Deformation and Failure of Amorphous Solidlike Materials

Since the 1970's, theories of deformation and failure of amorphous, solidlike materials have started with models in which stress-driven, molecular rearrangements occur at localized flow defects via "shear transformations". This picture is the basis for the modern theory of "shear transformation zones" (STZ's), which is the focus of this review. We begin by describing the structure of the theory in general terms and by showing several applications, specifically: interpretation of stress-strain measurements for a bulk metallic glass, analysis of numerical simulations of shear banding, and the use of the STZ equations of motion in free-boundary calculations. In the second half of this article, we focus for simplicity on what we call an "athermal" model of amorphous plasticity, and use that model to illustrate how the STZ theory emerges within a systematic formulation of nonequilibrium thermodynamics.Comment: 28 pages, 4 figures, submitted to Annual Reviews of Condensed Matter Physic

Effect of Chronic Alcohol Consumption on Phosphatidylcholine Hydroperoxide Content of Rat Liver and Brain

Purpose: To investigate the correlation between alcohol-induced oxidative stress and tissue phosphatidylcholine hydroperoxide (PC-OOH) content of rat liver and brain.Methods: Ten Wistar rats were divided into two groups: one group was given 20 % ethanol (5 g/kg) and the other the same volume of normal saline, orally once a day for 6 weeks. Catalase activity, malondialdehyde (MDA) content, total antioxidant capacity (TAC) and PC-OOH content of liver and brain were determined.Results: The ethanol-treated group had lower catalase activity and total antioxidant capacity. MDA level in the liver was 0.33 ± 0.07 μM/mg protein which is significantly (p < 0.05) higher than that of the control group (0.17 ± 0.06 μM/mg protein), but in brain, there was no significant difference. PC-OOH level in the ethanol-treated group was 46.91 ± 12.87 pmol/mg in liver and 71.97 ± 26.12 pmol/mg protein in brain while PC-OOH level of control group was 21.40 ± 10.71 pmol/mg protein in liver and that in brain was 25.29 ± 5.67 pmol/mg protein pmol. Thus, PC-OOH levels in both liver and brain were significantly (p < 0.05) higher than that of control group. PC-OOH content in the liver and brain correlated significantly (p < 0.05) with catalase activity and total antioxidant capacity (TAC).Conclusion: The study demonstrates that PC-OOH content in liver and brain tissues may be a marker for alcohol-induced oxidative stress.Keywords: Alcohol Toxicity, Oxidative Stress, Phosphatidylcholine Hydroperoxide, Liver, Brain, Biomarke

Carbon nanotubes grown in situ by a novel catalytic method

Carbon nanotubes can be produced by the catalytic decomposition of hydrocarbons on small metal particles. However, nanotubes are generally produced together with non-tubular filaments and tubes coated by pyrolytic carbon. We propose a novel catalyst method for the in situ production, in a composite powder, of a huge amount of single- and multiwalled carbon nanotubes, having a diameter between 1.5 and 15 nm and arranged in bundles up to 100 mm long. We anticipate that dense materials prepared from such composite powders could have interesting mechanical and physical properties

The ubiquitin ligase TRIM27 functions as a host restriction factor antagonized by Mycobacterium tuberculosis PtpA during mycobacterial infection

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Antikaon production in nucleon-nucleon reactions near threshold

The antikaon production cross section from nucleon-nucleon reactions near threshold is studied in a meson exchange model. We include both pion and kaon exchange, but neglect the interference between the amplitudes. In case of pion exchange the antikaon production cross section can be expressed in terms of the antikaon production cross section from a pion-nucleon interaction, which we take from the experimental data if available. Otherwise, a $K^*$-resonance exchange model is introduced to relate the different reaction cross sections. In case of kaon exchange the antikaon production cross section is related to the elastic $KN$ and $\bar KN$ cross sections, which are again taken from experimental measurements. We find that the one-meson exchange model gives a satisfactory fit to the available data for the $NN\to NNK\bar K$ cross section at high energies. We compare our predictions for the cross section near threshold with an earlier empirical parameterization and that from phase space models.Comment: 16 pages, LaTeX, 5 postscript figures included, submitted to Z. Phys.

Seedling emergence and establishment of Pinus sylvestris in the Mongolian forest-steppe ecotone

Syftet med studien är att undersöka och beskriva pedagogers uppfattningar av hur de skapar delaktighet och inflytande, i en kommuns förskoleverksamhet och organisation.Mina frågeställningar är hur pedagogerna beskriver sina möjligheter och hinder för att få och skapa delaktighet och inflytande, samt vilka inre och yttre faktorer som finns som påverkar möjligheten för delaktighet och inflytande.För att undersöka detta har jag valt en kvalitativ forskningsansats. Jag har genomfört semistrukturerade intervjuer med sju pedagoger. Det empiriska materialet har bearbetats kvalitativt i en empirinära ansats.I resultatet såg jag att ett större fokus på processkvaliteten behöver läggas och medvetenheten behöver ökas, kring den pedagogiska dokumentationens betydelse.Sammanfattningsvis behöver den undersökta kommunens förskolor en gemensam samsyn i hela systemet i ett förståelsebaserat och tolkande perspektiv som gynnar en långsiktig och hållbar utveckling.Participation and influence in the preschool, a study with teachers in one municipality.The purpose of this study is to explore and describe teacher’s perceptions of how they create participation and influence, in a municipality´s preschool and organization.My questions are how teachers describe their opportunities and barriers to get and create participation and influence, and what internal and external factors that affecting the ability of participation and influence.To examine this, I have chosen a qualitative research approach. I have conducted semi structured interviews, with seven teachers. The empirical data have been processed in a qualitative empirical closely approach.In the result, I found that a greater focus on process quality needs to be added and awareness needs to be increased, on the pedagogic documentations significances.In conclusion, needs the municipal preschools, which have been examined, get a common consensus of the entire system in a understanding based and interpretive perspective, that support a long term and sustainable development

A novel CO₂-responsive systemic signaling pathway controlling plant mycorrhizal symbiosis

Elevated atmospheric carbon dioxide (eCO₂) concentrations promote symbiosis between roots and arbuscular mycorrhizal fungi (AMF), modifying plant nutrient acquisition and cycling of carbon, nitrogen and phosphate. However, the biological mechanisms by which plants transmit aerial eCO₂ cues to roots, to alter the symbiotic associations remain unknown. We used a range of interdisciplinary approaches, including gene silencing, grafting, transmission electron microscopy, liquid chromatography tandem mass spectrometry (LC–MS/MS), biochemical methodologies and gene transcript analysis to explore the complexities of environmental signal transmission from the point of perception in the leaves at the apex to the roots. Here we show that eCO₂ triggers apoplastic hydrogen peroxide (H₂O₂)‐dependent auxin production in tomato shoots followed by systemic signaling that results in strigolactone biosynthesis in the roots. This redox‐auxin‐strigolactone systemic signaling cascade facilitates eCO₂‐induced AMF symbiosis and phosphate utilization. Our results challenge the current paradigm of eCO₂ effects on AMF and provide new insights into potential targets for manipulation of AMF symbiosis for high nutrient utilization under future climate change scenarios

Lactadherin blocks thrombosis and hemostasis in vivo : correlation with platelet phosphatidylserine exposure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73556/1/j.1538-7836.2008.03010.x.pd

Bowel associated dermatosis – arthritis syndrome: a case report

We report a rare case of Bowel Associated Dermatosis – Arthritis Syndrome in a young patient with complex Crohn's disease who presented with fever, arthritis, rash and worsening of diarrhea with abdominal pain, who promptly responded to a short course of steroids