing mechanism and plastic zone in solid Part 1: Initial development of plastic zone

    International Nuclear Information System (INIS)

    Li Boyang

    2008-01-01

    After neutron exposure and chemical etching in advance, latent tracks of recoil nucleon develop into pits on CR39 surface. During electrochemical etching, plastic zone is formed at top of pits. Some